Effects of B(a)P on immunomodulation,biochemical responses and DNA damage in the marine gastropod abalone Haliotis diversicolor.pdf

1、It has been reported that organic xenobiotics commonly found as pollutants in themarine environment impair immune capabilities of marine organisms.The purpose of thepresent study was to investigate the effects of benzo(a

2、)pyrene [B(a)P] onimmunomodulation, oxidative stress and antioxidant defences in marine gastropods.Inthe first part of present study, the marine gastropod abalone Haliotis diversicolor wasexposed to sublethal concentrati

3、ons of B(a)P for shorter exposure periods and second partabalone exposed to environmentally realistic concentrations of B(a)P for longer exposureperiods.During the study, alterations of hematological parameters like haem

4、ocyte count,haemocyte viability, protein content and immune components like phenoloxidase,phagocytosis and superoxide anion generation were measured.In addition, the changes inlysozyme activity, antibacterial activity du

5、e to the effect of B(a)P on abalone wereanalysed.B(a)P was found to decrease significantly the total number of circulatinghaemocytes.Intracellular superoxide anion generation and phenoloxidase significantlyincreased on e

6、xposure to B(a)P, whereas phagocytic activity was decreased significantlyat higher concentration.Significant alterations were found in the uptake of neutral redand results of the present study showed that alteration in t

7、he immune function in abalonemay be due to the generation of reactive oxygen species produced by the animal due toeffect of B(a)P.The results are discussed in the light of elucidating the possiblerelationship between env

8、ironmental contaminants and the immunological parametersstudied.
　　During the study, sublethal effect of B(a)P on oxidative stress and modulation ofantioxidant defenses were evaluated in different tissues of a H.diver

9、sicolor.Levels oflipid peroxides (LOOH), thiobarbituric-acid reactive substances (TBARS), proteincarbonyls (CP) and low-(L-SH) and high-molecular weight thiols (H-SH) were measuredfor oxidative stress.CP, LOOH and TBARS

10、contents increased significantly in gill,kidney and hepatopancreas after B(a)P exposure.L-SH concentrations increased up to 2fold in gill, kidney and muscle.The modulation of a suite of antioxidant defence enzymesincludi

11、ng superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST),glutathione peroxidase (GPx), glutathione (GSH) in different tissues of abalone exposedto nominal concentrations of B(a)P for 7 d were observ

12、ed.The activities of SOD andCAT were altered under B(a)P exposure.In most tissues, the activities of glutathione-utilizing enzymes (GPx, GST, GSH) were affected under B(a)P exposure.The GSH leveldecreased nearly 67 and 7

13、4 ％ in gonad and hepatopancreas whereas the same decreasedapproximately 40％ in gill, kidney and mantle.B(a)P at 0.08 mg l-1 increased the level ofGST in gill and kidney by 85％ and 125％, respectively, whereas the same inc

14、reased to62％ in hepatopancreas.Correlation analysis showing a relationship between oxidativestress and antioxidant defenses in abalone exposed to B(a)P was significant.However,during the long term exposure to environment

15、ally realistic concentration of B(a)P, theantioxidant parameter showed no significant changes except in some tissues after 14 daysexposure.Conversely, DNA damage increased in all the tissues after 28 d exposure.Overall t

16、he results indicate that the gill, kidney and hepatopancreas were the mostsensitive organs to oxidative damage and thus suggest that H.diversicolor could be usedas a suitable bioindicator of exposure to organic pollutant

17、 measuring activities ofantioxidant enzymes.
　　In addition, the objective of this study was to investigate the sublethal effects of B(a)P on marker enzymes (EROD; LPO; AChE, phosphatases and transaminases indigestive

18、gland, gill, gonad and hemolymph in the edible gastropod abalone H.diversicolor.Significant differences between control and B(a)P exposed abalone were observed for biomarkers enzymes studied.The four marker enzyme (ACP,

19、ALP, ALTand AST) exhibited a similar pattern in all the tissue studied, while EROD and LPOshowed induction in all tissues and AChE showed decreasing trends.In contrast, thehemolymph showed increasing in activities of mar

20、ker enzymes except for AChE.Theactivity of ACP and ALP decreased nearly 33 and 24 ％ in digestive gland similarlyALT and AST activity decreased up to 25 and 69 ％ in digestive gland when the abalonewere exposed to B(a)P at

21、 0.08 mg 1-1.All the results were tested statistically andinterpreted accordingly and the results indicate that the measurement of biomarkerresponses is technically feasible.The performance of each biomarker is assessed