It was shown that immobilization of lactic acid bacteria into organic gels (gelatin and gum) increased the titers of viable cells after 2 months of storage by 2.5–4 times in comparison to the control sample, and immobilization in gels of mixed composition (silanol-humate) led to their increase by 1–2 orders of magnitude. Storage of bacterial preparations in gels is promising for application in food industry and agrobiotechnologies.
Bacteria of the phylum Verrucomicrobiota colonize a wide spectrum of terrestrial and aquatic habitats. One of the ecosystems where verrucomicrobia represent a significant part of the indigenous microbial community are wetlands. All earlier published information regarding phylogenetic diversity of verrucomicrobia in wetlands, however, refers to raised bogs, while verrucomicrobial diversity in fens remains poorly explored. In this study, we performed a comparative diversity analysis of Verrucomicrobiota in six fens of Vologda region. Nucleotide sequences of verrucomicrobia comprised 4 to 7% of all 16S rRNA gene reads retrieved from the examined peat samples. The most abundant groups were represented by members of the families Pedosphaeraceae, Opitutaceae and the order Chtoniobacterales, as well as the as-yet-uncultivated order-candidate S-BQ2-57. Numerical correlation between the relative abundance of well-represented taxa and peat characteristics was determined.
During long-term cultivation in a laboratory sequencing batch reactor in the phosphorus removal mode, granule-like aggregates of two morphotypes, differing in their physical structure and microbial composition, with predominance of different microbial physiological groups, were formed out of the activated sludge floccules. Phosphate-accumulating bacteria Candidatus “Accumulibacter” prevailed in one morphotype, and glycogen-accumulating bacteria Candidatus “Competibacter,” in the other. These are aerobic microorganisms, known to compete for the substrate during the anaerobic period of the anaerobic/aerobic cultivation cycle. Aggregate formation paralleled development of phosphate-accumulating microorganisms, increase in their relative abundance, and higher phosphorus removal efficiency.
For the first time, phytopathogenic fungi of the genus Coleophoma were detected in the lichen genus Stereocaulon paschale (L.) Hoffm. On agarised nutrient medium, strain NM10F28209 formed compact, dense colonies with black ingrowing mycelium and ashy-grey aerial mycelium. Morphological characteristics and analysis of the ITS region of the gene cluster encoding ribosomal RNAs allowed us to assign the new strain to the genus Coleophoma; the closest relative was Coleophoma cylindrospora (Desm.) Höhn. (1919) with 98.28% of similarity. On prolonged incubation for 20 days, the culture formed a brown pigment that diffused into the agar. Extraction using a chloroform:acetone (1 : 1) mixture resulted in a multi-component preparation exhibiting fungicidal activity against yeasts from the Yarrowia and Candida genera. A compound belonging to the group of echinocandins, for which fungicidal activity has previously been demonstrated, was detected in the complex preparation by thin layer chromatography.
The S genotype (first described in Sicily, hence the name) is a part of the Euro-American lineage of Mycobacterium tuberculosis. Here, we report a method for its detection based on PCR-RFLP of the Rv0557 gene. The method was optimized on strains with known whole genome sequences and further applied to screening the DNA collections from Russia, Bulgaria, China, Japan, and Vietnam. PCR-RFLP analysis confirmed the S genotype in strains with the spoligotypes SIT34 (ancestral to S) and SIT1253 (Yakutia strains). Strains from Bulgaria with abridged spoligoprofiles SIT4 and SIT125 were also assigned to the S genotype. The developed method provides for rapid detection of the M. tuberculosis S genotype and reliably resolves phylogenetic ambiguity of the disputed spoligotypes.
The specific enzymatic reaction of sulfur reduction to hydrogen sulfide catalyzed by the HydSL hydrogenase of T. bogorovii BBS has so far been observed only in native cells. In this work, we were able to detect the hydrogen-dependent reaction H2 + S0 → H2S + HS– + H+ in a cell homogenate of these bacteria. This was achieved by destroying the cells in an optimized buffer of high ionic strength. Further purification of the preparation led to a 28-fold increase in its specific activity.
High-performance sequencing of the 16S rRNA gene (V4 region) was used to reveal the most widespread groups of microorganisms in the bottom sediments of the Barents and Kara seas. In the Barents Sea, these were uncultured bacteria of the families Hyphomicrobiaceae, Anaerolineaceae, Desulfobulbaceae, and Desulfosarcinaceae (Sva0081 sediment group), actinobacteria of the genus Rhodococcus, and proteobacteria of the genus Woeseia. In the Kara Sea the most represented groups were uncultured bacteria of the order Sedimentisphaerales (the SG8-4 cluster, class Phycisphaerae, phylum Planсtomycetota), bacteria of the family Anaerolineaceae, the family Desulfosarcinaceae (the SEEP-SRB1 cluster), the deep phylogenetic cluster NB1-j, organotrophic proteobacteria of the genera Woeseia and Pseudomonas, and sulfate reducers of the genus Desulfatiglans. The patterns of microbial distribution were analyzed depending on the depth from the bottom surface and the presence of fluid discharge zones. It was found that according to analysis of the core microbiome, uncultured bacteria of the SG8-4 cluster and uncultured bacteria of the family Anaerolineaceae predominated in the methane discharge zones in the Barents and Kara seas.
The goal of the present work was to determine the effect of different concentrations of an organic carbon source (molasses) on the biooxidation of gold-bearing pyrite−arsenopyrite flotation concentrate, as well as on the composition of microbial populations that formed during the biooxidation process. Biooxidation activity increased with increasing molasses concentration in the medium. Concentration of molasses had a greater effect on the total number of microorganisms, while the relative numbers of microorganisms of different groups did not differ significantly. Thus, it was shown that the use of cheap organic substrates is promising to increase the efficiency of biohydrometallurgical processes.
Investigation of prokaryotic communities from different horizons of the bottom sediments in the Kandalaksha Gulf, White Sea revealed two characteristic groups of sampling points. The first group demonstrated stratification of prokaryotic communities depending on the horizon depth, while the second one, with uniform prokaryotic communities, was typical of the sections with active organic matter decomposition. Microorganisms involved in decomposition of labile organic compounds (Woeseia and Sandaracinaceae), as well as sulfate reducers (SEEP-SRB1 and Sva0081) predominated in the upper horizons of the stratified sediments (the first group of samples). In the lower layers (30 and 50 cm), the share of microorganisms potentially involved in the degradation of complex compounds (e.g., Desulfatiglans, Hyphomicrobiaceae, and Mycobacterium) increased. The share of prokaryotes with unknown metabolism, such as JS1, SG8-4, WCHB1-81, Aerophobales, and S085, increased as well. Thus, the structure of prokaryotic communities was affected by the presence and abundance of organic matter, which decreased with depth.
Herein we present the results of optimization of silver nanoparticles biosynthesis using a nonpathogenic soil bacterium Azospirillum brasilense. The conditions and parameters for synthesis of biogenic nanoparticles using A. brasilense vegetative cells, culture liquid, and homogeneous polyphenol oxidase preparations were analyzed. We have revealed the ranging effect of the incubation time, the concentration of silver ions, pH of the reaction mixture, and the concentration of metabolites, towards the production of colloidal silver nanoparticles with specified geometric parameters, high colloidal stability and relatively good monodispersity. The size, shape, and relative yield of electron-dense nanostructures were determined by transmission electron microscopy and dynamic light scattering; extinction spectra were recorded by UV-vis spectrophotometry.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：