Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC.
Can J Microbiol. 2010 Apr;56(4):295-307. doi: 10.1139/w10-008.
Methanohalophilus portucalensis FDF1 can grow over a range of external NaCl concentrations, from 1.2 to 2.9 mol/L. Differential gene expression in response to long-term hyper-salt stress (3.1 mol/L of NaCl) and hypo-salt stress (0.9 mol/L of NaCl) were compared by differential display RT-PCR. Fourteen differentially expressed genes responding to long-term hyper- or hypo-salt stress were detected, cloned, and sequenced. Several of the differentially expressed genes were related to the unique energy-acquiring methanogenesis pathway in this organism, including the transmembrane protein MttP, cobalamin biosynthesis protein, methenyl-H4MPT cyclohydrolase and monomethylamine methyltransferase. One signal transduction histidine kinase was identified from the hyper-salt stress cultures. Moreover, 3 known stress-response gene homologues - the DNA mismatch repair protein, MutS, the universal stress protein, UspA, and a member of the protein-disaggregating multichaperone system, ClpB - were also detected. The transcriptional analysis of these long-term salt stress response and adaptation-related genes for cells immediately after salt stress indicated that the expression of the energy metabolism genes was arrested during hyper-salt shock, while the chaperone clpB gene was stimulated by both hypo- and hyper-salt shock.
泥沼甲烷八叠球菌 FDF1 可以在外部 NaCl 浓度范围内生长，从 1.2 到 2.9 mol/L。通过差异显示 RT-PCR 比较了长期高盐胁迫（3.1 mol/L NaCl）和低盐胁迫（0.9 mol/L NaCl）下的差异基因表达。检测到 14 个对长期高盐或低盐胁迫有反应的差异表达基因，并对其进行了克隆和测序。其中一些差异表达的基因与该生物中独特的获取能量的甲烷生成途径有关，包括跨膜蛋白 MttP、钴胺素生物合成蛋白、亚甲基-H4MPT 环水解酶和单甲基胺甲基转移酶。从高盐胁迫培养物中鉴定出一种信号转导组氨酸激酶。此外，还检测到 3 个已知的应激反应基因同源物 - DNA 错配修复蛋白 MutS、普遍应激蛋白 UspA 和蛋白去聚集多伴侣系统的一个成员 ClpB。对盐胁迫后立即的细胞进行这些长期盐胁迫反应和适应相关基因的转录分析表明，在高盐冲击期间，能量代谢基因的表达被阻断，而伴侣蛋白 clpB 基因受到低盐和高盐冲击的刺激。
