[Transposon mutagenesis in preparing mutants of a strain--a producer of a new antibiotic batumin].

Various plasmids carrying transposon Tn5 were used to generate insertion mutants synthesizing batumin, a unique antibiotic with a selective antistaphylococcal effect. One of the plasmids used provided a sufficient yield of the clones in question. An analysis of over 7000 clones allowed us to select the mutant clones with increased and decreased levels of batumin synthesis and the mutants that lost the ability to synthesize this antibiotic.

[Isolation of highly active strain producing the antistaphylococcal antibiotic batumin].

The use of chemical and UV-induced mutageneses allowed us to increase the biosynthetic activity of the strain capable of producing new antistaphylococcal antibiotic, batumin. The strain of Pseudomonas batumici N17 producing 87-100 mg batumin per liter culture liquid was selected. Its activity was 3.

Specific chromosome alterations in fluconazole-resistant mutants of Candida albicans.

The exposure of Candida albicans to fluconazole resulted in the nondisjunction of two specific chromosomes in 17 drug-resistant mutants, each obtained by an independent mutational event. The chromosomal changes occurred at high frequencies and were related to the duration of the drug exposure. The loss of one homologue of chromosome 4 occurred after incubation on a fluconazole medium for 7 days.

[The genetic aspects of the study of Pseudomonas syringae bacteria].

The work is a review of the state-of-art of molecular-genetic examination of bacteria P. syringae. The questions concerning new approaches to the study of determinants of pathogenicity, endogenic plasmids, toxins, resistance to antibiotics, avirulence, genes and insertion sequence elements of P.

[The plasmids of Pseudomonas syringae].

The paper deals with occurrence of plasmids in P. syringae strains belonging to seventeen pathovars: the strains were isolated in the USSR and other countries. One to four different plasmids having molecular weights of 20 to 90 Md have been found in various strains of the following twelve pathovars: holci, cerasi, aptata, tabaci, populi, pisi, lupini syringae, lachrymans, phaseolicola, glycinea, atrofaciens.