摘要

       由于抗生素的过量使用，抗生素耐药基因（ARGs）成为水环境中普遍存在的污染物。石墨烯氧化物（GO）是一种新兴的二维纳米材料，在本研究中被用于潜在的ARG污染控制。系统研究了GOs与含卡那霉素抗性基因（aphA）质粒DNA的相互作用，并探讨了GOs对ARG转化的抑制作用。制备了4种不同侧向尺寸（1.0、0.60、0.17和0.08μm2）的GOs，并将其定义为GO1.0、GO0.60、GO0.17和GO0.08。结果表明，4种GOs均能有效插入质粒DNA，插入能力依次为：GO0.08 > GO0.17 > GO0.60 > GO1.0。基于圆二色性（CD）光谱分析，所有GOs均干扰了DNA的碱基堆积模式和双螺旋结构，与GOs的插层活性呈正相关。GO0.08在25μg/mL时，超螺旋质粒DNA被部分裂解，琼脂糖凝胶电泳观察到裂痕和线状结构。此外，GO质粒与DNA的相互作用抑制了aphA基因的扩增和转化，且随着GO浓度的增加和横向尺寸的减小，抑制作用增强。GO0.08（25μg/mL）对aphA转化的抑制率达50%。GOs与含ARGs质粒DNA的大小依赖性相互作用将有助于指导GOs减少细胞外ARG转化的环境应用。

        Due to excessive consumption of antibiotics, antibiotic resistance genes (ARGs) become a ubiquitous pollutant in aquatic environments. Graphene oxide (GO), an emerging 2D nanomaterial, was used for potential control of ARG contamination in the present work. We systematically investigated the interaction of GOs with Kanamycin resistance gene (aphA)-containing plasmid DNA, and related the inhibition of ARG transformation by GOs. Four GOs with different lateral sizes (1.0, 0.60, 0.17, and 0.08 μm²) were prepared, and defined as GO_1.0, GO_0.60, GO_0.17 and GO_0.08. It is found that all the four GOs could effectively intercalate into plasmid DNA, and the intercalation abilities followed the order: GO_0.08 > GO_0.17 > GO_0.60 > GO_1.0. Based on circular dichroism (CD) spectrum analysis, all GOs disturbed the base stacking mode and double helix structure of DNA, which is positively related to the intercalation activities of GOs. For GO_0.08 at 25 μg/mL, the supercoiled plasmid DNA was partially cleaved, and the nicked and linear structures were observed based on agarose gel electrophoresis analysis. Moreover, the amplification and transformation of aphA gene were both inhibited due to GO-plasmid DNA interactions, and the inhibition was stronger with increasing GO concentrations and smaller lateral sizes. The inhibition of aphA transformation after GO_0.08 (25 μg/mL) exposure achieved 50%. The size-dependent interaction of GOs with ARGs-containing plasmid DNA will be useful for guiding the environmental applications of GOs in reducing extracellular ARG transformation.

        https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(19)33882-3