Key Laboratory of Land Resources Evaluation and Monitoring in Southwest (Sichuan Normal Universty), Ministry of Education, 610101, Chengdu, Sichuan, PR China; College of Life Science, Sichuan Normal University, 610101, Chengdu, Sichuan, PR China.
Key Laboratory of Land Resources Evaluation and Monitoring in Southwest (Sichuan Normal Universty), Ministry of Education, 610101, Chengdu, Sichuan, PR China.
Environ Res. 2023 Nov 1;236(Pt 1):116680. doi: 10.1016/j.envres.2023.116680. Epub 2023 Jul 25.
Microbial degradation of pesticide residues has the potential to reduce their hazards to human and environmental health. However, in some cases, degradation can activate pesticides, making them more toxic to microbes. Here we report on the β-cypermethrin (β-CY) toxicity to Bacillus cereus GW-01, a recently described β-CY degrader, and effects of antioxidants on β-CY degradation. GW-01 exposed to β-CY negatively affected the growth rate. The highest maximum specific growth rate (μ) appeared at 25 mg/L β-CY. β-CY induced the oxidative stress in GW-01. The activities of superoxide dismutase (SOD), catalyse (CAT), and glutathione-S-transferase (GST) were significantly higher than that in control (p < 0.01); but they are decreased as growth phase pronged, which is contrary to the β-CY degradation by GW-01 cells obtaining from various growth phase. Ascorbic acid (Vc), tea polyphenols (TP), and adenosine monophosphate (AMP) improved the degradation through changing the physiological property of GW-01. TP and AMP prompted the expression of gene encoding β-CY degradation in GW-01, while Vc does the opposite. Biofilm formation was significantly inhibited by β-CY, while was significantly enhanced by certain concentrations of TP and AMP (p < 0.05); while cell surface hydrophobicity (CSH) was negatively associated with β-CY concentrations from 25 to 100 mg/L, and these 4 antioxidants all boosted the CSH. Cells grown with β-CY had lower levels of saturated fatty acids but increased levels of some unsaturated and branched fatty acids, and these antioxidants alleviated the FA composition changes and gene expression related with FA metabolism. We also mined transcriptome analyses at lag, logarithmic, and stationary phases, and found that β-CY induced oxidative stress. The objective of this study was to elaborate characteristics in relation to the microbial resistance of pesticide poisoning and the efficiency of pesticide degradation, and to provide a promising method for improving pesticide degradation by microbes.
微生物对农药残留的降解具有降低其对人类和环境健康危害的潜力。然而，在某些情况下，降解会使农药激活，使其对微生物更具毒性。在这里，我们报告了拟除虫菊酯（β-CY）对 recently described β-CY degrader（GW-01）的毒性，以及抗氧化剂对β-CY 降解的影响。GW-01 暴露于 β-CY 会对其生长速率产生负面影响。在 25mg/L β-CY 时，最大比生长速率（μ）最高。β-CY 诱导 GW-01 产生氧化应激。超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽-S-转移酶（GST）的活性明显高于对照（p<0.01）；但随着生长阶段的延长而下降，这与 GW-01 细胞从不同生长阶段获得的 β-CY 降解相反。抗坏血酸（Vc）、茶多酚（TP）和单磷酸腺苷（AMP）通过改变 GW-01 的生理特性来提高降解。TP 和 AMP 促进了 GW-01 中编码 β-CY 降解的基因的表达，而 Vc 则相反。生物膜形成被 β-CY 显著抑制，而一定浓度的 TP 和 AMP 则显著增强（p<0.05）；而细胞表面疏水性（CSH）与 25 至 100mg/L 的 β-CY 浓度呈负相关，这 4 种抗氧化剂都增强了 CSH。用 β-CY 培养的细胞中饱和脂肪酸水平较低，但某些不饱和和支链脂肪酸水平较高，这些抗氧化剂缓解了与 FA 代谢相关的 FA 组成变化和基因表达。我们还对滞后、对数和静止阶段的转录组分析进行了挖掘，发现β-CY 诱导了氧化应激。本研究的目的是阐述与农药中毒微生物抗性和农药降解效率相关的特征，并为提高微生物降解农药的效率提供一种有前途的方法。
