Marco Krämer
University of Bonn
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Publication
Featured researches published by Marco Krämer.
The Journal of Antibiotics | 2009
Claudia Hohmann; Kathrin Schneider; Christina Bruntner; Elisabeth Irran; Graeme Nicholson; Alan T. Bull; Amanda L. Jones; Roselyn Brown; James E. M. Stach; Michael Goodfellow; Winfried Beil; Marco Krämer; Johannes F Imhoff; Roderich D. Süssmuth; Hans-Peter Fiedler
Caboxamycin, a new benzoxazole antibiotic, was detected by HPLC-diode array screening in extracts of the marine strain Streptomyces sp. NTK 937, which was isolated from deep-sea sediment collected in the Canary Basin. The structure of caboxamycin was determined by mass spectrometry, NMR experiments and X-ray analysis. It showed inhibitory activity against Gram-positive bacteria, selected human tumor cell lines and the enzyme phosphodiesterase.
The Journal of Antibiotics | 2009
Claudia Hohmann; Kathrin Schneider; Christina Bruntner; Roselyn Brown; Amanda L. Jones; Michael Goodfellow; Marco Krämer; Johannes F. Imhoff; Graeme Nicholson; Hans-Peter Fiedler; Roderich D. Süssmuth
Albidopyrone, a new α-pyrone-containing secondary metabolite, was produced by Streptomyces sp. NTK 227, a strain isolated from Atlantic Ocean sediment and found to be a member of the Streptomyces albidoflavus 16S rRNA gene clade. The structure of the compound was determined by MS and NMR spectroscopy, and found to have a moderate inhibitory activity against protein-tyrosin phosphatase B.
Archives of Microbiology | 1983
Johannes F. Imhoff; Marco Krämer; Hans G. Trüper
The mechanism of sulfate assimilation was investigated in Rhodopseudomonas sulfidophila, a bacterium able to grow either photoautotrophically, with sulfide as electron donor, or photoheterotrophically with sulfate as sole sulfur source. ATP sulfurylase, adenosine-5′-phosphosulfate kinase, 3′-phosphoadenosine-5′-phosphosulfate sulfotransferase, thiosulfonate reductase and cysteine synthase were present. Reduced sulfur compounds, especially sulfide and sulfite repressed all steps of sulfate activation and reduction including sulfate uptake. Adenosine-5′-phosphosulfate kinase activity in contrast to the other activities was high in the presence of cysteine or reduced glutathione in the growth medium. Sulfur was incorporated into the cellular sulfolipid from sulfate and also from reduced sulfur compounds like cysteine and thiosulfate. The activity of 3′-phosphoadenosine-5′-phosphosulfate sulfotransferase was rapidly lost during gel filtration or dialysis. From comparison with other sulfotransferases and from the specific cofactor requirement for the enzyme of R. sulfidophila it is concluded that two different low molecular weight cofactors are required in this system. A reaction sequence is proposed involving thioredoxin as the reductant of another dialysable low molecular weight cofactor, that binds to the protein.
Labes, Antje, Kajahn, Inga, Krämer, Marco, Stöhr, Rüdiger, Thiel, Vera, Wiese, Jutta and Imhoff, Johannes F. (2008) New natural products from marine microorganisms [Poster] In: European Bioperspectives, 07.-10.10, Hannover. | 2008
Antje Labes; Inga Kajahn; Marco Krämer; Rüdiger Stöhr; Vera Thiel; Jutta Wiese; Johannes F. Imhoff
[Poster] In: XXX. Congreso Chileno de Microbiología, 04.-06.12, Concepción, Chile . | 2008
Andrea Gärtner; Marco Krämer; Inga Kajahn; Antje Labes; Kerstin Nagel; Rüdiger Stöhr; Rolf Schmaljohann; Imke Schneemann; Vera Thiel; Jutta Wiese; Johannes F. Imhoff
[Invited talk] In: European Bioperspectives, 07.10, Hannover . | 2008
Johannes F. Imhoff; Antje Labes; Inga Kajahn; Marco Krämer; Rüdiger Stöhr; Vera Thiel; Jutta Wiese
Wiese, Jutta, Gärtner, Andrea, Heindl, Herwig, Kajahn, Inga, Krämer, Marco, Labes, Antje, Lang, Gerhard, Mitova, M., Nagel, Kerstin, Schmaljohann, Rolf, Schneemann, Imke, Stöhr, Rüdiger, Thiel, Vera, Ju, Z. and Imhoff, Johannes F. (2008) Marine Microbial Resources [Poster] In: 2. Bi-Annual Symposium "The Future Ocean", 06.-09.10, Kiel. | 2008
Jutta Wiese; Andrea Gärtner; Herwig Heindl; Inga Kajahn; Marco Krämer; Antje Labes; Gerhard Lang; Maya I. Mitova; Kerstin Nagel; Rolf Schmaljohann; Imke Schneemann; Rüdiger Stöhr; Vera Thiel; Z. Ju; Johannes F. Imhoff
Krämer, Marco, Thiel, Vera and Imhoff, Johannes F. (2008) Selection of marine D-amino acid utilizing microorganisms: a potential source for novel enzymes [Poster] In: International Congress on Biocatalysis, 31.08.-04.09, Hamburg. | 2008
Marco Krämer; Vera Thiel; Johannes F. Imhoff
[Talk] In: European Bioperspectives, 30.05.-01.06.2007, Köln . | 2007
Marco Krämer; Rüdiger Stöhr; Gerhard Lang; Antje Labes; Rolf Schmaljohann; Jutta Wiese; Johannes F. Imhoff
Krämer, Marco, Stöhr, Rüdiger, Lang, Gerhard, Labes, Antje, Schmaljohann, Rolf, Wiese, Jutta and Imhoff, Johannes F. (2007) New Natural Products from Marine Microorganisms - Zentrum für Marine Wirkstoffe [Talk] In: Neues aus dem Meer (WTSH), 13.06.2007, Büsum. | 2007
Marco Krämer; Rüdiger Stöhr; Gerhard Lang; Antje Labes; Rolf Schmaljohann; Jutta Wiese; Johannes F. Imhoff