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O A Didyk

Publications and source records attributed to O A Didyk.

5 recordsLinked to original sources
PubMed1990

[Mapping of the c-region of the temperate phage 59 of Erwinia carotovora 268].

The present communication deals with the genetic mapping of the temperate bacteriophage 59 immunity region. Morphological mutants of the c-type of the temperate bacteriophage 59 were isolated after UV-treatment of the phage. Complementation analysis of 36 c-mutants has shown that the bacteriophage 59 c-region consists of at least four genes responsible for the establishment of lysogenization. The two-factor crosses were used to determine the mutual positions (order and distances) of the c-mutations. The order of the c-genes is C1--C3--C2--C4. The three c-genes are localized in a short region of the phage 59 chromosome, but the fourth gene is located in the separate locus.

Bacteriophages↗
PubMedDate not supplied

[Factors that affect transduction in microorganisms].

Data from literature concerning general and specialized transduction in microorganisms are given in the paper. The process of exogenic DNA penetration to the cells of bacteria and participation of protein products of separate phage genes in this process are described. The so-called E-proteins in a set with DNA penetrate through a cell membrane. In phage P22 they are protein products of phage genes 7, 16, 20. In P22 mutants with an altered transducing frequencies (HFT and LFT) the due functions are also coded by the phage genes. It is shown that the process of DNA packing in phages P22, phi 80, lambda and others is genetically determined. The gene transfer frequency depends on UV radiation and the very nature of transducing phages itself. In virulent phages the UV radiation up to inactivation level 95-99% evokes a decrease of their "killer" ability, which is accompanied by an increase of survivability of the formed transductants and, as a result, by enhancement of the transduction transfer frequency. An important role of the transduction analysis for fine mapping of a genome of microorganisms and its significance for practice are shown. A mathematical analysis of the data on cotransduction of linkage markers is presented as such that may be used when determining the value of transduced fragment of a chromosome.

Bacteria↗
PubMedDate not supplied

[Phage-plasmid interactions in bacteria].

A review is devoted to consideration of the basic types of interaction of moderate and virulent bacteriophages and extrachromosomal elements in bacterial cells. Various experimental data confirm diversity of such interactions as well as resistance of bacteria to productive phage infection. Role of plasmids in such processes as abortion infection, lysogenic state, reparation of phage DNA as well as the effect of plasmids on the basic stages of phage development in the cells are analyzed. Possible mechanisms for limiting development of phages as a result of plasmids' presence in bacterial cells are considered.

Bacteria↗
PubMedDate not supplied

[Influence of glutaraldehyde on Na+, K+-ATPase activity of brain tissue and enzymic preparations under conditions of electron cytochemical analysis].

The glutaraldehyde inhibitory influence on Mg2+, Na+, K+-ATPase activity of the brain tissue is shown to increase with a rise in the glutaraldehyde concentration; a direct dependence is established between the degree of inhibition and the treatment time and temperature. The glutaraldehyde inhibitory effect on the activity of the brain microsomal fraction Na+, K+-ATPase preparations under the same treatment conditions is considerably higher. A histochemical detection of the cerebral cortex Mg2+, Na+, K+-ATPase was carried out under optimal conditions of fixation, and a conclusion is made on possibility of using glutaraldehyde as a fixator in histochemical investigations.

Aldehydes↗