Divalent Cation Signaling in Clostridium perfringens Spore Germination.

Spore germination plays an essential role in the pathogenesis of Clostridium perfringens-associated food poisoning. Germination is initiated when bacterial spores sense various stimuli, including chemicals and enzymes. A previous study showed that dipicolinic acid (DPA) chelated with calcium (Ca-DPA) significantly stimulated spore germination in C. perfringens. However, whether Ca²⁺ or DPA alone can induce germination is unknown. Therefore, we aimed to evaluate the possible roles of Ca²⁺ and other divalent cations present in the spore core, such as Mn²⁺ and Mg²⁺, in C. perfringens spore germination. Our study demonstrated that (i) Ca-DPA, but not DPA alone, induced C. perfringens spore germination, suggesting that Ca²⁺ might play a signaling role; (ii) all tested calcium salts induced spore germination, indicating that Ca²⁺ is critical for germination; (iii) the spore-specific divalent cations Mn²⁺ and Mg²⁺, but not Zn²⁺, induced spore germination, suggesting that spore core-specific divalent cations are involved in C. perfringens spore germination; and (iv) endogenous Ca²⁺ and Mg²⁺ are not required for induction of C. perfringens spore germination, whereas exogenous and partly endogenous Mn²⁺ are required. Collectively, our results suggest that exogenous spore core-specific divalent cation signals are more important than endogenous signals for the induction of spore germination. [ABSTRACT FROM AUTHOR]