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UV irradiation is known to cause harmful effects on microorganisms. As the result, microorganisms have developed protection against exposure to harmful UV irradiation. We suggested that resistance to UV might be specific characteristic of certain genera of microorganisms. So, the aim of the work is to assess whether there is a correlation between UV resistance and the taxonomic position of microorganisms or is it the adaptation of cells to extreme conditions. There were studied 67 strains from extreme ecosystems (phytocenoses and оrnithogenic soil of the Antarctic, hypersaline ecosystems of the Crimea and the Dead Sea, the lake Baikal). Sequence of 16S rRNA genes, phylogenetic analysis and UV resistance were performed according to standard procedures. Phylogenetic analysis revealed live representatives of the following genera: Pseudomonas, Serratia, Rheinheimera, Aeromonas, Buttiauxella, Brevundimonas, Sphingomonas, Sphingopyxis, Dermacoccus, Frondihabitans, Microbacterium, Rhodococcus, Janthinobacterium, Arthrobacter, Micrococcus, Kocuria, Sphingobacterium, Flavobacterium, Chryseobacterium, Bacillus, Staphylococcus, Paenibacillus, Sporosarcina. Gram-positive bacteria were significantly more resistant to UV irradiation (LD99.99 750–1400 J/m2). Gram-negative had lower resistance (LD99.99 35–150 J/m2). Most pigmented strains were more resistant to UV than non-pigmented ones. According to the values of lethal doses of UV irradiation we suggest that investigated microorganisms have effective mechanisms to repair DNA damages. Resistance of microorganisms to UV, as a rule, was not related to the ecological features of their habitat. Thus, there is a correlation between the resistance of microorganisms to UV irradiation and their taxonomic position, which allows to consider UV resistance as a diagnostic feature at the genus level.

To design an algorithm of decreasing dentin hypersensitivity in children after professional oral hygiene.Intact teeth extracted for orthodontic reasons in children and adults were involved in the pilot study. The enamel surface was cleaned by manual instruments and then polished with polishing pastes containing sodium bicarbonate, fluoride, calcium and phosphates. The results were studied with the help of a scanning electronic microscope. 60 14-15 years schoolchildren, the residents of Krasnogorsk, a town in the Moscow region, took part in the study. All of them were diagnosed dental plaque (K03.6) and underwent professional oral hygiene by manual instruments. Then the teeth were polished with polishing toothpastes. To reduce dentin hypersensitivity after these procedures the SENSODYNE Rapid Relief toothpaste was applied.The pilot study showed a destructive effect of a manual instrument on the tooth enamel especially in children. The data of the scanning electronic microscope demonstrated that the manual method with the use of polishing pastes containing sodium bicarbonate, fluoride, calcium and phosphates led to a significantly lower negative effect of this manual method on the tooth enamel both in children and adults. The application of SENSODYNE Rapid Relief by children at home after professional oral hygiene led to a decrease of dentin hypersensitivity by 65, 37%.The designed algorithm of the children's follow-up procedures after professional oral hygiene includes the application of polishing pastes containing sodium bicarbonate, fluoride, calcium, phosphates and the Sensodyne Rapid Relief toothpaste at home. This helps to minimize negative consequences of manual tooth plaque removal in case of professional oral hygiene.Разработка алгоритма снижения повышенной чувствительности зубов у детей после проведения профессиональной гигиены.Было проведено экспериментальное исследование с использованием сканирующего электронного микроскопа на интактных, удаленных по ортодонтическим показаниям зубах детей (20 зубов) и взрослых (20 зубов), которым проводилась обработка поверхности эмали ручными инструментами, с дальнейшим полированием поверхности эмали зубов полировочной пастой с содержанием бикарбоната натрия, фторида, кальция и фосфатов. Было обследовано 60 школьников Красногорска Московской области в возрасте 14—15 лет с диагнозом зубные отложения (К03.6). Им проводилась профессиональная гигиена с использованием ручных инструментов, с дальнейшим полированием зубов полировочной пастой и использованием зубной пасты SENSODYNE Мгновенный Эффект для снижения повышенной чувствительности зубов.В ходе экспериментального исследования выявлены данные о повреждающем действии ручных инструментов на поверхность эмали зубов, особенно выраженные у детей. Согласно данным сканирующего электронного микроскопа применение полировочной пасты с бикарбонатом натрия, фторида, кальция и фосфатов привело к значительной минимизации негативного воздействия профессиональной гигиены с использованием ручных инструментов на поверхность эмали зубов как у детей, так и у взрослых. Применение зубной пасты SENSODYNE Мгновенный Эффект детьми в домашних условиях привело к снижению повышенной чувствительности зубов после профессиональной гигиены на 65,37%.Разработанный алгоритм тактики ведения детей после профессиональной гигиены, включающий применение полировочной пасты с бикарбонатом натрия, фторида, кальция и фосфатов и использование детьми зубной пасты SENSODYNE Мгновенный Эффект в домашних условиях позволяет минимизировать негативные последствия удаления зубных отложений ручным методом при проведении профессиональной гигиены.

Aim. To determine species composition and taxonomic position of extremotolerant Antarctic yeast. Methods. The objects of research were yeast from Antarctic soils and phytocenosis, which are stored in the Collection of Extremophilic Microorganisms at the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, Kiev. Yeast were grown on malt wort (рН 5.0–5.5, temperature 18–20°С). Isolation of genomic DNA was performed using a commercial kit DNA-sorb; amplification of DNA preparations – use of primers NL1 and NL4; phylogenetic analysis – construction of dendrograms showing the position of the studied strains among closely related and typical species. Results. The analysis have shown a high percentage of similarity (98.4–99.9 %) of 18S rRNA genes sequences of yeast Antarctic strains and yeast sequences from the database GenBank. It was found that yeast strains belonged to phylum Basidiomycota (genera Rhodosporidium, Rhodotorula) and Ascomycota (genus Exophiala). Conclusions. As it was shown by phylogenetic analysis, red yeast S33, S48, S182 clustered with Rhodotorula mucilaginosa; S14 – with Rhodosporidium diobovatum and can be attributed to these species. Extremotolerant black yeast S10, S36 and S237 refer to the species Exophiala nigra. Keywords:Antarctica, extremotolerant yeast, phylogenetic analysis, species composition.

For heterotrophic microorganisms (44 strains) isolated-from the surface film of Lake Baikal, iden- tification was carried out and their. physiological and biochemical characteristics were determined. Com- pared to the water column, diversity of cultured heterotrophs was low, indicating formation of stable micro- bial communities at the air-water interphase interface. Heterotrophic bacteria isolated from the surface mi- crolayer exhibited the enzymatic activity comparable to that for strains form other biofilm associations. Deinococcusfi6us strain NA202 'vas the most active component of the community, capable of utilization of the broadest spectrum of mono- and disaccharides,'sugars, and amino acids. This strain possessed the highest diversity of extracellular enzymes and was the most resistant to UV radiation. The physiological and bio- chemical properties of this strain may-be responsible for its adaptation to survival in extreme conditions of the surface microlayer. Our results improve our understanding of occurrence of UV-resistant strains in freshwater ecosystems.

Purpose To determine resistance to dehydratation of bacteria resistant to UV irradiation. Methods Objects of research - extremophilic bacteria (from Antarctic islands and hypersaline reservoirs of Israel and Crimea). Dehydratation of bacteria was carried out in sealed desiccator; the exposure without access of moisture was 5 weeks, temperature - 22 - 25 °C, humidity - 1 - 4 %. UV irradiation of bacteria was carried out by lamp BUF 15 (A = 254 nm) in the range of 40 - 2400 J/m(2). After cultivation irradiated and not irradiated strains (before and after UV irradiation and before and after drying) we determined the number of cells. Results The extremely resistant to dehydratation (Firmicutes) and extremely sensitive to dehydratation (Proteobacteria, Bacteroidetes) strains was found among the studied bacteria. Most strains of bacteria that were resistant to dehydratation were also resistant to UV irradiation. Survival after dehydratation in these bacteria was 6.32 - 55.26 % and UV LD99.99 240-600 J/m(2). Instead, representatives of Proteobacteria were extremely sensitive to these extreme factors: the cell survival was 0 - 1.6 % after dehydratation and UV LD99.99 80 - 180 J/m(2). Conclusions The results support the hypothesis that between bacteria resistance to electromagnetic radiation (UV) and their resistance to dehydratation there is a correlation.

To determine resistance to dehydratation of bacteria resistant to UV irradiation.Objects of research - extremophilic bacteria (from Antarctic islands and hypersaline reservoirs of Israel and Crimea). Dehydratation of bacteria was carried out in sealed desiccator; the exposure without access of moisture was 5 weeks, temperature - 22 - 25 °C, humidity - 1 - 4 %. UV irradiation of bacteria was carried out by lamp BUF 15 (A = 254 nm) in the range of 40 - 2400 J/m(2). After cultivation irradiated and not irradiated strains (before and after UV irradiation and before and after drying) we determined the number of cells.The extremely resistant to dehydratation (Firmicutes) and extremely sensitive to dehydratation (Proteobacteria, Bacteroidetes) strains was found among the studied bacteria. Most strains of bacteria that were resistant to dehydratation were also resistant to UV irradiation. Survival after dehydratation in these bacteria was 6.32 - 55.26 % and UV LD99.99 240-600 J/m(2). Instead, representatives of Proteobacteria were extremely sensitive to these extreme factors: the cell survival was 0 - 1.6 % after dehydratation and UV LD99.99 80 - 180 J/m(2).The results support the hypothesis that between bacteria resistance to electromagnetic radiation (UV) and their resistance to dehydratation there is a correlation.

Multi-resistant to extreme factors spore-forming bacteria of Bacillus genus are isolated from hypersaline environments of the Crimea (Ukraine) and the Dead Sea (Israel). Phylogenetic analysis showed distinction of dominating extremophilic culturable species in studied regions. In Crimean environments they are B. mojavensis and B. simplex, in the Dead Sea ecosystem--B. subtilis subsp. spizizenii, B. subtilis subsp. subtilis, B. licheniformis and B. simplex. Isolates are simultaneously halotolerant and resistant to UV radiation. Strains isolated from the Dead Sea and the Crimea environments were resistant to UV: LD90 and LD99.99 made 100-170 J/m2 and 750-1500 J/m2 respectively. Spores showed higher UV-resistance (LD99.99-2500 J/m2) than the vegetative cells. However the number of spores made 0.02-0.007% of the whole cell population, and should not significantly affect the UV LD99.99 value. Isolates of both environments were halotolerant in the range of 0.1-10% NaCl and thermotolerant in the range of 20-50 °C, and didn't grow at 15 °C. Survival strategy of spore-forming bacteria from hypersaline environments under high UV radiation level can be performed by spore formation which minimize cell damage as well as efficient DNA-repair systems that remove damages.

For heterotrophic microorganisms (44 strains) isolated-from the surface film of Lake Baikal, iden- tification was carried out and their. physiological and biochemical characteristics were determined. Com- pared to the water column, diversity of cultured heterotrophs was low, indicating formation of stable micro- bial communities at the air-water interphase interface. Heterotrophic bacteria isolated from the surface mi- crolayer exhibited the enzymatic activity comparable to that for strains form other biofilm associations. Deinococcusfi6us strain NA202 'vas the most active component of the community, capable of utilization of the broadest spectrum of mono- and disaccharides,'sugars, and amino acids. This strain possessed the highest diversity of extracellular enzymes and was the most resistant to UV radiation. The physiological and bio- chemical properties of this strain may-be responsible for its adaptation to survival in extreme conditions of the surface microlayer. Our results improve our understanding of occurrence of UV-resistant strains in freshwater ecosystems.

Antarctic plants are stable specific microenvironments for microbial colonization that are still less explored. In this study, we investigated cultivable heterotrophic bacteria and yeasts dominating in plant samples collected from different terrestrial biotopes near Ukrainian Antarctic Base on Galindez Island, maritime Antarctica. Phylogenetic analysis revealed affiliation of the bacterial isolates to genera Pseudomonas, Stenotrophomonas, Brevundimonas, Sporosarcina, Dermacoccus, Microbacterium, Rothia and Frondihabitans, and the yeast isolates to genera Rhodosporidium, Cryptococcus, Leucosporidiella, Candida and Exophiala. Some ecophysiological properties of isolated strains were determined that are important in response to different stresses such as psychro- and halotolerance, UV-resistance and production of hydrolytic enzymes. The majority of isolates (88 %) was found to be psychrotolerant; all are halotolerant. Significant differences in survival subsequent to UV-C radiation were observed among the isolates, as measured by culturable counts. For the bacterial isolates, lethal doses in the range 80-600 J m⁻² were determined, and for the yeast isolates--in the range 300-1,000 J m⁻². Dermacoccus profundi U9 and Candida davisiana U6 were found as most UV resistant among the bacterial and yeast isolates, respectively. Producers of caseinase, gelatinase, β-glucosidase, and cellulase were detected. To the best of our knowledge, this is the first report on isolation of UV resistant strain D. profundi, and Frondihabitans strain from Antarctica, and on detection of cellulase activity in Antarctic yeast strain C. davisiana. The results obtained contribute to clarifying adaptation strategies of Antarctic microbiota and its possible role in functional stability of Antarctic biocenoses. Stress tolerant strains were detected that are valuable for ecological and applied studies.

Microorganisms, superresistant to toxic metals, have been revealed in a geographical zone of internal island shelf of Antarctic peninsula (30x60 km) on islands Darboux, Lippmann, Berthelot, Cruls, Barchans, Jalour, Uruguay, Scua, Three pigs, Winter, Grotto, Galindez, Pitermann, Booth, capes Perez, Rasmussen, Tuxen (coast of Antarctic peninsula), and also on distant from them island King-George. The highest number of metalresistant microorganisms is revealed on the medium containing 1000 ppm of Cr(VI) - up to 5,0х10⁵ cells/g of soil and on the medium containing 250 ppm of Ni²⁺ – 3,0-5,0x10⁵ cells/g of soil.

It is established, that the total number of chemoorganotrophic aerobic microorganisms in a soil, sludge of reservoirs, on a grass, mosses and lichens on islands Galindez, Skua, Corner, Barchans, Irizar, Uruguay, Jalour, Petermann, Berthelot, Cruls, Three little pigs, King-George made 10⁵–10⁸ cells/g of a sample that is less on 2-3 order, than in regions with a temperate climate. From samples of moss, lichen, grass, soil are isolated methylotrophic bacteria (10²–10⁴ cells/g of a sample). It is shown, that in the Antarctic lichens frequency of an occurence of coal-black yeast and also their total number is significantly higher (10²–10⁴ cells/g of sample), than in other Antarctic biotopes. Coal-black pigments are extracted from Antarctic yeast Exophiala nigra. These pigments are identical to melanin according to results of studying of specific chemical tests, UV spectra and other properties. For the first time presence on vertical rocks in Antarctic Region of bacteria and yeast, resistant to high dozes UV radiations is shown. The lethal doze of UV radiation for Antarctic pink pigmented strains Methylobacterium exceeded 200–250 J/m², for coal-black yeast – 500–800 J/m², for red-pigmented yeast – 1200–1500 J/m². In whole, in the Antarctic Region representatives of several phylogenetic lines are found out: Proteobacteria, Firmicutes, Actinobacteria, and also yeast. Obtained results indicate to a taxonomic diversity of microorganisms in terrestrial biotopes of Antarctic Region.

Multi-resistant to extreme factors spore-forming bacteria of Bacillus genus are isolated from hypersaline environments of the Crimea (Ukraine) and the Dead Sea (Israel). Phylogenetic analysis showed distinction of dominating extremophilic culturable species in studied regions. In Crimean environments they are B. mojavensis and B. simplex, in the Dead Sea ecosystem--B. subtilis subsp. spizizenii, B. subtilis subsp. subtilis, B. licheniformis and B. simplex. Isolates are simultaneously halotolerant and resistant to UV radiation. Strains isolated from the Dead Sea and the Crimea environments were resistant to UV: LD90 and LD99.99 made 100-170 J/m2 and 750-1500 J/m2 respectively. Spores showed higher UV-resistance (LD99.99-2500 J/m2) than the vegetative cells. However the number of spores made 0.02-0.007% of the whole cell population, and should not significantly affect the UV LD99.99 value. Isolates of both environments were halotolerant in the range of 0.1-10% NaCl and thermotolerant in the range of 20-50 °C, and didn't grow at 15 °C. Survival strategy of spore-forming bacteria from hypersaline environments under high UV radiation level can be performed by spore formation which minimize cell damage as well as efficient DNA-repair systems that remove damages.

Strain Methylomonas rubra 15shT, deposited in several collections of microorganisms (NCIMB 11913T, = UCM B-3075T = ACM 3303T), is the subject of numerous studies. However, the name of this strain is not valid, primarily due to the phenotypic similarity of t-species M. rubra to the species M. methanica. The results of the present study and data available in the literature indicate that M. rubra deserves the status of a separate species. Strains of M. rubra differ from strains of M. methanica in a number of properties, such as the ability to reduce nitrates to nitrites, the structure of intracytoplasmic membranes, and the presence of a new coenzyme Q. The distinctions between the species M. rubra and M. methanica were confirmed by comparison of electrophoretic patterns of their cellular proteins, by results of DNA-DNA hybridization, and by the data from 16S rRNA gene sequencing (the level of phylogenetic homology between these two species was below 95%). Phylogenetic and phenotypic analyses showed that strains of M. rubra cannot be assigned to any species of the genus Methylomonas. Results of polyphasic analysis suggest an independent taxonomic status of strain Methylomonas rubra 15shT. This paper contains description of Methylomonas rubra sp. nov. with the type strain 15shT = NCIMB 11913T = UCM B-3075T = ACM 3303T. The nucleotide sequence of the 16S rRNA gene of strain 15shT has been deposited in the GenBank database under the accession number AY995198.

Search of methylotrophic bacteria has been carried out during time VIIth Ukranian Antarctic expedition (2003) at station «Academic Vernadsky». The psychrotolerant bacteria obligately using a methane have been found out in samples of mosses in an island part of Antarctic Region and in soil-plant samples. The quantity of methane oxidizing bacteria in samples from Antarctica (101–103 /g of the sample) was lower, than in samples from regions with a temperate climate (102–106 /g of the sample). The psychrotolerant bacteria of genus Methylobacterium facultatively using a methanol have been revealed in the silt of fresh and «Red» lakes, and also in soil-plant samples. Single psychrophilic strain which, probably is a new species of genus Methylobacterium was isolated at 10oС from soil-plant sample of Antarctic Region. The majority of the collection mesophilic strains Methylobacterium isolated earlier from soils and plant phyllosphere from various regions of Ukraine is shown, that, also were capable to grow at 10oС. It was shown, that strains Methylobacterium are not catalysts of process of formation of ice. Moreover, some from them are capable to reduce temperature of freezing of water (process of crystallization of ice at their presence began at temperature lower-13°С), that is, naturally they have «antifreezing»effect on process of crystallization of ice. These properties of strains Methylobacterium may be very important in conditions of Antarctica for a survival both microbic, and plant forms. As a whole, psychrotolerant facultative methylotrophs and the obligate methane oxidizing bacteria revealed by us in various ecosystems of Antarctic Region, expand representation about a physiological diversity of these groups of bacteria, about their distribution to biosphere and the contribution to a global cycle of carbon.

The drying of soil samples reduced the abundance (especially of predominant species) and the diversity of bacteria isolated from these samples, making easier the isolation of rare bacterial species. Some bacterial species that were minor before soil drying became dominant in dried soil samples. In general, soil drying allowed the diversity of soil bacteria to be determined more adequately. The bacteria that were isolated from dried soil samples turned out to be resistant to gamma radiation (with LD90 = 2.8–4.6 kGy) and desiccation. It is concluded that soil drying may serve as a model for the action of stress factors on natural bacterial populations. The hypothesis that periodic desiccation was the primary cause of formation of bacterial radioresistance in nature is discussed.

34 strains of aerobic chemoorganotrophic microorganisms were isolated from 23 soil and plant samples selected from highland biotopes of Ecuador-Andes massif (Papallacta, 4020 m), ash at the foot of the volcano Tungurahua, mountainous jungle (La Favorita, 1600 m), as well as in humid tropic botanical garden (state Puyo, 950 m). In mountain jungle samples the high number of bacteria--10(5)-10(7) CFU/g of sample were represented by 2-5 morphotypes. In highland (4020 m) samples the bacterial counts made from 10(2) to 10(7) CFU/g of sample. The current study describes resistance of isolated strains to high salinity, UV radiation and toxic metal ions. The majority of isolated strains were halotolerant. Isolates from volcanic ash showed high resistance level to UV radiation--LD99,99 made 1000-1440 J/m2; resistance level for isolates from the soil of Puyo Botanical Garden and isolates from rock lichen (Papallacta) LD99,99 made 1160 and 800 J/m2 respectively. Strains isolated from mountain jungle (La Favorita) showed lower UV-resistance. In highland biotopes of Ecuador occurred bacteria resistant to toxic metal ions. The highest resistance to Hg2+ was shown by isolate of lichen from mountain jungle, the maximal growth concentration was 0.025 g/L; to Cr(VI)--by isolate from lichen rock massif--3,0 g/L. Correlation between metal-resistance, halotolerace and UV resistance for studied strains was not detected, probably because of different microbial cell damage/repair mechanisms under the action of these factors.

The pink-pigmented facultative methylotrophic bacteria (PPFMB) of the genus Methylobacteriumare indispensible inhabitants of the plant phyllosphere. Using maize Zea maysas a model, the ways of plant colonization by PPFMB and some properties of the latter that might be beneficial to plants were studied. A marked strain, Methylobacterium mesophilicumAPR-8 (pULB113), was generated to facilitate the detection of the methylotrophic bacteria inoculated into the soil or applied to the maize leaves. Colonization of maize leaves by M. mesophilicumAPR-8 (pULB113) occurred only after the bacteria were applied onto the leaf surface. In this case, the number of PPFMB cells on inoculated leaves increased with plant growth. During seed germination, no colonization of maize leaves with M. mesophilicumcells occurred immediately from the soil inoculated with the marked strain. Thus, under natural conditions, colonization of plant leaves with PPFMB seems to occur via soil particle transfer to the leaves by air. PPFMB monocultures were not antagonistic to phytopathogenic bacteria. However, mixed cultures of epiphytic bacteria containing Methylobacterium mesophilicumor M. extorquensdid exhibit an antagonistic effect against the phytopathogenic bacteria studied (Xanthomonas campestris, Pseudomonas syringae, Erwinia carotovora, Clavibacter michiganense,andAgrobacterium tumifaciens). Neither epiphytic nor soil strains of Methylobacterium extorquens, M. organophillum, M. mesophilicum, andM. fujisawaensecatalyzed ice nucleation. Hence, they cause no frost injury to plants. Thus, the results indicate that the strains of the genus Methylobacteriumcan protect plants against adverse environmental factors.

Bacteria that produce exopolysaccharides (EPS) and use methane as the only source of carbon were selected by studying a collection of methanotroph strains: Methylococcus capsulatusE 494, 874, and 3009; M. thermophilus111p, 112p, and 119p; Methylobacter ucrainicus159 and 161; M. luteus57v and 12b; Methylobactersp. 100; Methylomonas rubra15 sh and SK-32; Methylosinus trichosporiumOV3b, OV5b, and 4e; M. sporium5,12, A20d, and 90v; and Methylocystis parvusOVVP. Mesophilic methanotroph strains with the ribulose monophosphate way of C1-compound assimilation synthesized EPS more actively than bacteria operating the serine cycle. The dynamics of EPS synthesis by methanotrophs during chemostat cultivation was studied.

Methanotrophic bacteria utilize only methane (some species methanol) as a source of carbon and energy. They can co-metabolize a number of non-growth substrates due to the low specificity of methane monooxygenase (MMO). The reducer for monooxygenation is obtained during dehydrogenation of intermediates of methane oxidation. During growth on methane, co-metabolism of non-growth substrates leads to exhaustion of the methanotroph energy sources, accumulation of toxic products and growth cessation. To evaluate a role of the monooxygenation process in the metabolism of methanotrophs, co-metabolism of methanol and a substrate of MMO (ethane or carbon monoxide) was studied during the growth of Methylomonas rubra 15sh and Methylococcus thermophilus 111p. These organisms, being grown at low copper content, did not oxidize naphthalene. Thus, they possess particulate MMO, which can use reducing equivalents at the level of methanol dehydrogenase. Methanol did not support growth of Mc. thermophilus 111p. Growth of Mm. rubra 15sh on methanol was inefficient and was accompanied by accumulation of formaldehyde. When a second substrate (ethane or carbon monoxide) was added into the gas phase (5–20 vol.%), the growth of Mc. thermophilus 111p occurred, and the yield from methanol of Mm. rubra 15sh was enhanced. At low methanol concentration (to 12.5 mM), the yield of the Mm. rubra 15sh biomass from methanol was proportional to the amount of the second substrate co-oxidized, and the whole methanol utilized was converted into biomass. Theoretical calculations showed that such high efficiency of growth could be achieved when MMO received reducing equivalents from methanol dehydrogenase and, moreover, electron transport chain from NADH to MMO contained a proton translocating segment. Thus, monooxygenation of the MMO substrate was profitable for the methanotroph metabolism. During the growth of methanotrophs studied on methanol plus ethane or carbon monoxide, the major part of electrons of methanol utilized was used for the monooxygenation of the MMO substrate. For methanotrophs, this allows to consider the monooxygenation process as the energy yielding mechanism of the electron transport to oxygen.

The properties of In2O3-based ceramic sensors, doped with Pt4+ and Au3+ ions, at detection of NH3 and other reducing gases have been compared. It was stated that Pt increases while Au decreases In2O3 sensitivity to NH3. The ceramics resistance decreases, when In2O3 is doped with Pt. Au addition to In2O3 leads to the opposite effect. The high sensitivity of In2O3–Pt sensors to NH3 and decrease of In2O3–Pt ceramics resistance, when compared with undoped In2O3, may be caused by the formation of InxPty in In2O3–Pt systems. In2O3–Pt sensors allow analysing the content of NH3 in air in the concentration range of 15–2000 ppm.

We studied parameters of hemostatic homeostasis in isolated and combined exposure to low-intensity γ-irradiation in a low dose, hyperbaric oxygenation, and antiorthostatic hypokinesia. Complex effects of the above stress factors are accompanied by a pronounced hypercoagulable shift with signs of thrombinemia against the background of depressed fibrinolysis, which indicates the risk of intravascular blood coagulation.

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.

The interaction and the electronic state of the components in the RuO2–TiO2 film system, obtained by the sol–gel method from poly(butyl titanate) and ruthenium chloride, are considered. After the films had been heat-treated in air at 770 K a composite oxide film was formed, which is mostly a phase of solid solution of TiO2 in RuO2. Further annealing of the film in H2 led to deterioration of the solid solution and partial reduction of both components, Ti4+ and Ru4+ions. Within the reduced system ruthenium in oxidation states 0–VIII was identified by XPS. Titanium appeared in the form of non-stoichiometric TinO2n– 1, oxides, mostly Ti4O7, but TiO and Ti2O are also possible.

Transparent fine-granular SnO2 and SnO2-Pd films (SnO2 verage particle size 25–30 nm) have been obtained by annealing of tin hydroxide sols, stabilised with oleic acid. The structure of the films was investigated by TEM, ED and Mossbauer spectroscopy. In SnO2-Pd films, annealed at 800 °C, palladium is present as homogeneously distributed thermally stable particles (d = 5–8 nm). Observed isomeric shifts of 119Sn Mossbauer spectra suggests the presence of partially reduced tin ions, Sn2+ and Sn3+, in the films. Deeper reduction of SnO2 and formation of SnO are observed in SnO2-Pd films, annealed at 500 °C. Thin-film sensors based on sol-gel obtained SnO2 and SnO2-Pd are high-sensitive to different gases (H2, CH4, NO, CO). They enable detection of CO and CH4, CO and NO selectively in mixtures by controlling of sensor's operating temperature.

Complex treatment with acetylsalicylic acid, heparin, and dexamethasone improves the efficiency of photodynamic therapy in rats with myosarcoma-I.

Natural latent human antibodies cross-reacting with DNA and cardiolipin, interact with human endothelial cells, decrease antiaggregation activity of rat aortic wall, and increase fibrinolytic activity of the wall of the inferior vena cava. It is assumed that natural antiphospholipid antibodies present in immunoglobulin preparations in a latent state modify antithrombogenic activity of the vascular wall and are a potential cause of antiphospholipid syndrome.

Complex treatment with acetylsalicylic acid, heparin, and dexamethasone improves the efficiency of photodynamic therapy in rats with myosarcoma-I.

51 methane-oxidizing bacteria strains such as Methylomonas methanica, M. rubra, Methylococcus capsulatus, M. thermophilus, M. luteus, M. ucrainicus, M. whittenburyi, Methylosinus trichosporium, M. sporium, Methylocystis parvus isolated from various ecological niches and geographical regions of the Ukraine and also the strains received from R. Whittenbury and Y. Heyer were screened for restriction endonucleases. Type II restriction endonucleases were detected in IMV B-3112 (= 12 b), IMV B-3027 (= 26), IMV B-3019 (= 9 c), IMV B-3017 (= 17 c), IMV B-3226 (= 26 v), IMV B-3033 (= Y), IMV B-3100 (= 100) and IMV B-3494 (= 1E494). The results obtained were indicative of relatively high frequency of restriction enzymes occurrence in methane-oxidizing bacteria. There were Kpn I (Asp 7181) restriction endonuclease isoschizomers in crude extracts of IMV B-3112, B-3017, B-3019, B-3027 isolated from fresh-water silt as well as in IMV B-3226 strain isolated from waste-water silt. Although these isolates had bee previously considered as untypical strains of M. ucrainicus, more detailed study of their properties allowed placing them with Methylovarius luteus (= Methylococcus luteus). IMV B-3494 strain was identified as Methylococcus capsulatus. Strain IMV B-3033 had earlier been allocated to Methylovarius whittenburyi (= Methylococcus whittenburyi). Specificity of restriction endonucleases of this strain was not tested. Therefore, for the first time restriction endonucleases were detected in methane-oxidizing bacteria. 8 strains (3 species) among 51 strains (13 species) were found to produce restriction endonucleases displaying three different types of specificity in the least. Producers of restriction endonucleases having Kpn I (Asp 7181) specificity were isolated from different water and silt samples of the Dnieper flood-land more than 20 years ago.

The interaction and the electronic state of the components in the RuO2–TiO2 film system, obtained by the sol–gel method from poly(butyl titanate) and ruthenium chloride, are considered. After the films had been heat-treated in air at 770 K a composite oxide film was formed, which is mostly a phase of solid solution of TiO2 in RuO2. Further annealing of the film in H2 led to deterioration of the solid solution and partial reduction of both components, Ti4+ and Ru4+ions. Within the reduced system ruthenium in oxidation states 0–VIII was identified by XPS. Titanium appeared in the form of non-stoichiometric TinO2n– 1, oxides, mostly Ti4O7, but TiO and Ti2O are also possible.

High molecular weight compounds find wide application at the present time in modern medicine as raw materials for the preparation of instruments, sanitation articles, materials for stomatology, medicaments, blood substitutes, and for producing artificial organs [4, 9]. Prostheses of the latter present the science with several problems, the most important being the investigation of the reaction of polymers with tissues and blood of the organism. One of the principal requirements of polymers for medical purposes is their antithrombogenic character, and therefore production of polymers, which do not cause the production of thrombi is a current problem. We studied the influence of a "Diflon" polycarbonate, poly(butylene terephthalate), poly(4-methylpentene), polyfluoroethylene resin, a TPU-3BT polyurethane, and polyethylene on the hemocoagulation process, the electrophoretic mobility of erythrocytes and thromboeytes and the resistance of erythrocytes in hydrochloric acid. The results of biochemical investigations are given for connective tissue capsules developing around polymeric materials made of a PPE-201 polyurethane and polyethylene, in order to study the biocompatibility of tissues and blood of animals with the above polymers.

This paper concerns prospects in the use of immobilized cells of methane-oxidizing bacteria as bioorganic catalysts. Test unit for studies of catalytic properties of immobilized cells of bacteria utilizing gases as source of nutrition has been designed. Cometabolism of nongrowth substrates by immobilized cells of methane-oxidizers has been investigated. The catalytic properties of immobilized cells have been established to be markedly influenced by both the chemical composition of a carrier and type of binding of cells to the surface of a carrier. Silochromes modified by the toluylenediisocyanate and carboxyl groups as well as agar gel appear to hold much promise for immobilization of methane-oxidizing cells, and nonmodified silochrome and asbestos have considerable promise for immobilization of methane-producing cells. Results obtained indicate that the immobilized cells of methane-oxidizing and methanogenic bacteria can be used as a convenient model in studying processes of methane synthesis and conversion. KEYWORDS Immobilization; cometabolism; methane oxidation; methane production; carbon cycle.