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L I Puchkova

Publications and source records attributed to L I Puchkova.

At least 19 recordsLinked to original sources
PubMed1999

[Identification and characterization of strains of Bacillus thuringiensis by genomic fingerprinting using biotinylated phage M13 DNA].

Genomic DNA of the entomopathogenic bacterium Bacillus thuringiensis was analyzed by the genomic fingerprinting technique. The biotin-labeled single-stranded DNA of the phage M13 was used as a marker of hypervariable sequences. A procedure for analyzing the differentiation among various Bacillus thuringiensis strains was developed. Characteristic patterns of fingerprints were obtained for several strains, the main representatives of subspecies that are most frequently used in the manufacture of bacterial insecticides, such as subsp. thuringiensis, subsp. kurstaki, and subsp. galleriae. Because no essential differences were revealed in band patterns upon comparing fingerprints of crystal-producing bacterial strains with those of acrystallic mutants, it was assumed that the loss of crystal-producing ability in the insect pathogen Bacillus thuringiensis is not connected with significant rearrangement of its genome.

Bacillus thuringiensis↗
PubMed1996

[Identification and classification of strains of microorganisms using genomic fingerprinting with biotinylated phage M13 DNA].

To analyze DNA polymorphisms of various bacterial strains, a nonradioactive variant of the genomic fingerprinting method was developed. The method was based on the application of biotin-labeled single-stranded phage M13 DNA as a probe. Characteristic patterns of fingerprints obtained by MvaI, HaeIII, and HinfI restriction enzymes are presented for several species of bacilli and other bacteria. The advantages of this method in microbiology for the identification and characterization of different microbial strains are shown.

Bacillus↗
PubMed1976

[Species specificity of morphogenetic factors of Acetabularia, localized in the cytoplasmic zone adjacent to the cell membrane].

The species specificity of the factors controlling the cap development was established in the experiments with the transplantation of both the intact and centrifuged in the basal direction apical regions of Acetabularia meditteranea on nuclear basal regions of A. crenulata. These factors are found at the stage of 72 hrs of regeneration primarily in the cytoplasmic zone adjacent to the cell membrane which is not displaced during centrifugation. Using direct measurements and radiochemical method, we have shown that the accumulation of proteins proceeded in this zone due, mainly, to their transition from the cytoplasmic zone displaced during centrifugation.

Acetabularia↗
PubMedDate not supplied

[Testing and isolation of high-purity restriction endonucleases].

A new method of testing restriction nucleases is proposed. This method is based on high-temperature treatment of crude cell extracts. Disrupted cells were heated at 50-60 degrees C, centrifuged, and assayed for restrictases. This method provides the opportunity for screening new enzymes in microbial strains enriched with nonspecific restrictases. High-temperature treatment of cell extracts of certain producers reduces the number of steps of the procedure used for isolating high-purity restrictases; the resulting preparations are capable of maintaining high enzymatic activity during long-term storage. It was shown that high-temperature treatment can be applied not only to thermophilic but also to mesophilic strains of microorganisms of different taxa.

Bacteria↗
PubMedDate not supplied

[Restriction endonuclease Sst 12I from a strain of Streptomyces sp. recognizing the nucleotide sequence 5'-CTGCAG-3'].

A new restriction endonuclease Sst12I belonging to the II type and recognizing the sequence 5'-CTGCAG-3' was isolated from the bacterial strain Streptomyces sp. St-12. The enzyme hydrolyzes DNA between adenine and guanine residues; thus, it is a true isoschizomer of restrictase PstI. In contrast to PstI, the restriction endonuclease Sst12I hydrolyses DNA both at 37 degrees and 55 degrees C and remains active after long-term storage.

Bacteriophage lambda↗
PubMedDate not supplied

[Entomopathogenic bacteria Bacillus thuringiensis as producers of restriction endonucleases].

A total of 115 collection strains of Bacillus thuringiensis, belonging to various subspecies, have been studied for the presence of DNA restriction-modification systems. Restriction endonucleases of 13 strains have been isolated and characterized. No considerable correlations between the taxonomic positions of the bacteria and the specificities of the endonucleases isolated have been detected. It is concluded that the enzymes with identical specificities are present in both the crystalliferous and acrystalliferous strains of the same subspecies.

Bacillus thuringiensis↗
PubMedDate not supplied

[Genomic and phenotypic analyses of microorganisms isolated from the sediments of Lake Baikal].

Genetic and biochemical methods and morphological examination were used to study microorganisms isolated from samples of deep drilling of the Lake Baikal bottom sediments. Based on blot hybridization patterns, the strains investigated were divided into several groups according to the degree of homology of their genomic DNA. Morphological, biochemical, and ultrastructural characteristics of bacterial strains are described, and their compliance with the genomic analysis data is demonstrated.

Bacteria↗
PubMedDate not supplied

[Termination of DNA transcription by a poly(dA).poly(dT) fragment inserted into pBR325 plasmid].

A recombinant DNA was constructed by inserting polynucleotide (dA).(dT) of 80-100 base pairs long into EcoRI site of the pBR325 plasmid DNA. Transcription of this DNA was studied in E. coli RNA polymerase system in vitro. Some transcripts obtained with the recombinant plasmid were shown to have poly(U) clusters at the 3'-ends. Obtained data indicate that poly(dA).poly(dT) sequence acts as a terminator of RNA synthesis. Orientation of this sequence in recombinant DNA was also established.

Base Composition↗
PubMedDate not supplied

[Dynamics of accumulation of extracellular proteins of Serratia marcescens and their nuclease activity during cell growth].

Serratia marcescens, strain B-10 M-1, liberates an unspecific endonuclease into the extracellular nutrient solution. Two peaks of the enzyme activity were found in the cultural broth during growth of the cells. The dynamics of accumulation of protein fractions in the cultural broth was studied, and the relative electrophoretic mobility of the enzyme-active part of the proteins was established.

Bacterial Proteins↗