Singh Shyam K, Samaranayake Chaminda P, Korza George, Ali Mohamed M, Setlow Peter, Sastry Sudhir
The Ohio State University, Columbus, OH, USA.
University of California, Davis, CA, USA.
NPJ Sci Food. 2025 Aug 7;9(1):167. doi: 10.1038/s41538-025-00537-1.
The mechanism by which ohmic heating (OH) accelerates bacterial spore killing compared to conventional heating (CH) is unclear. This study used genetically modified Bacillus subtilis spores to investigate OH's impact on specific components. Flow cytometry assessed membrane integrity, and molecular dynamics (MD) simulations examined the DNA-SASP complex under an electric field. Among the inner membrane (IM) proteins (YetF, YdfS, and YkjA) tested for its resistance against OH and CH, YeTF was found to be the most significant contributor to spore resistance for both treatments. SASP, SpoVA proteins, and Ca-DPA interacted with the field, showing specific effects at certain temperature and field intensity combinations. Flow cytometry showed spore staining with propidium iodide (PI), which increased with higher field intensities, indicating significant IM damage. MD simulations showed that the electric field caused the SASP-DNA complex to dissociate, with greater separation at higher field intensities. Thus, OH accelerates spore killing by affecting key IM and core molecules.
与传统加热（CH）相比，欧姆加热（OH）加速细菌芽孢杀灭的机制尚不清楚。本研究使用基因改造的枯草芽孢杆菌芽孢来研究OH对特定成分的影响。流式细胞术评估膜完整性，分子动力学（MD）模拟在电场下研究DNA-SASP复合物。在测试的内膜（IM）蛋白（YetF、YdfS和YkjA）对OH和CH的抗性中，发现YeTF是两种处理中芽孢抗性的最重要贡献者。SASP、SpoVA蛋白和Ca-DPA与电场相互作用，在特定温度和场强组合下显示出特定效应。流式细胞术显示芽孢用碘化丙啶（PI）染色，随着场强增加而增加，表明IM有显著损伤。MD模拟表明电场导致SASP-DNA复合物解离，在较高场强下分离更大。因此，OH通过影响关键的IM和核心分子来加速芽孢杀灭。
