Inhibition of 4-nitroquinoline-1-oxide genotoxicity by Bacillus strains

The effect of 16 Bacillus strains from pharmaceutical probiotic preparations (Bacillus spp.) and collection (B. subtilis, B. firmus, B. megaterium, B. pumilus) on genotoxicity induced by the known mutagen 4-nitroquinoline-1-oxide (4-NQO) was studied using the short-term bacterial assay SOS-chromotest. with Escherichia coli PQ37 as the tester organism. It was found that the activity of 0.1 mM 4-NQO was reduced (P < 0.01) after coincubation with Bacillus suspensions (10(8) CFU/ml for 150 min at 37 degrees C). All isolates showed potential for deactivating 4-NQO, and genotoxicity inhibition ranged from 92.9 to 100%. There were no appreciable differences in behaviour observed among probiotic and collection strains or in relation to species. The observed antigenotoxicity was associated with a clear-cut modification of 4-NQO molecular characteristics.