| 微塑料及金属在黄浦江地表水环境的赋存特征及与金属抗性基因的相关性分析 |
| 摘要点击 3228 全文点击 2219 投稿时间：2022-06-23 修订日期：2022-08-03 |
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| 中文关键词 微塑料(MPs) 金属 金属抗性基因(MRGs) 可移动遗传元件(MGEs) 宏基因组学 |
| 英文关键词 microplastic(MPs) metals metal resistance genes (MRGs) mobile genetic elements (MGEs) metagenomics |
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| 中文摘要 |
| 城市河流是微塑料（MPs）及重金属污染的"热点"区域，在污染迁移中起到重要作用.然而同样作为抗性基因赋存及释放的重要媒介，鲜有研究考察了流域MPs、金属与金属抗性基因（MRGs）的关联.为此，调研了10个黄浦江站点水样的金属及MPs的污染特征，并基于宏基因组学对水样及提取的MPs上的MRGs及可移动遗传元件（MGEs）进行分析.结果显示，表层水中ρ［锑（Sb）］平均值最高，为（3.16±0.419）μg ·L-1.MPs的丰度平均值为（1.78±0.84） n ·L-1，位于工业区和人口密集区的MPs丰度显著高于农业区和低人口密度的区域.纤维状、"小粒径"（<0.5 mm）的聚对苯二甲酸乙二醇酯（PET）是最主要的MPs类型.所有样本中共检出18类MRGs，其中水样中MRGs的相对丰度为1.68±0.21.最主要的MRGs亚型是merR和ruvB，分别为汞和多重金属抗性基因的亚型.相关性分析表明，水中的铬和镍与MRG-Cr、MRG-Ni和多重金属抗性基因之间存在显著正相关.MPs上MRGs的相对丰度为1.63±0.53，最主要的MRGs亚型是merT-P和copB，同样为汞和多重金属抗性基因的亚型.其中多重金属抗性基因亚型ctpC、cueA、czrA和kmtR等与水中的Ni、Cr和Sb含量都存在显著正相关.与水样相比，MPs选择性富集merT-P、copB、ziaA、sodA和dmeF.此外，基于网络分析挖掘了MRGs和MGEs的共现模式.在水环境中，MRGs可经由转座子 tnpA_1和tnpA_2 ，整合子qacEdelta及插入序列 IS91 实现水平基因转移，使微生物产生对应金属的抗性.MPs表面多重金属抗性基因和铜的抗性基因与质粒的亚型IncFIC （FII）、 Rep7、rep7和rep13 之间存在显著正相关，MPs的存在对由质粒介导的特定MRGs的水平基因转移有着显著影响. |
| 英文摘要 |
| Urban rivers have been regarded as the "hotspots" for microplastic (MPs) and metal contamination as they play important roles in pollution migration. However, as important sinks and sources of resistance genes, there has been little to no research investigating the associations between MPs, metal contaminations, and metal resistance genes (MRGs). Ten water samples were collected from the Huangpu River in situ; along with metal elements, MPs characteristics analyzed. Metal resistance genes and mobile genetic elements (MGEs) in waters and MPs were detected using metagenomic technology. As a result, the highest metal concentration was that of Sb in surface water (3.16±0.419) μg·L-1. The average abundance of MPs was (1.78±0.84) n·L-1, and the peak levels located in industrial and densely populated areas, which was significantly higher than those in agricultural and low population density areas. Fibrous, small-size (<0.5 mm), and transparent polyethylene terephthalate (PET) were the largest contributors of MPs. Eighteen MRGs were detected in all the samples. The relative abundance of MRGs in water was 1.68±0.21. The most dominant MRGs subtypes were merR and ruvB, which are subtypes resistant to mercury and Multi_metals. Correlation analysis showed that chromium and nickel in waters were significantly positively associated with MRG-Cr, MRG-Ni, and Multi_metals resistance genes. For MPs particles, the relative abundance of MRGs was 1.63±0.53. The most dominant MRGs subtypes were merT-P and copB, which also belong to mercury-resistant and Multi_metals. The Multi_metals resistance gene, ctpC, cueA, czrA, kmtR, etc., had significant positive associations with Ni, Cr, and Sb in waters. Compared with water samples, MPs selectively enriched merT-P, copB, ziaA, sodA, and dmeF. Additionally, the co-occurrence patterns of MRGs and MGEs were explored based on network analysis. In water samples, the transposases (tnpA_1 and tnpA_2), integrase (qacEdelta), and insertion sequence (IS91) were the major contributors of the horizontal gene transfer (HGT) of specific MRGs. Multiple subtypes resistant to copper and Multi_metals resistance genes on MPs were positively associated with IncFIC(FII), Rep7, rep7, and rep13, which were subtypes of plasmids. The presence of MPs exerted a significant impact on HGT of specific MRGs mediated by plasmids. |
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