VENOM COMPONENTS OF Asobara japonica IMPAIR CELLULAR IMMUNE RESPONSES OF HOST Drosophila melanogaster
VENOM COMPONENTS OF Asobara japonica IMPAIR CELLULAR IMMUNE RESPONSES OF HOST Drosophila melanogaster
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DOI：
10.1002/arch.21093
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发表时间：
2013-06-01
影响因子：
2.2
通讯作者：
Hayakawa, Yoichi
中科院分区：
文献类型：
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作者：
Furihata, Shunsuke X.;Matsumoto, Hitoshi;Hayakawa, Yoichi
内寄生蜂Asobara Japan onica具有剧毒：寄主果蝇幼虫被毒液杀死，毒液剂量是雌蜂在寄生时自然注射的剂量。然而，这种杀虫毒液是中和的，因为日本按蚊在产卵时注射毒液后不久就引入了侧输卵管成分。虽然这种寄生蜂的毒液和侧输卵管成分已经有了部分特征，但毒液成分如何促进黄蜂卵和幼虫在寄主中的成功发育仍然不清楚。在这里，我们证明了日本弧菌蛇毒不影响宿主体液免疫反应，但显著降低了宿主血细胞的两种细胞反应，即扩散和吞噬。此外，蛇毒成分在注射后4小时显著提高了丝氨酸蛋白酶样活性。侧方输卵管成分不能抵消毒液对宿主细胞免疫的不利影响，但显著降低了毒液诱导的蛋白酶活性的升高。毒液和侧输卵管成分中的活性因子都是分子量至少为10 kDa的热不稳定物质。寄主范围广的日本沼虾毒液的毒性远高于寄主范围有限的松材线虫毒液。这些结果表明，日本蜂毒毒性允许利用更广泛的寄主昆虫，因为它是克服寄主的细胞免疫反应才能成功寄生的关键。
The endoparasitoid wasp Asobara japonica has highly poisonous venom: the host Drosophila larvae are killed by envenomation at a dose that is naturally injected by the female wasp at parasitism. This insecticidal venom is neutralized, however, because A. japonica introduces lateral oviduct components soon after venom injection at oviposition. Although the venom and lateral oviduct components of this parasitoid have been partially characterized, how the venom components favor successful development of wasp eggs and larvae in the host remains ambiguous. Here, we demonstrated that A. japonica venom did not affect host humoral immune responses, determined as expression of antimicrobial peptide (AMP) genes, but significantly diminished two cellular responses, spreading and phagocytosis, by host hemocytes. Moreover, venom components drastically elevated a serine protease-like activity 4 h after its injection. The lateral oviduct components did not negate the detrimental effects of the venom on host cellular immunities, but significantly reduced the venom-induced elevation of protease activity. Both active factors in venom and lateral oviduct components were roughly characterized as heat-labile substances with a molecular mass of at least 10 kDa. Finally, venom of A. japonica, with a wide host range, was found to be much more toxic than that of Asobara rossica, which has a limited host range. These results reveal that A. japonica venom toxicity allows exploitation of a broader range of host insects because it is essential to overcome cellular immune responses of the host for successful parasitism.