[Role of serodiagnosis in recognizing atypical forms of leptospirosis in Krasnodar Territory]. / Rol' serodiagnostiki v raspoznavanii atipichnykh form leptospirozov v Krasnodarskom krae.

The work deals with the epidemiological situation with respect to Leptospira infections in the Krasnodar territory. The work demonstrates that, in comparison with 1960-ies characterized by the prevalence of diseases caused by L. pomona and L. grippotyphosa, in 1970-ies the increase of the specific proportion of infections caused by L. icterohaemorrhagiae was registered. In recent 5 years (1980-1984) this leptospirosis constituted 73.5-94.8% of the total morbidity rate in the territory. Such situation was caused by active prophylactic measures in cattle breeding, as well as by the increase of the number of leptospirosis foci, appearing as the result of human activities and providing favorable conditions for the life and multiplication of Norway rats, the main source of infection caused by L. icterohaemorrhagiae as indicated by the fact that up to 23.9% of the Norway rats examined in this study proved to be contaminated. The detection of cases of leptospirosis among febrile patients and mistakes in clinical diagnosis confirm the necessity of the serological examination of febrile patients with the acute onset of the disease with temperature reaching 38 degrees C and higher for 3-5 days and the clinical picture of the disease being unclear in order to find out patients presenting with the atypical clinical picture of leptospirosis.

[Characteristics of RecA-independent recombination of plasmids in E. coli cells producing restriction endonuclease EcoRI]. / Osobennosti RecA-nezavisimoi rekombinatsii plazmid v kletkakh E. coli, produtsiruiushchikh éndonukleazu restriktsii EcoRI.

The restriction endonuclease EcoRI dependent recombination of compatible plasmids has been studied in RecA cells of Escherichia coli. Plasmid RP4 and the isogenic ColE1 type plasmids pSA14 or pSA25, differing in restriction-modification RM EcoRI genes, have been used to study this type of recombination. EcoRI dependent recombination of plasmids is demonstrated in RecA cells and, thus, is independent of general system of homologous recombination. The classes of recombinant plasmids isolated from RecA cells differ from the classes isolated from wild type cells. Levels of tetracycline resistance conferred by plasmid RP4 are shown to be dependent on the alleles of RecA+ gene, being extremely low in RecA cells. This property is demonstrated to be useful for obtaining the multicopy recombinant plasmids resulting from EcoRI dependent recombination in RecA cells of Escherichia coli.

[Plasmid recombination stimulated by restriction endonuclease EcoRI in vivo: formation of recombinant plasmids in recA+-cells of E. coli]. / Rekombinatsiia plazmid, stimuliruemaia éndonukleazoi restriktsii EcoRI in vivo: formirovanie rekombinantnykh plazmid v recA+-kletkakh E. coli.

The possible participation of restriction endonuclease EcoRI in recombination of compatible nonhomologous plasmids in E. coli cells has been studied. To study the process, plasmids RP4 and R245 have been transferred by conjugation into the recipient cells of E. coli harbouring one of isogenic plasmids, pSA14 and pSA25, different for the genes coding restriction endonuclease EcoRI. The genetic analysis of transconjugant phenotypes, coded by the plasmids, has permitted to register the recombinant plasmids after compatibility of parent plasmids in E. coli cells. Recombination of plasmid RP4 with the plasmid pSA14, carrying EcoRI genes, has been registered in E. coli cells, producing the restriction endonuclease, while plasmid recombination has not been found in the cells harbouring plasmid pSA25, isogenic for all genes, except for EcoRI genes, with plasmid pSA14. Restriction endonuclease EcoRI is concluded to stimulate site specific recombination of nonhomologous compatible plasmids in vivo. EcoRI-mediated recombination of plasmid R245 with plasmid pSA14 is discussed.