Helical growth and macrofiber formation of Bacillus subtilis 168 autolytic enzyme deficient mutants

Abstract

Two poorly lytic, chain-forming mutants of B. subtilis 168, strains FJ3 and FJ6, each 90-95% deficient in the production of N-acetylmuramoyl-L-alanine amidase and endo-.beta.-N-acetylglucosaminidase, grew helically under a variety of cultural conditions. The structures formed ranged in complexity from double-stranded helices to complex aggregates of entangled and interwoven single chains and multistranded helical fibers. Factors favoring this type of helical growth were investigated. Occasional tight single-stranded corkscrewlike forms were detected in the mutant cultures. Two other poorly lytic mutant strains of Bacillus were also found to have helical growth capacity. These results were interpreted as support for the recently proposed tension restricted helical growth model of Mendelson.