Mariana Kolarova

Microbiaeratin, a new natural indole alkaloid from a Microbispora aerata strain, isolated from Livingston Island, Antarctica.

Abstract A new sulphur‐containing natural alkaloid named microbiaeratin (1a) was isolated, together with the known microbiaeratinin (2, bacillamide) from the culture filtrate of Microbispora aerata strain IMBAS‐11A. The organism was isolated from penguin excrements collected on the Antarctic Livingston Island. The structure was elucidated by one‐ and two‐dimensional NMR experiments and mass spectrometric investigations.

Diphenylether and Macrotriolides Occurring in a Fungal Isolate from the Antarctic Lichen Neuropogon

Abstract The fungus, Tritirachium sp. HKI 0317, was isolated from the Antarctic lichen Neuropogon sp. Fermentation of this strain, extraction of the culture broth, and preparative separation of produced compounds furnished 4‐carboxy‐5,5′‐dihydroxy‐3,3′‐dimethyldiphenylether (1), macrosphelide A (2), and macrosphelide J (3). The structures were elucidated on the basis of MS and NMR measurements, and the previously published data for this compounds.

Structure elucidation of a new natural diketopiperazine from a Microbispora aerata strain isolated from Livingston Island, Antarctica

A new natural diketopiperazine (1) was obtained from the culture broth of Microbispora aerata strain imbas-11A, isolated from penguin excrements collected on the Antarctic Livingston Island. Compound 1 was purified consecutively by solvent extraction, silica gel column chromatography and preparative HPLC. The structure of the compound was elucidated by 1D and 2D NMR experiments and mass spectrometric investigations. The absolute configuration of compound 1 was determined by amino acid analysis and NOESY correlations. A low antiproliferative and cytotoxic effect of trans-cyclo-(D-tryptophanyl-L-tyrosyl) (1) was determined with L-929 mouse fibroblast cells, K-562 human leukemia cells and HeLa human cervix carcinoma. Trans-cyclo-(D-tryptophanyl-L-tyrosyl) (1) did not show antimicrobial activity at a concentration of 50 µg per disc against Bacillus subtilis, Staphylococcus aureus, Streptomyces viridochromogenes, Escherichia coli, Candida albicans and Mucor miehei.

ISOLATION AND STRUCTURE ELUCIDATION OF TYRAMINE AND INDOLE ALKALOIDS FROM ANTARCTIC STRAIN MICROBISPORA AERATA IMBAS-11A

ABSTRACT The tyramine alkaloids as a N-acetyltyramine (C10H13NO2, MW.179), N-acetyl-3-(phydroxyphenyl)-propylamine (C11H15NO2, MW.193) and the indole alkaloid L, L-cyclo(tryptophanylprolyl) (C16H17N3O2, MW.283) were isolated from the culture broth of Microbispora aerata subsp.nov.IMBAS-11A. The strain was isolated from penguin excrements collected on the Antarctic Livingstone Island. The structures of the metabolites were settled on the basis of mass spectrometry, 1D and 2D NMR spectroscopy.

Sanionins: Anti‐Inflammatory and Antibacterial Agents with Weak Cytotoxicity from the Antarctic Moss Sanionia georgico‐uncinata

Abstract Sanionins A (1) and B (2) were isolated from the moss Sanionia georgico‐uncinata, collected on the Antarctic Livingston Island. The compounds 1 and 2 were purified by solvent extraction, silica gel column chromatography, and preparative HPLC, consecutively. The structures of the both compounds were elucidated by 1D and 2D NMR experiments and mass spectrometric investigations. These compounds showed activity against important Gram‐positive pathogens, such as mycobacteria, multiresistant staphylococci, and vancomycin resistant enterococci. This activity is combined with antiinflammatoric activity and low cytotoxicity.

Isolation and Characterization of a Psychrotolerant Streptomyces Strain from Permafrost Soil in Spitsbergen, Producing Phthalic Acid Ester

ABSTRACT An actinomycete, strain SB9, was isolated from a soil sample collected from permafrost in Spitsbergen, Arctic Ocean. The strain is psychrotolerant with growth at temperatures between 4°C and 30°C and optimal growth temperature between 20°C and 28°C. Phylogenetic analysis of the 16S rRNA gene sequence of the strain SB9 indicated a high level of sequence similarity (99%) to Streptomyces avidinii. The 16S rRNA gene sequence data of strain SB9 have been deposited in the GenBank databases under the accession number EU878377. The strain produces di-(2-ethylhexyl) phthalate (DEHP). The identification of (DEHP) was settled on the basis of electrospray mass spectrometry (ESI-MS), 1D NMR spectroscopy, and comparison with standards. Isolated compound showed antimicrobial activity against various microorganisms.

STRUCTURAL ELUCIDATION OF A BIOACTIVE METABOLITES PRODUCED BY STREPTOMYCES AVIDINII SB9 STRAIN, ISOLATED FROM PERMAFROST SOIL IN SPITSBERGEN, ARCTIC

ABSTRACT Streptomyces avidinii strain SB9 was isolated from permafrost soil samples in Spitsbergen, Arctic Ocean. The strain is psychrotolerant with optimal growth temperature between 20°C and 28°C. During our continuous search for unique secondary metabolites, we have investigated an arctic isolate of Streptomyces avidinii SB9 and we found for the first time, that Sreptomyces avidinii strain SB9 produces 2-amino-3-dodecanol [1], norophthalmic acid (2S)-2-amino-4-[[(1S)-1-(carboxymethylcarbamoyl) ethyl]carbamoyl] butanoic acid [2] and phthalic acid ester [3]. The compounds were purified by solvent extraction, silica gel column chromatography and preparative TLC consecutively. The structures of the compounds were elucidated by NMR experiments and mass spectrometric investigations. These compounds showed antimicrobial activity against important Gram-positive bacteria and fungi. Our studies are motivated by an interest in the functional role played by natural products in the ecological interactions of the strain with other members of the microbial community.

Malonyl-4,5-dihydroniphimycin: A New Polyol Macrolide Antibiotic, Produced by Streptomyces hygroscopicus

Malonyl-4,5-dihydroniphimycin was isolated as a new antibiotic from the mycelium of Streptomyces hygroscopicus 15. The chemical constitution was elucidated from the physico-chemical properties, using NMR techniques and mass spectrometry, to be a 36-membered macrolide related to non-polyenic antibiotics. Malonyl-4,5-dihydroniphimycin displays activity against filamentous fungi and Gram-positive bacteria.

Taxonomic Investigations of the Antarctic Mesophilic Strain 2BG, Producer of Secondary Metabolites

ABSTRACT Strain 2BG is an actinomycete isolated from soils during the Antarctic summer collected on the Antarctic Livingstone Island. On the basis of morphological, physiological and biochemical properties the strain has been identified as belonging to species Streptomyces flavus subsp.nov. It produces of secondary metabolites, identical with adenosine, 2 -deoxyadenosine, 2′-deoxythymidine, cyclo(L-Tyrosyl -L -Prolyl) and cyclo (D-Tyrosyl-D-Prolyl).

Usnic Acid, Metabolite from Neuropogon Sp., An Antarctic Lichen Isolation, Structure Elucidation and Biological Activity

ABSTRACT From the lichen Neuropogon sp., collected in the region Livingston Island, Antarctica was isolated secondary metabolite, identical to (-) usnic acid (C18H16O7, MW. 344) with antibiotic activity. The structure was settled on the basis of high-resolution electron impact mass spectrometry(HREI-MS) and one and two dimensional NMR spectroscopy(1H, 13C, DEPT, COSY, HSQC and HMBC). The usnic acid was investigated for antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria as Streptococcus pyogenes 15346, Staphilococcus epidermidis 1093, Bacillus cereus 157, Listeria monocytogenes 981, Yersinia enterocolitica 013, Klebsiella pneumoniae 52145 and Salmonella thyphimurium.