TY  - JOUR
A1  - Abdali, Narges
A1  - Younas, Farhan
A1  - Mafakheri, Samaneh
A1  - Pothula, Karunakar R.
A1  - Kleinekathöfer, Ulrich
A1  - Tauch, Andreas
A1  - Benz, Roland
T1  - Identification and characterization of smallest pore-forming protein in the cell wall of pathogenic Corynebacterium urealyticum DSM 7109
JF  - BMC Biochemistry
N2  - Background: Corynebacterium urealyticum, a pathogenic, multidrug resistant member of the mycolata, is known as causative agent of urinary tract infections although it is a bacterium of the skin flora. This pathogenic bacterium shares with the mycolata the property of having an unusual cell envelope composition and architecture, typical for the genus Corynebacterium. The cell wall of members of the mycolata contains channel-forming proteins for the uptake of solutes. Results: In this study, we provide novel information on the identification and characterization of a pore-forming protein in the cell wall of C. urealyticum DSM 7109. Detergent extracts of whole C. urealyticum cultures formed in lipid bilayer membranes slightly cation-selective pores with a single-channel conductance of 1.75 nS in 1 M KCl. Experiments with different salts and non-electrolytes suggested that the cell wall pore of C. urealyticum is wide and water-filled and has a diameter of about 1.8 nm. Molecular modelling and dynamics has been performed to obtain a model of the pore. For the search of the gene coding for the cell wall pore of C. urealyticum we looked in the known genome of C. urealyticum for a similar chromosomal localization of the porin gene to known porH and porA genes of other Corynebacterium strains. Three genes are located between the genes coding for GroEL2 and polyphosphate kinase (PKK2). Two of the genes (cur_1714 and cur_1715) were expressed in different constructs in C. glutamicum Delta porA Delta porH and in porin-deficient BL21 DE3 Omp8 E. coli strains. The results suggested that the gene cur_1714 codes alone for the cell wall channel. The cell wall porin of C. urealyticum termed PorACur was purified to homogeneity using different biochemical methods and had an apparent molecular mass of about 4 kDa on tricine-containing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Conclusions: Biophysical characterization of the purified protein (PorACur) suggested indeed that cur_1714 is the gene coding for the pore-forming protein in C. urealyticum because the protein formed in lipid bilayer experiments the same pores as the detergent extract of whole cells. The study is the first report of a cell wall channel in the pathogenic C. urealyticum.
KW  - cell wall channel
KW  - mycolic acid
KW  - porin
KW  - Corynebacterium urealyticum
KW  - lipid bilayer membrane
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226959
VL  - 19
ER  - 
TY  - THES
A1  - Abdel Rahman, Faisal Mirghani
T1  - Systematic analysis of genes expressed in the retinal pigment epithelium (RPE) and identification of candidates for genetic susceptibility to age-related macular degeneration (AMD)
N2  - Age related macular degeneration (AMD) is the leading cause of visual impairment in the elderly and the major cause of blindness in the developed world. To date, the molecular mechanisms underlying the disease are not well understood although in recent years a primary involvement of the retinal pigment epithelium (RPE) has become evident. The aim of the present study is to systematically analyse genes which are differentially expressed in the RPE, and to assess their possible association with mechanisms and pathways likely to be related to retinal disease, in particular AMD. Towards this goal, 2379 expressed sequence tags (ESTs) were established from an inhouse generated RPE cDNA library. This library was constructed by using the suppression subtraction hybridization (SSH) technique which normalises redundant sequences and ensures enrichment of rare transcripts. In a first phase, 1002 ESTs were sequenced and subjected to comprehensive alignment with public nucleotide and protein databases. A search of the 1002 ESTs against the human genome draft sequence yielded 168 known genes, 51 predicted genes, 15 unknown transcripts and 41 clones with no significant similarity. Reverse Northern blot hybridization was performed for 318 EST clusters to identify abundantly expressed genes in the RPE and to prioritize subsequent analyses. Representative clones were spotted onto a nylon membrane and hybridized with cDNA probes of driver (heart and liver) and tester (RPE) used in the cDNA library construction. Subsequently, 107 EST clusters were subjected to Northern blot hybridizations. These analyses identified 7 RPE-specific, 3 retina-specific, 7 RPE/retina-specific, and 7 tissue restricted transcripts, while 29 EST clusters were ubiquitously expressed, and evaluation was not possible for another 54 EST clusters. Of the 24 transcripts with specific or restricted expression, 16 clones were selected for further characterization. The predicted gene MGC2477 and 2 novel isoforms of the human transient receptor potential cation channel, subfamily M, member 3 (TRPM3) were cloned and further described in detail. In addition, polymorphic variations for these 2 genes as well as for the human MT-Protocadherin gene were determined. For MGC2477, 15 single nucleotide polymorphisms (SNPs) were identified, with 13 having a frequency of the minor allele greater than 20%. 10 of the 15 SNPs have not been reported in so far in public SNP repertoires. Partial assessment of the TRPM3 gene yielded 35 SNPs. Of these, 30 (85.7%) were highly frequent (0.17-0.5%), and 14 (40%) were novel. The MT-Protocadherin gene revealed 35 SNPs, including 28 (80%) with high frequency of the minor allele. 23 (65.7%) were novel SNPs. These SNPs will be used to construct the most common haplotypes. These will be used in case/control association studies in 400 AMD patients and 200 ethnically and aged matched controls to assess a possible contribution of these genes in the etiology of AMD.
N2  - Die altersabhängige Makuladegeneration (AMD) ist die häufigste Ursache von gravierenden Einschränkungen des Sehvermögens im fortgeschrittenen Lebensalter. In den Industriestaaten ist die AMD zudem die Hauptursache für Altersblindheit. Die molekularen Mechanismen, die zur Entstehung der AMD führen, sind bisher nur unzureichend bekannt. In den letzten Jahren hat es sich jedoch herausgestellt, dass das retinale Pigmentepithel (RPE) eine primäre Rolle in der Pathogenese der AMD spielt. Ziel dieser Arbeit war die systematische Analyse von Genen, welche im RPE differentiell exprimiert werden. Entsprechende Kandidatengene sollten auf deren mögliche Beteiligung an der Entstehung von Erkrankungen der Retina, insbesondere der AMD, untersucht werden. Zunächst wurden 2379 ESTs aus einer innerhalb der Arbeitsgruppe generierten RPE cDNA Bibliothek definiert. Die dazu verwendete cDNA Bibliothek wurde durch die Suppressions- Subtraktions Hybridisierungs-Technik (SSH) konstruiert. Diese Technik gestattet eine Normalisierung gegenüber redundanten Sequenzen und begünstigt gleichzeitig die Anreicherung von seltenen Transkripten. In einer ersten Phase wurden 1002 ESTs sequenziert und einer umfassenden bioinformatischen Analyse mit Hilfe der verfügbaren DNA- und Protein Datenbanken unterzogen. Der Vergleich der 1002 ESTs mit der Draft Sequenz des menschlichen Genoms ergab den Hinweis auf 168 bereits bekannte Gene, 51 mögliche Gene, 15 völlig unbekannte Transkripte und 41 nicht weiter zuordenbare cDNA Klone. 318 EST Cluster wurden einer reversen Northen-Blot Analyse unterzogen um hochexprimierte Gene zu identifizieren und damit Prioritäten für die weiteren Analysen zu setzen. Im Rahmen der Northern-Analyse wurden repräsentative Klone von 107 EST-Klustern mit cDNA Sonden der ursprünglichen cDNA-Bibliothek hybridisiert. Als Ergebnis dieser Analyse fanden sich 7 RPE-spezifische, 3 Retina-spezifische, 7 sowohl RPE- als auch Retinaspezifische sowie 7 auf einzelne Gewebe limitierte Transkripte. 29 EST Cluster erwiesen sich als ubiquitär exprimiert, und 54 Kluster konnten nicht näher zugeordnet werden. Von den 24 Transkripten mit spezifischer oder zumindest begrenzter Expression wurden 16 Klone zur weiteren Charakterisierung ausgewählt. Aus diesen Material wurden im Rahmen dieser Arbeit das Kandidatengen MGC2477 sowie 2 neue Isoformen des menschlichen TRPM3-Gens kloniert und näher charakterisiert. Weiterhin wurden polymorphe Varianten dieser beiden Isoformen und des menschlichen MTProtocadherin- Gens definiert. Im Gen MGC2477 wurden 15 SNPs identifiziert, wovon die Allelhäufigkeit des selteneren Allels bei 13 der SNPs über 20% lag. Für 10 der insgesamt 15 vii SNPs dieses Gens fanden sich bisher keine Einträge in den entprechenden Datenbanken. Die SNP-Suche wurde auch für das TRPM3-Gen durchgeführt und ergab 35 SNPs, wovon 30 (85,7%) als hochfrequent eingestuft werden konnten. 14 dieser 35 SNPs waren bisher nicht in den Datenbanken verzeichnet. Beim MT-Protocadherin-Gen fanden sich ebenfalls 35 SNPs, wobei 80% eine hohe Frequenz des selteneren Allels aufwiesen. In diesem Fall handelte es sich bei 23 der insgesamt 35 SNPs um bisher unbekannte Allele. Diese SNPs bilden den Ausgangspunkt zur Konstruktion der häufigsten Haplotypen der genannten Gene. Mit der Charakterisierung der Einzel-Nukleotid Polymorphismen der Kandidatengene wurde die Grundlage zur Durchführung von Fall/Kontrollstudien gelegt, in deren Rahmen die Bedeutung der jeweiligen Kandidatengene in der Pathogense der AMD untersucht werden kann.
KW  - Senile Makuladegeneration / Pigmentepithel / Genexpression
KW  - RPE
KW  - AMD
KW  - RPE specific genes
Y1  - 2003
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-7053
ER  - 
TY  - JOUR
A1  - Abdel-Latif, Rania
A1  - Fathy, Moustafa
A1  - Anwar, Hend Ali
A1  - Naseem, Muhammad
A1  - Dandekar, Thomas
A1  - Othman, Eman M.
T1  - Cisplatin-induced reproductive toxicity and oxidative stress: ameliorative effect of kinetin
JF  - Antioxidants
N2  - Cisplatin is a commonly used chemotherapeutic agent; however, its potential side effects, including gonadotoxicity and infertility, are a critical problem. Oxidative stress has been implicated in the pathogenesis of cisplatin-induced testicular dysfunction. We investigated whether kinetin use at different concentrations could alleviate gonadal injury associated with cisplatin treatment, with an exploration of the involvement of its antioxidant capacity. Kinetin was administered in different doses of 0.25, 0.5, and 1 mg/kg, alone or along with cisplatin for 10 days. Cisplatin toxicity was induced via a single IP dose of 7 mg/kg on day four. In a dose-dependent manner, concomitant administration of kinetin with cisplatin significantly restored testicular oxidative stress parameters, corrected the distorted sperm quality parameters and histopathological changes, enhanced levels of serum testosterone and testicular StAR protein expression, as well as reduced the up-regulation of testicular TNF-α, IL-1β, Il-6, and caspase-3, caused by cisplatin. It is worth noting that the testicular protective effect of the highest kinetin dose was comparable/more potent and significantly higher than the effects of vitamin C and the lowest kinetin dose, respectively. Overall, these data indicate that kinetin may offer a promising approach for alleviating cisplatin-induced reproductive toxicity and organ damage, via ameliorating oxidative stress and reducing inflammation and apoptosis.
KW  - cytokinins
KW  - kinetin
KW  - cisplatin
KW  - reproductive toxicity
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-271223
SN  - 2076-3921
VL  - 11
IS  - 5
ER  - 
TY  - JOUR
A1  - Abdelhafez, Omnia Hesham
A1  - Fawzy, Michael Atef
A1  - Fahim, John Refaat
A1  - Desoukey, Samar Yehia
A1  - Krischke, Markus
A1  - Mueller, Martin J.
A1  - Abdelmohsen, Usama Ramadan
T1  - Hepatoprotective potential of Malvaviscus arboreus against carbon tetrachloride-induced liver injury in rats
JF  - PLoS ONE
N2  - Malvaviscus arboreus Cav. is a medicinal plant belonging to family Malvaceae with both ethnomedical and culinary value; however, its phytochemical and biological profiles have been scarcely studied. Accordingly, this work was designed to explore the chemical composition and the hepatoprotective potential of M. arboreus against carbon tetrachloride (CCl\(_4\))-induced hepatotoxicity. The total extract of the aerial parts and its derived fractions (petroleum ether, dichloromethane, ethyl acetate, and aqueous) were orally administered to rats for six consecutive days, followed by injection of CCl\(_4\) (1:1 v/v, in olive oil, 1.5 ml/kg, i.p.) on the next day. Results showed that the ethyl acetate and dichloromethane fractions significantly alleviated liver injury in rats as indicated by the reduced levels of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total bilirubin (TB), and malondialdehyde (MDA), along with enhancement of the total antioxidant capacities of their livers, with the maximum effects were recorded by the ethyl acetate fraction. Moreover, the protective actions of both fractions were comparable to those of silymarin (100 mg/kg), and have been also substantiated by histopathological evaluations. On the other hand, liquid chromatography-high resolution electrospray ionization mass spectrometry (LC‒HR‒ESI‒MS) metabolomic profiling of the crude extract of M. arboreus aerial parts showed the presence of a variety of phytochemicals, mostly phenolics, whereas the detailed chemical analysis of the most active fraction (i.e. ethyl acetate) resulted in the isolation and identification of six compounds for the first time in the genus, comprising four phenolic acids; β-resorcylic, caffeic, protocatechuic, and 4-hydroxyphenylacetic acids, in addition to two flavonoids; trifolin and astragalin. Such phenolic principles, together with their probable synergistic antioxidant and liver-protecting properties, seem to contribute to the observed hepatoprotective potential of M. arboreus.
KW  - high performance liquid chromatography
KW  - phenols
KW  - phytochemicals
KW  - antioxidants
KW  - metabolomics
KW  - medicinal plants
KW  - Egypt
KW  - xenobiotic metabolism
KW  - Malvaviscus arboreus
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177243
VL  - 13
IS  - 8
ER  - 
TY  - JOUR
A1  - Abdelhameed, Reda F. A.
A1  - Eltamany, Enas E.
A1  - Hal, Dina M.
A1  - Ibrahim, Amany K.
A1  - AboulMagd, Asmaa M.
A1  - Al-Warhi, Tarfah
A1  - Youssif, Khayrya A.
A1  - Abd El-kader, Adel M.
A1  - Hassanean, Hashim A.
A1  - Fayez, Shaimaa
A1  - Bringmann, Gerhard
A1  - Ahmed, Safwat A.
A1  - Abdelmohsen, Usama Ramadan
T1  - New cytotoxic cerebrosides from the Red Sea cucumber Holothuria spinifera supported by in-silico studies
JF  - Marine Drugs
N2  - Bioactivity-guided fractionation of a methanolic extract of the Red Sea cucumber Holothuria spinifera and LC-HRESIMS-assisted dereplication resulted in the isolation of four compounds, three new cerebrosides, spiniferosides A (1), B (2), and C (3), and cholesterol sulfate (4). The chemical structures of the isolated compounds were established on the basis of their 1D NMR and HRMS spectral data. Metabolic profiling of the H. spinifera extract indicated the presence of diverse secondary metabolites, mostly hydroxy fatty acids, diterpenes, triterpenes, and cerebrosides. The isolated compounds were tested for their in vitro cytotoxicities against the breast adenocarcinoma MCF-7 cell line. Compounds 1, 2, 3, and 4 displayed promising cytotoxic activities against MCF-7 cells, with IC\(_{50}\) values of 13.83, 8.13, 8.27, and 35.56 µM, respectively, compared to that of the standard drug doxorubicin (IC\(_{50}\) 8.64 µM). Additionally, docking studies were performed for compounds 1, 2, 3, and 4 to elucidate their binding interactions with the active site of the SET protein, an inhibitor of protein phosphatase 2A (PP2A), which could explain their cytotoxic activity. This study highlights the important role of these metabolites in the defense mechanism of the sea cucumber against fouling organisms and the potential uses of these active molecules in the design of new anticancer agents.
KW  - LC-HRESIMS
KW  - Holothuria spinifera
KW  - cerebrosides
KW  - molecular docking
KW  - cytotoxicity
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211089
SN  - 1660-3397
VL  - 18
IS  - 8
ER  - 
TY  - JOUR
A1  - Abdelhameed, Reda F. A.
A1  - Habib, Eman S.
A1  - Eltahawy, Nermeen A.
A1  - Hassanean, Hashim A.
A1  - Ibrahim, Amany K.
A1  - Mohammed, Anber F.
A1  - Fayez, Shaimaa
A1  - Hayallah, Alaa M.
A1  - Yamada, Koji
A1  - Behery, Fathy A.
A1  - Al-Sanea, Mohammad M.
A1  - Alzarea, Sami I.
A1  - Bringmann, Gerhard
A1  - Ahmed, Safwat A.
A1  - Abdelmohsen, Usama Ramadan
T1  - New cytotoxic natural products from the Red Sea sponge Stylissa carteri
JF  - Marine Drugs
N2  - Bioactivity-guided isolation supported by LC-HRESIMS metabolic profiling led to the isolation of two new compounds, a ceramide, stylissamide A (1), and a cerebroside, stylissoside A (2), from the methanol extract of the Red Sea sponge Stylissa carteri. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The bioactive extract’s metabolomic profiling showed the existence of various secondary metabolites, mainly oleanane-type saponins, phenolic diterpenes, and lupane triterpenes. The in vitro cytotoxic activity of the isolated compounds was tested against two human cancer cell lines, MCF-7 and HepG2. Both compounds, 1 and 2, displayed strong cytotoxicity against the MCF-7 cell line, with IC\(_{50}\) values at 21.1 ± 0.17 µM and 27.5 ± 0.18 µM, respectively. They likewise showed a promising activity against HepG2 with IC\(_{50}\) at 36.8 ± 0.16 µM for 1 and IC\(_{50}\) 30.5 ± 0.23 µM for 2 compared to the standard drug cisplatin. Molecular docking experiments showed that 1 and 2 displayed high affinity to the SET protein and to inhibitor 2 of protein phosphatase 2A (I2PP2A), which could be a possible mechanism for their cytotoxic activity. This paper spreads light on the role of these metabolites in holding fouling organisms away from the outer surface of the sponge, and the potential use of these defensive molecules in the production of novel anticancer agents.
KW  - LC-HRESIMS
KW  - Stylissa carteri
KW  - ceramide
KW  - cerebroside
KW  - docking
KW  - cytotoxic activity
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-205795
SN  - 1660-3397
VL  - 18
IS  - 5
ER  - 
TY  - JOUR
A1  - Abdelhameed, Reda F. A.
A1  - Habib, Eman S.
A1  - Goda, Marwa S.
A1  - Fahim, John Refaat
A1  - Hassanean, Hashem A.
A1  - Eltamany, Enas E.
A1  - Ibrahim, Amany K.
A1  - AboulMagd, Asmaa M.
A1  - Fayez, Shaimaa
A1  - Abd El-kader, Adel M.
A1  - Al-Warhi, Tarfah
A1  - Bringmann, Gerhard
A1  - Ahmed, Safwat A.
A1  - Abdelmohsen, Usama Ramadan
T1  - Thalassosterol, a New Cytotoxic Aromatase Inhibitor Ergosterol Derivative from the Red Sea Seagrass Thalassodendron ciliatum
JF  - Marine Drugs
N2  - Thalassodendron ciliatum (Forssk.) Den Hartog is a seagrass belonging to the plant family Cymodoceaceae with ubiquitous phytoconstituents and important pharmacological potential, including antioxidant, antiviral, and cytotoxic activities. In this work, a new ergosterol derivative named thalassosterol (1) was isolated from the methanolic extract of T. ciliatum growing in the Red Sea, along with two known first-reported sterols, namely ergosterol (2) and stigmasterol (3), using different chromatographic techniques. The structure of the new compound was established based on 1D and 2D NMR spectroscopy and high-resolution mass spectrometry (HR-MS) and by comparison with the literature data. The new ergosterol derivative showed significant in vitro antiproliferative potential against the human cervical cancer cell line (HeLa) and human breast cancer (MCF-7) cell lines, with IC\(_{50}\) values of 8.12 and 14.24 µM, respectively. In addition, docking studies on the new sterol 1 explained the possible binding interactions with an aromatase enzyme; this inhibition is beneficial in both cervical and breast cancer therapy. A metabolic analysis of the crude extract of T. ciliatum using liquid chromatography combined with high-resolution electrospray ionization mass spectrometry (LC-ESI-HR-MS) revealed the presence of an array of phenolic compounds, sterols and ceramides, as well as di- and triglycerides.
KW  - cytotoxic activity
KW  - ergosterol derivative
KW  - metabolic analysis
KW  - docking studies
KW  - seagrass
KW  - Thalassodendron ciliatum
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236085
VL  - 18
IS  - 7
ER  - 
TY  - THES
A1  - Abdelmohsen, Usama Ramadan
T1  - Antimicrobial Activities from Plant Cell Cultures and Marine Sponge-Associated Actinomycetes
T1  - Antimikrobielle Aktivitäten aus Pflanzenzellkulturen und marinen Schwamm-assoziierten Actinomyceten
N2  - This thesis is divided into three parts with the main goal allocating novel antimicrobial compounds that could be used as future antibiotics. The first part aimed to evaluate the potential of plant suspension cultures for the production of antimicrobial proteins. The extracellular, intracellular and cell wall bound fractions of seven heterotrophic and photomixotrophic plant cell suspension cultures treated with nine different elicitors were tested for the elicitor dependent production of antimicrobial proteins. Bioactivities were tested against a selected panel of human isolates including Gram-positive and Gram-negative bacteria as well as fungi using the disc diffusion assay. The intracellular fractions of elicited cell cultures were more active than extracellular fractions while the cell wall bound fractions showed lowest activities. Among the 21 fractions tested, the intracellular fraction of Lavendula angustifolia elicited with DC3000 was most active against Candida maltosa. The second most active fraction was the intracellular fraction of Arabidopsis thaliana elicited with salicylic acid which was moreover active against all test strains. The antimicrobial activity of elicited Arabidopsis thaliana cell cultures was tested by bioautography to locate the antimicrobial proteins in the crude extract. The intracellular fraction of photomixotrophic Arabidopsis thaliana cells elicited with salicylic acid was selected for further gel filtration chromatography on S-200 column leading to the purification of one 19 kDa antimicrobially active protein, designated, AtAMP. Our findings suggest that elicited plant cell cultures may present a new promising alternative source of antimicrobial proteins. The second part comprises the isolation of actinomycetes associated with marine sponges and testing the bioactivities of new species for further investigations. Actinobacterial communities of eleven taxonomically different sponges that had been collected from offshore Ras Mohamed (Egypt) and from Rovinj (Croatia) were investigated by a culture-based approach using different standard media for isolation of actinomycetes and media enriched with aqueous sponge extract to target rare and new actinomycete species. Phylogenetic characterization of 52 representative isolates out of 90 based on almost complete sequences of genes encoding 16S rRNA supported their assignment to 18 different actinomycete genera. Altogether 14 putatively new species were identified based on sequence similarity values below 98.2% to other strains in the NCBI database. The use of M1 agar amended with aqueous sponge extract yielded a putative new genus related to Rubrobacter which highlighting the need for innovative cultivation protocols. Biological activity testing showed that five isolates were active against Gram-positives only, one isolate was active against Candida albicans only and one isolate showed activity against both groups of pathogens. Moreover, the antiparasistic activity was documented for four isolates. These results showed a high diversity of actinomycetes associated with marine sponges as well as highlighted their potential to produce anti-infective agents. The third part of the thesis focused on the isolation and structure elucidation of new bioactive compounds. Streptomyces strain RV15 recovered from sponge Dysidea tupha, was selected for further chemical analysis by virtue of the fact that it exhibited the greatest antimicrobial potential against Staphylococcus aureus as well as Candida albicans among the all tested strains. Moreover, members of the genus Streptomyces are well known as prolific producers of interesting pharmacologically active metabolites. Chemical analysis of the methanolic crude extract using different chromatographic tools yielded four new compounds. The structures of the new compounds were spectroscopically elucidated to be four new cyclic peptides, namely, cyclodysidins A-D. Their bioactivity was tested against different proteases, bacteria and Candida as well as tumor cell lines. The compounds did not show any significant activities at this point.
N2  - Die hier vorliegende Dissertation ist in drei Kapitel gegliedert und hatte die Bereitstellung neuer antimikrobieller Substanzen, die zukünftig als Antibiotika genutzt werden könnten, zum Hauptziel. Das erste Kapitel befasst sich mit dem Potenzial von Pflanzen zur Produktion von Proteinen mit antimikrobieller Wirkung. Pflanzenzellkulturen wurden mit neun verschiedenen Induktoren stimuliert und anschließend auf die Produktion von Proteinen mit antimikrobieller Wirkung hin untersucht. Dafür wurden die extra-, intrazellulären sowie die membrangebundenen Proteinfraktionen von sieben heterotrophen und photomixotrophen Pflanzenzellkulturen extrahiert. Mittels Diffusionstests wurden die Wirkung der Proteine gegen eine Sammlung menschlicher Pathogene inklusive Gram-positiver und Gram-negativer Bakterien, sowie Pilze getestet. Die intrazellulären Fraktionen zeigten dabei höhere Aktivitäten als die extrazellulären, wohingegen die membrangebundenen Proteine die geringsten Aktivitäten aufwiesen. Von den insgesamt 21 getesteten Proteinfraktionen wies die mit DC3000 induzierte intrazelluläre Fraktion von Lavendula angustifolia die größte Wirkung gegen Candida maltosa auf. Die mit Salicylsäure induzierte intrazelluläre Proteinfraktion von Arabidopsis thaliana zeigte eine Hemmung aller getesteten pathogenen Stämme. Die antimikrobielle Aktivität der induzierten Arabidopsis thaliana-Zellkultur wurde mittels Bioautography weiter untersucht, um das wirksame Protein im Gesamt-(Roh-) extrakt einzugrenzen. Die intrazelluläre Fraktion der photomixotrophen Arabidopsis thaliana-Zellkultur wurde ausgewählt, um ein 19 kDa Protein mit antimikrobieller Wirkung, genannt AtAMP, mittels Gelfitrationschromatography über eine S-200 Säule aufzureinigen. Unsere Ergebnisse weisen darauf hin, dass induzierte Pflanzenzellkulturen zukünftig als aussichtsreiche alternative Quelle für antimikrobiell wirksame Proteine herangezogen werden können. Der zweite Teil dieser Dissertation beinhaltet die Isolation von mit marinen Schwämmen assoziierten Actinomyceten und deren Testung auf Bioaktivität. Aus 11 taxonomisch verschiedenen, an den Küsten von Ras Mohamed (Ägypten) und Rovinj (Kroatien) gesammelten Schwammspezies, wurden Actinobakterien auf verschiedenen Standardmedien kultiviert. Um seltene, neue Stämme zu isolieren, wurden diese Medien mit wässrigen Schwammextrakten angereichert. Die auf der 16S rRNA-Gensequenz basierenden phylogenetischen Charakterisierung von 52 der insgesamt 90 Isolate, zeigte die Zugehörigkeit zu 18 verschiedenen Actinomyceten-Gattungen. Die 16S rRNA-Gene von 14 Isolaten zeigten Homologien von weniger als 98,2% zu denen anderer in Datenbanken abgelegten Bakterien und stellen somit vermutlich neue Arten dar. Die Verwendung von mit Schwammextrakt angereichertem M1-Agar resultierte in der Kultivierung einer mutmaßlich neuen, mit Rubrobacter verwandten Gattung und bestätigt die Notwendigkeit der Entwicklung neuer innovativer Kultivierungsprotokolle. Aktivitätstests von fünf Isolaten zeigten deren hemmende Wirkung nur gegen Gram-positive Bakterien, ein Isolat zeigte Aktivität nur gegen Candida albicans und ein Isolat war wirksam gegen beide genannten Pathogengruppen. Desweiteren konnten antiparasitäre Wirkungen von vier Isolaten dokumentiert werden. Die hier beschriebenen Ergebnisse zeigen die große Diversität von mit Schwämmen assoziierten Actinomyceten und deren Potential Antiinfektiva zu produzieren. Der dritte Teil dieser Arbeit fokussierte sich auf die Isolation und Strukturaufklärung neuer bioaktiver Substanzen. Streptomyceten sind bekannt für die Produktion von interessanten, pharmakologisch aktiven Metaboliten. Der aus dem Schwamm Dysidea tupha isolierte Stamm Streptomyces RV 15 zeigte eine hohe Aktivität gegen Staphylococcus aureus und C. albicans und wurde deshalb für nähere Untersuchungen ausgewählt. Die chemische Analyse des Methanol-Rohextrakts unter der Verwendung verschiedener Chromatographie-Verfahren resultierte in der Isolation von vier Substanzen. Die spektroskopische Analyse zeigte, dass diese neuen Substanzen zyklische Peptidstrukturen aufweisen und wurden daraufhin als Cyclodysidin A-D benannt. Die Bioaktivitäten dieser Substanzen wurden gegen verschiedene Proteasen, Bakterien und Candida sowie gegen verschiedene Tumorzelllinien getestet. Bis zum jetzigen Zeitpunkt zeigte keine der getesteten Peptide eine aussagekräftige Wirkung.
KW  - Antimikrobieller Wirkstoff
KW  - Pflanzenzelle
KW  - Zellkultur
KW  - Antimikrobielle Aktivitäten
KW  - Pflanzenzellkulturen
KW  - Proteinen mit antimikrobieller Wirkung
KW  - Actinomyceten
KW  - zyklische Peptide
KW  - Antimicrobial activities
KW  - Plant cell cultures
KW  - Antimicrobial proteins
KW  - Actinomycetes
KW  - Cyclic peptides
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-51483
ER  - 
TY  - JOUR
A1  - Abdelmohsen, Usama Ramadan
A1  - Cheng, Cheng
A1  - Viegelmann, Christina
A1  - Zhang, Tong
A1  - Grkovic, Tanja
A1  - Ahmed, Safwat
A1  - Quinn, Ronald J.
A1  - Hentschel, Ute
A1  - Edrada-Ebel, RuAngelie
T1  - Dereplication Strategies for Targeted Isolation of New Antitrypanosomal Actinosporins A and B from a Marine Sponge Associated-Actinokineospora sp EG49
JF  - Marine Drugs
N2  - High resolution Fourier transform mass spectrometry (HRFTMS) and nuclear magnetic resonance (NMR) spectroscopy were employed as complementary metabolomic tools to dereplicate the chemical profile of the new and antitrypanosomally active sponge-associated bacterium Actinokineospora sp. EG49 extract. Principal Component (PCA), hierarchical clustering (HCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) were used to evaluate the HRFTMS and NMR data of crude extracts from four different fermentation approaches. Statistical analysis identified the best culture one-strain-many-compounds (OSMAC) condition and extraction procedure, which was used for the isolation of novel bioactive metabolites. As a result, two new O-glycosylated angucyclines, named actinosporins A (1) and B (2), were isolated from the broth culture of Actinokineospora sp. strain EG49, which was cultivated from the Red Sea sponge Spheciospongia vagabunda. The structures of actinosporins A and B were determined by 1D- and 2D-NMR techniques, as well as high resolution tandem mass spectrometry. Testing for antiparasitic properties showed that actinosporin A exhibited activity against Trypanosoma brucei brucei with an IC₅₀ value of 15 µM; however no activity was detected against Leishmania major and Plasmodium falciparum, therefore suggesting its selectivity against the parasite Trypanosoma brucei brucei; the causative agent of sleeping sickness.
KW  - dereplication
KW  - secondary metabolomics
KW  - anti-trypanosoma
KW  - Actinokineospora
KW  - Spheciospongia vagabunda
KW  - actinosporins
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119876
SN  - 1660-3397
VL  - 12
IS  - 3
ER  - 
TY  - JOUR
A1  - Abdelmohsen, Usama Ramadan
A1  - Pimentel-Elardo, Sheila M.
A1  - Hanora, Amro
A1  - Radwan, Mona
A1  - Abou-El-Ela, Soad H.
A1  - Ahmed, Safwat
A1  - Hentschel, Ute
T1  - Isolation, Phylogenetic Analysis and Anti-infective Activity Screening of Marine Sponge-Associated Actinomycetes
N2  - Terrestrial actinomycetes are noteworthy producers of a multitude of antibiotics, however the marine representatives are much less studied in this regard. In this study, 90 actinomycetes were isolated from 11 different species of marine sponges that had been collected from offshore Ras Mohamed (Egypt) and from Rovinj (Croatia). Phylogenetic characterization of the isolates based on 16S rRNA gene sequencing supported their assignment to 18 different actinomycete genera representing seven different suborders. Fourteen putatively novel species were identified based on sequence similarity values below 98.2% to other strains in the NCBI database. A putative new genus related to Rubrobacter was isolated on M1 agar that had been amended with sponge extract, thus highlighting the need for innovative cultivation protocols. Testing for anti-infective activities was performed against clinically relevant, Gram-positive (Enterococcus faecalis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, fungi (Candida albicans) and human parasites (Leishmania major, Trypanosoma brucei). Bioactivities against these pathogens were documented for 10 actinomycete isolates. These results show a high diversity of actinomycetes associated with marine sponges as well as highlight their potential to produce anti-infective agents.
KW  - Biologie
KW  - actinomycetes
KW  - marine sponges
KW  - anti-infective
KW  - anti-parasitic
KW  - phylogenetic
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68307
ER  -