Helical shape and wall synthesis in a bacterium

Abstract

THE main skeletal components of most bacterial cell walls are complex polymers called peptidoglycans1. The primary chemical structures of these and other wall components are well understood but little is known about the arrangement of the molecules in the wall or how new wall material is incorporated during growth1. We report here that several factors cause cells of Bacillus subtilis, normally straight rods (Fig. 1b–e), to assume a regular helical shape. We suggest a model for the structure and synthesis of Gram positive cell walls which could explain these observations. Explanations suggested by Mendelson2 for an apparently different type of helical growth in B. subtilis do not account for our results.