Liu Yuan, Qiu Yanlun, Yin Qi, Li Xinglong, Bai Qunhua, Li Yingli, Xiao Hong
Department of Health Laboratory Technology, School of Public Health and Management, Chongqing Medical University, No. 1 Yixueyuan Road, Yuzhong District, Chongqing 400016, China; Center for Disease Control and Prevention, Chongqing 400010, China.
Center for Disease Control and Prevention, Beibei District, Chongqing 400700, China.
Ecotoxicol Environ Saf. 2021 Nov 22;228:112899. doi: 10.1016/j.ecoenv.2021.112899.
Serratia sp. CM01 is a wild strain with the resistance and reduction ability of chromium(Ⅵ). The aim of this study it to investigate the underlying mechanisms of the Cr(Ⅵ) tolerance and reduction of strain CM01, and to explore its response to environmental pollution pressure at the molecular level.
The iTRAQ technique was utilized to investigate the differentially expressed protein patterns related to the Cr(Ⅵ)-resistance in wild-type strain CM01 and domesticated CM01. RT-qPCR was used to verify the expression levels of several functional genes. The cell surface hydrophobicity and autoaggregation, the intracellular glucose content, and the total superoxide dismutase (SOD) activity were determined.
In total, 2750 proteins were detected and identified in WT CM01 and domesticated CM01. Compared with WT CM01, the iTRAQ results of 646 proteins were found to be significantly differentially expressed in domesticated CM01. There were 343 up-regulated and 303 down-regulated proteins, which mainly related to carbohydrate metabolism, stress responses, amino acid metabolism and some other systems. RT-qPCR results showed that the expression level of seven genes in domesticated CM01 were consistent with the iTRAQ proteomic profiles. The cell surface hydrophobicity, self-aggregation, intracellular glucose content and total SOD activity of domesticated CM01 with Cr(Ⅵ) treatment were significantly higher than without Cr(Ⅵ) treatment.
Domesticated CM01 displayed a complex biological network to exhibit the tolerance of Cr(Ⅵ), which may be attributed to the following aspects: (a) CM01 reduced the consumption of glucose by inhibiting the metabolism of carbohydrates, which was an energy-saving survival mode. (b) The inositol phosphate metabolism pathway played an important role. (c) Oxidative stress proteins enhanced the adaptability. (d) CM01 enhanced biosynthesis of hydrophobic amino acids to resistance to Cr(Ⅵ). (e) Several key systems and proteins, such as UvrABC system, Lon protease, porin OmpC, also may play an important role.
粘质沙雷氏菌CM01是一株具有铬（Ⅵ）抗性及还原能力的野生菌株。本研究旨在探究CM01菌株对Cr（Ⅵ）耐受及还原的潜在机制，并在分子水平上探索其对环境污染压力的响应。
采用iTRAQ技术研究野生型菌株CM01和驯化后的CM01中与Cr（Ⅵ）抗性相关的差异表达蛋白质模式。利用RT-qPCR验证几个功能基因的表达水平。测定细胞表面疏水性和自聚集性、细胞内葡萄糖含量以及总超氧化物歧化酶（SOD）活性。
在野生型CM01和驯化后的CM01中总共检测并鉴定出2750种蛋白质。与野生型CM01相比，在驯化后的CM01中发现646种蛋白质的iTRAQ结果存在显著差异表达。其中有343种蛋白质上调，303种蛋白质下调，主要涉及碳水化合物代谢、应激反应、氨基酸代谢及其他一些系统。RT-qPCR结果表明，驯化后的CM01中7个基因的表达水平与iTRAQ蛋白质组学图谱一致。经Cr（Ⅵ）处理的驯化后CM01的细胞表面疏水性、自聚集性、细胞内葡萄糖含量和总SOD活性显著高于未经Cr（Ⅵ）处理的情况。
驯化后的CM01展现出一个复杂的生物网络以表现出对Cr（Ⅵ）的耐受性，这可能归因于以下几个方面：（a）CM01通过抑制碳水化合物代谢减少葡萄糖消耗，这是一种节能的生存模式。（b）肌醇磷酸代谢途径发挥了重要作用。（c）氧化应激蛋白增强了适应性。（d）CM01增强疏水氨基酸的生物合成以抵抗Cr（Ⅵ）。（e）几个关键系统和蛋白质，如UvrABC系统、Lon蛋白酶、孔蛋白OmpC，也可能发挥重要作用。
