@article{AbdaKrysciakKrohnMoltetal.2015,
  author    = {Abda, Ebrahim M. and Krysciak, Dagmar and Krohn-Molt, Ines and Mamat, Uwe and Schmeisser, Christel and F{\"o}rstner, Konrad U. and Schaible, Ulrich E. and Kohi, Thomas A. and Nieman, Stefan and Streit, Wolfgang R.},
  title     = {Phenotypic Heterogeneity Affects Stenotrophomonas maltophilia K279a Colony Morphotypes and \(\beta\)-Lactamase Expression},
  series = {Frontiers in Microbiology},
  volume    = {6},
  journal   = {Frontiers in Microbiology},
  number    = {1373},
  doi       = {10.3389/fmicb.2015.01373},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136446},
  year      = {2015},
  abstract  = {Phenotypic heterogeneity at the cellular level in response to various stresses, e.g., antibiotic treatment has been reported for a number of bacteria. In a clonal population, cell-to-cell variation may result in phenotypic heterogeneity that is a mechanism to survive changing environments including antibiotic therapy. Stenotrophomonas rnaltophilia has been frequently isolated from cystic fibrosis patients, can cause numerous infections in other organs and tissues, and is difficult to treat due to antibiotic resistances. S. maltophilia K279a produces the Li and L2 beta-lactamases in response to beta-lactam treatment. Here we report that the patient isolate S. rnaltophilia K279a diverges into cellular subpopulations with distinct but reversible morphotypes of small and big colonies when challenged with ampicillin. This observation is consistent with the formation of elongated chains of bacteria during exponential growth phase and the occurrence of mainly rod-shaped cells in liquid media. RNA-seq analysis of small versus big colonies revealed differential regulation of at least seven genes among the colony morphotypes. Among those, bleu and bla(L2) were transcriptionally the most strongly upregulated genes. Promoter fusions of b/a(L1) and b/a(L2) genes indicated that expression of both genes is also subject to high levels of phenotypic heterogeneous expression on a single cell level. Additionally, the comE homolog was found to be differentially expressed in homogenously versus heterogeneously bla(L2) expressing cells as identified by RNA(seq) analysis. Overexpression of cornE in S. maltophilia K279a reduced the level of cells that were in a bla(L2)-ON mode to 1\% or lower. Taken together, our data provide strong evidence that S. maltophilia K279a populations develop phenotypic heterogeneity in an ampicillin challenged model. This cellular variability is triggered by regulation networks including b/a(L1), b/a(L2), and comE.},
  language  = {en}
}
@article{AdelfingerGentschevdeGuibertetal.2014,
  author    = {Adelfinger, Marion and Gentschev, Ivaylo and de Guibert, Julio Grimm and Weibel, Stephanie and Langbein-Laugwitz, Johanna and H{\"a}rtl, Barbara and Escobar, Hugo Murua and Nolte, Ingo and Chen, Nanhai G. and Aguilar, Richard J. and Yu, Yong A. and Zhang, Qian and Frentzen, Alexa and Szalay, Aladar A.},
  title     = {Evaluation of a New Recombinant Oncolytic Vaccinia Virus Strain GLV-5b451 for Feline Mammary Carcinoma Therapy},
  series = {PLoS ONE},
  volume    = {9},
  journal   = {PLoS ONE},
  number    = {8},
  doi       = {10.1371/journal.pone.0104337},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119387},
  pages     = {e104337},
  year      = {2014},
  abstract  = {Virotherapy on the basis of oncolytic vaccinia virus (VACV) infection is a promising approach for cancer therapy. In this study we describe the establishment of a new preclinical model of feline mammary carcinoma (FMC) using a recently established cancer cell line, DT09/06. In addition, we evaluated a recombinant vaccinia virus strain, GLV-5b451, expressing the anti-vascular endothelial growth factor (VEGF) single-chain antibody (scAb) GLAF-2 as an oncolytic agent against FMC. Cell culture data demonstrate that GLV-5b451 virus efficiently infected, replicated in and destroyed DT09/06 cancer cells. In the selected xenografts of FMC, a single systemic administration of GLV-5b451 led to significant inhibition of tumor growth in comparison to untreated tumor-bearing mice. Furthermore, tumor-specific virus infection led to overproduction of functional scAb GLAF-2, which caused drastic reduction of intratumoral VEGF levels and inhibition of angiogenesis. In summary, here we have shown, for the first time, that the vaccinia virus strains and especially GLV-5b451 have great potential for effective treatment of FMC in animal model.},
  language  = {en}
}
@article{AfonsoGrunzHoffmeierMuelleretal.2015,
  author    = {Afonso-Grunz, Fabian and Hoffmeier, Klaus and M{\"u}ller, S{\"o}ren and Westermann, Alexander J. and Rotter, Bj{\"o}rn and Vogel, J{\"o}rg and Winter, Peter and Kahl, G{\"u}nter},
  title     = {Dual 3'Seq using deepSuperSAGE uncovers transcriptomes of interacting Salmonella enterica Typhimurium and human host cells},
  series = {BMC Genomics},
  volume    = {16},
  journal   = {BMC Genomics},
  number    = {323},
  doi       = {10.1186/s12864-015-1489-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143230},
  year      = {2015},
  abstract  = {Background: The interaction of eukaryotic host and prokaryotic pathogen cells is linked to specific changes in the cellular proteome, and consequently to infection-related gene expression patterns of the involved cells. To simultaneously assess the transcriptomes of both organisms during their interaction we developed dual 3'Seq, a tag-based sequencing protocol that allows for exact quantification of differentially expressed transcripts in interacting pro-and eukaryotic cells without prior fixation or physical disruption of the interaction. Results: Human epithelial cells were infected with Salmonella enterica Typhimurium as a model system for invasion of the intestinal epithelium, and the transcriptional response of the infected host cells together with the differential expression of invading and intracellular pathogen cells was determined by dual 3'Seq coupled with the next-generation sequencing-based transcriptome profiling technique deepSuperSAGE (deep Serial Analysis of Gene Expression). Annotation to reference transcriptomes comprising the operon structure of the employed S. enterica Typhimurium strain allowed for in silico separation of the interacting cells including quantification of polycistronic RNAs. Eighty-nine percent of the known loci are found to be transcribed in prokaryotic cells prior or subsequent to infection of the host, while 75\% of all protein-coding loci are represented in the polyadenylated transcriptomes of human host cells. Conclusions: Dual 3'Seq was alternatively coupled to MACE (Massive Analysis of cDNA ends) to assess the advantages and drawbacks of a library preparation procedure that allows for sequencing of longer fragments. Additionally, the identified expression patterns of both organisms were validated by qRT-PCR using three independent biological replicates, which confirmed that RELB along with NFKB1 and NFKB2 are involved in the initial immune response of epithelial cells after infection with S. enterica Typhimurium.},
  language  = {en}
}
@phdthesis{Agarwal2010,
  author    = {Agarwal, Shruti},
  title     = {Functional characterization of four CDK-like kinases and one Calmodulin-dependent kinase of the human malaria parasite, Plasmodium falciparum},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48522},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2010},
  abstract  = {Malaria still persists as one of the deadliest infectious disease in addition to AIDS and tuberculosis. lt is a leading cause of high mortality and morbidity rates in the developing world despite of groundbreaking research on global eradication of the disease initiated by WHO, about half a century ago. Lack of a commercially available vaccine and rapid spread of drug resistance have hampered the attempts of extinguishing malaria, which still leads to an annual death toll of about one million people. Resistance to anti-malarial compounds thus renders search for new target proteins imperative. The kinome of the human malaria parasite Plasmodium falciparum comprises representatives of most eukaryotic protein kinase groups, including kinases which regulate proliferation and differentiation processes. Several reports till date have suggested involvement of parasite kinases in the human host and as well as in the mosquito vector. Kinases essential for life cycle stages of the parasite represent promising targets for anti-malarial compounds thus, provoking characterization of additional malarial kinases. Despite extensive research on most plasmodial enzymes, very little information is available regarding the four identified members of the cyclin dependent kinase like kinase (CLK) family. Thus, the present thesis dealt with the functional characterization of four members of the PfCLK kinase family of the parasite denoted as PfCLK-1/Lammer, PfCLK-2, PfCLK-3 and PfCLK-4 with a special focus on the first two kinases. Additionally, one Ca2+/Calmodulin dependent putative kinase-related protein, PfPKRP, presumed to be involved in sexual stage development of the parasite, was investigated for its expression in the life cycle of the parasite. In other eukaryotes, CLK kinases regulate mRNA splicing through phosphorylation of Serine/Arginine-rich proteins. Transcription analysis revealed abundance of PfCLK kinase genes throughout the asexual blood stages and in gametocytes. By reverse genetics approach it was demonstrated that all four kinases are essential for completion of the asexual replication cycle of P. falciparum. PfCLK 1/Lammer possesses two nuclear localization signals and PfCLK-2 possesses one of these signals upstream of the C-terminal catalytic domains. Protein level expression and sub-cellular localization of the two kinases was determined by generation of antiserum directed against the kinase domains of the respective kinase. Indirect immunofluorescence, Western blot and electron microscopy data confirm that the kinases are primarily localized in the parasite nucleus, and in vitro assays show that both enzymes are associated with phosphorylation activity. Finally, mass spectrometric analysis of co immunoprecipitated proteins shows interactions of the two PfCLK kinases with proteins, which have putative nuclease, phosphatase or helicase functions. PfPKRP on the other hand is predominantly expressed during gametocyte differentiation as identified from transcriptional analysis. Antiserum directed against the catalytic domain of PfPKRP detected the protein expression profile in both asexual and gametocyte parasite lysates. Via immunofluorescence assay, the kinase was localized in the parasite cytoplasm in a punctuated manner, mostly in the gametocyte stages. Reverse genetics resulted in the generation of PfPKRP gene-disruptant parasites, thus demonstrating that unlike CLK kinases, PfPKRP is dispensable for asexual parasite survival and hence might have crucial role in sexual development of the parasite. On one hand, characterization of PfCLK kinases exemplified the kinases involved in parasite replication cycle. Successful gene-disruption and protein expression of PfPKRP kinase on the other hand, demonstrated a role of the kinase in sexual stage development of the parasite. Both kinase families therefore, represent potential candidates for anti-plasmodial compounds.},
  subject      = {Plasmodium falciparum},
  language  = {en}
}
@phdthesis{Agarwal2008,
  author    = {Agarwal, Vaibhav},
  title     = {Role of PspC interaction with human polymeric immunoglobulin receptor and Factor H in Streptococcus pneumoniae infections and host cell induced signalling},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-36526},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2008},
  abstract  = {Streptococcus pneumoniae ist ein Gram-positives Bakterium und ein Kommensale des humanen Nasenrachenraums. Pneumokokken sind andererseits auch die Verursacher schwerer lokaler Infektionen wie der Otitis media, Sinusitis und von lebensbedrohenden invasiven Erkrankungen. So sind Pneumokokken die wichtigsten Erreger einer ambulant erworbenen Pneumonie und sie sind h{\"a}ufige Verursacher von Septik{\"a}mien und bakteriellen Meningitiden. Die initiale Phase der Pathogenese ist verbunden mit der Besiedelung der mukosalen Epithelzellen des Rachenraumes. Diese Kolonisierung erleichtert die Aufnahme der Bakterien in die Zelle bzw. deren Dissemination in submukosale Bereiche und den Blutstrom. Die Konversion des Kommensalen zu einem invasiven Mikroorganismus ist assoziiert mit der Anpassung des Krankheitserregers an die verschiedenen Wirtsnischen und wird auf der Wirtsseite durch die Zerst{\"o}rung der transepithelialen Barriere begleitet. Die Anpassung des Erregers ist vermutlich ein in hohem Grade regulierter Prozess. Die Oberfl{\"a}che von Streptococcus pneumoniae ist mit Proteinen bedeckt, die kovalent oder nicht kovalent mit der Zellwand verkn{\"u}pft sind. Eine einzigartige Gruppe von Oberfl{\"a}chenproteinen in der Zellwand der Pneumokokken sind die cholinbindenden Proteine (CBPs). F{\"u}r einige der CBPs konnte bereits die Bedeutung f{\"u}r die Virulenz gezeigt werden. PspC, auch als SpsA oder CbpA bezeichnet, ist ein multifunktionales Oberfl{\"a}chenprotein, das als Adhesin und Faktor H-Bindungsprotein eine wichtige Rolle in der Pathogenese der Pneumokokken hat. PspC vermittelt als Adhesin die Anheftung der Bakterien an die mukosalen Epithelzellen, indem es human-spezifisch an die sekretorische Komponente (SC) des polymeren Immunoglobulinrezeptors (pIgR) bindet. SC ist die Ektodom{\"a}ne des pIgR und PspC kann ebenso die freie SC binden oder an die SC des sekretorischen IgA Molek{\"u}ls binden. PspC interagiert auch mit dem l{\"o}slichen Komplement Faktor H. Die SC und der Faktor erkennen zwei verschiedene Epitope im bakteriellen PspC Protein. Der genaue Mechanismus der jeweiligen Interaktionen unter physiologischen- bzw. wirtspezifischen Bedingungen ist noch nicht vollst{\"a}ndig verstanden. In dieser Arbeit wurde die Auswirkung der PspC Interaktion mit dem humanen pIgR (hpIgR) bzw. dem Faktor H auf die Virulenz der Pneumokokken und die Wirtszellantwort, d.h. die induzierten Signalkaskaden in den eukaryotischen Zellen untersucht. Die molekulare Analyse und die Verwendung von spezifischen pharmakologischen Inhibitoren der Signalmolek{\"u}le zeigten, dass verschiedene Signalmolek{\"u}le an der PspC-pIgR vermittelten Internalisierung beteiligt sind. Die Aktivierung, d.h. die Phosphorylierung der Signalmolek{\"u}le wurde in Immunblots demonstriert. Die Studien zeigten, dass das Aktinzytoskelett und die Mikrotubuli f{\"u}r die bakterielle Aufnahme essentiell sind. Es konnte auch zum ersten Mal nachgewiesen werden, dass Cdc42 die entscheidende GTPase f{\"u}r die Invasion der Pneumokokken in die Wirtsepithelzellen, vermittelt {\"u}ber den PspC-hpIgR Mechanismus, ist. Der Einsatz von PI3-kinase und Akt Kinase Inhibitoren reduzierte signifikant die hpIgR-vermittelte Aufnahme der Pneumokokken in die Wirtszelle. Zus{\"a}tzlich durchgef{\"u}hrte Infektionen von hpIgR exprimierenden Zellen zeigten eine zeitabh{\"a}ngige Phosphorylierung von Akt und der p85\&\#945; Untereinheit der PI3-Kinase. Damit ist neben der GTPase Cdc42 der PI3K und Akt Signalweg entscheidend f{\"u}r die PspC-pIgR vermittelte Invasion der Pneumokokken. Des Weiteren sind an der Infektion mit Pneumokokken auch die Protein Tyrosin Kinasen Src, ERK1/2 und JNK beteiligt. Dabei wird die Src Kinase unabh{\"a}ngig von der PI3K in hpIgR exprimierenden Zellen aktiviert. Inhibitionsexperimente und genetische Knockdown Versuche mit siRNA bewiesen, dass die Endozytose der Pneumokokken {\"u}ber PspC-pIgR ein Clathrin und Dynamin abh{\"a}ngiger Mechanismus ist. Im weiterenn Teil der Arbeit wurde der Einfluss des PspC gebundenen Faktor H auf die Anheftung an und Invasion in die Epithelzellen analysiert. Die Bindung von Faktor H erfolgte unabh{\"a}ngig vom PspC-Subtyp. Die Bindungsversuche bewiesen, dass die Kapselmenge negativ korreliert mit der Bindung des Faktor H. Der Einsatz von Faktor H aus Maus oder Ratte zeigte keine typische Bindung. Daraus kann abgeleitet werden, dass diese Interaktion humanspezifisch ist. Die Infektionsexperimente demonstrierten, dass Faktor H die Adh{\"a}renz und die Invasion der Bakterien in die Nasenrachenraumzellen (Detroit562), alveol{\"a}ren Lungenepithelzellen (A549) und humanen Hirnendothelzellen (HBMEC) steigert. Der Faktor H hat Heparin Bindestellen. Diese Bindestellen vermitteln die Adh{\"a}renz der Faktor H gebundenen Pneumokokken mit Epithelzellen. Inhibitionsstudien mit spezifischen monoklonalen Antik{\"o}rpern, die gegen die short consensus repeats (SCRs) von Faktor H gerichtet waren, konnten die essentielle Bedeutung der SCR19-20 f{\"u}r die Anheftung der Pneumokokken {\"u}ber Faktor H an die Wirtszellen nachweisen. Die Faktor H vermittelte Assoziation der Pneumokokken an polymorphonukle{\"a}re Leukozyten (PMNs) erfolgt {\"u}ber das Integrin CD11b/CD18. Die weiteren Inhibitionsstudien zeigten dann auch zum ersten Mal den Einfluss des Aktinzytoskeletts der Wirtszelle auf die Faktor H-vermittelten bakterieller Internalisierung und den dabei bedeutsamen Signaltransduktionswegen in der eukaryotischen Zelle. Dabei wurden insbesondere die Proteintyrosinkinasen und die PI3K als wichtige Signalmolek{\"u}le f{\"u}r die Faktor H vermittelte Invasion der Pneumokokken identifiziert. Die in dieser Arbeit erhaltenen Resultate belegen, dass die Faktor H vermittelte Infektion der Zellen mit S. pneumoniae ein konzertierter Mechanismus ist, bei dem Oberfl{\"a}chen-Glycosaminoglycane, Integrine und Signaltransduktionswege der Wirtsepithelzellen involviert sind. Des Weiteren wurde aufgezeigt, dass die PspC-pIgR-vermittelte Invasion in mukosale Epithelzellen unterschiedliche Signalwege wie z.B. den PI3K und Akt Weg induziert und abh{\"a}ngig von Cdc42 und einer Clathrin vermittelten Endozytosemechanismus ist.},
  subject      = {Streptococcus pneumoniae},
  language  = {en}
}
@phdthesis{Agerer2005,
  author    = {Agerer, Franziska},
  title     = {Integrin-vermittelte Invasion von Staphylococcus aureus in S{\"a}ugerzellen},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14557},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {Der Gram-positive Erreger Staphylococcus aureus ist ein Bestandteil der normalen Haut und Schleimhautflora des Menschen, kann aber auch ein weites Spektrum von Krankheitsbildern hervorrufen. Ein besonderes Charakteristikum dieses Pathogens besteht in der Expression von Oberfl{\"a}chenstrukturen, welche eine hohe Affinit{\"a}t f{\"u}r Proteine der extrazellul{\"a}ren Matrix (ECM) von eukaryontischen Organismen aufweisen und die kollektiv als MSCRAMM (microbial surface components recognizing adhesive matrix molecules) bezeichnet werden. Das auf der Bakterienoberfl{\"a}che gebundene Fn kann in der Folge als eine Art molekulare Br{\"u}cke zwischen FnBP exprimierenden S. aureus und dem Fn-Rezeptor auf der Wirtszellseite, dem Integrin 51, dienen. Neben der Anheftung an das Wirtsgewebe kann die indirekte Assoziation mit Integrin 51 die Aufnahme der Bakterien durch die eukaryontische Zelle ausl{\"o}sen. Wie die bakterielle Adh{\"a}sion an Integrin 51 und die Aggregation der Integrine durch die mit Fn-beschichteten Bakterien in ein Signal zur Aufnahme der Pathogene durch die Zelle umgesetzt wird, ist nicht vollst{\"a}ndig gekl{\"a}rt und sollte im Rahmen dieser Arbeit untersucht werden. Zu diesem Zweck wurde ein neues und effektives Protokoll zur fluoreszenzmikroskopischen Differenzierung von extra- und intrazellul{\"a}ren Bakterien entwickelt. Diese Methode besitzt den Vorteil, von Bakterien-spezifischen Antik{\"o}rpern unabh{\"a}ngig zu sein. Dadurch bietet sich die M{\"o}glichkeit, Bakterien, gegen die es noch keine spezifischen Antiseren gibt, dennoch auf ihre zellul{\"a}re Lokalisation und Invasivit{\"a}t mittels mikrobiologischer Methoden untersuchen zu k{\"o}nnen. Im Hinblick auf die n{\"a}here Untersuchung der Signaltransduktion bei der Invasion von S. aureus war die kritische Rolle von Tyrosinkinasen f{\"u}r die Integrin-vermittelte Invasion ein erster wichtiger Hinweis. Diese Befunde f{\"u}hrten zu weiteren spezifischeren Untersuchungen, wobei eine wichtige Rolle f{\"u}r Kinasen der Src Familie gezeigt werden konnte. Ein weiterer Hinweis auf die Bedeutung der Src-Kinasen f{\"u}r die Internalisierung von S. aureus war ein dramatischer R{\"u}ckgang der Aufnahmerate in Src/Yes/Fyn-defizienten Maus-Fibroblasten, verglichen mit Src-rekonstituierten Zellen. Auf biochemischer Ebene konnte eine deutliche Aktivierung der Src-Kinase nach einer Infektion mit S. aureus, nicht aber nach Infektion mit dem nicht-pathogenen S. carnosus festgestellt werden. Integrin-reiche fokale Kontakte (FK) sind angereichert mit Proteinen wie Talin, Vinculin, Paxillin, Tensin, -Actinin oder Zyxin sowie Signalenzymen wie der Fokalen Adh{\"a}sions Kinase (FAK) oder Kinasen der Src Familie. Die Protein Tyrosin Kinase (PTK) FAK ist nach Integrinstimulierung eines der Schl{\"u}sselenzyme in FK. Dies war der Anlass nach der Bedeutung von FAK f{\"u}r die Integrin-vermittelte Internalisierung von S. aureus zu fragen. Ebenfalls ein wichtiger Hinweis waren die starken Rekrutierungen von Markerproteinen von fokalen Komplexen zum Ort von zellgebunden S. aureus nicht aber von S. carnosus. Daraufhin wurde mittels dominant-negativer FAK-Mutanten und FAKdefizienter Mausfibroblasten der Einfluss von FAK f{\"u}r die Internalisierung von S. aureus untersucht. Bei beiden Versuchsans{\"a}tzen konnte ein starker R{\"u}ckgang der Aufnahme beobachtet werden. Zusammengefasst best{\"a}tigten diese Ergebnisse die essentielle Rolle von FAK f{\"u}r die Integrin vermittelte Aufnahme der pathogenen S. aureus. Bei der Reorganisation des Aktin-Zytoskeletts spielen eine Reihe von Proteinen eine wichtige Rolle, darunter auch Cortactin. Cortactin ist ein bekanntes Substrat der Src-Kinasen und es lag nahe, nach einer funktionellen Verbindung von Src, FAK und Cortactin zu suchen. Dominant-negative Cortactin-Mutanten, die keine Assoziation mit dem Arp2/3 Komplex oder mit Dynamin aufweisen, oder welche die von Src-vermittelte Phosphorylierung am C-Terminus verhindern, blockierten die Aufnahme von S. aureus. Mikroskopisch konnte eine starke Rekrutierung von Cortactin zu zellgebundenen S. aureus beobachtet werden, jedoch wurde die Rekrutierung nicht von FAK beeinflusst. Die Phosphorylierung von Cortactin aufgrund S. aureus-Infektion war allerdings FAK- und Src-abh{\"a}ngig. Diese Ergebnisse legen nahe, dass ine bisher unbeschriebene FAK/Src Cortactin Signalachse f{\"u}r die Regulation der Integrin-Internalisierung verantwortlich ist. Die detaillierten Untersuchungen der rezeptorvermittelten Aufnahme und der dabei induzierten Signaltransduktion in Wirtszellen gaben neue Erkenntnisse {\"u}ber die Pathogenit{\"a}tsstrategien von S. aureus. Dar{\"u}ber hinaus erm{\"o}glichen diese Arbeiten neue Einblicke in die molekularen Vorg{\"a}nge, welche die Internalisierung von Integrinen steuern.},
  subject      = {Staphylococcus aureus},
  language  = {de}
}
@phdthesis{AlbertWeissenberger2009,
  author    = {Albert-Weißenberger, Christiane},
  title     = {Regulation of the Flagellar Biogenesis in Legionella pneumophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34335},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2009},
  abstract  = {The bacterial pathogen Legionella pneumophila replicates intracellularly in protozoa, but can also cause severe pneumonia, called Legionnaires' disease. The bacteria invade and proliferate in the alveolar macrophages of the human lung. L. pneumophila bacteria exhibit a biphasic life cycle: replicative bacteria are avirulent; in contrast, transmissive bacteria express virulence traits and flagella. Primarily aim of this thesis was to evaluate the impact of the regulatory proteins FleQ, FleR, and RpoN in flagellar gene regulation. Phenotypic analysis, Western blot and electron microscopy of regulatory mutants in the genes coding for FleQ, RpoN and FleR demonstrated that flagellin expression is strongly repressed and that these mutants are non-flagellated in transmissive phase. Transcriptomic studies of these putative flagellar gene expression regulators demonstrated that fleQ controls the expression of numerous flagellar biosynthetic genes. Together with RpoN, FleQ controls transcription of 14 out of 31 flagellar class II genes, coding for the basal body, hook, and regulatory proteins. Unexpectedly, 7 out of 15 late flagellar genes class III and IV) are expressed dependent on FleQ but independent of RpoN. Thus, in contrast to the commonly accepted view that enhancer binding proteins as FleQ always interact with RpoN to initiate transcription, our results strongly indicate that FleQ of L. pneumophila regulates gene expression RpoN-dependent as well as RpoN-independent. Moreover, transcriptome analysis of a fleR mutant strain elucidated that FleR does not regulate the flagellar class III genes as previously suggested. Instead FleR regulates together with RpoN numerous protein biosynthesis and metabolic genes. Based on these experimental results our modified model for the transcriptional regulation of flagellar genes in L. pneumophila is that flagellar class II genes are controlled by FleQ and RpoN, while flagellar class III and IV genes are controlled in a fleQ-dependent but rpoN-independent manner. Although all L. pneumophila strains share the same complex life style, various pathotypes have evolved. This is reflected by the genomes, which contain e.g. genomic islands. The genomic island Trb-1 of L. pneumophila Corby, carries all genes necessary for a type-IV conjugation system, an integrase gene and a putative oriT site. The second aim of this thesis was to investigate the implication of this genomic island in conjugative DNA transfer. Using conjugation assays we showed that the oriT site located on Trb-1 is functional and contributes to conjugation between different L. pneumophila strains. As this is the first oriT site of L. pneumophila known to be functional our results provide evidence that conjugation is a major mechanism for the evolution of new pathotypes in L. pneumophila.},
  subject      = {Legionella pneumophila},
  language  = {en}
}
@article{AllertFoersterSvenssonetal.2018,
  author    = {Allert, Stefanie and F{\"o}rster, Toni M. and Svensson, Carl-Magnus and Richardson, Jonathan P. and Pawlik, Tony and Hebecker, Betty and Rudolphi, Sven and Juraschitz, Marc and Schaller, Martin and Blagojevic, Mariana and Morschh{\"a}user, Joachim and Figge, Marc Thilo and Jacobsen, Ilse D. and Naglik, Julian R. and Kasper, Lydia and Mogavero, Selene and Hube, Bernhard},
  title     = {\(Candida\) \(albicans\)-Induced Epithelial Damage Mediates Translocation through Intestinal Barriers},
  series = {mBio},
  volume    = {9},
  journal   = {mBio},
  number    = {3},
  doi       = {10.1128/mBio.00915-18},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221084},
  pages     = {1-20},
  year      = {2018},
  abstract  = {Life-threatening systemic infections often occur due to the translocation of pathogens across the gut barrier and into the bloodstream. While the microbial and host mechanisms permitting bacterial gut translocation are well characterized, these mechanisms are still unclear for fungal pathogens such as Candida albicans, a leading cause of nosocomial fungal bloodstream infections. In this study, we dissected the cellular mechanisms of translocation of C. albicans across intestinal epithelia in vitro and identified fungal genes associated with this process. We show that fungal translocation is a dynamic process initiated by invasion and followed by cellular damage and loss of epithelial integrity. A screen of >2,000 C. albicans deletion mutants identified genes required for cellular damage of and translocation across enterocytes. Correlation analysis suggests that hypha formation, barrier damage above a minimum threshold level, and a decreased epithelial integrity are required for efficient fungal translocation. Translocation occurs predominantly via a transcellular route, which is associated with fungus-induced necrotic epithelial damage, but not apoptotic cell death. The cytolytic peptide toxin of C. albicans, candidalysin, was found to be essential for damage of enterocytes and was a key factor in subsequent fungal translocation, suggesting that transcellular translocation of C. albicans through intestinal layers is mediated by candidalysin. However, fungal invasion and low-level translocation can also occur via non-transcellular routes in a candidalysin-independent manner. This is the first study showing translocation of a human-pathogenic fungus across the intestinal barrier being mediated by a peptide toxin. IMPORTANCE Candida albicans, usually a harmless fungus colonizing human mucosae, can cause lethal bloodstream infections when it manages to translocate across the intestinal epithelium. This can result from antibiotic treatment, immune dysfunction, or intestinal damage (e.g., during surgery). However, fungal processes may also contribute. In this study, we investigated the translocation process of C. albicans using in vitro cell culture models. Translocation occurs as a stepwise process starting with invasion, followed by epithelial damage and loss of epithelial integrity. The ability to secrete candidalysin, a peptide toxin deriving from the hyphal protein Ece1, is key: C. albicans hyphae, secreting candidalysin, take advantage of a necrotic weakened epithelium to translocate through the intestinal layer.},
  language  = {en}
}
@phdthesis{Alzheimer2023,
  author    = {Alzheimer, Mona},
  title     = {Development of tissue-engineered three-dimensional infection models to study pathogenesis of \(Campylobacter\) \(jejuni\)},
  doi       = {10.25972/OPUS-19344},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193440},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Infectious diseases caused by pathogenic microorganisms are one of the largest socioeconomic burdens today. Although infectious diseases have been studied for decades, in numerous cases, the precise mechanisms involved in the multifaceted interaction between pathogen and host continue to be elusive. Thus, it still remains a challenge for researchers worldwide to develop novel strategies to investigate the molecular context of infectious diseases in order to devise preventive or at least anti-infective measures. One of the major drawbacks in trying to obtain in-depth knowledge of how bacterial pathogens elicit disease is the lack of suitable infection models to authentically mimic the disease progression in humans. Numerous studies rely on animal models to emulate the complex temporal interactions between host and pathogen occurring in humans. While they have greatly contributed to shed light on these interactions, they require high maintenance costs, are afflicted with ethical drawbacks, and are not always predictive for the infection outcome in human patients. Alternatively, in-vitro two-dimensional (2D) cell culture systems have served for decades as representatives of human host environments to study infectious diseases. These cell line-based models have been essential in uncovering virulence-determining factors of diverse pathogens as well as host defense mechanisms upon infection. However, they lack the morphological and cellular complexity of intact human tissues, limiting the insights than can be gained from studying host-pathogen interactions in these systems. The focus of this thesis was to establish and innovate intestinal human cell culture models to obtain in-vitro reconstructed three-dimensional (3D) tissue that can faithfully mimic pathogenesis-determining processes of the zoonotic bacterium Campylobacter jejuni (C. jejuni). Generally employed for reconstructive medicine, the field of tissue engineering provides excellent tools to generate organ-specific cell culture models in vitro, realistically recapitulating the distinctive architecture of human tissues. The models employed in this thesis are based on decellularized extracellular matrix (ECM) scaffolds of porcine intestinal origin. Reseeded with intestinal human cells, application of dynamic culture conditions promoted the formation of a highly polarized mucosal epithelium maintained by functional tight and adherens junctions. While most other in-vitro infection systems are limited to a flat monolayer, the tissue models developed in this thesis can display the characteristic 3D villi and crypt structure of human small intestine. First, experimental conditions were established for infection of a previously developed, statically cultivated intestinal tissue model with C. jejuni. This included successful isolation of bacterial colony forming units (CFUs), measurement of epithelial barrier function, as well as immunohistochemical and histological staining techniques. In this way, it became possible to follow the number of viable bacteria during the infection process as well as their translocation over the polarized epithelium of the tissue model. Upon infection with C. jejuni, disruption of tight and adherens junctions could be observed via confocal microscopy and permeability measurements of the epithelial barrier. Moreover, C. jejuni wildtype-specific colonization and barrier disruption became apparent in addition to niche-dependent bacterial localization within the 3D microarchitecture of the tissue model. Pathogenesis-related phenotypes of C. jejuni mutant strains in the 3D host environment deviated from those obtained with conventional in-vitro 2D monolayers but mimicked observations made in vivo. Furthermore, a genome-wide screen of a C. jejuni mutant library revealed significant differences for bacterial factors required or dispensable for interactions with unpolarized host cells or the highly prismatic epithelium provided by the intestinal tissue model. Elucidating the role of several previously uncharacterized factors specifically important for efficient colonization of a 3D human environment, promises to be an intriguing task for future research. At the frontline of the defense against invading pathogens is the protective, viscoelastic mucus layer overlying mucosal surfaces along the human gastrointestinal tract (GIT). The development of a mucus-producing 3D tissue model in this thesis was a vital step towards gaining a deeper understanding of the interdependency between bacterial pathogens and host-site specific mucins. The presence of a mucus layer conferred C. jejuni wildtype-specific protection against epithelial barrier disruption by the pathogen and prevented a high bacterial burden during the course of infection. Moreover, results obtained in this thesis provide evidence in vitro that the characteristic corkscrew morphology of C. jejuni indeed grants a distinct advantage in colonizing mucous surfaces. Overall, the results obtained within this thesis highlight the strength of the tissue models to combine crucial features of native human intestine into accessible in-vitro infection models. Translation of these systems into infection research demonstrated their ability to expose in-vivo like infection outcomes. While displaying complex organotypic architecture and highly prismatic cellular morphology, these tissue models still represent an imperfect reflection of human tissue. Future advancements towards inclusion of human primary and immune cells will strive for even more comprehensive model systems exhibiting intricate multicellular networks of in-vivo tissue. Nevertheless, the work presented in this thesis emphasizes the necessity to investigate host-pathogen interactions in infection models authentically mimicking the natural host environment, as they remain among the most vital parts in understanding and counteracting infectious diseases.},
  subject      = {Campylobacter jejuni},
  language  = {en}
}
@article{AlzheimerSvenssonKoenigetal.2020,
  author    = {Alzheimer, Mona and Svensson, Sarah L. and K{\"o}nig, Fabian and Schweinlin, Matthias and Metzger, Marco and Walles, Heike and Sharma, Cynthia M.},
  title     = {A three-dimensional intestinal tissue model reveals factors and small regulatory RNAs important for colonization with Campylobacter jejuni},
  series = {PLoS Pathogens},
  volume    = {16},
  journal   = {PLoS Pathogens},
  number    = {2},
  doi       = {10.1371/journal.ppat.1008304},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229454},
  year      = {2020},
  abstract  = {The Gram-negative Epsilonproteobacterium Campylobacter jejuni is currently the most prevalent bacterial foodborne pathogen. Like for many other human pathogens, infection studies with C. jejuni mainly employ artificial animal or cell culture models that can be limited in their ability to reflect the in-vivo environment within the human host. Here, we report the development and application of a human three-dimensional (3D) infection model based on tissue engineering to study host-pathogen interactions. Our intestinal 3D tissue model is built on a decellularized extracellular matrix scaffold, which is reseeded with human Caco-2 cells. Dynamic culture conditions enable the formation of a polarized mucosal epithelial barrier reminiscent of the 3D microarchitecture of the human small intestine. Infection with C. jejuni demonstrates that the 3D tissue model can reveal isolate-dependent colonization and barrier disruption phenotypes accompanied by perturbed localization of cell-cell junctions. Pathogenesis-related phenotypes of C. jejuni mutant strains in the 3D model deviated from those obtained with 2D-monolayers, but recapitulated phenotypes previously observed in animal models. Moreover, we demonstrate the involvement of a small regulatory RNA pair, CJnc180/190, during infections and observe different phenotypes of CJnc180/190 mutant strains in 2D vs. 3D infection models. Hereby, the CJnc190 sRNA exerts its pathogenic influence, at least in part, via repression of PtmG, which is involved in flagellin modification. Our results suggest that the Caco-2 cell-based 3D tissue model is a valuable and biologically relevant tool between in-vitro and in-vivo infection models to study virulence of C. jejuni and other gastrointestinal pathogens.},
  language  = {en}
}
@article{AmichKrappmann2012,
  author    = {Amich, Jorge and Krappmann, Sven},
  title     = {Deciphering metabolic traits of the fungal pathogen Aspergillus fumigatus: redundancy vs. essentiality},
  series = {Frontiers in Microbiology},
  volume    = {3},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2012.00414},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123669},
  pages     = {414},
  year      = {2012},
  abstract  = {Incidence rates of infections caused by environmental opportunistic fungi have risen over recent decades. Aspergillus species have emerged as serious threat for the immunecompromised, and detailed knowledge about virulence-determining traits is crucial for drug target identification. As a prime saprobe, A. fumigatus has evolved to efficiently adapt to various stresses and to sustain nutritional supply by osmotrophy, which is characterized by extracellular substrate digestion followed by efficient uptake of breakdown products that are then fed into the fungal primary metabolism. These intrinsic metabolic features are believed to be related with its virulence ability. The plethora of genes that encode underlying effectors has hampered their in-depth analysis with respect to pathogenesis. Recent developments in Aspergillus molecular biology allow conditional gene expression or comprehensive targeting of gene families to cope with redundancy. Furthermore, identification of essential genes that are intrinsically connected to virulence opens accurate perspectives for novel targets in antifungal therapy.},
  language  = {en}
}
@article{AmichSchaffererHaasetal.2013,
  author    = {Amich, Jorge and Schafferer, Lukas and Haas, Hubertus and Krappmann, Sven},
  title     = {Regulation of Sulphur Assimilation Is Essential for Virulence and Affects Iron Homeostasis of the Human-Pathogenic Mould Aspergillus fumigatus},
  series = {PLoS Pathogens},
  volume    = {9},
  journal   = {PLoS Pathogens},
  number    = {8},
  doi       = {10.1371/journal.ppat.1003573},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130372},
  pages     = {e1003573},
  year      = {2013},
  abstract  = {Abstract Sulphur is an essential element that all pathogens have to absorb from their surroundings in order to grow inside their infected host. Despite its importance, the relevance of sulphur assimilation in fungal virulence is largely unexplored. Here we report a role of the bZIP transcription factor MetR in sulphur assimilation and virulence of the human pathogen Aspergillus fumigatus. The MetR regulator is essential for growth on a variety of sulphur sources; remarkably, it is fundamental for assimilation of inorganic S-sources but dispensable for utilization of methionine. Accordingly, it strongly supports expression of genes directly related to inorganic sulphur assimilation but not of genes connected to methionine metabolism. On a broader scale, MetR orchestrates the comprehensive transcriptional adaptation to sulphur-starving conditions as demonstrated by digital gene expression analysis. Surprisingly, A. fumigatus is able to utilize volatile sulphur compounds produced by its methionine catabolism, a process that has not been described before and that is MetR-dependent. The A. fumigatus MetR transcriptional activator is important for virulence in both leukopenic mice and an alternative mini-host model of aspergillosis, as it was essential for the development of pulmonary aspergillosis and supported the systemic dissemination of the fungus. MetR action under sulphur-starving conditions is further required for proper iron regulation, which links regulation of sulphur metabolism to iron homeostasis and demonstrates an unprecedented regulatory crosstalk. Taken together, this study provides evidence that regulation of sulphur assimilation is not only crucial for A. fumigatus virulence but also affects the balance of iron in this prime opportunistic pathogen. Author Summary Invasive pulmonary aspergillosis (IPA) is a life-threatening disease that affects primarily immunosuppressed patients. During the last decades the incidence of this disease that is accompanied by high mortality rates has increased. Since opportunistic pathogenic fungi, unlike other pathogens, do not express specific virulence factors, it is becoming more and more clear that the elucidation of fungal metabolism is an essential task to understand fungal pathogenicity and to identify novel antifungal targets. In this work we report genetic inactivation of the sulphur transcription regulator MetR in Aspergillus fumigatus and subsequent study of the resulting phenotypes and transcriptional deregulation of the mutant. Here we show that regulation of sulphur assimilation is an essential process for the manifestation of IPA. Moreover, a regulatory connection between sulphur metabolism and iron homeostasis, a further essential virulence determinant of A. fumigatus, is demonstrated in this study for the first time. A deeper knowledge of sulphur metabolism holds the promise of increasing our understanding of fungal virulence and might lead to improved antifungal therapy.},
  language  = {en}
}
@phdthesis{Aminake2012,
  author    = {Aminake, Makoah Nigel},
  title     = {Towards malaria combination therapy: Characterization of hybrid molecules for HIV/malaria combination therapy and of thiostrepton as a proteasome-targeting antibiotic with a dual mode of action},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71841},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {Malaria and HIV are among the most important global health problems of our time and together are responsible for approximately 3 million deaths annually. These two diseases overlap in many regions of the world including sub-Saharan Africa, Southeast Asia and South America, leading to a higher risk of co-infection. In this study, we generated and characterized hybrid molecules to target P. falciparum and HIV simultaneously for a potential HIV/malaria combination therapy. Hybrid molecules were synthesized by covalent fusion between azidothymidine (AZT) and dihydroartemisinin (DHA), tetraoxane or chloroquine (CQ); and a small library was generated and tested for antiviral and antimalarial activity. Our data suggest that dihyate is the most potent molecule in vitro, with antiplasmodial activity comparable to that of DHA (IC50 = 26 nM, SI > 3000), a moderate activity against HIV (IC50 = 2.9 µM; SI > 35) and safe to HeLa cells at concentrations used in the assay (CC50 > 100 µM). Pharmacokinetic studies further revealed that dihyate is metabolically unstable and is cleaved following an O-dealkylation once in contact with cytochrome P450 enzymes. The later further explains the uneffectiveness of dihyate against the CQ-sensitive P. berghei N strain in mice when administered by oral route at 20 mg/kg. Here, we report on a first approach to develop antimalarial/anti-HIV hybrid molecules and future optimization efforts will aim at producing second generation hybrid molecules to improve activity against HIV as well as compound bioavailability. With the emergence of resistant parasites against all the counterpart drugs of artemisinin derivatives used in artemisinin based combination therapies (ACTs), the introduction of antibiotics in the treatment of malaria has renewed interest on the identification of antibiotics with potent antimalarial properties. In this study we also investigated the antiplasmodial potential of thiostrepton and derivatives, synthesized using combinations of tail truncation, oxidation, and addition of lipophilic thiols to the terminal dehydroamino acid. We showed that derivatives SS231 and SS234 exhibit a better antiplasmodial activity (IC50 = 1 µM SI > 59 and SI > 77 respectively) than thiostrepton (IC50 = 8.95 µM, SI = 1.7). The antiplasmodial activity of these derivatives was observed at concentrations which are not hemolytic and non-toxic to human cell lines. Thiostrepton and derivatives appeared to exhibit transmission blocking properties when administered at their IC50 or IC90 concentrations and our data also showed that they attenuate proteasome activity of Plasmodium, which resulted in an accumulation of ubiquitinated proteins after incubation with their IC80 concentrations. Our results indicate that the parasite's proteasome could be an attractive target for therapeutic intervention. In this regard, thiostrepton derivatives are promising candidates by dually acting on two independent targets, the proteasome and the apicoplast, with the capacity to eliminate both intraerythrocytic asexual and transmission stages of the parasite. To further support our findings, we evaluated the activity of a new class of antimalarial and proteasome inhibitors namely peptidyl sulfonyl fluorides on gametocyte maturation and analogues AJ34 and AJ38 were able to completely suppress gametocytogenesis at IC50 concentrations (0.23 µM and 0.17 µM respectively) suggesting a strong transmission blocking potential. The proteasome, a major proteolytic complex, responsible for the degradation and re-cycling of non-functional proteins has been studied only indirectly in P. falciparum. In addition, an apparent proteasome-like protein with similarity to bacterial ClpQ/hslV threonine-peptidases was predicted in the parasite. Antibodies were generated against the proteasome subunits alpha type 5 (α5-SU), beta type 5 (β5-SU) and pfhslV in mice and we showed that the proteasome is expressed in both sexual and asexual blood stages of P. falciparum, where they localize in the nucleus and in the cytoplasm. However, expression of PfhslV was only observed in trophozoites and shizonts. The trafficking of the studied proteasome subunits was further investigated by generating parasites expressing GFP tagged proteins. The expression of α5-SU-GFP in transgenic parasite appeared to localize abundantly in the cytoplasm of all blood stages, and no additional information was obtained from this parasite line. In conclusion, our data highlight two new tools towards combination therapy. Hybrid molecules represent promising tools for the cure of co-infected individuals, while very potent antibiotics with a wide scope of activities could be useful in ACTs by eliminating resistant parasites and limiting transmission of both, resistances and disease.},
  subject      = {Malaria},
  language  = {en}
}
@phdthesis{Angermeier2011,
  author    = {Angermeier, Hilde Gabriele},
  title     = {Molecular and ecological investigations of Caribbean sponge diseases},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-56855},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {W{\"a}hrend gewinnbringende Assoziationen von Schw{\"a}mmen mit Mikroorganismen in den letzten Jahren viel Aufmerksamkeit erhalten haben, wurde weit weniger in die Interaktion von Schw{\"a}mmen mit m{\"o}glicherweise pathogenen Mikroben investiert. Somit war es das Ziel dieser Studie zwei ausgew{\"a}hlte Karibische Schwammkrankheiten namens „Sponge Orange Band" und „Sponge White Patch" mittels {\"o}kologischer und molekularer Methoden zu untersuchen. Die Sponge Orange Band (SOB) Erkrankung bef{\"a}llt den bedeutenden karibischen Fass-Schwamm Xestospongia muta, der zu den bakterienhaltigen (HMA) Schw{\"a}mmen gez{\"a}hlt wird, w{\"a}hrend die Sponge White Patch (SWP) Erkrankung den h{\"a}ufig vorkommenden Seil-Schwamm Amphimedon compressa betrifft, der zu den bakterienarmen (LMA) Schw{\"a}mmen geh{\"o}rt. F{\"u}r beide Karibischen Schwammkrankheiten konnte ich einen Krankheitsverlauf beschreiben, der mit massiver Gewebszerst{\"o}rung und dem Verlust charakteristischer mikrobieller Signaturen einhergeht. Obwohl ich zeigen konnte, dass zus{\"a}tzliche Bakterienarten die gebleichten Schwammbereiche kolonisieren, lieferten meine Infektionsversuche in beiden F{\"a}llen keinen Beweis f{\"u}r die Beteiligung eines mikrobiellen Pathogens als Krankheitserreger. Somit liegen die eigentlichen Ausl{\"o}ser der Erkrankungen Sponge Orange Band als auch Sponge White Patch noch immer im Dunkeln.},
  subject      = {Meeresschw{\"a}mme},
  language  = {en}
}
@article{AshrafYasrebiHertleinetal.2017,
  author    = {Ashraf, Kerolos and Yasrebi, Kaveh and Hertlein, Tobias and Ohlsen, Knut and Lalk, Michael and Hilgeroth, Andreas},
  title     = {Novel effective small-molecule antibacterials against \(Enterococcus\) strains},
  series = {Molecules},
  volume    = {22},
  journal   = {Molecules},
  number    = {12},
  doi       = {10.3390/molecules22122193},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172628},
  year      = {2017},
  abstract  = {\(Enterococcus\) species cause increasing numbers of infections in hospitals. They contribute to the increasing mortality rates, mostly in patients with comorbidities, who suffer from severe diseases. \(Enterococcus\) resistances against most antibiotics have been described, including novel antibiotics. Therefore, there is an ongoing demand for novel types of antibiotics that may overcome bacterial resistances. We discovered a novel class of antibiotics resulting from a simple one-pot reaction of indole and \(o\)-phthaldialdehyde. Differently substituted indolyl benzocarbazoles were yielded. Both the indole substitution and the positioning at the molecular scaffold influence the antibacterial activity towards the various strains of \(Enterococcus\) species with the highest relevance to nosocomial infections. Structure-activity relationships are discussed, and the first lead compounds were identified as also being effective in the case of a vancomycin resistance.},
  language  = {en}
}
@article{BabskiHaasNaetherSchindleretal.2016,
  author    = {Babski, Julia and Haas, Karina A. and N{\"a}ther-Schindler, Daniela and Pfeiffer, Friedhelm and F{\"o}rstner, Konrad U. and Hammelmann, Matthias and Hilker, Rolf and Becker, Anke and Sharma, Cynthia M. and Marchfelder, Anita and Soppa, J{\"o}rg},
  title     = {Genome-wide identification of transcriptional start sites in the haloarchaeon Haloferax volcanii based on differential RNA-Seq (dRNA-Seq)},
  series = {BMC Genomics},
  volume    = {17},
  journal   = {BMC Genomics},
  number    = {629},
  doi       = {10.1186/s12864-016-2920-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164553},
  year      = {2016},
  abstract  = {Background Differential RNA-Seq (dRNA-Seq) is a recently developed method of performing primary transcriptome analyses that allows for the genome-wide mapping of transcriptional start sites (TSSs) and the identification of novel transcripts. Although the transcriptomes of diverse bacterial species have been characterized by dRNA-Seq, the transcriptome analysis of archaeal species is still rather limited. Therefore, we used dRNA-Seq to characterize the primary transcriptome of the model archaeon Haloferax volcanii. Results Three independent cultures of Hfx. volcanii grown under optimal conditions to the mid-exponential growth phase were used to determine the primary transcriptome and map the 5′-ends of the transcripts. In total, 4749 potential TSSs were detected. A position weight matrix (PWM) was derived for the promoter predictions, and the results showed that 64 \% of the TSSs were preceded by stringent or relaxed basal promoters. Of the identified TSSs, 1851 belonged to protein-coding genes. Thus, fewer than half (46 \%) of the 4040 protein-coding genes were expressed under optimal growth conditions. Seventy-two percent of all protein-coding transcripts were leaderless, which emphasized that this pathway is the major pathway for translation initiation in haloarchaea. A total of 2898 of the TSSs belonged to potential non-coding RNAs, which accounted for an unexpectedly high fraction (61 \%) of all transcripts. Most of the non-coding TSSs had not been previously described (2792) and represented novel sequences (59 \% of all TSSs). A large fraction of the potential novel non-coding transcripts were cis-antisense RNAs (1244 aTSSs). A strong negative correlation between the levels of antisense transcripts and cognate sense mRNAs was found, which suggested that the negative regulation of gene expression via antisense RNAs may play an important role in haloarchaea. The other types of novel non-coding transcripts corresponded to internal transcripts overlapping with mRNAs (1153 iTSSs) and intergenic small RNA (sRNA) candidates (395 TSSs). Conclusion This study provides a comprehensive map of the primary transcriptome of Hfx. volcanii grown under optimal conditions. Fewer than half of all protein-coding genes have been transcribed under these conditions. Unexpectedly, more than half of the detected TSSs belonged to several classes of non-coding RNAs. Thus, RNA-based regulation appears to play a more important role in haloarchaea than previously anticipated.},
  language  = {en}
}
@phdthesis{Bader2005,
  author    = {Bader, Teresa Anna},
  title     = {Funktionelle Analysen virulenzrelevanter und essentieller Gene in Candida albicans},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12894},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {Die Bedeutung von Mykosen hat wegen der wachsenden Zahl immunsupprimierter Patienten in den letzten Jahren immer mehr zugenommen. Diese erkranken h{\"a}ufig an oberfl{\"a}chlichen sowie lebensbedrohlichen systemischen Infektionen mit dem opportunistisch humanpathogenen Hefepilz Candida albicans, da der Keim, der oftmals als harmloser Kommensale auf den Schleimh{\"a}uten im Gastrointestinaltrakt gesunder Menschen vorkommt, vom geschw{\"a}chten Immunsystem nicht mehr in Schach gehalten werden kann. In dieser Arbeit sollten bestimmte Gene von C. albicans, die in anderen Organismen als essentiell f{\"u}r deren Lebensf{\"a}higkeit bzw. Virulenz beschrieben wurden, als potentielle Zielstrukturen f{\"u}r die Entwicklung neuer Antimykotika charakterisiert werden. Das CMP1-Gen kodiert f{\"u}r die katalytische Untereinheit der konservierten Calcium/Calmodulin-abh{\"a}ngigen Phosphatase Calcineurin, die in der B{\"a}ckerhefe Saccharomyces cerevisiae und in anderen Organismen verschiedene physiologische Prozesse reguliert und essentiell f{\"u}r die Virulenz des pathogenen Hefepilzes Cryptococcus neoformans ist. Um die Bedeutung von Calcineurin f{\"u}r das {\"U}berleben und die Virulenz von C. albicans zu untersuchen, wurden homozygote cmp1 knock-out-Mutanten sowohl in einem auxotrophen C. albicans-Laborstamm als auch, mit Hilfe eines neuen dominanten Selektionsmarkers, in einem prototrophen Wildstamm hergestellt. Die Mutanten erwiesen sich als hypersensitiv gegen{\"u}ber Natrium, Calcium, Mangan und Lithium sowie gegen{\"u}ber alkalischem pH-Wert. Dar{\"u}ber hinaus konnten die mutierten Zellen Membranstreß, der durch SDS- oder Fluconazol-Zugabe verursacht wurde, nicht tolerieren und waren unter diesen Bedingungen stark in ihrem Wachstum gehemmt. Andere wichtige Virulenzeigenschaften wie die Toleranz gegen{\"u}ber Wirts-K{\"o}rpertemperatur und die F{\"a}higkeit zur Hyphenbildung zeigten sich durch die CMP1-Deletion in vitro nicht beeintr{\"a}chtigt. Dennoch machte die Anwendung eines murinen Modells einer systemischen Candidose in vivo deutlich, daß die Mutanten sehr stark in ihrer Virulenz attenuiert waren. Der Virulenzdefekt war vermutlich zumindest zum Teil dadurch bedingt, daß die Calcineurin-defizienten Zellen im Gegensatz zum Wildtyp in humanem Serum nicht wachsen konnten und deshalb m{\"o}glicherweise schlechter {\"u}ber die Blutbahn disseminieren konnten. Außer Calcineurin wurden in Kooperation mit einem Industriepartner drei weitere Gene, YML127, YPR143, und YML93, die in S. cerevisiae als essentiell beschrieben wurden und die keine signifikanten Homologien zu Vertebraten-Genen aufwiesen, in der C. albicans-Genomsequenz identifiziert und auf ihre Eignung als potentielle Targets hin untersucht. Die Funktion dieser Gene war zu Beginn dieser Arbeit unbekannt; vor kurzem wurde jedoch gezeigt, daß sie in S. cerevisiae eine Rolle beim Chromatin-Remodeling bzw. bei der rRNA-Prozessierung haben. Nachdem sich alle Gene auch in C. albicans als essentiell herausgestellt hatten, wurden konditional letale Mutanten hergestellt, in denen die Gene durch induzierbare Deletion mit Hilfe der site-spezifischen Rekombinase FLP aus dem Genom entfernt wurden. Dadurch wurde eine Population von Nullmutanten erhalten, in denen der terminale Ph{\"a}notyp der Gendeletion analysiert werden konnte. Die funktionelle Analyse des YML127 (RSC9) Gens wies darauf hin, daß es in C. albicans eine {\"a}hnliche Funktion hat wie in der B{\"a}ckerhefe, in der das Rsc9-Protein ein Bestandteil des RSC-Protein-Komplexes ist, der die Struktur des Chromatins in Abh{\"a}ngigkeit von Zellzyklus und Umweltbedingungen umorganisiert und damit die Aktivit{\"a}t von Genen steuert. Mit Hilfe eines HA-Epitop markierten YML127-Gens konnte das Genprodukt im Zellkern von C. albicans lokalisiert werden. Die C. albicans yml127-Nullmutanten produzierten verl{\"a}ngerte, mehrfach knospende Zellen, was einen Verlust der Koordination zwischen Mitose und Zytokinese vermuten ließ. Die beiden Gene YPR143 und YML93 (UTP14) scheinen wie ihre homologen Vertreter in S. cerevisiae an der Prozessierung der ribosomalen RNA beteiligt zu sein. Heterozygote Mutanten wiesen eine Haploinsuffizienz auf, die sich in einer erh{\"o}hten Suszeptibilit{\"a}t gegen{\"u}ber Hemmstoffen der rRNA-Synthese und der Ribosomenaktivit{\"a}t zeigte, und in den induzierten Nullmutanten akkumulierten Vorstufen der reifen rRNAs. In beiden F{\"a}llen f{\"u}hrte die Gendeletion zu Anomalien im Zellzyklus; die ypr143-Mutanten wiesen eine vergr{\"o}ßerte unf{\"o}rmige Zellmorphologie auf, und die yml93-Mutanten bildeten große, rundliche Zellen. Die Ergebnisse dieser Arbeit erlauben nicht nur wichtige Einblicke in die Funktion der untersuchten Gene in essentiellen zellul{\"a}ren Prozessen, sondern zeigen auch deren Bedeutung f{\"u}r die Virulenz bzw. f{\"u}r das {\"U}berleben des humanpathogenen Hefepilzes C. albicans. Die entsprechenden Genprodukte sollten sich deshalb prinzipiell als Angriffspunkte f{\"u}r die Entwicklung neuer antimykotischer Medikamente eignen.},
  subject      = {Candida albicans},
  language  = {de}
}
@article{BalasubramanianOthmanKampiketal.2017,
  author    = {Balasubramanian, Srikkanth and Othman, Eman M. and Kampik, Daniel and Stopper, Helga and Hentschel, Ute and Ziebuhr, Wilma and Oelschlaeger, Tobias A. and Abdelmohsen, Usama R.},
  title     = {Marine sponge-derived Streptomyces sp SBT343 extract inhibits staphylococcal biofilm formation},
  series = {Frontiers in Microbiology},
  volume    = {8},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2017.00236},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171844},
  year      = {2017},
  abstract  = {Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to absence of cell toxicity, the extract might represent a good starting material to develop a future remedy to block staphylococcal biofilm formation on contact lenses and thereby to prevent intractable contact lens-mediated ocular infections.},
  language  = {en}
}
@article{BalasubramanianSkafHolzgrabeetal.2018,
  author    = {Balasubramanian, Srikkanth and Skaf, Joseph and Holzgrabe, Ulrike and Bharti, Richa and F{\"o}rstner, Konrad U. and Ziebuhr, Wilma and Humeida, Ute H. and Abdelmohsen, Usama R. and Oelschlaeger, Tobias A.},
  title     = {A new bioactive compound from the marine sponge-derived Streptomyces sp. SBT348 inhibits staphylococcal growth and biofilm formation},
  series = {Frontiers in Microbiology},
  volume    = {9},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2018.01473},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221408},
  year      = {2018},
  abstract  = {Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 \(\mu\)g/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 \(\mu\)g/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs.},
  language  = {en}
}
@article{BandyraSaidPfeifferetal.2012,
  author    = {Bandyra, Katarzyna J. and Said, Nelly and Pfeiffer, Verena and G{\´o}rna, Maria W. and Vogel, J{\"o}rg and Luisi, Ben F.},
  title     = {The Seed Region of a Small RNA Drives the Controlled Destruction of the Target mRNA by the Endoribonuclease RNase E},
  series = {Molecular Cell},
  volume    = {47},
  journal   = {Molecular Cell},
  number    = {6},
  doi       = {10.1016/j.molcel.2012.07.015},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126202},
  pages     = {943-953},
  year      = {2012},
  abstract  = {Numerous small non-coding RNAs (sRNAs) in bacteria modulate rates of translation initiation and degradation of target mRNAs, which they recognize through base-pairing facilitated by the RNA chaperone Hfq. Recent evidence indicates that the ternary complex of Hfq, sRNA and mRNA guides endoribonuclease RNase E to initiate turnover of both the RNAs. We show that a sRNA not only guides RNase E to a defined site in a target RNA, but also allosterically activates the enzyme by presenting a monophosphate group at the 5′-end of the cognate-pairing "seed." Moreover, in the absence of the target the 5′-monophosphate makes the sRNA seed region vulnerable to an attack by RNase E against which Hfq confers no protection. These results suggest that the chemical signature and pairing status of the sRNA seed region may help to both 'proofread' recognition and activate mRNA cleavage, as part of a dynamic process involving cooperation of RNA, Hfq and RNase E.},
  language  = {en}
}