[Phylogenetic analysis of bacteria of extreme ecosystems].

Phylogenetic analysis of aerobic chemoorganotrophic bacteria of the two extreme regions (Dead Sea and West Antarctic) was performed on the basis of the nucleotide sequences of the 16S rRNA gene. Thermotolerant and halotolerant spore-forming bacteria 7t1 and 7t3 of terrestrial ecosystems Dead Sea identified as Bacillus licheniformis and B. subtilis subsp. subtilis, respectively. Taking into account remote location of thermotolerant strain 6t1 from closely related strains in the cluster Staphylococcus, 6t1 strain can be regarded as Staphylococcus sp. In terrestrial ecosystems, Galindez Island (Antarctic) detected taxonomically diverse psychrotolerant bacteria. From ornithogenic soil were isolated Micrococcus luteus O-1 and Microbacterium trichothecenolyticum O-3. Strains 4r5, 5r5 and 40r5, isolated from grass and lichens, can be referred to the genus Frondihabitans. These strains are taxonomically and ecologically isolated and on the tree diagram form the joint cluster with three isolates Frondihabitans sp., isolated from the lichen Austrian Alps, and psychrotolerant associated with plants F. cladoniiphilus CafT13(T). Isolates from black lichen in the different stationary observation points on the south side of a vertical cliff identified as: Rhodococcus fascians 181n3, Sporosarcina aquimarina O-7, Staphylococcus sp. 0-10. From orange biofilm of fouling on top of the vertical cliff isolated Arthrobacter sp. 28r5g1, from the moss-- Serratia sp. 6r1g. According to the results, Frondihabitans strains most frequently encountered among chemoorganotrophic aerobic bacteria in the Antarctic phytocenoses.

[Taxonomical status of the psychrotolerant Antarctic microorganisms].

The aerobic chemoorganotrophic bacteria, dominating in soils and phytocenosis of the Antarctic Region, on combination of morphological and biochemical properties belong to several taxons of Bacteria domain. Gram-negative strains 3189, 3415 (fam. Halomonadaceae, Halomonas sp.) and 3088, 3468, 3469 (fam. Moraxellaceae, Psychrobacter sp.) belong to phylum Proteobacteria, to class Gammaproteobacteria. Gram-negative strains 3294 3392 (Rhizobiales, fam. Methylobacteriaceae, Methylobacterium sp.) relate to class Alphaproteobacteria of this phylum. Gram-positive strains 3179, 3275, 3470, 3471 (fam. Microbacteriaceae, Cryobacterium sp.), 3054, 3058, 3411 (fam. Corynebacteriaceae, Corynebacterium sp.) and 3194, 3398 (fam. Micrococcaceae, Micrococcus sp.) relate to phylum Actinobacteria, class Actinobacteria. Thus, the psychrophilic and psychrotolerant Antarctic bacteria (aerobic chemoorganotrophic) isolated from phytocenosis and soils of polar region are characterized by wide taxonomic variety.

[Synthesis of melanin pigments by Antarctic black yeast].

Five strains of the black yeast similar to Exophiala nigra (Nadsoniela nigra), which we have isolated from the Antarctic biotopes, are studied. At cultivation in a periodic operation the maximum level of absolutely dry biomass in five tested strains constituted 3.2-7.8 g/l of medium, melanin pigment yield being 6-9% of absolutely dry mass of cells. Two highly productive strains have been selected. Pigments of the studied black yeast are water-insoluble, however dissolve in alkali and concentrated acids. The maximum absorption of the yeast pigments was in the range of 220 nm. The above-stated properties of pigments of the investigated yeast correspond to the description of melanin fractions of Nadsoniela nigra and some microscopic mushrooms. The water-soluble melanin-pigments have been obtained after the dialysis of alkaline solution of the pigment. UV-spectra and visible absorption spectra of water solution of melanin-pigments are almost identical to those of initial alkaline solutions. It is shown that the studied yeast are resistant to high concentrations of toxic metals (Hg2+, Cu2+, Co2+, Cr(VI) and Ni2+), and introduction of Co2+ into the cultivation medium leads to the increase of pigments synthesis.

[Temperature range for growth of the Antarctic microorganisms].

The assessment of a temperature range for growth of microorganisms isolated at various temperatures (1-5 degrees C or 30 degrees C) from biotopes of the Antarctic region (soil, grass Deschampcia antarctica, grass Colobanthus, a green moss, crustose black lichens and encrustation biofilm on vertical rocks) is made. From 40 to 70% of the investigated Antarctic microorganisms, irrespective of temperature conditions of their isolation, were capable of growing in a wide temperature range (from 1 degrees C to 30 degrees C), i.e. they are psychrotolerant. In selective conditions (1 degrees C or 5 degrees C) the psychrophilic Antarctic bacteria and yeast are isolated which grew in the range from 1 degrees C to 20 degrees C and did not grow at 30 degrees C. At the same time, among the Antarctic microorganisms isolated in nonselective conditions (at 30 degrees C), almost 50% are capable of growing at the lowest temperature (5 degrees C), and a smaller number of strains--at 1 degrees C. However with a decrease of cultivation temperature the growth lag-phase of the Antarctic bacteria increased. Thus the level of the final biomass of the investigated strains did not depend on cultivation temperature. When comparing the temperature range of growth of the mesophilic Antarctic bacteria and collection strains of the same species isolated more than 10 years ago from the region with a temperate climate, the psychrotolerant forms were also revealed among the latter. So, it is shown that the investigated Antarctic bacteria can exist in the temperature range characteristic of terrestrial biotopes of the Antarctic Region (from 1 degrees C to 10 degrees C).

[Resistance of chemoorganotrophic bacteria isolated from Antarctic cliffs to toxic metals].

Resistance to toxic metals ( Hg2+, Cu2+, Ni2+, Co2+, Cr(VI)) of bacteria isolated from rock lichen samples of vertical cliffs located on the biogeographic polygon of Ukrainian Antarctic Station Akademik Vernadsky (island Galindez) is studied. Among the Antarctic rock microorganisms isolated on nonselective medium (without toxic metals), bacteria able to grow at toxic metal concentrations lethal for the majority of microorganisms (Hg2+, Cu2+, Ni2+, Co2+, Cr(VI)) are found out. The studied bacteria are most resistant to Cr(VI) possessing oxidative properties in concentration range 1.25-20.0 g/l depending on the strain. Maximal metal concentrations, at which the growth of bacteria was possible, was: Ni2+ to toxic metals - 2.0 g/l, Co(2+) - 0.1 g/l. In the presence of metal ions possessing both replacing and oxidative properties the strains grew in a concentration range: Hg(2+) - 0.005-0.05 g/l, Cu(2+) - 0.1-1.25 g/l. The highest toxic effect was shown for mercury ions. One of the isolated Antarctic strains which was superresistant to high toxic metal concentrations (g/l): Cr(VI) - 20.0, Ni(2+) - 2.0, Cu(2+) - 1.25, Co(2+) - 0.1, Hg(2+) - 0.05. Thus, for the Antarctic bacteria isolated from rock damaging or bactericidal toxic metal concentrations are by 2-3 orders higher than for the majority of microorganisms.

[Producing of molecular hydrogen by association of sporulating microorganisms].

Technologically promising microbe association, consisting of aerobic and anaerobic sporulating bacteria has been isolated. The association synthesizes molecular hydrogen during fermentation of potato and starch. The association was isolated from soil, pasteurized on the boiling water bath. The association destroys potato during 5-7 days with a decrease of mass up to 17.4 times and synthesizes gas consisting of 60% of H2.

[Microbiological analysis of terrestrial biotopes of the Antarctic region].

Microbiological analysis has been made of 120 samples from biotopes of the western coast of the Antarctic peninsula (Rasmussen cope, Tuxen cope, Waugh mountain), Argentine archipelago islands (Galindez, Skua, Corner, Barchans, Irizar, Uruguay, Cluls, Three Little Pigs, King-George), as well as neighbouring islands (Petermann--on the north, a group of Jalour islands--on the east, Berthelot--on the south-east); and more remote islands (Darboux, Lippmann, Booth). It was found out that the total number of chemoorganotrophic aerobic microorganisms was 10(6) - 10(8) cells/g of soil, that was by 2-3 orders lower than in the regions with temperate climate. One can observe a tendency of decreasing the quantity of chemoorganotrophic microorganisms in the Antartic biotopes (cells/g of a sample) in the following order: soil (1 x 10(7) - 8 x 10(8)), underground part of moss (1 x 10(6) - 5 x 10(7)), grass Deschampsia antarctica (10(6) - 10(8), slit of fresh-water reservoir (10(5) - 10(7)), ground part of moss (10(3) - 10(6)), lichens (10(3) - 10(6)). Representatives of several phylogenetic lines: Proteobacteria (genera Pseudomonas, Methylobacterium, Enterobacter), Firmicutes (genera Bacillus, Staphylococcus), Actinobacteria (genera Brevibacterium, Actinomyces, Streptomyces) have been found in the Antarctic samples. As a rule, genera of bacteria found in the Antarctic Region are widely distributed in different regions of the Earth with temperate climate. Microorganisms similar to the species Exophiala nigra (Issatsch.) Haats et de Hoog 1999, which was first detected 100 years ago by Academician B.L. Isachenko in the Arctic region water, were also isolated from biofilms on vertical rocks of the Galindez Island as well as from the soil of the Irizar Island.