MOLECULAR-CLONING OF THE RECA GENE OF PRO PIONIBACTERIUM-SHERMANII INESCHERICHIA-COLI

Propionibacterium are producers of vitamin B-12 and organic acids and are of-importance in national economy. Genetics of this organism was s tudied unsufficiently. We constructed the genomic library of Propionib acterium shermanii in cells of Escherichia coli using the plasmid vect or pVZ361 and identified recA gene. The vector gives a chance for dire ct selection of Str-resistant clones containing an insert in BamHI sit e. The recombinant plasmid carrying the recA gene of P. shermanii was isolated from the genomic library using complementation in E. coli. St rains E. coli C600 and HB101 were transformed by hybrid plasmids, and UV-light-resistant clones were identified. The clones were purified an d subjected to treatment with 4-NQO and MMS. Diagrams reflecting survi val dependence of die bacteria carrying recombinant plasmids and lacki ng them on the mutagen concentration and UV-light dose clearly confirm ed functioning of P. shermanii recA gene in E. coli cells. The insert with recA gene underwent restriction analysis. The 1.7 kb fragment wit h recA gene was then transferred to pBI101 plasmid and the resultant r ecombinant plasmid was used in the SOS test. The mutagens (MMS, 4-NHQ) and UV-light induced the SOS response in E. coli HB101 (recA) carryin g the recombinant plasmid.