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2014

Presentations of the scientific briefing "New frontiers in Blue Biotechnology - Research and SME Alliances in Early Drug Discovery"

Labes, A. ., & Imhoff, J. F. (2014). Presentations of the scientific briefing "New frontiers in Blue Biotechnology - Research and SME Alliances in Early Drug Discovery". In European Parliament. Abgerufen von http://oceanrep.geomar.de/26366/
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2014

Conference Paper

Antje Labes

Johannes Imhoff
A complete view on the aquatic-derived fungal phylogeny and ecology

Yilmaz, P. ., Glöckner, F. O., Imhoff, J. F., Labes, A. ., Panzer, K. ., Schmaljohann, R. ., … Reich, M. . (2014). A complete view on the aquatic-derived fungal phylogeny and ecology. In 15. International Symposium on Microbiology Ecology. Abgerufen von http://oceanrep.geomar.de/26376/
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2014

Conference Paper

P. Yilmaz

F. Glöckner

Johannes Imhoff

Antje Labes

K. Panzer

Rolf Schmaljohann

M. Weiß

Jutta Wiese

M. Reich
Proteomic analysis of Scopulariopsis brevicaulis LF580 and its mutant strain M26 for the production of the cyclodepsipeptides scopularide A and B

Kramer, A. ., Beck, H. C., Kumar, A. ., Labes, A. ., & Imhoff, J. F. (2014). Proteomic analysis of Scopulariopsis brevicaulis LF580 and its mutant strain M26 for the production of the cyclodepsipeptides scopularide A and B. In 4. Gemeinsame Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) e. V. zusammen mit der Vereinigung für Allgemeine und Angewandte Mikrobiologie (VAAM) e. V. Abgerufen von http://oceanrep.geomar.de/26372/
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2014

Conference Paper

Annemarie Kramer

H. Beck

Abhishek Kumar

Antje Labes

Johannes Imhoff
Bioactive metabolites of a marine Calcarisporium sp.

Silber, J. ., Ohlendorf, B. ., Erhard, A. ., Labes, A. ., & Imhoff, J. F. (2014). Bioactive metabolites of a marine Calcarisporium sp. In ELRIG 2014 Research and Innovation - Impact into Cancer. Abgerufen von http://oceanrep.geomar.de/25551/
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2014

Conference Paper

Johanna Silber

Birgit Ohlendorf

Arlette Erhard

Antje Labes

Johannes Imhoff
Natural products from marine fungi for the treatment of cancer

Imhoff, J. F., & Labes, A. . (2014). Natural products from marine fungi for the treatment of cancer. In 4. Gemeinsame Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) e. V. zusammen mit der Vereinigung für Allgemeine und Angewandte Mikrobiologie (VAAM) e. V. Abgerufen von http://oceanrep.geomar.de/26369/
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2014

Conference Paper

Johannes Imhoff

Antje Labes

2013

Calcarides A?E, Antibacterial Macrocyclic and Linear Polyesters from a Calcarisporium Strain

Silber, J. ., Ohlendorf, B. ., Labes, A. ., Erhard, A. ., & Imhoff, J. F. (2013). Calcarides A?E, Antibacterial Macrocyclic and Linear Polyesters from a Calcarisporium Strain. Marine Drugs, 11, 3309–3323. Abgerufen von http://oceanrep.geomar.de/21998/ (Original work published 2024)

Abstract

Bioactive compounds were detected in crude extracts of the fungus, Calcarisporium sp. KF525, which was isolated from German Wadden Sea water samples. Purification of the metabolites from the extracts yielded the five known polyesters, 15G256\ensuremath\alpha, \ensuremath\alpha-2, \ensuremath\beta, \ensuremath\beta-2 and \ensuremath\pi (1?5), and five new derivatives thereof, named calcarides A?E (6?10). The chemical structures of the isolated compounds were elucidated on the basis of one- and two-dimensional NMR spectroscopy supported by UV and HRESIMS data. The compounds exhibited inhibitory activities against Staphylococcus epidermidis, Xanthomonas campestris and Propionibacterium acnes. As the antibacterial activities were highly specific with regard to compound and test strain, a tight structure-activity relationship is assumed.
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2013

Journal Article

Johanna Silber

Birgit Ohlendorf

Antje Labes

Arlette Erhard

Johannes Imhoff

fungal natural products

Calcarisporium sp.

calcarides A?E

15G256 components

macrocyclic and linear polyesters

antibacterial activities

antibiotic

marine natural products
Calcaripeptides A?C, Cyclodepsipeptides from a Calcarisporium Strain

Silber, J. ., Ohlendorf, B. ., Labes, A. ., Näther, C. ., & Imhoff, J. F. (2013). Calcaripeptides A?C, Cyclodepsipeptides from a Calcarisporium Strain. Journal of Natural Products, 76, 1461–1467. Abgerufen von http://oceanrep.geomar.de/21997/ (Original work published Juli 2013)

Abstract

The isolation and structure elucidation of the novel calcaripeptides A (1), B (2), and C (3) and studies on their biosynthetic origin are described. The calcaripeptides were identified from Calcarisporium sp. strain KF525, which was isolated from the German Wadden Sea. Compounds 1?3 are macrocyclic structures composed of a proline and a phenylalanine residue as well as a nonpeptidic substructure. Structure elucidation was achieved by applying one- and two-dimensional NMR spectroscopy supported by high-resolution mass spectrometry. X-ray crystallography was performed to determine the relative configuration of 1. The absolute configuration of 1 was assigned by HPLC of the amino acids after hydrolysis of the molecule and derivatization with chiral agents. Studies on the biosynthesis by feeding 13C-labeled substrates revealed that the nonpeptidic part of 1 originates from acetate and l-methionine. The involvement of a hybrid between a polyketide synthase and a nonribosomal peptide synthetase in the biosynthesis of the calcaripeptides is discussed.
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2013

Journal Article

Johanna Silber

Birgit Ohlendorf

Antje Labes

Christian Näther

Johannes Imhoff
Higher yields of cyclodepsipetides from Scopulariopsis brevicaulis by random mutagenesis

Paun, L. ., Kramer, A. ., Hihlal, E. ., Labes, A. ., Imhoff, J. F., & Kempken, F. . (2013). Higher yields of cyclodepsipetides from Scopulariopsis brevicaulis by random mutagenesis. In 27. Fungal Genetics Conference. Abgerufen von http://oceanrep.geomar.de/22016/

Abstract

The ascomycete Scopulariopsis brevicaulis, which was isolated from the marine sponge Tethya aurantium, produces two cyclodepsipeptides, scopularides A and B [1]. Both peptides exhibit activity against several tumor cell lines. Within the EU-project MARINE FUNGI (EU FP7, 265926) one of our aims is to enhance the production of these secondary metabolites. We are in the process to establish two ways of random mutagenesis by both UV radiation and transposon-mediated. To this end we created UV-mutants and a miniaturised screening method was developed. UV-radiation was performed at 312 nm and the survival rate was set to 1 \%. With this method a mutant library was established. To screen these mutants for higher secondary metabolites production, we developed a miniaturised screening method which includes decreased cultivation volume, fast extraction and an optimised LC-MS analysis format. Using the UV mutagenesis, we were able to identify several mutants with a higher scopularide production in comparison to the wild type. One of these mutants, which produces three times more biomass and more than double the amount of scopularide A, has been used for another round of mutation. Next generation sequencing is being employed to identify the molecular genetic basis of the observed mutations. In parallel we employ transposable elements to introduce mutants [2]. The impact of transposons on gene expression as well as their ability to cause major mutations within the genome or single genes makes them an interesting tool for random mutagenesis [3, 4, 5]. We employ the Vader transposon in its homologous host and found that Vader mostly integrates within or very close to genes. Thus it appears to be a useful tool for transposon-mediated mutagenesis in A. niger (6). At current we try to enhance its usability by modifying the Vader element.
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2013

Conference Paper

Linda Paun

Annemarie Kramer

ElKbir Hihlal

Antje Labes

Johannes Imhoff

Frank Kempken
Phylogenetic analysis and antibiotic activity of bacteria isolated from the surface of two co-occurring macroalgae from the Baltic Sea

Goecke, F. R., Labes, A. ., Wiese, J. ., & Imhoff, J. F. (2013). Phylogenetic analysis and antibiotic activity of bacteria isolated from the surface of two co-occurring macroalgae from the Baltic Sea. European Journal of Phycology, 48, 47–60. Abgerufen von http://oceanrep.geomar.de/19592/

Abstract

Bacteria associated with Fucus vesiculosus and Delesseria sanguinea, two macroalgae from the Kiel Fjord were investigated seasonally over two years by cultivation-based methods. A total of 166 bacterial strains were isolated from the macroalgae, affiliated to seven classes of bacteria (Actinobacteria, Bacilli, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Cytophagia and Flavobacteria). According to 16S rRNA gene sequence similarities they were arranged in 82 phylotypes of\ensuremath>99.0\% sequence identity. Assuming that chemical factors rule the bacteriamacroalga and bacteriabacteria interactions on algal surfaces, we tested the antibiotic activity of the bacterial isolates not only against a panel of four standard test organisms (Bacillus subtilis, Candida glabrata, Escherichia coli and Staphylococcus lentus) but also four macroalga-associated microorganisms: Algicola bacteriolytica and Pseudoalteromonas elyakovii (macroalgal pathogens), and Bacillus algicola and Formosa algae (strains associated with algal surfaces). Organic extracts of more than 51\% of the isolates from the two macroalgae inhibited the growth of at least one of the tested microorganisms. As much as 46\% and 45\% of the isolates derived from F. vesiculosus and D. sanguinea, respectively, showed antimicrobial activity against the set of macroalga-associated bacteria, compared with 13 and 19\% against a standard set of microorganisms. High antibacterial activity against macroalgal pathogens and bacterial competitors support the assumption that complex chemical interactions shape the relationships of bacteria associated with macroalgae and suggest that these bacteria are a rich source of antimicrobial metabolites.
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2013

Journal Article

Franz Goecke

Antje Labes

Jutta Wiese

Johannes Imhoff

antimicrobial activities

bacterial cultures

chemical associations

Delesseria

epiphytic bacteria

Fucus

Kiel

macroalgabacteria associations
Algae as important environment for bacteria - phylogenetic relationships among species isolated from algae

Goecke, F. R., Thiel, V. ., Wiese, J. ., Labes, A. ., & Imhoff, J. F. (2013). Algae as important environment for bacteria - phylogenetic relationships among species isolated from algae. Phycologia, 52, 14–24. Abgerufen von http://oceanrep.geomar.de/19593/

Abstract

Bacteria are an inherent part of the biotic environment of algae. Recent investigations revealed that bacterial communities associated with algae were generally highly host specific. Several new bacterial species and genera were isolated from algae, which suggested that algae were an interesting environment for discovery of new bacterial taxa; however, the distribution of the different phylogenetic groups among those isolates remained unclear, and this information could help to explain specific associations. We conducted a phylogenetic study based on 16S rRNA gene sequences available in GenBank, including 101 validly described bacterial species that were isolated from eukaryotic macro- and micro-algae from marine and freshwater environments. These species were distributed among six bacterial phyla, including: Bacteroidetes (42 species), Proteobacteria (36 species), and Firmicutes, Actinobacteria, Verrucomicrobia and Planctomycetes (23 species). Bacterial species and strains that carried out similar metabolic functions were found to colonize similar algal taxa or algal groups. This assumption was supported by information available from bacterial species descriptions: (1) Most of the bacteria described from microalgae grouped into the Roseobacter clade (Alphaproteobacteria), which indicated that members of this group were well adapted for life in close association with phytoplankton; and (2) 32\% of the bacterial species, mainly isolates from macroalgae, were able to decompose macroalgal polysaccharides. Because algal-bacterial association are still under-studied in various algal groups, we expect a great number of new bacterial taxa to be discovered in the future.
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2013

Journal Article

Franz Goecke

Vera Thiel

Jutta Wiese

Antje Labes

Johannes Imhoff

Enzyme

Macroalgae

Microbe-alga

Phytoplankton

DINOFLAGELLATE GYMNODINIUM-CATENATUM

MARINE ROSEOBACTER LINEAGE

DISSOLVED ORGANIC-MATTER

IN-SITU HYBRIDIZATION

EPIPHYTIC BACTERIAL

LAMINARIA-JAPONICA

GEN. NOV.

COMMUNITY COMPOSITION

ALEXANDRIUM SPP.

BROWN ALGA

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2014

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