Initiation of Germination in Bacillus and Clostridium Spores
from: Bacterial Spores: Current Research and Applications (Edited by: Ernesto Abel-Santos). Caister Academic Press, U.K. (2012)
Dormant bacterial spores of the genera Bacillus and Clostridium employ receptors belonging to the GerA family as environmental sensors. The recognition and binding of appropriate small molecule ligands, termed germinants, irreversibly commits the spore to initiate the cascade of biophysical and hydrolytic reactions that comprise the germination process. Germination is a crucial event in the lifecycle of spore forming organisms, since in virtually all cases the detrimental properties associated with the bacterium are manifested during vegetative growth. However, despite intensive research spanning several decades, few details concerning the precise function of the nutrient germinant receptors (other than their ability to trigger spore germination in response to specific germinants) or the molecular mechanisms that underpin the earliest stages of the process, are known. The current chapter describes genetic, structural and functional aspects of spore germinant receptors, highlighting diverse functional roles and mechanistic strategies associated with GerA-type receptors. Indeed, present outputs from mutational and bioinformatic analyses seem to support the notion that, whereas the general mechanism of triggering germination may be largely conserved between Bacillus and Clostridium species, a number of different mechanisms involving GerA-type receptor proteins, and perhaps unrelated proteins, also exist, and are employed by at least by some pathogenic Clostridium read more ...