Liu Lin, Yu Xin, Wu Daizhuo, Su Jianqiang
Key Laboratory of Urban Pollutant Conversion, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Key Laboratory of Urban Pollutant Conversion, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Pollut. 2022 Jul 1;304:119221. doi: 10.1016/j.envpol.2022.119221. Epub 2022 Mar 28.
Antibiotic resistance gene (ARG) pollution is critical environmental problem, and horizontal gene transfer acts as a driving evolutionary force. In theory, due to the phylogenetic distance between eukaryotes and prokaryotes, eukaryotic microalgae can be a natural barrier that plays a negative role in ARG transfer among the symbiotic bacteria to decrease ARG abundance in sludge during wastewater treatment. However, this hypothesis is far from proven and needs to be tested experimentally, so this study investigated the influence of eukaryote microalgae (Scenedesmus) on the ARG profile of symbiotic bacteria based on aerobic granular reactor. The results indicated that Scenedesmus symbiosis could affect ARG diversity of bacteria, and the detected numbers of ARG in aerobic granular sludge (AG) group and algae-bacteria granular consortia (AAG) group were 45-53 and 44-47, respectively. In terms of relative abundance, after target microalgae symbiosis, the total abundance of ARGs significantly decreased from 1.17 × 10°, 2.69 × 10° and 1.36 × 10 to 6.53 × 10, 9.64 × 10 and 1.04 × 10 in the systems with the addition of streptomycin, azithromycin and vancomycin, respectively (P < 0.05), yet there was no significant difference between AG and AAG under the stress of ampicillin, sulfamethazine and tetracycline (P > 0.05). Redundancy analysis showed that the eukaryotic microalgae were significant factor explaining the change in ARG relative abundance (P < 0.05), which contributed 15.3% of ARG variation. Furthermore, the results show that, except for the tetracycline treatment system, the total relative abundances of MGEs in the AAG under the stress of the other five antibiotics were 3.54 × 10-7.13 × 10, which were all significantly lower than those in the AG (8.38 × 10-1.59 × 10°). There was a more significant positive correlation relationship between ARGs and mobile genetic elements (MGEs) than that between ARGs and dominated bacteria.
抗生素抗性基因（ARG）污染是一个严峻的环境问题，水平基因转移是其进化的驱动力量。理论上，由于真核生物和原核生物之间的系统发育距离，真核微藻可以成为一种天然屏障，对共生细菌之间的ARG转移起到负面作用，从而在废水处理过程中降低污泥中ARG的丰度。然而，这一假设远未得到证实，需要通过实验进行验证，因此本研究基于好氧颗粒污泥反应器，研究了真核微藻（栅藻）对共生细菌ARG谱的影响。结果表明，栅藻共生会影响细菌的ARG多样性，好氧颗粒污泥（AG）组和藻菌颗粒联合体（AAG）组中检测到的ARG数量分别为45 - 53种和44 - 47种。在相对丰度方面，目标微藻共生后，在添加链霉素、阿奇霉素和万古霉素的系统中，ARG的总丰度分别从1.17×10°、2.69×10°和1.36×10显著降至6.53×10、9.64×10和1.04×10（P < 0.05），但在氨苄青霉素、磺胺二甲嘧啶和四环素胁迫下，AG和AAG之间没有显著差异（P > 0.05）。冗余分析表明，真核微藻是解释ARG相对丰度变化的重要因素（P < 0.05），贡献率为15.3%。此外，结果表明，除四环素处理系统外，在其他五种抗生素胁迫下，AAG中移动遗传元件（MGE）的总相对丰度为3.54×10 - 7.13×10，均显著低于AG中的（8.38×10 - 1.59×10°）。ARG与移动遗传元件（MGE）之间的正相关关系比ARG与优势细菌之间的更为显著。
