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卷 92, 编号 5 (2023)
ОБЗОРЫ
Collections of Microalgae and Cyanobacteria in Russia: Present State, Problems, and Prospects
摘要
Abstract—
Biological collections are systematic repositories of living cultures or fixed preparations and provide researchers with the material required both for basic and applied studies and for educational activities. A collection sample is the only reliable evidence of the existence of a living organism in time and space, whose multifunctionality allows it to be studied as a part of biodiversity and as a bioresource for the development of biotechnologies. Microalgae are an ancient ecological group of taxonomically diverse organisms (cyanobacteria, diatoms, charophytes, green and yellow-green algae, etc.), possessing unique physiology, broad ecological valency and plasticity, which results in their predominance in various habitats. This evolutionarily successful group is also in high demand for commercial applications in environmental monitoring, agriculture, bioenergetics, pharmacy, and the food industry. The analysis of data from an independent survey of 21 Russian collections of microalgae and cyanobacteria is provided. The survey included information on the main characteristics of the collections (funds, profile, methods, document management, etc.), emerging problems, and approaches to their solution.
429-440
ЭКСПЕРИМЕНТАЛЬНЫЕ СТАТЬИ
Ancylobacter crimeensis sp. nov., a New Species of Aerobic Methylotrophic Bacteria Isolated from Oak Phyllosphere
摘要
Abstract—
A new facultative methylotroph, strain 6x-1T, was isolated from the phyllosphere of oak (Quercus pubescens Willd.) on the medium with methanol. Cells were aerobic, gram-negative, not-spore-forming, non-motile short ovoids rods reproducing by binary fission. Growth optimum was at 25‒29°C and pH 7.0‒7.5; growth was inhibited by 1.5% NaCl. Predominant fatty acids were C18:1ω7c and C19:0cyclo. Predominant phospholipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, and diphosphatidylglycerol. Tha major ubiquinone was Q10. The 16S rRNA gene sequence of strain 6x-1T exhibited the highest similarity to those of members of the genus Ancylobacter (97.0‒97.4%). Genome analysis of strain 6x-1T and most closely related Ancylobacter strains revealed that the values of ANI (80.7‒83.5%), dDDH (22.4‒23.3%), AAI (72.0‒78.0%), and POCP (62.0‒69.0%) were below the recommended threshold values for prokaryotic species. Genome size of strain 6x-1T was 4.29 × 106 Mb, and G + C content was 67.3%. According to the results of phylogenetic, phylogenomic, phenotypic, and chemotaxonomic analysis, strain 6x-1T (=VKM В-3256T = ССUG 72401T) represents a new species of genus Ancylobacter, for which the name Ancylobacter crimeensis sp. nov. is proposed.
441-452
Seven New Actinobacterial Species of the Genus Kribbella with Unique Cell Wall Glycopolymers, and Emended Description of the Genus Kribbella
摘要
Abstract—
Seven actinomycete strains assigned to seven new species of the genus Kribbella were isolated from soils of different regions in Russia. The strains exhibited 98.2–99.3% similarity of the 16S rRNA gene sequences to each other and 96.2–99.7% similarity to the type strains of the known Kribbella species. The evolutionary distances calculated on the basis of concatenated gene sequences (gyrB–rpoB–recA–relA–atpD, 4108 nt) for the studied organisms and type strains of the known species were within the range reported for Kribbella species (0.014–0.101). The dDDH and ANIb values for the strains studied and the type strains of validly described species with available genomes were below the threshold (49.8 and 92.6%, respectively) for prokaryote specie delineation. Members of the putative new species possessed individual phenotypic profiles; some species were found (for the first time in Kribbella) to produce sporangium-like structures, up to 4 μm in diameter. The cell walls of the studied strains contained the teichuronic and/or teichulosonic acids specific for the species or species groups and not described previously for other prokaryotes. The unique branched α-mannan occurred in all studied strains of the genus. Based on the data obtained and the previously published data, the following new species are proposed: Kribbella orskensis sp. nov. (type strain ВКМ Ас-2538T), Kribbella rubisoli sp. nov. (type strain VKM Aс-2540T), Kribbella antiqua sp. nov. (type strain VKM Ас-2541T), Kribbella kalugense sp. nov. (type strain VKM Ас-2570T), Kribbella steрpae sp. nov. (type strain ВКМ Ас-2572T), Kribbella pratae sp. nov. (type strain ВКМ Ас-2574T), and Kribbella voronezhensis sp. nov. (type strain VKM Ас-2575T) with emended description of the genus Kribbella.
453-466
Molecular Genetic and Functional Analysis of the Rap-Phr Signal System of the Plasmid pBS72 of Bacillus subtilis Isolates
摘要
Abstract—
The functional characteristics of the Rap-Phr quorum sensing signal system of the plasmid pBS72 were investigated. Phylogenetic relationship was revealed between Rap phosphatase coded by the plasmid pBS72 and the homologous polypeptides RapP and RapI determined by the plasmid pBS32 (68.4% identity) and the ICEBs1 conjugative transposon (36.9% identity). Similar to the phylogenetically related phosphatases, the studied Rap protein had a negative effect on sporulation. Unlike the known signal systems, Rap-Phr proteins were found to affect the viability of plasmid-bearing donor bacteria in the course of conjugative transfer of the plasmid pBS72 in the isogenic system. Impaired rap-phr genes resulted in a 10-fold decrease in the number of viable donor cells with the mutant plasmid after 3 and 4 h, and in a 100-fold decrease after 24 h. The number of formed transconjugants remained almost the same. Our results provide the basis for investigation of the mechanisms responsible for the effect of extrachromosomal genetic elements on the donor bacteria, providing for the propagation of the pBS72-like plasmids in natural environments.
467-476
Methane Production in a Temperate Freshwater Lake during an Intense Cyanobacterial Bloom
摘要
Abstract—
Seasonal cyanobacterial blooms have a negative impact on freshwater ecosystems. The role of cyanobacteria in methane production and their relationship with methanogenic archaea are not yet well understood. The goal of the present work was to identify the features of methanogenesis in the water column and sediments of a profoundal part of the freshwater Lake Senezh (Moscow oblast) during a period of cyanobacteria over-bloom. Analytical, radiotracer, microscopic, molecular biological, and incubation techniques were used. Alkalization and oxygen oversaturation of the 0–2-m water layer were caused by intensive photosynthesis. The near-bottom water (4 m) was pH-neutral and hypoxic; the sediments were reduced. Methane was detected throughout the water column; its concentration in the surface water was an order of magnitude lower than in the near-bottom water and 4 orders of magnitude lower than in the sediments. Cyanobacteria of the species Microcystis aeruginosa predominated in the photic zone (up to 30% of the total number of the 16S rRNA gene fragments). The sequences of cyanobacteria and freshwater members of the SAR11 clade, which can potentially be involved in aerobic methanogenesis via decomposition of methylphosphonates (MPn), were also detected. The sequences of hydrogenotrophic methanogens of the genus Methanoregula, which are potentially capable of methanogenesis in cooperation with cyanobacteria, were revealed in oxygen-supersaturated water. Hydrogenotrophic and aceticlastic pathways of methanogenesis predominated in reduced sediments. Sequences of methanogens of to the orders Methanomicrobiales, Methanobacteriales, Methanosarciniales, and Methanomassiliicoccales were detected there. Cyanobacterial bloom promoted methanogenesis both in the photic zone of Lake Senezh (due to MPn decomposition and anaerobic methanogenesis in association with cyanobacterial aggregates) and in the near-bottom water and sediments (due to oxygen depletion and excessive release of substrates caused by sedimentation and degradation of cyanobacterial mortmass).
477-489
Compatible Solutes Accumulated by Glutamicibacter sp. Strain SMB32 in Response to Abiotic Environmental Factors
摘要
Abstract—
Proton magnetic resonance spectroscopy was used for investigation of the pool of compatible solutes accumulated in the cells of Glutamicibacter sp. strain SMB32 in response to abiotic environmental factors. The original habitat of the strain was anthropogenically salinated soil at the Verkhnekamsk deposit of potassium and magnesium salts (Perm krai, Russia). The strain grew within the temperature range from 5 to 35°C. At 5 and 32°C, the intracellular content of trehalose in the cells of Glutamicibacter sp. SMB32 was significantly higher than at 25°C. Glutamicibacter sp. SMB32 was able to grow both in the absence of NaCl and at its concentrations up to 11%. Glutamate predominated in the cells growth without NaCl. At high salinity (8% NaCl), predominant compounds in the studied strain cells were trehalose, proline, glutamine, and glutamate. Increasing salinity of the growth medium resulted in higher levels of intracellular proline. This is the first report of ability of a Glutamicibacter strain to synthesize mannitol; its accumulation was found to depend on the aeration mode. Thus, Glutamicibacter sp. strain SMB32 possesses high metabolic plasticity and is able to adapt to the action of unfavorable physicochemical factors.
490-499
Adaptive Properties of Arthrobacter agilis Strain wb28 Isolated from Wheat Bran
摘要
Abstract
—The article presents the results of a study of some adaptive properties of a bacterial isolate from wheat bran, identified by the 16S rRNA gene as an Arthrobacter agilis strain. According to the literature data, A. agilis does not belong to the dominant bacterial species of wheat microbial associations and activates growth at low ambient temperatures. The studied A. agilis strain showed poor growth in a microbial consortium when an aqueous suspension of wheat bran, partially fermented at 28 ± 1°C by the native microbiota, was plated on a dense MPA medium and produced the pigment after three weeks of storage at 4 ± 1°C. Moderate growth of bacteria without increased pigmentation was observed during its subsequent transfer after low-temperature storage on agar media containing carbohydrates and nitrogen compounds, mineral salts, and vitamins that were more easily utilized than native bran. The growth of colonies upon plating on such media increased in the series: thermally fermented wheat bran → HMF agar → LB (without salt). It was revealed that the A. agilis strain, which was not typical of the wheat bran microflora, under the influence of osmotic and/or temperature shock (in response to a sharp change in the NaCl concentration and/or a difference in ambient temperatures) produced pigments both in agar and liquid cultures. According to the results of spectral analysis, the pigment was assigned to carotenoids and tentatively identified as bacterioruberin. Quantitative evaluation showed that, under stress conditions during submerged cultivation, the studied strain A. agilis wb28 was able to synthesize the pigment at the level of 52.8 mg/L (17.2 mg/g biomass).
500-509
Biodegradation Patterns of Composite Materials Based on High-Density Polyethylene and Starch
摘要
Abstract
—The degradation properties of high-density polyethylene composites filled with amylose and amylopectin polysaccharides were studied. At low dosages of the polysaccharides (0.5% wt/wt), no change in viscosity, molecular weight and physical and mechanical characteristics of HDPE samples were observed, while an increase in the proportion of the natural filler (starch) to 1 and 5% resulted in a decrease in mechanical properties, although the values of deformation and strength parameters satisfied the minimum necessary requirements for film packaging. After incubation in soil for one year, the sample of HDPE film with a corn starch content of 5% (wt/wt) was found to undergo the greatest changes in its properties. The study of ability of aerobic microorganisms to carry out the surface transformation of the studied film composites revealed that bacteria of the genus Bacillus efficiently colonized the polyethylene-starch composites. Among the identified microorganisms, micromycetes of the genus Penicillium and Trichoderma caused the most pronounced changes in the structure of the studied polymer composites, and the greatest effect was achieved in the case of synergistic action of different micromycetes genera.
510-520
КРАТКИЕ СООБЩЕНИЯ
High Efficiency of Removal of Pathogenic Microorganisms at Wastewater Treatment Plants in the City of Moscow
摘要
Abstract—
While most pathogenic bacteria are efficiently removed from wastewater during biological treatment, some pathogens, notably Arcobacter, may be abundant in the purified water. Using 16S rRNA gene profiling, the composition of microbial communities of municipal wastewater in the city of Moscow was studied before and after biological purification at the Lyubertsy wastewater treatment plant. Fecal contaminants of the genera Acinetobacter, Aeromonas, Arcobacter, Bacteroides, Streptococcus, and Veillonella, which include human pathogens, predominated in the influent wastewater. After treatment, the relative abundance of these bacteria decreased by 50‒100 times. Predominant organisms in the microbiome of the effluent water were bacteria characteristic of activated sludge, including the nitrifiers of the genera Nitrospira and Nitrosomonas, as well as phosphate- and glycogen-accumulating microorganisms. Thus, pathogenic bacteria, including Arcobacter, are effectively removed at the Moscow wastewater treatment plant.
521-526
Polylactide Degradation in the Presence of Members of the Genus Bacillus
摘要
Abstract—
Microorganisms of the genus Bacillus were shown to have different effects on the degradation of polylactide packaging material. The degradation experiment was carried out on an agar medium at a temperature of 55°C and pH 5.9 for 14 days. This is the first report on the abiotic hydrolysis significantly slowing down during incubation with B. licheniformis S8 and occurring in parallel with the main process, enzymatic hydrolysis. The latter involved sequential cleavage of monomer units from the end of the macromolecule and the formation of low molecular weight products used by microorganisms as a substrate; it contributed to a decrease in the mass of polylactide by 5.1%, while maintaining its molecular weight and decreasing the dispersion of molecular weights. In the presence of bacteria B. amyloliquefaciens, B. subtilis subsp. spizizenii, and B. subtilis subsp. inaquosorum, the polymer weight did not decrease, but the molecular weight decreased significantly, similar to abiotic hydrolysis.
527-532