Hunan Key Lab of Green Packaging and Biological Nanotechnology, Hunan University of Technology, Zhuzhou 412007, People's Republic of China.
Curr Microbiol. 2012 Dec;65(6):799-804. doi: 10.1007/s00284-012-0224-2. Epub 2012 Sep 21.
Heavy metal resistance microorganism plays an important role on polluted soil bioremediation. To obtain further knowledge of the resistant mechanism employed by cadmium-resistant bacteria, some gene expression profiles at transcription level were investigated in P. aeruginosa E(1) subjected to cadmium stress using real-time PCR. Exposure to cadmium for 1 h, the expression of czcA, czcB, and czcC all reached the peak of up-regulation 8.82-, 4.83-, and 7.43-fold, respectively. The response of czcD was earlier and stronger than czcABC. CysM contributed to cysteine synthesis kept up-regulation within the beginning 2 h. The expression of mgtAE genes related to Mg(2+) influx was up-regulated all the while, znuB responsible for Zn(2+) transportation kept up-regulation from 30 min to 4 h. The result support the two cadmium-resistance mechanisms including effluxing and inactive the heavy metal ions. The mechanism was brought that increase of Mg(2+) and Zn(2+) in cytoplasm would prevent Cd(2+)-binding enzymes to decrease the harm to cell.
重金属抗性微生物在污染土壤的生物修复中起着重要作用。为了进一步了解耐镉细菌所采用的抗性机制，采用实时 PCR 技术研究了铜绿假单胞菌 E(1)在镉胁迫下转录水平的一些基因表达谱。在镉暴露 1 h 时，czcA、czcB 和 czcC 的表达均达到了 8.82、4.83 和 7.43 倍的上调峰值。czcD 的反应比 czcABC 更早更强。CysM 有助于半胱氨酸合成，在最初的 2 小时内保持上调。与 Mg(2+)流入相关的 mgtAE 基因的表达一直上调，负责 Zn(2+)运输的 znuB 从 30 分钟到 4 小时保持上调。结果支持了两种包括外排和使重金属离子失活的镉抗性机制。该机制表明，细胞质中 Mg(2+)和 Zn(2+)的增加会阻止 Cd(2+)-结合酶的活性，从而降低对细胞的伤害。
