Juan Wen, Norbert O E Vischer, Arend L de Vos, Erik M M Manders, Peter Setlow, Stanley Brul | Sci Rep. 2022 Mar 23;12(1):4944. doi: 10.1038/s41598-022-09147-3
Summary
The SpoVA proteins form a channel in the inner membrane of Bacillus subtilis spores that releases Ca²⁺-DPA from the spore core during germination in response to activated germinant receptors.
In this study, the authors examined the location and behavior of SpoVAEa in dormant spores. Fluorescently labeled SpoVAEa-SGFP2 appeared as a single spot in the inner membrane, similar to the germinosome complex. Unlike the relatively fixed receptor complex, however, the SpoVAEa spot moved rapidly and randomly, which the authors suggest may help transmit germination signals to the SpoVA channel.
They also tracked SpoVAEa-SGFP2 and surrounding membrane regions during germination. Dormant spores contained an immobile membrane microdomain that disappeared as germination progressed. Loss of membrane dye fluorescence and peak SpoVAEa-SGFP2 intensity closely matched the rapid phase darkening associated with Ca²⁺-DPA release.
Heat treatment between 40°C and 80°C increased green autofluorescence, likely linked to coat protein denaturation. At 80°C, phase-grey-like spores also appeared, suggesting a germination-like internal state without the ability to complete germination.
Overall, the findings provide new insight into membrane dynamics and signaling during bacterial spore germination.
Read the publication: https://pubmed.ncbi.nlm.nih.gov/35322191