| Petroleum contains benzene-series compounds(e.g.phenanthrene,anthracene,pyrene,phenols and other toxic organics)is very destructive to ocean ecosystem,which effects on ocean creatures physically and chemically.Shellfish with poor mobility are vulnerable to the long-term impact of oil pollution,resulting in the accumulation of petroleum hydrocarbons,harms to shellfish and then entering the human body through the food chain.The thesis measured the natural water petroleum hydrocarbon distribution in the body through the hydrostatic simulation experiments with whole water change,puts Scapharca subcrenata in water-soluble fraction of crude oil(WSF),to analyze its absorption and release rule of petroleum hydrocarbons,the change characteristics of the antioxidant,metabolism and malondialdehyde index,0 h,24 h,72 h is selected to the transcriptome,in order to reveal the distribution rule of petroleum hydrocarbons in the Scapharca subcrenata,discuss its effect on biochemical indicators of an individual,and the response process of petroleum pollution,study its response mechanism,which can provide some reference for the healthy ecological cultivation of shellfish resources.The main research results are as follows:1.The rule of oil hydrocarbon absorption and release of the Scapharca subcrenata.By contact with infected method,Scapharca subcrenata exposure concentration were 0.1,0.2,0.4,0.8,1.6,3.2 mg/L WSF,to explore the rule of petroleum hydrocarbon of Scapharca subcrenata release,the results show that concentration after 10 d,petroleum hydrocarbon content in the Scapharca subcrenata were 9.3,62.0,88.2,122.4,144.2,156.7,176.4 mg/kg,absorption rate change with WSF concentration is y = 14.37 + 3.924 log x(r2 = 0.9766);Released after 10 d,petroleum hydrocarbon content in the Scapharca subcrenata were 11.1,13.4,13.9,14.2,15.5,17.3 mg/kg,relation between release rate and WSF content in enrichment stage was y = 12.86 + 3.139 log x(r2 = 0.9734);Biological enrichment coefficients were 619.7,441.2,305.9,180.2,97.9,55.1,and the relation with WSF content was y = 14.37 + 3.294 log x(r2 = 0.9861)2.Distribution of petroleum hydrocarbon in the Scapharca subcrenataThe petroleum hydrocarbon content of the Scapharca subcrenata was found: 187mg/kg of group 2(Scapharca subcrenata ages below 2 years),the content of each tissue was 77.46 mg/kg in the axe foot,362.60 mg/kg in the viscera mass,256.66 mg/kg in the gill tissue,62.14 mg/kg in the adductor muscle and 62.57 mg/kg in the mantle.In group 1(Scapharca subcrenata ages beyond 2 years),115mg/kg of Scapharca subcrenata,85.14mg/kg of axe foot,320.51mg/kg of visceral mass,195.08mg/kg of gill tissue,47.12mg/kg of adductor muscle,79.86mg/kg of the mantle.The group 1 content of petroleum hydrocarbon in the tissues was higher than group 2,and the content of visceral mass,gill tissue and adductor muscle was higher than other tissues.The content of petroleum hydrocarbon was lower in group 1,but the content of petroleum hydrocarbon was higher in axe foot and mantle.Group 2 are more vulnerable to petroleum hydrocarbons.3.Effects of crude oil on partial antioxidant enzymes and metabolic enzymes of Scapharca subcrenataTo measure the activities of antioxidant enzymes—includes superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GPX)—and metabolic enzymes —includes acid phosphatase(ACP),alkaline phosphatase(AKP),Na+/K+ ATPase,Ca2+/Mg2+ ATPase—in gill and muscle tissues of local bivalve,Tianjin population of Scapharca subcrenata was used.Lipid oxidant degree(content of malondialdehyde,MDA)was also measured.Exposure test set at four concentrations(0.01mg/L,0.1mg/L,1mg/L,3mg/L)of water soluble fraction of Dagang crude oil(WSF).Integrated biomarker response(IBR)is used.Results showed that activities of SOD,CAT and GPX under influence of WSF appeared a dose-effect relationship.MDA increased first and decreased later.In both tissues,MDA accumulated in 3mg/L group.ACP,AKP,and Ca2+/Mg2+ ATPase activities showed a light dose-effect relationship.ACP responded more rapidly than AKP.Na+/K+ ATPase was more vulnerable than Ca2+/Mg2+ ATPase.During expose,WSF influenced gill tissuses more obviously than muscle tissues.As a result,gill appeared higher activities of SOD,GPX and MDA than axe foot,while CAT was contrary.RIB values of muscle and gill tissues decreased first and then increased.There were dose-effect and time-effect relationships with WSF concentration and exposure time.There were differences between the two groups.The cumulative RIB values of muscle tissues were higher than that of gill tissues.4.Transcriptome analysis of Scapharca subcrenata under WSF stressThe transcriptome analysis of the response of petroleum hydrocarbon WSF stress in the Scapharca subcrenata provides a reference for the exploration and utilization of petroleum hydrocarbon tolerance and related genes in the Scapharca subcrenata.Transcriptome sequencing technology was used to conduct high-throughput transcriptome sequencing based on RNA-seq in Scapharca subcrenata under 3mg/L WSF stress at 0h,24 h and 72 h.The unigenes were assembled and annotated,and antioxidant-and metabolization-related genes were screened for verification.Eight unigenes were selected: Cytochrome P450 26A1(C3563306),Cytochrome P450 10(scaffold104991),carbonyl reductase [NADPH] 3(scaffold31876),Titin(scaffold41173),arginine kinase(C3555194),L-ascorbate acid oxidase(C3565206),spermine oxidase(C3565206),inositol 3-phosphate synthase 1-B(scaffold99611). |
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