Peter Setlow

Spores of bacteria of Bacillus species are extraordinarily resistant to all manner of harsh treatments, and largely because of this resistance, spores of some Bacillus species are major agents of food spoilage and food-borne and other diseases (eg-Bacillus anthracis). The conversion of a dormant Bacillus spore into a vegetative bacterium by the process of spore germination is also a relatively simple differentiating system that is readily amenable to both biochemical and genetic analysis. While much has been learned in recent years on the mechanisms of spore resistance and germination, there is still much that is unknown. Dr. Setlow's laboratory has ongoing multidisciplinary research projects attempting to determine: 1) the mechanisms involved in the extraordinary resistance of spores to heat and oxidizing agents; 2) the mechanism(s) of spore germination and its heterogeneity; and 3) the structure and organization of the inner membrane of spores. Methods used in these projects include: 1) molecular biology to make directed mutants in key spore genes; 2) confocal fluorescence spectroscopy to localize and co-localize proteins in spores; 3) determination of structures of key spore germination and resistance proteins by X-ray crystallography; 4) classical genetics to identify new genes important in aspects of spore germination and resistance; 5) identify new factors important in spore resistance; 6) determine the mechanism(s) whereby moist heat, the most commonly used method to kill spores, actually works to kill spores; and 7) determine factors responsible for the extreme heterogeneity in spore germination such that while most spores in populations germinate within 30 min of addition of a germinant, a small percentage of spores may not germinate for hours or even days.

[2026] Two new factors modulating Bacillus subtilis spore resistance and germination. [2026] Structural and functional analysis of the Bacillus cereus GerI inosine-responsive spore germinant receptor. [2025] Effects of sporulation times in liquid or on plates on Bacillus subtilis spore resistance, germination, inner membrane fluidity and permeability, and core contents. [2025] Resistance and germination of spores of Bacillus species lacking members of a spore integral inner membrane protein family and locations of these proteins in spores. [2025] Pathways for accelerated bacterial spore killing with ohmic heating. [2025] Modeling heterogeneity, commitment, and memory of bacterial spore germination. [2025] Germination of Bacillus spores by LiCl. [2025] GerAB residues predicted to interfere