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A M Lysenko

Publications and source records attributed to A M Lysenko.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Study of intraspecific variations of the bacterium Lactococcus lactis in adaptation to high acidity of the medium].

This paper reports on the study of acid tolerance of lactic acid bacteria as a property of cells, determining their ability to divide efficiently and retain viability under conditions of increased nutrient medium acidity during bacterial growth. The bacteria of the strain TV2, isolated from a self-soured curd, similar to the bacteria of the strain STE05 (Russian National Collection of Industrial Microorganisms), were assigned to the species Lactococcus lactis according to their G+C composition (36.7-36.5 mol %) and the high level of DNA-DNA hybridization (93%). However, these strains were essentially different in the number and size of the plasmids and the chromosomal DNA restriction fragments, as well as in the sensitivity to phages of lactic acid bacteria. It was found that bacteria of the strain TV2 were stable (i.e., they divided efficiently at a pH as low as 5.3) and tolerant to the lactic acid that they produced while growing (i.e., they retained viability at pH 4.4). Bacteria of the strain STE05 lacked acid tolerance (at pH below 6.5, growth was retarded, and pH 5.0 was the lowest value at which the cells remained viable). The acid tolerance and phage resistance of TV2 bacteria are likely to characterize their higher adaptive capacity in comparison with STE05 bacteria. Acid tolerance is inherited in a stable manner and retained by the segregants of TV2 strain obtained in the course of long-term storage of the bacteria. Specifically, the strains TV29, TV13, and TV 229, which displayed this property, had altered physiological and biochemical characteristics (accumulation of biomass and fermentation of lactose) in spite of their genetic identity to the original strain (pulsed-field gel electrophoresis of chromosomal DNA restriction fragments).

Adaptation, Physiological↗
PubMedDate not supplied

[The new facultatively chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium Desulfovermiculus halophilus gen. nov., sp. nov., isolated from an oil field].

The new mesophilic, chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium strain 11-6 could grow at a NaCl concentration in the medium of 30-230 g/l, with an optimum at 80-100 g/l. Cells were vibrios motile at the early stages of growth. Lactate, pyruvate, malate, fumarate, succinate, propionate, butyrate, crotonate, ethanol, alanine, formate, and H2 + CO2 were used in sulfate reduction. Butyrate was degraded completely, without acetate accumulation. In butyrate-grown cells, a high activity of CO dehydrogenase was detected. Additional growth factors were not required. Autotrophic growth occurred, in the presence of sulfate, on H2 + CO2 or formate without other electron donors. Fermentation of pyruvate and fumarate was possible in the absence of sulfate. Apart from sulfate, sulfite, thiosulfate, and elemental sulfur were able to serve as electron acceptors. The optimal growth temperature was 37 degrees C; the optimum pH was 7.2. Desulfoviridin was not detected. Menaquinone MK-7 was present. The DNA G+C content was 55.2 mol %. Phylogenetically, the bacterium represented a separate branch within the cluster formed by representatives of the family Desulfohalobiaceae in the subclass Deltaproteobacteria. The bacterium was assigned to a new genus and species, Desulfovermiculus halophilus gen. nov., sp. nov. The type strain is 11-6T (= VKM B-2364), isolated from the highly mineralized formation water of an oil field.

Carboxylic Acids↗
PubMedDate not supplied

[Two new species of microaerophilic sulfur spirilla, Spirillum winogradskii sp. nov. and Spirillum kriegii sp. nov].

New microaerophilic sulfur-oxidizing spirilla were isolated from hydrogen sulfide sludge of wastewater treatment plants. Strains D-427 and D-430 have spiral cells that are highly motile due to bipolar flagellum bundles covered with mucous sheaths. Under a phase-contrast microscope, these bundles are visible as single polar flagella. Spheroplasts are formed in the stationary growth phase. Both strains are obligate organotrophs able to oxidize a number of reduced sulfur compounds. The oxidation of sulfide and polysulfide leads to the formation of intracellular globules of elemental sulfur; thiosulfate oxidation results in tetrathionate accumulation in the medium. The cells are unable to utilize reduced sulfur compounds in the energy metabolism; their oxidation is caused by a chemical interaction with H2O2 and O2, synthesized in the electron transport chain. Both strains are obligate microaerophiles with an optimal oxygen concentration in the gas phase of 2 and 0.8% for strains D-427 and D-430, respectively. The strains utilize a limited number of organic acids as growth substrates, mainly tricarboxylic-acid-cycle intermediates. The DNA G+C content is 38.0 mol % (T(m)) for strain D-427 and 38.9 mol % for strain D-430. Phylogenetic analysis, based on the comparison of 16S rRNA gene sequences, revealed that the new isolates of sulfur spirilla are the most closely related to Spirillum volutans, the type species of the genus (97.4% similarity). They were assigned to the genus Spirillum within the class Beta-proteobacteria as two new species, S. winogradskii sp. nov. (D-427T = DSM 12756T) and S. kriegii sp. nov. (B-430T = BKM B-2372T). The emended description of the genus Spirillum is provided.

Genotype↗
PubMedDate not supplied

[A psychrotolerant Caulobacter sp. from Russian polar tundra soil].

Strain Z-0024, a psychrotolerant aerobic heterotrophic representative of the prosthecate bacteria of the genus Caulobacter, was isolated from a methanotrophic enrichment obtained from Russian polar tundra soil. The cells of the new isolate are vibrios (0.5-0.6 x 1.3-1.8 microm) with a polar stalk. The organism grows in a temperature range from 5 to 36 degrees C, with an optimum at 20 degrees C. The pH range for growth is from 4.5 to 7.0 with an optimum at pH 6.0. Strain Z-0024 utilizes a wide range of organic compounds: sugars, amino acids, volatile fatty acids, and primary alcohols. It tolerates a NaCl concentration in the medium of up to 15 g/l. The G + C content of DNA is 66.6 mol %. The 16S rRNA gene sequence analysis revealed that strain Z-0024 belongs to the cluster of Caulobacter species, showing a 98.8-99.2% sequence similarity to them. DNA-DNA hybridization revealed a low level of homology (24%) between strain Z-0024 and C. vibrioides ATCC 15252. The new isolate is described as Caulobacter sp. Z-0024.

Base Composition↗
PubMedDate not supplied

Characterization of unusual alkaliphilic gram-positive bacteria isolated from degraded brown alga thalluses.

Two orange-pigmented Gram-positive, aerobic bacteria were isolated from enrichment culture during degradation of brown alga Fucus evanescens thalluses. In this work, atomic force microscopy (AFM) has been used to study the cell morphology. The non-contact mode imaging revealed unusual irregular coccoid shape of cells, possessing a single flagellum. Bacteria produced carotenoid pigments, were chemo-organotrophic, alkaliphilic and halo-tolerant growing well on nutrient media containing up to 15% NaCl. Growth temperature ranged from 5 to 45 degrees C. The DNA base compositions were 48 mol% G + C and the level of DNA similarity of two strains was conspecific (98%). A comparative phylogenetic analysis of 16S rRNA gene sequences revealed that the strain KMM 3738 tightly clustered with recently described Planococcus maritimus (99.9% 16S rRNA gene sequence similarity). DNA-DNA hybridisation experiments revealed that DNA from the KMM 3738 showed 12-15% and 16-35% of genetic relatedness with the DNA of type strains of the genera Planomicrobium and Planococcus, respectively, and 87% with DNA from Planococcus maritimus, indicating that new isolates belong to the later species.

Bacterial Typing Techniques↗
PubMedDate not supplied

[Analysis of DNA-DNA homologies in obligate methylotrophic bacteria].

The genotypic affinity of 19 bacterial strains obligately dependent on methanol or methylamine as carbon and energy sources was studied by techniques of molecular DNA hybridization. The high homology level (35-88%) between motile strain Methylophilus methanolovorus V-1447D and nonmotile strain Methylobacillus sp. VSB-792 as well as other motile strains (Pseudomonas methanolica ATCC 21704, Methylomonas methanolica NRRL 5458, Pseudomonas sp. W6, strain A3) indicates that all of them belong to one genus. Rather high level of homology (62-63%) was found between Methylobacillus glycogenes ATCC 29475 and Pseudomonas insueta ATCC 21276 and strain G-10. The motile strain Methylophilus methylotrophus NCIB 10515 has a low homology (below 20%) to other of the studied obligate methylobacteria. Therefore, at least two genetically different genera of obligate methylobacteria can be distinguished, namely Methylophilus and Methylobacillus, the latter being represented by both motile and nonmotile forms.

Bacteria↗
PubMedDate not supplied

[Nucleotide composition and homologies in the DNA of new extreme halophilic soil archaebacteria].

DNA nucleotide composition was studied in extreme halophilic bacteria belonging to the genera Halobacterium, Halococcus, Natronobacterium and Natronococcus. The cultures were shown to be a monolithic group of microorganisms with the content of GC pairs typical of extreme halophilic archebacteria. The difference between the content of DNA major and minor components was twice as high in Halobacterium distributus strains isolated from sulfate saline soils as compared to cultures of this species isolated from natural waters with a high salinity. DNA minor components were not found in haloalkalophilic microorganisms from soda saline soils in contrast to those from soda lakes. The results of DNA-DNA hybridization indicate that the Halobacterium genus is highly heterogeneous. The newly isolated strains of extremely halophilic H. distributus are characterized by the low homology of their DNAs both among themselves and with other species of the genus. However, the hybridization data for the collection strains H. vallismortis 1398 and H. halobium 996 from the National Collection of Microorganisms are indicative of a high homology (80-100%) which is not characteristic of cultures belonging to different species. These results as well as some phenotypical properties of H. vallismortis 1398 different from those of this species type strain support the data reported in the literature about the genetic instability of extreme halophilic archebacteria. The analysis of homologies in DNA nucleotide sequences may be used to study the taxonomy of extreme halophilic archebacteria.

Base Sequence↗
PubMedDate not supplied

[Purification, heterogeneity and some properties of T2 bacteriophage lysozyme].

Free T2 bacteriophage lysozyme is isolated and purified from 80 l portion of phagolysate by means of ballast protein and bacterial debris precipitation with rivanol, two-stage fractionation on amberlit IRC-50 and chromatography on CM-Sephadex C-50. Purified enzyme is homogenous under polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate, it has a molecular weight value similar to that in the literature. A presence of two active enzyme forms (I and II) is demonstrated. They can be separated by means of analytical electrophoresis in polyacrylamide gel at pH 4,5 and of ion-exchange chromatography on Amberlite IRC-50. T2 lysozymes I and II do not differ in their amino acid composition, ORD parameters, and they are not interconversible. Heterogeneity of phage lysozyme is shown not to be an artefact and to be due neither to heterogeneity of the initial phage poluation, nor to aggregation and to oxidation of enzyme SH-groups. The content of alpha-helix regions, as estimated by ORD is higher in phage lysozyme than in hen egg-white lysozyme, which evidences that these proteins are non-homologous.

Amino Acids↗
PubMedDate not supplied

[The level of DNA homology in species of the genus Cytophaga].

Nucleotide composition, genome size and DNA homologies were studied for strains Cytophaga johnsonae DSM 425, C. pectinovora DSM 6368, C. saccharophyla DSM 1811, C. aquatilis DSM 2063, C. flevensis DSM 1076, C. lytica ATCC 23 178, C. arvensicola DSM 3695, C. heparina DSM 2356. A considerable difference in GS-bases level between species of genus Cytophaga (33.3-34.9 mol %) and incertae sedis species (C. heparina and C. arvensicola) (45.0-46.7 mol. %) was shown. The differentiation between freshwater and soil, on the one hand, and seawater species, on the other hand, was determined. The degree of DNA-resemblance between them was 2-13%. The existence of relationship between freshwater and soil species was demonstrated. The homology in DNA of freshwater and soil species (C. johnsonae, C. pectinovora and C. saccharophyla) was 22-37%. The heterogeneity of genus Cytophaga and the necessity of its revision are supported.

Base Composition↗