Sporulation and spore properties of Bacillus brevis and its gramicidin S-negative mutant

The function(s) of the peptide antibiotic, gramicidin S, in its producer, Bacillus brevis Nagano, was investigated. Particular attention was paid to the possible role of gramicidin S in sporulation and spore properties. Sporulation was similar in both the gramicidin S-producing parental strain and a gramicidin S-negative mutant of this strain. Mature parental and mutant spores were equally resistant to UV irradiation, solvents (reported previously) and heat. Thus, the lack of gramicidin S synthesis impairs none of these properties. Contrary to results reported by others, we also found no difference in heat resistance between spores of B. brevis ATCC 8185 and its linear gramicidin-negative mutant, Ml.