土霉素对扇形游仆虫(原生生物)种群生长及遗传多样性的影响  

Effects of Oxytetracycline on Population Growth and Genetic Diversity of Euplotes vannus(Marine Protist)

作　　者：付娆[1] 龚骏[1] 张倩倩[1] 

机构地区：[1]中国科学院烟台海岸带研究所微生物生态与物质循环实验室,烟台264003

出　　处：《中国科学：生命科学》2016年第9期1113-1120,共8页Scientia Sinica(Vitae)

基　　金：国家自然科学基金(批准号:41176143);山东省杰出青年基金项目(批准号:JQ201210)资助

摘　　要：抗生素作为一类环境污染物在海岸带生境中广泛存在,它们对海洋原生生物遗传多样性的影响还不清楚.本工作以一种海洋纤毛虫原生生物(扇形游仆虫(Euplotes vannus))为例,研究了一种常见四环类抗生素(土霉素)对其生长的影响,并通过单细胞(个体)分析,探索了抗生素对其大核基因组中核糖体小亚基RNA基因(SSU r DNA)序列多样性的影响.结果表明,与对照组相比,3个土霉素处理组(1,10和20μg/m L)中纤毛虫的自然增长率随土霉素浓度升高显著降低,细胞大小则呈增大趋势.SSU r DNA序列单倍型多样性、核苷酸多样性和GC含量随抗生素浓度升高呈现降低趋势.序列单核苷酸多态性位点的碱基转换频率远高于颠换,但随土霉素浓度升高,颠换频率呈增加趋势.在20μg/m L处理组中,SSU r DNA序列中胸腺嘧啶(T)突变为胞嘧啶(C)的频率显著升高,而腺嘌呤(A)突变为鸟嘌呤(G)的频率显著降低.这表明,海岸带抗生素污染对纤毛虫表型与生理产生显著影响的同时也导致基因组内r DNA遗传结构的变化,显示纤毛虫原生生物可通过基因组高度的可塑性来快速适应抗生素胁迫.In order to understand the potential impact of antibiotic pollutants on marine protists, the marine ciliate Euplotes vannus was selected as a model organism to test the effects of oxytetracycline （OTC）, a tetracycline antibiotic widely used and distributed in coastal environments. The effects of OTC on growth, cell size, and small subunit ribosomal DNA （SSU rDNA） sequence polymorphisms were documented based on single-cell analysis. For the three OTC treatments used （concentrations of 1, 10, and 20 μg/mL）, the growth rate decreased significantly with increasing OTC concentrations, whereas cell size showed a tendency of increase, compared with the control. SSU rDNA of single cells generally exhibited lower haplotype and nucleotide diversity, along with slightly lower GC content at higher OTC concentrations. For single nucleotide polymorphisms in SSU rDNA sequences, the frequency of transition was much higher than that of transversion in both control and OTC treatments, although the frequency of transversion increased with increasing dose of OTC. In the treatment with the highest OTC dose, T to C transversion occurred more frequently and A to G reduced substantially, compared with the control. This study indicates that antibiotic pollution has a significant impact on phenotype and physiology of marine ciliates and can lead to changes in the genetic structure of genomic rDNA. It also highlights the high plasticity of protist genomes, which allows these unicellular eukaryotes to rapidly adapt to antibiotic stress.

关 键 词：扇形游仆虫 抗生素 污染物 种群生长 单细胞基因组分析 遗传多样性 

分 类 号：X503.22[环境科学与工程—环境工程] Q953[生物学—动物学]