摘要
      本研究报告了不同类型（gyrAR、tetAR、qnrSR）和构象形式（染色体，质粒）的ARGs和可移动遗传元件（intl-1，质粒）在紫外线和紫外线/H2O2处理下作为水基质（DI水、磷酸盐缓冲液、废水）的函数的降解动力学的结构化研究。追踪细胞外、细胞内和游离ARGs的命运，以推断各种参数对处理过程降解效果的影响。e-ARGs的降解谱（118–454 bp）显示出1-4个对数的减少，但与扩增子大小没有强烈的相关性，这表明活性位点分布和/或ARGs类型对紫外线诱导的基因损伤的重要性。与e-ARGs相比，i-ARGs在磷酸盐缓冲液（PBS）中对UV的降解速率相似，但由于细胞成分清除自由基dotOH自由基，用UV/H2O2对i-ARGs-s的降解速率较慢（1.3–2倍）。虽然ARB失活是有效的，但由于i-ARG和f-ARG持续存在，ARG损伤不是补充性的。在废水基质中，自由基物种的产生有助于提高UV/H2O2处理的降解率，特别是f-ARGs，与PBS相比，降解率显著提高（p<0.05）。这表明紫外线照射对流出物有机物（EfOM）产生的自由基物种的攻击具有非选择性性质，而不是紫外线对基因的基于测序的损伤。对于质粒降解，与染色体ARGs相比，与超螺旋结构和细胞内形式有关的构象差异影响较慢（1.2–2.8倍）的紫外线介导的基因损伤率。这些结果可用于更好地评估基于紫外线的处理工艺，以有效去除ARG。
Abstract
This study reports a structured investigation on the degradation kinetics of different types (gyrAR, tetAR, qnrSR) and conformational forms (chromosomal, plasmids) of ARGs and mobile genetic elements (intl-1, plasmids) as a function of water matrix (DI water, phosphate buffer, wastewater) with UV and UV/H2O2 treatments. Extracellular, intracellular and the free-ARGs fate were tracked to infer the impact of various parameters on the degradation efficacy of the treatment process. The degradation profile of e-ARGs (118–454 bp) showed 1–4 log reductions but did not correlate strongly to amplicon size indicating the importance of active sites distribution and/or types of ARGs for UV induced gene damage. The i-ARGs showed similar degradation rates compared to e-ARGs for UV in phosphate buffer (PBS) but showed (1.3–2 times) slower rates for i-ARGs with UV/H2O2 due to scavenging of radical dotOH radicals by the cellular components. While the ARB inactivation was effective, but ARG damage was not supplemental as i-ARGs and f-ARGs persisted. In the wastewater matrix, generation of radical species was contributing to improved degradation rates from UV/H2O2 treatment, specifically for f-ARGs resulting in significantly improved degradation (p < 0.05) compared to PBS. These indicates a non-selective nature of attack from radical species generated from UV irradiation on the effluent organic matter (EfOM) than sequenced based damage to the genes from UV. For the plasmid degradation, conformational differences pertaining to the supercoiled structures and intracellular forms influenced slower (1.2–2.8 times) UV mediated gene damage rate as opposed to chromosomal ARGs. These results can be useful for better assessing UV based treatment processes for effective ARG removal.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722022987