title: Expression level of Bacillus subtilis germinant receptors determines the average rate but not the heterogeneity of spore germination.
abstract: Germination of Bacillus subtilis spores can be triggered by the binding of specific nutrients, called germinants, to germinant receptors (GRs) in the spore's inner membrane. This interaction eventually initiates, with variable time delays, the release of dipicolinic acid and cations from the spore core--a key step in spore germination. The kinetics of this process are highly heterogeneous for individual spores. In this work, we sought to investigate how the germination heterogeneity was controlled. In particular, we tested whether the rates of germination were determined by GR levels, which vary from spore to spore due to stochastic gene expression. Both the expression levels of GRs and the germination rate were measured in single spores, and the experimental results were compared to theoretical predictions. Our results indicated that the variation in the expression levels of GRs was not the primary factor that controls spore germination heterogeneity. Two alternative hypotheses are discussed in light of this experimental discovery.
authors: Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT, USA.
authors: Jing-qiao
authors: JQ
authors: Zhang
authors: Keren K
authors: KK
authors: Griffiths
authors: Ann
authors: A
authors: Cowan
authors: Peter
authors: P
authors: Setlow
authors: Ji
authors: J
authors: Yu
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D010848:Picolinic Acids; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D013171:Spores, Bacterial; D013269:Stochastic Processes; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D010848:Picolinic Acids; D011956:Receptors, Cell Surface; C004860:dipicolinic acid
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