Proteomic responses of spores of Bacillus subtilis to thermosonication involve large-scale alterations in metabolic pathways.

Thermosonication (TS) impacts numerous characteristics of spores, such as morphology, cell metabolism, and stress resistance. However, relevant mechanisms need to be clarified. In the present study, the effect of TS treatment on Bacillus subtilis spores was investigated at phenotypic and proteomic levels. The results showed that TS treatment induced significant changes to spores in growth kinetics and morphology. A total of 167 differentially expressed proteins (DEPs) were obtained after TS treatment at 6.67 W/mL and 80 °C. Among these proteins, 80 were up-regulated, whereas 87 were down-regulated. These DEPs were classed into 20 functional categories. Enrichment analysis of the proteome revealed that the major categories were associated with metabolic functions, including energy metabolic processes, amino acids biosynthesis and metabolism, translation and ribosomal protein. In summary, B. subtilis spores showed alteration primarily in the proteins that were associated with metabolism under TS treatment. These findings could be applied to the development and optimization of TS-based sporicidal treatment.