中华双环粒蟹奴寄生对红星梭子蟹蜕皮相关激素和基因表达量

Effect of the Parasitism of Diplothylacus sinensis on the Ecdysteroid Hormone Content and Molting Related Gene Expression from the Three-spot Swimming Crab Portunus sanguinolentus

[目的]研究中华双环粒蟹奴寄生对不同蜕皮阶段红星梭子蟹蜕皮激素含量、MIH基因和EcR基因相对表达量的影响,为深入探究该类甲壳动物寄生虫的寄生机理提供基础资料。[方法]采集200尾健康和受蟹奴寄生的红星梭子蟹为试验材料进行室内饲养,观测和记录试验蟹蜕皮间期所需时间,并分别于4个不同的蜕皮阶段抽取血淋巴样品,开展蜕皮激素和相关基因表达量检测。[结果]雄性和雌性感染蟹蜕皮间期耗时均大于健康蟹,分别为(291.5±115.5)h和(342.1±144.5)h;感染蟹蜕皮间期和前期血淋巴EH含量显著低于正常蟹同期水平(P<0.05);各期感染蟹MIH基因相对表达量均高于正常蟹,而EcR基因相对表达量则呈相反趋势;血淋巴EH含量与EcR基因相对表达量呈正相关关系,与MIH基因相对表达量呈负相关关系。[结论]中华双环粒蟹奴通过干扰红星梭子蟹蜕皮激素合成和相关基因表达以抑制其正常蜕皮,主要作用时期为蜕皮间期和蜕皮前期。

[Objective]In order to provide basic data for the parasitic mechanism of rhizocephalan parasites on their crustacean hosts,this paper studied the parasitical effect of Diplothylacus sinensis on the content of ecdysteroid hormone(EH)and the expression of MIH and EcR gene from different molting stages of Portunus sanguinolentus.[Method]Two hundred three-spot swimming crabs,including 100 healthy individuals and 100 infected individuals were collected and cultured in experimental ponds equipped with a circular flow system.The duration of intermolt period of crabs was recorded.The haemolymph of crab in different molting stages was drawn off from the third pereiopod with syringes,and then the EH content and the MIH and EcR gene expression were examined.[Result]The duration of intermolt period for male and female infected crabs was(291.5±115.5)h and(342.1±144.5)h,respectively,both of which were longer than healthy crabs.The EH contents of infected crabs in intermolt and premolt period were significantly(P<0.05)lower than those of normal crabs.In all of the four molting stages,the relative gene expressions of MIH in parasitized crabs were higher than those in healthy crabs,while the EcR gene expression showed the opposite trend.In total,the variation of EH content exhibited positive relationship with the EcR gene expression,but showed negative relationship with the MIH gene expression.[Conclusion]The parasitism of D.sinensis mainly affects the host’s molting through interfering with the synthesis of ecdysteroid hormone and the gene expression of MIH and EcR during the intermolt and premolt period.