Yin Qun-Jian, Zhang Wei-Jia, Qi Xiao-Qing, Zhang Sheng-Da, Jiang Ting, Li Xue-Gong, Chen Ying, Santini Claire-Lise, Zhou Hao, Chou I-Ming, Wu Long-Fei
Laboratory of Deep-sea Microbial Cell Biology, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Microbiol. 2018 Jan 9;8:2646. doi: 10.3389/fmicb.2017.02646. eCollection 2017.
High hydrostatic pressure (HHP) exerts severe effects on cellular processes including impaired cell division, abolished motility and affected enzymatic activities. Transcriptomic and proteomic analyses showed that bacteria switch the expression of genes involved in multiple energy metabolism pathways to cope with HHP. We sought evidence of a changing bacterial metabolism by supplying appropriate substrates that might have beneficial effects on the bacterial lifestyle at elevated pressure. We isolated a piezosensitive marine bacterium strain QY27 from the South China Sea. When trimethylamine -oxide (TMAO) was used as an electron acceptor for energy metabolism, QY27 exhibited a piezophilic-like phenotype with an optimal growth at 30 MPa. Raman spectrometry and biochemistry analyses revealed that both the efficiency of the TMAO metabolism and the activity of the TMAO reductase increased under high pressure conditions. Among the two genes coding for TMAO reductase catalytic subunits, the expression level and enzymatic activity of TorA was up-regulated by elevated pressure. Furthermore, a genetic interference assay with the CRISPR-dCas9 system demonstrated that TorA is essential for underpinning the improved pressure tolerance of QY27. We extended the study to type strain ATCC33809 and observed the same phenotype of TMAO-metabolism improved the pressure tolerance. These results provide compelling evidence for the determinant role of metabolism in the adaption of bacteria to the deep-sea ecosystems with HHP.
高静水压（HHP）对细胞过程产生严重影响，包括细胞分裂受损、运动性丧失和酶活性受影响。转录组学和蛋白质组学分析表明，细菌会切换参与多种能量代谢途径的基因表达，以应对高静水压。我们通过提供可能对高压下细菌生存方式有有益影响的合适底物，来寻找细菌代谢变化的证据。我们从中国南海分离出一株对压力敏感的海洋细菌菌株QY27。当三甲胺氧化物（TMAO）用作能量代谢的电子受体时，QY27表现出嗜压样表型，在30兆帕时生长最佳。拉曼光谱和生物化学分析表明，在高压条件下，TMAO代谢效率和TMAO还原酶活性均增加。在编码TMAO还原酶催化亚基的两个基因中，TorA的表达水平和酶活性因压力升高而上调。此外，使用CRISPR-dCas9系统进行的基因干扰试验表明，TorA对于增强QY27的耐压性至关重要。我们将研究扩展到模式菌株ATCC33809，观察到TMAO代谢改善耐压性的相同表型。这些结果为代谢在细菌适应具有高静水压的深海生态系统中的决定性作用提供了有力证据。
