Nguyen Huyen Thi Minh, Akanuma Genki, Hoa Tu Thi Minh, Nakai Yuji, Kimura Keitarou, Yamamoto Kazutaka, Inaoka Takashi
Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Institute of Biotechnology, Vietnam Academy of Science and Technology, Ha Noi, Viet Nam.
Appl Environ Microbiol. 2019 Dec 13;86(1). doi: 10.1128/AEM.01640-19.
Vegetative cells of can recover from injury after high-hydrostatic-pressure (HHP) treatment at 250 MPa. DNA microarray analysis revealed that substantial numbers of ribosomal genes and translation-related genes (e.g., translation initiation factors) were upregulated during the growth arrest phase after HHP treatment. The transcript levels of cold shock-responsive genes, whose products play key roles in efficient translation, and heat shock-responsive genes, whose products mediate correct protein folding or degrade misfolded proteins, were also upregulated. In contrast, the transcript level of , whose product (Hpf) is involved in ribosome inactivation through the dimerization of 70S ribosomes, was downregulated during the growth arrest phase. Sucrose density gradient sedimentation analysis revealed that ribosomes were dissociated in a pressure-dependent manner and then reconstructed. We also found that cell growth after HHP-induced injury was apparently inhibited by the addition of Mn or Zn to the recovery medium. Ribosome reconstruction in the HHP-injured cells was also significantly delayed in the presence of Mn or Zn Moreover, Zn, but not Mn, promoted dimer formation of 70S ribosomes in the HHP-injured cells. Disruption of the gene suppressed the Zn-dependent accumulation of ribosome dimers, partially relieving the inhibitory effect of Zn on the growth recovery of HHP-treated cells. In contrast, it was likely that Mn prevented ribosome reconstruction without stimulating ribosome dimerization. Our results suggested that both Mn and Zn can prevent ribosome reconstruction, thereby delaying the growth recovery of HHP-injured cells. HHP treatment is used as a nonthermal processing technology in the food industry to inactivate bacteria while retaining high quality of foods under suppressed chemical reactions. However, some populations of bacterial cells may survive the inactivation. Although the survivors are in a transient nongrowing state due to HHP-induced injury, they can recover from the injury and then start growing, depending on the postprocessing conditions. The recovery process in terms of cellular components after the injury remains unclear. Transcriptome analysis using vegetative cells of revealed that the translational machinery can preferentially be reconstructed after HHP treatment. We found that both Mn and Zn prolonged the growth-arrested stage of HHP-injured cells by delaying ribosome reconstruction. It is likely that ribosome reconstruction is crucial for the recovery of growth ability in HHP-injured cells. This study provides further understanding of the recovery process in HHP-injured cells.
的营养细胞在250兆帕的高静水压（HHP）处理后能够从损伤中恢复。DNA微阵列分析表明，大量核糖体基因和翻译相关基因（如翻译起始因子）在HHP处理后的生长停滞阶段被上调。冷休克反应基因（其产物在高效翻译中起关键作用）和热休克反应基因（其产物介导正确的蛋白质折叠或降解错误折叠的蛋白质）的转录水平也被上调。相反，其产物（Hpf）通过70S核糖体二聚化参与核糖体失活的基因的转录水平在生长停滞阶段被下调。蔗糖密度梯度沉降分析表明，核糖体以压力依赖的方式解离然后重建。我们还发现，向恢复培养基中添加锰或锌会明显抑制HHP诱导损伤后的细胞生长。在存在锰或锌的情况下，HHP损伤细胞中的核糖体重建也显著延迟。此外，锌而非锰促进了HHP损伤细胞中70S核糖体的二聚体形成。基因的破坏抑制了锌依赖性核糖体二聚体的积累，部分缓解了锌对HHP处理细胞生长恢复的抑制作用。相反，锰可能在不刺激核糖体二聚化的情况下阻止核糖体重建。我们的结果表明，锰和锌都能阻止核糖体重建，从而延迟HHP损伤细胞的生长恢复。HHP处理在食品工业中用作非热加工技术，以灭活细菌，同时在抑制化学反应的情况下保持食品的高质量。然而，一些细菌细胞群体可能在灭活过程中存活下来。尽管由于HHP诱导的损伤，幸存者处于短暂的非生长状态，但它们可以从损伤中恢复，然后根据后处理条件开始生长。损伤后细胞成分方面的恢复过程仍不清楚。使用的营养细胞进行的转录组分析表明，翻译机制在HHP处理后可以优先重建。我们发现，锰和锌都通过延迟核糖体重建延长了HHP损伤细胞的生长停滞阶段。核糖体重建可能对HHP损伤细胞生长能力的恢复至关重要。这项研究进一步加深了对HHP损伤细胞恢复过程的理解。
