Turnover and Excretion of Streptococcal Surface Components

Abstract

The dynamic nature of bacterial cell surface components is a major factor in their relationship to the immune system. The processes of bacterial growth and division require expansion of cell surface area while maintaining the protective properties of the wall in order to contain internal osmotic pressures of as much as 20 atmospheres (1). Furthermore, the bacterial wall must protect its protoplast from adverse, or at least non-supportive, conditions that bacterial cells may meet in the intermittently changing environments in vivo in which they can survive, and sometimes grow. Obviously, these physiological parameters vary with bacterial species and probably contribute to the type of microbial flora found in the various ecological niches of the body, including the oral cavity. In addition, the ability of streptococci to continue to synthesize and excrete biologically active substances when they are exposed to environments that do not support balanced growth has implications particularly relevant to the “feast or famine” type of environment present in the oral cavity. Currently, little information is available on the kinds and amounts of extracellular products produced in vivo. Although conditions found in vivo cannot be exactly duplicated, the effects of some of the potentially important variables on surface components and extracellular products can be individually studied in the test tube.