大型溞对水环境中抗生素抗性菌与抗性基因的摄食与去除

原后生动物是污水生物处理系统中的常见生物，了解它们是否能够摄食与去除抗生素抗性菌（ARB）和抗生素抗性基因（ARGs），对于建立藉捕食作用的ARB和ARGs去除技术具有重要意义.本研究以大型溞作为代表生物，探究了其对ARB和ARGs的摄食、去除效果与机制.使用荧光抗性菌直接观察其摄食过程，证实大型溞对ARB的摄食与富集.分析了溶液中和肠道中的ARB数目及drfA基因丰度变化，发现大型溞对ARB的摄食过程符合一级动力学；不同ARB浓度会影响大型溞的摄食及去除效果，在高ARB浓度下具有较高的过滤速率和滤食速率；大型溞的摄食减少了试验体系中的drfA基因丰度，检测到大型溞肠道内的DNA酶，其可能是导致其丰度减少的原因.

Ingestion and digestion of antibiotic resistance bacteria and genes by Daphnia in water

Zooplankton is commonly found in biological wastewater treatment process. It is very important to know if they can ingest and reduce the antibiotic resistance genes (ARGs) and antibiotic resistance bacteria (ARB) in order to develop biological predation and removal method of ARB and ARGs. So that, Daphnia magna (D. magna) was used as a representative species and its predatory process and removal mechanism for ARB and ARGs were studied. The genetically modified ARB E. coli MG1655 with a fluorescent protein gene which allows directly microscopic observation of feeding process was used. Hence the uptake of ARB by D. magna was evidenced and confirmed. Changes of ARB concentrations and drfA gene abundance were analyzed to determine the grazing kinetics. It was found that the ARB concentrations affected the filter-feeding process which follows first-order kinetics. At high ARB concentration, D. magna has higher filtering rate and grazing rate of ARB. The abundance of drfA gene decreased by the grazing process of D. magna. The DNase activity in the gut matters of D. magna was detected which probably catalyzed the digestion of ARGs.