Benzoxacystol, a benzoxazine-type enzyme inhibitor from the deep-sea strain Streptomyces sp. NTK 935.

Benzoxacystol, a new 1,4-benzoxazine-type metabolite, was produced by strain NTK 935, a marine member of the Streptomyces griseus 16S rRNA clade, isolated from deep-sea sediment collected from the Canary Basin. The structure of benzoxacystol was determined by mass spectrometry, NMR experiments and X-ray analysis. The compound showed an inhibitory activity against the enzyme glycogen synthase kinase 3β and a weak antiproliferative activity against mouse fibroblast cells.

Caboxamycin, a new antibiotic of the benzoxazole family produced by the deep-sea strain Streptomyces sp. NTK 937.

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.

Albidopyrone, a new alpha-pyrone-containing metabolite from marine-derived Streptomyces sp. NTK 227.

Albidopyrone, a new alpha-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.

Proximicin A, B and C, novel aminofuran antibiotic and anticancer compounds isolated from marine strains of the actinomycete Verrucosispora.

A family of three novel aminofuran antibiotics named as proximicins was isolated from the marine Verrucosispora strain MG-37. Proximicin A was detected in parallel in the marine abyssomicin producer "Verrucosispora maris" AB-18-032. The characteristic structural element of proximicins is 4-amino-furan-2-carboxylic acid, a hitherto unknown gamma-amino acid.

Frigocyclinone, a novel angucyclinone antibiotic produced by a Streptomyces griseus strain from Antarctica.

A new angucyclinone antibiotic, frigocyclinone, was isolated from Streptomyces griseus strain NTK 97, consisting of a tetrangomycin moiety attached through a C-glycosidic linkage with the aminodeoxysugar ossamine. Frigocyclinone showed antibacterial activities against Gram-positive bacteria.

Marine actinomycetes as a source of novel secondary metabolites.

A set of 600 actinomycetes strains which were isolated from marine sediments from various sites in the Pacific and Atlantic Oceans were screened for the production of bioactive secondary metabolites. Marine streptomycete strains were found to be producers of well known chemically diverse antibiotics isolated from terrestrial streptomycetes, as in the case of marine Micromonospora strains. New marine members of the rare genus Verrucosispora seem to be a promising source for novel bioactive secondary metabolites as shown in the case of the abyssomicin producing strain AB-18-032.