Stimulants and donors promote megaplasmid pND6-2 horizontal gene transfer in activated sludge  

作　　者：Shan Wang Shanshan Li Dan Du Olusegun KAbass Muhammad Salman Nasir Wei Yan 

机构地区：[1]Department of Environmental Science and Engineering,Xi’an Key Laboratory of Solid Waste Recycling and Resource Recovery,Xi’an Jiaotong University,Xi’an 710049,China [2]School of Civil and Environmental Engineering,Nanyang Technological University,Singapore 639798,Singapore [3]Department of Structures and Environmental Engineering,University of Agriculture,Faisalabad 38040,Pakistan

出　　处：《Journal of Environmental Sciences》2023年第4期742-753,共12页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No. 31670512);Natural Science Basic Research Plan in Shaanxi Province of China(No. 2018JM3039)。

摘　　要：The activated sludge process is characterized by high microbial density and diversity,both of which facilitate antibiotic resistance gene transfer.Many studies have suggested that antibiotic and non-antibiotic drugs at sub-inhibitory concentrations are major inducers of conjugative gene transfer.The self-transmissible plasmid pND6-2 is one of the endogenous plasmids harbored in Pseudomonas putida ND6,which can trigger the transfer of another co-occurring naphthalene-degrading plasmid pND6-1.Therefore,to illustrate the potential influence of stimulants on conjugative transfer of pND6-2,we evaluated the effects of four antibiotics (ampicillin,gentamycin,kanamycin,and tetracycline) and naphthalene,on the conjugal transfer efficiency of pND6-2 by filter-mating experiment.Our findings demonstrated that all stimulants within an optimal dose promoted conjugative transfer of pND6-2from Pseudomonas putida GKND6 to P.putida KT2440,with tetracycline being the most effective (100μg/L and 10μg/L),as it enhanced pND6-2-mediated intra-genera transfer by approximately one hundred-fold.Subsequently,seven AS reactors were constructed with the addition of donors and different stimulants to further elucidate the conjugative behavior of pND6-2 in natural environment.The stimulants positively affected the conjugal process of pND6-2,while donors reshaped the host abundance in the sludge.This was likely because stimulant addition enhanced the expression levels of conjugation transfer-related genes.Furthermore,Blastocatella and Chitinimonas were identified as the potential receptors of plasmid pND6-2,which was not affected by donor types.These findings demonstrate the positive role of sub-inhibitory stimulant treatment on pND6-2 conjugal transfer and the function of donors in re-shaping the host spectrum of pND6-2.

关 键 词：ANTIBIOTICS NAPHTHALENE DONOR Conjugative transfer Host range 

分 类 号：X172[环境科学与工程—环境科学] R446.5[医药卫生—诊断学]