Plasmids of Crystal-forming Bacilli and the Influence of Growth Medium Composition on their Appearance

Abstract

Bacillus subtilis mutant 1000M, derived from strain A-50, can form proteinaceous crystalline inclusions at a frequency of 1-2%. This mutant also has a higher sporulation ability and reduced levels of intra- and extracellular serine protease activity compared with its parent strain. Mutant 1000M carries plasmids, the quantity of plasmid material isolated being dependent on the composition of the growth medium. Comparable data were also found for typical crystal-forming bacteria (B. thuringiensis).