低盐胁迫对光裸方格星虫相关组织结构和非特异性免疫酶的影响

Effects of low salinity pressure on biological tissue and immunity enzymes activities of Sipunculus nudus

为了解光裸方格星虫(Sipunculus nudus)在低盐环境下的生物和生理响应,文章在盐度分别骤降0 (S30)、5(S25)、10 (S20)、15 (S15)、20 (S10)、25 (S5)的水体中养殖方格星虫96 h,比较研究盐度骤降对光裸方格星虫相关组织结构和非特异性免疫酶的影响。结果显示:1)方格星虫可以耐受盐度骤降10,骤降超过15时则会明显死亡。2)低盐胁迫造成方格星虫体腔液显著增加(P<0.05),体腔液体积与方格星虫体质量相关性较高(R^(2)>0.96)。3)体腔液渗透压和肌肉蛋白质含量均随着盐度的下降而显著降低(P<0.05)。4)低盐胁迫造成纵肌纤维和环肌纤维变细、柱状上皮细胞染色变浅,引起触手上皮细胞体积增大,黏附能力降低。5) S25、S30处理组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性相对稳定,S10、S15组体腔液SOD活性和体壁肌肉CAT活性先降低后升高,而S10、S15组体腔液CAT活性先升高再降低。方格星虫体腔液SOD和CAT活性变化规律较体壁肌肉明显。综上,在盐度骤降超过15时,将严重影响方格星虫的成活率和渗透压,造成体壁和触手结构变化,导致体内免疫酶活变化甚至失活,影响正常代谢活动。

In order to understand the response of the biological and physiological indicators of Sipunculus nudus to low salinity,we evaluated the effects of low salinity pressure on the survival rate,osmotic pressure,biological tissue and immunity enzymes activities of S.nudus which were cultured for 96 h in water with abrupt salinity drop of 0(S30),5(S25),10(S20),15(S15),20(S10)and 25(S5).The results show that:1)S.nudus could tolerate the salinity drop of 10,but would die when the salinity dropped over 15.2)The coelomic fluid of S.nudus increased with the decrease of water salinity significantly,and there was a significant positive correlation between the body mass and coelomic fluid volumn(R^(2)>0.96).3)The osmotic pressure and body protein contents decreased with the decrease of water salinity(P<0.05).4)In the low salinity treatments,the connective tissue of longitudinal and circumferential muscle fibers of the body wall were thin,and the staining of columnar cells was lighter.For the tentacle,its adhesion ability was weaker as the epithelial cells became larger.5)SOD and CAT activities in the groups of S30 and S25 were relatively stable,while the body SOD and coelomic fluid CAT in the groups of S10 and S15 first decreased and then increased;however,the CAT of coelomic fluid in the groups of S10 and S15 first increased and then decreased.SOD and CAT activities in the coelomic fluid had strong vara-tion.In summary,low salinity pressure can affect the survival rate,osmotic pressure,biological tissue and immunity enzymes activit-ies of S.nudus significantly.