Involvement of Calcium in Germination of Coat‐Modified Spores of Bacillus cereus T

Abstract

The effect of calcium on germination of coat-modified Bacillus cereus T spores was investigated. Coat-modified spores produced either by chemical extraction (SDS-DTT-treated spores) or by mutagenesis (10LD mutant spores) were unable to germinate in response to inosine. While SDS-DTT-treated spores could germinate slowly in the presence of L-alanine, l OLD mutant spores could not germinate at all. The lost or reduced germinability of coat-modified spores was restored when exogenous Ca2+ was supplemented to the germination media. The calcium requirement of coat-modified spores for germination was fairly specific. The simultaneous presence of germinant with Ca2+ was also required for germination of coat-modified spores. The optimal recovery of germinability was obsei ved in the presence of 1.0 mm of calcium acetate. The calcium requirement itself was remarkably diminished under the condition in which L-alanine and a certain purine nucleoside analog, adenosine or inosine, coexisted. The lost or diminished germinability observed in SDS-DTT-treated spores or l OLD mutant spores may be attributed to the loss of calcium associated with the spore integuments.

The Presence of Low Molecular Weight Germinative Substances in Bacillus cereus T Spore Extract

“…On the other hand, Ca2+ is required to germinate the sensitized spores of B. cereus T for inosineinduced germination (13). The present result in Fig.…”

“…Unless otherwise indicated, all germination assays were performed by using spores sensitized as described previously (13,14), because permeability barriers of intact spores might obstruct the germinal response with an exogenously added large molecule. In this assay system, a spore extract (1 ml), a non-diffusible fraction (1 ml), a diffusible fraction (0.7 ml), a deproteinized diffusible fraction (0.5 ml) and samples from HPLC (1 ml) were routinely examined for their germination-inducing activities.…”

Cyanobacterial formation of intracellular Ca‐carbonates in undersaturated solutions

“…() determined a maximum uptake of 0.8–1.2 mg of calcium per g of dry matter for the cyanobacterium Gloeocapsa sp. Spores of Bacillus cereus and Bacillus megaterium , which are notorious for being highly enriched in Ca, accumulate 14–23 mg/g of Ca (Foerster & Foster, ; Shibata, Miyoshi, Osato, Tani, & Hashimoto, ). Overall, this suggests that strains of intracellular carbonate‐forming cyanobacteria tend to accumulate Ca to a larger extent than other strains, although this should be measured systematically for many other cyanobacterial strains.…”

Development of novel Alicyclobacillus spp. isolation medium

“…Short exposure to calcium in starvation medium was enough for the cells to respond and sporulate, suggesting that early essential calcium‐dependent functions occur during sporulation induction. Shibata et al. (1992) suggests that the calcium involved in germination is associated with the spore coat instead of the core.…”