TY - JOUR A1 - Marcus, U. A1 - Vogel, U. A1 - Schubert, A. A1 - Claus, H. A1 - Baetzing-Feigenbaum, J. A1 - Hellenbrand, W. A1 - Wichmann, O. T1 - A cluster of invasive meningococcal disease in young men who have sex with men in Berlin, October 2012 to May 2013 JF - Eurosurveillance N2 - No abstract available. KW - meningococcal disease Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131711 VL - 18 IS - 28 ER - TY - JOUR A1 - Peters, Simon A1 - Fohmann, Ingo A1 - Rudel, Thomas A1 - Schubert-Unkmeir, Alexandra T1 - A Comprehensive Review on the Interplay between Neisseria spp. and Host Sphingolipid Metabolites JF - Cells N2 - Sphingolipids represent a class of structural related lipids involved in membrane biology and various cellular processes including cell growth, apoptosis, inflammation and migration. Over the past decade, sphingolipids have become the focus of intensive studies regarding their involvement in infectious diseases. Pathogens can manipulate the sphingolipid metabolism resulting in cell membrane reorganization and receptor recruitment to facilitate their entry. They may recruit specific host sphingolipid metabolites to establish a favorable niche for intracellular survival and proliferation. In contrast, some sphingolipid metabolites can also act as a first line defense against bacteria based on their antimicrobial activity. In this review, we will focus on the strategies employed by pathogenic Neisseria spp. to modulate the sphingolipid metabolism and hijack the sphingolipid balance in the host to promote cellular colonization, invasion and intracellular survival. Novel techniques and innovative approaches will be highlighted that allow imaging of sphingolipid derivatives in the host cell as well as in the pathogen. KW - sphingolipids KW - host–pathogen interaction KW - Neisseria meningitidis KW - Neisseria gonorrhoeae Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250203 SN - 2073-4409 VL - 10 IS - 11 ER - TY - JOUR A1 - Claus, Heike A1 - Hubert, Kerstin A1 - Becher, Dörte A1 - Otto, Andreas A1 - Pawlik, Marie-Christin A1 - Lappann, Ines A1 - Strobel, Lea A1 - Vogel, Ulrich A1 - Johswich, Kay T1 - A homopolymeric adenosine tract in the promoter region of nspA influences factor H-mediated serum resistance in Neisseria meningitidis JF - Scientific Reports N2 - Although usually asymptomatically colonizing the human nasopharynx, the Gram-negative bacterium Neisseria meningitidis (meningococcus) can spread to the blood stream and cause invasive disease. For survival in blood, N. meningitidis evades the complement system by expression of a polysaccharide capsule and surface proteins sequestering the complement regulator factor H (fH). Meningococcal strains belonging to the sequence type (ST-) 41/44 clonal complex (cc41/44) cause a major proportion of serogroup B meningococcal disease worldwide, but they are also common in asymptomatic carriers. Proteome analysis comparing cc41/44 isolates from invasive disease versus carriage revealed differential expression levels of the outer membrane protein NspA, which binds fH. Deletion of nspA reduced serum resistance and NspA expression correlated with fH sequestration. Expression levels of NspA depended on the length of a homopolymeric tract in the nspA promoter: A 5-adenosine tract dictated low NspA expression, whereas a 6-adenosine motif guided high NspA expression. Screening German cc41/44 strain collections revealed the 6-adenosine motif in 39% of disease isolates, but only in 3.4% of carriage isolates. Thus, high NspA expression is associated with disease, but not strictly required. The 6-adenosine nspA promoter is most common to the cc41/44, but is also found in other hypervirulent clonal complexes. KW - Meningitis KW - Pathogens Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200956 VL - 9 ER - TY - JOUR A1 - Koziol, Uriel A1 - Radio, Santiago A1 - Smircich, Pablo A1 - Zarowiecki, Magdalena A1 - Fernández, Cecilia A1 - Brehm, Klaus T1 - A novel terminal-repeat retrotransposon in miniature (TRIM) is massively expressed in Echinococcus multilocularis stem cells JF - Genome Biology and Evolution N2 - Taeniid cestodes (including the human parasites Echinococcus spp. and Taenia solium) have very few mobile genetic elements (MGEs) in their genome, despite lacking a canonical PIWI pathway. The MGEs of these parasites are virtually unexplored, and nothing is known about their expression and silencing. In this work, we report the discovery of a novel family of small nonautonomous long terminal repeat retrotransposons (also known as terminal-repeat retrotransposons in miniature, TRIMs) which we have named ta-TRIM (taeniid TRIM). ta-TRIMs are only the second family of TRIM elements discovered in animals, and are likely the result of convergent reductive evolution in different taxonomic groups. These elements originated at the base of the taeniid tree and have expanded during taeniid diversification, including after the divergence of closely related species such as Echinococcus multilocularis and Echinococcus granulosus. They are massively expressed in larval stages, from a small proportion of full-length copies and from isolated terminal repeats that show transcriptional read-through into downstream regions, generating novel noncoding RNAs and transcriptional fusions to coding genes. In E. multilocularis, ta-TRIMs are specifically expressed in the germinative cells (the somatic stem cells) during asexual reproduction of metacestode larvae. This would provide a developmental mechanism for insertion of ta-TRIMs into cells that will eventually generate the adult germ line. Future studies of active and inactive ta-TRIM elements could give the first clues on MGE silencing mechanisms in cestodes. KW - Schistosoma mansoni KW - molecular characterization KW - gene conversion KW - nonautonomous KW - neoblast KW - pluripotency KW - retrotransposition KW - long noncoding RNA KW - epidermal growth factor KW - transposable elements KW - LTR retrotransposons KW - blood fluke KW - homologous recombination KW - Cestoda Taeniidae Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148306 VL - 7 IS - 8 ER - TY - JOUR A1 - Forster, Johannes A1 - Kohlmorgen, Britta A1 - Haas, Julian A1 - Weis, Philipp A1 - Breunig, Lukas A1 - Turnwald, Doris A1 - Mizaikoff, Boris A1 - Schoen, Christoph T1 - A streamlined method for the fast and cost-effective detection of bacterial pathogens from positive blood cultures for the BacT/ALERT blood culture system using the Vitek MS mass spectrometer JF - PLoS ONE N2 - Background and objective Prompt pathogen identification of blood stream infections is essential to provide appropriate antibiotic treatment. Therefore, the objective of this prospective single centre study was to establish an inexpensive, fast and accurate protocol for bacterial species identification with SDS protein-extraction directly from BacT/Alert® blood culture (BC) bottles by VitekMS®. Results Correct species identification was obtained for 198/266 (74.4%, 95%-CI = [68.8%, 79.6%]) of pathogens. The protocol was more successful in identifying 87/96 (91.4%, 95%-CI = [83.8%, 93.2%]) gram-negative bacteria than 110/167 (65.9%, 95%-CI = [58.1%, 73.0%]) gram-positive bacteria. The hands-on time for sample preparation and measurement was about 15 min for up to five samples. This is shorter than for most other protocols using a similar lysis-centrifugation approach for the combination of BacT/Alert® BC bottles and the Vitek® MS mass spectrometer. The estimated costs per sample were approx. 1.80€ which is much cheaper than for commercial kits. Conclusion This optimized protocol allows for accurate identification of bacteria directly from blood culture bottles for laboratories equipped with BacT/Alert® blood culture bottles and VitekMS® mass spectrometer. KW - bacterial pathogens KW - blood stream infections KW - BacT/ALERT Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300213 VL - 17 IS - 4 ER - TY - JOUR A1 - Atanasov, Georgi A1 - Benkert, Christoph A1 - Thelen, Armin A1 - Tappe, Dennis A1 - Frosch, Matthias A1 - Teichmann, Dieter A1 - Barth, Thomas F. E. A1 - Wittekind, Christian A1 - Schubert, Stefan A1 - Jonas, Sven T1 - Alveolar echinococcosis-spreading disease challenging clinicians: A case report and literature review JF - World Journal of Gastroenterology N2 - Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging. KW - hemihepatectomy KW - multilocularis KW - Germany KW - Europe KW - liver KW - alveolar echinococcosis KW - echinococcus multilocularis KW - autochthonous infection KW - liver resection Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131525 VL - 19 IS - 26 ER - TY - THES A1 - Guckenberger, Matthias T1 - Analyse des Hitzeschocks bei Neisseria meningitidis mit DNA-Microarrays T1 - Analysis of the heat shock response of Neisseria meningitidis with DNA microarrays N2 - Das Gram negative Bakterium Neisseria meningitidis ist weltweit ein bedeutender Erreger der bakteriellen Meningitis. Obwohl das ausschließlich humanpathogene Bakterium in bis zu 25% der Europäischen Bevölkerung die oberen Atemwege als harmloser Kommensale besiedelt, kommt es unter bestimmten, noch nicht ganz verstandenen Bedingungen zu einer klinisch manifesten Infektion. In dieser Arbeit wurde die neue Technologie der DNA Mikroarray Technologie für die Untersuchung des Transkriptoms bei Neisseria meningitidis etabliert. Untersucht wurde die Reaktion von N. meningitidis auf einen Hitzeschock, eine plötzliche Steigerung der Temperatur. Während einer Infektion wird das Bakterium durch induziertes Fieber sehr ähnlichen Bedingungen ausgesetzt. Im Ergebnis erlaubten die RNA Expressionsanalysen nicht nur eine sichere Unterscheidung deregulierter Gene von Genen mit konstanter Expression, sondern es konnte auch das Ausmaß der Deregulation exakt bestimmt werden. Die Daten der DNA Mikroarray Experimente wurden mit der etablierten Technik der RT-PCR exakt bestätigt. Bei den Hitzeschock-Versuchen mit Neisseria meningitidis konnten zahlreiche ORFs als Hitzeschock-Gene identifiziert werden. Die Funktion dieser Gene, darunter groEL/groES und dnaJ/dnaK, war bereits bei anderen Organismen beschrieben worden, was die Qualität und Reproduzierbarkeit der Ergebnisse unterstreicht. Es konnte gezeigt werden, dass die Intensität des Hitzeschocks und damit die Deregulation der Hitzeschock-Gene mit steigender Temperatur zunimmt. Eine Erklärung für dieses interessante Ergebnis wäre, dass mit Steigerung der Temperatur der Schaden im Bakterium zunimmt und dadurch auch mehr Hitzeschock Proteine zur Reparatur benötigt werden. Daneben wurde erstmals die transkriptionelle Beeinflussung von Genen aus dem Bereich der Transformation durch einen Hitzeschock gefunden. Diese Daten konnten durch einen phänotypischen Nachweis der Verminderung der Transformationsaktivität von Meningokokken nach einem Hitzeschock bestätigt werden. Diese neue Technik wird eine der Schlüsseltechnologien für die Forschung in der postgenomischen Ära sein. Viele Fragen in dem noch lückenhaften Wissen über die Pathologie von Neisseria meningitidis sollen sich in Zukunft mit Hilfe der DNA Mikroarrays beantworten lassen. N2 - The Gram negative bacteria Neisseria meningitidis is a major pathogen of meningitis throughout the world. Although N. meningitidis can be found in the upper airway of up to 30% of European population, it is unclear what exactly causes a clinical infection. Here we established the new technique of DNS microarrays to examine the transcriptional response of N. meningitidis to a rapid increase of temperature, a heat shock. During an infection, the bacteria could encounter similar stress situations when causing high fever. Using rising temperatures from 37oC up to 45oC an increasing number of the 59 selected N. meningitidis ORFs showed dereglulation. Deregulated and not deregulated ORFs were successfully confirmed using semi quantitative RT-PCR. Among these upregulated ORFs there were already known heat shock genes like groEL / groES and dnaJ / dnaK and the alternative sigma factors rpoD and rpoH. These ORFs showed an increasing upregualtion with rising temperatures. An explanation for this interesting result could be that higher temperatures cause more damage to the bacteria and therefore more heat shock proteins are needed for repair. The heat shock response of E. coli has been analysed using whole genome DNS microarrays and these data were in very good concordance with our results. This proofs the excellent quality of the data produced with N. meningitidis DNS microarrays. Besides we found a number of ORFs to be downregulated confronted with high temperatures during heat shock: Mainly ORFs of aerobic and anaerobic metabolism but also ORFs pilM – pilQ. A deregulation after heat shock of these 5 ORFs has not been reported before. These pil ORFs are essential for assembly of type IV pili. Type IV pili are responsible for binding of free DNS, the first step in the process of transformation. A downregulation of these ORFs should be followed be lowered synthesis of type IV pili and therefore decreased transformation activity. As expected, after exposure to a heat shock the transformation activity of Neisseria meningitidis was lowered up to 10% of normal activity. Summarizing, we successfully established the promising technique of DNS microarrays for Neisseria meningitidis, a technique that hopefully will proof as a beneficial tool for examining bacterial pathogenesis and finding new ways of treatment or prevention. KW - Neisseria KW - meningitidis KW - Hitzeschock KW - Microarray KW - Genom KW - Neisseria KW - meningitidis KW - heat KW - shock KW - Microarray Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-8952 ER - TY - THES A1 - Hübner, Claudia T1 - Analyse des Transkriptionsprofils von Neisseria meningitidis während der Infektion von Epithel- und Endothelzellen unter Verwendung der Mikroarraytechnologie T1 - Transcriptome analysis of Neisseria meningitidis during the infection with epithelial and endothelial cells by using microarray technology N2 - Neisseria meningitidis, ein pathogenes Bakterium, das schwere Fälle von Sepsis und Meningitis verursacht, interagiert während der Infektion mit verschiedenen Oberflächen des Wirtes. Die schnellstmögliche Anpassung an die spezifischen Milieubedingungen im Wirtsorganismus ist daher ein essentieller Schritt in der Pathogenese. Durch Verwendung von DNA-Mikroarrays, die auf gespotteten Oligonukleotiden basieren, wurde das Transkriptionsprofil von N. meningitidis während der Infektion von Epithel- und Endothelzellen analysiert. Zur Analyse wurde die isogene kapseldefiziente siaD-Mutante des N. meningitidis Stammes MC58 verwendet. 72 Gene konnten nach Kontakt mit Epithelzellen und 48 Gene nach Kontakt mit Endothelzellen als differential reguliert identifiziert werden. Darunter auch eine große Anzahl von Virulenzgenen. Während ein Teil der detektierten Gene in beiden Systemen als differentiell reguliert galt, gab es doch eine Anzahl von ORF´s, die nur für ein Zellkulturmodell spezifisch reguliert waren (59 spezifische Gene für HEp-2 und 35 spezifische Gene für HBMEC). Für einige ausgewählte Gene wurde die im Mikroarray detektierte Regulierung durch Quantitative RT-PCR nochmals bestätigt. Die Funktion von den als induziert identifizierten Genen rfaF, hem und NMB1843 wurde im Anschluß durch die Konstruktion von Mutanten näher untersucht. Das rfaF-Gen, eine in der LPS Biosynthese involvierte Heptosyl-II-transferase, wurde in beiden Zellkultursystemen als differentiell reguliert identifiziert. Die Deletion des Gens führte speziell für den bekapselten Stamm MC58 zu einer signifikanten Erhöhung der Adhärenz und Invasion nach Infektion von Epithelzellen. Untersuchungen des Infektionspotential für HBMEC Zellen ergaben keine signifikant veränderte Adhärenz und Invasion. Bei zusätzlicher Deletion von rfaF in einem opc negativen Stamm konnte eine Abnahme der bakteriellen Aufnahme im Zellkulturmodell HBMEC beobachtet werden. Dagegen zeigten die opc, rfaF negativen Mutanten nach Kontakt mit HEp-2 Zellen keine verminderte Invasion. Weiterhin führte die Deletion des rfaF-Gens zu einer verstärkten Sensibilität gegenüber humanen Serum. Diese Daten deuten daraufhin, dass die LPS-Struktur eine Rolle in der bakteriellen Zellinteraktion spielt, speziell wenn eine für die Adhäsion wichtige Komponente nicht mehr exprimiert wird. Der ORF NMB1843, der für einen Transkriptionsregulator aus der MarR-Familie kodiert, ebenso wie das Hämolysin Gen konnten nur nach Kontakt mit HBMEC Zellen als differentiell reguliert identifiziert werden. In Infektionsstudien zeigten die hem-Mutanten keine veränderte Adhärenz und Invasion. Weiterhin war die Zytotoxizität der Mutanten nicht eingeschränkt. Ob der ORF NMB1646 daher als Hämolysin fungiert bleibt zu klären. Durchgeführte Mikroarraystudien mit den NMB1843-Mutanten, führten zur Identifizierung einiger ORF´s, die möglicherweise unter der Kontrolle dieses Regulators stehen. Dazu gehören die Virulenz assoziierten Gene sodC, iga und nadA sowie das für ein Hämolysin kodierende Gen NMB1779. Die Untersuchung des Expressionsprofils mittels SDS-PAGE Analyse führte zur Identifizierung einer Proteinbande bei 210 kDa, die spezifisch für die NMB1843 negativen Stämme ist. Dieses Protein wurde als nadA identifiziert. NadA induziert im Tiermodell bakterizide Antikörper und gilt daher als möglicher Impfstoffkandidat. Die in dieser Arbeit vorgelegten Daten liefern neue Einblicke in die Pathogenitätsmechanismen von N. meningitidis und belegen die Bedeutung der transkriptionellen Genregulation in den einzelnen Stadien der Meningokokkeninfektion. N2 - Neisseria meningitidis is a major cause of septicemia and meningitis. During the course of infection, N. meningitidis encounters multiple environments within its host, which makes rapid adaptation to environmental changes a crucial factor for neisserial pathogenicity. As technology platform oligonucleotide-based DNA microarrays were employed to analyse the transcriptome profile of N. meningitidis during two key steps of meningococcal infection: the interaction with epithelial and endothelial cells. The isogenic capsule deficient siaD mutant of the N. meningitidis strain MC58 was used for this study. Seventy-two genes were differentially regulated after contact with epithelial cells, and 48 genes were differentially regulated after contact with endothelial cells, including a considerable proportion of well-known virulence genes. While several genes were in concordance between bacteria adherent to both cell types, there were a considerable number of open reading frames that were differentially regulated in only one system (59 genes specific for HEp-2 and 35 genes specific for HBMEC). Quantitative RT-PCR analyses confirmed the microarray observed regulation for several selected ORF´s. Subsequently, the function of the upregulated genes rfaF, hem and NMB1843 was investigated by construction of mutants. The rfaF gene, encoding a heptosyl-2-transferase involved in LPS biosynthesis, were detected as being differentially regulated in both cell systems. Disruption of the rfaF gene in meningococcal strain MC58 resulted in a significantly increased adhesion and invasion to epithelial cells in particular for the capsulated mutant. Investigations of the infection potential for HBMEC cells did not result in a significant change in adherence and invasion pattern. The additional deletion of the rfaF gene in an opc negative strain leads to a significantly decrease in the bacterial uptake for HBMEC cells. Compared to HBMEC, opc, rfaF mutants showed no differences in internalisation after contact with HEp-2 cells. Moreover rfaF deficient meningococci demonstrated enhanced sensitivity to normal human serum (NHS). These data provide evidence that the LPS structure plays a role in the bacterial cell interaction, particularly if an important adhaesive structure is absent. The ORF NMB1843, which encodes a transcriptional regulator of the MarR family, as well the hemolysin gene, were detected as being upregulated only after contact with endothelial cells. Using infection assays, no changes were detected in the adherence and invasion pattern for hem mutants. Furthermore the cytotoxic potential of the mutants was not different from the parental strains. Therefore it remains to be clarified whether the ORF NMB1646 actually act as a hemolysin. Microarray studies for the NMB1843 mutants showed some ORF´s, which possibly are under control of this regulator, for example the virulence genes sodC, iga and nadA as well as the hemolysin coding gene NMB1779. The analysis of the expression profile by SDS-PAGE led to the identification of a 210 kDa protein, which is specific for the NMB1843 negative strains. This unknown protein was identified as nadA. NadA evokes a strong antibactericidal antibody response in laboratory animals. For this reason NadA is regarded as a good vaccine candidate. The data represented in this study provide new insight into the pathogenicity mechanisms of N. meningitidis and could demonstrate the importance of gene regulation on the trancriptional level during different stages of meningococcal infection. KW - Neisseria meningitidis KW - Infektion KW - Endothel KW - Epithel KW - Transkription KW - Neisseria meningitidis KW - Adhärenz und Invasion KW - Epithel und Endothelzellen KW - Transkriptionsprofil KW - Neisseria meningitidis KW - adhesion and invasion KW - epithelial and endothelial cells KW - Transcriptome Analysis Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-13535 ER - TY - THES A1 - Kurz, Sebastian Gerhard T1 - Analyse des Transkriptoms von Neisseria meningitidis Serogruppe B mit DNA-Microarrays T1 - Transcriptome Analysis of Neisseria meningitidis Serogroup B with DNA Microarrays N2 - Die Anwendbarkeit eines Oligonukleotid-basierten Microarray-Systems zur Transkriptomanalyse von Neisserie meningitidis Serogruppe B wurde im Vergleich mit einem cDNA-basierten System demonstriert. Hierzu wurde für ein Subset von 60 Genen die Eigenschaften anhand von Parallelhybridisierungen sowie eines vormals etablierten Hitzeschock Modells untersucht. Aufgrund der Vergleichsdaten wurde ein Gesamtgenmom-Array auf Oligonukleotidbasis etabliert und zur Analyse der Hitzeschock-Reaktion verwendet. Schließlich wurde mit diesem Array-System ein Modell zur Untersuchung der Transkriptomänderung nach Konfrontation mit humanem Serum realisiert. Insgesamt zeigten 284 Gene (13% des Genoms) eine differentielle Regulation mit ebenmäßigem Verhältnis von Hoch- und Herunterregulation. Die Anwendbarkeit im Hinblick auf die Suche nach potentiellen Vakzinekandidaten wurde diskutiert. N2 - Oligonucleotide- and cDNA-based microarrays comprising a subset of 60 genes were assessed for transcriptome analysis of Neisseria meningitidis. Study of the heat shock response as well as hybridization with identical probes revealed similar performances for both systems. Oligonucleotide-based arrays encompassing the entire genome were implemented using the heat shock model. Subsequently a model for investigation of the transcriptional response of Neisseria meningitidis after challenge with human serum was established. 284 genes showed differential regulation with a balanced proportion of up- and donwregulated genes, accounting for 13% of the entire genome. The suitability of such a system for the identification of potential vaccine candidates was discussed. KW - Neisserien KW - DNA-Microarrays KW - Transkriptom KW - Hitzeschock KW - Impfstoffentwicklung KW - Neisseria KW - DNA microarrays KW - Transcriptome KW - Heat shock KW - Vaccinology Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-13845 ER - TY - JOUR A1 - Brehm, Klaus A1 - Koziol, Uriel A1 - Krohne, Georg T1 - Anatomy and development of the larval nervous system in Echinococcus multilocularis JF - Frontiers in Zoology N2 - Background The metacestode larva of Echinococcus multilocularis (Cestoda: Taeniidae) develops in the liver of intermediate hosts (typically rodents, or accidentally in humans) as a labyrinth of interconnected cysts that infiltrate the host tissue, causing the disease alveolar echinococcosis. Within the cysts, protoscoleces (the infective stage for the definitive canid host) arise by asexual multiplication. These consist of a scolex similar to that of the adult, invaginated within a small posterior body. Despite the importance of alveolar echinococcosis for human health, relatively little is known about the basic biology, anatomy and development of E. multilocularis larvae, particularly with regard to their nervous system. Results We describe the existence of a subtegumental nerve net in the metacestode cysts, which is immunoreactive for acetylated tubulin-α and contains small populations of nerve cells that are labeled by antibodies raised against several invertebrate neuropeptides. However, no evidence was found for the existence of cholinergic or serotoninergic elements in the cyst wall. Muscle fibers occur without any specific arrangement in the subtegumental layer, and accumulate during the invaginations of the cyst wall that form brood capsules, where protoscoleces develop. The nervous system of the protoscolex develops independently of that of the metacestode cyst, with an antero-posterior developmental gradient. The combination of antibodies against several nervous system markers resulted in a detailed description of the protoscolex nervous system, which is remarkably complex and already similar to that of the adult worm. Conclusions We provide evidence for the first time of the existence of a nervous system in the metacestode cyst wall, which is remarkable given the lack of motility of this larval stage, and the lack of serotoninergic and cholinergic elements. We propose that it could function as a neuroendocrine system, derived from the nervous system present in the bladder tissue of other taeniids. The detailed description of the development and anatomy of the protoscolex neuromuscular system is a necessary first step toward the understanding of the developmental mechanisms operating in these peculiar larval stages. KW - Echinococcus KW - Metacestode KW - Protoscolex KW - Nervous system KW - Neuropeptide KW - Serotonin KW - Acetylated tubulin Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96504 UR - http://www.frontiersinzoology.com/content/10/1/24 ER - TY - JOUR A1 - Becam, Jérôme A1 - Walter, Tim A1 - Burgert, Anne A1 - Schlegel, Jan A1 - Sauer, Markus A1 - Seibel, Jürgen A1 - Schubert-Unkmeir, Alexandra T1 - Antibacterial activity of ceramide and ceramide analogs against pathogenic Neisseria JF - Scientific Reports N2 - Certain fatty acids and sphingoid bases found at mucosal surfaces are known to have antibacterial activity and are thought to play a more direct role in innate immunity against bacterial infections. Herein, we analysed the antibacterial activity of sphingolipids, including the sphingoid base sphingosine as well as short-chain C\(_{6}\) and long-chain C\(_{16}\)-ceramides and azido-functionalized ceramide analogs against pathogenic Neisseriae. Determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) demonstrated that short-chain ceramides and a ω-azido-functionalized C\(_{6}\)-ceramide were active against Neisseria meningitidis and N. gonorrhoeae, whereas they were inactive against Escherichia coli and Staphylococcus aureus. Kinetic assays showed that killing of N. meningitidis occurred within 2 h with ω–azido-C\(_{6}\)-ceramide at 1 X the MIC. Of note, at a bactericidal concentration, ω–azido-C\(_{6}\)-ceramide had no significant toxic effect on host cells. Moreover, lipid uptake and localization was studied by flow cytometry and confocal laser scanning microscopy (CLSM) and revealed a rapid uptake by bacteria within 5 min. CLSM and super-resolution fluorescence imaging by direct stochastic optical reconstruction microscopy demonstrated homogeneous distribution of ceramide analogs in the bacterial membrane. Taken together, these data demonstrate the potent bactericidal activity of sphingosine and synthetic short-chain ceramide analogs against pathogenic Neisseriae. KW - ceramide analogs KW - Neisseria KW - ceramide Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159367 VL - 7 ER - TY - JOUR A1 - Strobel, Lea A1 - Johswich, Kay O. T1 - Anticoagulants impact on innate immune responses and bacterial survival in whole blood models of Neisseria meningitidis infection JF - Scientific Reports N2 - Neisseria meningitidis (meningococcus) causes invasive diseases such as meningitis or septicaemia. Ex vivo infection of human whole blood is a valuable tool to study meningococcal virulence factors and the host innate immune responses. In order to consider effects of cellular mediators, the coagulation cascade must be inhibited to avoid clotting. There is considerable variation in the anticoagulants used among studies of N. meningitidis whole blood infections, featuring citrate, heparin or derivatives of hirudin, a polypeptide from leech saliva. Here, we compare the influence of these three different anticoagulants, and additionally Mg/EGTA, on host innate immune responses as well as on viability of N. meningitidis strains isolated from healthy carriers and disease cases, reflecting different sequence types and capsule phenotypes. We found that the anticoagulants significantly impact on cellular responses and, strain-dependently, also on bacterial survival. Hirudin does not inhibit complement and is therefore superior over the other anticoagulants; indeed hirudin-plasma most closely reflects the characteristics of serum during N. meningitidis infection. We further demonstrate the impact of heparin on complement activation on N. meningitidis and its consequences on meningococcal survival in immune sera, which appears to be independent of the heparin binding antigens Opc and NHBA. KW - infection KW - pathogens KW - Neisseria meningitidis KW - anticoagulants Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176226 VL - 8 IS - 10225 ER - TY - JOUR A1 - Moremi, Nyambura A1 - Claus, Heike A1 - Mshana, Stephen E. T1 - Antimicrobial resistance pattern: a report of microbiological cultures at a tertiary hospital in Tanzania JF - BMC Infectious Diseases N2 - Background Antimicrobial resistance has been declared by the World Health Organization as a threat to the public health. The aim of this study was to analyze antimicrobial resistance patterns of the common pathogens occurring at the Bugando Medical Centre (BMC), Mwanza, Tanzania to provide data for antimicrobial stewardship programmes. Methods A total of 3330 microbiological culture results scripts representing non-repetitive specimens reported between June 2013 and May 2015 were retrieved and analyzed for pathogens and their susceptibility patterns using STATA-11 software. Results Out of 3330 specimens, 439 (13.2%) had positive culture. Staphylococcus aureus (n = 100; 22.8%), Klebsiella pneumoniae (n = 65; 14.8%) and Escherichia coli (n = 41; 9.3%) were the most frequently isolated bacteria. Of 78 Staphylococcus aureus tested, 27 (34.6%) were found to be methicillin resistant Staphylococcus aureus (MRSA). Rates of resistance of Klebsiella pneumoniae and Escherichia coli isolates to third generation cephalosporins were 38.5% (25/65) and 29.3% (12/41) respectively. Staphylococcus aureus and Klesbiella pneumoniae were commonly isolated from bloodstream infections while Escherichia coli and Pseudomonas aeruginosa were the predominant isolates from urinary tract and wounds infections respectively. Of 23 Salmonella species isolated, 22 (95%) were recovered from the blood. Nine of the 23 Salmonella species isolates (39%) were found to be resistant to third generation cephalosporins. The resistance rate of gram-negative bacteria to third generation cephalosporins increased from 26.5% in 2014 to 57.9% in 2015 (p = 0.004) while the rate of MRSA decreased from 41.2% in 2013 to 9.5% in 2015 (p = 0.016). Multidrug-resistant gram-negative isolates were commonly isolated from Intensive Care Units and it was noted that, the majority of invasive infections were due to gram-negative bacteria. Conclusion There is an increase in proportion of gram-negative isolates resistant to third generation cephalosporins. The diversity of potential pathogens resistant to commonly prescribed antibiotics underscores the importance of sustained and standardized antimicrobial resistance surveillance and antibiotic stewardship programmes in developing countries. KW - Tanzania KW - antimicrobial resistance KW - cephalosporin-resistant gram-negative bacteria KW - MRSA Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161185 VL - 16 IS - 756 ER - TY - JOUR A1 - Marincola, Gabriella A1 - Liong, Olivia A1 - Schoen, Christoph A1 - Abouelfetouh, Alaa A1 - Hamdy, Aisha A1 - Wencker, Freya D. R. A1 - Marciniak, Tessa A1 - Becker, Karsten A1 - Köck, Robin A1 - Ziebuhr, Wilma T1 - Antimicrobial Resistance Profiles of Coagulase-Negative Staphylococci in Community-Based Healthy Individuals in Germany JF - Frontiers in Public Health N2 - Coagulase-negative staphylococci (CoNS) are common opportunistic pathogens, but also ubiquitous human and animal commensals. Infection-associated CoNS from healthcare environments are typically characterized by pronounced antimicrobial resistance (AMR) including both methicillin- and multidrug-resistant isolates. Less is known about AMR patterns of CoNS colonizing the general population. Here we report on AMR in commensal CoNS recovered from 117 non-hospitalized volunteers in a region of Germany with a high livestock density. Among the 69 individuals colonized with CoNS, 29 had reported contacts to either companion or farm animals. CoNS were selectively cultivated from nasal swabs, followed by species definition by 16S rDNA sequencing and routine antibiotic susceptibility testing. Isolates displaying phenotypic AMR were further tested by PCR for presence of selected AMR genes. A total of 127 CoNS were isolated and Staphylococcus epidermidis (75%) was the most common CoNS species identified. Nine isolates (7%) were methicillin-resistant (MR) and carried the mecA gene, with seven individuals (10%) being colonized with at least one MR-CoNS isolate. While resistance against gentamicin, phenicols and spectinomycin was rare, high resistance rates were found against tetracycline (39%), erythromycin (33%) and fusidic acid (24%). In the majority of isolates, phenotypic resistance could be associated with corresponding AMR gene detection. Multidrug-resistance (MDR) was observed in 23% (29/127) of the isolates, with 33% (23/69) of the individuals being colonized with MDR-CoNS. The combined data suggest that MR- and MDR-CoNS are present in the community, with previous animal contact not significantly influencing the risk of becoming colonized with such isolates. KW - coagulase-negative staphylococci KW - antimicrobial resistance KW - One Health KW - community settings KW - Germany Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240881 SN - 2296-2565 VL - 9 ER - TY - THES A1 - Ebner, Sebastian Manfred T1 - Antimykotikaresistenzen bei deutschen \(Candida\) \(auris\) Isolaten T1 - Antimycotic resistance in German \(Candida\) \(auris\) isolates N2 - Bei dem 2009 erstbeschriebenen Hefepilz C. auris handelt es sich um einen Keim, welcher aufgrund von nosokomialen Ausbrüchen und hohen Antimykotikaresistenzen Aufmerksamkeit erregte. Ziel dieser Arbeit war es in Deutschland gesammelte Isolate bezüglich vorhandener Resistenzen und Mutationen in Resistenzregionen zu testen und das epidemiologische Geschehen hierzulande mit dem globalen Auftreten des Keims zu vergleichen. Bezüglich der durchgeführten Resistenztestungen wiesen die CLSI-konformen Testarten (YO-Platten und E-Test-Verfahren) meist vergleichbare Ergebnisse auf. Für das EUCAST-konforme Mikrodilutionstestverfahren kann aufgrund eines stark ausgeprägten paradoxen Wachstumseffekts nur Anidulafungin, nicht jedoch Caspofungin, zur Testung empfohlen werden. Insgesamt erwiesen sich 25 % der Isolate als Caspofungin-resistent. Zwei Isolate zeigten eine Resistenz gegenüber allen getesteten Echinocandinen (16,7 %). Die höchsten Resistenzraten wurden gegenüber Fluconazol (92 %) beobachtet. Zwei der Isolate zeigten sich gegenüber Voriconazol resistent (16,7 %). Für Amphotericin B konnte eine Resistenzrate von 33,3 % festgestellt werden. Für die Wirkstoffe Posaconazol und Itraconazol erwiesen sich alle untersuchten Isolate als sensitiv. Dies konnte auch mit Ausnahme eines Isolates für 5-Flucytosin beobachtet werden. Die durch eine Sanger-Sequenzierung erhaltenen Sequenzen der Gene FKS1 und ERG11 wurden auf Mutationen untersucht, welche zu Aminosäuresubstitutionen im Gesamtprotein führten. Hierbei ergaben sich für zwei Isolate (16,7 %) Mutationen im FKS1-Hot Spot 1 (Typ S639F und S639Y). Beide Isolate zeigten sich in den AFST Echinocandin-resistent. Bei allen untersuchten Isolaten lagen Mutationen im ERG11 Gen vor. So fand sich in 8 Fällen eine Mutation des Typen Y132F (66,7 %), in 3 Fällen der Typ K143R (25 %) und in einem Fall der Typ F126L (8,3 %). Im Rahmen eines anderen Projekts wurde mit den hier gewonnenen PCR-Produkten ein WGS durchgeführt, um die Isolate durch SNPs-Vergleich mit Referenzstämmen phylogenetischen Clades zuzuordnen. Dabei konnten 91,7 % der Isolate dem südasiatischen Clade I und ein Isolat dem südafrikanischen Clade III zugeordnet werden. Aufgrund der geringen epidemiologischen Fallzahlen in Deutschland scheint gegenwärtig keine Bedrohung von C. auris auszugehen. Berichte aus anderen Ländern konnten allerdings eine rasche, ausbruchartige Zunahme von C. auris Fällen nachweisen. So kann nur angeraten werden das infektiologische Geschehen in Deutschland weiterhin zu beobachten. N2 - The fungus C. auris was first described in the year 2009. Because of a high number of nosocomial outbrakes and high antimycotic resistance rates the fungus attracted great media attention. The aim of this dissertion was to test German isolates for antimycotic resistance and mutations in resistance genes. Additionally, the epidemiological occurrence in Germany was compared to the global outspread. In this context CLSI-conform methods for resistance testing (YO-Plates and E-Test-Plates) generated comparable results. The testing of EUCAST-conform microdilution plates showed a strong paradoxical growth for Caspofungin. Because of this only Anidulafungin can be recommended for testing. In summary 25 % of the isolates were resistant against Caspofungin. Two isolates showed resistance against all tested Echinocandines (16,7 %). The highest rates were detected for Fluconazol (92 %). Furthermore, two of the isolates (16,7 %) showed resistance against Voriconazol. There was a resistance rate of 33,3 % to Amphotericin B. No isolate showed resistance against Posaconazol or Itraconazol. And only one isolate was resistant against 5-Flucytosin. Sanger-Sequencing was used to detect mutations in resistance genes FKS1 und ERG11, which could lead to a substitution of amino acids in the protein. There were two isolates (16,7 %) with mutations in FKS1-Hot Spot 1 (type S639F and S639Y). Both isolates showed a Echinocandin resistance in AFST. All tested isolates showed a mutation in ERG11. There were eight cases of type Y132F (66,7 %), three cases of K143R (25 %) and in one case type F126L (8,3 %). The PCR products of this study were used in a different project for WSG. This made it possible to group the isolates into phylogenetic clades. In summary 91,7 % of the isolates were related to Clade I (South Asia) and one isolate was related to Clade III (South Africa). Because of low epidemiologic occurence in Germany, there is little threat of servere health care issues at the moment. Reports from diffferent countries all over the world however, showed a quick, outbrake-like increase of C. auris cases. Therefore, further observation of German epidemiology is highly recommended. KW - Candida KW - Resistenz KW - Wirkstoff KW - Behandlung KW - Antimykotikaresistenz KW - Candida auris KW - Resistance mechanism C. auris KW - Mutation FKS Hot Spot 1/ERG11 KW - Nosokomiale Infektion KW - E-Test KW - Mikrodilutionstest KW - Hospitalismus KW - Pilz Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318068 ER - TY - JOUR A1 - Tappe, Dennis A1 - Haeupler, Alexandra A1 - Schäfer, Hansjörg A1 - Racz, Paul A1 - Cramer, Jakob P. A1 - Poppert, Sven T1 - Armillifer armillatus Pentastomiasis in African Immigrant, Germany JF - Emerging Infectious Diseases N2 - No abstract available. Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129054 N1 - Public Domain (Source: http://wwwnc.cdc.gov/eid/page/copyright-and-disclaimers) VL - 19 IS - 3 ER - TY - JOUR A1 - Drayß, Maria A1 - Claus, Heike A1 - Hubert, Kerstin A1 - Thiel, Katrin A1 - Berger, Anja A1 - Sing, Andreas A1 - van der Linden, Mark A1 - Vogel, Ulrich A1 - Lâm, Thiên-Trí T1 - Asymptomatic carriage of Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, Group A Streptococcus and Staphylococcus aureus among adults aged 65 years and older JF - PLoS ONE N2 - Objective The aim of this study was to determine the prevalence of Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, group A Streptococcus (GAS), and Staphylococcus aureus in asymptomatic elderly people and to unravel risk factors leading to colonization. Methods A multi-centre cross-sectional study was conducted including 677 asymptomatic adults aged 65 years or more, living at home or in nursing homes. Study areas were Greater Aachen (North-Rhine-Westphalia) and Wuerzburg (Bavaria), both regions with medium to high population density. Nasal and oropharyngeal swabs as well as questionnaires were collected from October 2012 to May 2013. Statistical analysis included multiple logistic regression models. Results The carriage rate was 1.9% ([95%CI: 1.0–3.3%]; 13/677) for H. influenzae, 0.3% ([95%CI: 0–1.1%]; 2/677) for N. meningitidis and 0% ([95% CI: 0–0.5%]; 0/677) for S. pneumoniae and GAS. Staphylococcus aureus was harboured by 28.5% of the individuals ([95% CI: 25.1–32.1%]; 193/677) and 0.7% ([95% CI: 0.2–1.7%]; 5/677) were positive for methicillin-resistant S. aureus. Among elderly community-dwellers colonization with S. aureus was significantly associated with higher educational level (adjusted OR: 1.905 [95% CI: 1.248–2.908]; p = 0.003). Among nursing home residents colonization was associated with being married (adjusted OR: 3.367 [1.502–7.546]; p = 0.003). Conclusion The prevalence of N. meningitidis, H. influenzae, S. pneumoniae and GAS was low among older people in Germany. The S. aureus rate was expectedly high, while MRSA was found in less than 1% of the individuals. KW - Geriatric care KW - Geriatrics KW - Elderly KW - Staphylococcus aureus KW - Nursing homes KW - Haemophilus influenzae KW - Neisseria meningitidis KW - Methicillin-resistant Staphylococcus aureus Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201042 VL - 14 IS - 2 ER - TY - THES A1 - Drayß, Maria T1 - Asymptomatisches Trägertum von Staphylococcus aureus und Haemophilus influenzae bei Senioren T1 - Asymptomatic carriage of Staphylococcus aureus and Haemophilus influenzae in elderly people N2 - Ältere Menschen sind gegenüber invasiven Infektionen und Sepsis besonders vulnerabel mit ungünstiger Prognose. Staphylococcus aureus und Haemophilus influenzae können beide invasive Infektionen verursachen. Oft geht eine asymptomatische Besiedelung einer Infektion voraus und ist ein Risikofaktor für eine invasive Infektion. Daher wurde eine bizentrische Querschnittstudie in den Regionen Aachen und Würzburg durchgeführt, um die Prävalenz von H. influenzae, S. aureus und MRSA (Methicillin resistenter S. aureus) bei asymptomatischen Senioren zu bestimmen, wie auch Risikofaktoren für eine Besiedelung. Von Oktober 2012 bis Mai 2013 wurden 677 Erwachsenen im Alter von 65 Jahren oder älter eingeschlossen, die zu Hause oder in Seniorenheimen lebten. Die Prävalenz von H. influenzae bei älteren Menschen war mit einer Trägerrate von nur 1,9% ([95% CI: 1,0 - 3,3%]; 13/677) sehr niedrig. Trägerisolate waren überwiegend nicht typisierbare H. influenzae, zeigten eine hohe clonale Diversität und waren alle Ampicillin-sensibel. Die Prävalenz von S. aureus war mit 28,5% ([95% CI: 25,1 - 32,1%]; 193/677) hoch, wie für die deutsche Allgemeinbevölkerung bekannt, während MRSA bei weniger als 1% der Teilnehmer gefunden wurde (0,7% [95% CI: 0,2 - 1,7%]; 5/677). Die Prävalenz von H. influenzae, S. aureus und MRSA unterschied sich nicht signifikant zwischen selbständig zu Hause lebenden Senioren und Pflegeheimbewohnern. Ältere, selbständig lebende Menschen mit höherem Bildungsniveau hatten signifikant höhere Kolonisierungsraten mit S. aureus (adjusted OR: 1,905 [95% CI: 1,248 - 2,908]; p = 0,003). Bei Pflegeheimbewohnern war eine Kolonisierung signifikant mit Verheiratet sein assoziiert (adjusted OR: 3,367 [95% CI: 1,502 - 7,546]; p = 0,003). Diese Ergebnisse unterstreichen die Bedeutung von sozio-demographischen Faktoren für eine Kolonisierung mit S. aureus und schließen eine Lücke bei epidemiologischen Daten zu H. influenzae. N2 - Elderly people are especially vulnerable to invasive infections and sepsis with often poor outcome. Staphyloccus aureus and Haemophilus influenzae both can cause invasive infections. Asymptomatic colonization often precedes infection and poses a risk for invasive infection. Therefore, a bi-centric cross-sectional carrier study was conducted in the regions of Aachen and Wuerzburg, Germany, to determine the prevalence of H. influenzae, S. aureus and MRSA (methicillin resistant S. aureus) in asymptomatic elderly people and to identify risk factors for colonization. From October 2012 to May 2013 677 adults aged 65 years and older were included, living at home or in nursing homes. In contrast to children and younger adults the prevalence of H. influenzae was very low among elderly people with a carriage rate of only 1.9% ([95% CI: 1.0 - 3.3%]; 13/677). Carrier isolates were predominantly non typeable H. influenzae, showed a high clonal diversity and were all susceptible to ampicillin. The prevalence of S. aureus was expectedly high as known for the German general population (28.5% [95% CI: 25.1 - 32.1%]; 193/677), while MRSA was found in less than 1% of the individuals (0.7% [95% CI: 0.2 - 1.7%]; 5/677). The prevalence of H. influenzae, S. aureus und MRSA did not differ significantly between community dwellers and nursing home residents. Elderly community-dwellers with higher education level had significantly higher colonization rates with S. aureus (adjusted OR: 1.905 [95% CI: 1.248 - 2.908]; p = 0.003). Among nursing home residents, colonization was significantly associated with being married (adjusted OR: 3.367 [1.502 - 7.546]; p = 0.003). These results underline the importance of socio-demographic factors for colonization with S. aureus and close a gap in epidemiological data on H. influenzae. KW - Staphylococcus aureus KW - Haemophilus influenzae KW - MRSA KW - Senioren KW - Besiedelung KW - Multilocus-Sequenz-Typisierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-272276 ER - TY - THES A1 - Stieber, Hanna T1 - Auswirkungen des Sphingolipidsynthese-Inhibitors Myriocin auf Vitalität und Antimykotikaresistenz von \(Candida\) \(auris\) T1 - Impact of the sphingolipid synthesis inhibitor myriocin on viability and antifungal susceptibility of \(Candida\) \(auris\) N2 - Candida Spezies gehören als kommensale Organismen zur normalen menschlichen Mikroflora, können allerdings unter bestimmten Bedingungen Krankheitswert erlangen. Limitationen in der Behandlung durch immer mehr resistente Candida Spezies und die wachsende Zahl immunsupprimierter Patienten gelten als Hauptursachen für die steigende Häufigkeit invasiver Candidosen und systemischer Candidämien. Die 2009 entdeckte Spezies C. auris stellt durch ihre zahlreichen Resistenzen, das Potential zur Auslösung nosokomialer Ausbrüche in Krankenhäusern und die schnelle Verbreitung über mehrere Kontinente eine neue Herausforderung dar. Der Bedarf an neuen Antimykotika mit anderen Wirkmechanismen und neuen Zielstrukturen ist größer denn je. Die fungale Sphingolipid-Biosynthese wurde bereits mehrfach als potenzielles Ziel antimykotischer Therapie diskutiert, allerdings bezieht sich die meiste Forschung hierzu auf C. albicans]. In vorliegender Arbeit wurden die Auswirkungen der Inhibition der Sphingolipid Biosynthese durch Myriocin auf C. auris und sein Resistenzverhalten untersucht und mit denen auf andere Candida Spezies verglichen. Sowohl die Mikrodilution als auch die Plattentropftests zeigten, dass C. auris verglichen mit anderen Candida Spezies besonders sensitiv auf die Anwesenheit von Myriocin reagierte und stärker im Wachstum gehemmt wurde. Der Survival Assay ergab für alle drei Spezies ein Absenken der CFU durch Myriocin, die Abweichungen zwischen den Stämmen waren jedoch unwesentlich. Unterschiede konnten in Vitalität und Vermehrung der verschiedenen Spezies unter Myriocineinfluss festgestellt werden. Aus der Lebend/Tot-Färbung ging hervor, dass Myriocin bei allen Stämmen zum Absterben von Candida Zellen führte, C. albicans und C. glabrata allerdings signifikant niedrigere Überlebensraten im Vergleich zu den C. auris Isolaten aufwiesen. Im Gegensatz dazu konnte mithilfe der FITC-Mikroskopie gezeigt werden, dass Candida Zellen unter Zugabe von Myriocin weniger Tochterzellen ausbildeten, was auf eine erschwerte oder zumindest verlangsamte Zellvermehrung hindeutet. Dabei schien das Wachstum der C. auris Stämme durch Myriocin deutlich eingeschränkter zu sein als das von C. albicans und C. glabrata. Durch weitere Mikroskopie und die Kombination aus Lebend/Tot Färbung mittels PI und FITC Färbung, sollte die Verteilung der toten Zellen auf Mutter- und Tochterzellen evaluiert werden. Hier konnte ein Trend zu einem vermehrten Zellsterben der Tochterzellen, vor allem für C. auris, festgestellt werden. Abschließende E-Tests für Amphotericin B, Anidulafungin und Fluconazol ergaben eine signifikante Herabsetzung der MHK für alle C. auris Isolate durch Myriocin. Die hier vorgestellten Ergebnisse und die durch mehrere Studien festgestellten Differenzen in der Sphingolipidkomposition von C. auris verglichen mit anderen Candida Spezies geben Hinweis darauf, dass Sphingolipide für Vitalität, Zellteilung und vor allem für die Wirkung einiger Antimykotika auf C. auris eine besondere, wenn nicht übergestellte Bedeutung haben könnten. Zwar wurde die Sphingolipidsynthese bereits mehrfach als potenzieller Angriffspunkt für die antifungale Therapie diskutiert, allerdings lediglich am Beispiel anderer Candida Spezies. Der Sphingolipidstoffwechsel könnte somit ein vielversprechender Ansatz für die Behandlung des sonst so therapieresistenten und lebensbedrohlichen Pilzes C. auris sein. N2 - Candida species are commensal organisms belonging to the normal human microflora, but can become pathogenic under certain conditions. Limitations in treatment due to an increasing number of resistant Candida species and the growing number of immunosuppressed patients are considered to be the main reasons for the increasing frequency of invasive candidiasis and systemic candidemia. C. auris, a species discovered in 2009, shows potential to cause nosocomial outbreaks in hospitals, limited susceptibility to numerous antifungals and a rapid spread across several continents. This leads to a need for new antifungal agents with different mechanisms of action and new targets. Fungal sphingolipid biosynthesis has been discussed several times as a potential target of antifungal therapy, however most research on this relates to C. albicans. In the present work, the effects of inhibition of sphingolipid biosynthesis by myriocin on C. auris and its impact on fungal susceptibility were investigated and compared with those on other Candida species. Both microdilution and plate droplet assays showed that C. auris was more sensitive to myriocin compared with other Candida species and showed severe growth defects. The survival assay showed a lowering of CFU by myriocin for all three species, but the differences between the strains were insignificant. Live/dead staining showed that myriocin led to the death of Candida cells in all strains, but C. albicans and C. glabrata had significantly lower survival rates compared to the C. auris isolates. In contrast, FITC microscopy showed that Candida cells produced fewer daughter cells when myriocin was added, indicating that cell proliferation was impeded or at least slowed. In this regard, the growth of C. auris strains appeared to be significantly more restricted by myriocin than that of C. albicans and C. glabrata. Further microscopy and the combination of live/dead staining using PI and FITC staining, was performed to evaluate the distribution of dead cells between mother and daughter cells. Here, a trend towards increased cell death of daughter cells, especially for C. auris, was observed. Final E-tests for amphotericin B, anidulafungin, and fluconazole revealed a significant reduction in MIC for all C. auris isolates by myriocin. These results and the differences in sphingolipid composition of C. auris compared with other Candida species established by several studies provide evidence that sphingolipids may have a special, if not superimposed, importance for viability, cell division, and especially for the suscteptibility of C. auris to some antifungals. It is true that sphingolipid synthesis has been discussed several times as a potential target for antifungal therapy, but only using other Candida species as examples. Sphingolipid metabolism could thus be a promising approach for the treatment of the therapy-resistant and life-threatening fungus C. auris. KW - Candida KW - Sphingolipide KW - Sphingolipidstoffwechsel KW - Multiresistenz KW - pathogene Pilze KW - Candida auris KW - Antimykotikaresistenz KW - antifungal susceptibility KW - myriocin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-289121 ER - TY - THES A1 - Isberner, Nora T1 - Auswirkungen von Staphylococcus aureus auf die Endothelpermeabilität in Ea.hy926-Zellen T1 - Influence of Staphylococcus aureus on endothelial permeability in Ea.hy926 cells N2 - Staphylococcus aureus (S. aureus) ist einer der häufigsten Erreger schwerer endovaskulärer Infektionen, die häufig mit einer Dissemination des Erregers in andere Organe und lebensbedrohlichen Komplikationen wie Endokarditis, Osteomyelitis oder Abszessen assoziiert sind. Entscheidender Schritt in der Pathogenese endovaskulärer Infektionen ist die Schädigung und Überwindung der Endothelbarriere. Für deren Integrität ist die Intaktheit von Zell-Zell-Verbindungen elementar, diese werden unter anderem durch Src-Kinasen reguliert. Es ist bekannt, dass S. aureus Fibronektin-Bindeproteine (FnBPs) maßgeblich für die Adhärenz und Invasion des Erregers in Endothelzellen sind. Die Invasion erfolgt über eine indirekte Bindung an α5β1-Integrine, invasive Eigenschaften finden sich in nahezu allen klinischen Isolaten. In verschiedenen Tiermodellen konnte außerdem ein Zusammenhang zwischen der Expression von FnBPs und der Dissemination von S. aureus in andere Organe gezeigt werden. Bislang ist jedoch nicht untersucht, welche Auswirkung die S. aureus-Infektion auf die Endothelbarriere hat und welche Mechanismen für die Translokation des Erregers verantwortlich sind. In dieser Arbeit wurde analysiert, ob die Infektion mit S. aureus- und S. carnosus-Stämmen in vitro zu einer Schädigung der endothelialen Integrität von EA.hy926-Zellen führt. Hierzu wurden Änderungen der transendothelialen Impedanz und der Endothelpermeabeabilität nach Infektion im xCELLigence- bzw. Transwell-System erfasst. Zytotoxische Effekte wurden durch Kristallviolettfärbungen, immunfluoreszenz-mikroskopische Untersuchungen der Mitochondrien und Nuklei sowie die Erfassung der hypodiploiden Zellkerne mittels Durchflusszytometrie quantifiziert. Zur Entschlüsselung des molekularen Mechanismus wurden Veränderungen der Adherens und Tight Junction-Proteine ZO-1 und VE-Cadherin in der Immunfluoreszenz untersucht. Die Rolle von Src-Kinasen wurde durch pharmakologische Inhibition analysiert. Es konnte gezeigt werden, dass FnBP-exprimierende S. aureus-Stämme eine Abnahme der transendothelialen Impedanz verursachen und dass es 4 und 24 Stunden nach Infektion zu einer signifikanten Zunahme der Endothelpermeabilität kommt. Zytotoxische Effekte auf die Endothelzellen durch die Infektion traten nach 24 Stunden auf, jedoch nicht nach 4 Stunden. VE-Cadherin und ZO-1 zeigten 4 Stunden nach Infektion eine FnBP-abhängige Konformationsänderung und Reduktion der Signalintensität. Außerdem konnte demonstriert werden, dass die Inhibition von Src-Kinasen den Anstieg der Endothelpermeabilität signifikant reduziert. In dieser Arbeit wurde zum ersten Mal belegt, dass S. aureus FnBPs eine Erhöhung der Endothelpermeabilität bewirken. Während hierfür zu späten Zeitpunkten Apoptose verantwortlich ist, muss nach 4 Stunden ein anderer Mechanismus ursächlich sein. Da es zu einer Abschwächung der ZO-1- und VE-Cadherin-Signalintensität in der Immunfluoreszenz kam, ist anzunehmen, dass Adherens und Tight Junctions durch die Infektion geschädigt werden. Es ist bekannt, dass Src-Kinasen durch die Infektion mit S. aureus aktiviert werden. Außerdem sind sie elementar für die Regulation der Endothelpermeabilität und vermitteln diesen Effekt unter anderem über eine Phosphorylierung von Adherens und Tight Junction-Proteinen. Eine Src-vermittelte Phosphorylierung von Zell-Zell-Verbindungsproteinen wäre daher eine mögliche Erklärung für die beobachteten Veränderungen von ZO-1 und VE-Cadherin. Dieser Mechanismus könnte Wegbereiter für die parazelluläre Passage über die Endothelbarriere sein. Darüber hinaus könnte die erhöhte Endothelpermeabilität den Zugang zur Extrazellulärematrix und zum größten Pool an Fibronektin und Integrinen ermöglichen und so die Invasion und Transzytose begünstigen. Die hier gewonnenen Ergebnisse tragen dazu bei, die komplexe Interaktion zwischen S. aureus und dem Endothel und somit wichtige Schritte in der Pathogenese endovaskulärer Infektionen besser zu verstehen und neue Zielstrukturen für therapeutische Interventionen zu identifizieren. N2 - Staphylococcus aureus (S. aureus) is a major cause of severe endovascular infections which are frequently associated with bacterial dissemination to other organs and life-threatening complications such as infective endocarditis, osteomyelitis or abscess formation. Damage to the endothelial barrier and bacterial extravasation are of vital importance in development of endovascular infections. Intercellular junctions are crucial for the integrity of the endothelial barrier; they are partially regulated by Src Family Protein-tyrosine Kinases. It has been well characterized that S. aureus fibronectin-binding proteins (FnBP) are decisive for adherence to and invasion of endothelial cells. Invasion is mediated by indirect bridging of fibronectin to α5β1-integrins via FnBPs. Invasive characteristics can be found in nearly all clinical isolates. Moreover, the link between expression of FnBPs and S. aureus dissemination into surrounding tissues has been demonstrated repeatedly in animal models. Despite the importance of S. aureus in endovascular diseases, the effect of S. aureus infection on endothelial barrier function and putative mechanisms for translocation have not yet been studied. The aim of this thesis was to evaluate whether infection with different S. aureus and S. carnosus strains leads to impairment of endothelial integrity in EA.hy926 cells. Changes in transendothelial impedance and endothelial permeability upon infection were measured using the xCELLigence- or transwell-system respectively. Cytotoxic effects were quantified by crystal violet staining, immunofluorescence staining of nuclei and mitochondria as well as by detection of hypodiploid nuclei using flow cytometry. Immunofluorescence staining of ZO-1 and VE—Cadherin was performed to investigate morphological alterations in intercellular junctions. The role of Src Family Protein-tyrosine Kinases was analyzed by pharmacological inhibition. In this study it was demonstrated that S. aureus strains expressing FnBPs lead to a decrease in transendothelial impedance and cause a significant increase in endothelial permeability 4 and 24 hours after infection. Whereas cytotoxic effects were observed after 24 hours, cells were completely viable 4 hours after infection. After 4 hours FnBP-dependent conformational changes of VE-cadherin and ZO-1 as well as a loss of signal intensity were detected. Furthermore, the FnBP-mediated increase in endothelial permeability was significantly reduced by using Src Family Protein-tyrosine Kinases-inhibitors. In this study it was shown for the first time that S. aureus FnBPs cause an increase in endothelial permeability. While apoptosis is the underlying mechanism 24 hours after infection, other mechanisms could be identified for the time point 4 hours. Since a loss of signal intensity of ZO-1 and VE-Cadherin was detected, it can be assumed that adherence and tight junctions are impaired upon infection. It has been well characterized that Src Family Protein-tyrosine Kinases are activated upon S. aureus infection and that they are decisive in regulation of endothelial permeability. This effect is mediated by phosphorylation of adherence and tight junction proteins. Hence a Src Family Protein-tyrosine Kinase-mediated phosphorylation of intercellular junction proteins is a conceivable mechanism for the observed change in ZO-1 and VE-cadherin, thus possibly enabling paracellular traverse of the endothelial barrier. On the other hand the increase of endothelial permeability could facilitate access to the extracellular matrix and thus to the biggest pool of fibronectin and integrins, hence promoting bacterial invasion and transcytosis. The obtained results help to understand the complex interaction between S. aureus and endothelial barrier, thus facilitating the understanding of the pathogenesis of endovascular S. aureus infections and possibly identifying new therapy targets. KW - Staphylococcus aureus KW - Staphylococcus aureus KW - Endothelpermeabilität KW - Fibronektin-Bindeprotein Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137303 ER - TY - THES A1 - Schild, Stefan T1 - Bedeutung der Lipopolysaccharidstrukturen bei pathogenen Vibrio cholerae Stämmen für die Ausbildung von Cholera und Abgrenzung zu Umweltisolaten T1 - Importance of LPS structures of virulent Vibrio cholerae strains in correlation with cholera disease and discrimination from environmental strains N2 - Obwohl inzwischen über 200 verschiedene Serogruppen von V. cholerae bekannt sind, wurden Ausbrüche der Cholera hauptsächlich von Stämmen der unbekapselten Serogruppe O1 und der bekapselten Serogruppe O139 verursacht. Die Komponenten des Lipopolysaccharids (LPS) von O1 und O139, sowie die Kapsel von O139 tragen zur Kolonisierung im Gastrointestinaltrakt bei. Um die Funktion des LPS und der Kapsel als Virulenzfaktor näher zu untersuchen, wurden Adhäsionsstudien mit definierten LPS- und/ oder Kapsel-Mutanten beider pathogener Serogruppen durchgeführt. Dazu wurde die Mukus-produzierende humane Darmzelllinie HT-29-Rev MTX verwendet. Im Vergleich zum jeweiligen Wildtyp (Wt) konnte für eine O Antigen-Mutante von O1 eine Reduktion um 85%, für eine O Antigen/ Kapsel-Mutante von O139 eine Reduktion um 70% in der Adhäsionsrate festgestellt werden. Ein Beitrag von ToxR regulierten Genprodukten ist ebenfalls möglich. Weiterhin wurden mit WavJ und WavD zwei Genprodukte der Kernoligosaccharid -Biosynthese charakterisiert, welche bislang nur in dem wa*-Genclustertyp 1 der klinischen Isolate nachgewiesen worden sind. Es konnte gezeigt werden, dass beide Genprodukte an der Biosynthese des Kern OS beteiligt sind, wobei WavJ mit hoher Wahrscheinlichkeit die Heptosyl-IV-Transferase darstellt. Die wavDJ-Doppelmutanten beider Serogruppen wiesen eine erhöhte Sensitivität gegenüber Novobiocin auf. Dagegen konnte eine Attenuation der Mutanten im Mausmodell nur für die Serogruppe O139 demonstriert werden. Ein Schlüsselenzym der LPS-Biosynthese stellt die Oberflächenpolymer:Lipid A-Kern OS-Ligase (WaaL), kurz O Antigen-Ligase genannt, dar. In dieser Arbeit wurden die in der Primärstruktur stark unterschiedlichen Ligasen aus einem pathogenen (P27459) und apathogenen (V194) V. cholerae Isolat strukturell und funktionell analysiert. Es wurde gezeigt, dass die Aktivität beider Ligasen von der Anwesenheit eines N-Acetylglucosamins (GlcNAc) im Kernoligosaccharid abhängig ist. Dieser Zucker wird durch das Genprodukt WavL transferiert, welchem in dieser Arbeit die Aktivität einer N-Acetylglucosaminyltransferase zugeordnet werden konnte. Das Gen wavL wurde in allen zur Verfügung stehenden V. cholerae Isolaten nachgewiesen und stellt wahrscheinlich eine generelle Voraussetzung des Kern OS für eine O Antigen-Anheftung dar. Im Gegensatz dazu, diskriminiert die An- bzw. Abwesenheit einer Galaktose (Gal) im Kern OS die Spezifität der Ligasen von V. cholerae P27459 bzw. V194. Dabei ist die Aktivität der Galaktosyltransferase WavM, essentiell für die Aktivität der Gal-abhängigen Ligase von V194. Die Gal-unabhängige Ligase von P27459 wird hingegen durch die Anwesenheit von Gal im Kern OS inhibiert. Hybridfusionen der beiden Ligasen deuten an, dass die Erkennungsdomäne für Gal in der C-terminalen Hälfte lokalisiert ist. Erstmals wurde die Topologie einer Ligase durch PhoA- und LacZ-Fusionen analysiert. Die Suche nach konservierten Aminosäuren (AS) in verschiedenen Ligasen führte zur Identifizierung der Motive R(X3)L und H(X10)G in zwei periplasmatischen Schleife. Ein Austausch des R oder des H in diesen Motiven führte zum Verlust der Ligase-Aktiviät von WaaL aus V. cholerae und S. enterica. Damit geben diese Motive einen ersten Hinweis auf das aktive Zentrum des Enzyms. Desweiteren wurde nach möglichen O Antigen-Transportern bei V. cholerae gesucht, welche bislang noch nicht identifiziert worden waren. Über die Anpassungen von V. cholerae an aquatische Ökosysteme, insbesondere hinsichtlich der wechselnden Osmolarität, ist nahezu nichts bekannt. Durch ein in dieser Arbeit konstruiertes und etabliertes Transposonsystem konnten 3600 Mutanten erzeugt und auf Wachstumsdefekte unter hypertonischen Bedingungen untersucht werden. Eine dieser osmosensitiven Mutanten wies eine Insertion in dem Locus VCA0565 auf, welcher für eine putative Sensor-Histidinkinase kodiert. Mit dem Regulator, kodiert durch VCA0566, stellt VCA0565 das putative Zwei-Komponentensystem OsmRK dar. Transkriptomanalysen von osmR/ K-Mutanten lieferten keine Erklärung des Wachstumsdefekts unter hypertonischen Bedingungen, zeigten aber eine Vernetzung der durch OsmR/ K regulierten Gene mit dem ToxR-Regulon auf. Analysen der Außenmembran demonstrierten, dass eine Mutation von osmR/ K zu einer Repression von OmpU unter hohen Salzkonzentrationen führt. Vergleichende Experimente mit weiteren Mutanten deuteten an, dass es in osmR/ K- und toxS-Mutanten unter erhöhten Salzkonzentrationen zur Degradation von ToxR kommt. Während die Deregulation von OmpU in osmR/ K-Mutanten nur unter Salzstress zu beobachten war, führte in der toxS-Mutante auch ein Membranstress durch Zugabe von Protamin zu einer Repression von OmpU. Die zu OsmR/ K nah verwandten putativen Zwei-Komponentensysteme EnvZ/ OmpR und VCA0257/ VCA0256 hatten unter keiner der getesteten Bedingungen einen Einfluss auf die Proteine der AM. Weiterhin wurde eine C-terminale Degradation von HutA unter hypertonischen Bedingungen aufgedeckt. N2 - Although, more than 200 serogroups of V. cholerae.were identified, however, only the strains of the non-encapsulated O1 and the encapsulated O139 serogroups were found to be responsible for cholera epidemics. The components of the LPS of O1 and O139 play a crucial role in the colonization of the gastrointestinal tract. To analyze the contribution of the LPS and the capsule in the adhesion to epithelial cells, mucus layer attachment studies using defined O antigen and/ or capsule mutants of both serogroups and the human intestinal cell line HT29-Rev MTX were performed. In case of the O antigen mutant of O1 a 85% and for the O antigen and capsule mutant of O139 a 70% reduction in the adhesion rate was determined compared to wild type. It is likely that ToxR regulated gene products also contribute to the adhesion, since a toxR-mutant of O1 showed a 3-fold reduction in the adhesion rate. In addition the two gene products of the core oligosaccharide biosynthesis, WavJ and WavD, were characterized. So far the corresponding genes could only be found in the wa*-gene cluster type 1 of clinical isolates. It could be demonstrated, that single and double knockout mutants have an effect on core oligosaccharide biosynthesis in both serogroups. Based on bioinformatical data it is likely that WavJ represents the heptosyl-IV-transferase. Double mutants in wavJ and wavD of both serogroups showed an attenuated growth in the presence of novobiocin, whereas only the mutants in O139 demonstrated reduced colonization in the in vivo mouse model. The surface polymer:lipid A-core ligase (WaaL), also called the O antigen ligase, is a key enzyme in the LPS biosynthesis of Gram- bacteria. Part of this work focused on the structural and functional characteristics associated with the recognition of the core oligosaccharide of two distantly related ligases of a virulent (P27459) and an environmental (V194) V. cholerae isolate. It was demonstrated that the activity of both ligases is dependent on the presence of N-acetylglucosamine, which is attached to the core oligosaccharide by the WavL glycosyltransferase. The gene wavL could be found in all V. cholerae isolates so far. In contrast, an additional sugar substitution, i.e. galactose, which is transfered by the WavM galactosyltransferase, discriminates the core oligosaccharide specificity of the ligases of P27459 and V194. The activity of WavM is essential for the activity of the galactose-dependent ligase of V194, whereas it hinders the galactose-independent ligase of P27459 to transfer the O antigen onto the core oligosaccharide. WaaL protein hybrids between galactose dependent and non-dependent ligases indicate that the galactose recognition site is located in the C-terminal half. Using PhoA and LacZ fusions the topology of the ligase of P27459 was determined. Amino acid sequence alignments of WaaL proteins identified the distinct conserved motifs R(X3)L and H(X10)G in two periplasmic loops. By site directed mutagenesis of the histidine and arginine residues within these motifs, an abortism of O antigen transfer reaction for WaaLs of V. cholerae and Salmonella enterica was found. Furthermore the putative O antigen-transport systems of V. cholerae were investigated. In this work a new transposon system was constructed and established, resulting in 3600 mutants, which were screened for growth defects under hypertonic conditions. One of these mutants had an insertion in locus VCA0565, which encodes a putative sensor histidine kinase. In combination with the transcriptional regulator, encoded by VCA0566, they represent the putative two-component system OsmRK. Comparing the transcriptom of osmR/ K-mutants to the wild type revealed no explanation for the osmosensitive phenotype, but showed some interaction between the regulon of OsmR/ K and ToxR. Analysis of the outer membrane demonstrated, that a mutation in osmR/ K results in a repression of OmpU under hypertonic conditions. Comparative experiments, including additional mutants indicated a degradation of ToxR in osmR/ K- and toxS-mutants in presence of high salt concentrations. In contrast to osmR/ K-mutants, in the toxS-mutant the repression of OmpU could be also observed by a different membrane stress caused by protamine. In addition, the analysis of the outer membrane proteins revealed a C-terminal degradation of HutA under hypertonic stress conditions. KW - Vibrio cholerae KW - Lipopolysaccharide KW - Virulenz KW - Osmolarität KW - Vibrio cholerae KW - Lipopolysaccharid KW - O Antigen-Ligase KW - Virulenz KW - Osmolarität KW - Vibrio cholerae KW - lipopolysaccharide KW - O antigen-ligase KW - virulence KW - osmolarity Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-12989 ER - TY - THES A1 - Villwock, Andrea T1 - Bedeutung des Klasse A Scavenger Rezeptors für die Zytokinsekretion von humanen dendritischen Zellen nach Kontakt mit dem humanen Pathogen Neisseria meningitidis T1 - Influence of the class A scavenger receptor for the cytokine secretion by human dendritic cells after contact with the human pathogen Neisseria meningitidis N2 - Meningokokken gehören zu den wichtigsten Erregern bakterieller Sepsis und Meningitis. Der Schweregrad des Krankheitsverlaufs bei Meningokokkenerkrankungen korreliert mit der Konzentration an proinflammatorischen Zytokinen im Serum. Dendritische Zellen (DZ) bilden die erste Abwehr am humanen Epithel des Nasopharynx, welches die Eingangspforte von Neisseria meningitidis darstellt und sind eine wichtige Quelle proinflammatorischer Zytokine. In dieser Arbeit konnte gezeigt werden, dass bekapselte Meningokokken-Stämme bei DZ signifikant weniger proinflammatorische Zytokine als isogene Kapsel-defiziente Stämme oder obligat unbekapselte Stämme induzieren. Dieser Effekt ist unabhängig von der chemischen Zusammensetzung der Kapsel, da aufgereinigtes Kapselpolysaccharid der Serogruppe B nicht den reduzierenden Effekt der Zytokininduktion beeinflusste. Darüber hinaus spielt die Kapsel-O-Acetylierung bei Serogruppe C, W-135 und Y nur eine untergeordnete Rolle bei der Erkennung von Meningokokken durch DZ. Microarray Versuche zum Transkriptionsprofil von DZ, die mit dem konstitutiv unbekapselten Trägerisolat alpha 14, dem bekapselten MC58 oder dem isogenen unbekapselten Stamm MC58siaD durchgeführt wurden, zeigten nach 4 h ein identisches Profil von proinflammatorischen Zytokinen. Nur der phagozytierte unbekapselten Stamm MC58siaD zeigte eine differentielle Regulation von weiteren Zytokinen. Jedoch glich sich das Profil nach 18 h Infektion durch alle drei Stämme an. Der Scavenger Rezeptor der Klasse A (SR-A) wurde als Hauptrezeptor identifiziert, der die Erkennung und Phagozytose von Meningokokken durch DZ initialisiert. Eine Assoziation phagozytierter Meningokokken mit SR-A konnte mittels Elektronenmikroskopie bestätigt werden. Nach Infektion von THP-1 Makrophagen mit bekapselten Serogruppe B und C Stämmen, den isogenen Kapsel-defizienten Stämmen und dem obligat unbekapselten Stamm alpha 14 wurde auf Transkriptionsebene keine differentielle Regulation der SR-A nachgewiesen. Lediglich eine minimale Hochregulation des SR-A auf der zellulären Oberfläche konnte nach einer Stunde Infektion verzeichnet werden. Nach Infektion von DZ oder THP-1 Makrophagen mit MC58siaD kommt es zur Dephosphorylierung des SR-A. Unter Verwendung von globalen Phagozytose-Inhibitoren konnte gezeigt werden, dass für die maximale Induktion der proinflammatorischen Zytokine TNF-alpha, IL-6 und IL-1 Phagozytose von N. meningitidis benötigen wird, dies ist jedoch für die IL 8 Produktion nicht notwendig. Außerdem konnte gezeigt werden, dass mit dem spezifischen SR-A Inhibitor poly G eine Reduktion von TNF-alpha, IL-6, IL-1 und IL-8 zu verzeichnen war. Folglich ist die Phagozytose über SR-A nötig, um TNF-alpha, IL-6 und IL-1 zu induzieren, jedoch nur die Erkennung aber nicht die Phagozytose via SR-A die IL-8 Produktion initiiert. Die Aufnahme von Neisseria meningitidis über den SR-A durch DZ ist damit nicht nur für die Phagozytose und Abtötung verantwortlich sondern auch für die Zytokininduktion wichtig ist. Es gibt jedoch auch Meningokokken Stämme, die nicht vom SR-A erkannt werden. Mit alpha 14 konnte erstmals ein Meningokokken-Stamm identifiziert werden, der nicht an SR-A bindet. Die Induktion von Zytokinfreisetzung durch alpha 14 erfolgt dementsprechend unabhängig von SR-A und nach Kontakt von alpha 14 mit humanen DZ ist keine Veränderung der Phosphorylierungsstatus dieses Rezeptors zu beobachten. Die erhobenen Daten legen eine zentrale Rolle von SR-A in der Induktion von Immunität gegen N. meningitidis nahe. N2 - Meningococci belong to the most important pathogens which cause bacterial sepsis and meningitis. The severity and outcome of meningococcal disease correlates with the concentration of proinflammatory cytokines in the serum. Dendritic cells (DC) build a first line of defence within the nasopharyngeal epithelium, which is the port-of-entry for Neisseria meningitidis and are an important source of proinflammatory cytokines. Infection of DC with encapsulated meningococcal strains induces significantly lower levels of proinflammatory cytokines than isogenic capsule-deficient mutants or constitutively unencapsulated strains. It could be shown that this effect does not depend on the chemical composition of the meningococcal capsule, because purified capsular polysaccharide of serogroup B is unable to modulate cytokine secretion. O-acetylation of serogroup C, W-135 and Y capsules plays a minor role in the recognition of meningococci by DC. Microarray studies on the expression of cytokine genes by DC infected with constitutively unencapsulated carriage isolate alpha 14, encapsulated serogroup B strain MC58 or the isogenic unencapsulated strain MC58siaD showed an identical pattern for proinflammatory cytokines after 4 h of infection. Only the unencapsulated strain MC58siaD which is easily phagocytosed induced additional cytokines. However, the cytokine profile after 18 h of infection was equal for all three strains. Scavenger receptor A (SR-A) was identified as the main receptor mediating recognition and phagocytosis of meningococci by DC. Association of phagocytosed meningococci with SR-A was visualized by electron microscopy. Infection of THP-1 macrophages with encapsulated serogroup B und C strains, their isogentic capsule-deficient muntants or the obligatory unencapsulated strain alpha 14 did not induce differential regulation of SR-A on the transcriptional level and only minor up-regulation of SR-A on cellular surface after one hour of infection. After infection of DC or THP-1 macrophages with MC58siaD dephosphorylation of SR-A can be detected. Using global phagocytosis inhibitors, it could be determined that the induction of the proinflammatory cytokines TNF-alpha, IL-6 and IL-1 require phagocytosis of N. meningitidis, whereas induction of IL-8 does not. In addition, the specific SR-A-inhibitor poly G also leads to a reduction of TNF-alpha, IL-6, IL-1 and IL-8 secretion. Taken together these data indicate that phagocytosis via SR-A is necessary for TNF-alpha, IL-6 and IL-1 secretion, whereas recognition but not phagocytosis via SR-A enhances IL-8 secretion. Therefore, the uptake of Neisseria meningitidis via SR-A is not only important for phagocytosis and killing but also involved in cytokine induction. However, not all meningococcal strains are recognized via SRA. The cytokine induction by DZ infected with alpha 14 is completely independent of SR-A and after contact of human DC with alpha 14 no changes in SR-A phosphorylation can be detected. These data suggest that SR-A plays a central role in the induction of immunity against N. meningitidis. KW - Neisseria meningitidis KW - Scavenger-Rezeptor KW - Cytokine KW - Kapsel O-Acetylieung KW - capsule O-Acetylation Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-28555 ER - TY - JOUR A1 - Schlesinger, Tobias A1 - Weißbrich, Benedikt A1 - Wedekink, Florian A1 - Notz, Quirin A1 - Herrmann, Johannes A1 - Krone, Manuel A1 - Sitter, Magdalena A1 - Schmid, Benedikt A1 - Kredel, Markus A1 - Stumpner, Jan A1 - Dölken, Lars A1 - Wischhusen, Jörg A1 - Kranke, Peter A1 - Meybohm, Patrick A1 - Lotz, Christpher T1 - Biodistribution and serologic response in SARS-CoV-2 induced ARDS: A cohort study JF - PLoS One N2 - Background The viral load and tissue distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain important questions. The current study investigated SARS-CoV-2 viral load, biodistribution and anti-SARS-CoV-2 antibody formation in patients suffering from severe corona virus disease 2019 (COVID-19) induced acute respiratory distress syndrome (ARDS). Methods This is a retrospective single-center study in 23 patients with COVID-19-induced ARDS. Data were collected within routine intensive care. SARS-CoV-2 viral load was assessed via reverse transcription quantitative polymerase chain reaction (RT-qPCR). Overall, 478 virology samples were taken. Anti-SARS-CoV-2-Spike-receptor binding domain (RBD) antibody detection of blood samples was performed with an enzyme-linked immunosorbent assay. Results Most patients (91%) suffered from severe ARDS during ICU treatment with a 30-day mortality of 30%. None of the patients received antiviral treatment. Tracheal aspirates tested positive for SARS-CoV-2 in 100% of the cases, oropharyngeal swabs only in 77%. Blood samples were positive in 26% of the patients. No difference of viral load was found in tracheal or blood samples with regard to 30-day survival or disease severity. SARS-CoV-2 was never found in dialysate. Serologic testing revealed significantly lower concentrations of SARS-CoV-2 neutralizing IgM and IgA antibodies in survivors compared to non-survivors (p = 0.009). Conclusions COVID-19 induced ARDS is accompanied by a high viral load of SARS-CoV-2 in tracheal aspirates, which remained detectable in the majority throughout intensive care treatment. Remarkably, SARS-CoV-2 RNA was never detected in dialysate even in patients with RNAemia. Viral load or the buildup of neutralizing antibodies was not associated with 30-day survival or disease severity. KW - viral load Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231348 VL - 15, 2020 IS - 11 ER - TY - JOUR A1 - Straub, Anton A1 - Stapf, Maximilian A1 - Fischer, Markus A1 - Vollmer, Andreas A1 - Linz, Christian A1 - Lâm, Thiên-Trí A1 - Kübler, Alexander A1 - Brands, Roman C. A1 - Scherf-Clavel, Oliver A1 - Hartmann, Stefan T1 - Bone concentration of ampicillin/sulbactam: a pilot study in patients with osteonecrosis of the jaw JF - International Journal of Environmental Research and Public Health N2 - Osteonecrosis of the jaw (ONJ) occurs typically after irradiation of the head and neck area or after the intake of antiresorptive agents. Both interventions can lead to compromised bone perfusion and can ultimately result in infection and necrosis. Treatment usually consists of surgical necrosectomy and prolonged antibiotic therapy, usually through beta-lactams such as ampicillin/sulbactam. The poor blood supply in particular raises the question as to whether this form of antibiosis can achieve sufficient concentrations in the bone. Therefore, we investigated the antibiotic concentration in plasma and bone samples in a prospective study. Bone samples were collected from the necrosis core and in the vital surrounding bone. The measured concentrations in plasma for ampicillin and sulbactam were 126.3 ± 77.6 and 60.2 ± 35.0 µg/mL, respectively. In vital bone and necrotic bone samples, the ampicillin/sulbactam concentrations were 6.3 ± 7.8/1.8 ± 2.0 µg/g and 4.9 ± 7.0/1.7 ± 1.7 µg/g, respectively. These concentrations are substantially lower than described in the literature. However, the concentration seems sufficient to kill most bacteria, such as Streptococci and Staphylococci, which are mostly present in the biofilm of ONJ. We, therefore, conclude that intravenous administration of ampicillin/sulbactam remains a valuable treatment in the therapy of ONJ. Nevertheless, increasing resistance of Escherichia coli towards beta-lactam antibiotics have been reported and should be considered. KW - osteonecrosis of the jaw KW - ARONJ KW - MRONJ KW - ONJ KW - osteoradionecrosis KW - antibiotic bone concentration KW - jaw bone KW - beta-lactam KW - ampicillin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297413 SN - 1660-4601 VL - 19 IS - 22 ER - TY - JOUR A1 - Maiden, Martin C. J. A1 - Frosch, Matthias T1 - Can we, should we, eradicate the meningococcus? JF - Vaccine N2 - The eradication of infectious agents is an attractive means of disease control that, to date, has been achieved for only one human pathogen, the smallpox virus. The introduction of vaccines against Neisseria meningitidis into immunisation schedules, and particularly the conjugate polysaccharide vaccines which can interrupt transmission, raises the question of whether disease caused by this obligate human bacterium can be controlled, eliminated, or even eradicated. The limited number of meningococcal serogroups, lack of an animal reservoir, and importance of meningococcal disease are considerations in favour of eradication; however, the commensal nature of most infections, the high diversity of meningococcal populations, and the lack of comprehensive vaccines are all factors that suggest that this is not feasible. Indeed, any such attempt might be harmful by perturbing the human microbiome and its interaction with the immune system. On balance, the control and possible elimination of disease caused by particular disease-associated meningococcal genotypes is a more achievable and worthwhile goal. KW - population biology KW - epidemiology KW - vaccines KW - neisseria meningitidis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125646 VL - 30 IS - Suppl. 2 ER - TY - JOUR A1 - Apsemidou, Athanasia A1 - Füller, Miriam Antonie A1 - Idelevich, Evgeny A. A1 - Kurzai, Oliver A1 - Tragiannidis, Athanasios A1 - Groll, Andreas H. T1 - Candida lusitaniae breakthrough fungemia in an immuno-compromised adolescent: case report and review of the literature JF - Journal of Fungi N2 - Candida lusitaniae is a rare cause of candidemia that is known for its unique capability to rapidly acquire resistance to amphotericin B. We report the case of an adolescent with grade IV graft-vs.-host disease after hematopoietic cell transplantation who developed catheter-associated C. lusitaniae candidemia while on therapeutic doses of liposomal amphotericin B. We review the epidemiology of C. lusitaniae bloodstream infections in adult and pediatric patients, the development of resistance, and its role in breakthrough candidemia. Appropriate species identification, in vitro susceptibility testing, and source control are pivotal to optimal management of C. lusitaniae candidemia. Initial antifungal therapy may consist of an echinocandin and be guided by in vitro susceptibility and clinical response. KW - Candida lusitaniae KW - candidemia KW - resistance KW - breakthrough KW - infection KW - transplantation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-220125 SN - 2309-608X VL - 6 IS - 4 ER - TY - JOUR A1 - Page, Lukas A1 - Wallstabe, Julia A1 - Lother, Jasmin A1 - Bauser, Maximilian A1 - Kniemeyer, Olaf A1 - Strobel, Lea A1 - Voltersen, Vera A1 - Teutschbein, Janka A1 - Hortschansky, Peter A1 - Morton, Charles Oliver A1 - Brakhage, Axel A. A1 - Topp, Max A1 - Einsele, Hermann A1 - Wurster, Sebastian A1 - Loeffler, Juergen T1 - CcpA- and Shm2-Pulsed Myeloid Dendritic Cells Induce T-Cell Activation and Enhance the Neutrophilic Oxidative Burst Response to Aspergillus fumigatus JF - Frontiers in Immunology N2 - Aspergillus fumigatus causes life-threatening opportunistic infections in immunocompromised patients. As therapeutic outcomes of invasive aspergillosis (IA) are often unsatisfactory, the development of targeted immunotherapy remains an important goal. Linking the innate and adaptive immune system, dendritic cells are pivotal in anti-Aspergillus defense and have generated interest as a potential immunotherapeutic approach in IA. While monocyte-derived dendritic cells (moDCs) require ex vivo differentiation, antigen-pulsed primary myeloid dendritic cells (mDCs) may present a more immediate platform for immunotherapy. To that end, we compared the response patterns and cellular interactions of human primary mDCs and moDCs pulsed with an A. fumigatus lysate and two A. fumigatus proteins (CcpA and Shm2) in a serum-free, GMP-compliant medium. CcpA and Shm2 triggered significant upregulation of maturation markers in mDCs and, to a lesser extent, moDCs. Furthermore, both A. fumigatus proteins elicited the release of an array of key pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, IL-8, and CCL3 from both DC populations. Compared to moDCs, CcpA- and Shm2-pulsed mDCs exhibited greater expression of MHC class II antigens and stimulated stronger proliferation and IFN-γ secretion from autologous CD4\(^+\) and CD8\(^+\) T-cells. Moreover, supernatants of CcpA- and Shm2-pulsed mDCs significantly enhanced the oxidative burst in allogeneic neutrophils co-cultured with A. fumigatus germ tubes. Taken together, our in vitro data suggest that ex vivo CcpA- and Shm2-pulsed primary mDCs have the potential to be developed into an immunotherapeutic approach to tackle IA. KW - antigens KW - dendritic cells KW - cytokines KW - host defense KW - immunotherapy KW - Aspergillus Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239493 SN - 1664-3224 VL - 12 ER - TY - JOUR A1 - Slanina, Heiko A1 - Hebling, Sabrina A1 - Hauck, Christoph R. A1 - Schubert-Unkmeir, Alexandra T1 - Cell Invasion by Neisseria meningitidis Requires a Functional Interplay between the Focal Adhesion Kinase, Src and Cortactin N2 - Entry of Neisseria meningitidis (the meningococcus) into human brain microvascular endothelial cells (HBMEC) is mediated by fibronectin or vitronectin bound to the surface protein Opc forming a bridge to the respective integrins. This interaction leads to cytoskeletal rearrangement and uptake of meningococci. In this study, we determined that the focal adhesion kinase (FAK), which directly associates with integrins, is involved in integrin-mediated internalization of N. meningitidis in HBMEC. Inhibition of FAK activity by the specific FAK inhibitor PF 573882 reduced Opc-mediated invasion of HBMEC more than 90%. Moreover, overexpression of FAK mutants that were either impaired in the kinase activity or were not capable of autophosphorylation or overexpression of the dominant-negative version of FAK (FRNK) blocked integrin-mediated internalization of N. meningitidis. Importantly, FAK-deficient fibroblasts were significantly less invaded by N. meningitidis. Furthermore, N. meningitidis induced tyrosine phosphorylation of several host proteins including the FAK/Src complex substrate cortactin. Inhibition of cortactin expression by siRNA silencing and mutation of critical amino acid residues within cortactin, that encompass Arp2/3 association and dynamin binding, significantly reduced meningococcal invasion into eukaryotic cells suggesting that both domains are critical for efficient uptake of N. meningitidis into eukaryotic cells. Together, these results indicate that N. meningitidis exploits the integrin signal pathway for its entry and that FAK mediates the transfer of signals from activated integrins to the cytoskeleton. A cooperative interplay between FAK, Src and cortactin then enables endocytosis of N. meningitidis into host cells. KW - Medizin Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75354 ER - TY - JOUR A1 - Nieuwenhuizen, Natalie E. A1 - Evans, Joanna C. T1 - Cellular and molecular mechanisms in mycobacterial infection JF - International Journal of Molecular Sciences N2 - No abstract available KW - mycobacterial infection Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284370 SN - 1422-0067 VL - 23 IS - 13 ER - TY - JOUR A1 - Lichtenegger, Sabine A1 - Bina, Isabelle A1 - Roier, Sandro A1 - Bauernfeind, Stilla A1 - Keidel, Kristina A1 - Schild, Stefan A1 - Anthony, Mark A1 - Reidl, Joachim T1 - Characterization of lactate utilization and its implication on the physiology of Haemophilus influenzae JF - International Journal of Medical Microbiology N2 - Haemophilus influenzae is a Gram-negative bacillus and a frequent commensal of the human nasopharynx. Earlier work demonstrated that in H. influenzae type b, l-lactate metabolism is associated with serum resistance and in vivo survival of the organism. To further gain insight into lactate utilization of the non-typeable (NTHi) isolate 2019 and laboratory prototype strain Rd KW20, deletion mutants of the l-lactate dehydrogenase (lctD) and permease (lctP) were generated and characterized. It is shown, that the apparent KM of l-lactate uptake is 20.1μM as determined for strain Rd KW20. Comparison of the COPD isolate NTHi 2019-R with the corresponding lctP knockout strain for survival in human serum revealed no lactate dependent serum resistance. In contrast, we observed a 4-fold attenuation of the mutant strain in a murine model of nasopharyngeal colonization. Characterization of lctP transcriptional control shows that the lactate utilization system in H. influenzae is not an inductor inducible system. Rather negative feedback regulation was observed in the presence of l-lactate and this is dependent on the ArcAB regulatory system. Additionally, for 2019 it was found that lactate may have signaling function leading to increased cell growth in late log phase under conditions where no l-lactate is metabolized. This effect seems to be ArcA independent and was not observed in strain Rd KW20. We conclude that l-lactate is an important carbon-source and may act as host specific signal substrate which fine tunes the globally acting ArcAB regulon and may additionally affect a yet unknown signaling system and thus may contribute to enhanced in vivo survival. KW - colonization KW - haemophilus influenzae KW - I-lactate KW - utilization KW - IctP Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121335 VL - 304 IS - 3-4 ER - TY - THES A1 - Pasquet, Vivian T1 - Characterization of thioredoxin and glutathione reductase activities of Mesocestoides vogae, a flatworm parasite useful as a laboratory model for the screening of drugs. T1 - Charakterisierung von Thioredoxin- und Glutathionreduktase Aktivitäten von Mesocestoides vogae, einem parasitären Plattwurm der als Labormodell für die Testung von Arzneistoffen verwendet werden kann N2 - Flatworm parasites (platyhelminths) cause serious infection diseases in humans, such as schistosomiasis and hydatid disease, mainly prevalent in developing countries. However, the current repertoire of drug armamentarium used to combat flatworm infections is limited. For instance, praziquantel is the only drug available for mass treatment of Schistosoma infections. In contrast to their hosts, flatworm parasites possess a distinct redox arrangement of redox pathways in which the selenoenzyme thioredoxin glutathione reductase (TGR) controls the overall redox homeostasis. Interference with this enzyme leads to parasite death. Hence, this key redox enzyme seems to be a new promising drug target against flatworm infections. Because most flatworms are difficult to cultivate in the laboratory (e.g. Echinococcus granulosus experimental infection in mice takes about 10 month to develop into cysts), this work was focused on Mesocestoides vogae (syn. corti), a non-human flatworm parasite which is an interesting laboratory model to study other flatworm infections: it is very rare in humans, can be easily manipulated both in vivo and in vitro and grows extremely fast in mice. With the aim to assess TGR inhibitors as possible drugs to treat flatworm infections, the thioredoxin and glutathione pathways of M.vogae were studied. Here, the objectives were to study whether the biochemical pathways that maintain the redox homeostasis in M. vogae conform to the general biochemical scenario proposed for other platyhelminth parasites. Here, it was proven that M. vogae extracts possess both thioredoxin and glutathione reductase activities. The thioredoxin and glutathione reductase activities were partially purified from total extracts by a combination of ammonium sulfate precipitation, anion exchange and hydroxyapatite chromatography. Both activities co-purified in all steps which strongly indicates the existence of TGR rather than a single TR and GR. Furthermore partially purified activities could be inhibited by the organogold compound auranofin, a known TGR inhibitor. Moreover, the glutathione reductase activity displays hysteresis (a peculiar kinetic behavior) at high concentrations of oxidised glutathione, a feature typical of flatworm TGRs, but not of conventional GR. Although M. vogae activities could not be purified to homogeneity, the overall results strongly indicate that this flatworm possesses TGR and lacks conventional GR and TR. Furthermore the thiadiazole WPQ75 and the N-oxide VL16E (a furoxan derivate) were identified as inhibitors of TGR activity of M.vogae at a 10 µM concentration. These inhibitors were able to kill M.vogae larval worms in vitro as well as in experimental infection in mice. Due to the existence of TGR activity in M.vogae, the possibility to inhibit this activity with recently discovered inhibitors of flatworm TGR and the successes achieved by testing these inhibitors both in vitro and in vivo, it is strongly evident that M. vogae would be an excellent model to assess TGR inhibitors in flatworm infections. N2 - Charakterisierung von Thioredoxin- und Glutathionreduktase Aktivitäten von Mesocestoides vogae, einem parasitären Plattwurm der als Labormodell für die Testung von Arzneistoffen verwendet werden kann KW - Thioredoxin KW - Mesocestoides vogae KW - Glutathione Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-106759 ER - TY - THES A1 - Benke, Dominik T1 - Charakterisierung der T2-Ribonuklease des Fuchsbandwurms \(Echinococcus\) \(multilocularis\) T1 - Charcterisation of the T2-Ribonuclease of \(Echinococcus\) \(multilocularis\) N2 - Die alveoläre Echinokokkose ist eine lebensbedrohliche Erkrankung, die durch tumorartig in der Leber wachsende Larven (Metazestoden) des Fuchsbandwurms ausgelöst wird. Während Th1-dominierte Immunantworten zur Expulsion des Parasiten führen können, sind Th2-Antworten mit chronischer Infektion assoziiert. Über seine exkretorisch-sekretorischen Produkte (ESPs) nimmt Echinococcus multilocularis Einfluss auf die Polarisierung der Immunantwort. Allerdings ist bislang nur wenig über die zugrundeliegenden Mechanismen und aktiven Komponenten der ESPs bekannt. Die Immunmodulation durch Eier des Pärchenegels Schistosoma mansoni, der wie E. multilocularis zu den Plattwürmern gehört, ist dagegen schon besser charakterisiert. Hier hat omega-1, eine Ribonuklease der T2-Familie, Aufmerksamkeit als starker Induktor von Th2-Antworten und als Hepatotoxin erregt. Die Fragestellung dieser Arbeit war nun, ob die T2-RNase des Fuchsbandwurms (EmRNASET2) hinsichtlich ihrer Wirkungen auf Zellen des Immunsystems und der Leber Ähnlichkeiten mit omega-1 besitzt. Es konnte gezeigt werden, dass EmRNASET2 von allen Larvenstadien und auch vom adulten Wurm exprimiert wird. Der Einsatz polyklonaler Antikörper gegen rekombinant in Escherichia coli exprimierte recEmRNASET2 ermöglichte den Nachweis des Proteins in den ESPs von Primärzellen, die das frühe Stadium sich entwickelnder Metazestoden darstellen, und, wenngleich geringer ausgeprägt, in ESPs reifer Metazestoden. Zur Untersuchung einer möglichen immunmodulatorischen Wirkung wurden dendritische Zellen (DCs) aus murinem Knochenmark generiert und mit Überständen recEmRNASET2-produzierender HEK-Zellen exponiert. Diese zeigten im Vergleich zu Überständen von mit leerem Transfektionsvektor behandelten HEK-Zellen keine signifikante Inhibition der LPS-induzierten Reifung und Interleukin-12-Produktion von DCs, wie sie für omega-1 beschrieben ist. Auch ein Pilotexperiment mit der Leberzelllinie Hep3B lieferte keinen Anhalt für eine hepatotoxische Wirkung von EmRNASET2. Somit sprechen die Ergebnisse dieser Arbeit gegen eine funktionelle Verwandtschaft von EmRNASET2 und omega-1. Unterstützt wird diese Beobachtung durch eine orientierende phylogenetische Untersuchung, in der sich EmRNASET2 näher verwandt zu einer zweiten T2-RNase von S. mansoni zeigte. Omega-1 könnte also das Resultat einer Genduplikation mit anschließender Akquirierung immunmodulatorischer Funktionen sein. N2 - Alveolar Echinococcosis is a life-threatening disease caused by larvae (metacestodes) of the fox tapeworm, growing infiltratively in the liver. While Th1-dominated immune responses can lead to parasite expulsion, Th2-responses are associated with chronic infection. Through its excretory-secretory products (ESPs), Echinoccoccus multilocularis can influence polarisation of the immune response. However, little is known about the underlying mechanisms and active components of the ESPs. In contrast, immunomodulation by eggs of the blood fluke Schistosoma mansoni, a flat worm like E. multilocularis, has already been characterised more intensively and omega-1, a ribonuclease of the T2-family, has been identified as a major inductor of Th2-responses and as hepatotoxin. The aim of this study was to determine if the T2-RNase of E. multilocularis (EmRNASET2) has effects on cells of the immune system and the liver that are similar to those of omega-1. It could be shown that EmRNASET2 is expressed by all larval stages and by the adult worm. The use of polyclonal antibodies raised against the recombinantly expressed recEmRNASET2 allowed the detection of the protein in ESPs of primary cells, representing an early stage of developing metacestodes, and, however at a lower level, in ESPs of mature metacestodes. In order to address a potential immunomodulatory role, dendritic cells (DCs) were generated from murine bone marrow and exposed to supernatants of recEmRNASET2-producing HEK-cells. Compared to supernatants of HEK-cells transfected with the empty vector, conditioned medium did not show a significant inhibition of the LPS-induced maturation and interleukin-12 production of DCs, as described for omega-1. Moreover, a pilot experiment using the liver cell line Hep3B did not show evidence for a hepatotoxic effect of EmRNASET2. The results of this work therefore do not speak for a functional similarity of EmRNASET2 and omega-1. These observations are underlined by phylogenetic analyses, showing that EmRNASET2 clusters with a second T2-RNase from S. mansoni. Omega-1 could therefore be the result of a gene duplication event, with subsequent acquisition of its immunomodulatory functions. KW - Parasitologie KW - Immunologie KW - Alveoläre Echinokokkose KW - Ribonucleasen KW - Dendritische Zelle KW - Immunoparasitologie Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181064 ER - TY - THES A1 - Bösl, Maria T1 - Charakterisierung des Zwei-Partner-Sekretionssystems von Meningokokken T1 - Characterisation of the two-partner-secretion-system in meningococci N2 - Ein Proteintransportsystem genannt Zwei-Partner-Sekretionssystem ist bei gram-negativen Bakterien weit verbreitet. In B. pertussis ist es bereits ausführlich untersucht. Diese Arbeit widmet sich dem Zwei-Partner-Sekretionssystem in Meningokokken. N2 - Characterisation of a protein transoport system in meningococci. This system, called two-partner-secretion-system is allready well examined in B. pertussis. KW - Neisseria meningitidis KW - TPS-System KW - Proteintransport KW - two-partner-secretion-system Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-28810 ER - TY - THES A1 - Bernthaler, Peter T1 - Charakterisierung und Funktionsanalyse von EmRSK4, einem TGF-beta Typ II-Rezeptor aus Echinococcus multilocularis T1 - Characterization of EMRSK4 a TGF-beta Typ II-Rezeptor from Echinococcus multilocularis N2 - Die Alveoläre Echinokokkose ist eine bedeutende, gefährliche Parasitose des Menschen. Über die molekularen Grundlagen und Mechanismen der Wirt-Parasit- Interaktion ist bislang nur wenig bekannt. In den letzten Jahren konnten Hinweise erlangt werden, dass Wirt und Parasit über evolutionsgeschichtlich konservierte Signalsysteme kommunizieren. Eines dieser Systeme ist das TGF-b/BMP-Signaltransduktionssystem. TGF-β-Signaltransduktionskomponenten steuern grundlegende Prozesse der Entwicklung und Differenzierung in allen Tieren. Über dieses Signalsystem wird ein weites Spektrum von zellulären Prozessen wie Proliferation, Apoptose und Differenzierung reguliert. Dieses System besteht aus strukturell verwandten Zytokinen der TGF-β (transforming growth factor β) bzw. BMP (bone morphogenetic protein)-Familie, membranständigen Rezeptoren der TGF-β-Rezeptorfamilie (Typ I und Typ II) sowie intrazellulären Signaltransduktoren der Smad-Familie. Bislang konnten verschiedene Echinokokken Smad-Faktoren (EmSmadA, EmSmadB, EmSmadC und EmSmadD) sowie drei Echinokokken Rezeptoren der Typ I Familie (EmRSK1, EmRSK2, EmRSK3) in E. multilocularis identifiziert werden. Ein Mitglied der TGF-β Typ II-Rezeptorfamilie war bislang noch nicht beschrieben. In dieser Arbeit wird ein solches Molekül vorgestellt, EmRSK4 (=TGF-b Typ IISerin/ Threonin Kinase Rezeptor aus Echinococcus multilocularis). Genexpressionsanalysen und immunhistochemische Untersuchungen zeigen an, dass EmRSK4 in der Germinalschicht des E. multilocularis Metacestoden zusammen mit EmRSK1 (=BMP Typ I-Serin/Threonin Kinase Rezeptor) exprimiert wird. Studien an heterolog exprimierten Rezeptoren zeigten, dass EmRSK4 funktionell aktiv ist und mit humanen Typ I-Rezeptoren einen Komplex bilden kann. Diese Studien zeigen auch, dass EmRSK4 mit EmRSK1 einen aktiven heterologen Typ I-/Typ II-Rezeptorkomplex in HEK293-T Zellen bildet, der durch Wirts-BMP2 stimuliert wird und EmSmadB aktiviert. In Untersuchungen mit EmRSK2 (= TGF-β Typ ISerin/ Threonin Kinase Rezeptor) konnte gezeigt werden, dass bei Anwesenheit beider Rezeptoren, EmRSK2 und EmRSK4, eine Phosphorylierung von EmSmadC nachweisbar ist, während eine Phosphorylierung von EmSmadA auch ohne die Anwesenheit von EmRSK4 stattfindet. Desweiteren konnte gezeigt werden, dass der Inhibitor SB-431452 die Kinaseaktivität von EmRSK2 hemmt. Nach Zugabe von exogenem BMP2 zu Metazestodenvesikel konnten Hinweise erhalten werden, dass ein bislang noch nicht charakterisiertes, zusätzliches EmSmad aktiviert wird. Zusammengenommen lässt die Co-Expression von EmRSK1 mit EmRSK4 in der Germinalschicht, die Bildung eines BMP-responsiven Komplexes aus beiden Rezeptoren und die Phosphorylierung mindestens eines zellulären Faktors nach exogener Zugabe von Wirts-BMP2 zu Metacestodenvesikeln darauf schließen, dass beide Rezeptoren während einer Infektion an der Sensierung von BMP Signalen des Wirts beteiligt sein könnten N2 - Alveolar echinococcosis is an important and dangerous parasitosis in humans which is caused by the larval stage of the fox-tapeworm E. multilocularis. Up to now, little is known about the molecular mechanisms of the interaction between the human host and the parasite. During recent years, evidence could be obtained that the host and the parasite communicate through evolutionary conserved signal systems. One of these is the TGF- β/BMP signal transduction system. TGF-β signal transduction components regulate basic processes of development and differentiation in all animals such as proliferation, apoptosis and differentiation. The system consists of structurally related cytokines of the TGF-β (transforming growth factor β)/BMP (bone morphogenetic protein) family, transmembrane receptors of the TGF-β receptor family called the type I and type II receptor as well as intracellular signal transducers of the Smad family. So far different Echinococcus Smad factors (EmSmadA, EmSmadB, EmSmadC and EmSmadD) as well as three Echinococcus receptors of the type I family (EmRSK1, EmRSK2 and EmRSK3) have been identified. No member of the TGF-β type II receptor family has as yet been reported for E. multilocularis. In this study such a receptor, EmRSK4 (=TGF-β type II serine/threonine kinase receptor from Echinococcus multilocularis), has been identified and characterized. Gene expression studies and immunohistochemistry show that EmRSK4 and EmRSK1 (=TGF-β type I serine/threonine kinase receptor) are co-expressed together in the germinal layer of the parasitic metacestode. Studies on heterologously expressed receptors show that EmRSK4 is able to form a functionally active complex with EmRSK1 which is stimulated by host BMP2 and activates EmSmadB. Studies with EmRSK2 (=TGF-β type I serine/threonine kinase receptor) showed that a phosphorylation of EmSmadC is only detectable in the presence of both receptors, EmRSK2 and EmRSK4, while EmRSK2 does not require EmRSK4 for activating EmSmadA. Furthermore it could be shown that the inhibitor SB-431452 inhibits the kinase activity of EmRSK2. After addition of exogenous BMP2 to metacestode vesicles elevated phosphorylation of an as yet uncharacterized Smad-factor was detected, indicating that intact parasite vesicles are able to respond to exogenous host cytokines. Taken together the Co-expression of EmRSK1 and EmRSK4 in the germinal layer, the formation of a BMP responsive complex and the phosphorylation of at least onecellular factor after exogenous addition of host BMP2 to metacestode vesicles suggest that both receptors play a role in sensing of BMP signals during an infection. KW - Fuchsbandwurm KW - Ecinococcus multilocularis KW - TGF-beta KW - Typ II-Rezeptor KW - Signalsystem KW - Ecinococcus multilocularis KW - TGF-beta KW - Typ II-receptor KW - signaltransduction Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-37244 ER - TY - THES A1 - Kaasch, Achim J. T1 - Charakterisierung und Lokalisation der Toxoplasma gondii Katalase: Peroxisomen in Apicomplexa? T1 - Characterisation and Localization of Toxoplasma gondii Catalase: Peroxisomes in Apicomplexa? N2 - Toxoplasma gondii ist ein obligat intrazellulärer, einzelliger Parasit aus dem Phylum der Apicomplexa. Infektionen des Menschen mit T. gondii verlaufen meist subklinisch. Nach einer Infektion persistiert der Erreger für viele Jahre in Hirn- und Muskelgewebe. Durch Reaktivierung des Erregers, z. B. durch eine Immunschwächekrankheit oder unter Immunsuppression, kann eine Enzephalitis mit septischer Streuung entstehen. Eine diaplazentare Infektion führt zur Fetopathia toxoplasmotica mit Früh- und Totgeburten oder zu der typischen enzephalitischen Trias aus Chorioretinitis, Hydrozephalus und zerebralen Verkalkungen. Ein Mechanismus, der es T. gondii ermöglicht im Wirtsorganismus zu überleben, ist die ungewöhnlich hohe Widerstandsfähigkeit gegenüber freien Radikalen. Die wichtigste Quelle für freie Radikale bei der Abwehrreaktion des Wirtsorganismus ist Wasserstoffperoxid (H2O2 ). Es wird beim sogenannten „respiratory burst“ von Makrophagen freigesetzt, diffundiert dann durch biologische Membranen und schädigt DNA, Lipide und Proteine durch Zerfall in Sauerstoffradikale. Außerdem entsteht (H2O2 ) auch bei normalen Stoffwechselvorgängen in den Persoxisomen der Zelle. Das Enzym Katalase (EC 1.11.1.6) wandelt zweiWasserstoffperoxidmoleküle in Wasser und Sauerstoff um und eliminiert somit toxisches Wasserstoffperoxid. Katalase liegt zumeist in spezialisierten Zellorganellen, den Peroxisomen oder Microbodies, vor. Dort dient es zum Abbau von bei metabolischen Prozessen entstehendem Wasserstoffperoxid. Im Rahmen der vorliegenden Arbeit wurde die Katalase von Toxoplasma gondii kloniert und charakterisiert. Die Klonierung von T. gondii Katalase cDNA ergab ein Protein mit 502 Aminosäuren und einem errechneten Gewicht von 57.2 kDa mit starker Homologie zu anderen eukaryontischen Katalasen. Ein polyklonales Antiserum gegen ein GST-Fusionsprotein zeigte imWestern-blot eine Bande bei ungefähr 63 kDa. Die Immunfluoreszenz zeigte ein vesikuläres Kompartiment im vorderen Ende des Parasiten. Dieses kann von anderen Zellorganellen (Mikronemen, Rhoptrien, Granula densa und dem Apikoplast) durch doppelte Immunfluoreszenzmarkierung unterschieden werden. Zytochemisch können Katalasen durch die DAB-Präzipitationstechnik nachgewiesen werden. Hier zeigten sich vesikuläre Strukturen vor dem Nukleus in der Lichtmikroskopie und runde, spezifische Präzipitate mit einem Durchmesser von 100 bis 300nm in der Elektronenmikroskopie. Am C-terminus der T. gondii Katalase findet sich ein „peroxisomales Targeting Signal“ (PTS1) in den letzten 3 Aminosäuren (-AKM). Die Expression der vollständigen Katalase in CHO-Zellen resultiert in einer peroxisomalen Lokalisation, während ein Konstrukt ohne die letzten 3 Aminosäuren im Zytosol verbleibt. Wird das PTS1 mit einem Reporterprotein (Chloramphenicol-Acetyltransferase) fusioniert, wechselt dessen Lokalisation vom Zytosol zu den Peroxisomen. Damit wurde gezeigt, daß das PTS1 der T. gondii Katalase in einem heterologen System sowohl im Kontext der Katalase als auch eines Reporterproteins den Import in Peroxisomen vermitteln kann. Diese Ergebnisse sind die ersten Hinweise auf Peroxisomen in einem Parasiten der Apikomplexa. Zugleich ist T. gondii, evolutionsbiologisch gesehen, der bisher niedrigste Eukaryont in dem bisher Peroxisomen nachgewiesen wurden. N2 - Toxoplasma gondii is a unicellular parasite that is remarkably resistant to hydrogen peroxide. We cloned and sequenced the gene for T. gondii catalase (EC 1. 11.1.6), a peroxisomal marker enzyme in eukaryotes. The gene predicts a protein of about 57.2 kDa and 502 amino acids and has a strong homology to other eukaryotic catalases. By immunofluorescence T. gondii catalase is present primarily in a punctate staining pattern anterior to the parasite nucleus. This compartment can be distinguised from other parasite organelles, namely micronemes, rhoptries, dense granules, and the apicoplast. Cytochemical visualization of catalase using diaminobenzidine precipitation gives a vesicular staining pattern anterior to the nucleus at the light level and shows round structures with an estimated diameter of 100-300 nm by electron microscopy. T. gondii catalase exhibits a putative C-terminal peroxisomal targeting signal in the last 3 amino acids (-AKM). Expression of T. gondii catalase in a mammalian cell line results in peroxisomal localization, whereas a construct lacking the targeting signal remains in the cytosol. Furthermore, addition of -AKM to the C terminus of chloramphenicol acetyltransferase is sufficient to target this protein to peroxisomes. KW - Toxoplasma gondii KW - Katalase KW - Peroxisom KW - Toxoplasma gondii KW - catalase KW - peroxisome Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-6493 ER - TY - THES A1 - Merdanovic, Melisa T1 - Charakterisierung von NadR : das essentielle Enzym der NAD-Synthese bei Haemophilus influenzae T1 - Characterization of NadR: an essential enzyme of NAD synthesis in Haemophilus influenzae N2 - I Zusammenfassung Haemophilus influenzae, ein Gram-negatives, Bakterium der Familie Pasteurellaceae, kann beim Menschen eine Vielzahl an Erkrankungen auslösen: Die bekapselte Stämme, v. a. mit Typ b Kapsel können Cellulitis, septische Arthritis, Epiglottitis und Meningitis verursachen. Die nicht-bekapselte Stämme können Otitis media, Sinusitis, Pneumonie und in selteneren Fällen Bakterämie verursachen. Ein besonderes Merkmal des Metabolismus von H. influenzae ist dessen Unfähigkeit Nikotinamid-Adenin-Dinukleotid (NAD+) de novo zu synthetisieren. Daher sind die Enzyme bzw. Transporter, die an NAD+ Aufnahme und Resynthese beteiligt sind, als putative antimikrobielle Ziele von Interesse. In unserer Arbeitsgruppe konnte gezeigt werden, dass NAD+ zu Nikotinamidribosyl degradiert werden muss, bevor es in die Zelle aufgenommen werden kann. Auch Proteine, die an der Degradation des exogenen NAD+ zu Nikotinamidribosyl und dessen anschließender Aufnahme in die Zelle verantwortlich sind, konnten identifiziert und charakterisiert werden. Wie Nikotinamidribosyl im Cytoplasma wiederum zu NAD+ synthetisiert wird, ist auch erst kürzlich geklärt worden: für NadR konnte sowohl eine Ribosyl-Nukleotid-Kinase (RNK) Aktivität als auch eine Nikotinamid-Mononukleotid-Adenylyltransferase (NMNAT) Aktivität in vitro gezeigt werden. Die Kristallstruktur von hiNadR im Komplex mit NAD+ wurde auch aufgeklärt. In dieser Arbeit sollte NadR, insbesondere dessen RNK Domäne, in vivo und in vitro näher charakterisiert werden. Um zu untersuchen, ob beide Domänen in vivo essentiell sind, wurden Deletionsmutanten erzeugt, bei welchen die komplette bzw. der C-terminale Teil der RNK Domäne fehlten. Diese Deletionen konnten im nadV+ Hintergrund erzeugt werden. Die Deletionen konnten in H. influenzae nur zusammen mit dem nadV-Gen transferiert werden oder alternativ nur in die Zellen, die mit pNadRKan Plasmid transformiert wurden. Dies verdeutlicht, dass nicht nur die NMNAT Domäne sondern auch die RNK Domäne bzw. sogar nur wenige C-terminal fehlende Aminosäuren des NadR Proteins essentiell für die Lebensfähigkeit von H. influenzae sind. Gleichzeitig zeigen diese Experimente, dass die RNK-Domäne in Anwesenheit von NadV redundant ist. Ein weiterer Phänotyp der RNK-Deletionsmutante zeigte sich beim Nikotinamidribosyl-Transport. Im Gegensatz zum Wt, welcher ca. 60-80% des 14C-Nikotinamidribosyls aufnahm, konnte für die RNK-Deletionsmutante nur 2-5% Aufnahme gemessen werden. Dies konnte durch das pNadRKan Plasmid komplementiert werden. Weiterhin wurde festgestellt, dass spontan Aminopyridin-resistente H. influenzae Zellen Mutationen im nadR Gen haben, insbesondere im Walker A-Motif (P-Loop) der RNK Domäne. Zusätzlich konnte in dieser Arbeit gezeigt werden, dass NadR aus Aminopyridin und ATP Aminopyridin-Adenin-Dinukleotid synthetisieren kann. Somit konnte gezeigt werden, dass die wachstumshemmende Wirkung eigentlich durch das aus Aminopyridin synthetisierte Aminopyridin-Adenin-Dinukleotid entsteht, welches NAD+ in Redox-Reaktionen verdrängt, wodurch es letztendlich zum Stillstand des Metabolimus kommt. Durch Einführen von gezielten AS-Substitutionen im Walker A und B Motif und in der LID-Domäne von NadR, konnten einige Aminosäuren identifiziert werden, welche essentiell für die Aktivität der RNK Domäne sind. Alle Aminosäuren-Substitutionen führten zum Verlust der RNK Aktivität, die NMNAT Aktivität jedoch war nicht beeinträchtigt. Desweiteren wurden diese NadR Punktmutanten in vivo untersucht. Für alle konnte eine signifikante Defizienz in der Nikotinamidribosyl-Aufnahme beobachtet werden, die gemessene Aufnahme lag im Bereich der RNK-Deletionsmutante. Dadurch konnte eine direkte Korrelation zwischen der RNK Aktivität und der Nikotinamidribosyl-Aufnahme gezeigt werden. In weiteren in vitro Experimenten konnte für NadR eine Feedback-Inhibition durch das NAD+ gezeigt werden, wobei NAD+ in erster Linie die RNK Domäne von NadR inhibiert. Eine graduelle Erhöhung der NAD+ Konzentration führte in den in vitro Assays zu einer graduellen Abnahme der RNK. Bei der NMNAT Aktivität jedoch zeigte sich keine signifikante Inhibition in Anwesenheit von NAD+. Begleitende in vivo Experimente, zeigten eine 2/3 Reduktion der Nikotinamidribosyl-Aufnahme bei den Zellen, die mit NAD+ inkubiert wurden, d. h. höhere intrazelluläre NAD+ Konzentration hatten. Für die genauere Analyse der Feedback-Inhibition durch NAD+ wurden weitere Punktmutanen hergestellt. Bei zwei der Punktmutanten wurde eine Beeinträchtigung der NadR-Aktivität beobachtet, daher wurden diese Punktmutanten von weiteren Analysen im Bezug auf NAD+-Feedback Inhibition ausgeschlossen. Eine Mutante (NadRW256F) jedoch, zeigte ähnliche Aktivität wie das Wt-NadR. In Anwesenheit von NAD+ wurde die RNK Aktivität dieser Punktmutante, im Gegensatz zum Wt-Protein, kaum gehemmt. Dadurch konnte W256 als eine der Aminosäuren identifiziert werden, die an der Vermittlung der NAD+-bedingten Inhibition der RNK-Domäne beteiligt ist. N2 - I Summary Haemophilus influenzae, a gram-negative human pathogen belonging to a family of Pasteurellaceae is a causative agent of several distinct diseases. Whereas capsulated strains, particulary those with tybe b capsule can cause severe invasive infections such as cellulitis, septic arthrithis, epiglottitis and meningitis, non-capsulated strains generally tend to cause localized disease including otitis media, sinusitis, pneumonia and in rare cases bacteremia. The inability to synthesize NAD+ de novo is one of the hallmarks of H. influenzae metabolism, therefore proteins involved in NAD+ uptake and utilization respresent interesting putative targets for development of novel antimicrobial treatment. In our lab we were able to show, that prior to uptake, NAD+ has to be degraded to NR. Several proteins involved in NAD+ degradation and NR uptake were identified and characterized: OmpP2 (an outer-membrane porin), e(P4) (a membrane-bound acid phosphoesterase), NadN (a periplasmatic nucleotidase) and PnuC (a nicotinamidribosyl transporter localized in inner membrane). Enzyme responsible for resynthesis of nicotinamidribosyl to NAD+ was recently found to be NadR: A bifunctional protein containing a nicotinamidribosyl kinase (RNK) and a nicotinamid mononucleotide adenylyltransferase (NMNAT) activity, both of which were confirmed in vitro. Also, the crystal structure of NadR complexed with NAD+ was recently resolved. The aim of this work was to characterize the in vivo function of NadR, particular interest was laid on the characterization of the nicotinamidribosyl kinase domain. To test if both domains of NadR are essential for survival, deletion mutants lacking the entire RNK domain and the C-terminal 58 amino acids were constructed. Initially, these mutants were made in a H. influenzae strain which contains a chromosomal copy of H. ducreyi nadV gene. In following transformation experiments, transfer of the RNK deletion mutants to H. influenzae strain was always accompanied with an nadV transfer as well. Only in strain containing pNadRKan plasmid, no nadV transfer along with RNK-deletions took place. Indirectly, this shows that not only the entire RNK domain is essential for H. influenzae, but also the last 58 amino acids as well. It also shows that in presence of NadV the RNK domain is redundant. RNK deletion mutant displayed a significant deficiency in nicotinamidribosyl transport as well: whereas the Wt strain can accumulate up to 80% of 14C labeled nicotinamidribosyl, RNK mutant is able to accumulate only 2-5%. Introduction of pNadRKan plasmid to RNK mutant restored transport efficiency to Wt level. Studies using spontanous 3-aminopyridine (3-AmPR) resistant H. influenzae isolates, revealed that almost all 3-AmPR resistant isolates have mutations in the nadR gene. A clustering of mutations in Walker A motif of the RNK domain could be observed. Further studies represented in this work, show that 3-AmPR can act as a subtrate for NadR, therefore in ATP consuming reactions aminopyridine-adenindinucleotide can be synthesized. Intracellular aminopyridine-adenindinucleotide replaces NAD+ in redox reactions, which ultimately leads to inhibition of cell metabolism, thereby explaining the mechanism of 3-AmPR based growth inhibition. Using site-directed mutagenesis to introduce amino acid substitutions in distinct parts of the NadR-RNK domain, active sites of the RNK domain were revealed and amino acids essential for the RNK activity were identified. These defined amino acid exchanges resulted in loss of the RNK activity in vitro, but had no effect on the NMNAT activity, which remained intact in these mutant variants of NadR. Following in vivo studies revealed that all mutant NadR proteins caused a severe nicotinamidribosyl uptake deficiency, similar to the one observed in the RNK deletion mutant. Therefore, a direct correlation between the RNK activity and nicotinamidribosyl uptake was shown. Further in vitro studies revealed a feedback inhibition of NadR by NAD+, especially for the RNK domain. In case of RNK domain a gradual increase of NAD+ concentration led to gradual decrease in RNK activity. In contrast, for NMNAT domain no significant inhibition in the presence of NAD+ was observed. Also, in in vivo experiments a 3 fold reduction of nicotinamidribosyl uptake rate was observed when intracellular NAD+ concentrations were higher. To adress the mechanism of NAD+ feedback inhibition, once again, distinct amino acid exchanges were introduced. In vitro, two of the mutant proteins were impaired in their activity, especially if lower protein contrations were used. Therefore, further test concerning inhibtion were not preformed with these mutants. However, a W256F protein displayed activity similar to that of the native protein and furthermore was not inhibited in presence of NAD+. This indicates an involvement of the amino acid W256 in mediating the NAD+ dependent feedback inhibition on NadR activity. KW - Haemophilus influenzae KW - NAD KW - Synthese KW - NAD KW - Enzym KW - Synthese KW - Haemophilus KW - influenzae KW - NAD KW - enzyme KW - synthesis KW - Haemophilus KW - influenzae Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-14907 ER - TY - THES A1 - Quittnat, Friederike Susanne T1 - Cholesterinmetabolismus in Toxoplasma gondii : Klonierung und Nachweis der Funktion eines Acyl-CoA: Cholesterin Acyltransferase aehnlichen Enzyms - ein neuer Angriffspunkt fuer pharmakologische Intervention T1 - Cholesterolmetabolism in Toxoplasma gondii: cloning and function of an ACAT-like enzyme - a new target for pharmacological intervention N2 - Ich praesentiere hier die Klonierung und Funktion eines ACAT-aehnlichen Enzyms von Toxoplasma gondii (T. gondii), das lebensnotwendig fuer T. gondii zu sein scheint. Medikamente, die gegen die menschliche ACAT gerichtet sind, erhoehen in geringen Konzentrationen die ACAT-Aktivitaet von T. gondii. In hoeheren Konzentrationen schraenken sie jedoch die Vitalitaet von T. gondii ein. N2 - Here I present the cloning and functional analysis of a Toxoplasma gondii (T. gondii) ACAT-like enzyme required for its viability. Drugs directed against the human ACAT when used at a low concentration increase the activity of the T. gondii ACAT. However when used at higher concentrations the vitality of T. gondii is reduced. KW - Toxoplasma gondii KW - Cholesterin KW - Neutrallipide KW - ACAT KW - Toxoplasma gondii KW - cholesterol KW - neutrallipids KW - ACAT Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-13965 ER - TY - JOUR A1 - Beck, Christine A1 - Morbach, Henner A1 - Beer, Meinrad A1 - Stenzel, Martin A1 - Tappe, Dennis A1 - Gattenlöhner, Stefan A1 - Hofmann, Ulrich A1 - Raab, Peter A1 - Girschick, Hermann J. T1 - Chronic nonbacterial osteomyelitis in childhood: prospective follow-up during the first year of anti-inflammatory treatment N2 - Introduction: Chronic nonbacterial osteomyelitis (CNO) is an inflammatory disorder of unknown etiology. In children and adolescents CNO predominantly affects the metaphyses of the long bones, but lesions can occur at any site of the skeleton. Prospectively followed cohorts using a standardized protocol in diagnosis and treatment have rarely been reported. Methods: Thirty-seven children diagnosed with CNO were treated with naproxen continuously for the first 6 months. If assessment at that time revealed progressive disease or no further improvement, sulfasalazine and short-term corticosteroids were added. The aims of our short-term follow-up study were to describe treatment response in detail and to identify potential risk factors for an unfavorable outcome. Results: Naproxen treatment was highly effective in general, inducing a symptom-free status in 43% of our patients after 6 months. However, four nonsteroidal anti-inflammatory drug (NSAID) partial-responders were additionally treated with sulfasalazine and short-term corticosteroids. The total number of clinical detectable lesions was significantly reduced. Mean disease activity estimated by the patient/physician and the physical aspect of health-related quality of life including functional ability (global assessment/childhood health assessment questionnaire and childhood health assessment questionnaire) and pain improved significantly. Forty-one percent of our patients showed radiological relapses, but 67% of them were clinically silent. Conclusions: Most children show a favorable clinical course in the first year of anti-inflammatory treatment with NSAIDs. Relapses and new radiological lesions can occur at any time and at any site in the skeleton but may not be clinically symptomatic. Whole-body magnetic resonance imaging proved to be very sensitive for initial and follow-up diagnostics. KW - Mikrobiologie Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67792 ER - TY - JOUR A1 - Cucher, Marcela A. A1 - Mariconti, Mara A1 - Manciulli, Tommaso A1 - Vola, Ambra A1 - Rosenzvit, Mara C. A1 - Brehm, Klaus A1 - Kamenetzky, Laura A1 - Brunetti, Enrico T1 - Circulating small RNA profiling of patients with alveolar and cystic echinococcosis JF - Biology N2 - Alveolar (AE) and cystic (CE) echinococcosis are two parasitic diseases caused by the tapeworms Echinococcus multilocularis and E. granulosus sensu lato (s. l.), respectively. Currently, AE and CE are mainly diagnosed by means of imaging techniques, serology, and clinical and epidemiological data. However, no viability markers that indicate parasite state during infection are available. Extracellular small RNAs (sRNAs) are short non-coding RNAs that can be secreted by cells through association with extracellular vesicles, proteins, or lipoproteins. Circulating sRNAs can show altered expression in pathological states; hence, they are intensively studied as biomarkers for several diseases. Here, we profiled the sRNA transcriptomes of AE and CE patients to identify novel biomarkers to aid in medical decisions when current diagnostic procedures are inconclusive. For this, endogenous and parasitic sRNAs were analyzed by sRNA sequencing in serum from disease negative, positive, and treated patients and patients harboring a non-parasitic lesion. Consequently, 20 differentially expressed sRNAs associated with AE, CE, and/or non-parasitic lesion were identified. Our results represent an in-depth characterization of the effect E. multilocularis and E. granulosus s. l. exert on the extracellular sRNA landscape in human infections and provide a set of novel candidate biomarkers for both AE and CE detection. KW - echinococcosis KW - small RNA KW - extracellular KW - circulating KW - microRNA KW - serum KW - tapeworm KW - diagnosis KW - marker KW - Echinococcus Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-319270 SN - 2079-7737 VL - 12 IS - 5 ER - TY - JOUR A1 - Peters, Simon A1 - Kaiser, Lena A1 - Fink, Julian A1 - Schumacher, Fabian A1 - Perschin, Veronika A1 - Schlegel, Jan A1 - Sauer, Markus A1 - Stigloher, Christian A1 - Kleuser, Burkhard A1 - Seibel, Juergen A1 - Schubert-Unkmeir, Alexandra T1 - Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria JF - Scientific Reports N2 - Sphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce 'click-AT-CLEM', a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity. KW - antimicrobials KW - biological techniques KW - imaging KW - microbiology KW - microbiology techniques KW - microscopy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259147 VL - 11 IS - 1 ER - TY - JOUR A1 - Abimannan, Nagarajan A1 - Sumathi, G. A1 - Krishnarajasekhar, O. R. A1 - Sinha, Bhanu A1 - Krishnan, Padma T1 - Clonal Clusters and Virulence Factors of Methicillin-Resistant \(Staphylococcus\) \(Aureus\): Evidence for Community-Acquired Methicillin-Resistant \(Staphylococcus\) \(Aureus\) Infiltration into Hospital Settings in Chennai, South India JF - Indian Journal of Medical Microbiology N2 - Background and Objective: Staphylococcus aureus is one of the major pathogens of nosocomial infections as wells as community-acquired (CA) infections worldwide. So far, large-scale comprehensive molecular and epidemiological characterisation of S. aureus from very diverse settings has not been carried out in India. The objective of this study is to evaluate the molecular, epidemiological and virulence characteristics of S. aureus in both community and hospital settings in Chennai, southern India. Methods: S. aureus isolates were obtained from four different groups (a) healthy individuals from closed community settings, (b) inpatients from hospitals, (c) outpatients from hospitals, representing isolates of hospital-community interface and (d) HIV-infected patients to define isolates associated with the immunocompromised. Antibiotic susceptibility testing, multiplex polymerase chain reactions for detection of virulence and resistance determinants, molecular typing including Staphylococcal cassette chromosome mec (SCCmec) and agr typing, were carried out. Sequencing-based typing was done using spa and multilocus sequence typing (MLST) methods. Clonal complexes (CC) of hospital and CA methicillin-resistant S. aureus (MRSA) were identified and compared for virulence and resistance. Results and Conclusion: A total of 769 isolates of S. aureus isolates were studied. The prevalence of MRSA was found to be 7.17%, 81.67%, 58.33% and 22.85% for groups a, b, c and d, respectively. Of the four SCCmec types (I, III, IV and V) detected, SCCmec V was found to be predominant. Panton-Valentine leucocidin toxin genes were detected among MRSA isolates harbouring SCCmec IV and V. A total of 78 spa types were detected, t657 being the most prevalent. 13 MLST types belonging to 9 CC were detected. CC1 (ST-772, ST-1) and CC8 (ST238, ST368 and ST1208) were found to be predominant among MRSA. CA-MRSA isolates with SCCmec IV and V were isolated from all study groups including hospitalised patients and were found to be similar by molecular tools. This shows that CA MRSA has probably infiltrated into the hospital settings. KW - Community-acquired methicillin-resistant Staphylococcus aureus KW - HIV KW - hospital-acquired methicillin-resistant Staphylococcus aureus KW - innate immune evasions KW - MLST KW - microbial surface component recognising adhesive matrix molecules KW - spa typing KW - ST 772 KW - Inducible Clindamycin Resistance KW - Valentine Leukocidin Genes KW - Multiplex PCR KW - Nasal Carriage KW - Colonization KW - Prevalence KW - Emergence KW - Skin Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226963 VL - 37 IS - 3 ER - TY - JOUR A1 - Koziol, Uriel A1 - Jarero, Francesca A1 - Olson, Peter D. A1 - Brehm, Klaus T1 - Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms JF - BMC Biology N2 - Background Early developmental patterns of flatworms are extremely diverse and difficult to compare between distant groups. In parasitic flatworms, such as tapeworms, this is confounded by highly derived life cycles involving indirect development, and even the true orientation of the tapeworm antero-posterior (AP) axis has been a matter of controversy. In planarians, and metazoans generally, the AP axis is specified by the canonical Wnt pathway, and we hypothesized that it could also underpin axial formation during larval metamorphosis in tapeworms. Results By comparative gene expression analysis of Wnt components and conserved AP markers in the tapeworms Echinococcus multilocularis and Hymenolepis microstoma, we found remarkable similarities between the early stages of larval metamorphosis in tapeworms and late embryonic and adult development in planarians. We demonstrate posterior expression of specific Wnt factors during larval metamorphosis and show that scolex formation is preceded by localized expression of Wnt inhibitors. In the highly derived larval form of E. multilocularis, which proliferates asexually within the mammalian host, we found ubiquitous expression of posterior Wnt factors combined with localized expression of Wnt inhibitors that correlates with the asexual budding of scoleces. As in planarians, muscle cells are shown to be a source of secreted Wnt ligands, providing an explanation for the retention of a muscle layer in the immotile E. multilocularis larva. Conclusions The strong conservation of gene expression between larval metamorphosis in tapeworms and late embryonic development in planarians suggests, for the first time, a homologous developmental period across this diverse phylum. We postulate these to represent the phylotypic stages of these flatworm groups. Our results support the classical notion that the scolex is the true anterior end of tapeworms. Furthermore, the up-regulation of Wnt inhibitors during the specification of multiple anterior poles suggests a mechanism for the unique asexual reproduction of E. multilocularis larvae. KW - antero-posterior axis KW - FoxQ2 KW - myocyte KW - planarian KW - SFRP KW - cestodes KW - metamorphosis KW - phylotypic KW - platyhelminthes KW - Six3/6 Wnt Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146566 VL - 14 IS - 10 ER - TY - JOUR A1 - Klughammer, Johanna A1 - Dittrich, Marcus A1 - Blom, Jochen A1 - Mitesser, Vera A1 - Vogel, Ulrich A1 - Frosch, Matthias A1 - Goesmann, Alexander A1 - Müller, Tobias A1 - Schoen, Christoph T1 - Comparative genome sequencing reveals within-host genetic changes in Neisseria meningitidis during invasive disease JF - PLoS ONE N2 - Some members of the physiological human microbiome occasionally cause life-threatening disease even in immunocompetent individuals. A prime example of such a commensal pathogen is Neisseria meningitidis, which normally resides in the human nasopharynx but is also a leading cause of sepsis and epidemic meningitis. Using N. meningitidis as model organism, we tested the hypothesis that virulence of commensal pathogens is a consequence of within host evolution and selection of invasive variants due to mutations at contingency genes, a mechanism called phase variation. In line with the hypothesis that phase variation evolved as an adaptation to colonize diverse hosts, computational comparisons of all 27 to date completely sequenced and annotated meningococcal genomes retrieved from public databases showed that contingency genes are indeed enriched for genes involved in host interactions. To assess within-host genetic changes in meningococci, we further used ultra-deep whole-genome sequencing of throat-blood strain pairs isolated from four patients suffering from invasive meningococcal disease. We detected up to three mutations per strain pair, affecting predominantly contingency genes involved in type IV pilus biogenesis. However, there was not a single (set) of mutation(s) that could invariably be found in all four pairs of strains. Phenotypic assays further showed that these genetic changes were generally not associated with increased serum resistance, higher fitness in human blood ex vivo or differences in the interaction with human epithelial and endothelial cells in vitro. In conclusion, we hypothesize that virulence of meningococci results from accidental emergence of invasive variants during carriage and without within host evolution of invasive phenotypes during disease progression in vivo. KW - blood KW - comparative genomics KW - throat KW - genetic loci KW - Neisseria meningitidis KW - genomic libraries KW - genome sequencing KW - sequence assembly tools Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159547 VL - 12 IS - 1 ER - TY - JOUR A1 - Sattler, Janko A1 - Noster, Janina A1 - Brunke, Anne A1 - Plum, Georg A1 - Wiegel, Pia A1 - Kurzai, Oliver A1 - Meis, Jacques F. A1 - Hamprecht, Axel T1 - Comparison of two commercially available qPCR kits for the detection of Candida auris JF - Journal of Fungi N2 - Candida auris is an emerging pathogen with resistance to many commonly used antifungal agents. Infections with C. auris require rapid and reliable detection methods to initiate successful medical treatment and contain hospital outbreaks. Conventional identification methods are prone to errors and can lead to misidentifications. PCR-based assays, in turn, can provide reliable results with low turnaround times. However, only limited data are available on the performance of commercially available assays for C. auris detection. In the present study, the two commercially available PCR assays AurisID (OLM, Newcastle Upon Tyne, UK) and Fungiplex Candida Auris RUO Real-Time PCR (Bruker, Bremen, Germany) were challenged with 29 C. auris isolates from all five clades and eight other Candida species as controls. AurisID reliably detected C. auris with a limit of detection (LoD) of 1 genome copies/reaction. However, false positive results were obtained with high DNA amounts of the closely related species C. haemulonii, C. duobushaemulonii and C. pseudohaemulonii. The Fungiplex Candida Auris RUO Real-Time PCR kit detected C. auris with an LoD of 9 copies/reaction. No false positive results were obtained with this assay. In addition, C. auris could also be detected in human blood samples spiked with pure fungal cultures by both kits. In summary, both kits could detect C. auris-DNA at low DNA concentrations but differed slightly in their limits of detection and specificity. KW - qPCR KW - detection limits KW - sensitivity KW - strain specificity KW - commercial kits KW - Candida auris KW - Fungiplex Candida Auris KW - AurisID Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228879 SN - 2309-608X VL - 7 IS - 2 ER - TY - JOUR A1 - Dichtl, Karl A1 - Forster, Johannes A1 - Ormanns, Steffen A1 - Horns, Heidi A1 - Suerbaum, Sebastian A1 - Seybold, Ulrich A1 - Wagener, Johannes T1 - Comparison of β-D-Glucan and galactomannan in serum for detection of invasive aspergillosis: retrospective analysis with focus on early diagnosis JF - Journal of Fungi N2 - The early diagnosis of invasive aspergillosis (IA) relies mainly on computed tomography imaging and testing for fungal biomarkers such as galactomannan (GM). We compared an established ELISA for the detection of GM with a turbidimetric assay for detection of the panfungal biomarker β-D-glucan (BDG) for early diagnosis of IA. A total of 226 serum specimens from 47 proven and seven probable IA cases were analysed. Sensitivity was calculated for samples obtained closest to the day of IA-diagnosis (d0). Additional analyses were performed by including samples obtained during the presumed course of disease. Most IA cases involved the respiratory system (63%), and Aspergillus fumigatus was the most frequently isolated species (59%). For proven cases, sensitivity of BDG/GM analysis was 57%/40%. Including all samples dating from –6 to +1 weeks from d0 increased sensitivities to 74%/51%. Sensitivity of BDG testing was as high as or higher than GM testing for all subgroups and time intervals analysed. BDG testing was less specific (90–93%) than GM testing (99–100%). Combining BDG and GM testing resulted in sensitivity/specificity of 70%/91%. Often, BDG testing was positive before GM testing. Our study backs the use of BDG for diagnosis of suspected IA. We suggest combining BDG and GM to improve the overall sensitivity. KW - BDG KW - beta-D-glucan KW - GM KW - galactomannan KW - IA KW - invasive aspergillosis KW - biomarker KW - fungal antigens KW - serology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216298 SN - 2309-608X VL - 6 IS - 4 ER - TY - JOUR A1 - Herrmann, Johannes A1 - Muenstermann, Marcel A1 - Strobel, Lea A1 - Schubert-Unkmeir, Alexandra A1 - Woodruff, Trent M. A1 - Gray-Owen, Scott D. A1 - Klos, Andreas A1 - Johswich, Kay O. T1 - Complement C5a receptor 1 exacerbates the pathophysiology of N. meningitidis sepsis and is a potential target for disease treatment JF - mBio N2 - Sepsis caused by Neisseria meningitidis (meningococcus) is a rapidly progressing, life-threatening disease. Because its initial symptoms are rather unspecific, medical attention is often sought too late, i.e., when the systemic inflammatory response is already unleashed. This in turn limits the success of antibiotic treatment. The complement system is generally accepted as the most important innate immune determinant against invasive meningococcal disease since it protects the host through the bactericidal membrane attack complex. However, complement activation concomitantly liberates the C5a peptide, and it remains unclear whether this potent anaphylatoxin contributes to protection and/or drives the rapidly progressing immunopathogenesis associated with meningococcal disease. Here, we dissected the specific contribution of C5a receptor 1 (C5aR1), the canonical receptor for C5a, using a mouse model of meningococcal sepsis. Mice lacking C3 or C5 displayed susceptibility that was enhanced by >1,000-fold or 100-fold, respectively, consistent with the contribution of these components to protection. In clear contrast, C5ar1\(^{-/-}\) mice resisted invasive meningococcal infection and cleared N. meningitidis more rapidly than wild-type (WT) animals. This favorable outcome stemmed from an ameliorated inflammatory cytokine response to N. meningitidis in C5ar1\(^{-/-}\) mice in both in vivo and ex vivo whole-blood infections. In addition, inhibition of C5aR1 signaling without interference with the complement bactericidal activity reduced the inflammatory response also in human whole blood. Enticingly, pharmacologic C5aR1 blockade enhanced mouse survival and lowered meningococcal burden even when the treatment was administered after sepsis induction. Together, our findings demonstrate that C5aR1 drives the pathophysiology associated with meningococcal sepsis and provides a promising target for adjunctive therapy. Importance: The devastating consequences of N. meningitidis sepsis arise due to the rapidly arising and self-propagating inflammatory response that mobilizes antibacterial defenses but also drives the immunopathology associated with meningococcemia. The complement cascade provides innate broad-spectrum protection against infection by directly damaging the envelope of pathogenic microbes through the membrane attack complex and triggers an inflammatory response via the C5a peptide and its receptor C5aR1 aimed at mobilizing cellular effectors of immunity. Here, we consider the potential of separating the bactericidal activities of the complement cascade from its immune activating function to improve outcome of N. meningitidis sepsis. Our findings demonstrate that the specific genetic or pharmacological disruption of C5aR1 rapidly ameliorates disease by suppressing the pathogenic inflammatory response and, surprisingly, allows faster clearance of the bacterial infection. This outcome provides a clear demonstration of the therapeutic benefit of the use of C5aR1-specific inhibitors to improve the outcome of invasive meningococcal disease. KW - C5aR1 KW - whole-blood model KW - Neisseria meningitidis KW - anaphylatoxins KW - complement system KW - inflammation KW - invasive disease KW - mouse model KW - neutrophils KW - sepsis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175792 VL - 9 IS - 1 ER - TY - JOUR A1 - Fraunholz, Martin A1 - Bernhardt, Jörg A1 - Schuldes, Jörg A1 - Daniel, Rolf A1 - Hecker, Michael A1 - Sinh, Bhanu T1 - Complete Genome Sequence of Staphylococcus aureus 6850, a Highly Cytotoxic and Clinically Virulent Methicillin-Sensitive Strain with Distant Relatedness to Prototype Strains JF - Genome Announcements N2 - Staphylococcus aureus is a frequent human commensal bacterium and pathogen. Here we report the complete genome sequence of strain 6850 (spa type t185; sequence type 50 [ST50]), a highly cytotoxic and clinically virulent methicillin-sensitive strain from a patient with complicated S. aureus bacteremia associated with osteomyelitis and septic arthritis. KW - gen Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129294 VL - 1 IS - 5 ER - TY - JOUR A1 - Beierle, Felix A1 - Schobel, Johannes A1 - Vogel, Carsten A1 - Allgaier, Johannes A1 - Mulansky, Lena A1 - Haug, Fabian A1 - Haug, Julian A1 - Schlee, Winfried A1 - Holfelder, Marc A1 - Stach, Michael A1 - Schickler, Marc A1 - Baumeister, Harald A1 - Cohrdes, Caroline A1 - Deckert, Jürgen A1 - Deserno, Lorenz A1 - Edler, Johanna-Sophie A1 - Eichner, Felizitas A. A1 - Greger, Helmut A1 - Hein, Grit A1 - Heuschmann, Peter A1 - John, Dennis A1 - Kestler, Hans A. A1 - Krefting, Dagmar A1 - Langguth, Berthold A1 - Meybohm, Patrick A1 - Probst, Thomas A1 - Reichert, Manfred A1 - Romanos, Marcel A1 - Störk, Stefan A1 - Terhorst, Yannik A1 - Weiß, Martin A1 - Pryss, Rüdiger T1 - Corona Health — A Study- and Sensor-Based Mobile App Platform Exploring Aspects of the COVID-19 Pandemic JF - International Journal of Environmental Research and Public Health N2 - Physical and mental well-being during the COVID-19 pandemic is typically assessed via surveys, which might make it difficult to conduct longitudinal studies and might lead to data suffering from recall bias. Ecological momentary assessment (EMA) driven smartphone apps can help alleviate such issues, allowing for in situ recordings. Implementing such an app is not trivial, necessitates strict regulatory and legal requirements, and requires short development cycles to appropriately react to abrupt changes in the pandemic. Based on an existing app framework, we developed Corona Health, an app that serves as a platform for deploying questionnaire-based studies in combination with recordings of mobile sensors. In this paper, we present the technical details of Corona Health and provide first insights into the collected data. Through collaborative efforts from experts from public health, medicine, psychology, and computer science, we released Corona Health publicly on Google Play and the Apple App Store (in July 2020) in eight languages and attracted 7290 installations so far. Currently, five studies related to physical and mental well-being are deployed and 17,241 questionnaires have been filled out. Corona Health proves to be a viable tool for conducting research related to the COVID-19 pandemic and can serve as a blueprint for future EMA-based studies. The data we collected will substantially improve our knowledge on mental and physical health states, traits and trajectories as well as its risk and protective factors over the course of the COVID-19 pandemic and its diverse prevention measures. KW - mobile health KW - ecological momentary assessment KW - digital phenotyping KW - longitudinal studies KW - mobile crowdsensing Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242658 SN - 1660-4601 VL - 18 IS - 14 ER - TY - JOUR A1 - Tappe, Beeke A1 - Lauruschkat, Chris D. A1 - Strobel, Lea A1 - Pantaleón García, Jezreel A1 - Kurzai, Oliver A1 - Rebhan, Silke A1 - Kraus, Sabrina A1 - Pfeuffer-Jovic, Elena A1 - Bussemer, Lydia A1 - Possler, Lotte A1 - Held, Matthias A1 - Hünniger, Kerstin A1 - Kniemeyer, Olaf A1 - Schäuble, Sascha A1 - Brakhage, Axel A. A1 - Panagiotou, Gianni A1 - White, P. Lewis A1 - Einsele, Hermann A1 - Löffler, Jürgen A1 - Wurster, Sebastian T1 - COVID-19 patients share common, corticosteroid-independent features of impaired host immunity to pathogenic molds JF - Frontiers in Immunology N2 - Patients suffering from coronavirus disease-2019 (COVID-19) are susceptible to deadly secondary fungal infections such as COVID-19-associated pulmonary aspergillosis and COVID-19-associated mucormycosis. Despite this clinical observation, direct experimental evidence for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-driven alterations of antifungal immunity is scarce. Using an ex-vivo whole blood stimulation assay, we challenged blood from twelve COVID-19 patients with Aspergillus fumigatus and Rhizopus arrhizus antigens and studied the expression of activation, maturation, and exhaustion markers, as well as cytokine secretion. Compared to healthy controls, T-helper cells from COVID-19 patients displayed increased expression levels of the exhaustion marker PD-1 and weakened A. fumigatus- and R. arrhizus-induced activation. While baseline secretion of proinflammatory cytokines was massively elevated, whole blood from COVID-19 patients elicited diminished release of T-cellular (e.g., IFN-γ, IL-2) and innate immune cell-derived (e.g., CXCL9, CXCL10) cytokines in response to A. fumigatus and R. arrhizus antigens. Additionally, samples from COVID-19 patients showed deficient granulocyte activation by mold antigens and reduced fungal killing capacity of neutrophils. These features of weakened anti-mold immune responses were largely decoupled from COVID-19 severity, the time elapsed since diagnosis of COVID-19, and recent corticosteroid uptake, suggesting that impaired anti-mold defense is a common denominator of the underlying SARS-CoV-2 infection. Taken together, these results expand our understanding of the immune predisposition to post-viral mold infections and could inform future studies of immunotherapeutic strategies to prevent and treat fungal superinfections in COVID-19 patients. KW - COVID-19 KW - immune impairment KW - T cells KW - granulocytes KW - Aspergillus KW - Rhizopus Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-283558 SN - 1664-3224 VL - 13 ER - TY - JOUR A1 - Geyer, Kathrin K. A1 - Chalmers, Iain W. A1 - MacKintosh, Neil A1 - Hirst, Julie E. A1 - Geoghegan, Rory A1 - Badets, Mathieu A1 - Brophy, Peter M. A1 - Brehm, Klaus A1 - Hoffmann, Karl F. T1 - Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes JF - BMC Genomics N2 - Background: The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results: Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and 'Turbellaria') contain methylated cytosines within their genome compartments. Conclusions: Collectively, these findings provide the first direct evidence for a functionally conserved and enzymatically active DNA methylation system throughout the Platyhelminthes. Defining how this epigenetic feature shapes phenotypic diversity and development within the phylum represents an exciting new area of metazoan biology. KW - methyltransferase homolog KW - echinococcus multilocularis KW - platyhelminthes KW - 5-methyl cytosine KW - gene KW - proteins KW - stem cells KW - maximum liklihood KW - schistoma mansoni KW - flatworm KW - CPG binding domain KW - DNA methylation KW - epgenetics KW - complex Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121892 SN - 1471-2164 VL - 14 IS - 462 ER - TY - THES A1 - Halscheidt, Anja T1 - Das RpoS-Protein aus Vibrio cholerae : Funktionsanalyse und Charakterisierung der Proteolyse-Kaskade T1 - The RpoS protein of Vibrio cholerae : Functional analysis and characterization of the proteolysis cascade N2 - In der vorliegenden Arbeit wurde zunächst die Konservierung bekannter RpoS-assoziierter Funktionen für das V. cholerae Homolog untersucht. Dabei ergab die phänotypische Analyse der rpoS-Deletionsmutante, dass analog zu der Bedeutung als Regulator des Stationärphasen-Wachstums in E. coli, definierte Zelldichte-abhängige Eigenschaften in V. cholerae gleichermaßen der Kontrolle von RpoS unterliegen. In weiterführenden Experimenten konnte daraufhin die Konservierung der entsprechenden Promotorstrukturen über die funktionelle Komplementierung rpoS-abhängiger Gene durch das jeweils speziesfremde Protein aufgedeckt werden. Dahingegen konnte die Bedeutung von RpoS bei der Ausprägung der generellen Stress-Resistenz u. a. in E. coli für das V. cholerae Homolog über den gewählten experimentellen Ansatz nicht belegt werden. So wurden in Survival-Assays für keine der getesteten Stress-Bedingungen signifikante Unterschiede zwischen rpoS-Mutante und Wildtyp ermittelt. Die in E. coli gezeigte intrazelluläre Anreicherung des Sigmafaktors unter diversen Stress-Situationen konnte ebenfalls nicht nachgewiesen werden. Hinsichtlich der potentiellen Stellung von RpoS als globaler Regulator für Virulenz-assoziierte Gene, unterstützen und ergänzen die Ergebnisse der vorliegenden Arbeit die gegenwärtige Theorie, wonach RpoS das Ablösen der V. cholerae Zellen vom Darm-Epithel fördert. Die postulierte Bedeutung des alternativen Sigmafaktors in der letzten Phase der Pathogenese wurde über die RpoS-abhängige Sekretion der Mukin-degradierenden Protease HapA und die hier unabhängig nachgewiesene Transkriptionskontrolle von Chemotaxis-Genen bestätigt. In E. coli gilt als entscheidender Parameter für die dargelegten RpoS-Funktionen die intrazelluläre Konzentration des Masterregulators. Deshalb war ein weiteres zentrales Thema dieser Arbeit die Regulation des RpoS-Levels in V. cholerae. Neben der Identifizierung von Bedingungen, welche die RpoS-Expression beeinflussen, wurde vorrangig der Mechanismus der Proteolyse analysiert. Dabei wurden als RpoS-degradierende Komponenten in V. cholerae die Homologe des Proteolyse-Targetingfaktors RssB und des Protease-Komplexes ClpXP identifiziert. Die weitere Untersuchung der RpoS-Proteolyse ergab außerdem, dass bestimmte Stress-Signale den Abbau stark verzögern. Interessanterweise resultierten die gleichen Signale jedoch nicht in der Akkumulation von RpoS. Als weiterer Unterschied zu der bekannten Proteolysekaskade in E. coli zeigte sich, dass das V. cholerae Homolog der RssB-aktivierenden Kinase ArcB (FexB) an der RpoS-Proteolyse nicht beteiligt ist. Indessen deuten die Ergebnisse weiterführender Experimente auf den Einfluss der Kinasen CheA-1 und CheA-3 des V. cholerae Chemotaxis-Systems auf die RpoS-Degradation. Aus diesem Grund wurde in der vorliegenden Arbeit ein zu E. coli abweichendes Modell der RpoS-Proteolyse postuliert, in welchem die aktiven CheA-Kinasen den Targetingfaktor RssB phosphorylieren und somit den Abbau einleiten. Die Beteiligung von MCP-Rezeptoren an der Kontrolle der intrazellulären RpoS-Konzentration und damit an der Transkription der Chemotaxisgene selbst, beschreibt erstmalig ein Regulationssystem, wonach innerhalb der Chemotaxis-Kaskade die Rezeptoraktivität wahrscheinlich über einen positiven „Feedback-Loop“ mit der eigenen Gen-Expression gekoppelt ist. Darüber hinaus deutete sich die Beteiligung der ATP-abhängigen Protease Lon an der RpoS-Proteolyse-Kaskade in V. cholerae an. Die Inaktivierung der in E. coli unter Hitzeschock-Bedingungen induzierten Protease resultierte in einem extrem beschleunigten RpoS-Abbau. Ein letztes Teilprojekt dieser Arbeit adressierte die Regulationsmechanismen der V. cholerae Osmostress-Adaptation. Während in E. coli der alternative Sigmafaktor dabei eine zentrale Rolle spielt, konnte die Beteiligung des V. cholerae RpoS an der Osmostress-Regulation jedoch nicht aufgedeckt werden. Dafür ergab die Funktionsanalyse eines neu definierten Osmostress-Sensors (OsmRK) die Kontrolle von ompU durch dieses Zwei-Komponentensystems unter hypertonen Bedingungen. Dieses Ergebnis überraschte, da bislang nur der Virulenzfaktor ToxR als Regulator für das Außenmembranporin beschrieben wurde. Die nachgewiesene ompU-Transkriptionskontrolle durch zwei Regulatoren führte zu der Hypothese eines unbekannten regulativen Netzwerkes, welchem mindestens 52 weitere Gene zugeordnet werden konnten. Insgesamt ist festzuhalten, dass die in dieser Arbeit durchgeführte molekulare Charakterisierung der RpoS-Proteolyse in V. cholerae Beweise für eine mögliche Verbindung zwischen der Transkriptionskontrolle für Motilitäts- und Chemotaxisgene mit der Chemotaxis-Reizwahrnehmung erbrachte. Eine derartige intermolekulare Verknüpfung wurde bislang für keinen anderen Organismus beschrieben und stellt somit eine neue Variante der Signaltransduktion innerhalb der Virulenz-assoziierten Genregulation dar. N2 - In the present work conserved function of RpoS in E. coli was approached for its homolog in V. cholerae. Comprehensive phenotypical analysis of rpoS-mutant and wildtype revealed the involvement of RpoS in growth-phase-dependent processes, according to RpoS-function as stationary phase regulator in E. coli. In further experiments the conservation of RpoS-promoters in both species could be shown. To the contrary, the well-known function of E. coli RpoS as general stress-regulator could not be demonstrate for V. cholerae: By testing several stress conditions in survival assays, no significant differences were determined between rpoS mutant and wildtype. Additionally, the intracellular mode of RpoS accumulation in E. coli due to different stress conditions was also not observed in V. cholerae. Regarding the putative role of RpoS as a regulator for virulence-associated genes, the inhere described data support and complement the current theory of RpoS being involved in mucosal detachment of V. cholerae cells. In E. coli the intracellular concentration of RpoS is a decisive parameter for its described function. So far the homologs of the proteolysis targeting factor RssB and the ATP-depending terminal protease complex ClpXP were identified to be involved in V. cholerae RpoS-proteolysis. Further characterization also unravelled, that various stress signals slow down that degradation. But such conditions did not yield in the RpoS accumulation. Based on these differences to the E. coli dynamics of RpoS-degradation additional investigations were performed to gain more insights into the regulatory path of RpoS degradation in V. cholerae. In E. coli the ArcB kinase ist the sensor kinase for regulating the activity of RssB. In this study fexB was identified as arcB homolog in V. cholerae. But by monitoring the RpoS stability in the corresponding knock-out mutant no effect could be observed. Therefore the ArcB-system is not influencing RpoS stability in V. cholerae. Knowing, that RpoS is a major regulator for motility and chemotaxis in V. cholerae, it was investigated next whether other signal-kinases are involved in RpoS proteolysis. Thereby, the known chemotaxis kinases were tested. Knockout mutants of cheAs and subsequent analysis of RpoS half-life revealed, that cheA-1 and cheA-3 did alter RpoS proteolysis to slow down the degradation, whereas cheA-2 mutant did not. Therefore, it can be postulated, that a different mode of RpoS-proteolysis is operating in V. cholerae in which active CheA-1 and CheA-3 may be responsible for RssB phosphorylation, hence leading to RpoS degradation. That kind of interaction may also include the output signalling of the MCP-receptors regulating CheA kinase activity. Since the cheA genes are also under transcriptional control by RpoS a new regulation system can be postulated, where MCP signal output links transcriptional regulation of motility and chemotaxis via RpoS stability in a “positive feedback loop”. Additionally, data are presented, where the ATP depending protease Lon is also involved in RpoS proteolysis in an inverted manner. Lon, which in E. coli is a heat shock induced protease, seems to recognize and degrade substrates in V. cholerae operating in RpoS degradation in the RssB-depending branch. That phenotype was observed as an accelerated RpoS degradation in a lon background. Finally, the complex regulatory pathway of osmo-regulation was characterized. In E. coli RpoS plays a central role. However, in V. cholerae RpoS could not be identified to participate in osmo-regulation, instead a new defined osmostress-sensor (OsmRK) was characterized. In first analysis, it was found that osmRK knockout mutants showed a deregulated ompU expression under hyperosmotic conditions. Considering, that so far only the well known virulence regulator ToxR was identified to act on the ompU promoter, a novel regulatory network was suggested, which regulates at least further 52 genes. In summary, the components of RpoS proteolysis in V. cholerae were unravelled and characterized. Additionally, evidence could be gathered, which indicates a linkage between transcriptional control of motility and chemotaxis genes and the chemotaxis-signalling pathway. So far, such an regulatory pathway has not been described before and would represent a novel branch of signal transduction in bacteria. KW - V. cholerae KW - RpoS KW - Chemotaxis KW - Virulenz KW - V. cholerae KW - RpoS KW - chemotaxis KW - virulence Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-27325 ER - TY - JOUR A1 - Streck, Laura Elisa A1 - Gaal, Chiara A1 - Forster, Johannes A1 - Konrads, Christian A1 - Hertzberg-Boelch, Sebastian Philipp von A1 - Rueckl, Kilian T1 - Defining a synovial fluid white blood cell count threshold to predict periprosthetic infection after shoulder arthroplasty JF - Journal of Clinical Medicine N2 - Background: The diagnosis of periprosthetic shoulder infection (PSI) requires a thorough diagnostic workup. Synovial fluid aspiration has been proven to be a reliable tool in the diagnosis of joint infections of the lower extremity, but shoulder specific data is limited. This study defines a threshold for synovial fluid white blood cell count (WBC) and assesses the reliability of microbiological cultures. Methods: Retrospective study of preoperative and intraoperative fluid aspiration of 31 patients who underwent a revision of a shoulder arthroplasty (15 with PSI defined by IDSA criteria, 16 without infection). The threshold for WBC was calculated by ROC/AUC analysis. Results: WBC was significantly higher in patients with PSI than in other patients. A threshold of 2800 leucocytes/mm\(^3\) showed a sensitivity of 87% and a specificity of 88% (AUROC 0.92). Microbiological cultures showed a sensitivity of 76% and a specificity of 100%. Conclusions: A threshold of 2800 leucocytes/mm\(^3\) in synovial fluid can be recommended to predict PSI. Microbiological culture has an excellent specificity and allows for targeted antibiotic therapy. Joint aspiration presents an important pillar to diagnose PSI. KW - upper extremity KW - joint infection KW - joint aspiration KW - leucocyte count KW - cutibacteria KW - ICM KW - MSIS KW - IDSA KW - WBC Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252275 SN - 2077-0383 VL - 11 IS - 1 ER - TY - JOUR A1 - Surat, Güzin A1 - Vogel, Ulrich A1 - Wiegering, Armin A1 - Germer, Christoph-Thomas A1 - Lock, Johan Friso T1 - Defining the scope of antimicrobial stewardship interventions on the prescription quality of antibiotics for surgical intra-abdominal infections JF - Antibiotics N2 - Background: The aim of this study was to assess the impact of antimicrobial stewardship interventions on surgical antibiotic prescription behavior in the management of non-elective surgical intra-abdominal infections, focusing on postoperative antibiotic use, including the appropriateness of indications. Methods: A single-center quality improvement study with retrospective evaluation of the impact of antimicrobial stewardship measures on optimizing antibacterial use in intra-abdominal infections requiring emergency surgery was performed. The study was conducted in a tertiary hospital in Germany from January 1, 2016, to January 30, 2020, three years after putting a set of antimicrobial stewardship standards into effect. Results: 767 patients were analyzed (n = 495 in 2016 and 2017, the baseline period; n = 272 in 2018, the antimicrobial stewardship period). The total days of therapy per 100 patient days declined from 47.0 to 42.2 days (p = 0.035). The rate of patients receiving postoperative therapy decreased from 56.8% to 45.2% (p = 0.002), comparing both periods. There was a significant decline in the rate of inappropriate indications (17.4% to 8.1 %, p = 0.015) as well as a significant change from broad-spectrum to narrow-spectrum antibiotic use (28.8% to 6.5%, p ≤ 0.001) for postoperative therapy. The significant decline in antibiotic use did not affect either clinical outcomes or the rate of postoperative wound complications. Conclusions: Postoperative antibiotic use for intra-abdominal infections could be significantly reduced by antimicrobial stewardship interventions. The identification of inappropriate indications remains a key target for antimicrobial stewardship programs. KW - antimicrobial stewardship KW - antibiotic prescription behavior KW - surgical intra-abdominal infections KW - post-operative antibiotic treatment Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223034 SN - 2079-6382 VL - 10 IS - 1 ER - TY - JOUR A1 - Harrison, Odile B. A1 - Claus, Heike A1 - Jiang, Ying A1 - Bennett, Julia S. A1 - Bratcher, Holly B. A1 - Jolley, Keith A. A1 - Corton, Craig A1 - Care, Rory A1 - Poolman, Jan T. A1 - Zollinger, Wendell D. A1 - Frasch, Carl E. A1 - Stephens, David S. A1 - Feavers, Ian A1 - Frosch, Matthias A1 - Parkhill, Julian A1 - Vogel, Ulrich A1 - Quail, Michael A. A1 - Bentley, Stephen D. A1 - Maiden, Martin C. J. T1 - Description and Nomenclature of Neisseria meningitidis Capsule Locus JF - Emerging Infectious Diseases N2 - Pathogenic Neisseria meningitidis isolates contain a polysaccharide capsule that is the main virulence determinant for this bacterium. Thirteen capsular polysaccharides have been described, and nuclear magnetic resonance spectroscopy has enabled determination of the structure of capsular polysaccharides responsible for serogroup specificity. Molecular mechanisms involved in N. meningitidis capsule biosynthesis have also been identified, and genes involved in this process and in cell surface translocation are clustered at a single chromosomal locus termed cps. The use of multiple names for some of the genes involved in capsule synthesis, combined with the need for rapid diagnosis of serogroups commonly associated with invasive meningococcal disease, prompted a requirement for a consistent approach to the nomenclature of capsule genes. In this report, a comprehensive description of all N. meningitidis serogroups is provided, along with a proposed nomenclature, which was presented at the 2012 XVIIIth International Pathogenic Neisseria Conference. KW - genetics KW - nuclear magnetic resonance KW - structural determination KW - meningococcal polysaccharides KW - chemical properties KW - serogroup-Y KW - group-B KW - antigen KW - biosynthesis KW - elucidation Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131703 VL - 19 IS - 4 ER - TY - JOUR A1 - Springer, Jan A1 - Walther, Grit A1 - Rickerts, Volker A1 - Hamprecht, Axel A1 - Willinger, Birgit A1 - Teschner, Daniel A1 - Einsele, Hermann A1 - Kurzai, Oliver A1 - Loeffler, Juergen T1 - Detection of Fusarium Species in Clinical Specimens by Probe-Based Real-Time PCR JF - Journal of Fungi N2 - The mold Fusarium is a ubiquitous fungus causing plant, animal and human infections. In humans, Fusarium spp. are the major cause of eye infections in patients wearing contact lenses or after local trauma. Systemic infections by Fusarium spp. mainly occur in immunosuppressed patients and can disseminate throughout the human body. Due to high levels of resistance to antifungals a fast identification of the causative agent is an urgent need. By using a probe-based real-time PCR assay specific for the genus Fusarium we analysed several different clinical specimens detecting Fusarium spp. commonly found in clinical samples in Germany. Also, a large collection of lung fluid samples of haematological patients was analysed (n = 243). In these, two samples (0.8%) were reproducibly positive, but only one could be confirmed by sequencing. For this case of probable invasive fungal disease (IFD) culture was positive for Fusarium species. Here we describe a rapid, probe-based real-time PCR assay to specifically detect DNA from a broad range of Fusarium species and its application to clinically relevant specimens. KW - probe-based real-time PCR KW - Fusarium KW - bronchoalveolar lavage fluid KW - fungal molecular diagnostics Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193111 SN - 2309-608X VL - 5 IS - 4 ER - TY - JOUR A1 - Endres, Leo M. A1 - Jungblut, Marvin A1 - Divyapicigil, Mustafa A1 - Sauer, Markus A1 - Stigloher, Christian A1 - Christodoulides, Myron A1 - Kim, Brandon J. A1 - Schubert-Unkmeir, Alexandra T1 - Development of a multicellular in vitro model of the meningeal blood-CSF barrier to study Neisseria meningitidis infection JF - Fluids and Barriers of the CNS N2 - Background Bacterial meningitis is a life-threatening disease that occurs when pathogens such as Neisseria meningitidis cross the meningeal blood cerebrospinal fluid barrier (mBCSFB) and infect the meninges. Due to the human-specific nature of N. meningitidis, previous research investigating this complex host–pathogen interaction has mostly been done in vitro using immortalized brain endothelial cells (BECs) alone, which often do not retain relevant barrier properties in culture. Here, we developed physiologically relevant mBCSFB models using BECs in co-culture with leptomeningeal cells (LMCs) to examine N. meningitidis interaction. Methods We used BEC-like cells derived from induced pluripotent stem cells (iBECs) or hCMEC/D3 cells in co-culture with LMCs derived from tumor biopsies. We employed TEM and structured illumination microscopy to characterize the models as well as bacterial interaction. We measured TEER and sodium fluorescein (NaF) permeability to determine barrier tightness and integrity. We then analyzed bacterial adherence and penetration of the cell barrier and examined changes in host gene expression of tight junctions as well as chemokines and cytokines in response to infection. Results Both cell types remained distinct in co-culture and iBECs showed characteristic expression of BEC markers including tight junction proteins and endothelial markers. iBEC barrier function as determined by TEER and NaF permeability was improved by LMC co-culture and remained stable for seven days. BEC response to N. meningitidis infection was not affected by LMC co-culture. We detected considerable amounts of BEC-adherent meningococci and a relatively small number of intracellular bacteria. Interestingly, we discovered bacteria traversing the BEC-LMC barrier within the first 24 h post-infection, when barrier integrity was still high, suggesting a transcellular route for N. meningitidis into the CNS. Finally, we observed deterioration of barrier properties including loss of TEER and reduced expression of cell-junction components at late time points of infection. Conclusions Here, we report, for the first time, on co-culture of human iPSC derived BECs or hCMEC/D3 with meningioma derived LMCs and find that LMC co-culture improves barrier properties of iBECs. These novel models allow for a better understanding of N. meningitidis interaction at the mBCSFB in a physiologically relevant setting. KW - brain endothelial cells KW - bacterial meningitis KW - meningeal blood-csf barrier KW - induced pluripotent stem cells KW - neisseria meningitidis KW - leptomeningeal cells Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300208 VL - 19 IS - 1 ER - TY - THES A1 - Endres, Leo Maximilian T1 - Development of multicellular \(in\) \(vitro\) models of the meningeal blood-CSF barrier to study \(Neisseria\) \(meningitidis\) infection T1 - Entwicklung multizellulärer \(in\) \(vitro\) Modelle der meningealen Blut-Liquor Schranke zur Untersuchung der \(Neisseria\) \(meningitidis\) Infektion N2 - Neisseria meningitidis (the meningococcus) is one of the major causes of bacterial meningitis, a life-threatening inflammation of the meninges. Traversal of the meningeal blood-cerebrospinal fluid barrier (mBCSFB), which is composed of highly specialized brain endothelial cells (BECs), and subsequent interaction with leptomeningeal cells (LMCs) are critical for disease progression. Due to the human-exclusive tropism of N. meningitidis, research on this complex host-pathogen interaction is mostly limited to in vitro studies. Previous studies have primarily used peripheral or immortalized BECs alone, which do not retain relevant barrier phenotypes in culture. To study meningococcal interaction with the mBCSFB in a physiologically more accurate context, BEC-LMC co-culture models were developed in this project using BEC-like cells derived from induced pluripotent stem cells (iBECs) or hCMEC/D3 cells in combination with LMCs derived from tumor biopsies. Distinct BEC and LMC layers as well as characteristic expression of cellular markers were observed using transmission electron microscopy (TEM) and immunofluorescence staining. Clear junctional expression of brain endothelial tight and adherens junction proteins was detected in the iBEC layer. LMC co-culture increased iBEC barrier tightness and stability over a period of seven days, as determined by sodium fluorescein (NaF) permeability and transendothelial electrical resistance (TEER). Infection experiments demonstrated comparable meningococcal adhesion and invasion of the BEC layer in all models tested, consistent with previously published data. While only few bacteria crossed the iBEC-LMC barrier initially, transmigration rates increased substantially over 24 hours, despite constant high TEER. After 24 hours of infection, deterioration of the barrier properties was observed including loss of TEER and altered expression of tight and adherens junction components. Reduced mRNA levels of ZO-1, claudin-5, and VE-cadherin were detected in BECs from all models. qPCR and siRNA knockdown data suggested that transcriptional downregulation of these genes was potentially but not solely mediated by Snail1. Immunofluorescence staining showed reduced junctional coverage of occludin, indicating N. meningitidis-induced post-transcriptional modulation of this protein, as previous studies have suggested. Together, these results suggest a potential combination of transcellular and paracellular meningococcal traversal of the mBCSFB, with the more accessible paracellular route becoming available upon barrier disruption after prolonged N. meningitidis infection. Finally, N. meningitidis induced cellular expression of pro-inflammatory cytokines and chemokines such as IL-8 in all mBCSFB models. Overall, the work described in this thesis highlights the usefulness of advanced in vitro models of the mBCSFB that mimic native physiology and exhibit relevant barrier properties to study infection with meningeal pathogens such as N. meningitidis. N2 - Neisseria meningitidis (der Meningokokkus) ist einer der Hauptursachen bakterieller Meningitis, einer lebensbedrohlichen Entzündung der Hirnhäute. Entscheidend für das für das Voranschreiten der Krankheit ist die Fähigkeit des Erregers, die meningeale Blut-Liquor-Schranke (mBCSFB), bestehend aus spezialisierten Hirnendothelzellen (BECs) und leptomeningealen Zellen (LMCs), zu überwinden und in den submeningealen Raum einzudringen. Da es sich bei N. meningitidis um ein rein humanes Pathogen handelt, beschränkt sich die Erforschung dieser speziellen Interaktion primär auf die Verwendung von in vitro Modellen. Bisher wurden hierfür hauptsächlich periphere oder immortalisierte BECs verwendet, welchen jedoch wichtige Barriere-Eigenschaften fehlen. Um die Interaktion von N. meningitidis mit der mBCSFB in einem physiologisch relevanteren Umfeld zu untersuchen, wurden in dieser Arbeit neuartige BEC-LMC Kokulturmodelle entwickelt. Dabei wurden sowohl BEC-ähnliche Zellen, die aus induzierten pluripotenten Stammzellen generiert wurden (iBECs), als auch hCMEC/D3 Zellen verwendet und zusammen mit LMCs aus Tumorbiopsien kultiviert. Mittels Transmissions-Elektronenmikroskopie und Immunfluoreszenzfärbung konnten die unterschiedlichen Zellschichten und deren Expression charakteristischer zellulärer Marker dargestellt werden. Durchgängige Expression von wichtigen Bestandteilen Barriere-formender Zellverbindungen, sogenannter Tight und Adherens Junctions, wurde in der iBEC-Schicht beobachtet. Die Integrität der zellulären Barriere wurde mittels transendothelialer elektrischer Resistenz (TEER) und Permeabilität gegenüber Natrium-Fluorescein (NaF) bestimmt. Erhöhte TEER-Werte und verringerte NaF-Permeabilität, gemessen über einen Zeitraum von sieben Tagen, zeigten eine durch die Kokultur mit LMCs ausgelöste Steigerung der Dichtigkeit und Stabilität der iBEC-Barriere. Infektionsexperimente mit N. meningitidis zeigten in allen Modellen vergleichbare bakterielle Adhäsion und Invasion der BEC-Schicht. Bakterielle Transmigration durch die gesamten Zellbarriere war im iBEC-LMC Modell kurz nach Infektion nur in geringem Maße detektierbar, nahm jedoch innerhalb von 24 Stunden deutlich zu. Interessanterweise wurde bis zu 24 Stunden nach Infektion noch eine hohe Integrität der Barriere gemessen, welche allerdings im weiteren Verlauf verloren ging. Neben signifikantem TEER-Verlust wurde eine verringerte Expression der Tight und Adherens Junction Proteine ZO-1, claudin-5, und VE-cadherin mittels qPCR festgestellt. qPCR und siRNA Knockdown Experimente deuteten darauf hin, dass dies möglicherweise, aber nicht ausschließlich, auf den Transkriptionsfaktor Snail1 zurückzuführen war. Zusätzlich zu den beobachteten Effekten auf die zelluläre Transkription von Tight Junction Genen, zeigten Immunfluoreszenzfärbungen eine verringerte Expression von Occludin an den Zell-Zell-Verbindungen, was auf eine post-translationale Modulation schließen lässt. Zusammen deuten die Ergebnisse dieser Infektionsstudien auf eine mögliche Kombination aus trans- und parazellulärer bakterieller Transmigration der mBCSFB hin. Zuletzt wurden in dieser Arbeit noch die Immunaktivierung von BECs nach N. meningitidis Infektion in den neuen BEC-LMC Kokulturmodellen untersucht. Hierbei wurde eine erhöhte Expression von Zytokinen, insbesondere Interleukin-8, beobachtet. Insgesamt konnten in dieser Arbeit neue, fortschrittlicher in vitro Modelle der mBCSFB entwickelt werden, welche die humane Physiologie besser widerspiegeln und daher für Infektionsstudien mit Meningitis-verursachenden Erregern wie N. meningitidis von besonderem Nutzen sind. KW - Bakterielle Hirnhautentzündung KW - Blut-Liquor-Schranke KW - Induzierte pluripotente Stammzelle KW - Neisseria meningitidis KW - In-vitro-Kultur KW - Brain endothelial cells KW - Leptomeningeal cells KW - Hirnendothelzellen KW - Leptomeningealzellen Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-346216 ER - TY - JOUR A1 - Strobel, Katharina A1 - Sickenberger, Christina A1 - Schoen, Christoph A1 - Kneitz, Hermann A1 - Kolb-Mäurer, Annette A1 - Goebeler, Matthias T1 - Diagnosis and therapy of Mycobacterium marinum: a single-center 21-year retrospective analysis JF - Journal der Deutschen Dermatologischen Gesellschaft N2 - Background and Objectives In Europe, infections with Mycobacterium (M.) marinum are rare. We conducted a retrospective single-center study to assess the clinical spectrum of M. marinum infection and its diagnosis, treatment and outcome under real-world conditions. Patients and Methods Eighteen patients presenting with M. marinum infections between 1998 and 2018 were identified in the data warehouse of the University Hospital Würzburg and considered for detailed analysis. Results Twelve patients reported aquatic exposure. In 16/18 cases the upper extremities were affected. No invasive infections were detected. Mean time to diagnosis was 15 weeks. Histology revealed granulomatous inflammation in 14 patients while mycobacterial cultures were positive for M. marinum in 16 cases. Most patients received antibiotic monotherapy (14/18) while combination therapy was administered in four cases. Treatment (with a median duration of 10 weeks) was successful in 13 patients. Five patients were lost to follow-up. Conclusions Our retrospective analysis of M. marinum infections at a German tertiary referral center revealed a considerable diagnostic delay and the relevance of microbiological culture, PCR and histology for diagnosis. Monotherapy with clarithromycin (rather than doxycycline) appeared as a reasonable treatment option while immunosuppressed or -compromised patients and those with extended disease received combination therapy. KW - Mycobacterium marinum KW - diagnosis KW - therapy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318428 VL - 20 IS - 9 SP - 1211 EP - 1218 ER - TY - JOUR A1 - Rohde, Jörn A1 - Himmel, Wolfgang A1 - Hofinger, Clemens A1 - Lâm, Thiên-Trí A1 - Schrader, Hanna A1 - Wallstabe, Julia A1 - Kurzai, Oliver A1 - Gágyor, Ildikó T1 - Diagnostic accuracy and feasibility of a rapid SARS-CoV-2 antigen test in general practice - a prospective multicenter validation and implementation study JF - BMC Primary Care N2 - Background PCR testing is considered the gold standard for SARS-CoV-2 diagnosis but its results are earliest available hours to days after testing. Rapid antigen tests represent a diagnostic tool enabling testing at the point of care. Rapid antigen tests have mostly been validated by the manufacturer or in controlled laboratory settings only. External validation at the point of care, particularly in general practice where the test is frequently used, is needed. Furthermore, it is unclear how well point of care tests are accepted by the practice staff. Methods In this prospective multicenter validation study in primary care, general practitioners included adult individuals presenting with symptoms suggesting COVID-19. Each patient was tested by the general practitioner, first with a nasopharyngeal swab for the point of care test (Roche SARS-CoV-2 Rapid Antigen Test) and then with a second swab for PCR testing. Using the RT-PCR result as a reference, we calculated specificity, sensitivity, positive predictive value and negative predictive value, with their 95% confidence intervals. General practitioners and medical assistants completed a survey to assess feasibility and usefulness of the point of care tests. Results In 40 practices in Würzburg, Germany, 1518 patients were recruited between 12/2020 and 06/2021. The point of care test achieved a sensitivity of 78.3% and a specificity of 99.5% compared to RT-PCR. With a prevalence of 9.5%, the positive predictive value was 93.9% and the negative predictive value was 97.8%. General practitioners rated the point of care test as a helpful tool to support diagnostics in patients with signs and symptoms suggestive for infection, particularly in situations where decision on further care is needed at short notice. Conclusion The point of care test used in this study showed a sensitivity below the manufacturer’s specification (Sensitivity 96.25%) in the practice but high values for specificity and high positive predictive value and negative predictive value. Although widely accepted in the practice, measures for further patient management require a sensitive interpretation of the point of care test results. KW - COVID-19 testing KW - feasibility study KW - attitude of health personnel KW - sensitivity and specificity KW - general practice Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299659 VL - 23 IS - 1 ER - TY - JOUR A1 - Springer, Jan A1 - Held, Jürgen A1 - Mengoli, Carlo A1 - Schlegel, Paul Gerhardt A1 - Gamon, Florian A1 - Träger, Johannes A1 - Kurzai, Oliver A1 - Einsele, Hermann A1 - Loeffler, Juergen A1 - Eyrich, Matthias T1 - Diagnostic performance of (1→3)-β-D-glucan alone and in combination with aspergillus PCR and galactomannan in serum of pediatric patients after allogeneic hematopoietic stem cell transplantation JF - Journal of Fungi N2 - Data on biomarker-assisted diagnosis of invasive aspergillosis (IA) in pediatric patients is scarce. Therefore, we conducted a cohort study over two years including 404 serum specimens of 26 pediatric patients after allogeneic hematopoietic stem cell transplantation (alloSCT). Sera were tested prospectively twice weekly for Aspergillus-specific DNA, galactomannan (GM), and retrospectively for (1→3)-β-D-glucan (BDG). Three probable IA and two possible invasive fungal disease (IFD) cases were identified using the European Organization for Research and Treatment of Cancer and the Mycoses Study Group (EORTC/MSGERC) 2019 consensus definitions. Sensitivity and specificity for diagnosis of probable IA and possible IFD was 80% (95% confidential interval (CI): 28–99%) and 55% (95% CI: 32–77%) for BDG, 40% (95% CI: 5–85%) and 100% (95% CI: 83–100%) for GM, and 60% (95% CI: 15–95%) and 95% (95% CI: 75–100%) for Aspergillus-specific real-time PCR. However, sensitivities have to be interpreted with great caution due to the limited number of IA cases. Interestingly, the low specificity of BDG was largely caused by false-positive BDG results that clustered around the date of alloSCT. The following strategies were able to increase BDG specificity: two consecutive positive BDG tests for diagnosis (specificity 80% (95% CI: 56–94%)); using an optimized cutoff value of 306 pg/mL (specificity 90% (95% CI: 68–99%)) and testing BDG only after the acute posttransplant phase. In summary, BDG can help to diagnose IA in pediatric alloSCT recipients. However, due to the poor specificity either an increased cutoff value should be utilized or BDG results should be confirmed by an alternative Aspergillus assay. KW - beta-D-glucan KW - galactomannan KW - real-time PCR KW - Aspergillus KW - pediatric Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234179 SN - 2309-608X VL - 7 IS - 3 ER - TY - THES A1 - Stade, Anne-Kathrin T1 - Die Bedeutung der LPS-Sialylierung für die Interaktion von Neisseria meningitidis mit humanen Wirtszellen T1 - The impact of the LOS sialylation for the interaction of Neisseria meningitidis with human host cells N2 - Neisseria meningitidis kann rasch tödlich verlaufende Erkrankungen wie die Meningokokken-Meningitis und –Sepsis hervorrufen. In den Industriestaaten werden diese Infektionen meist durch Meningokokken der Serogruppen B und C hervorgerufen. Während für die Serogruppe C bereits ein suffizienter Polysaccharidimpfstoff existiert, konnte ein solcher für Stämme der Serogruppe B aufgrund der Immuntoleranz gegen deren N-acetylneuraminsäure noch nicht gefunden werden. Eine Lebendvakzine könnte dieses Problem lösen, da hier viele verschiedene Antigene, welche eine Immunantwort im menschlichen Körper induzieren, zur Verfügung stünden. Die Voraussetzung für eine Lebendvakzine ist Attenuierung eines B-Meningokokken-Stammes durch die Deletion verschiedener Gene. In früheren Untersuchungen ergaben sich Hinweise darauf, dass die LOS-Sialylierung einen Virulenzfaktor darstellt. Das lst-Gen codiert für die α-2,3-Sialyltransferase, deren Aufgabe es ist, die Sialinsäurereste an die Lacto-N-Neotetraose des LOS zu binden. In unserer Arbeit konnten wir zeigen, dass eine lst-Deletionsmutante des Serogruppe-B-Stammes MC58 herstellbar ist. Das Wachstumsverhalten der Mutante in PPM+-Medium unterschied sich nicht von dem des Wildtyps. Auch die Resistenz der Bakterien gegenüber humanem Serum (bis 80%) blieb von der Deletion des lst-Gens unbeeinflusst. Bei der Interaktion mit Epithel- und Endothelzellen allerdings zeigte sich bei der Mutante eine erhöhte Invasivität. Da die Invasion durch Oberflächenproteine wie Opa und Opc vermittelt wird, wäre eine mögliche Begründung für diese Veränderung die bessere Zugänglichkeit dieser Proteine durch das Fehlen der LOS-Sialylierung. Meningokokken mit nicht sialyliertem LOS wurden außerdem von dendritischen Zellen signifikant besser phagozytiert als Wildtyp-Bakterien. Besonders deutlich zeigte sich dies bei fehlender Kapsel. Auch hier ist sicherlich die Maskierung von Bindungsstellen durch Sialinsäuregruppen ein Grund für diese Beobachtung. Weiterhin wurde die Interaktion von Meningokokken verschiedener Serogruppen mit dendritischen Zellen unter besonderer Berücksichtigung des Einflusses der Polysaccharidkapsel untersucht. Die Meningokokken der untersuchten Serogruppen A, B und C wurden von dendritischen Zellen gut phagozytiert und abgetötet. Allerdings waren sowohl die Adhärenz als auch die Phagozytose bei Vorhandensein einer Polysaccharidkapsel stark inhibiert. Neisseria meningitidis-Stämme aller drei getesteten Serogruppen induzierten eine starke Ausschüttung der Zytokine TNF-α, IL-6 und IL-8. Als ein Induktor dieser Substanzen erwiesen sich die Lipooligosaccharide der Meningokokken. Allerdings zeigte sich in den Versuchen auch, dass noch weitere Bakterienbestandteile eine Zytokinausschüttung hervorrufen können. Die Sialylierung der Lipooligosaccharide hatte keinen signifikanten Einfluss auf die Menge der produzierten Zytokine. Mit dieser Arbeit konnten wir zeigen, dass dendritische Zellen mit der Ausschüttung von Zytokinen und der Phagozytose von Bakterien eine wichtige Rolle in der Pathogenese von Erkrankungen durch Meningokokken spielen könnten. Auch beim Zusammenspiel mit DC-s wirkt die Kapsel als Schutzfaktor vor dem Angriff des menschlichen Immunsystems. Dieser Schutz kann durch die LOS-Sialylierung zusätzlich gesteigert werden. Die Deletion des lst-Gens könnte also als ein Baustein für die Konstruktion eines attenuierten Lebendvakzine-Stammes fungieren. N2 - Neisseria meningitidis can cause fulminant diseases like meningococcal meningitis and sepsis. In the industrialized countries these infections are usually induced by Neisseria meningitidis serogroup B or C. While for serogroup C an effective polysaccharide vaccine has already been developed, such is not available for serogroup B yet due to the immune tolerance against their N-acetylneuraminic acid. A live vaccine could solve this problem since many different antigens, which induce an immune answer in the human body, would be expressed here. A live vaccine does require the attenuation of a N. meningitidis B strain by the deletion of different genes. In earlier investigations there was evidence, that sialylation of neisserial lipooligosaccharide (LOS) is one of the virulence factors of menigococci. The lst-gene codes for the α-2,3-sialyltransferase that terminally links sialic acid to the lacto-N-neotetraose residue of neisserial LOS. In our work we could show, that the deletion of lst-gene from N. meningitidis B wild type strain MC58 is possible. The replication of the mutant in PPM+ medium did not differ from that of the wild type strain. Even the resistance in 80% human serum remained uninfluenced by the deletion of lst-gene. The interaction with human epithelial and endothelial cells however was changed by the mutation. Our lst-deletion-mutant was obvious more invasive than the wild type strain. Since the invasion is dependent on surface proteins such as Opa and Opc, a possible reason for this change would be the better accessibility of these proteins by the lost of sialic acid on LOS. In addition MC58 lst was significantly better phagocytosed by dendritic cells than MC58 wild type. Also here the masking of neisserial surface molecules is for sure a reason for this observation. Furthermore we investigated the interaction of dendritic cells with meningococci of different serogroups. N. meningitidis of the examined serogroups A, B and C was well phagocytosed and killed by dendritic cells. However both the adherence and phagocytosis were strongly inhibited by presence a polysaccharide capsule. N. meningitidis of all three tested serogroups induced a strong production of the cytokines TNF-α, IL-6 and IL-8. Lipooligosaccharide was proved to be an inductor of these substances. However we’ve learned from the investigation that there must be other bacteria components that can cause cytokine production. The sialylation of LOS did not have significant influence on the quantity of the produced cytokines. With this work we were able to prove that dendritic cells could play an important role in the pathogenesis of meningococcal diseases by phagocytosis and production of cytokines. The neisserial polysaccharide capsule is also in regard to the interaction with dendritic cells the key mechanism to avoid the attack of the human immune system. Additionally this protection can be increased by the sialylation of LOS. Therefore the deletion of lst-gene could be one of the components for the construction of an attenuate live vaccine. KW - Neisseria meningitidis KW - Meningokokken KW - LPS-Sialylierung KW - Sialyltransferase KW - dendritische Zellen KW - Neisseria meningitidis KW - meningococci KW - LOS sialylation KW - sialyltransferase KW - dendritic cell Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-22374 ER - TY - THES A1 - Abele, Marion T1 - Die Bedeutung des Zwei-Partner-Sekretionssystems für die Adhärenz von Meningokokken an Epithelzellen T1 - The role of the two-partner secretion system in adhesion of meningococci to epithelial cells. N2 - Das two-partner secretion-system (TPS-System) ist ein unter Gram-negativen Bakterien weit verbreiteter Weg der Proteinsekretion. Die als TpsA bezeichneten Exoproteine des TPS Systems benötigen ein spezifisches Partnerprotein (genannt TpsB) in Form eines kanalbildenden Transporters. Im sequenzierten Genom des Meningokokkenstammes MC58 finden sich fünf putative tpsA Gene, die als hemagglutinin/hemolysin-related protein (hrps) bezeichnete werden. Neben MC58 finden sich auch in den anderen sequenzierten Meningokokkenstämmen (FAM18, Z2491, alpha14) hrps. Diese weisen N-terminal Homologien zum filamentösen Hämagglutinin (FHA) von B. pertussis auf, das als TpsA-Protein des two-partner-secretion-system (TPS) aus der Zelle transportiert wird. In dieser Arbeit werden die hrps als hrpA Gene bzw. HrpA-Proteine bezeichnet. Alle sequenzierten Meningokokkenstämme verfügen über tpsB homologe Gene (hrpB), die jeweils in enger Nachbarschaft zu den hrpA Genen zu finden sind. Das Vorhandensein von hrpA und hrpB Genen deutet darauf hin, dass auch Meningokokken über ein funktionales TPS-System verfügen. Bei einer Dot-Blot-Analyse von 830 Meningokokkenstämmen aus einer bayerischen Trägerstudie mit Sonden spezifisch für die C-terminalen Bereiche der im Stamm MC58 gefundenen hrpA Gene hybridisierten 80% der ausgewerteten Stämme mit mindestens einer der Sonden. Stämme der hypervirulenten klonalen Komplexen (ST-8, ST-11, ST32, ST-44) zeigten sogar in über 99% eine positive Reaktion. Dagegen wiesen die nicht-hypervirulenten klonalen Komplexe zu 29% im Dot Blot kein hrpA auf, das homolog zu den hrpA Genen von Stamm MC58 ist, wobei es sich hierbei mehrheitlich (82%) um cnl Stämme handelte, so dass sich nur in 10% der untersuchten Kapsel-null-locus-Stämme (cnl) ein zu den hrpA Genen von MC58 homologes Gen nachweisen ließ. Mit der Hypothese, dass auch diese Stämme ein hrpA besitzen, welches sich im C-terimalen Anteil von denen des MC58 unterscheidet wurden in dieser Arbeit Dot Blots durchgeführt, deren Sonde spezifisch für das hrpB NMC0443 war. 97,6% der mit dieser Sonde untersuchten Stämme zeigten die Anwesenheit eines hrpB Homologs. Um die Vermutung zu bestätigen, dass allen hrpB Genen ein zugehöriges hrpA Gen benachbart liegt, wurden repräsentativ PCRs von häufigen klonalen Komplexen durchgeführt. Dabei konnte gezeigt werden, dass ein TPS-System sowohl in den hypervirulenten als auch den nicht-hypervirulenten klonalen Komplexen der Meningokokken vorkommt. Die vielfältigen Funktionen von bereits untersuchten TpsA Proteinen sind zumeist mit der Pathogenität der Bakterien assoziiert. In dieser Arbeit wurde ein möglicher Einfluss der HrpA Proteine auf die Adhäsion der Bakterien an humane Zellen untersucht. Es konnte gezeigt werden, dass sowohl eine kapsellose, als auch eine kapsellose, LPS-trunkierte hrpA Deletionsmutante signifikant schlechter an Epithelzellen adhäriert als die parentalen Vergleichsstämme. Ebenso zeigten die analog durchgeführten Infektionsversuche mit der hrpB Deletionsmutante einen Adhärenzverlust, der jedoch nur für die unbekapselte und LPS trunkierte hrpB Deletionsmutante signifikant war. In dieser Arbeit ist es gelungen das HrpB Protein des Stammes 2120 in E. coli zu exprimieren und aufzureinigen, sodass die Entwicklung eines gegen HrpB gerichteten Antikörpers in Auftrag gegeben werden konnte. Mit Hilfe dieses Antikörpers sollen noch offene Fragen zur Synthese und dem Transport des HrpB Transportproteins beantwortet werden. Außerdem können weitere Untersuchungen zur Lage und Verteilung der HrpBs in der Meningokokkenmembran dazu beitragen, weiteren Aufschluss über die Komplexität von Pathogenität und Virulenz von N. meningitidis zu geben. N2 - The two-partner secretion system (TPS sytem) is a widely distributed pathway for protein secretion in Gram-negative bacteria. The transport of the exoproteins, named TpsA requires a specific channel-forming transporter protein termed TpsB. The sequenced genome of the Neisseria meningitidis strain MC 58 harbors five putative tpsAs, annotated as hemagglutinin/hemolysin-related protein (hrps). In addition, there are hrps present in the sequenced strains FAM18, Z2491 and alpha14. These hrpAs show N-terminal sequence similarities to filamentous hemagglutinin (FHA) of B. pertussis, which represents the TpsA of the Bordetella TPS. According to their homology with FHA, the hrps are referred to as hrpA genes/ HrpA proteins (TpsA homologue), respectively. All sequenced strains of meningococci possess tpsB homologues genes (hrpB), closed to the hrpA genes, suggesting the presence of a functional TPS in N. meningitidis. A panel of 830 N. meningitidis isolated from healthy individuals was analyzed by dot blotting with specific probes for the C-terminal domain of strain MC58 hrpA genes. 80 % of the isolates were found to be positive for at least one of the probes. A positive signal could be demonstrated in over 99 % of the strains belonging to one of the known hypervirulent lineages (ST-8, ST-11, ST32, ST-44). Interestingly, the presence of a hrpA gene homologous to one of the MC58 hrpA genes could not be detected in 29 % of the non-hypervirulent lineages. Among those strains that did not hybridize with the probes, 82 % belonged to the clonal complex harboring the capsule null locus (cnl). We hypothesized that strains which were negative with the MC58 hrpA probes harbor undetected hrpA genes with C-terminal nucleotide sequences different from those present in strain MC58. Therefore, additional dot blots were performed with a probe specific for the highly conserved meningococcal hrpB gene NMC0443. Almost all strains (97,6%) hybridized with the probe specific for the hrpB gene. As genes for cognate HrpA protein and transporter protein are closely associated in known TPS systems, this hypothesis was tested by PCR of a selection of strains representing common clonal complexes. We showed that the TPS system is ubiquitously present in meningococci both in hypervirulent and non-hypervirulent lineages. Several TpsA proteins have been shown to contribute to virulence of bacteria. In this study we investigated the effect of HrpA proteins to adhesion of bacteria at epithelial cells. A hrpA deletion mutant displayed significantly reduced adherence to epithelial cells. This effect was observed in an unencapsulated background as well as unencapsulated background with truncated LPS. Similary designed studies with a hrpB deletion mutant resulted in reduced adherence, however only in the unencapsulated and LPS truncated background. In this study the HrpB protein was expressed and purified in E. coli and used for generation of an antiserum. This antiserum is available for further investigations concerning synthesis, transport, position and distribution of HrpB. KW - Würzburg / Institut für Hygiene und Mikrobiologie KW - Medizinische Mikrobiologie KW - Meningokokken KW - Zwei-Partner-Sekretionssystem KW - Adärenz KW - Epithelzellen KW - meningococci KW - two-partner secretion system KW - adhesion KW - epithelial cells Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45369 ER - TY - THES A1 - Schäfer, Sabine T1 - Die funktionelle Relevanz humoraler und zellulärer Immunreaktionen gegen Campylobacter jejuni in der Pathogenese von Immunneuropathien T1 - The functional relevance of humoral and cellulare immune responses to Campylobacter jejuni in the pathogenesis of acute neuropathies. N2 - Verschiedene mögliche Pathomechanismen einer Campylobacter jejuni-spezifischen Immunantwort bei der Entstehung akuter Immunneuropathien wurden untersucht. Neben anderen wurden für die Untersuchungen auch C. jejuni-Stämme eingesetzt, welche von Guillain-Barré- (GBS) und Miller-Fisher-syndrome (MFS) Patienten isoliert worden waren. Es wurden Ultraschall-Gesamt-Homogenate der C. jejuni Stämme sowie von Salmonella typhimurium als Kontrollbakterium hergestellt. Anschließend wurden verschiedene Proteinfraktionen isoliert und die Lipopolysaccharide (LPS) der Bakterien isoliert. Durch Immunisierung von Ratten mit diesen C. jejuni-Präparationen konnten keine Krankheitszeichen der experimentellen autoimmunen Neuritis (EAN) ausgelöst werden. Trotz Produktion hoher Titer C. jejuni-spezifischer Antikörper verlief in diesen Tieren eine anschließend durch P2-spezifische T-Lymphozyten induzierte adoptiv transferierte EAN (AT-EAN) nicht schwerer als in mit komplettem Freund´schen Adjuvans (CFA) kontrollimmunisierten Ratten. Nach Immunisierung mit C. jejuni-Protein wurden C. jejuni-spezifische T-Zellen von Lewis-Ratten gewonnen, die mit allen getesteten C. jejuni-Stämmen als Antigen reagieren, jedoch zeigten C. jejuni-spezifische Ratten-T-Zellen in vitro keine Kreuzreaktivität mit PNS-Antigenen und induzierten in vivo keine Neuritis. Im Modell der EAN läßt sich durch Füttern des Antigens eine natürliche orale Toleranz induzieren, welche die Tiere gegen eine aktiv induzierte EAN resistent macht. Die immunologische Auswirkung der enteralen Gabe von C. jejuni-LPS auf die natürliche Immuntoleranz wurde untersucht. Dabei konnte bei diskrepanten Ergebnissen keine pathogene Bedeutung von enteralen C. jejuni-Antigenen in der Ratte festgestellt werden. Zur Generation und Untersuchung C. jejuni-spezifischer monoklonaler Antikörper wurden Balb/c-Mäuse mit C. jejuni-LPS-Präparationen in CFA immunisiert und die Milzzellen dieser Tiere mit Maus-Myelomzellen fusioniert. Es konnte eine Vielzahl von monoklonalen Antikörpern etabliert werden. Selektive Spezifitäten der monoklonalen Antikörper für C. jejuni-LPS oder -protein wurden detektiert, die meisten der monoklonalen Antikörper als IgM, einige als IgG charakterisiert. Die Antikörper reagieren mit allen getesteten C. jejuni-Stämmen sowohl im ELISA als auch im Western Blot kreuz. Eine Reaktivität der Antikörper mit verschiedenen Gangliosiden konnte nicht nachgewiesen werden. Zur Untersuchung eines elektrophysiologisch fassbaren blockierenden Effektes von C. jejuni-spezifischen Antikörpern wurden Makro-patch-clamp-Untersuchungen am Mäusezwerchfell mit dialysierten Seren von C. jejuni-immunisierten Ratten durchgeführt. Einige der C. jejuni-Antiseren blockierten die präsynaptische Quantenfreisetzung partiell. Dieser Effekt war C. jejuni-spezifisch und durch Salmonella-Antiserum oder Kontrollseren CFA-immunisierter Tiere nicht induzierbar. Ein von uns generierter monoklonaler IgG-Antikörper gegen C. jejuni-LPS wurde ebenfalls in Makro-patch-clamp-Untersuchungen getestet und blockierte die Quantenfreisetzung. Weiterhin wurden humane T-Zellen gegen C. jejuni HB 93-13 generiert. Es konnte erstmals gezeigt werden, daß diese Zellen mit anderen C. jejuni-Stämmen, jedoch nicht mit Salmonellen, kreuzreagieren und ausschließlich Proteine jedoch nicht LPS erkennen. Die generierten Zellen sind alle HLA-DR restringiert und der Phänotyp wurde als CD 4+/CD 8-, /-TZR+ identifiziert. Einige der C. jejuni-spezifischen T-Zell-Linien zeigten eine starke oder partielle Kreuzreaktivität mit humanem rekombinantem P2-Protein des PNS und mit einzelnen P2-Peptiden. Dieser Befund belegt erstmals, dass durch Konfrontation mit C. jejuni eine zelluläre Immunantwort angestoßen werden kann, die in autoimmuner Weise mit Myelinprotein des PNS kreuzreagiert. N2 - The present study evaluates the putative pathogenic role of a Campylobacter jejuni directed immune response in the pathogenesis of acute neuropathies. Among other C. jejuni strains, strains isolated from Guillain-Barré- (GBS) and Miller-Fisher syndrome (MFS) patients were used for this investigation. By sonication, total homogenate of different C. jejuni strains and Salmonella typhimurium, which served as a control, were prepared. Additionally, different protein fractions and bacterial lipopolysaccharides (LPS) were isolated. Immunization of rats with C. jejuni preparations did not lead to clinical manifestation of active experimental autoimmune neuritis (EAN). Furthermore, the severity of adoptive transfer-EAN (AT-EAN), induced by adoptively transferred P2-specific T cells was not altered in rats that had been previously immunized with C. jejuni for production of high anti-C. jejuni antibody titers. C. jejuni-specific T cell lines were generated from Lewis rats immunized with C. jejuni proteins. These T cells proliferated in an antigen-specific manner in the presence of extracts from different C. jejuni strains. C. jejuni-specific rat T cells did not show any cross-reactive proliferation to peripheral nervous system (PNS) antigens. Furthermore, it was not possibe to induce neuritis by adoptive transfer of C. jejuni-specific T cells in vivo. Oral application of myelin antigens induces oral tolerance which renders rats resistant to actively induced EAN. This observation lead to analyse the immunological consequences of oral administration of C. jejuni LPS with respect to the induction of tolerance. C. jejuni/myelin-fed rats developed accelerated clinical sings of EAN compared to control animals. Thus, oral administration of C. jejuni HB 93-13 LPS inhibited the induction of myelin-specific oral tolerance. In order to investigate the humoral immune response, monoclonal C. jejuni-specific antibodies were isolated by immunization of Balb/c mice with C. jejuni LPS preparations emulsified in complete Freund´s adjuvant (CFA). Splenocytes from primed animals were fused with myeloma cells. A number of monoclonal antibodies were characterized. These monoclonal antibodies were either specific for C. jejuni LPS or C. jejuni proteins. These immunoglobulins were characterized to be predominantly IgM, but also IgG antibodies could be found. ELISA and western blot analysis verified cross-reactivity of antibodies with different C. jejuni strains. However, the antibodies were not able to recognize gangliosides. Electrophysiological investigations were used to determine a possible blocking effect of C. jejuni-specific antibodies at the neuromusculare endplate. Alteration of neuromuscular transmission at the diaphragm of mice after appling dialysed sera of C. jejuni immunized rat, were investigated using patch-clamp. Several C. jejuni antisera were able to partially block the pre-synaptic quantal release. This effect was C. jejuni-specific and was not inducible by Salmonella typhimurium antisera or control sera, obtained from CFA immunized animals. Additionally, one of the generated monoclonal C. jejuni LPS specific IgG antibodies was able to block the quantal release. Finally, we were able to generate human T cells reacting specifically with C. jejuni HB 93-13. For the first time it could be shown, that these cells respond to homogenates of other C. jejuni strains but not to Salmonella typhimurium homogenate. Specifically C. jejuni proteins but not C. jejuni LPS were recognized by the human T cell lines. The generated T cells were all HLA-DR restricted and identified to be CD4+/CD8-, /-TCR+. A few of the C. jejuni-specific T cell lines demonstrated a strong cross-reactivity to a PNS-component, the recombinant human P2-protein and single P2-peptides. This observation shows that C. jejuni induces a variety of antigen-specific and non-specific immune responses which are able to facilitate or even trigger autoimmunity against the PNS as occuring in GBS or the MFS. KW - Campylobacter jejuni KW - Immunreaktion KW - Guillain-Barr'e-Syndrom KW - Campylobacter jejuni KW - Guillain-Barré Syndrom KW - Campylobacter jejuni KW - Guillain-Barré syndrome Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-5531 ER - TY - THES A1 - Eibicht, Sebastian Johannes T1 - Die Kontamination von Flächen mit MRSA in Krankentransport- und Rettungswagen bei Kurzzeittransporten von MRSA-Patienten T1 - Meticillin-resistant Staphylococcus aureus (MRSA) contamination of ambulance cars after short term transport of MRSA-colonised patients N2 - Die Innenausbauflächen von Krankentransport- bzw. Rettungswagen unterliegen dem Risiko einer Verunreinigung durch Methicillin-resistenten S. aureus (MRSA). In der vorliegenden Arbeit wurden Krankentransport- bzw. Rettungswagen unmittelbar nach dem Transport von MRSA-kolonisierten oder -infizierten Patienten auf MRSA untersucht. Zu diesem Zweck wurden an 2 Stellen der Trage und an 3 Stellen der Innenausbauflächen Proben entnommen. 89 von 100 untersuchten Transporten, welche das Einschlusskriterium einer Transportzeit von weniger als 20 Minuten erfüllten, wurden weitergehend analysiert. 8 der untersuchten Kranken- bzw. Rettungswagen (7,1%) wiesen eine Kontamination auf (90% Konfidenzintervall: 4-14 %), wobei die Transportzeit keinen Einfluss auf die Kontamination hatte. MRSA wurde nur an der Trage nachgewiesen und zwar ausschließlich am Kopfteil der Trage und an den Tragegriffen. Die beprobten Stellen der Innenausbauflächen waren nicht kontaminiert. Bei Kurzzeittransporten von MRSA-positiven Patienten sollte daher der Fokus der Desinfektion auf die Oberflächen in unmittelbarer Patientennähe gelegt werden. Eine weitere Untersuchung von 60 Transporten MRSA-negativer Patienten blieb ohne MRSA-Befund. In 12 dieser Krankentransportwagen wurde jedoch Methicillin-sensibler S. aureus nachgewiesen, der sich ebenfalls vorwiegend an Kopfteil und Handgriffen der Trage fand. Auch dieses Ergebnis unterstreicht die Bedeutung der Desinfektion patientennaher Flächen unabhängig vom MRSA-Status der transportierten Patienten. N2 - Patients carrying MRSA provide a risk of surface contamination with MRSA in ambulance cars. This study analysed whether surfaces of ambulance cars, in which MRSA-colonised or -infected patients were transported, were contaminated with MRSA and where the contamination occurred. 89 transportation events lasting less than 20 minutes were included in the analysis. 8 ambulance cars (7,1%) were found to be contaminated with MRSA following transport (90% confidence interval: 4-14%). The transport time was not relevant for the contamination rate. MRSA was exclusively found on the stretcher, i.e. the headrest and the handles. This finding sug¬gests that disinfection measures after transport should be focused on the patients' contact surfaces. Consecutive investigation included 60 transport events in the absence of MRSA-notification and demonstrated that MSSA, but not MRSA, could be detected in 12 cars, again mostly at handles and headrests. This study shows the importance of disinfection of surfaces in the vicinity of patients transported in an ambulance irrespective of the patients' MRSA-status KW - MRSA KW - Methicillin-resistenter S. aureus KW - Krankentransportwagen KW - ambulance car KW - MRSA-Kontamination von Oberflächen KW - Cabin surfaces contaminated with MRSA KW - MRSA-kolonisierten Patienten KW - MRSA-colonised patients KW - Kurzzeittransporten KW - Shorttime transport KW - Rettungsdienst KW - rescue service Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-207130 ER - TY - THES A1 - Kraft, Christian T1 - Die Rolle von Mutation und Rekombination in der Mikroevolution von Helicobacter pylori T1 - The role of mutation and recombination in the microevolution of Helicobacter pylori N2 - Helicobacter pylori ist ein pathogenes Bakterium, das verantwortlich gemacht wird für verschiedene Erkrankungen des Magens und Duodenums, wie beispielsweise chronische Gastritis, peptische Ulzera und maligne Lymphome. Das Bakterium zeichnet sich durch eine hohe Rekombinationsrate aus und besitzt ein hohes Maß an genetischer Allelvielfalt. Im ersten Teil dieser Arbeit wurde die Rekombinationsrate und die Länge der rekombinerten DNA-Importe anhand von sequentiellen Isolaten, die zu definierten Zeitpunkten aus dem selben Patienten isoliert wurden, untersucht. Es wurden zehn Gene, darunter sieben 'housekeeping' Gene und drei virulenzassoziierte Gene, amplifiziert und sequenziert. Die Ergebnisse zeigten eine bis dahin noch nicht für Bakterien beschriebene Fragmentlänge der DNA-Importe von durchschnittlich lediglich 417 Basenpaaren. Die Rekombinationsrate war außergewöhnlich hoch. DNA-Microarray-Analysen konnten zeigen, dass es trotz dieser hohen Rekombinationsrate nur wenige Veränderungen in der genomischen Genausstattung gab. Jedoch hing das Auftreten von Rekombinationsereignissen direkt mit Veränderungen der Genausstattung zusammen. Im zweiten Teil der Arbeit wurde ein neues in vitro-Transformationsmodell entwickelt, das die in vivo ermittelten Resultate nachvollziehen sollte. Das Modell konnte sowohl die in vivo gefundene Rekombinationsrate als auch den Import von kurzen DNA-Fragmenten bestätigen, die zu einem Allelmosaik zwischen DNA-Rezipient und Donor führten. Auffällig war eine stark verminderte Transformierbarkeit mit Donor-DNA aus asiatischen H. pylori-Stämmen. Um eine mögliche Beteiligung des Nukleotid-Excisions-Reparatur (NER) Mechanismus an der Rekombination zu ermitteln, wurden zwei Gene des Mechanismus ausgeschaltet. Die Ergebnisse der NER--Mutanten (uvrA-, uvrD-) zeigten eine starke Verminderung der Transformierbarkeit. Diese Verminderung hatte jedoch keinen Einfluss auf die Länge der rekombinierten DNA-Importe. Das Ausschalten des uvrA-Gens führte zudem zu einer erhöhten Sensibilität gegenüber UV-Licht. Der NER-Mechanismus ist bei H. pylori in einer noch nicht aufgeklärten Weise an der Rekombination beteiligt. In einem Rhesusaffen-Tiermodell wurde die initiale Besiedlung mit H. pylori untersucht. Die Tiere stellen einen natürlichen Wirt dar und zeigen ähnliche Krankheitssymptome wie menschliche Patienten. Die Rhesusaffen wurden experimentell mit zwei klinischen H. pylori-Isolaten infiziert. Die Reisolation zu bestimmten Zeitpunkten zeigte, dass sich nur einer der beiden Stämme im Affenmagen etablieren konnte und der zweite Stamm verdrängt worden war. In einem zweiten Versuchsansatz wurden die persistent infizierten Affen mit vier weiteren H. pylori-Stämmen infiziert, um eine transiente Koinfektion zu simulieren. Diese Stämme verdrängten jedoch den bereits etablierten Stamm, und es konnte keine in vivo-Rekombination festgestellt werden. Dennoch ist dieses Modell das Erste, in dem eine persistierende experimentelle H. pylori-Infektion in Rhesusaffen über einen Zeitraum von mehr als vier Jahren nachgewiesen werden konnte. Die Ergebnisse liefern wichtige Hinweise auf den beim Menschen meist unentdeckten Anfang der H. pylori-Infektion. Die Untersuchungen an weiteren Spezies des Genus Helicobacter zeigten, dass die beschriebene Spezies Heelicobacter nemestrinae keine eigene Spezies darstellt, sondern der Spezies H. pylori zugeordnet werden konnte. Den damit nächsten 'Verwandten' stellt die Spezies H. acinonychis dar, deren Stämme sich untereinander wesentlich weniger stark unterscheiden als H. pylori-Stämme. Die Ergebnisse dieser Arbeit liefern wichtige Daten zum Verständnis der Evolution und Mikroevolution innerhalb eines Wirtes von H. pylori, die zu besseren Strategien in der Bekämpfung dieses pathogenen Bakteriums führen können. N2 - The human pathogen Helicobacter pylori colonizes the gastrointestinal tract and causes a long-term infection leading to several diseases such as gastritis, peptic ulcers and cancer. H. pylori is the most genetically diverse bacterial species known. Population genetic analysis has shown that the diversity is largely due to recombination between different H. pylori strains during mixed infection. To analyse the recombination rate in vivo, sequential isolates, taken from the same patient at different timepoints, were used. Fragments of seven housekeeping genes, the two flagellin genes and the vacuolating cytotoxin gene vacA, were sequenced and pairwisely compared to detect genetic changes that had occurred during chronic colonization. The recombination rate was unexpectedly high and the size of the imported DNA-fragments had an average of only 417 basepairs. DNA-imports of this extraordinarily short length were never found before in other bacterial species so far. A Microarray analysis showed a high stability of the genetic content in the paired isolates. The very few differences in this genetic content were mainly driven by recombination events. A new developed in vitro transformation model was able to measure the recombination frequency and the length of the imported DNA. The model confirmed the unusually high recombination frequency and the very short imported DNA fragments found in vivo in the sequential isolates. Interestingly, by using Asian strains as DNA donor, the recombination frequency was much lower compared to European and African strains. To answer the question whether the nucleotide-excision-repair (NER) mechanism was involved in the recombination process, knock out mutants of two key genes of the mechanism were used (uvrA-, uvrD-). The NER mutants showed a notable decrease in their transformation ability, but the length of the imported fragments was not affected. The NER mechanism seems to be involved in the recombination process, but it is still unknown in how far and in which way. A rhesus monkey model was developed to establish an experimentally persistent H. pylori infection and to investigate the initial infection steps. Macaques are natural hosts of H. pylori and develop similar disease. Two clinical isolates were chosen for infection, but only one strain survived in the stomach of the macaques. The second strain was outcompeted by the first one. In a second trial the macaques were infected with four new strains of H. pylori to simulate a transient co-colonisation. Only two of the new strains survived and the formerly established strain was outcompeted by the two new strains. No recombination events could be detected. Nevertheless, this is the first time that rhesus monkeys were experimentally persistently infected for more than four years with H. pylori. In this model the first steps of an new H. pylori infection can be investigated, which is not possible in humans. Investigations of other members of the genus Helicobacter showed, that the species Helicobacter nemestrinae was not an independent species, but represented a strain of H. pylori. The closest related species then was represented by Helicobacter acinonychis. Genetic analyses revealed a much more clonal genome between different H. acinonychis strains compared to H. pylori. KW - Helicobacter pylori KW - Evolution KW - Molekulargenetik KW - Helicobacter KW - Evolution KW - Helicobacter KW - evolution Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-9757 ER - TY - JOUR A1 - Schubert-Unkmeir, Alexandra A1 - Schneider-Schaulies, Sibylle A1 - Gulbins, Erich A1 - Hebling, Sabrina A1 - Simonis, Alexander T1 - Differential Activation of Acid Sphingomyelinase and Ceramide Release Determines Invasiveness of Neisseria meningitidis into Brain Endothelial Cells N2 - The interaction with brain endothelial cells is central to the pathogenicity of Neisseria meningitidis infections. Here, we show that N. meningitidis causes transient activation of acid sphingomyelinase (ASM) followed by ceramide release in brain endothelial cells. In response to N. meningitidis infection, ASM and ceramide are displayed at the outer leaflet of the cell membrane and condense into large membrane platforms which also concentrate the ErbB2 receptor. The outer membrane protein Opc and phosphatidylcholine-specific phospholipase C that is activated upon binding of the pathogen to heparan sulfate proteoglycans, are required for N. meningitidis-mediated ASM activation. Pharmacologic or genetic ablation of ASM abrogated meningococcal internalization without affecting bacterial adherence. In accordance, the restricted invasiveness of a defined set of pathogenic isolates of the ST-11/ST-8 clonal complex into brain endothelial cells directly correlated with their restricted ability to induce ASM and ceramide release. In conclusion, ASM activation and ceramide release are essential for internalization of Opc-expressing meningococci into brain endothelial cells, and this segregates with invasiveness of N. meningitidis strains. Author Summary Neisseria meningitidis, an obligate human pathogen, is a causative agent of septicemia and meningitis worldwide. Meningococcal infection manifests in a variety of forms, including meningitis, meningococcemia with meningitis or meningococcemia without obvious meningitis. The interaction of N. meningitidis with human cells lining the blood vessels of the blood-cerebrospinal fluid barrier is a prerequisite for the development of meningitis. As a major pathogenicity factor, the meningococcal outer membrane protein Opc enhances bacterial entry into brain endothelial cells, however, mechanisms underlying trapping of receptors and signaling molecules following this interaction remained elusive. We now show that Opc-expressing meningococci activate acid sphingomyelinase (ASM) in brain endothelial cells, which hydrolyses sphingomyelin to cause ceramide release and formation of extended ceramide-enriched membrane platforms wherein ErbB2, an important receptor involved in bacterial uptake, clusters. Mechanistically, ASM activation relied on binding of N. meningitidis to its attachment receptor, HSPG, followed by activation of PC-PLC. Meningococcal isolates of the ST-11 clonal complex, which are reported to be more likely to cause severe sepsis, but rarely meningitis, barely invaded brain endothelial cells and revealed a highly restricted ability to induce ASM and ceramide release. Thus, our results unravel a differential activation of the ASM/ceramide system by the species N. meningitidis determining its invasiveness into brain endothelial cells. KW - small interfering RNAs KW - Neisseria meningitidis KW - bacterial pathogens KW - endothelial cells KW - meningococcal disease KW - flow cytometry KW - cell staining KW - Escherichia coli infections Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113031 ER - TY - JOUR A1 - Weiß, Martin A1 - Gründahl, Marthe A1 - Deckert, Jürgen A1 - Eichner, Felizitas A. A1 - Kohls, Mirjam A1 - Störk, Stefan A1 - Heuschmann, Peter U. A1 - Hein, Grit T1 - Differential network interactions between psychosocial factors, mental health, and health-related quality of life in women and men JF - Scientific Reports N2 - Psychosocial factors affect mental health and health-related quality of life (HRQL) in a complex manner, yet gender differences in these interactions remain poorly understood. We investigated whether psychosocial factors such as social support and personal and work-related concerns impact mental health and HRQL differentially in women and men during the first year of the COVID-19 pandemic. Between June and October 2020, the first part of a COVID-19-specific program was conducted within the “Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression (STAAB)” cohort study, a representative age- and gender-stratified sample of the general population of Würzburg, Germany. Using psychometric networks, we first established the complex relations between personal social support, personal and work-related concerns, and their interactions with anxiety, depression, and HRQL. Second, we tested for gender differences by comparing expected influence, edge weight differences, and stability of the networks. The network comparison revealed a significant difference in the overall network structure. The male (N = 1370) but not the female network (N = 1520) showed a positive link between work-related concern and anxiety. In both networks, anxiety was the most central variable. These findings provide further evidence that the complex interplay of psychosocial factors with mental health and HRQL decisively depends on gender. Our results are relevant for the development of gender-specific interventions to increase resilience in times of pandemic crisis. KW - anxiety KW - depression KW - human behaviour KW - quality of life Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357858 VL - 13 ER - TY - JOUR A1 - Sturm, Laura A1 - Geißel, Bernadette A1 - Martin, Ronny A1 - Wagener, Johannes T1 - Differentially Regulated Transcription Factors and ABC Transporters in a Mitochondrial Dynamics Mutant Can Alter Azole Susceptibility of Aspergillus fumigatus JF - Frontiers in Microbiology N2 - Azole resistance of the fungal pathogen Aspergillus fumigatus is an emerging problem. To identify novel mechanisms that could mediate azole resistance in A. fumigatus, we analyzed the transcriptome of a mitochondrial fission/fusion mutant that exhibits increased azole tolerance. Approximately 12% of the annotated genes are differentially regulated in this strain. This comprises upregulation of Cyp51A, the azole target structure, upregulation of ATP-binding cassette (ABC) superfamily and major facilitator superfamily (MFS) transporters and differential regulation of transcription factors. To study their impact on azole tolerance, conditional mutants were constructed of seven ABC transporters and 17 transcription factors. Under repressed conditions, growth rates and azole susceptibility of the mutants were similar to wild type. Under induced conditions, several transcription factor mutants showed growth phenotypes. In addition, four ABC transporter mutants and seven transcription factor mutants exhibited altered azole susceptibility. However, deletion of individual identified ABC transporters and transcription factors did not affect the increased azole tolerance of the fission/fusion mutant. Our results revealed the ability of multiple ABC transporters and transcription factors to modulate the azole susceptibility of A. fumigatus and support a model where mitochondrial dysfunctions trigger a drug resistance network that mediates azole tolerance of this mold. KW - mitochondrial dynamics KW - azole resistance KW - efflux pumps KW - transcription factors Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204874 SN - 1664-302X VL - 11 ER - TY - JOUR A1 - Muenstermann, Marcel A1 - Strobel, Lea A1 - Klos, Andreas A1 - Wetsel, Rick A. A1 - Woodruff, Trent M. A1 - Köhl, Jörg A1 - Johswich, Kay O. T1 - Distinct roles of the anaphylatoxin receptors C3aR, C5aR1 and C5aR2 in experimental meningococcal infections JF - Virulence N2 - The complement system is pivotal in the defense against invasive disease caused by Neisseria meningitidis (Nme, meningococcus), particularly via the membrane attack complex. Complement activation liberates the anaphylatoxins C3a and C5a, which activate three distinct G-protein coupled receptors, C3aR, C5aR1 and C5aR2 (anaphylatoxin receptors, ATRs). We recently discovered that C5aR1 exacerbates the course of the disease, revealing a downside of complement in Nme sepsis. Here, we compared the roles of all three ATRs during mouse nasal colonization, intraperitoneal infection and human whole blood infection with Nme. Deficiency of complement or ATRs did not alter nasal colonization, but significantly affected invasive disease: Compared to WT mice, the disease was aggravated in C3ar\(^{-/-}\) mice, whereas C5ar1\(^{-/-}\) and C5ar2\(^{-/-}\) mice showed increased resistance to meningococcal sepsis. Surprisingly, deletion of either of the ATRs resulted in lower cytokine/chemokine responses, irrespective of the different susceptibilities of the mice. This was similar in ex vivo human whole blood infection using ATR inhibitors. Neutrophil responses to Nme were reduced in C5ar1\(^{-/-}\) mouse blood. Upon stimulation with C5a plus Nme, mouse macrophages displayed reduced phosphorylation of ERK1/2, when C5aR1 or C5aR2 were ablated or inhibited, suggesting that both C5a-receptors prime an initial macrophage response to Nme. Finally, in vivo blockade of C5aR1 alone (PMX205) or along with C5aR2 (A8\(^{Δ71−73}\)) resulted in ameliorated disease, whereas neither antagonizing C3aR (SB290157) nor its activation with a “super-agonist” peptide (WWGKKYRASKLGLAR) demonstrated a benefit. Thus, C5aR1 and C5aR2 augment disease pathology and are interesting targets for treatment, whereas C3aR is protective in experimental meningococcal sepsis. KW - inflammation KW - C3a KW - C5a KW - C3aR KW - C5aR1 KW - C5aR2 KW - meningococcal disease KW - sepsis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200496 VL - 10 IS - 1 ER - TY - THES A1 - Aldejohann, Alexander Maximilian T1 - Echinocandin-Resistenzen in \(Candida\) \(glabrata\) T1 - Echinocandin resistance in \(Candida\) \(glabrata\) N2 - Candida glabrata ist die zweithäufigste Ursache von Candidämien und invasiven Hefepilzinfektionen in Europa. Im Gegensatz zu C. albicans zeigt C. glabrata eine reduzierte Empfindlichkeit gegen bestimmte Antimykotika und kann unter Therapie rasch Resistenzen entwickeln. Diese Arbeit umfasst eine systematische geno- und phänotypische Resistenzanalyse einer der größten europäischen - durch das NRZMyk in 5 Jahren zusammengetragenen - C. glabrata Stammsammlungen bestehend aus 176 klinisch relevanter Isolate. 84 der Stämme wurden anhand Referenztestung nach EUCAST zunächst als Anidulafungin (AND) resistent eingestuft. 71 wiesen konkordante Mutationen in den für die Glucan-Synthetase kodierenden FKS-Genen auf (13 % in FKS1, 87 % in FKS2). Vor allem die Position Ser-663 (FKS2-HS1) imponierte mit signifikant erhöhten AND MHK-Werten. 11 FKS-Wildtyp-Isolate, die ursprünglich als AND resistent klassifiziert wurden, wiesen in multiplen Nachtestungen um den Breakpoint undulierende AND MHK-Werte auf. 2 FKS-Wildtyp Isolate zeigten durchgängig hohe AND MHK-Werte und mussten daher - trotz fehlender Zielgenmutationen - als resistent eingestuft werden. Diese extremen Phänotypen wurden durch einen verblindeten nationalen Ringversuch bestätigt. Über ein Drittel der Isolate war multiresistent. Stämme aus Blutstrominfektionen und Ser-663 Mutation waren mit einer erhöhten Mortalität assoziiert. Ein weiteres Kernelement war die Detektion von Azol-resistenten C. glabrata petite-Phänotypen in der Routinediagnostik. Hier wurden innerhalb von 8 Monaten 20 relevante Isolate identifiziert. Die Ergebnisse belegen das regelmäßige Auftreten single- / multidrug-resistenter C. glabrata Isolate in Deutschland. Phänotypische Resistenztestungen können zu Fehlklassifizierung von sensiblen Isolaten führen. FKS-Genotypisierungen hingegen sind ein nützliches Tool zur Identifizierung relevanter Resistenzen. In seltenen Fällen scheint jedoch eine Echinocandin-Resistenz ohne genotypisches Korrelat möglich zu sein. N2 - Candida glabrata is the second most common cause of candidaemia and invasive yeast infections in Europe. In contrast to C. albicans, C. glabrata shows reduced susceptibility to certain antifungal agents and can rapidly acquire resistance under therapy. This work comprises a systematic geno- and phenotypic resistance analysis of one of the largest European C. glabrata strain collections - compiled by NRZMyk in 5 years - consisting of 176 clinically relevant isolates. 84 of the strains were initially classified as anidulafungin (AND) resistant by reference testing according to EUCAST. 71 showed concordant mutations in FKS genes encrypting the glucan synthetase (13 % in FKS1, 87 % in FKS2). In particular, the position Ser-663 (FKS2-HS1) impressed with significantly increased AND MIC-values. 11 FKS wild-type isolates, originally classified as AND resistant, showed fluctuating AND MIC-values near the clinical breakpoint after retests with multiple assays. Two FKS wild-type isolates showed consistently high AND MIC values and therefore had to be classified as resistant - despite the absence of target gene mutations. These extreme phenotypes were confirmed in a blinded national ring trial. More than one third of echinocandin-resistant isolates showed concordant fluconazole resistance. Strains from bloodstream infections and Ser-663 mutation were associated with high mortality. Another core element was the detection of azole-resistant C. glabrata petite phenotypes in routine diagnostics. Here, 20 relevant isolates were identified within 8 months, which could be assigned to 8 patients. These results demonstrate the regular occurrence of single- / multidrug-resistant C. glabrata isolates in Germany. Phenotypic resistance testing can lead to misclassification of susceptible isolates. FKS genotyping, on the other hand, is a useful tool for identifying resistant strains. However, in rare cases, echinocandin resistance without a genotypic correlate seems to be possible. KW - Resistenzbestimmung KW - Candida KW - Multidrug-Resistenz KW - Anidulafungin KW - Micafungin KW - Invasive Mykosen KW - Invasive Fungal Infections KW - C. glabrata KW - Multidrug-Resistenzen KW - Antimykotika KW - Mikrodilution KW - Anidulafungin KW - MDR KW - Susceptibility Testing KW - FKS-genes Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-275840 ER - TY - JOUR A1 - Stijnis, Kees A1 - Dijkmans, Anneke C. A1 - Bart, Aldert A1 - Brosens, Lodewijk A. A. A1 - Muntau, Birgit A1 - Schoen, Christoph A1 - Barth, Thomas F. A1 - van Gulik, Thomas A1 - van Gool, Tom A1 - Grobusch, Martin P. A1 - Tappe, Dennis T1 - Echinococcus vogeli in Immigrant from Suriname to the Netherlands JF - Emerging Infectious Diseases KW - alveolar echinococcosis KW - monoclonal antibody KW - multilocularis Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143953 VL - 21 IS - 3 ER - TY - GEN A1 - Tort, Jose F. A1 - Mitreva, Makedonka A1 - Brehm, Klaus R. A1 - Rinaldi, Gabriel T1 - Editorial: Novel Frontiers in Helminth Genomics T2 - Frontiers in Genetics N2 - No abstract available. KW - flatworm KW - nematodes KW - genomics KW - helminths KW - neglected diseases Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-210209 SN - 1664-8021 VL - 11 IS - 791 ER - TY - THES A1 - Schäfer, Daniel T1 - Eine Punktmutation in saeS ist verantwortlich für die veränderte Stressantwort von Staphylococcus aureus Newman gegenüber Desinfektionsmitteln T1 - A point mutation in saeS is responsible for altered stress response of Staphylococcus aureus Newman to biocides N2 - Staphylococcus aureus reagiert auf veränderte Umweltbedingungen wie Hitze, pH und Chemikalien mit Hilfe globaler Regulatoren wie dem Sae (S. aureus exoprotein expression) Zweikomponenten-System. Subinhibitorische Konzentrationen einiger Antibiotika können die Expression von Virulenzfaktoren erhöhen. In dieser Arbeit wurde die Stressantwort von S. aureus auf subletale Konzentrationen des geläufigen Desinfektionsmittels Perform® untersucht. Dazu wurden biochemische Methoden wie SDS-PAGE und Massen-Spektrometrie sowie molekularbiologische Methoden wie qRT-PCR und Promotoraktivitäts-Assays eingesetzt. Davon abhängige, funktionelle Veränderungen wurden in durchfluss-zytometrischen Invasions-Assays analysiert. Perform wirkt durch die Bildung von reaktiven Sauerstoff-Spezies (ROS). Das Wachstum von S. aureus in Medien mit subletalen Konzentrationen von Perform verringerte in den Stämmen 6850, COL und ISP479C die Expression mehrerer Proteine, wohingegen im Stamm Newman eine gesteigerte Expression mehrerer Proteine festgestellt werden konnte. In der Literatur werden diese vermehrt exprimierten Proteine als sae-abhängig beschrieben. Der Effekt von Perform konnte durch das im Desinfektionsmittel enthaltene Detergenz SDS nachgeahmt werden, jedoch nicht durch Paraquat oder weitere Detergenzien wie Triton X-100 oder Tween 20. Eine Solubilisierungsreaktion durch die Detergenz-Wirkung konnte ausgeschlossen werden, da der beobachtete Effekt von lebenden Bakterien abhängt. Für Eap (extracellular adherence protein) konnte die deutlichste Steigerung der Proteinexpression festgestellt werden und eine Transkriptionsanalyse bestätigte die gesteigerte Eap-Expression. Die Promotoraktivität des sae Promotors P1 wurde sowohl durch Perform als auch durch SDS verstärkt. Die Anwesenheit von Perform und SDS hatte auch funktionelle Änderungen zur Folge: In durchflusszytometrischen Experimenten erhöhte sich beispielsweise die Invasivität auf das 2,5- bzw. 3,2-fache und die beobachteten Unterschiede konnten durch Lysostaphin Protektions Versuche bestätigt werden. Weiterhin konnte gezeigt werden, dass die gesteigerte Invasivität in Stamm Newman von Eap und dem sae-System abhängig war, während agr, sarA, sigB und FnBPs keinen entscheidenden Einfluss auf die Invasivität hatten. In dieser Arbeit wurde außerdem aufgedeckt, dass die Besonderheit des Stammes Newman durch eine Mutation in saeS (Sensor-Histidinkinase) bedingt war. Obwohl postuliert wird, dass diese Punktmutation ein konstitutiv aktiviertes sae System zur Folge hat, konnte die hohe sae Aktivität durch Perform und SDS jedoch noch weiter gesteigert werden. Durch den Austausch des gesamten sae-Operons konnte gezeigt werden, dass sich der Stamm Newman saeISP479C wie der Stamm ISP479C, und der Stamm ISP479C saeNewman sich analog zu Stamm Newman verhielt. Zusammenfassend kann aus den vorliegenden Ergebnissen geschlussfolgert werden, dass ein Aminosäurenaustausch in der Sensor-Histidinkinase SaeS des Stammes Newman verantwortlich für die gesteigerte Expression von Eap und die daraus resultierende gesteigerte Invasivität nach der Inkubation mit subletalen Konzentrationen von Perform und SDS ist. Diese Daten können dazu beitragen, die Virulenzmechanismen im Stamm Newman, speziell die Rolle des Sae-Systems, aber auch die der generellen Regulation, besser verstehen zu können. N2 - Staphylococcus aureus copes with changing environmental conditions like heat, pH and chemicals by utilizing global regulators such as the Sae (S. aureus exoprotein expression) two-component signaling system. Subinhibitory concentrations of some antibiotics were shown to increase virulence factor expression. Here, we investigated the S. aureus stress response to sublethal concentrations of the commonly used biocide, Perform®. Therefore biochemical methods including SDS-PAGE and mass spectrometry as well as molecular biological methods like qRT-PCR and promoter activity assays, were used. Additionally, functional differences were analyzed by flow cytometric invasion assays. Perform, acting through the production of reactive oxygen species, generally downregulated the expression of extracellular proteins in strains 6850, COL, ISP479C, but upregulated these proteins in Newman. All upregulated proteins were sae-dependent. Whereas the Perform component SDS mimicked the biocide effect, paraquat or other detergents, as Triton X-100 or Tween 20 did not. A solubilisation by the detergents could be excluded due to the effect´s requirement of live bacteria. Eap (extracellular adherence protein) was most prominently augmented. Upregulation of eap was confirmed by qRT-PCR. Promoter activity of the sae promoter P1 was increased by Perform and SDS. Flow cytometric analysis revealed that both substances enhanced cellular invasiveness 2.5-fold and 3.2-fold, respectively, and the increased invasiveness could be validated by a lysostaphin protection assay. Furthermore, the increased invasiveness was dependent on Eap and the sae system, whereas agr, sarA, sigB and FnBPs had no major effect in strain Newman. This unique response pattern was due to a point mutation in SaeS, as demonstrated by allele swapping. Newman-saeSISP479C behaved like ISP479C, whereas saeSNewman rendered ISP479C equally responsive as Newman. The point mutation is said to lead to a constitutively active sae-system, but with Perform and SDS we were able to further enhance the already high sae-activity. Taken together, an amino acid-substitution in the sensor histidine kinase SaeS of strain Newman was shown to be responsible for the increased expression of Eap upon exposure to sublethal Perform and SDS concentrations, leading to increased Eap-dependent cellular invasiveness. These data may be important for a deeper understanding and further analyzing the virulence mechanism in strain Newman, especially the role of the sae-system but also the general regulation. KW - Desinfektion KW - Staphylococcus aureus KW - Stressreaktion KW - disinfection KW - Staphylococcus aureus KW - stress response Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-42875 ER - TY - THES A1 - Jördens, Markus Sebastian T1 - Einfluss des Komplementsystems und der neuartigen Meningokokken-Vakzine 4CMenB auf cnl-Meningokokken T1 - Influence of the complement system and the novel meningococci-vaccine 4CMenB on cnl-meningococci N2 - In dieser Arbeit wurden verschiedene Vakzine-relevante Oberflächenantigene von cnl-Meningokokken typisiert und die Interaktion von cnl-Meningokokken mit dem Komplementsystem, v.a. mit dessen Hauptregulatoren fH und C4bp, analysiert. Mit den gewonnenen Daten sollten Schlussfolgerungen bzgl. der erwarteten Wirkung von 4CMenB, einem 2013 in Deutschland eingeführten und auf Meningokokken der Serogruppe B abzielenden Impfstoff, auf cnl-Meningokokken gezogen werden. Des Weiteren sollte die Interaktion der natürlicherweise unbekapselten cnl-Meningokokken, die als apathogen und möglicherweise günstig für die Entwicklung einer natürlichen Immunität eingeschätzt werden, untersucht werden. Eine Auswahl von cnl-Meningokokken-Stämmen, die die genetische Variabilität dieser Bakterienpopulation abbilden, wurde mittels PCR (porA, porB, fetA, opc, fHbp, nhba und nadA) oder Western Blot-Analyse (Opc) typisiert. Hierbei konnte eine deutliche Assoziation einzelner Allele zu klonalen Komplexen gezeigt werden. Allerdings lässt die Analyse bezweifeln, dass cnl-Meningokokken durch Bexsero-induzierte Antikörper erkannt werden, da ihr Antigenmuster stark von den Vakzineantigenen abweicht. Unklarheit herrscht lediglich bzgl. des Antigens NhbA. In der Folge wurde die fH- und C4bp-Bindung bei cnl-Meningokokken mittels Durchflusszytometrie untersucht. Es konnte beobachtet werden, dass im Vergleich zu fH bzw. C4bp bindenden Kontrollstämmen die Bindung der Hauptregulatoren des Komplementsystems an cnl-Meningokokken sehr gering ist. Weiterhin konnte gezeigt werden, dass cnl-Meningokokken eine sehr geringe Serumresistenz in vitro haben, was ebenfalls für eine schwache Akquirierung der Komplementregulatoren spricht. Dieser Befund unterstreicht die apathogene Natur der Bakterien. Er zeigt aber auch, dass mit herkömmlichen Methoden wie dem Serumbakterizidietest, der bei bekapselten Stämmen angewendet wird, funktionelle Aussagen bzgl. der Wirkung bakterizider Antikörper, die durch Impfstoffe auf Proteinbasis induziert werden, nur schwer zu tätigen sein werden. Sehr geringe Komplementmengen müssten eingesetzt werden oder alternative Verfahren wie die Opsonophagozytose Anwendung finden. N2 - In this study we typed Vaccine-relevant outer membrane antigens of cnl-meningococci. Furthermore we analysed the interactions of cnl-meningococci with the complement System, especially with the main Regulators factor H and C4bp. The data should help to estimate the impact of 4CMenB, a vaccine against meningococci of serogroup B which was introduced to the german market in 2013, on cnl-meningococci. In addition we examined the interactions of the complemet system with cnl-meningocicci, which are supposed to be apathogen and maybe beneficial for the development of natural immunity. A selection of cnl-meningococci which represent the genetical variability of that bacteria Population was typed for outer membrane Proteins by PCR (porA, porB, fetA, opc, fHbp, nhba, nadA) or western-blot (opc). A close assotiation of allels to clonal complexes could be shown. It is likely that cnl-meningococci are not detected by Bexsero-induced antibodies as their antigen pattern differs from the vaccine Antigens. The only Antigen which ould be detected is NhbA. Factor H and C4bp-binding to cnl-meningococci was examined using flow cytometry Analysis. The binding of fH or C4bp to cnl-meningococci was significantly lower as to fH- or C4cb-binding controll strains. Furthermore serum resistance of cnl-meningococci in vitro is low, which is also an indicator for weak binding of Regulators of the complement System. This finding underlines the apathogen nature of cnl-meningococci. It also indicates the problem of serum bactericidity tests to assess the impact of antibodies induced by protein based vaccines. KW - Meningoencephalitis KW - Komplement KW - Impfstoff KW - Faktor H KW - C4bp KW - cnl-Meningokokken KW - fHbp KW - nhba Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147071 ER - TY - THES A1 - Middendorf, Barbara T1 - Einfluss von Melarsoprol in der Therapie der afrikanischen Trypanosomiasis auf den Glukosemetabolismus des Menschen T1 - Influence of Melarsoprol in therapy of african Trypanosomiasis on glucosemetabolism in humans N2 - Die afrikanische Schlafkrankheit füht unweigerlich zum Tod wenn sie unerkannt und somit unbehandelt bleibt. Zur Therapie stehen nur sehr wenige Medikamente zur Verfügung, wovon die meisten bereits seit mehr als 50 Jahren im Einsatz sind. Unter der Therapie treten in ca. 5-10% der Fälle Enzephalopathien auf, die in vielen Fällen tödlich verlaufen. Bisher ist nicht sicher, wie der dahinterstehende Pathomechanismus verläuft. Zu dieser Frage wurden Untersuchungen des Glukosemetabolismus an Patienten im 2. Stadium der Schlafkrankheit durchgeführt. Es zeigte sich ein signifikanter Anstieg des durchschnittlichen Glukoseniveaus im Verlauf der Therapie. Des weiteren wurden unterschiedliche Verläufe von arzneimittel-induzierter Enzephalopathie klinisch beobachtet und beschrieben. N2 - Human african Trypanosomiasis is a letal desease if left untreated. Most of the medicals used in late stage trypanosomiasis are older than 50 years. In 5-10% of the patients treatment induced encephalopathies occur which often lead to death. Therefore we investigated the glucosemetabolism in late stage patients treated with melarsoprol. a significant increasion of the blood glucose level was shown. Further clinical descriptions of treatment induced encephalopathies were made. KW - Trypanosomiasis KW - Schlafkrankheit KW - Trypanosoma brucei gambiense; Melarsoprol KW - Trypanosomiasis KW - sleeping sickness KW - trypanosoma KW - tsetse-flies Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-28312 ER - TY - THES A1 - Heinen, Florian T1 - Einfluss von Neisseria meningitidis auf Tight-Junctions in humanen mikrovaskulären Hirnendothelzellen (HBMEC) T1 - Influence of Neisseria meningitidis on tight junction proteins of human brain microvascular endothelial cells (HBMEC) N2 - Neisseria meningitidis ist mit jahrlich etwa 700.000 Erkrankungsfallen weltweit und einer Mortalitat von circa 7% einer der häufigsten Ausloser der bakteriellen Hirnhautentzündung. Der entscheidende Schritt zur Auslosung einer Meningitis ist die Uberwindung der Blut-Hirn-Schranke. Diese im menschlichen Korper einmalig dichte Barriere wird maßgeblich durch Tight-Junctions spezialisierter Endothelzellen der Hirnkapillaren aufrecht erhalten. Ob N. Meningitidis diese Barriere auf einem parazellulären oder transzellulärem Weg uberwindet, ist nicht vollstandig geklart. In dieser Arbeit wurde der Einfluss von N. meningitidis auf die Tight-Junction Proteine Occludin und ZO-1 unter Nutzung des HBMEC Zellkulurmodelles untersucht. Neben einer verminderten Genexpression von Occludin zeigte sich dabei eine Abspaltung eines 50 kDa Fragmentes von Occludin. Gleichzeitig konnte eine Umverteilung von Occludin von den Zellgrenzen in das Zytoplasma beobachtet werden. ZO-1 hingegen wurde weder in seiner Exprimierung, noch in seiner intrazellularen Verteilung beeinflusst. Mittels eines in dieser Arbeit etablierten Assays zur Bestimmung der Permeabilitat eines HBMEC-Monolayer als vereinfachtes in-vitro Modell der Blut-Hirn-Schranke konnte bestatigt werden, dass durch die Beeinflussung von Tight-Junction Proteinen die parazellulare Permeabilitat steigt. In weiteren Analysen konnten diese Prozesse auf eine gesteigerte Aktivitat von Matrixmetalloproteinase 8 zurückgefuhrt werden. Die Ergebnisse dieser Arbeit zeigen einen neuen Mechanismus auf, durch den N. meningitidis im Stande ist, die-Hinr-Schranke auf einem parazellulärem Weg zu überwinden. N2 - Neisseria meningitidis is a leading cause of bacterial meningitis with about 700.000 cases per year and a mortality of approximately 7%. A crucial step in the pathogenesis of meningococcal meningitis is the crossing of the blood-brain barrier (BBB). This barrier mainly consists of tight junctions of the microvascular endothelial cells. It remains unclear whether N. meningitidis passes the BBB by a paracellular or transcellular route. In this work the influence of N. meningitidis on the tight junction proteins occludin and ZO-1 was investigated by using the HBMEC cell-culture model. Using QRT-PCR a reduced expression of occludin was seen, western-blot analyses showed a cleavage of occludin into a fragment of 50 kDA. Immonulourescence further showed a complete dissociation of occludin from the cell membrane, whereas ZO-1 was not influenced. By establishing a permeability-assay an increased permeability of the HBMEC monolayer after infection with N. meningitidis was demonstrated. Further work showed, that these effects are dependent of an increased activity of matrix metalloproteinase-8. These results reveal a new mechanism that could enable N. meningitidis to cross the BBB by a paracellular route. KW - Neisseria meningitidis KW - Tight junction KW - Occludin KW - Blut-Hirn-Schranke KW - Neisseria meningitidis KW - Tight junction KW - Occludin KW - Blood-Brain Barrier Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-71631 ER - TY - THES A1 - Karch, André T1 - Einfluss von Polymorphismen im penA-Gen auf das Resistenzverhalten von Neisseria lactamica und Neisseria meningitidis T1 - Impact of penA-polymorphisms on penicillin resistance of Neisseria lactamica and Neisseria meningitidis N2 - Wie das pathogene Bakterium Neisseria meningitidis kolonisiert auch Neisseria lactamica als Kommensale den oberen Nasopharynx des Menschen. Penicillin G ist ein first-line-Therapeutikum gegen Meningokokkeninfektionen. Reduzierte Empfindlichkeit gegenüber Penicillin wird bei Meningokokken durch Mutationen im penA-Gen verursacht. Horizontaler Gentransfer zwischen den verschiedenen Neisseria spp. wurde auch für das penA-Gen beschrieben. Ziel dieser Arbeit war daher eine phänotypische und genotypische Analyse der Penicillinresistenz von N. lactamica. Aus den Versuchen sollten Prognosen über die zukünftige Resistenzentwicklung von Meningokokken abgeleitet werden. Die phänotypische Analyse von 123 N. lactamica-Stämmen (MIC [Minimum inhibitory concentration]-Bereich: 0,064 – 2,0 µg/ml, Median: 0,38 µg/ml) und 129 N. meningitidis- Stämmen (MIC-Bereich: 0,016 – 0,25 µg/ml, Median: 0,064 µg/ml) zeigte signifikant höhere MIC-Werte gegenüber Penicillin G bei den N. lactamica-Stämmen als bei den untersuchten Meningokokken. Bei Meningokokken sind Polymorphismen (fünf spezifische Mutationen betreffend) im penA-Gen (kodiert für das PBP2 (penicillin binding protein 2)) für verminderte Penicillinsensibilität verantwortlich, weshalb der betroffene Abschnitt des penA-Gens in allen N. lactamica-Stämmen und N. meningitidis-Stämmen untersucht und mit den bekannten Allelen der penA-Datenbank verglichen wurde. Bei den 123 N. lactamica-Stämmen konnten 60 verschiedene penA-Allele nachgewiesen werden, wovon 51 neu in die internationale penA-Datenbank eingefügt werden konnten. Im Gegensatz zu Meningokokken trugen die N. lactamica-Stämme entweder drei oder fünf der für intermediär resistente Meningokokken charakteristischen Mutationen im penA-Gen. N. lactamica-Stämme mit fünf Mutationen (MIC-Bereich: 0,25 – 2,0 µg/ml, Median: 0,5 µg/ml) zeigten signifikant höhere MIC-Werte als Stämme mit drei Mutationen (MIC-Bereich: 0,064 – 0,38 µg/ml, Median: 0,125 µg/ml), aber auch als Meningokokken mit fünf Mutationen (MIC-Bereich: 0,064 – 0,25 µg/ml, Median: 0,125 µg/ml). Eine phylogenetische Analyse aller in der penA-Datenbank hinterlegten Allele zusammen mit den 51 neuen dieser Studie ergab, dass die Allele mit fünf Mutationen unabhängig von der Spezies eine gemeinsame phylogenetische Linie bildeten, während sowohl die Allele mit drei Mutationen (N. lactamica) als auch die ohne Mutationen (N. meningitidis) jeweils eine separate phylogenetische Gruppe formten. Im Rahmen von in vitro-Transformationen mit chromosomaler DNA von N. lactamica konnte der MIC-Wert des Penicillin-sensiblen Meningokokkenstamms 14 in einem single-step-Ereignis durch Übernahme des betreffenden penA-Gens von N. lactamica erhöht werden. Allerdings konnten nur MIC-Werte erreicht werden, die mit intermediär-sensiblen Meningokokken vergleichbar waren und somit weit unter den MIC-Werten der benutzten N. lactamica-Stämme lagen. Dieser Befund legt nahe, dass erhöhte MIC-Werte bei N. lactamica wie auch bei Meningokokken mit Mutationen in der Transpeptidaseregion des PBP2 assoziiert sind. Jedoch sind die im Vergleich zu Meningokokken generell höheren MIC-Werte bei N. lactamica auf andere Faktoren zurückzuführen, die bei N. lactamica eine verminderte Empfindlichkeit gegenüber Penicillin bedingen. In den in vitro-Experimenten der vorliegenden Studie konnten diese Faktoren nicht auf Meningokokken übertragen werden. Demnach kann eine Co-Kolonisation mit N. lactamica zwar die MIC-Werte von Meningokokken erhöhen, das Erreichen von bei N. lactamica beobachteten Resistenzniveaus ist allerdings auf diesem Wege nicht möglich. Es ist somit nicht zu befürchten, dass Meningokokken – wie bei Pneumokokken beobachtet – über kommensale Spezies der gleichen Gattung eine massive Reduktion der Empfindlichkeit gegenüber Penicillin entwickeln werden. N2 - Neisseria lactamica colonises the human upper nasopharynx together with the pathogen bacteria Neisseria meningitidis. Penicillin G remains a first line therapy against meningococcal disease. Reduced penicillin susceptibility in N. meningitidis is caused by mutations in penA-gene. Horizontal gene transfer between Neisseria spp. has been described for the penA-gene as well. The aim of this study was to provide a phenotypic and genotypic analysis of penicillin resistance in N. lactamica. Moreover, implications about future developments of penicillin resistance in meningococci should be derived. A phenotypic analysis of 123 N. lactamica-isolates (MIC [Minimum inhibitory concentration]-range: 0.064 – 2.0 µg/ml, median: 0.38 µg/ml) and 129 N. meningitidis-isolates (MIC-range: 0.016 – 0.25 µg/ml, median: 0,064 µg/ml) showed significantly higher MIC values in N. lactamica. Five specific polymorphisms in penA-gene (encoding for PBP2 (penicillin binding protein 2)) are responsible for reduced penicillin susceptibility in meningococci. Therefore the penA-gene of all isolates in this study was analysed and compared with the registered alleles in the penA-database. Sixty different penA-alleles were found in the 123 N. lactamica-isolates of this study. Fifty-one of these alleles could not be found in the penA-database and were added to the database during this study. Unlike N. meningitidis, the analysed N. lactamica-isolates harbored either three or five of the mutations in penA-gene, which are typical for intermediate susceptible meningococci. N. lactamica-isolates with five mutations (MIC-range: 0.25 – 2.0 µg/ml, median: 0.5 µg/ml) showed significantly higher MIC-values than N. lactamica-isolates with three mutations (MIC-range: 0.064 – 0.38 µg/ml, median: 0.125 µg/ml), but also than meningococci with five mutations (MIC-range: 0.064 – 0.25 µg/ml, median: 0.125 µg/ml). A phylogenetic analysis of the 51 new alleles in this study together with all alleles of the penA-database showed, that alleles with five mutations grouped together independently of the species they came from, whereas alleles with three mutations (N. lactamica) as well as alleles without mutations (N. meningitidis) formed separate phylogenetic lines. In vitro-transformations with chromosomal DNA from N. lactamica could raise the MIC-value of the susceptible meningococcus a14 in a single step event by receiving the penA-allele from N. lactamica. However, the MIC-values observed in these transformants were only comparable to those in intermediate susceptible meningococci but considerably below the values of the N. lactamica-isolates used for the transformation. The results of this study showed that high MIC-values in N. lactamica as well as in N. meningitidis are associated with mutations in the transpeptidase region of PBP2. However, the generally higher MIC-values in N. lactamica must be attributed to other factors. These factors could not be transferred to meningococci in this study. As a result of this study it can be stated that co-colonisation with N. lactamica might raise MIC-values in N. meningitidis. However, considerable reductions of penicillin susceptibility by horizontal gene transfer from commensal spezies of the same genus (as observed in pneumococci) cannot be expected for N. meningitidis. KW - Neisseria meningitidis KW - Penicillin G KW - Sensibilität KW - Neisseria lactamica KW - penA KW - Neisseria meningitidis KW - Neisseria lactamica KW - penicillin resistance KW - penA Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-71852 ER - TY - JOUR A1 - Brehm, Klaus A1 - Komguep Nono, Justin A1 - Lutz, Manfred B. T1 - EmTIP, a T-Cell Immunomodulatory Protein Secreted by the Tapeworm Echinococcus multilocularis Is Important N2 - Background Alveolar echinococcosis (AE), caused by the metacestode of the tapeworm Echinococcus multilocularis, is a lethal zoonosis associated with host immunomodulation. T helper cells are instrumental to control the disease in the host. Whereas Th1 cells can restrict parasite proliferation, Th2 immune responses are associated with parasite proliferation. Although the early phase of host colonization by E. multilocularis is dominated by a potentially parasitocidal Th1 immune response, the molecular basis of this response is unknown. Principal Findings We describe EmTIP, an E. multilocularis homologue of the human T-cell immunomodulatory protein, TIP. By immunohistochemistry we show EmTIP localization to the intercellular space within parasite larvae. Immunoprecipitation and Western blot experiments revealed the presence of EmTIP in the excretory/secretory (E/S) products of parasite primary cell cultures, representing the early developing metacestode, but not in those of mature metacestode vesicles. Using an in vitro T-cell stimulation assay, we found that primary cell E/S products promoted interferon (IFN)-γ release by murine CD4+ T-cells, whereas metacestode E/S products did not. IFN-γ release by T-cells exposed to parasite products was abrogated by an anti-EmTIP antibody. When recombinantly expressed, EmTIP promoted IFN-γ release by CD4+ T-cells in vitro. After incubation with anti-EmTIP antibody, primary cells showed an impaired ability to proliferate and to form metacestode vesicles in vitro. Conclusions We provide for the first time a possible explanation for the early Th1 response observed during E. multilocularis infections. Our data indicate that parasite primary cells release a T-cell immunomodulatory protein, EmTIP, capable of promoting IFN-γ release by CD4+ T-cells, which is probably driving or supporting the onset of the early Th1 response during AE. The impairment of primary cell proliferation and the inhibition of metacestode vesicle formation by anti-EmTIP antibodies suggest that this factor fulfills an important role in early E. multilocularis development within the intermediate host. KW - T Cells KW - primary cells KW - parasitic diseases KW - vesicles KW - larvae KW - immunoprecipitation KW - host-pathogen interactions KW - immune response Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111407 ER - TY - JOUR A1 - Koch, J. A1 - Hellenbrand, W. A1 - Schink, S. A1 - Wichmann, O. A1 - Carganico, A. A1 - Drewes, J. A1 - Kruspe, M. A1 - Suckau, M. A1 - Claus, H. A1 - Marcus, U. T1 - Evaluation of a temporary vaccination recommendation in response to an outbreak of invasive meningococcal serogroup C disease in men who have sex with men in Berlin, 2013-2014 JF - Eurosurveillance N2 - Meningococcal serogroup C (MenC) vaccination of men who have sex with men (MSM) was temporarily recommended to control an outbreak of invasive MenC disease among MSM in Berlin in 2012–2013. Vaccination was offered to HIV-infected MSM free of charge; others had to request reimbursement or pay out of pocket. We aimed to assess (i) awareness and acceptance of this recommendation through an online survey of MSM, (ii) implementation through a survey of primary care physicians and analysis of vaccine prescriptions, and (iii) impact through analysis of notified cases. Among online survey respondents, 60% were aware of the recommendation. Of these, 39% had obtained vaccination (70% of HIV-infected, 13% of HIV-negative/non-tested MSM). Awareness of recommendation and vaccination were positively associated with HIV infection, primary care physicians’ awareness of respondents’ sexual orientation, and exposure to multiple information sources. Most (26/30) physicians informed clients about the recommendation. Physicians considered concerns regarding reimbursement, vaccine safety and lack of perceived disease risk as primary barriers. After the recommendation, no further outbreak-related cases occurred. To reach and motivate target groups, communication of a new outbreak-related vaccination recommendation should address potential concerns through as many information channels as possible and direct reimbursement of costs should be enabled. KW - Meningococcal serogroup C Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165070 VL - 21 IS - 5 ER - TY - JOUR A1 - Straub, Anton A1 - Vollmer, Andreas A1 - Lâm, Thiên-Trí A1 - Brands, Roman C. A1 - Stapf, Maximilian A1 - Scherf-Clavel, Oliver A1 - Bittrich, Max A1 - Fuchs, Andreas A1 - Kübler, Alexander C. A1 - Hartmann, Stefan T1 - Evaluation of advanced platelet-rich fibrin (PRF) as a bio-carrier for ampicillin/sulbactam JF - Clinical Oral Investigations N2 - Objectives Mechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early surgical intervention is indicated. However, surgery often faces complications such as wound healing disorders. The application of platelet-rich fibrin (PRF) after necrosectomy between bone and mucosa may constitute a promising approach to improve surgical results. An aspect that was not investigated until now is that PRF acts as a “bio-carrier” for antibiotics previously applied intravenously. Materials and methods We investigated the antimicrobial properties of PRF in 24 patients presenting ONJ undergoing systemic antibiosis with ampicillin/sulbactam. We measured the concentration of ampicillin/sulbactam in plasma and PRF and performed agar diffusion tests. Ampicillin/sulbactam was applied intravenously to the patient 10 minutes for blood sampling for PRF. No further incorporation of patients’ blood or PRF product with antibiotic drugs was obtained. Four healthy patients served as controls. Results Our results revealed that PRF is highly enriched with ampicillin/sulbactam that is released to the environment. The antibiotic concentration in PRF was comparable to the plasma concentration of ampicillin/sulbactam. The inhibition zone (IZ) of PRF was comparable to the standard ampicillin/sulbactam discs used in sensitivity testing. Conclusions The results of our study demonstrated that PRF is a reliable bio-carrier for systemic applied antibiotics and exhibits a large antimicrobial effect. Clinical relevance We describe a clinically useful feature of PRF as a bio-carrier for antibiotics. Especially when applied to poorly perfused tissues and bone such as in ONJ, the local release of antibiotics can reduce wound healing disorders like infections. KW - osteonecrosis of the jaw KW - osteoradionecrosis KW - antiresorptive drug-related osteonecrosis of the jaw KW - ARONJ KW - oral microbiome KW - agar diffusion test Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324515 VL - 26 IS - 12 ER - TY - THES A1 - Fuß, Antje T1 - Evaluierung des Nachweises von Schistosoma mansoni DNA mittels Real-Time PCR in verschiedenen humanen Proben sowie den Zwischenwirtschnecken in einer Hochprävalenzregion am Viktoriasee in Tansania T1 - Evaluation of the detection of Schistosoma mansoni DNA by real-time PCR in different human samples and the intermediate host snails in a high prevalence region at Lake Victoria in Tanzania N2 - Die Schistosomiasis ist nach wie vor eine der häufigsten parasitären Erkrankungen der Welt und verursacht erhebliche gesundheitliche und wirtschaftliche Folgen, insbesondere in ärmeren, ländlichen Regionen. Durch Immunreaktionen auf die im Wirt abgelegten Eier des Parasiten können sich chronische Verlaufsformen manifestieren. Dabei kann es zu irreversiblen Schäden kommen. Um dies zu verhindern sind eine frühe und sichere Diagnose sowie eine Behandlung mit Praziquantel (PZQ) unabdingbar. Zudem spielt der zuverlässige Nachweis der Schistosomiasis eine Schlüsselrolle bei der Überwachung, Prävention und Kontrolle der Erkrankung. In epidemiologischen Studien findet am häufigsten die mikroskopische Kato-Katz (KK)-Methode zum Nachweis von Schistosoma mansoni Eiern im Stuhl Anwendung. Dieses Verfahren ist äußerst spezifisch und bietet die Möglichkeit der Quantifizierung, wodurch die Intensität der vorliegenden Infektion bestimmt werden kann. Die Sensitivität der Testmethode ist jedoch nur moderat, insbesondere bei einer niedrigen Infektionsintensität. Zudem kann eine Infektion erst nach der Präpatenzzeit nachgewiesen werden. Der ebenfalls häufig eingesetzte urinbasierte Point-of-Care Circulating Cathodic Antigen (POC-CCA)-Test weist zwar eine höhere Sensitivität aber geringere Spezifität als das KK-Verfahren auf. Als hochsensitive und sehr spezifische Methode zur Diagnose der Schistosomiasis hat sich der Nachweis von Schistosoma-spezifischer DNA mittels Real-Time PCR herausgestellt. Allerdings wird für die Durchführung dieser Technik ein gut ausgestattetes Labor benötigt, das sich in der Regel nicht in unmittelbarer Nähe zum Patienten im Feld befindet. Daher ist es besonders wichtig, über praktikable und schnelle Konservierungsmethoden zu verfügen, die bevor die Extraktion und Amplifikation der DNA stattfindet, einen einfachen Transport und eine einfache Lagerung des Probenmaterials ermöglichen. Das Ziel des ersten Teils der vorliegenden Arbeit war, die Sensitivität und Spezifität der klassischerweise verwendeten KK-Methode und des POC-CCA-Tests mit der Real-Time PCR- Methode unter Verwendung von Stuhlproben, Urinproben, Serumproben sowie auf Filterpapier getrocknete Blutproben (dried blood spots – DBSs) zu vergleichen. Zudem wurde die Anwendbarkeit der Real-Time PCR aus Serum- und Urinproben zur Therapiekontrolle überprüft. Die dazu notwendigen Studien wurden alle in der Region Mwanza in Tansania durchgeführt, welche als hochendemisch für S. mansoni gilt. Für die Untersuchungen zur stuhlbasierten Real-Time PCR wurden als Studienteilnehmer Schulkinder gewählt. Aufgrund der erforderlichen Blutabnahme wurden die anderen Teilstudien nur mit erwachsenen Probanden durchgeführt. Unter Verwendung der KK-Methode als Goldstandard erzielten die Real-Time PCR aus Stuhlproben und der POC-CCA-Test sehr hohe Sensitivitäten von 99,5% bzw. 89,7%, jedoch nur geringe Spezifitäten von 29,55% und 22,73%. Die KK-Methode weist bekanntermaßen nur eine geringe bis moderate Sensitivität auf und ist daher nicht gut als Referenz geeignet. Deshalb wurde zusätzlich eine latente Klassenanalyse angewandt, um die tatsächlich Erkrankten zu ermitteln und anhand dieser die diagnostische Güte der verwendeten Tests zu bestimmen. Hier zeigte der POC-CCA-Test die höchste Sensitivität (99,5%) sowie eine Spezifität von 63,4%. Der Real-Time PCR-Test hatte eine Sensitivität von 98,7% und die höchste Spezifität (81,2%). Die Spezifität der KK-Technik betrug 72,8%, die Sensitivität war signifikant niedriger (89,7%) als bei den anderen beiden Methoden. Diese Ergebnisse verdeutlichen, dass der POC-CCA-Schnelltest empfindlicher ist als die KK-Methode und zum Screening von S. mansoni-Infektionen eingesetzt werden kann. Die Stuhl-PCR war zwar ebenfalls hochsensitiv und zeigte unter den drei getesteten Diagnoseverfahren die höchste Spezifität, aber aufgrund der höheren Kosten und der komplizierten Anwendung sollte für epidemiologische Untersuchungen in Hochprävalenzregionen der POC-CCA-Test bevorzugt werden. Bei unklaren Diagnosen kann die Real-Time PCR-Methode als Bestätigungstest Anwendung finden. In der Teilstudie zur serum- und urinbasierten Real-Time PCR in einer endemischen Region vor und nach der Behandlung mit PZQ wurden folgende Ergebnisse erzielt: Unter Verwendung einer kombinierten Referenz aus den Ergebnissen des parasitologischen KK-Tests und / oder der serumbasierten PCR konnte zu Studienbeginn eine Prävalenz von S. mansoni von 77,1% ermittelt werden. In Bezug auf die Sensitivität zeigte der DNA-Nachweis aus Serum (96,3%) und der POC-CCA-Assay (77,8%) die höchsten Ergebnisse. Die urinbasierte Real-Time PCR zeigte die geringste Empfindlichkeit (33,3%). Durch die Behandlung mit Praziquantel wurde eine signifikante Reduktion der S. mansoni Prävalenz erreicht. Zwanzig Wochen nach Therapie konnte durch die KK-Methode keine, mit dem POC-CCA-Test 33,3% und mit der serumbasierten Real-Time PCR 58,3% Infektionen festgestellt werden. Die Analyse der mittels der serumbasierten PCR bestimmten mittleren Ct-Werte im zeitlichen Verlauf zeigte, dass dieser eine Woche nach der Behandlung signifikant abnahm (von 30,3 auf 28) und 20 Wochen später über den Basiswert (34,9) anstieg. Der Ct-Wert ist umgekehrt proportional zur DNA-Ausgangsmenge, die in die PCR eingesetzt wurde. Dies deutet darauf hin, dass kurz nach der Therapie ein DNA-Anstieg zu verzeichnen war und 20 Wochen später weniger DNA als zu Beginn der Studie nachweisbar war. Dieser DNA-Verlauf lässt verschiedene Interpretationsmöglichkeiten zu. Die Daten zeigen jedoch, dass die serumbasierte Real-Time PCR eine ausgezeichnete diagnostische Genauigkeit aufweist. Da die nachgewiesene DNA jedoch keine Rückschlüsse auf das Parasitenstadium zulässt und es sich hierbei auch um DNA aus im Gewebe verbliebenen Eiern oder Reinfektionen handeln könnte, ist diese Methode in Hochprävalenz- Regionen nicht zur Therapiekontrolle geeignet. Die Verwendung von Urin zum DNA-Nachweis erzielte keine vielversprechenden Ergebnisse. Die Sensitivität der Real-Time PCR aus DBSs war ebenfalls sehr gering (45,4%) und kann ohne weitere ausführliche Testung hinsichtlich Lagertemperatur, Lagerdauer, verschiedener Filterpapierarten und Extraktionsmethoden nicht empfohlen werden. Zusammenfassend zeigten die Ergebnisse dieser Studien, dass sowohl die stuhl- als auch die serumbasierte Real-Time PCR bei der Erkennung und Bewertung der Infektionsprävalenz, einem wichtigen Aspekt epidemiologischer Studien, deutlich empfindlicher ist als das mikroskopische KK-Verfahren. Aufgrund des hohen Kosten- und Personalaufwandes und der Notwendigkeit eines gut ausgestatteten Labors wird sich diese Methode aber nicht zum Screening in hochendemischen Ländern durchsetzen. Sie kann jedoch einen Mehrwert bei der Diagnose der Schistosomiasis bieten, vor allem bei frühen oder leichten Infektionen. Zudem kann diese hochsensitive und spezifische Methode als Bestätigungstest bei unklaren Diagnosen herangezogen werden. Im zweiten Teil dieser Arbeit wurden malakologische Untersuchungen zur Identifizierung potenzieller Übertragungsorte für die Schistosomiasis rund um die im Viktoriasee gelegene Insel Ijinga durchgeführt. Diese Analysen fanden innerhalb eines Pilotprojektes zur Eliminierung der Erkrankung auf der Insel Ijinga statt, wobei ein intensiviertes Behandlungsprotokoll, welches die gesamte Inselbevölkerung einschloss, Anwendung fand. Die Kontrolle der Praziquanteleffektivität nach mehreren Behandlungsrunden bringt eine Reihe diagnostischer Herausforderungen mit sich. Hier könnte die Beurteilung der Schistosoma-Infektion in den Zwischenwirtschnecken vor und nach der Therapie als Indikator für den Erfolg der Maßnahme dienen. Zu diesem Zweck erfolgte zunächst eine Baseline-Untersuchung, bei der Schnecken an Uferregionen gesammelt wurden, an denen die Inselbewohner häufigen Wasserkontakt hatten. Die Schnecken wurden anhand morphologischer Merkmale identifiziert und mithilfe der Real-Time PCR-Methode auf Infektionen mit S. mansoni untersucht. Insgesamt wurden 35,4% (279/788) S. mansoni- positive Zwischenwirtschnecken (Biomphalaria) detektiert. Dies verdeutlicht, dass an den meisten Wasserkontaktstellen um die Insel Ijinga ein potentielles Risiko für die Übertragung der Schistosomiasis besteht. Die mithilfe der KK-Methode ermittelte Gesamtprävalenz von S. mansoni in der humanen Bevölkerung betrug 68,9%. Nachdem die Bewohner der Insel viermal mit PZQ behandelt wurden, zeigte sich in der kontinuierlich überwachten Sentinelgruppe eine Reduktion der Prävalenz auf 28,7%. Zu diesem Zeitpunkt wurde ebenfalls die Analyse der Schnecken wiederholt und es konnten 16,8% (57/350) Schnecken mit einer S. mansoni Infektion nachgewiesen werden. Die Reduktion der Infektionshäufigkeit in den Schnecken vor und nach der viermaligen Behandlung der Bevölkerung war signifikant (χ² = 74.335, p < 0,001). Dies deutet darauf hin, dass die intermediären Wirtsschnecken zur Überwachung von Kontrollmaßnahmen verwendet werden können. N2 - Schistosomiasis remains one of the most common parasitic infections in the world, causing significant health and economic consequences, particularly in rural areas. Immune reactions to the parasite's eggs deposited in the host can lead to chronic progression. This may result in to irreversible damage. In order to prevent this, an early and reliable diagnosis and a concomitant therapy will be indispensable. In addition, the reliable detection of schistosomiasis plays a key role in monitoring, prevention and control of the disease. In epidemiological studies, the microscopic Kato-Katz (KK) method is most frequently used to detect eggs in stool. This method is highly specific and offers the possibility of quantification, which allows to determine the intensity of the existing infection. However, especially at low infection intensities, the sensitivity of the test method is rather moderate. Furthermore, infections can only be detected after the prepatent period. The also frequently used urine-based Point-of-Care Circulating Cathodic Antigen (POC-CCA) test shows a higher sensitivity but lower specificity than the KK method. The detection of schistosome-specific DNA through Real-Time PCR has proven to be a highly sensitive and very specific method for the diagnosis of schistosomiasis. However, this assay requires a well-equipped laboratory, which is usually not located in the immediate vicinity of the patient in the field. Therefore, it is particularly important to have practical and rapid preservation methods that allow easy transport and storage of the sample material before DNA extraction and amplification takes place. The aim of the first part of this dissertation was to compare the sensitivity and specificity of the classical KK method and the POC-CCA test with the Real-Time PCR method using stool samples, urine samples, serum samples and blood samples dried on filter paper (dried blood spots – DBS). In addition, tests were conducted regarding the applicability of Real-Time PCR from serum and urine samples for therapy control. The necessary studies were all carried out in the Mwanza region of Tanzania, which is considered to be highly endemic for S. mansoni. Schoolchildren were selected as study participants for the studies on stool-based Real-Time PCR. Due to the required blood collection, the other partial studies were conducted with adults only. Using the KK method as gold standard, the Real-Time PCR from stool samples and the POC-CCA test achieved very high sensitivities of 99.5% and 89.7%, respectively, but only low specificities of 29.55% and 22.73%. The KK method is known to have low to moderate sensitivity and is therefore not well suited as a reference. For this reason, a latent class analysis was carried out to determine the true patients and the diagnostic quality of the tests used. The POC-CCA test showed the highest sensitivity (99.5%) and a specificity of 63.4%. The Real-Time PCR test had a sensitivity of 98.7% and the highest specificity (81.2%). The specificity of the KK technique was 72.8%, the sensitivity was significantly lower (89.7%) than with the other two methods. These results show that the POC-CCA rapid test is more sensitive than the KK method and can be used to screen for S. mansoni infections. Although stool PCR is also highly sensitive and shows the highest specificity of the three diagnostic methods tested, the POC-CCA test should be preferred for epidemiological investigations in high prevalence regions on account of the higher costs and complicated application. If the diagnosis is unclear, the Real-Time PCR method can be used as a confirmatory test. The following results were obtained in the partial study regarding the use of serum and urine-based Real-Time PCR in an endemic region before and after treatment with Praziquantel (PZQ): Using a combined reference of the results of the parasitological KK test and / or the serum-based PCR, a prevalence of S. mansoni of 77.1% could be determined at the beginning of the study. In terms of sensitivity, DNA detection from serum (96.3%) and the POC-CCA assay (77.8%) showed the highest results. Urine-based Real-Time PCR showed the lowest sensitivity (33.3%). Treatment with Praziquantel significantly reduced the prevalence of S. mansoni. Twenty weeks after therapy, no infections could be detected with the KK method, 33.3% with the POC-CCA test and 58.3% with the serum-based Real-Time PCR. Analysis of mean Ct-values determined by serum-based Real-Time PCR over time showed that it decreased significantly (from 30.3 to 28) one week after treatment and increased above the baseline value (34.9) 20 weeks later. The Ct-value is inversely proportional to the initial amount of DNA added to the PCR. This suggests that shortly after therapy there was an increase in DNA and 20 weeks later less DNA was detectable compared to the beginning of the study. This DNA progression offers various interpretation possibilities. However, the data show that serum-based Real-Time PCR has excellent diagnostic accuracy. Yet, since the detected DNA does not allow conclusions to be drawn about the parasite stage and this could also be DNA from eggs remaining in the tissue or reinfections, this method is not suitable for therapy control in high prevalence regions. The use of urine for DNA detection did not yield promising results. The sensitivity of the Real-Time PCR from DBSs was also very low (45.4%) and cannot be recommended without further extensive testing with regard to storage temperature, storage time, different filter paper types and extraction methods. In summary, the results of these studies showed that Real-Time PCR is significantly more sensitive than microscopy in the detection and evaluation of infection prevalence, an important aspect of epidemiological studies. However, due to the high costs and personnel involved and the need for a well-equipped laboratory, this method will not be accepted for screening in high-endemic countries. Yet, it can provide added value in the diagnosis of schistosomiasis, especially in early or light infections. In addition, this highly sensitive and specific method can be used as a confirmatory test for unclear diagnoses. The second part of this dissertation describes malacological investigations to identify potential transmission sites for schistosomiasis around Ijinga Island located on Lake Victoria. These analyses took place as part of a pilot project to eliminate the disease on this island, using an intensified treatment protocol that included the entire island population. The control of Praziquantel effectiveness after several rounds of treatment poses a number of diagnostic challenges. Here, the assessment of the schistosoma infection in the intermediate host snails before and after the therapies could serve as an indicator for the success of the measure. For this purpose, a baseline study was carried out, in which snails were collected from shore regions where the islanders had frequent contact with water. The snails were identified on the basis of morphological characteristics and examined for infections with S. mansoni using the Real-Time PCR method. A total of 35.4% (279/788) S. mansoni positive intermediate host snails (Biomphalaria) were detected. This shows that there is a potential risk of schistosomiasis transmission at most water contact points around Ijinga. The total prevalence of S. mansoni in the human population determined by the KK method was 68.9%. After treating the community with Praziquantel four times, the prevalence of S. mansoni in the continuously monitored sentinel group was reduced to 28.7%. At this time, the analysis of the snails was repeated and 16.8% (57/350) snails with a S. mansoni infection were detected. The reduction in the frequency of infection in the snails before and after the fourfold treatment of the population was significant (χ² = 74,335, p < 0.001). This suggests that the intermediate host snails can be used to monitor control measures. KW - Schistosomiasis KW - Bilharziose KW - Real-time PCR KW - Tansania KW - Trematoden KW - Vernachlässigte Tropenkrankheiten Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-215061 ER - TY - JOUR A1 - Herz, Michaela A1 - Brehm, Klaus T1 - Evidence for densovirus integrations into tapeworm genomes JF - Parasites & Vectors N2 - Background Tapeworms lack a canonical piRNA-pathway, raising the question of how they can silence existing mobile genetic elements (MGE). Investigation towards the underlying mechanisms requires information on tapeworm transposons which is, however, presently scarce. Methods The presence of densovirus-related sequences in tapeworm genomes was studied by bioinformatic approaches. Available RNA-Seq datasets were mapped against the Echinococcus multilocularis genome to calculate expression levels of densovirus-related genes. Transcription of densovirus loci was further analyzed by sequencing and RT-qPCR. Results We herein provide evidence for the presence of densovirus-related elements in a variety of tapeworm genomes. In the high-quality genome of E. multilocularis we identified more than 20 individual densovirus integration loci which contain the information for non-structural and structural virus proteins. The majority of densovirus loci are present as head-to-tail concatemers in isolated repeat containing regions of the genome. In some cases, unique densovirus loci have integrated close to histone gene clusters. We show that some of the densovirus loci of E. multilocularis are actively transcribed, whereas the majority are transcriptionally silent. RT-qPCR data further indicate that densovirus expression mainly occurs in the E. multilocularis stem cell population, which probably forms the germline of this organism. Sequences similar to the non-structural densovirus genes present in E. multilocularis were also identified in the genomes of E. canadensis, E. granulosus, Hydatigera taeniaeformis, Hymenolepis diminuta, Hymenolepis microstoma, Hymenolepis nana, Taenia asiatica, Taenia multiceps, Taenia saginata and Taenia solium. Conclusions Our data indicate that densovirus integration has occurred in many tapeworm species. This is the first report on widespread integration of DNA viruses into cestode genomes. Since only few densovirus integration sites were transcriptionally active in E. multilocularis, our data are relevant for future studies into gene silencing mechanisms in tapeworms. Furthermore, they indicate that densovirus-based vectors might be suitable tools for genetic manipulation of cestodes. KW - Echinococcus KW - Echinococcosis KW - Densovirus KW - Parvovirus KW - Mobile genetic element KW - Gene silencing KW - Stem cell KW - Epigenetic Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202478 VL - 12 ER - TY - JOUR A1 - Taha, Muhamed-Kheir A1 - Claus, Heike A1 - Lappann, Martin A1 - Veyrier, Frédéric J. A1 - Otto, Andreas A1 - Becher, Dörte A1 - Deghmane, Ala-Eddine A1 - Frosch, Matthias A1 - Hellenbrand, Wiebke A1 - Hong, Eva A1 - du Châtelet, Isabelle Parent A1 - Prior, Karola A1 - Harmsen, Dag A1 - Vogel, Ulrich T1 - Evolutionary Events Associated with an Outbreak of Meningococcal Disease in Men Who Have Sex with Men JF - PLoS ONE N2 - Meningococci spread via respiratory droplets, whereas the closely related gonococci are transmitted sexually. Several outbreaks of invasive meningococcal disease have been reported in Europe and the United States among men who have sex with men (MSM). We recently identified an outbreak of serogroup C meningococcal disease among MSM in Germany and France. In this study, genomic and proteomic techniques were used to analyze the outbreak isolates. In addition, genetically identical urethritis isolates were recovered from France and Germany and included in the analysis. Genome sequencing revealed that the isolates from the outbreak among MSM and from urethritis cases belonged to a clade within clonal complex 11. Proteome analysis showed they expressed nitrite reductase, enabling anaerobic growth as previously described for gonococci. Invasive isolates from MSM, but not urethritis isolates, further expressed functional human factor H binding protein associated with enhanced survival in a newly developed transgenic mouse model expressing human factor H, a complement regulatory protein. In conclusion, our data suggest that urethritis and outbreak isolates followed a joint adaptation route including adaption to the urogenital tract. KW - nitrites KW - genome sequencing KW - men who have sex with men KW - meningococcal disease KW - Neisseria meningitidis KW - Neisseria gonorrhoeae KW - mammalian genomics KW - mouse models Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179870 VL - 11 IS - 5 ER - TY - JOUR A1 - Luber, Verena A1 - Lutz, Mathias A1 - Abele-Horn, Marianne A1 - Einsele, Hermann A1 - Grigoleit, Götz Ulrich A1 - Mielke, Stephan T1 - Excretion of Ascaris lumbricoides following reduced‐intensity allogeneic hematopoietic stem cell transplantation and consecutive treatment with mebendazole JF - Transplant Infectious Disease N2 - Here, we present the unique case of a 51‐year‐old German patient with multiple myeloma excreting Ascaris lumbricoides in his stool five weeks after allogeneic hematopoietic stem cell transplantation. Stool analysis remained negative for the presence of eggs, and there was no eosinophilia in the peripheral blood at any time around stem cell transplantation. The patient was commenced on a three‐day treatment with mebendazole, which was well tolerated. No serious interactions with the concomitant post‐transplant medication or negative effects on the hematopoiesis were observed, and the myeloma still is in complete remission. To our knowledge, this is the first report on excretion of A lumbricoides in the context of allogeneic stem cell transplantation. The case is remarkable with view to the fact that the parasite has supposedly survived all courses of myeloma treatment including autologous and allogeneic conditioning. Parasitosis with A lumbricoides has a worldwide prevalence of about a billion and is extremely rare in northern Europe. Possibly the patient got infected during a trip to Egypt years before multiple myeloma was diagnosed. KW - sirolimus KW - mycophenolic acid KW - multiple myeloma KW - mebendazole KW - hematopoietic stem cell transplantation KW - Ascaris lumbricoides Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219608 SN - 1399-3062 VL - 22 IS - 1 ER - TY - JOUR A1 - Nono, Justin Komguep A1 - Pletinckx, Katrien A1 - Lutz, Manfred B. A1 - Brehm, Klaus T1 - Excretory/Secretory-Products of Echinococcus multilocularis Larvae Induce Apoptosis and Tolerogenic Properties in Dendritic Cells In Vitro JF - PLoS Neglected Tropical Diseases N2 - Background: Alveolar echinococcosis, caused by Echinococcus multilocularis larvae, is a chronic disease associated with considerable modulation of the host immune response. Dendritic cells (DC) are key effectors in shaping the immune response and among the first cells encountered by the parasite during an infection. Although it is assumed that E. multilocularis, by excretory/secretory (E/S)-products, specifically affects DC to deviate immune responses, little information is available on the molecular nature of respective E/S-products and their mode of action. Methodology/Principal Findings: We established cultivation systems for exposing DC to live material from early (oncosphere), chronic (metacestode) and late (protoscolex) infectious stages. When co-incubated with Echinococcus primary cells, representing the invading oncosphere, or metacestode vesicles, a significant proportion of DC underwent apoptosis and the surviving DC failed to mature. In contrast, DC exposed to protoscoleces upregulated maturation markers and did not undergo apoptosis. After pre-incubation with primary cells and metacestode vesicles, DC showed a strongly impaired ability to be activated by the TLR ligand LPS, which was not observed in DC pre-treated with protoscolex E/S-products. While none of the larvae induced the secretion of pro-inflammatory IL-12p70, the production of immunosuppressive IL-10 was elevated in response to primary cell E/S-products. Finally, upon incubation with DC and naive T-cells, E/S-products from metacestode vesicles led to a significant expansion of Foxp3+ T cells in vitro. Conclusions: This is the first report on the induction of apoptosis in DC by cestode E/S-products. Our data indicate that the early infective stage of E. multilocularis is a strong inducer of tolerance in DC, which is most probably important for generating an immunosuppressive environment at an infection phase in which the parasite is highly vulnerable to host attacks. The induction of CD4+CD25+Foxp3+ T cells through metacestode E/S-products suggests that these cells fulfill an important role for parasite persistence during chronic echinococcosis. KW - granulosus KW - hydatid disease KW - metacestode vesicles KW - antigen-B KW - alveoar echinococcosis KW - TGF-BETA KW - regulatory T cells KW - gene expression KW - Brugia Malayi KW - TNF-alpha Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134280 VL - 6 IS - 2 ER - TY - JOUR A1 - Götz, Ralph A1 - Panzer, Sabine A1 - Trinks, Nora A1 - Eilts, Janna A1 - Wagener, Johannes A1 - Turrà, David A1 - Di Pietro, Antonio A1 - Sauer, Markus A1 - Terpitz, Ulrich T1 - Expansion Microscopy for Cell Biology Analysis in Fungi JF - Frontiers in Microbiology N2 - Super-resolution microscopy has evolved as a powerful method for subdiffraction-resolution fluorescence imaging of cells and cellular organelles, but requires sophisticated and expensive installations. Expansion microscopy (ExM), which is based on the physical expansion of the cellular structure of interest, provides a cheap alternative to bypass the diffraction limit and enable super-resolution imaging on a conventional fluorescence microscope. While ExM has shown impressive results for the magnified visualization of proteins and RNAs in cells and tissues, it has not yet been applied in fungi, mainly due to their complex cell wall. Here we developed a method that enables reliable isotropic expansion of ascomycetes and basidiomycetes upon treatment with cell wall degrading enzymes. Confocal laser scanning microscopy (CLSM) and structured illumination microscopy (SIM) images of 4.5-fold expanded sporidia of Ustilago maydis expressing fluorescent fungal rhodopsins and hyphae of Fusarium oxysporum or Aspergillus fumigatus expressing either histone H1-mCherry together with Lifeact-sGFP or mRFP targeted to mitochondria, revealed details of subcellular structures with an estimated spatial resolution of around 30 nm. ExM is thus well suited for cell biology studies in fungi on conventional fluorescence microscopes. KW - Expansion microscopy KW - fluorescence microscopy KW - fungi KW - sporidia KW - hyphae Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202569 SN - 1664-302X VL - 11 ER - TY - JOUR A1 - Aldejohann, Alexander Maximilian A1 - Wiese-Posselt, Miriam A1 - Gastmeier, Petra A1 - Kurzai, Oliver T1 - Expert recommendations for prevention and management of Candida auris transmission JF - Mycoses N2 - Candida auris was first described as a yeast pathogen in 2009. Since then, the species has emerged worldwide. In contrast to most other Candida spp., C. auris frequently exhibits multi-drug resistance and is readily transmitted in hospital settings. While most detections so far are from colonised patients, C. auris does cause superficial and life-threatening invasive infections. During management of the first documented C. auris transmission in a German hospital, experts from the National Reference Centers for Invasive Fungal Infections (NRZMyk) and the National Reference Center for Surveillance of Nosocomial Infections screened available literature and integrated available knowledge on infection prevention and C. auris epidemiology and biology to enable optimal containment. Relevant recommendations developed during this process are summarised in this guidance document, intended to assist in management of C. auris transmission and potential outbreak situations. Rapid and effective measures to contain C. auris spread require a multi-disciplinary approach that includes clinical specialists of the affected unit, nursing staff, hospital hygiene, diagnostic microbiology, cleaning staff, hospital management and experts in diagnostic mycology / fungal infections. Action should be initiated in a step-wise process and relevant interventions differ between management of singular C. auris colonised / infected patients and detection of potential C. auris transmission or nosocomial outbreaks. KW - Candida auris KW - nosocomial transmission KW - infection prevention KW - expert recommendation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318570 VL - 65 IS - 6 SP - 590 EP - 598 ER - TY - JOUR A1 - Walther, Grit A1 - Zimmermann, Anna A1 - Theuersbacher, Johanna A1 - Kaerger, Kerstin A1 - Lilienfeld-Toal, Marie von A1 - Roth, Mathias A1 - Kampik, Daniel A1 - Geerling, Gerd A1 - Kurzai, Oliver T1 - Eye infections caused by filamentous fungi: spectrum and antifungal susceptibility of the prevailing agents in Germany JF - Journal of Fungi N2 - Fungal eye infections can lead to loss of vision and blindness. The disease is most prevalent in the tropics, although case numbers in moderate climates are increasing as well. This study aimed to determine the dominating filamentous fungi causing eye infections in Germany and their antifungal susceptibility profiles in order to improve treatment, including cases with unidentified pathogenic fungi. As such, we studied all filamentous fungi isolated from the eye or associated materials that were sent to the NRZMyk between 2014 and 2020. All strains were molecularly identified and antifungal susceptibility testing according to the EUCAST protocol was performed for common species. In total, 242 strains of 66 species were received. Fusarium was the dominating genus, followed by Aspergillus, Purpureocillium, Alternaria, and Scedosporium. The most prevalent species in eye samples were Fusarium petroliphilum, F. keratoplasticum, and F. solani of the Fusarium solani species complex. The spectrum of species comprises less susceptible taxa for amphotericin B, natamycin, and azoles, including voriconazole. Natamycin is effective for most species but not for Aspergillus flavus or Purpureocillium spp. Some strains of F. solani show MICs higher than 16 mg/L. Our data underline the importance of species identification for correct treatment. KW - eye infection KW - fungal infection KW - keratitis KW - antifungal susceptibility KW - natamycin KW - Fusarium KW - Purpureocillium KW - Aspergillus KW - Alternaria KW - Scedosporium Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241810 SN - 2309-608X VL - 7 IS - 7 ER - TY - JOUR A1 - Moremi, Nyambura A1 - Claus, Heike A1 - Vogel, Ulrich A1 - Mshana, Stephen E. T1 - Faecal carriage of CTX-M extended-spectrum beta-lactamase-producing Enterobacteriaceae among street children dwelling in Mwanza city, Tanzania JF - PLoS ONE N2 - Background Data on ESBL carriage of healthy people including children are scarce especially in developing countries. We analyzed the prevalence and genotypes of ESBL-producing Enterobacteriaceae (EPE) in Tanzanian street children with rare contact to healthcare facilities but significant interactions with the environment, animals and other people. Methodology/ Principle findings Between April and July 2015, stool samples of 107 street children, who live in urban Mwanza were analyzed for EPE. Intestinal carriage of EPE was found in 34 (31.8%, 95% CI; 22.7–40.3) children. Of the 36 isolates from 34 children, 30 (83.3%) were Escherichia coli (E. coli) and six Klebsiella pneumoniae (K. pneumoniae). Out of 36 isolates, 36 (100%), 35 (97%), 25 (69%) and 16 (44%) were resistant to tetracycline, trimethoprim-sulfamethoxazole, ciprofloxacin and gentamicin, respectively. Beta-lactamase genes and the multilocus sequence types of E. coli and K. pneumoniae were characterized. ESBL gene bla\(_{CTX-M-15}\) was detected in 75% (27/36) of ESBL isolates. Sequence types (STs) 131, 10, 448 and 617 were the most prevalent in E. coli. Use of local herbs (OR: 3.5, 95% CI: 1.51–8.08, P = 0.003) and spending day and night on streets (OR: 3.6, 95% CI: 1.44–8.97, P = 0.005) were independent predictors of ESBL carriage. Conclusions/ Significance We observed a high prevalence of bla\(_{CTX-M-15}\) in EPE collected from street children in Tanzania. Detection of E. coli STs 131, 10, 38 and 648, which have been observed worldwide in animals and people, highlights the need for multidisciplinary approaches to understand the epidemiology and drivers of antimicrobial resistance in low-income countries. KW - Tanzania KW - children KW - Enterobacteriaceae KW - ESBL Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170331 VL - 12 IS - 9 ER - TY - JOUR A1 - Soundararajan, Manonmani A1 - Marincola, Gabriella A1 - Liong, Olivia A1 - Marciniak, Tessa A1 - Wencker, Freya D. R. A1 - Hofmann, Franka A1 - Schollenbruch, Hannah A1 - Kobusch, Iris A1 - Linnemann, Sabrina A1 - Wolf, Silver A. A1 - Helal, Mustafa A1 - Semmler, Torsten A1 - Walther, Birgit A1 - Schoen, Christoph A1 - Nyasinga, Justin A1 - Revathi, Gunturu A1 - Boelhauve, Marc A1 - Ziebuhr, Wilma T1 - Farming practice influences antimicrobial resistance burden of non-aureus staphylococci in pig husbandries JF - Microorganisms N2 - Non-aureus staphylococci (NAS) are ubiquitous bacteria in livestock-associated environments where they may act as reservoirs of antimicrobial resistance (AMR) genes for pathogens such as Staphylococcus aureus. Here, we tested whether housing conditions in pig farms could influence the overall AMR-NAS burden. Two hundred and forty porcine commensal and environmental NAS isolates from three different farm types (conventional, alternative, and organic) were tested for phenotypic antimicrobial susceptibility and subjected to whole genome sequencing. Genomic data were analysed regarding species identity and AMR gene carriage. Seventeen different NAS species were identified across all farm types. In contrast to conventional farms, no AMR genes were detectable towards methicillin, aminoglycosides, and phenicols in organic farms. Additionally, AMR genes to macrolides and tetracycline were rare among NAS in organic farms, while such genes were common in conventional husbandries. No differences in AMR detection existed between farm types regarding fosfomycin, lincosamides, fusidic acid, and heavy metal resistance gene presence. The combined data show that husbandry conditions influence the occurrence of resistant and multidrug-resistant bacteria in livestock, suggesting that changing husbandry practices may be an appropriate means of limiting the spread of AMR bacteria on farms. KW - non-aureus staphylococci KW - NAS KW - alternative pig farming KW - antimicrobial resistance KW - one-health approach KW - intervention strategies KW - livestock-associated staphylococci KW - organic farming KW - pig farming methods Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312750 SN - 2076-2607 VL - 11 IS - 1 ER - TY - THES A1 - Schielke, Stephanie T1 - Functional and molecular characterization of FarR – a transcriptional regulator of the MarR family in Neisseria meningitidis T1 - Funktionelle und molekulare Charakterisierung von FarR, einem Transkriptionsregulator der MarR Familie in Neisseria meningitidis N2 - Neisseria meningitidis is a facultatively pathogenic human commensal and strictly adapted to its niche within the human host, the nasopharynx. Not much is known about the regulatory processes required for adaptation to this environment. Therefore the role of the transcriptional regulator NMB1843, one of the two predicted regulators of the MarR family in the meningococcal genome, was investigated. As this gene displayed a high sequence homology to FarR, the Fatty acid resistance Regulator in N. gonorrhoeae, we designated the meningococcal protein FarR (NmFarR). Homology modeling of this protein revealed a dimeric structure with the characteristic winged helix-turn-helix DNA binding motif of the MarR family. NmFarR is highly conserved among meningococcal strains and expression of farR during exponential growth is controlled post-transcriptionally, being highest in the late exponential phase. By means of electrophoretic mobility shift assays (EMSAs) the direct and specific binding of FarR to the farAB promoter region was shown, comparable to its homologue in gonococci. As FarR is involved in fatty acid resistance in N. gonorrhoeae, susceptibility assays with the medium chain lauric acid (C12:0), the long chain saturated palmitic acid (C16:0) and the long chain unsaturated linoleic acid (C18:2) were performed, testing a wide variety of strains of both species. In contrast to the unusually susceptible gonococci, a high intrinsic fatty acid resistance was detected in almost all meningococcal isolates. The molecular basis for this intrinsic resistance in N. meningitidis was elucidated, showing that both a functional FarAB efflux pump system as well as an intact lipopolysaccharide (LPS) are responsible for palmitic acid resistance. However, even despite circumvention of the intrinsic resistance, FarR could not be connected with fatty acid resistance in meningococci. Instead, FarR was shown to directly and specifically repress expression of the Neisseria adhesin A (nadA), a promising vaccine candidate absent in N. gonorrhoeae. Microarray analyses verified these results and disclosed no further similarly regulated genes, rendering the FarR regulon the smallest regulon in meningococci reported until now. The exact FarR binding site within the nadA promoter region was identified as a 16 bp palindromic repeat and its influence on nadA transcription was proved by reporter gene fusion assays. This repression was also shown to be relevant for infection as farR deficient mutant strains displayed an increased attachment to epithelial cells. Furthermore, farR transcription was attested to be repressed upon contact with active complement components within human serum. Concluding, it is shown that FarR adopted a role in meningococcal host niche adaptation, holding the balance between immune evasion by repressing the highly antigenic nadA and host cell attachment via this same adhesin. N2 - Neisseria meningitidis ist ein fakultativ pathogener menschlicher Kommensale und eng an die Bedingungen seiner spezifischen Nische, den Nasopharynx, angepasst. Über die regulatorischen Mechanismen, die für diese Anpassung vonnöten sind, ist nicht viel bekannt. Daher wurde die Rolle des Transkriptionsregulators NMB1843 untersucht, eines der beiden prognostizierten Regulatoren der MarR Familie im Meningokokken-Genom. Aufgrund einer hohen Sequenzhomologie dieses Gens zu FarR, dem Fatty acid resistance Regulator in N. gonorrhoeae, nannten wir das Meningokokken-Protein ebenfalls FarR (NmFarR). Homologie-Modellierung dieses Proteins ergab eine dimere Struktur mit dem charakteristischen winged helix-turn-helix DNA-Bindemotiv der MarR Familie. Es wurde gezeigt, dass NmFarR in Meningokokken-Stämmen hochkonserviert ist. Die Expression von farR wird während des exponentiellen Wachstums posttranskriptional kontrolliert und erreicht ihren Höchststand in der spätexponentiellen Phase. Wie bei seinem Homolog in Gonokokken konnte die direkte und spezifische Bindung von FarR an die farAB Promotorregion nachgewiesen werden. Da FarR in N. gonorrhoeae an der Fettsäureresistenz beteiligt ist, wurde die Suszeptibilität einer großen Auswahl von Stämmen beider Spezies gegenüber drei unterschiedlichen Fettsäuren getestet: Laurinsäure (C12:0), Palmitinsäure (C16:0) und Linolsäure (C18:2). Im Gegensatz zu den ungewöhnlich sensitiven Gonokokken konnte eine hohe inhärente Fettsäureresistenz in fast allen Meningokokken-Isolaten beobachtet werden. Nach Analyse der molekularen Grundlage dieser Resistenz konnte gezeigt werden, dass sowohl eine funktionale FarAB Efflux-Pumpe als auch ein intaktes Lipopolysaccharid (LPS) für die Palmitinsäureresistenz verantwortlich sind. Trotz Umgehung der inhärenten Resistenz konnte keine Verbindung von FarR mit Fettsäureresistenz in Meningokokken hergestellt werden. Stattdessen reprimiert FarR direkt und spezifisch die Expression des Neisseria Adhäsins A (nadA), eines vielversprechenden Impfstoffbestandteils. Microarrays bestätigten diese Ergebnisse, zeigten aber keine weiteren ähnlich regulierten Gene auf. Somit ist das FarR-Regulon das bisher kleinste Regulon in Meningokokken. Die genaue FarR-Bindestelle innerhalb des nadA Promotors wurde als ein 16 bp Palindrom identifiziert und dessen Einfluss auf die Transkription von nadA mittels Reportergenanalysen gezeigt. Auch in Infektionsversuchen wurde die Relevanz dieser Repression deutlich, da ein farR-deletierter Stamm eine höhere Adhärenz an Epithelzellen aufwies. Die Transkription von farR sank nach Kontakt mit aktiven Komplementbestandteilen aus humanem Serum. Zusammenfassend wurde gezeigt, dass FarR eine Rolle in der Nischenadaptation von Meningokokken zukommt, indem er zwischen Immunevasion durch Repression des hoch-immunogenen nadA und Wirtszelladhäsion durch eben dieses Adhäsin vermittelt. KW - Transkription KW - Neisseria gonorrhoeae KW - Neisseria meningitidis KW - Adhäsine KW - FarR KW - Transkriptionsregulation KW - NadA KW - Neisseria meningitdis KW - transcriptional regulation KW - FarR KW - Neisseria gonorrhoeae KW - niche adaptation Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48550 ER - TY - THES A1 - Spatz, Carolin Julia Angelika T1 - Funktion des Transkriptionsregulators FarR in Neisseria meningitidis T1 - Function of the transcriptional regulator FarR in Neisseria meningitidis N2 - Neisseria meningitidis, Auslöser der Meningokokken-Meningitis und Sepsis, trägt auch heute noch zur hohen Kindersterblichkeit in Entwicklungsländern bei und sorgt, vor allem im afrikanischen Meningitis-Gürtel, immer wieder für Epidemien mit gravierenden Folgen für die Betroffenen. Im Rahmen dieser Arbeit wurden zwei an der Pathogenität von N. meningitidis beteiligte Proteine, der Transkriptionsregulator FarR und der Transportkanal HrpB, näher charakterisiert, um weitere Einblicke in die immer noch nicht vollständig entschlüsselte Pathogenese der Meningokokken-Meningitis zu erhalten. Das Neisseria adhesin A NadA ist Bestandteil der sich aktuell in der Entwicklung befindenden Impfung gegen Meningokokken der Serogruppe B. Im dem bekapselten B-Stamm MC58 wurde gezeigt, dass nadA unter der negativen Kontrolle des Transkriptionsregulators FarR steht (Schielke et al., 2009). In den ebenfalls zur Gattung Neisseria gehörenden Neisseria gonorrhoeae (Ng) wurde bereits 2001 ein FarR-Homolog beschrieben (Shafer et al., 2001). NgFarR ist an der Resistenz gegenüber antimikrobiellen, langkettigen Fettsäuren beteiligt, indem es die Expression des FarABEffluxpumpen-Systems reguliert, welches eingedrungene Fettsäuren wieder nach extrazellulär befördert. Dagegen zeigten Palmitinsäure-Resistenztests, dass FarR nicht an der intrinsischen Fettsäure-Resistenz der Meningokokken beteiligt ist. Die Deletion und die Komplementierung von farR hatten weder in bekapselten noch in unbekapselten Meningokokken Einfluss auf das normale Wachstumsverhalten. Ein Western Blot- Nachweis des FarR-Proteins in der frühen, mittleren und späten exponentiellen Wachstumsphase von Wildtyp, Kapsel-Deletionsmutante und farR-Komplementante zeigte, dass die Menge an FarR im zeitlichen Verlauf kontinuierlich zunimmt und FarR damit Wachstumsphasen-abhängig exprimiert wird. Dabei scheint es einer posttranskriptionalen oder posttranslationalen Regulation zu unterliegen, da auch in dem farRkomplementierten Stamm unabhängig vom farR-Promotor eine entsprechende Hochregulation stattfindet. In Infektionsversuchen wurde die Interaktion zwischen Meningokokken und humanen polymorphkernigen Granulozyten untersucht. In den Infektionsassays wurde die farRDeletionsmutante innerhalb des dreistündigen Versuchsrahmens deutlich stärker durch die Granulozyten abgetötet als der Serogruppe B-Wildtyp. Als Mitglied der in Bakterien und Archaeen weit verbreiteten Familie der MarR-Transkriptionsregulatoren (Multiple antibiotic resistance Regulator, MarR) bindet FarR mit hoher Wahrscheinlichkeit auch als Homodimer an seine Bindesequenz auf der DNA. FarR erkennt eine 16 bp lange, palindromische Sequenz in der Promotorregion von nadA (NMB1994), wodurch die nadA-Expression verhindert wird. Außerdem erkennt FarR eine ähnliche Bindesequenz im Promotorbereich von farAB (NMB0318/0319), wobei es aber keinen regulatorischen Einfluss ausübt. Mit einer aus diesen beiden Bindestellen berechneten minimalen Bindesequenz wurde im Genom von MC58 weitere mögliche Bindepartner detektiert. Eine Auswahl dieser möglichen Bindestellen wurde in Electrophoretic Mobility Shift Assays auf eine direkte Interaktion mit dem FarR-Protein hin untersucht, wobei sich allerdings keine direkte Bindung nachweisen ließ. Diese Ergebnisse darauf hin, dass der Transkriptionsregulator FarR hoch spezifisch bestimmte DNA-Bindesequenzen erkennt und die entsprechenden Gene reguliert. In der Promotorregion des TpsB-Proteins HrpB wurde in den sequenzierten Referenzstämmen Z2491, MC58, FAM18 und α14 eine mit der minimalen FarR-Bindesequenz kompatible Sequenz gefunden. In Electrophoretic Mobility Shift Assays konnte allerdings gezeigt werden, dass FarR nicht direkt daran bindet. Um das Transport-Protein HrpB näher zu charakterisieren, wurde das entsprechende Gen in 22 N. meningitidis-Isolaten sequenziert. Dabei zeigte sich, dass das Transportprotein hrpB in allen untersuchten invasiven und nicht-invasiven Stämmen vorhanden ist. Dieses äußerst konservierte Protein weist nur im seinem C-terminalen Bereich eine relativ variable Region auf, was vermutlich auf Rekombinationsereignisse zurückzuführen ist. Ein Alignment der Aminosäure-Sequenz des Serogruppe C-Stamms FAM18 mit der des homologen Bordetella pertussis TpsB-Proteins FhaC zeigte, dass die dreidimensionale Struktur des HrpB ebenfalls eine α-Helix, eine transmembranöse Domäne und variable extrazelluläre Loops enthält. Zusammengenommen erfüllt HrpB somit wichtige Bedingungen, um als Vakzine-Bestandteil in Betracht gezogen zu werden. N2 - Function of the transcriptional regulator FarR in Neisseria meningitidis KW - Transkriptionsregulator KW - Neisseria meningitidis KW - HrpB KW - hemolysin related protein B KW - Zwei-Partner-Sekretions-Systeme KW - FarR KW - fatty acid resistence KW - Transkriptional regulator KW - Neisseria meningitidis KW - HrpB KW - hemolysin related protein B KW - Two-Partner-secretion-system KW - FarR Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-73740 ER - TY - THES A1 - Pawlik, Marie-Christin T1 - Gene expression in the human pathogen Neisseria meningitidis: Adaptation to serum exposure and zinc limitation T1 - Genexpression im humanen Pathogen Neisseria meningitidis: Adaptation an Serumexposition und Zinkmangel N2 - Neisseria meningitidis is a facultative human pathogen that occasionally shows strong resistance against serum complement exposure. Previously described factors that mediate meningococcal serum resistance are for example the capsule, LPS sialylation, and expression of the factor H binding protein. I aimed for identification of novel serum resistance factors, thereby following two approaches, i) the analysis of the impact of global regulators of gene expression on serum resistance; and ii) a comparative analysis of closely related strains differing in serum resistance. (i) Of six meningococcal global regulators of gene expression studied, only mutation of the zinc uptake regulator Zur reduced complement deposition on meningococci. Little was known about meningococcal Zur and regulatory processes in response to zinc. I therefore elucidated the yet unidentified meningococcal Zur regulon comparing the transcriptional response of the N. meningitidis strain MC58 under zinc-rich and zinc-deficient conditions using a common reference design of microarray analysis. The meningococcal Zur regulon comprises 17 genes, of which 15 genes were repressed and two genes were activated at high zinc condition. Amongst the Zur-repressed genes were genes involved in zinc uptake, tRNA modification, and ribosomal assembly. A 23 bp meningococcal consensus Zur binding motif (Zur box) with a conserved central palindrome was established (TGTTATDNHATAACA) and detected in the promoter region of all regulated transcriptional units (genes/operons). In vitro binding of meningococcal Zur to the Zur box of three selected genes was shown for the first time using EMSAs. Binding of meningococcal Zur to DNA depended specifically on zinc, and mutations in the palindromic sequence constrained Zur binding to the DNA motif. ii) Three closely related strains of ST-41/44 cc from invasive disease and carriage which differed in their resistance to serum complement exposure were analysed to identify novel mediators of serum resistance. I compared the strains’ gene content by microarray analysis which revealed six genes being present in both carrier isolates, but absent in the invasive isolate. Four of them are part of two Islands of horizontally transferred DNA, i.e. IHT-B and –C. The working group furthermore applied a comprehensive screening assay, a transcriptome and a proteome analysis leading to identification of three target proteins. I contributed to establish the role of these three proteins in serum resistance: The adhesin Opc mediates serum resistance by binding of vitronectin, a negative regulator of the complement system; the hypothetical protein NMB0865 slightly contributes to serum resistance by a yet unknown mechanism; and NspA, recently identified to bind the negative complement regulator factor H, led to considerable reduced complement-mediated killing. N2 - Neisseria meningitidis ist ein fakultatives Humanpathogen, welches mitunter sehr resistant gegenüber Serumkomplement-Exposition ist. Bereits beschriebene Faktoren, welche die Serumresistenz von Meningokokken fördern, sind beispielsweise die Kapsel, LPS-Sialylierung und Expression des fH-bindenden Proteins. Das Ziel dieser Arbeit war die Identifikation neuartiger Serumresistenzfaktoren, wobei ich zwei Ansätzen verfolgte: i) Die Analyse des Einflusses von globalen Regulatoren der Genexpression auf die Serumresistenz; und ii) eine vergleichenden Analyse von eng verwandten Stämmen, die sich hinsichtlich ihrer Serumresistanz unterschieden. i) Von sechs untersuchten globalen Regulatoren der Genexpression, war die Komplementdeposition auf Meningokokken nur nach Mutation des Regulators der Zinkaufnahme, Zur, reduziert. Über Zur selbst und die regulatorischen Prozesse in Reaktion auf Zink war in Meningokokken wenig bekannt. Ich habe daher das bisher nicht bestimmte Zur-Regulon von Meningokokken aufgeklärt, wofür ich mittels Mikroarrays die transkriptionelle Antwort des N. meningitidis-Stammes MC58 unter Zink-Überfluss und Zink-Mangel zu vergleichen. Das Zur-Regulon von Meningokokken umfasst 17 Gene, von denen unter Zinküberfluss 15 reprimiert und zwei aktiviert wurden. Unter den Zur-reprimierten Genen fanden sich Gene, die in die Aufnahme von Zink, die Modikation von tRNAs und den Zusammenbau des Ribosoms involviert sind. Ein 23 bp langes Binde-Konsensusmotiv für Meningokokken-Zur (Zur-Box) mit einem konservierten zentralen Palindrom wurde ermittelt (TGTTATDNHATAACA) und in der Promotorregion aller regulierten Transkriptionseinheiten (Gene/Operons) detektiert. In vitro-Bindung des N. meningitidis Zur an die Zur-Box dreier ausgewählter Genen konnte mittels EMSAs erstmals gezeigt werden. Die Bindung von Zur an DNA war spezifisch abhängig von Zink, und Mutationen in der palindromischen Sequenz hemmten die Zur-Bindung an das DNA-Motiv. ii) Drei eng verwandte Stämme des ST-41/44-Komplexes aus invasiver Erkrankung und Trägertum, die sich in ihrer Resistenz gegenüber Serumkomplement-Exposition unterschieden, wurden analysiert um neuartige Mediatoren der Serumresistenz zu identifizieren. Der Gengehalt der Stämme wurde mittels Mikroarray-Analyse verglichen. Dies offenbarte sechs Gene, die in den beiden Trägerstämmen vorhanden, aber in dem invasiven Isolat abwesend waren. Vier dieser Gene liegen innerhalb zweier Inseln horizontal transferierter DNA, d.h. IHT-B und –C. Weiterhin führte die Arbeitsgruppe eine Transkriptom- und Proteom-Analyse der drei Stämme sowie einen umfangsreichen Screening-Assay durch. Diese Ansätze führten zur Identifikation dreier Kandidaten-Proteine für die weitere Analyse. Ich wirkte daran mit, die Rolle dieser Proteine für die Serumresistenz von Meningokokken zu ermitteln: Das Adhäsin Opc vermittelt Serumresistenz durch Bindung von Vitronektin, einem negativen Regulator des Komplementsystems; das hypothetische Protein NMB0865 trägt über einen bisher unbekannten Mechanismus geringfügig zur Serumresistanz bei; und NspA, für welches vor Kurzem erkannt wurde, dass es den negativen Komplementregulator Faktor H bindet, führte zu beträchtlich reduzierter Abtötung durch Komplement. KW - Komplement KW - Neisseria meningitidis KW - Genregulation KW - Zinkmangel KW - Serumresistenz KW - Meningokokken KW - globale Regulatoren KW - Serum KW - Bakterien KW - Zink KW - serum resistance KW - meningococci KW - global regulators KW - zinc limitation Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78758 ER - TY - THES A1 - Oberkötter, Marc T1 - Genetische Diversität der humanen kommensalen Bakterienart Neisseria lactamica in epidemiologisch verknüpften Gruppen T1 - Genetic Diversity of Neisseria lactamica Strains form Epidemiologically Defined Carriers N2 - Im Rahmen der von November 1999 bis März 2000 durchgeführten bayerischen Meningokokkenträgerstudie wurden in zahlreichen Kindergärten und Schulen der bayerischen Gemeinden Ansbach, Augsburg, Erlangen, Griesbach, Ingolstadt, München, Pfarrkirchen, Sonthofen und Weiden insgesamt 287 Neisseria lactamica-Stämme isoliert. 26 ausgewählte, aus den benachbarten Städten Augsburg, Ingolstadt und München stammende Isolate wurden einer Multi-Lokus-Sequenztypisierung (MLST) zur Untersuchung ihrer genetischen Diversität unterzogen. Dabei wurden sowohl Sequenzen der 3 Stoffwechselgene argF, recA und rho, als auch Sequenzen des 16S rRNA-Gens analysiert. Für das 16S rRNA-Gen fanden sich zehn, für argF fünf, für recA acht und für rho neun differente Allele. Auf Basis der vier analysierten Gene konnten 17 verschiedene Genotypen definiert werden, von denen zwölf nur einmal, fünf hingegen mehrmals vorkamen. Es ist anzunehmen, dass durch Sequenzierung der vier in dieser Studie verwendeten Gene bereits eine ausreichende Diskriminierung von Neisseria lactamica erfolgte, da Versuche eine weiterführende Diskriminierung durch Sequenzierung des porB-Gens zu erreichen, keine wesentlichen zusätzlichen Informationen erbrachten. Durch visuelle Inspektion der Sequenzen konnte bei allen vier Genloci das Überwiegen von Rekombinationsereignissen gegenüber Punktmutationen bestätigt werden, so dass für die Spezies Neisseria lactamica horizontaler Gentransfer anzunehmen ist. Da nur ein einziger Genotyp in zwei verschiedenen Städten beobachtet wurde, zeigen die Ergebnisse der vorliegenden Arbeit, dass eine klonale Ausbreitung von Neisseria lactamica nur dann nachweisbar ist, wenn eine epidemiologische Verknüpfung zwischen Trägern besteht. N2 - We assessed the genetic diversity of 26 Neisseria lactamica strains from epidemiologically related sources, i.e., groups of kindergartens and primary schools in three Bavarian towns, by the partial sequencing of the argF, rho, recA, and 16S ribosomal genes. We found a total of 17 genotypes, of which 12 were found only in one strain. The genotypes comprised 5 alleles of the argF gene, 9 of rho, 8 of recA, and 10 of the 16S ribosomal DNA. Sequence analysis by determination of homoplasy ratios and split decomposition analysis revealed abundant recombination within N. lactamica. KW - Neisseria lactamica KW - Neisseria meningitidis KW - Populationsstruktur KW - Homoplasie Testung KW - Split Decomposition Analyse KW - Neisseria lactamica KW - Neisseria meningitidis KW - Homoplasy Ratio KW - Split Decompostion Analysis Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-10142 ER - TY - THES A1 - Hauer [geb. Lein], Nina T1 - Genetische Variabilität und Expression der ADP-Ribosyltransferase NarE T1 - Genetic variability and expression of ADP-ribosyltransferase NarE N2 - Neisseria meningitidis ist Auslöser invasiver Infektionen, die Sepsis und Meningitis hervorrufen. Bakterielle ADP-Ribosyltransferasen wurden als Toxine zahlreicher Bakterien wie E.coli, V. cholerae und B. pertussis beschrieben, die postranslationale Modifikationen bei eukaryotischen Proteinen mit pathologischer Wirkung für den Menschen hervorrufen. Die ADP-Ribosyltransferase NarE von Neisserien ist auf der Basis von Sequenzhomologien identifiziert worden. Die enzymatische Aktivität des Proteins wurde bereits in Studien gezeigt. Ziel dieser Arbeit war, NarE aus epidemiologischem und populationsbiologischem Blickwinkel zu betrachten. Insgesamt wurden 576 Meningokokkenisolate (109 Isolate aus der Stammsammlung des Instituts für Hygiene und Mikrobiologie Würzburg und 467 Isolate der Meningococcus Genome Library der Meningitis Research Foundation) auf das Vorhandensein von narE sowie auf Sequenzvariationen untersucht. Das Ergebnis zeigte den Besitz des Gens bei insgesamt 247 Stämmen. Bis auf zwei Punktmutationen waren alle untersuchten narE-Sequenzen identisch. Die narE-positiven Isolate konnten neun klonalen Komplexen zugeordnet werden. Zusätzlich wurde veranschaulicht, dass das Gen in Komplexen vorkommt, die verwandtschaftlich nicht eng miteinander verbunden sind. Mittels Western Blot konnte bei allen narE-positiven Meningokokken die Proteinexpression bestätigt werden, wobei ein signifikanter Unterschied zwischen Stämmen des cc32 und cc41/44 festzustellen war. Auf Transkriptionsebene konnte mittels qRT-PCR kein Unterschied zwischen diesen Komplexen ermittelt werden, so dass der Expressionsunterschied auf einem posttranskriptionellen Mechanismus beruhen muss. Neisseria gonorrhoeae ist ebenfalls im Besitz des Gens wie von Masignani et al. (2003) am Beispiel weniger Isolate beschrieben. In dieser Arbeit konnte für alle 29 getesteten Gonokokken die Insertion von vier Basenpaaren bestätigt werden, die zu einer Verschiebung im Leseraster führt, so dass NarE nicht exprimiert wird. Auch ein Neisseria sicca Stamm beinhaltet und exprimiert das narE-Gen. N2 - Bacterial ADP-ribosyltransferases have been described as toxins of numerous bacteria such as E. coli, V. cholerae and B. pertussis that cause posttranslational modifications of eukaryotic proteins with pathological effects in humans. The ADP-ribosyltransferase NarE from Neisseria has been identified on the basis of sequence homologies. The enzymatic activity of the protein has already been shown in studies. The aim of this work was to look at NarE from an epidemiological and population biological point of view. A total of 576 meningococcal isolates were investigated for the presence of narE and for sequence variations. The result showed the possession of the gene in a total of 247 strains. With the exception of two point mutations, all investigated narE sequences were identical. The narE-positive isolates could be assigned to nine clonal complexes. In addition, it was demonstrated that the gene occurs in complexes that are not closely related. Western blot confirmed protein expression in all narE-positive meningococci with a significant difference between cc32 and cc41/44 strains. At the transcriptional level, qRT-PCR could not detect any difference between these complexes, so that the expression difference must be based on a post-transcriptional mechanism. Neisseria gonorrhoeae is also in possession of the gene as described by Masignani et al. (2003) using the example of a few isolates. In this work, the insertion of four base pairs was confirmed for all 29 gonococci tested, which leads to a shift in the reading frame so that NarE is not expressed. A Neisseria sicca strain also contains and expresses the narE gene. KW - Neisseria meningitidis KW - ADP-Ribosyltransferasen KW - NarE KW - Virulenzfaktor KW - Meningokokken Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187803 ER - TY - THES A1 - Herz, Michaela T1 - Genome wide expression profiling of Echinococcus multilocularis T1 - Genomweite Expressionsanalysen von Echinococcus multilocularis N2 - Alveolar echinococcosis, which is caused by the metacestode stage of the small fox tapeworm Echinococcus multilocularis, is a severe zoonotic disease with limited treatment options. For a better understanding of cestode biology the genome of E. multilocularis, together with other cestode genomes, was sequenced previously. While a few studies were undertaken to explore the E. multilocularis transcriptome, a comprehensive exploration of global transcription profiles throughout life cycle stages is lacking. This work represents the so far most comprehensive analysis of the E. multilocularis transcriptome. Using RNA-Seq information from different life cycle stages and experimental conditions in three biological replicates, transcriptional differences were qualitatively and quantitatively explored. The analyzed datasets are based on samples of metacestodes cultivated under aerobic and anaerobic conditions as well as metacestodes obtained directly from infected jirds. Other samples are stem cell cultures at three different time points of development as well as non-activated and activated protoscoleces, the larval stage that can develop into adult worms. In addition, two datasets of metacestodes under experimental conditions suitable for the detection of genes that are expressed in stem cells, the so-called germinative cells, and one dataset from a siRNA experiment were analyzed. Analysis of these datasets led to expression profiles for all annotated genes, including genes that are expressed in the tegument of metacestodes and play a role in host-parasite interactions and modulation of the host's immune response. Gene expression profiles provide also further information about genes that might be responsible for the infiltrative growth of the parasite in the liver. Furthermore, germinative cell-specific genes were identified. Germinative cells are the only proliferating cells in E. multilocularis and therefore of utmost importance for the development and growth of the parasite. Using a combination of germinative cell depletion and enrichment methods, genes with specific expression in germinative cells were identified. As expected, many of these genes are involved in translation, cell cycle regulation or DNA replication and repair. Also identified were transcription factors, many of which are involved in cell fate commitment. As an example, the gene encoding the telomerase reverse transcriptase (TERT) was studied further. Expression of E. multilocularis tert in germinative cells was confirmed experimentally. Cell culture experiments indicate that TERT is required for proliferation and development of the parasite, which makes TERT a potentially interesting drug target for chemotherapy of alveolar echinococcosis. Germinative cell specific genes in E. multilocularis also include genes of densoviral origin. More than 20 individual densovirus loci with information for non-structural and structural densovirus proteins were identified in the E. multilocularis genome. Densoviral elements were also detected in many other cestode genomes. Genomic integration of these elements suggests that densovirus-based vectors might be suitable tools for genetic manipulation of tapeworms. Interestingly, only three of more than 20 densovirus loci in the E. multilocularis genome are expressed. Since the canonical piRNA pathway is lacking in cestodes, this raises the question about potential silencing mechanisms. Exploration of RNA-Seq information indicated natural antisense transcripts as a potential gene regulation mechanism in E. multilocularis. Preliminary experiments further suggest DNA-methylation, which was previously shown to occur in platyhelminthes, as an interesting avenue to explore in future. The transcriptome datasets also contain information about genes that are expressed in differentiated cells, for example the serotonin transporter gene that is expressed in nerve cells. Cell culture experiments indicate that serotonin and serotonin transport play an important role in E. multilocularis proliferation, development and survival. Overall, this work provides a comprehensive transcription data atlas throughout the E. multilocularis life cycle. Identification of germinative cell-specific genes and genes important for host-parasite interactions will greatly facilitate future research. A global overview of gene expression profiles will also aide in the detection of suitable drug targets and the development of new chemotherapeutics against alveolar echinococcosis. N2 - Alveoläre Echinokokkose wird durch das Metazestodenstadium des kleinen Fuchsbandwurms Echinococcus multilocularis verursacht und medizinisch als eine schwere Zoonose mit begrenzten Behandlungsmöglichkeiten betrachtet. Um ein besseres Verständnis für die Biologie der Zestoden zu erlangen, wurde das Genom von E. multilocularis, zusammen mit denen anderer Zestoden, bereits sequenziert. Bisher wurden nur wenige Studien zum Transkriptom von E. multilocularis durchgeführt und eine umfassende Analyse der Transkriptionsprofile über verschiedene Stadien des Lebenszyklus hinweg fehlt bislang. Diese Arbeit stellt die bisher umfassendste Untersuchung des Transkriptoms von E. multilocularis dar. Unterschiede in der Genexpression in verschiedenen Stadien des Lebenszyklus und unter experimentellen Bedingungen wurden qualitativ und quantitativ untersucht. Dazu wurden Daten aus RNA-Sequenzierungen in drei biologischen Replikaten verwendet. Die untersuchten Datensätze beruhen auf Proben von Metazestoden, die unter aeroben und anaeroben Bedingungen kultiviert, sowie von Metazestoden, die direkt aus Gerbilen isoliert wurden. Weitere Proben umfassen Stammzellkulturen zu drei verschiedenen Entwicklungszeitpunkten sowie nicht-aktivierte und aktivierte Protoskolizes, das Larvenstadium das sich zu Adulten entwickeln kann. Zusätzlich wurden zwei Datensätze von Metazestoden unter experimentellen Bedingungen, die zur Identifizierung stammzellspezifischer (keimzellspezifischer) Gene geeignet sind, sowie ein Datensatz von einem siRNA-Experiment untersucht. Die Analyse dieser Datensätze führte zu Genexpressionsprofilen für alle annotierten Gene, unter anderem für Gene, die im Tegument des Metazestoden exprimiert werden und eine Rolle spielen bei Wirt-Parasit-Interaktionen und der Modulierung der Immunantwort des Wirts. Genexpressionsprofile liefern zudem Informationen über Gene, die für das infiltrative Wachstum des Parasiten in der Leber verantwortlich sein könnten. Des Weiteren wurden keimzellspezifische Gene identifiziert. Keimzellen sind die einzigen proliferierenden Zellen in E. multilocularis und daher von essentieller Bedeutung für die Entwicklung und das Wachstum des Parasiten. Durch eine Kombination von Keimzelldepletierungs- und Keimzellanreicherungsverfahren wurden Gene mit keimzellspezifischer Expression identifiziert. Wie erwartet, sind viele dieser Gene in der Translation, der Zellzyklusregulation oder DNA-Replikation und –Reparatur involviert. Darüber hinaus wurden keimzellspezifisch exprimierte Transkriptionsfaktoren detektiert, von denen viele in der Festlegung des Zellschicksals eine Rolle spielen. Als Beispiel eines keimzellspezifischen Genes wurde das Gen, das für die reverse Transkriptase (TERT) kodiert, genauer untersucht. Die Expression von E. multilocularis tert in Keimzellen wurde experimentell bestätigt. Zellkulturexperimente weisen darauf hin, dass TERT für die Proliferation und die Entwicklung essentiell ist. TERT ist daher ein potentiell interessantes Wirkstofftarget für die chemotherapeutische Behandlung der alveolären Echinokokkose. Zu den keimzellspezifischen Genen in E. multilocularis gehören auch Gene densoviralen Ursprungs. Es wurden mehr als 20 Densovirusloci mit Informationen für nicht-strukturelle und strukturelle Densovirusproteine im E. multilocularis-Genom identifiziert. Densovirale Elemente wurden auch in vielen anderen Zestodengenomen detektiert. Die genomische Integration dieser Elemente deutet darauf hin, dass densovirus-basierte Vektoren zur genetischen Manipulation von Zestoden geeignet sein könnten. Interessanterweise sind nur drei von mehr als 20 Densovirusloci im E. multilocularis-Genom exprimiert. Da es in Zestoden keinen kanonischen piRNA-Signalweg gibt, stellt sich die Frage nach möglichen Genabschaltungsmechanismen. Die Analyse der RNA-Sequenzierdaten ergab Hinweise auf natürliche Antisense-Transkripte als einen möglichen Genregulationsmechanismus in E. multilocularis. Vorläufige Experimente und bisherige Studien deuten weiterhin darauf hin, dass DNA-Methylierung ein Mechanismus der Genregulation und -abschaltung in Zestoden sein könnte. Die Transkriptionsdaten enthalten auch Informationen zu Genen, die in differenzierten Zellen exprimiert werden, wie zum Beispiel das Serotonintransportergen, das in Nervenzellen exprimiert wird. Zellkulturversuche weisen darauf hin, dass Serotonin und Serotonintransport eine wichtige Rolle bei der Proliferation, der Entwicklung und dem überleben von E. multilocularis spielen. Insgesamt bietet diese Arbeit einen umfassenden Transkriptionsdatenatlas über die Stadien des Lebenszyklus von E. multilocularis. Die Identifizierung von keimzellspezifischen Genen und Genen, die für die Interaktion zwischen Wirt und Parasit wichtig sind, wird die zukünftige Forschung erheblich erleichtern. Ein globaler Überblick über die Genexpressionsprofile wird zudem hilfreich sein bei der Entdeckung geeigneter Wirkstofftargets und bei der Entwicklung neuer Chemotherapeutika gegen die alveoläre Echinokokkose. KW - Fuchsbandwurm KW - Serotonin KW - Telomerase KW - Stammzelle KW - Transkriptomanalyse KW - foxtapeworm KW - transcriptome data analysis KW - germinative cell Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203802 ER - TY - THES A1 - Weinand, Hanne T1 - Herstellung eines monoklonalen Antikörpers gegen die Endonuklease NmeDI zur Typisierung von Neisseria meningitidis T1 - Development of monoclonal antibodies directed against the endonuclease NmeDI for typing of Neisseria meningitidis N2 - Neisseria meningitidis ist eine der führenden Ursachen von Morbidität und Mortalität sowohl bei Kindern als auch bei Erwachsenen. Die Typisierung ist die Grundlage für die epidemiologische Überwachung der Erkrankung durch Meningokokken. Die Endonuklease NmeDI ist spezifisch für die klonalen Linien des ST-8 und ST-11 Komplex Meninkokken, die mit Erkrankungen der Serogruppe C assoziiert sind. Deshalb wurde für die rasche Identifizierung von Stämmen dieser Linien ein monoklonaler Antikörper entwickelt. Der Antikörper erkennt spezifisch die ST-8 und ST-11 Komplex Meningokokken in Western-Blot und Dot-Blot. Er wird mitlerweile routinemäßig im Nationalen Referenzzentrum für Meningokokken zur Identifizierung der Linien ohne zusätzliche Anwendung der Multilokus Sequenz Typisierung (MLST) eingesetzt. N2 - Neisseria meningitidis is a leading cause of morbidity and mortality in children and adolescents. Typing is essential for epidemiological surveillance of meningococcal disease. The endonuclease NmeDI is specific to the clonal lineages ST-8 and ST-11 complex associated with serogroup C disease. Therefore, a monoclonal antibody was developed for rapid identification of strains belonging to these lineages. The antibody specifically recognized ST-8 and ST-11 complex meningococci in Western blots and dot blots. It is now routinely used at the German National reference centre for meningococci for presumptive identification of the lineages without multilocus sequence typing. KW - Herzmuskel KW - Durchblutungsmessung KW - NMR-Tomographie KW - Neisseria meningitidis KW - monoklonale Antikörper KW - NmeDI KW - Typisierung KW - Neisseria meningitidis KW - monoclonal antibodies KW - NmeDI KW - typing Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-12878 ER - TY - JOUR A1 - Nyawale, Helmut A. A1 - Moremi, Nyambura A1 - Mohamed, Mohamed A1 - Njwalila, Johnson A1 - Silago, Vitus A1 - Krone, Manuel A1 - Konje, Eveline T. A1 - Mirambo, Mariam M. A1 - Mshana, Stephen E. T1 - High seroprevalence of SARS-CoV-2 in Mwanza, northwestern Tanzania: a population-based survey JF - International Journal of Environmental Research and Public Health N2 - The transmission of the SARS-CoV-2 virus, which causes COVID-19, has been documented worldwide. However, the evidence of the extent to which transmission has occurred in different countries is still to be established. Understanding the magnitude and distribution of SARS-CoV-2 through seroprevalence studies is important in designing control and preventive strategies in communities. This study investigated the seropositivity of the SARS-CoV-2 virus antibodies in the communities of three different districts in the Mwanza region, Tanzania. A household cross-sectional survey was conducted in September 2021 using the modified African Centre for Disease and Prevention (ACDC) survey protocol. A blood sample was obtained from one member of each of the selected households who consented to take part in the survey. Immunochromatographic rapid test kits were used to detect IgM and IgG SARS-CoV-2 antibodies, followed by descriptive data analysis. Overall, 805 participants were enrolled in the study with a median age of 35 (interquartile range (IQR):27–47) years. The overall SARS-CoV-2 seropositivity was 50.4% (95%CI: 46.9–53.8%). The IgG and IgM seropositivity of the SARS-CoV-2 antibodies was 49.3% and 7.2%, respectively, with 6.1% being both IgG and IgM seropositive. A history of runny nose (aOR: 1.84, 95%CI: 1.03–3.5, p = 0.036), loss of taste (aOR: 1.84, 95%CI: 1.12–4.48, p = 0.023), and living in Ukerewe (aOR: 3.55, 95%CI: 1.68–7.47, p = 0.001) and Magu (aOR: 2.89, 95%CI: 1.34–6.25, p= 0.007) were all independently associated with SARS-CoV-2 IgM seropositivity. Out of the studied factors, living in the Ukerewe district was independently associated with IgG seropositivity (aOR 1.29, CI 1.08–1.54, p = 0.004). Twenty months after the first case of COVID-19 in Tanzania, about half of the studied population in Mwanza was seropositive for SARS-CoV-2. KW - SARS-CoV-2 KW - COVID-19 KW - seroprevalence KW - antibodies KW - Mwanza KW - Tanzania Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288134 SN - 1660-4601 VL - 19 IS - 18 ER - TY - JOUR A1 - Wurmb, Thomas A1 - Scholtes, Katja A1 - Kolibay, Felix A1 - Schorscher, Nora A1 - Ertl, Georg A1 - Ernestus, Ralf-Ingo A1 - Vogel, Ulrich A1 - Franke, Axel A1 - Kowalzik, Barbara T1 - Hospital preparedness for mass critical care during SARS-CoV-2 pandemic JF - Critical Care N2 - Mass critical care caused by the severe acute respiratory syndrome corona virus 2 pandemic poses an extreme challenge to hospitals. The primary goal of hospital disaster preparedness and response is to maintain conventional or contingency care for as long as possible. Crisis care must be delayed as long as possible by appropriate measures. Increasing the intensive care unit (ICU) capacities is essential. In order to adjust surge capacity, the reduction of planned, elective patient care is an adequate response. However, this involves numerous problems that must be solved with a sense of proportion. This paper summarises preparedness and response measures recommended to acute care hospitals. KW - Mass critical care KW - Disaster response KW - SARS-CoV-2 KW - Hospital emergency plan Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230201 VL - 24 ER - TY - JOUR A1 - Brehm, Klaus A1 - Hemer, Sarah A1 - Konrad, Christian A1 - Spiliotis, Markus A1 - Koziol, Uriel A1 - Schaack, Dominik A1 - Förster, Sabine A1 - Gelmedin, Verena A1 - Stadelmann, Britta A1 - Dandekar, Thomas A1 - Hemphill, Andrew T1 - Host insulin stimulates Echinococcus multilocularis insulin signalling pathways and larval development N2 - Background The metacestode of the tapeworm Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a lethal zoonosis. Infections are initiated through establishment of parasite larvae within the intermediate host’s liver, where high concentrations of insulin are present, followed by tumour-like growth of the metacestode in host organs. The molecular mechanisms determining the organ tropism of E. multilocularis or the influences of host hormones on parasite proliferation are poorly understood. Results Using in vitro cultivation systems for parasite larvae we show that physiological concentrations (10 nM) of human insulin significantly stimulate the formation of metacestode larvae from parasite stem cells and promote asexual growth of the metacestode. Addition of human insulin to parasite larvae led to increased glucose uptake and enhanced phosphorylation of Echinococcus insulin signalling components, including an insulin receptor-like kinase, EmIR1, for which we demonstrate predominant expression in the parasite’s glycogen storage cells. We also characterized a second insulin receptor family member, EmIR2, and demonstrated interaction of its ligand binding domain with human insulin in the yeast two-hybrid system. Addition of an insulin receptor inhibitor resulted in metacestode killing, prevented metacestode development from parasite stem cells, and impaired the activation of insulin signalling pathways through host insulin. Conclusions Our data indicate that host insulin acts as a stimulant for parasite development within the host liver and that E. multilocularis senses the host hormone through an evolutionarily conserved insulin signalling pathway. Hormonal host-parasite cross-communication, facilitated by the relatively close phylogenetic relationship between E. multilocularis and its mammalian hosts, thus appears to be important in the pathology of alveolar echinococcosis. This contributes to a closer understanding of organ tropism and parasite persistence in larval cestode infections. Furthermore, our data show that Echinococcus insulin signalling pathways are promising targets for the development of novel drugs. KW - Cestode KW - Tapeworm KW - Echinococcus KW - Echinococcosis KW - Insulin KW - Receptor kinase KW - Kinase inhibitor KW - Host-parasite interaction Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110357 ER -