Cloning Genes Of GSTT1 And GSTM2 In Acartia Tonsa And Their Differential Expression In Response To 1,2-Dimethylnaphthalenestress

With the explosive growth of population and rapid development of modern industry,the demand of oil in society is increasing with years.Recently,the offshore drilling and oil spill accidents have occurred frequently,which caused serious marine oil pollution.Hence,the polycyclic aromatic hydrocarbons(PAHs),widely distributed in the marine environment,is choosen to be the target pollutant to investigate the expression level of GSTT1 and GSTM2 genes in Acartia tonsa exposed to different concentrations of PAHs.Besides,this paper also studied the toxic effects of Acartia tonsa under the stress of PAHs,which provided a scientific basis for biological monitoring and ecological risk assessment of PAHs in marine.PAHs is characterized by degradation-resistant,carcinogenic and biologic chain accumulation.PAHs can be adsorbed on marine sediments,suspended particles,macromolecule organics with high hydrophobicity,fat-soluble and octanol-water partition coefficient,and causes great harm to marine ecological environment through marine organisms accumulation and food chain.Copepods occupy an important position in marine ecological environment.They have small size,short life cycle and high sensitivity of marine pollutants.Due to the above characteristics,they are considered to be ideal marine environment monitors and environmental pollution indicators.Glutathione S-transferase(GST)is an enzyme that plays an important part in metabolism of PAHs.It catalyzes the combination of glutathione and intermediate metabolites,and makes it soluble compound to be excreted from body to achieve detoxification.In this experiment,Acartia tonsa in the laboratory incubator was considered to be the research object,and an acute toxicity experiment was carried out to determine medical lethal concentrations for 96h(96h-LC50).The result is the medical lethal concentrations for 96 h of PAHs 1,2-dimethylnaphthalene on Acartia tonsa was 114.171μg/L.At first,the complete coding sequence of Glutathione S-transferase GSTT1 and GSTM2 genes was obtained by gene sequence cloning.We used software to makegenes sequence multiple comparison and homology analysis,finding that GSTT1 and GSTM2 genes of Acartia tonsa had a high similarity with copecods.Then,quantitative real-time PCR was used to measure the expression changes of GSTT1 and GSTM2 genes of Acartia tonsa in different PAHs concentrations.Conclusions can be made that GSTM2 genes was more sensitive under PAHs stress,and GSTT1 was stronger than GSTM2 in the inhibition response mechanism.The regularity was contributed to explore the molecular mechanism of copepods under PAHs stress deeply.This paper aims to reveal a regularity about coping with PAHs pollution in complex environment,establish and improve the molecular biomarker index system for monitoring PAHs pollution in marine environment,and provide scientific data for marine ecological risk assessment.