Deciphering the mechanisms for preferential tolerance of Escherichia coli BL21 to Cd(II) over Cu(II) and Ni(II): A combined physiological, biochemical, and multiomics perspective

作者：Jackson Nkoh Nkoh, Ting Ye, Chenjing Shang, Chunyuan Li, Jing Tu, Sihui Li, Zuping Wu, Pengyu Chen, Quaid Hussain, Seraphine Nkie Esemu · 发表于：Ecotoxicology and Environmental Safety · 年份：2025 · DOI：10.1016/j.ecoenv.2025.118195 · 被引用次数：4 · 研究领域：Heavy metals in environment、Trace Elements in Health、Chromium effects and bioremediation

Environmental pollution severely affects ecological functions/health, and nondegradable pollutants such as heavy metals (HMs) cause significant damage to living organisms. Escherichia coli is one of the most studied life forms, and its response to oxidative stress is driven by a complex ensemble of mechanisms driven by transcriptomic-level adjustments. However, the magnitude of the physiological, metabolic, and biochemical alterations and their relationships with transcriptomic changes remain unclear. Studying the growth of E. coli in Cd-, Cu-, and Ni-polluted media at pH 5.0, we observed that (i) downregulation of the alkyl hydroperoxide complex, glutathione reductase, and glutathione S-transferase by Cd inhibited H 2 O 2 degradation, and the accumulated H 2 O 2 was respectively 2.7, 1.7, and 2.4 times greater than that in the control, Cu, and Ni treatments; (ii) Zn-associated resistance protein (ZraP) was the major scavenger of Cd, with a 140.7-fold increase in its expression; (iii) the P-type Cu + transporter (CopA), multicopper oxidase (CueO), and heteromultimeric transport system (CusCBAF) controlled the excretion and detoxification of Cu; (iv) the Cd 2+ /Zn 2+ /Pb 2+ -exporting P-type ATPase (ZntA) and transcriptional activator ZntR were the major transporters of Ni; (v) Cd upregulated biofilm formation and synthesis of secondary metabolites more than Cu and Ni, which resulted in increased adsorption and improved tolerance; and (vi) the activity of superoxide dismutase ...