摘要:
以3种氨基糖苷类(AG)抗生素:硫酸安普霉素(APR)、双氢链霉素(DIH)和硫酸链霉素(STS)为研究对象,以生态系统中2类重要的水生生物分解者如青海弧菌(Vibrio qinghaiensis sp.-Q67, Q67)和生产者蛋白核小球藻(Chlorella pyrenoidosa, CP)为受试生物,运用均匀设计射线法设计抗生素三元混合物体系,共5条具有不同浓度配比的射线,应用已建立的分别基于Q67和CP的时间毒性微板分析法系统测试抗生素及其三元混合物射线对Q67和CP在不同暴露时间的毒性。对于Q67和CP,暴露时间分别为0.25、2、4、8、12 h和12、24、48、72、96 h。应用浓度加和(CA)模型分析混合物在不同暴露时间的毒性相互作用。结果表明:APR、DIH和STS及其5条混合物射线对2种指示生物的毒性均具有明显的时间依赖性,且Q67对AG抗生素及其混合物射线的响应比CP的灵敏;以半数效应浓度的负对数pEC50值为毒性大小指标,3种抗生素对2种指示生物的毒性大小顺序随暴露时间的变化而变化,3种AG抗生素对Q67和CP分别在12 h和96 h的毒性大小顺序均为STS > DIH > APR;5条具有不同浓度配比的混合物射线对Q67在不同暴露时间的毒性均呈加和作用,但对CP的毒性既有加和作用也有拮抗作用,且拮抗作用随暴露时间和组分浓度配比的变化而变化,表明AG抗生素毒性的联合毒性作用与暴露生物、暴露时间以及混合物组分的浓度配比等有关。
Abstract:
Three aminoglycosides (AG) antibiotics, apramycin sulfate (APR), dihydrostreptomycin (DIH) and streptomycin sulfate (STS), were selected as the research objects, and the decomposer and producer in the aquatic ecosystem such as freshwater photobacteria Vibrio qinghaiensis sp.- Q67 (Q67) and green algae Chlorella pyrenoidosa (CP) were taken as the test organisms. The toxicity data of the three AG antibiotics and their ternary mixture rays designed by uniform design ray (UD-Ray) method at different exposure time were determined by using the established time-dependent microplate toxicity analysis (t-MTA) based on Q67 and CP, respectively. The exposure time points were 0.25, 2, 4, 8 and 12 h for Q67 and 12, 24, 48, 72 and 96 h for CP. The toxicity interaction within mixture rays was analyzed by the additive reference model, namely concentration addition (CA). The main results showed that the toxicity of three AG antibiotics and their mixture rays towards both organisms Q67 and CP displayed time-dependency and Q67 was more sensitive than CP. For the two test organisms, the toxicity order of the three antibiotics at different time varied based on the negative logarithm of median effect concentration (pEC50). Toxicity order of the three AG antibiotics at the exposure time of 12 h for Q67 and 96 h for CP were both followed by: STS > DIH > APR. The toxicity of all the ternary mixture rays with different concentration ratios towards Q67 at different exposure time exhibited classical additive action. But the toxicity of five ternary mixture rays towards CP exhibited both additive action and antagonism and the antagionism was of concentration ratio-dependency and time-dependency. All the results indicated toxicity interaction of three AG antibiotics correlated well with exposure organisms, exposure time and concentration ratios.