Running the Gauntlet of the Bacterial Cell Wall

Abstract

In nature, bacteria have a variety of shapes, from simple cocci and rods to more complicated spiral or appendage structures. In their life, they need a strong exoskeleton that can maintain their shape during growth and protect them from changes in environmental conditions. This rigid structure is generally provided by the cell wall and is considered an essential component in the bacterial cell. However, the cell wall represents a complex logistical problem in terms of the controlled synthesis and degradation that is required to maintain shape, permit enlargement, and prevent lysis. Significant advances have been made in understanding wall synthesis, and in Gram-negative bacteria synthesis can be integrated with degradation. But, for Gram-positive bacteria the regulation of cell wall degradation is poorly characterised. Genetically the genes encoding the key enzymes are known and the expression of these enzymes are known to be highly regulated. However, understanding how the biochemical activity of these enzymes is restricted and regulated, presumably within the cell wall or on the outside surface of the cell is not clear. The results obtained in this laboratory have indicated that altered cell wall composition or media components modulate the level of the hydrolysis enzyme activity in some way during vegetive growth. This study aimed to extend our understanding of the autolytic systems and how the enzymatic activity may be regulated by components of the cell envelope or minor modifications of the cell wall material.