丝氨酸蛋白酶抑制剂Serpin1对东亚飞蝗酶学免疫的影响

Effect of serine protease inhibitor Serpin1 on enzymatic immunity of Locusta migratoria manilensis

Serpins是东亚飞蝗Locusta migratoria manilensis体内具有免疫调节功能的一类丝氨酸蛋白酶抑制剂。前期研究发现Serpin1能够降低绿僵菌Metarhizium对蝗虫的杀虫效果,本研究旨在从酶学角度明确Serpin1蛋白抑制绿僵菌毒力的原因,进一步揭示Serpins的功能与作用机制。本实验采用饵剂饲喂的方法进一步明确Serpin1蛋白对绿僵菌侵染东亚飞蝗的抑制效果;测定绿僵菌侵染东亚飞蝗过程中,添加Serpin1蛋白对东亚飞蝗体内保护酶(超氧化物歧化酶SOD、过氧化物酶POD、酚氧化酶PO)、解毒酶(多功能氧化酶MFO、谷胱甘肽转移酶GSTs、乙酰胆碱酯酶AchE)共6种酶的影响,以明确Serpin1对东亚飞蝗酶学免疫的调节作用。结果表明,Serpin1能够显著降低绿僵菌对蝗虫的杀虫效果;将Serpin1与绿僵菌混合后处理东亚飞蝗,12 d后其死亡率为63.5%,显著低于绿僵菌单独处理(死亡率为80.6%)。酶活测定结果显示,将绿僵菌IMI330189与Serpin1蛋白混合处理后,与绿僵菌处理组相比,东亚飞蝗体内保护酶SOD和PO的活力总体表现为上调,而POD的活力呈现降低的趋势;解毒酶MFO、GSTs的活性呈现升高趋势,AChE的活力呈现先升高后降低的趋势。上述结果表明,Serpin1蛋白能够增强东亚飞蝗体内解毒酶和保护酶的活性,提高东亚飞蝗的酶学免疫,增强对绿僵菌侵染的抵御能力,从而降低东亚飞蝗的死亡率。本研究为进一步揭示Serpins的功能提供了参考。

Serpins are a class of serine protease inhibitors that perform immune function in Locusta migratoria manilensis.Previous studies had confirmed that the Serpin1 protein could effectively inhibit the infection of Metarhizium anisopliae on L.migratoria manilensis.This study aims to investigate the immune mechanism of Serpin1 in L.migratoria manilensis.The results showed that there was a significant difference in the cumulative mortality of L.migratoria manilensis among treatments.The cumulative mortality of M.anisopliae treatment was 80.6%,which was significantly higher than that of the control.And that of the M.anisopliae+Serpin1 treatment was 63.5%,which was significantly lower than that of M.anisopliae alone treatment.The results of enzyme activity assay showed that after mixing Serpin1 protein with M.anisopliae IMI330189,compared with the treatment of IMI330189 alone,the activity of protective enzymes SOD and PO increased,while that of POD decreased.Meanwhile the activity of detoxification enzymes MFO and GSTs generally increased with that of AChE showing a trend of increasing first and then decreasing.These results indicated that Serpin1 protein significantly improved the natural immune response of L.migratoria manilensis through increasing the activity of detoxification enzymes and protective enzyme,which enhanced the resistance of L.migratoria manilensis against M.anisopliae infection,thereby reduced the mortality of L.migratoria manilensis and provided evidence for revealing the function of Serpins.