ANTIMUTAGENIC ACTIVITY OF BACTERIAL-CELL EXTRACTS ON MUTAGENESIS INDUCED BY 2-NITROFLUORENE IN STRAINS OF SALMONELLA-TYPHIMURIUM

It was shown that cell extracts and cells of Streptococcus faecalis de crease the mutagenic effect of 2-nitrofluorene in Salmonella typhimuri um strain TA1538 by 73 and 48%, respectively. Cell extracts and cells of Bifido-bacterium bifidum and Propionibacterium shermanii exhibited weak antimutagenic activity. No antimutagenic effect was found in Esch erichia coli AB1157, Lactobacillus delbrueckii, or Streptococcus; ther mophilus. Antimutagenicity of the cell extract of Str. faecalis is bot h associated with extracellular factors interacting with 2-nitrofluore ne (desmutagensis) and with factors affecting intracellular processes of mutagen biotransformation and mutation induction. Thiol compounds p roduced by growing Str. faecalis may be desmutagenic factors. A relati vely heat-stable substance or substances of a peptide nature with a MM less than 12 kDa are antimutagenic factors affecting intracellular pr ocesses of mutagenesis.