This study investigated the cytotoxicity of gemcitabine using the marine ciliate Euplotes vannus as the test organism.The median lethal concentrations(LC50 values)were determined using acute toxicity tests within an e...This study investigated the cytotoxicity of gemcitabine using the marine ciliate Euplotes vannus as the test organism.The median lethal concentrations(LC50 values)were determined using acute toxicity tests within an exposure time of 30 min with 0,6,12,24,and 48 mg mL^-1 gemcitabine.The median inhibition effect(IC50 value)on the growth of the ciliate cells was examined using chronic toxicity tests within 5 days(120 h)after exposure for 30 min with 0,0.7,3.5,7,and 14 mg mL^-1 gemcitabine.The 30-min LC50value was 10.66-mg mL 1.The LC50 values decreased with increasing exposure times and well fitted to the toxicity curve equation LC50=10.93+28.4e^-0.19t(R2=0.93;P<0.05,t=exposure time).The IC50 value for growth rates was 7.05 mg mL^-1,and the inhibition effect on growth rates well fitted to the model equation r%=0.8681e^-0.0782Cgem(r%means growth rate with inhibition by gemcitabine,Cgem means concentrations of gemcitabine,R^2=0.99 and P<0.05).The LC50 values of a wide range of gemcitabine concentrations could therefore be predicted for any given exposure time.These results suggest that the clinical dose of gemcitabine(20 mg mL^-1)was higher than the 30-min LC50 value,which was almost the same as the 6-min LC50 value(19.88 mg mL^-1)for E.vannus cells.The results also demonstrate that E.vannus can be used as a robust test organism for bioassays of chemotherapeutic drugs during short exposure periods.展开更多
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(...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.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 31672308 and 40206021)
文摘This study investigated the cytotoxicity of gemcitabine using the marine ciliate Euplotes vannus as the test organism.The median lethal concentrations(LC50 values)were determined using acute toxicity tests within an exposure time of 30 min with 0,6,12,24,and 48 mg mL^-1 gemcitabine.The median inhibition effect(IC50 value)on the growth of the ciliate cells was examined using chronic toxicity tests within 5 days(120 h)after exposure for 30 min with 0,0.7,3.5,7,and 14 mg mL^-1 gemcitabine.The 30-min LC50value was 10.66-mg mL 1.The LC50 values decreased with increasing exposure times and well fitted to the toxicity curve equation LC50=10.93+28.4e^-0.19t(R2=0.93;P<0.05,t=exposure time).The IC50 value for growth rates was 7.05 mg mL^-1,and the inhibition effect on growth rates well fitted to the model equation r%=0.8681e^-0.0782Cgem(r%means growth rate with inhibition by gemcitabine,Cgem means concentrations of gemcitabine,R^2=0.99 and P<0.05).The LC50 values of a wide range of gemcitabine concentrations could therefore be predicted for any given exposure time.These results suggest that the clinical dose of gemcitabine(20 mg mL^-1)was higher than the 30-min LC50 value,which was almost the same as the 6-min LC50 value(19.88 mg mL^-1)for E.vannus cells.The results also demonstrate that E.vannus can be used as a robust test organism for bioassays of chemotherapeutic drugs during short exposure periods.
文摘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.
