恩诺沙星残留对土壤中反硝化细菌氧化二氮还原酶基因(nosZ)多样性的影响

Effects of enrofloxacin on molecular diversity of nitrous oxide reductase genes (nosZ)

为了解恩诺沙星在环境中残留对土壤微生物的影响,通过PCR扩增、基因克隆、RFLP分析法对恩诺沙星影响下的土壤反硝化细菌氧化二氮还原酶nosZ基因的分子多样性进行了研究。结果表明,恩诺沙星作用于土壤后第35天,ⅠⅥ组(Ⅰ组0μg/g、Ⅱ组0.01μg/g、Ⅲ组0.1μg/g、Ⅳ组1μg/g、Ⅴ组10μg/g、Ⅵ组50μg/g)的OTUs与克隆子的百分比分别为:48.30%、41.88%、34.78%、33.62%、25.42%、23.81%;第70天,ⅠⅥ组的OTUs与克隆子的百分比分别为:29.66%、24.24%、18.10%、16.67%、15.83%、14.39%。对照组多样性指数均高于添加药物组,第35天,对照组的M argalef指数与添加药物各组差异均显著(P<0.05),第70天,仅与10μg/g和50μg/g两组差异显著;第35天,除了0.01μg/g组,对照组的Shannon-W iener指数与其他添加药物组差异均显著,第70天,仅与50μg/g组差异显著。由此可见,随着药物作用的时间延长,药物含量0.0110μg/g组土壤反硝化细菌的多样性与对照组之间的差异变小。

The experiment was aimed to investigate the effects of ENR（enrofloxacin） on microbial community diversity in soil.The molecular diversity of denitrifying bacteria was analyzed by PCR-based cloning and RFLP（restriction fragment length polymorphism） methods.PCR-RFLP analysis revealed that the percentages of OTUs to total clones among groups Ⅰ to Ⅵ（0,0.01,0.1,1,10μg/g and 50μg/g,respectively） were 48.30%,4 1.88%,34.78%,33.62%,25.42% and 23.81%,respectively after the ENR addition for 35 days,and that the percentages were 29.66%,24.24%,18.10%,16.67%,15.83% and 14.39% after the ENR addition for 70 days,respectively.The effects of ENR on diversity of denitrifying bacteria were enhanced with the increasing ENR concentrations.The results showed that the Margalef Index in CK was significantly（P〈0.05） higher than those from soils amended with ENR after 35 days.The Margalef Index in CK was only significantly higher than those in soils treated with 10 g/g and 50 g/g of ENR after 70 days,respectively.Shannon-Wiener Indexes in CK were significantly higher than those treated with ENR except 0.01 g/g after 35 days,but the Shannon-Wiener Index in CK was only significantly higher than that in the soils treated with 50 g/g of ENR after 70 days.Our data indicated that the effects of ENR on diversity of denitrifying bacteria in soils at lower concentrations（0.01 g/g to 10 g/g） were decreased with incubation time.