ABSTRACT
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.
Subject(s)
Bacteria, Aerobic/drug effects , Metals, Heavy/toxicity , Antarctic Regions , Autotrophic Processes/physiology , Bacteria, Aerobic/physiology , Cold Temperature , Culture Media , Drug Resistance, Bacterial , Geography , Lichens/microbiology , Microbial Sensitivity Tests , Oxidation-ReductionABSTRACT
The paper deals with the samples of microorganisms isolated from biofilms of encrustation of 11 stationary points of monitoring on the vertical rock of biogeographical testing ground (island Galindez, Antarctic Region). They are presented by morphologically various forms of bacteria (n x 10(7) cells in 1g of sample), yeast (n x 10(5)) and fungi (n x 10(4)-10(6)). Threshold and lethal UV dozes for isolated monocultures of the Antarctic microorganisms are determined. The threshold doze of UV radiation which is a measure of ability of a cell to reparation of DNA damages for bacteria was 40-70 J/m2. The lethal UV doze (LD99.99) for bacteria varied within the limits of 200-480 J/m2, for yeast of 700-1200 J/m2. Both pigmented and not pigmented bacteria were resistant to UV radiation. As a rule, Gram-positive bacteria were more resistant to UV than Gram-negative ones. It is shown, that resistance of investigated Antarctic rocky microorganisms to UV radiation is their genetically stable characteristic.
Subject(s)
Fungi/radiation effects , Gram-Negative Bacteria/radiation effects , Gram-Positive Bacteria/radiation effects , Adaptation, Physiological , Antarctic Regions , DNA Damage , Fungi/genetics , Gram-Negative Bacteria/genetics , Gram-Positive Bacteria/genetics , Radiation Tolerance , Ultraviolet RaysABSTRACT
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.
Subject(s)
Bacteria, Aerobic/growth & development , Bacteria, Anaerobic/growth & development , Hydrogen/isolation & purification , Bacteria, Aerobic/metabolism , Bacteria, Aerobic/physiology , Bacteria, Anaerobic/metabolism , Bacteria, Anaerobic/physiology , Biofuels , Fermentation , Hydrogen/metabolism , Solanum tuberosum/chemistry , Spores, BacterialABSTRACT
Microbial proteolytic enzymes are able to hydrolyze various protein substrates. Data concerning the ability to degrade proteins amongst various groups of microorganisms, such as bacteria, fungi, actinomycetes and yeasts, are collected in this article. The physical and chemical properties of proteolytic enzyme preparations and methods of their separation and purification have been examined. The possible ways of these enzymes application in industry and medicine have been discussed. The paper is presented in Ukrainian.
Subject(s)
Ascomycota/enzymology , Aspergillus/enzymology , Bacillus/enzymology , Mucor/enzymology , Peptide Hydrolases/isolation & purification , Peptide Hydrolases/chemistry , Substrate SpecificityABSTRACT
The schemes of isolation and purification of proteolytic complex of Bacillus sp. have been developed, which include fractionation by ammonium sulphate and separation on TSK-gels: ion-exchange chromatography on Toyopearl DEAE-650 (M) and gel-filtration on Toyopearl HW-50. It has been established that the proteolytic complex Bacillus sp. is presented by neutral and alkali proteases (pH optimum at 6.0-8.0 and 10.0), which hydrolyse a number of protein substrates: casein, gelatin, hemoglobin, fibrin, and elastin. Two proteolytic complexes with dominating fibrinolytic and elastase activity and molecular weight 28.7 and 22.7 kDd were isolated as a result of purification. It was found out that the obtained enzymatic preparations belong to the group of serine protease which need metal ions for development of their activity.
