磺胺类抗生素对斜生栅藻的协同和拮抗作用研究

Synergism and Antagonism Effects of Sulfonamide Antibiotics to Scenedesmus obliquus

环境中抗生素复合污染产生的毒性效应具有潜在风险。为系统考察磺胺类抗生素(SAs)混合物的联合毒性效应,以环境中常见的磺胺吡啶(SPY)、磺胺甲基嘧啶(SMR)、磺胺二甲嘧啶(SM2)、磺胺甲氧哒嗪(SMP)、磺胺甲恶唑(SMZ)和磺胺喹噁啉(SQ)6种SAs及其二元混合物体系(共75条混合物射线)为研究对象,利用96孔微板测定6种SAs及其二元混合物对斜生栅藻(So)的生长抑制毒性,通过浓度加和(CA)、独立作用(IA)模型和模型偏移率(MDR)分析混合物的联合毒性及毒性相互作用。结果表明,6种SAs及其混合物射线对So在96 h呈现明显的毒性,但不同SAs的毒性大小不同,以半数效应浓度的负对数(pEC_(50))为毒性大小指标,6种SAs的毒性大小顺序为:SQ(pEC_(50)=5.311)>SPY(pEC_(50)=3.757)≈SMZ(pEC_(50)=3.749)>SMP(pEC_(50)=3.680)>SM2(pEC_(50)=3.090)>SMR(pEC_(50)=2.595);不同组分SAs混合物对So的联合毒性存在差异,大部分混合物毒性存在组分浓度依赖性,而有小部分混合物毒性则不存在组分浓度依赖性;15个SAs混合物体系以拮抗作用和协同作用为主。混合体系组分的浓度比不同会产生不同的相互作用类型。在10%效应下,含有组分SPY的混合体系大多呈现协同作用,且随组分SPY浓度比的增大,协同作用增强。含有组分SMR的混合体系均呈现拮抗作用,且随着组分SMR浓度比的增大,拮抗作用增强。研究成果为抗生素的生态风险评估提供重要的基础数据。

The toxic effects of combined pollution of antibiotics in the environment may pose potential risks.In order to investigate the combined toxic effects of sulfonamide antibiotics(SAs)mixture,six SAs in the environment(sulfapyridine(SPY),sulfamerazine(SMR),sulfamethazine(SM2),sulfamethoxypyridazine(SMP),sulfamethoxazole(SMZ),sulfaquinoxaline(SQ))and their binary mixture system(included 75 mixture rays)were selected and their growth inhibition toxicities to Scenedesmus obliquus(So)were determined by using the 96-well microplate.Concentration addition(CA),independent action(IA)and model deviation ratio(MDR)were applied to analyze the combined effects and toxicity interactions.The results showed that the toxicities of the six SAs and their mixture rays presented obvious toxicities to So after 96 h expose.The negative logarithm of the median effect concentration(pEC_(50))was used as a toxicity index.The toxicity order of six SAs followed:SQ(pEC_(50)=5.311)>SPY(pEC_(50)=3.757)≈SMZ(pEC_(50)=3.749)>SMP(pEC_(50)=3.680)>SM2(pEC_(50)=3.090)>SMR(pEC_(50)=2.595).The difference in the combined toxicities to So was observed for the SAs mixtures composed of different components.Most of the mixture toxicities depended on the component concentration,while a small part of them did not depend on the component concentration.The antagonistic and synergistic effects were dominant in the 15 SAs mixture systems.The mixture systems containing SPY mainly showed a synergy at 10%effect and the toxic interaction increased with the increasing concentration ratio of SPY.The mixture systems containing SMR mainly showed an antagonistic effect,and the antagonism was enhanced with the increasing SMR concentration ratio.The results will provide important basic data for the ecological risk assessment of antibiotics.