State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
Sci Adv. 2021 Mar 26;7(13). doi: 10.1126/sciadv.abf9941. Print 2021 Mar.
High hydrostatic pressure (HHP) is a characteristic environmental factor of the deep ocean. However, it remains unclear how piezotolerant bacteria adapt to HHP. Here, we identify a two-step metabolic pathway to cope with HHP stress in a piezotolerant bacterium. D25, obtained from a deep-sea sediment, can take up trimethylamine (TMA) through a previously unidentified TMA transporter, TmaT, and oxidize intracellular TMA into trimethylamine -oxide (TMAO) by a TMA monooxygenase, Tmm. The produced TMAO is accumulated in the cell, functioning as a piezolyte, improving both growth and survival at HHP. The function of the TmaT-Tmm pathway was further confirmed by introducing it into and Encoded TmaT-like and Tmm-like sequences extensively exist in marine metagenomes, and other marine Bacteroidetes bacteria containing genes encoding TmaT-like and Tmm-like proteins also have improved HHP tolerance in the presence of TMA, implying the universality of this HHP tolerance strategy in marine Bacteroidetes.
高静压（HHP）是深海的一个特征环境因素。然而，目前尚不清楚耐压细菌如何适应 HHP。在这里，我们确定了一种两步代谢途径来应对耐压细菌中的 HHP 应激。从深海沉积物中获得的 D25 可以通过以前未鉴定的 TMA 转运蛋白 TmaT 摄取三甲胺（TMA），并通过 TMA 单加氧酶 Tmm 将细胞内 TMA 氧化成三甲胺氧化物（TMAO）。产生的 TMAO 在细胞内积累，起到压稳剂的作用，提高了在 HHP 下的生长和存活能力。TmaT-Tmm 途径的功能通过将其引入 和 进一步得到证实。编码 TmaT 样和 Tmm 样序列广泛存在于海洋宏基因组中，并且含有编码 TmaT 样和 Tmm 样蛋白的其他海洋拟杆菌细菌在存在 TMA 的情况下也提高了 HHP 耐受性，这表明这种 HHP 耐受策略在海洋拟杆菌中具有普遍性。
