[Antimutagenic action of bacterial culture liquid on mutagenesis induced by 2-nitrofluorene in Salmonella typhimurium strains].

It was shown that cell extracts and cells of Streptococcus faecalis decrease the mutagenic effect of 2-nitrofluorene in Salmonella typhimurium strain TA1538 by 73 and 48%, respectively. Cell extracts and cells of Bifidobacterium bifidum and Propionibacterium shermanii exhibited weak antimutagenic activity. No antimutagenic effect was found in Escherichia coli AB1157, Lactobacillus delbrueckii, or Streptococcus thermophilus. Antimutageneicity of the cell extract of Str. faecalis is both associated with extracellular factors interacting with 2-nitrofluorene (desmutagenesis) and with factors affecting intracellular processes of mutagen biotransformation and mutation induction. Thiol compounds produced by growing Str. faecalis may be desmutagenic factors. A relatively heat-stable substance or substances of a peptide nature with a MM less than 12 kDa are antimutagenic factors affecting intracellular processes of mutagenesis.