低盐胁迫对华贵栉孔扇贝抗氧化酶、Na^+/K^+-ATPase活力的影响

Effects of Low-salinity Stress on Antioxidant Enzymes and Na^+/K^+-ATPase Activities of Mimachlamys nobilis

采用生物化学方法系统测定了低盐(18)胁迫下华贵栉孔扇贝(Mimachlamys nobilis)3种组织(肝脏、鳃、外套膜)的3种抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT、髓过氧化物酶MPO)活力、丙二醛MDA含量、Na^+/K^+-ATPase活力和肝脏糖原含量在3,6,9,12,24,48,72,96 h的动态变化,可为揭示华贵栉孔扇贝不同组织在低盐胁迫下的应激反应规律和免疫防御调节机制提供科学依据.结果表明:3种组织在低盐胁迫下的各种生理应答基本一致;3种抗氧化酶(SOD、CAT、MPO)活力随着胁迫时间的延长,呈现先增大后减小的趋势,一般在胁迫9或12 h到达最高值,随之降低逐渐恢复与起始时没有显著差异;MDA含量随胁迫时间延长持续上升;Na^+/K^+-ATPase活力随胁迫时间延长持续下降;肝脏糖原含量随胁迫时间延长持续下降.说明盐度下降后机体抗氧化系统受损,体内离子平衡被打破,能量供应不足,是导致华贵栉孔扇贝死亡的重要原因.因此在福建沿海选择其养殖区域应避免在洪水和台风季节盐度降至18的海区.

Under low-salinity （18） stress on Mimachlamys nobilis, activities of superoxide dismutase （ SOD）, catalase （ CAT）, myeloperoxidase （ MPO）, content of MDA, Na ＋/K ＋ -AT- Pase activity in three tissues （liver, gill, mantle） and glycogen content in liver were analyzed and compared at 0, 3 , 6 , 9 , 12 , 24 , 48, 72 , 96 h by their corresponding biochemical meth- ods. The results showed that physiological responses of three tissues were similar under low-salinity stress. Activities of three antioxidant enzymes （ SOD, CAT, MPO） increased with extension of du- rature, reached their peak after 9 h or 12 h respectively, and then decreased. MDA content in- creased with duration, MDA content after 12 to 24 h compared to the initial level （0 h） had signifi- cant difference （P 〈 0. 05 ） . Activity of Na ~/K ~ -ATPase decreased with time elapse, activity af- ter 3 to 12 h compared to the initial level had significant difference （P 〈 0. 05 ） . Glycogen content in liver decreased with time elapse, glycogen content after 6 h compared to the initial level had sig- nificant difference （P 〈 0. 05）. In conclusion, low-salinity stress would damage the antioxidant sys- tem, break the ion balance, have the insufficient energy supply, which were the important reasons leading to death of M. nobilis. The farming sites in Fujian coast should be avoided areas where the salinity falls to 18 in the flood and typhoon season.