Mikrobiologiia最新文献

Results of genome analysis of a member of the family Ferroplasmaceae, Acidiplasma sp. strain MBA-1, an extremely acidophilic, moderately thermophilic archaeon oxidizing ferrous iron under oxic conditions and utilizing organic compounds. This strain was previously shown to predominate in the community carrying out biooxidation of pyrite-arsenopyrite gold-bearing concentrate. The genome was sequenced using the Illumina HiSeq 2000 platform. A total of 2306800 pairwise reads were obtained, corresponding to 300-fold coverage. Assembly was carried out by three programs in parallel. The optimal assembly contained nine contigs, the genome size was 1747364 bp, and N50 was 446845 bp. Annotation of the genome revealed 1749 protein-encoding sequences, as well as 46 tRNA genes and one rRNA gene copy. The results of genome analysis confirmed the previous data on the physiology of this organism. The gene of sulfocyanin (TZ01_06185), a blue copper-containing protein playing the key role in the iron-oxidizing electron transport chain, was identified in the genome. The genes encoding sulfur oxidoreductase (TZ01_04750) and sulfateadenilyl transferase (TZ01_04545), the enzymes of sulfur oxidation, were also identified. The genes involved in the transport and catabolism of organic compounds and the genes of the 3-hydroxypropionate/4-hydroxybutyrate cycle were revealed. The genome of Acidiplasma sp. MBA-1 is the first genome of this genus deposited to a public database DDBJ/EMBL/GenBank (accession no. JYHS00000000) and is of interest for further investigation of Acidiplasma archaea.

The effect of ultramicrobacterial epibionts of the genera Kaistia (strain NF1), Chryseobacterium(strain NF4), and Stenotrophomonas (strain FM3) on the process of sporulation of Bacillus subtilis ATCC6633 was studied. The investigated strains of ultramicrobacteria (UMB) were found to inhibit the sporulationprocess of B. subtilis ATCC 6633 in binary mixed cultures, exhibiting a 3-day delay of the onset of sporulationcompared to the control one, an extended period of the prospore maturation, formation of the fraction ofimmature spores, and development of ultrastructural defects in many endospores. Thus, investigation ofbinary mixed cultures of B. subtilis and UMB revealed that, apart from suppression of reproduction and lysisof host vegetative cells, inhibition of spore formation and destruction of endospores was yet another featureof intermicrobial parasitism. The UMB parasites of the studied genera are assumed to participate in the regulationof development and reproduction of B. subtilis in natural habitats of this spore-forming bacterium.

Yeast abundance and species diversity on the surface and in inner tissues of Malus domestica andPyrus communis fruits under high anthropogenic impact in the city of Moscow (Russia) were studied. Resultsdemonstrated that abundance of epiphytic yeasts on the fruits increased gradually, reaching the maximum of3.2 × 10⁴ CFU/g on mature fruits. During summer, abundance of endophytes did not change significantly(variation near 2.5 × 10³ CFU/g) until complete maturation, while in September their numbers increased to104 CFU/g. Basidiomycetous yeasts (Filobasidium wieringae, F. magnum, Rhodotorula glutinis, and Rhodosporidioboluscolostri) predominated on the fruit surface. Ascomycetous species were the most diverse groupinside the fruits, which quantitatively increased through maturation. It was found that the share of opportunisticspecies Candida parapsilosis in internal tissues was significant during the entire period of fruit formationand development under anthropogenic impact in the city. Specific properties of epiphytic and endophyticyeast communities developing in natural ecological niches under synanthropic conditions and anthropogenicimpact are discussed.

Recent results related to investigation of the role of intestinal microbiota (IM) in development andfunctioning of the human nervous system are discussed. The role of the microbiota in bidirectional communicationbetween the gastrointestinal tract and the central nervous system is considered. Special attention ispaid to the primary IM of infants, which is actively involved in formation of immune and other physiologicalmechanisms, including the nervous system, and is responsible for the subsequent general and psychicalhealth of a human. The results of research on ability of the commensal intestinal microflora to produce neuroactivecompounds, including neurotransmitters, short- and long-chain fatty acids, γ-aminobutyric acid,etc., are summarized. These compounds may have a considerable effect on development and functioning ofthe central nervous system, including the brain. Research on various animal models is discussed, includinginvestigation of IM effect on behavior, learning abilities and memory, anxiety and depression levels, reactionto emotional stimuli, and stress resistance. A special section deals with probiotic bacteria, which are presentlyconsidered as psychobiotics with preventive and therapeutic potential for treatment of neurological and neurophysiologicaldisorders. Development of new paradigms and concepts, rejection of some classical conceptsof neurobiology is presently the key condition for the future breakthrough in investigation of human nervousactivity.

From the leaves of three urban trees (Tilia sp., Acer sp., and Fraxinus sp.), 180 strains degrading phenanthrene, naphthalene, and salicylate were isolated by direct plating and enrichment cultures. The leaves of each tree species were characterized by a specific profile of aromatic hydrocarbon-degrading microflora. Members of the type Actinobacteria were predominant in the case of direct plating on media with phenanthrene and naphthalene. Enrichment cultures with phenanthrene and salicylate were shown to yield microbial consortia, the composition of which changed with time. Members of the type Proteobacteria were predominant in these consortia. No plasmids of polycyclic aromatic hydrocarbon degradation of the P-7 and P-9 incompatibility groups were revealed in the studied strains.

The lipopolysaccharide (LPS) of Escherichia coli 126 was isolated and studied. The lipid A fatty acid composition of the investigated LPS was similar to that of other members of the family Enterobacteriaceae. The E. coli 126 LPS was more toxic than the LPSs of previously studied E. coli strains and of other members of the Enterobacteriaceae (Budvicia aquatica and Pragia fontium), and was less pyrogenic than pyrogenal. SDS-PAG electrophoresis showed a bimodal distribution typical of S-form LPSs. The LPS of E. coli 126 decreased the adhesive index indicating a possible competition between LPS molecules of E. coli 126 and adhesins of E. coli F-50 on rabbit erythrocytes. The LPS of E. coli 126 in a homologous system showed antigenic activity in the reactions of double immunodiffusion in agar by Ouchterlony. No serological cross-reaction of the LPS of other E. coli strains, as well as of that of the B. aquatica type strain, with the antiserum to E. coli 126 was observed. The structural components of the lipopolysaccharide obtained by mild acid hydrolysis were lipid A, the core oligosaccharide, and the O-specific polysaccharide. Based on the data of monosaccharide analysis and 1H and 13C NMR spectroscopy it was found that the O-specific polysaccharide had the structure characteristic of the representatives of E. coli serogroup O15.

A facultative methylotrophic bacterium, strain Lp-1, which was isolated from root nodules of lupine (Lupinus polyphyllus L.) on the medium with methanol as a carbon and energy source, exhibited high similarity of the 16S rRNA gene sequences to Delftia strains (94‒99.9%). The cells of Delftia sp. Lp-1 were motile gram-negative rods dividing by binary fission. Predominant fatty acids were C16:0 (34.2%), C16:1ω9 (14.5%), and C18:1ω7c (17.3%). Phosphatidylethanolamine, phosphatidylcholine, and phosphatidylglycerol were the dominant phospholipids. Q8 was the major ubiquinone. Optimal growth occurred at 24‒26°C and pH 7.1‒7.3; growth was inhibited by 1% NaCl. The organism oxidized methanol with the classical methanol dehydrogenase and used the ribulose bisphosphate pathway of C1 metabolism. Analysis of translated amino acid sequence of the large subunit of the MxaF methanol dehydrogenase revealed 85.5‒94% similarity to the sequences of such autotrophic methylotrophs of the class Alphaproteobacteria as Angulomicrobium, Starkeya, and Ancylobacter, indicating the possible acquisition of the mxaF gene via horizontal gene transfer. Delftia sp. Lp-1 (VKM B-3039, DSM 24446), the first methylotrophic member of the genus Delftia, was shown to be a plant symbiont, stimulating plant growth and morphogenesis, increasing the level of photosynthetic pigments and specific leaf weight. It possesses the nifH gene of nitrogen fixation, is capable of phosphate solubilization, synthesis of auxins and siderophores, and is antagonistic to plant pathogenic fungi and bacilli.

Abundance and seasonal trophodynamics. (specific growth rate, daily production, and grazing mortality) of the major picophytoplankton components, Synechococcus cyanobacteria (Syn) and picoeukary- otes (Pico-E), were studied at three stations in Sevastopol Bay and adjacent coastal waters (the Black Sea) in 2014 by flow cytometry and the dilution method. Pico- E abundance was shown to increase along the nutrient and pollution gradient from the coastal waters outside the bay (annual average of 7.3 ± 5.4 x 103 cells mL⁻¹) to the eastern corner of the bay (28.7 ± 11.4 x 103 cells mL⁻¹), while no relation was found between the water pollution status.and Syn abundance (9.9 ± 8.7 x 10³ cells mL⁻¹, at all the stations, n=27). Matter flows through the communities (daily production for Syn and Pico-E 0-16.6 and 0-19.3 μg C L- day⁻¹, respec- tively; grazing mortality for Syn and PicoE 0-3.6 and 0-21.2 μg C L⁻¹ day⁻¹, respectively) were comparable to or even exceeded their biomass stocks (<0.05-6.8 and 0.9-26.5 μg C L- for Syn and PicoE, respectively), indicating high biomass turnover rates. The highest flow-to-stock ratio (up to 6 for Syn) and,a significant imbalance between daily production (P) and grazing mortality (G) were observed in the most polluted and eu- trophicated waters of the bay in spring (Pico-E: P/G <.1) and late summer (Syn: P/G > 1). Black River inflow to the bay was hypothesized to be among the mechanisms maintaining.this pronounced and long-term im- balance in the open system without any negative consequences for the picophytoplankton assemlages.

The resi Its of investigation of speleothem (moonmilk) from the Snezhnaya cave (West Caucasus, Abkhazia) are-reported. The structure of microbial complexes from moonmilk was investigated by quantita- tive PCR; strains of culturable microorganisms were isolated and their preferred temperature and carbon sources were determined. Among eubacteria, -34% belonged to the iron bacteria (Rhodoferax). Most bacte- rial strains were shown to be facultative psychrophiles with the maximum growth rate at 4C. The microstruc- ture and elemental composition of mionmilk were investigated using a scanning electron microscope (EVO- 40HV, Carl Zeiss) and silicon drifi X-ay detector X-MAX 80 ffM2' The visually plastic and homogeneous mass of moonmilk was shown to be highly heterogeneous, containing various microstructures. The elemental composition of some nanostructures depended on the structure of bacterial biofilms. Some loci of the biofilm were found to contain up to 46% (wt/wt) of iron oxides. Calcium content was high, up to 61.5% (wt/wt) only in cubic crystalline structures which were not involved in microbiological processes.