脂多糖诱导的水椰八角铁甲免疫响应动态及其在性别间的差异

Lipopolysaccharide-induced immune response of Octodonta nipae( Coleoptera: Chrysomelidae) adults in relation to their genders

【目的】研究昆虫免疫诱导后的响应模式是揭示昆虫免疫适应性变异、免疫权衡和免疫致敏现象的关键。本研究旨在探讨水椰八角铁甲Octodonta nipae(Maulik)免疫诱导的动态响应变化及其在性别间的差异。【方法】将革兰氏阴性细菌细胞壁提取物脂多糖(LPS)注射到水椰八角铁甲雌雄成虫体腔内,诱导其免疫系统响应,测定了两个重要免疫参数酚氧化酶(phenoloxidase,PO)活性和抗菌肽(antimicrobial peptide,AMP)抑菌活性在免疫诱导前后的动态变化。【结果】LPS(2.5 mg/m L×138 n L)诱导可以使水椰八角铁甲PO活性和AMPs的抑菌活性在一定时间范围内(雌虫PO活性和AMPs抑菌活性分别在诱导后4-10 h和12-48 h,雄虫PO活性和AMPs抑菌活性分别在诱导后0.1-10 h和4-48 h)显著高于空白对照;AMPs抑菌活性的提升时间迟于PO活性。但持续时间长于PO活性。免疫诱导前,成虫的PO活性和AMPs抑菌活性均是雌性显著高于雄虫;同样在免疫诱导后,成虫PO活性和AMPs抑菌活性的最高水平也是雌性显著大于雄虫,但活性提升的时间是雄性早于雌虫。【结论】LPS能够显著诱导水椰八角铁甲雌雄成虫的免疫响应,而且雌成虫的免疫响应明显高于雄性。通过对水椰八角铁甲免疫物质动态变化的认识,为水椰八角铁甲入侵到新生境后免疫相关适应性变异及安全有效的生物防治方法的研究奠定了基础。

【Aim】Understanding the response patterns of insects after immunity induction is a basis to reveal the mechanisms of adaptive immune response,immune trade-offs and immune priming. The study aims to clarify the dynamic changes of the immune response in Octodonta nipae( Maulik) adults induced by bacteria and the response differences between males and females. 【Methods】The cell-wall extract lipopolysaccharide( LPS) of gram negative bacteria was injected into the body cavity of O. nipae adults to induce their immune response. The activities of phenoloxidase( PO) and antimicrobial peptide( AMPs),which play an important role in insect innate immunity,were assayed at different time post induction.【Results】The PO activity and the antibacterial activity of AMPs in O. nipae adults were significantly induced by 2. 5 mg / m L × 138 n L LPS in a certain time period,and the response models were different between females and males. The PO activities in LPS-induced female( 4- 10 h post induction) and male adults( 0. 1- 10 h post induction),as well as the antibacterial activity of AMPs in LPS-induced female( 12- 48 h post induction) and male adults( 4- 48 h post induction),were significant higher than those of the blank control,respectively. LPS induced a faster increase of PO activity than of AMPs activity,but the increase of AMPs activity lasted for a longer time. Before immune induction,the PO activity and the antibacterial activity of AMPs in female adults were significant higher than those in male adults; and after immune induction the PO activity and the antibacterial activity of AMPs in female adults also had a highertop level. 【Conclusion】The results suggest that LPS can induce a dynamic immune response in O. nipae adults,which is different between males and females. Our findings provide a foundation for further studies on adaptive immune response of O. nipae in the new invading environment and to develop an effective strategy to control O. nipae.