摘要

      环境系统中的流动抗生素耐药基因（ARGs）可能对公众健康构成威胁。共存的取代芳香族污染物可能有助于ARGs穿过胞外聚合物（EPS）渗透屏障进入细胞内，促进ARG的扩散，但其作用机制尚不清楚。在这里，我们证明了在细胞外基质中的移动质粒的一种特殊的抗水解机制对这种便利的传播做出了更大的贡献。特别地，用Tb3+标记的pUC19质粒荧光微量滴定法研究了与ARG播散相关的取代芳香族质粒复合物的形成。对endA基因和EPS的操作证实了这些形成的复合物对抗EPS介导的质粒水解。傅立叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）和计算化学表明，取代基改变了芳香族分子的极性，使1,3-二氯苯的6位碳和间苯二胺、苯胺和2-萘酚的不稳定质子（-NH2/-OH）相互作用磷酸根的脱质子羟基（P-O···H-C/N/O），主要通过氢键作用。ARG扩散、缔合常数和键能之间的线性相关性突出了ARG增殖对d-核糖-磷酸模板的功能组合的定量依赖性。

       Mobile antibiotic resistance genes (ARGs) in environmental systems may pose a threat to public health. The coexisting substituted aromatic pollutants may help the ARGs cross the extracellular polymeric substance (EPS) permeable barrier into the interior of cells, facilitating ARG dissemination, but the mechanism is still unknown. Here, we demonstrated that a specific antihydrolysis mechanism of mobile plasmid in the extracellular matrix makes a greater contribution to this facilitated dissemination. Specifically, fluorescence microtitration with a Tb³⁺-labeled pUC19 plasmid was used to study the formation of substituted aromatic-plasmid complexes associated with ARG dissemination. Manipulations of the endA gene and an EPS confirmed that these forming complexes antagonize the EPS-mediated hydrolysis of the plasmid. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and computational chemistry demonstrated that substituents alter the polarity of aromatic molecules, making the carbon at the 6-position of 1,3-dichlorobenzene as well as the labile protons (-NH₂/-OH) of m-phenylenediamine, aniline, and 2-naphthol interact with the deprotonated hydroxy group of the phosphate (P-O···H-C/N/O), mainly via hydrogen bonds. Linear correlations among ARG disseminations, association constants, and bonding energies highlight the quantitative dependency of ARG proliferation on a combination of functionalities templated by d-ribose-phosphate.

       https://pubs.acs.org/doi/10.1021/acs.est.8b05750