Clostridium perfringens spore germination: characterization of germinants and their receptors.

TitleClostridium perfringens spore germination: characterization of germinants and their receptors.
Publication TypeJournal Article
Year of Publication2008
AuthorsParedes-Sabja D, Torres AJ, Setlow P, Sarker MR
JournalJournal of bacteriology
Date Published2008 Feb
KeywordsAlanine, Asparagine, Bacterial Proteins, Chromosomes, Bacterial, Clostridium perfringens, Dose-Response Relationship, Drug, Gene Expression Regulation, Bacterial, Genes, Bacterial, Models, Genetic, Mutation, Operon, Plasmids, Potassium Chloride, Protons, Reverse Transcriptase Polymerase Chain Reaction, Spores, Bacterial, Temperature, Valine

Clostridium perfringens food poisoning is caused by type A isolates carrying a chromosomal enterotoxin (cpe) gene (C-cpe), while C. perfringens-associated non-food-borne gastrointestinal (GI) diseases are caused by isolates carrying a plasmid-borne cpe gene (P-cpe). C. perfringens spores are thought to be the important infectious cell morphotype, and after inoculation into a suitable host, these spores must germinate and return to active growth to cause GI disease. We have found differences in the germination of spores of C-cpe and P-cpe isolates in that (i) while a mixture of L-asparagine and KCl was a good germinant for spores of C-cpe and P-cpe isolates, KCl and, to a lesser extent, L-asparagine triggered spore germination in C-cpe isolates only; and (ii) L-alanine or L-valine induced significant germination of spores of P-cpe but not C-cpe isolates. Spores of a gerK mutant of a C-cpe isolate in which two of the proteins of a spore nutrient germinant receptor were absent germinated slower than wild-type spores with KCl, did not germinate with L-asparagine, and germinated poorly compared to wild-type spores with the nonnutrient germinants dodecylamine and a 1:1 chelate of Ca2+ and dipicolinic acid. In contrast, spores of a gerAA mutant of a C-cpe isolate that lacked another component of a nutrient germinant receptor germinated at the same rate as that of wild-type spores with high concentrations of KCl, although they germinated slightly slower with a lower KCl concentration, suggesting an auxiliary role for GerAA in C. perfringens spore germination. In sum, this study identified nutrient germinants for spores of both C-cpe and P-cpe isolates of C. perfringens and provided evidence that proteins encoded by the gerK operon are required for both nutrient-induced and non-nutrient-induced spore germination.

Alternate JournalJ. Bacteriol.