[The effect of different Yersinia pestis antigens on the cellular link in immunity].

Immunization with live plague vaccine has been shown to give no protection to thymectomized mice from subcutaneous challenge with Y. pestis virulent strain. Under the action of the vaccine or individual Y.

[The role of T-suppressors in the formation of plague immunity in mice].

Antiplague immunization of mice causes an increase in the number of T-suppressors in their thymus and spleen; this increase is especially pronounced after injection of a low-immunogenic dose of the vaccine strain. T-suppressors specific to Yersinia pestis antigens were detected in the thymus on day 3 after a single injection and on day 14 after two injections of the vaccine strain.

[Effect of substances altering the DNA molecular conformation on plasmid transformation, plasmid recombination and plasmid transduction in Bacillus subtilis].

The influence of ethidium bromide, actinomycin D and acridine orange treatment of Bacillus subtilis competent cells on plasmid transformation, recombination and transduction was studied. The drugs were administered at different times after DNA uptake. The yield of plasmid recombinants and transformants was inhibited in different ways during the first 30 minutes.

[Plasmid transformation and transduction in different rec-mutants of Bacillus subtilis].

The ability of different Bacillus subtilis rec mutants for transformation and transduction by plasmid DNA and influence of these mutations on plasmid recombination was studied. The efficiency of plasmid transformation was found to be decreased in most cases. Plasmid transduction depended slightly on any rec mutation in recipient cells.

Study of the phenomenon of marker rescue in plasmid transformation and transduction of intact cells, protoplasts and different rec mutants of Bacillus subtilis.

Marker rescue in plasmid transformation of competent cells of different rec mutants of B. subtilis was studied. In most cases the value of marker rescue decreased proportionally to reduction of plasmid transformation efficiency (although there were certain exceptions).