Variation in the Chemical Composition of the Cell Walls of Bacillus subtilis during Growth in Different Media

Abstract

DURING recent years the chemical composition of the cell wall has been used as an aid in the classification of micro-organisms¹. Although differences in the composition of the cell wall have been demonstrated during growth of organisms with: (a) variable morphological forms²; (b) complex auxotrophic requirements³; (c) addition of D-amino-acids⁴, many investigations have not considered the variations which occur in the amino-acid and amino-sugar content of more stable stains of bacteria during the growth cycle and in response to different growth media. The results presented here demonstrate that the amino-acid and amino-sugar content of the cell wall of Bacillus subtilis varies not only with growth but is also significantly influenced by the composition of the growth medium. Furthermore, galactosamine, one of the major components of the cell wall of the highly transformable strain B. subtilus 168 I-C⁺, is consistently decreased when this strain is grown under conditions which do not permit the development of the capacity to bind deoxyribonucleic acid (competence). A marked decrease in galactosamine is also observed in three poorly transformable strains of B. subtilis.