Publications by authors named "Esikova T"

In this work, a new Ch2 strain was isolated from soils polluted by agrochemical production wastes. This strain has a unique ability to utilize toxic synthetic compounds such as -caprolactam (CAP) as a sole carbon and energy source and the herbicide glyphosate (GP) as a sole source of phosphorus. Analysis of the nucleotide sequence of the 16S rRNA gene of Ch2 revealed that the strain belongs to the species .

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-Caprolactam (Caprolactam, CAP), a monomer of the synthetic non-degradable polymer nylon-6, is the major wastewater component in the production of caprolactam and nylon-6. Biological treatment of CAP, using microbes could be a potent alternative to the current waste utilization techniques. This work focuses on the characterization and potential use of caprolactam-degrading bacterial strain BS3 isolated from soils polluted by CAP production wastes.

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Microbial interactions play an important role in natural habitat. The long-term coevolution of various species leads to the adaptation of certain types of microorganisms as well as to the formation of a wide variety of interactions such as competitive, antagonistic, pathogenic and parasitic relationships. The aim of this work is a comprehensive study of a new ultramicrobacterium str.

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The intensive development of agriculture leads to the depletion of land and a decrease in crop yields and in plant resistances to diseases. A large number of fertilizers and pesticides are currently used to solve these problems. Chemicals can enter the soil and penetrate into the groundwater and agricultural plants.

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Naphthalene, as a component of crude oil, is a common environmental pollutant. Biochemical and genetic aspects of naphthalene catabolism have been examined in most detail in the bacteria of Pseudomonas genus. In pseudomonads, the key intermediate in naphthalene degradation is salicylate.

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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 ATCC 6633 was studied. The investigated strains of ultramicrobacteria (UMB) were found to inhibit the sporulation process of B. subtilis ATCC 6633 in binary mixed cultures, exhibiting a 3-day delay of the onset of sporulation compared to the control one, an extended period of the prospore maturation, formation of the fraction of immature spores, and development of ultrastructural defects in many endospores.

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We isolated 50 strains of free-living ultrasmall bacteria with a cell volume that varies from 0.02 to 1.3 microm3 from a range of extremal natural biotopes, namely permafrost soils, oil slime, soils, lake silt, thermal swamp moss, and the skin integuments of the clawed frog, Xenopus laevis.

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Five bacterial strains with the unique ability to utilize low-molecular linear caprolactam olygomers (nylon olygomers) were isolated from soil samples contaminated with industrial wastes of epsilon-caprolactam. Based on the properties studied and also on the analysis of 16S rRNA gene nucleotide sequences, the strains BS2,BS3, BS9, BS38, and BS57 were classified to the general Arthrobacter, Brevibacterium, Microbacteriun, Gulosibacter, and Achromobacter, respectively. All of the strains also utilized 6-aminohexanoic and adipic acids, which are intermidiates of the epsilon-caprolactam catabolism.

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The mini-replicon of pseudomonads' caprolactam/salicylate degradation plasmid pBS270 (105 kb, contains incompatibility determinants of P-7 group) has been obtained and its nucleotide sequence has been determined. The new gene encoding TrfA-like replication initiator has been found on this replicon. Poor homology of this replication initiator with known proteins of TrfA-family allows us to classify obtained replicon as IncP-1-like.

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Both caprolactam and salicylate biodegradation by Pseudomonas salicylate/caprolactam degraders is controlled by large conjugative plasmids (SAL/CAP). Some of these plasmids determined to be the members of IncP-7 group. The new salicylate 1-hydroxylase gene (scpA) on SAL/CAP-plasmids has been detected and partially sequenced.

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Two strains (NF1 and NF3) of free-living chemoorganotrophic bacteria have been isolated from multiyear oil slime and Pedilanthus tithymaloides rhizosphere and ascribed to the genus Kaistia of the class Alphaproteobacteria on the basis of the nucleotide sequences of 16S rRNA gene and phenotypic characteristics. These strains can be assigned to ultramicrobacteria as their populations are represented by two subpopulations: (1) ultrasmall cells, on average 200-300 nm in diameter and <0.1 microm(3) in volume, of up to 60% of the total number of cells in a population, and (2) cells 400-800 nm in diameter and 0.

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Cladribine (2-chloro-2'-deoxyadenosine) was synthesized using intact cells of the recombinant Escherichia coli strain producing Geobacillus stearothermophilus B-2194 thermostable purine-nucleoside phosphorylase II (EC 2.4.2.

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Transmission electron and fluorescence microscopy was used to study the character of the interaction of free-living ultramicrobacterial (UMB) strains NF1 and NF3, affiliated with the genus Kaistia, and seven species of gram-positive and gram-negative heterotrophic bacteria. Strains NF1 and NF3 were found to exhibit parasitic activity against gram-positive Bacillus subtilis and gram-negative Acidovorax delafildii. UMB cells are tightly attached to the envelopes of the victim cells and induce their lysis, thus demonstrating the features of typical ectoparasitism.

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The morphology, ultrastructure, and quantity of bacterial nanoforms were studied in extreme biotopes: East Siberia permafrost soil (1-3 Ma old), petroleum-containing slimes (35 years old), and biofilms from subsurface oil pipelines. The morphology and ultrastructure of microbial cells in natural biotopes in situ were investigated by high-resolution transmission electron microscopy and various methods of sample preparation: ultrathin sectioning, cell replicas, and cryofractography. It was shown that the biotopes under study contained high numbers of bacterial nanoforms (29-43% of the total number of microorganisms) that could be assigned to ultramicrobacteria due to their size (diameter of < or =0.

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Gram-negative chemoorganotrophic soil ultramicrobacteria (UMB), strains NF1 and NF3, have been isolated. In their development cycle, the strains formed small coccoid cells of 400-800 nm and ultrasmall cells of 200-300 nm. Phylogenetically, the strains NF1 and NF3 belong to Alphaproteobacteria and are close to the type strain of the recently described species Kaistia adipata.

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The kinetics of conversion of sulfur compounds by Halothiobacillus neapolitanus DSM 15147 bacteria was studied in the presence of steel samples. It was shown that the presence of steel altered the known pathway of sulfur compound oxidation by thiobacteria. Production of atomic hydrogen via the interaction between biogenic sulfuric acid and steel enhanced secondary production of intermediates and decreased the content of sulfate produced previously.

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A genetically marked, plasmid-containing, naphthalene-degrading strain, Pseudomonas putida KT2442(pNF142::TnMod-OTc), has been constructed. The presence of the gfp gene (which codes for green fluorescent protein) and the kanamycin and rifampicin resistance genes in the chromosome of this strain allows the strain's fate in model soil systems to be monitored, whereas a minitransposon, built in naphthalene biodegradation plasmid pNF142, contains the tetracycline resistance gene and makes it possible to follow the horizontal transfer of this plasmid between various bacteria. Plasmid pNF142::TnMod-OTc is stable in strain P.

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Thermophilic and thermoresistant strains of bacilli were screened on a medium containing Chrome Azurol S for producers of siderophores. It was found that the Bacillus licheniformis VK21 strain dramatically increases secretion of the metabolite, a chelator of Fe3+, in response to addition of manganese(II) salts. The growth of the producer on a minimum medium containing MnSO4 under the conditions of iron deficiency is accompanied by the accumulation of a catechol product, the content of which reaches a maximum at the beginning of the stationary growth phase of culture.

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Fourteen thermophilic and thermostable strains of the genus Bacillus were studied. Total DNA was isolated from these strains and used as a template to identify and clone peptide synthetase genes by means of polymerase chain reaction. Amplified DNA fragments were cloned into a phasmid vector, and nucleotide sequences of cloned fragments were determined.

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Three 18-membered analogues of the N-terminal fragment of the sarcotoxin IA cationic antimicrobial peptide were synthesized by the solid phase method of peptide synthesis with the use of swellographic monitoring. The ability of these peptides to inhibit the growth of various bacteria in culture medium and their hemolytic activity in experiments on human erythrocytes were studied. The analogue completely corresponding to the N-terminal amino acid sequence of the natural sarcotoxin IA with the amide group on its C-terminus exhibited higher antibacterial activity.

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A collection of thermophilic strains of the genus Bacillus was made. The strains were screened for antimicrobial activity. Strains VK2 and VK21 isolated from thermal springs of the Kamchatka Peninsula, and antagonistic to several gram-positive bacterial species were chosen for further investigation of antibiotics produced by them.

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