文献类型：期刊文献

英文题名：Ectoine and 5-hydroxyectoine accumulation in the halophile Virgibacillus halodenitrificans PDB-F2 in response to salt stress

作者：Tao, Ping[1];Li, Hui[1];Yu, Yunjiang[2];Gu, Jidong[3];Liu, Yongdi[1]

机构：[1]E China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, State Key Lab Biol Reactor Engn, Sch Resource & Environm Engn, Shanghai 200237, Peoples R China;[2]South China Inst Environm Sci, Ctr Environm Hlth Res, Guangzhou 510535, Guangdong, Peoples R China;[3]Univ Hong Kong, Swire Inst Marine Sci, Sch Biol Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China

年份：2016

卷号：100

期号：15

起止页码：6779

外文期刊名：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录：;EI(收录号：20161802312297);WOS:【SCI-EXPANDED(收录号:WOS:000379317300022)】；

基金：This work was supported jointly by the National Natural Science Foundation of China (51578240, 51378208, and 41273109), Specialized Research Fund for the Doctoral Program of Higher Education (20110074130002), Program for New Century Excellent Talents in University (NCET-13-0797), Innovation Program of Shanghai Municipal Education Commission (14ZZ059), and Fundamental Research Funds for the Central Universities (222201313008). We would like to thank the anonymous referees for their helpful comments regarding this paper.

语种：英文

外文关键词：Halophilic bacteria; Compatible solutes; Ectoine; Hydroxyectoine; ectABC; ectD

摘要：The moderately halophilic bacterium Virgibacillus halodenitrificans PDB-F2 copes with salinity by synthesizing or taking up compatible solutes. The main compatible solutes in this strain were ectoine and hydroxyectoine, as determined by H-1 nuclear magnetic resonance spectroscopy (H-1-NMR). A high-performance liquid chromatography (HPLC) analysis showed that ectoine was the major solute that was synthesized in response to elevated salinity, while hydroxyectoine was a minor solute. However, the hydroxyectoine/ectoine ratio increased from 0.04 at 3% NaCl to 0.45 at 15% NaCl in the late exponential growth phase. A cluster of ectoine biosynthesis genes was identified, including three genes in the order of ectA, ectB, and ectC. The hydroxyectoine biosynthesis gene ectD was not part of the ectABC gene cluster. Reverse transcription-quantitative polymerase chain reactions (RT-qPCR) showed that the expression of the ect genes was salinity dependent. The expression of ectABC reached a maximum at 12 % NaCl, while ectD expression increased up to 15 % NaCl. Ectoine and hydroxyectoine production was growth phase dependent. The hydroxyectoine/ectoine ratio increased from 0.018 in the early exponential phase to 0.11 in the stationary phase at 5 % NaCl. Hydroxyectoine biosynthesis started much later than ectoine biosynthesis after osmotic shock, and the temporal expression of the ect genes differed under these conditions, with the ectABC genes being expressed first, followed by ectD gene. Increased culture salinity triggered ectoine or hydroxyectoine uptake when they were added to the medium. Hydroxyectoine was accumulated preferentially when both ectoine and hydroxyectoine were provided exogenously.