放线菌酮对小球藻的毒性效应及其机制研究

The research of toxic effects and mechanisms of cycloheximide on Chlorella sp.

为探究抗生素对藻类的毒性效应与机制,以放线菌酮(cycloheximide,CHX)为潜在污染物,以小球藻为受胁迫对象,通过检测小球藻细胞密度、叶绿素a(chlorophyll a)、活性氧(reactive oxygen species,ROS)、丙二醛(malondialdehyde,MDA)和PSⅡ最大光化学量子产量(optimal/maximal quantum yield of PSⅡ,F_(v)/F_(m))等生长及生理生化指标,探究抗生素对藻类的毒性效应.研究结果表明CHX对于小球藻的96 h EC_(50)为1.229 mg/L.在该质量浓度下作用96 h后,CHX对小球藻细胞密度的抑制率为49.7%,使叶绿素a的含量降低了36.2%,对F_(v)/F_(m)的抑制率为13.0%.此外,与对照相比,CHX暴露使小球藻的ROS和MDA分别上升了533.7%和618.6%.因此,CHX对小球藻的毒性效应主要体现为生长抑制,其可能的机制是引起氧化应激(如产生ROS和MDA),进而抑制细胞的光合作用(降低F_(v)/F_(m)).

To explore the toxic effect and mechanism of antibiotics on algae.cycloheximide(CHX)as a potential contaminant was used on Chlorella sp..The amount of biomass,chlorophyll a,reactive oxygen species(ROS),malondialdehyde(MDA)and Optimal/maximal quantum yield of PSⅡ(F_(v)/F_(m))were chosen as biochemical and physiological parameters.The results of the study showed that the EC_(50) of 96 h is 1.229 mg/L for Chlorella sp.under CHX.After 96 h of exposure to this concentration,the inhibition rate of CHX on algal biomass was 49.7%,the inhibition rate of CHX on chlorophyll a was 36.2%and the inhibition rate of CHX on F_(v)/F_(m)was 13.0%.In addition,the CHX could stimulate the production of ROS and MDA of Chlorella sp.:the promotion rate of ROS and MDA were 533.7%and 618.6%respectively.Therefore,the toxic effect of CHX on Chlorella sp.mainly acts on growth inhibition,its possible mechanism is to cause oxidative stress(such as the production of ROS and MDA),furthermore,it inhibits photosynthesis(reduces F_(v)/F_(m)).