恩诺沙星残留对土壤中固氮细菌固氮基因(nifH)多样性的影响

为了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微生物固氮酶nifH基因的分子多样性进行了分析。结果表明,恩诺沙星作用于土壤后第35天,Ⅰ-Ⅵ组的OTUs与克隆子的百分比分别为:34.31%、32.18%、26.04%、20.83%、19.09%、20.00%;第70天,Ⅰ-Ⅵ组的OTUs与克隆子的百分比分别为:23.85%、20.75%、18.26%、16.67%、14.58%、11.67%。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(P0.05),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-Wiener指数与其他添加药物组差异均显著,第70天,仅与10μg/g和50μg/g两组差异显著。由此可见,随着药物作用的时间延长,药物含量0.01-1μg/g组土壤固氮微生物的多样性与对照组之间的差异变小。

Effects of enrofloxacin on molecular diversity of nitrogenase reductase genes (nifH)

The experiment was aimed to investigate the effects of ENR (enrofloxacin) on microbial community diversity in soil. The molecular diversity and community structure of nitrogen-fixing microbes were analyzed by PCR-based cloning and RFLP (restriction fragment length polymorphism) approach. PCR-RFLP analysis revealed that the percentages of OTUs to total clones among groups I to VI were 34.31%, 32.18%, 26.04%, 20.83%, 19.09% and 20.00%, respectively after 35 days' incubation, and that the percentages of them were 23.85%, 20.75%, 18.26%, 16.67%, 14.58% and 11.67% after 70 days' incubation, respectively. The effects of ENR on molecular diversity of nitrogen-fixing microbial communities were enhanced with the increasing ENR concentrations. The results showed that the Margalef Index in CK was significantly ( P < 0.05) higher than that in the soils in which ENR was added after 35 days. However, the Margalef Index in CK was only significantly higher than that in the soils treated with 10 g/g and 50 g/g of ENR after 70 days, respectively.As for the Shannon-Wiener Indexes, CK was significantly higher than those in the groups treated with ENR except for 0. 01 g/g after 35 days. The Shannon-Wiener Indexes were the same as Margalef Indexes after 70 days. It was indicated that the effects of ENR on molecular diversity of nitrogen-fixing microbial communities in the treated groups with ENR at the concentrations of 0. 01 g/g to 1 g/g were not significantly distinguished from that of CK with the increasing of treatment time.