@article{PimentelElardoKozytskaBugnietal.2010,
  author    = {Pimentel-Elardo, Sheila Marie and Kozytska, Svitlana and Bugni, Tim S. and Ireland, Chris M. and Moll, Heidrun and Hentschel, Ute},
  title     = {Anti-Parasitic Compounds from Streptomyces sp. Strains Isolated from Mediterranean Sponges},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68312},
  year      = {2010},
  abstract  = {Actinomycetes are prolific producers of pharmacologically important compounds accounting for about 70\% of the naturally derived antibiotics that are currently in clinical use. In this study, we report on the isolation of Streptomyces sp. strains from Mediterranean sponges, on their secondary metabolite production and on their screening for anti-infective activities. Bioassay-guided isolation and purification yielded three previously known compounds namely, cyclic depsipeptide valinomycin, indolocarbazole alkaloid staurosporine and butenolide. This is the first report of the isolation of valinomycin from a marine source. These compounds exhibited novel anti-parasitic activities specifically against Leishmania major (valinomycin IC50 < 0.11 μM; staurosporine IC50 5.30 μM) and Trypanosoma brucei brucei (valinomycin IC50 0.0032 μM; staurosporine IC50 0.022 μM; butenolide IC50 31.77 μM). These results underscore the potential of marine actinomycetes to produce bioactive compounds as well as the re-evaluation of previously known compounds for novel anti-infective activities.},
  subject      = {Biologie},
  language  = {en}
}
@article{ShadyElHossaryFouadetal.2017,
  author    = {Shady, Nourhan Hisham and El-Hossary, Ebaa M. and Fouad, Mostafa A. and Gulder, Tobias A. M. and Kamel, Mohamed Salah and Abdelmohsen, Usama Ramadan},
  title     = {Bioactive natural products of marine sponges from the Genus Hyrtios},
  series = {Molecules},
  volume    = {22},
  journal   = {Molecules},
  number    = {5},
  doi       = {10.3390/molecules22050781},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158227},
  pages     = {781},
  year      = {2017},
  abstract  = {Marine sponges are known as a rich source for novel bioactive compounds with valuable pharmacological potential. One of the most predominant sponge genera is Hyrtios, reported to have various species such as Hyrtios erectus, Hyrtios reticulatus, Hyrtios gumminae, Hyrtios communis, and Hyrtios tubulatus and a number of undescribed species. Members of the genus Hyrtios are a rich source of natural products with diverse and valuable biological activities, represented by different chemical classes including alkaloids, sesterterpenes and sesquiterpenes. This review covers the literature until June 2016, providing a complete survey of all compounds isolated from the genus Hyrtios with their corresponding biological activities whenever applicable.},
  language  = {en}
}
@article{AbdelmohsenPimentelElardoHanoraetal.2010,
  author    = {Abdelmohsen, Usama Ramadan and Pimentel-Elardo, Sheila M. and Hanora, Amro and Radwan, Mona and Abou-El-Ela, Soad H. and Ahmed, Safwat and Hentschel, Ute},
  title     = {Isolation, Phylogenetic Analysis and Anti-infective Activity Screening of Marine Sponge-Associated Actinomycetes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68307},
  year      = {2010},
  abstract  = {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.},
  subject      = {Biologie},
  language  = {en}
}
@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}
}
@phdthesis{PimentelElardo2008,
  author    = {Pimentel Elardo, Sheila Marie},
  title     = {Novel anti-infective secondary metabolites and biosynthetic gene clusters from actinomycetes associated with marine sponges},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40463},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2008},
  abstract  = {Marine sponges (Porifera) harbor diverse microbial communities within their mesohyl, among them representatives of the phylum Actinobacteria, commonly known as actinomycetes. Actinomycetes are prolific producers of pharmacologically important compounds and are responsible for producing the majority of antibiotics. The main aim of this Ph.D. study was to investigate the metabolic potential of the sponge-associated actinomycetes to produce novel anti-infective agents. The first aim was to cultivate actinomycetes derived from different marine sponges. 16S rDNA sequencing revealed that the strains belonged to diverse actinomycete genera such as Gordonia, Isoptericola, Micromonospora, Nocardiopsis, Saccharopolyspora and Streptomyces. Phylogenetic analyses and polyphasic characterization further revealed that two of these strains represent new species, namely Saccharopolyspora cebuensis strain SPE 10-1T (Pimentel-Elardo et al. 2008a) and Streptomyces axinellae strain Pol001T (Pimentel-Elardo et al. 2008b). Furthermore, secondary metabolite production of the actinomycete strains was investigated. The metabolites were isolated using a bioassay-guided purification scheme followed by structure elucidation using spectroscopic methods and subjected to an elaborate anti-infective screening panel. Several interesting compounds were isolated namely, the novel polyketides cebulactam A1 and A2 (Pimentel-Elardo et al. 2008c), a family of tetromycin compounds including novel derivatives, cyclodepsipeptide valinomycin, indolocarbazole staurosporine, diketopiperazine cycloisoleucylprolyl and butenolide. These compounds exhibited significant anti-parasitic as well as protease inhibitory activities. The third aim of this Ph.D. study was to identify biosynthetic gene clusters encoding for nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) present in the actinomycete strains. Genomic library construction and sequencing revealed insights into the metabolic potential and biosynthetic pathways of selected strains. An interesting NRPS system detected in Streptomyces sp. strain Aer003 was found to be widely distributed in several sponge species, in an ascidian and in seawater and is postulated to encode for a large peptide molecule. Sequencing of the PKS gene cluster of Saccharopolyspora cebuensis strain SPE 10-1T allowed the prediction of the cebulactam biosynthetic pathway which utilizes 3-amino-5-hydroxybenzoic acid as the starter unit followed by successive condensation steps involving methylmalonyl extender units and auxiliary domains responsible for the polyketide assembly. In conclusion, this Ph.D. study has shown that diverse actinomycete genera are associated with marine sponges. The strains, two of them novel species, produced diverse chemical structures with interesting anti-infective properties. Lastly, the presence of biosynthetic gene clusters identified in this study substantiates the biosynthetic potential of actinomycetes to produce exploitable natural products and hopefully provides a sustainable supply of anti-infective compounds.},
  subject      = {Meeresschw{\"a}mme},
  language  = {en}
}