Affiliation:
1. Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3305
Abstract
ABSTRACT
Spores of
Bacillus
species are said to be committed when they continue through nutrient germination even when germinants are removed or their binding to spores' nutrient germinant receptors (GRs) is both reversed and inhibited. Measurement of commitment and the subsequent release of dipicolinic acid (DPA) during nutrient germination of spores of
Bacillus cereus
and
Bacillus subtilis
showed that heat activation, increased nutrient germinant concentrations, and higher average levels of GRs/spore significantly decreased the times needed for commitment, as well as lag times between commitment and DPA release. These lag times were also decreased dramatically by the action of one of the spores' two redundant cortex lytic enzymes (CLEs), CwlJ, but not by the other CLE, SleB, and CwlJ action did not affect the timing of commitment. The timing of commitment and the lag time between commitment and DPA release were also dependent on the specific GR activated to cause spore germination. For spore populations, the lag times between commitment and DPA release were increased significantly in spores that germinated late compared to those that germinated early, and individual spores that germinated late may have had lower appropriate GR levels/spore than spores that germinated early. These findings together provide new insight into the commitment step in spore germination and suggest several factors that may contribute to the large heterogeneity among the timings of various events in the germination of individual spores in spore populations.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
125 articles.
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