Host/parasitoid interactions: critical timing of parasitoid-derived products.
Host/parasitoid interactions: critical timing of parasitoid-derived products.
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DOI：
10.1016/s0022-1910(98)00005-5
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发表时间：
1998-09
影响因子：
2.2
通讯作者：
J. J. Brown-J.;D. A. Reed
中科院分区：
文献类型：
--
作者：
J. J. Brown-J.;D. A. Reed
短期在体外孵育被用来检查endoparasitoid幼虫产生和释放蜕皮类固醇和蛋白质到他们的环境中的能力。用SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）观察到二龄龟和四齿Ascogasterquadridentata幼虫在20- 30 kD的分子量范围内释放时间相似的多肽。这些多肽的峰值发生正好与脱落的肛门囊泡，蜕皮前立即到第三龄。蜕皮也与体内从内寄生到外寄生发育的转变相一致。多克隆抗体的产生对一个特定的27 kD多肽的龟，这被认为是物种特异性和本地化主要在肛门囊泡在第二体育场的后期和第三龄的全身匀浆。体外掺入研究表明，在蜕皮前不久，二龄幼虫的合成能力迅速变化。蜕皮激素的产生和释放，通过RIA测定，被发现之前的峰值发生的27 kD多肽和蜕皮激素的存在是不可检测的蜕皮后。相反，观察到多肽在蜕皮前逐渐增加，在蜕皮后缓慢减少。在寄生蜂离开寄主后，才能在寄主组织中检测到Chelonus多肽。
Short-term in vitro incubations were used to examine the ability of endoparasitoid larvae to produce and release both ecdysteroids and proteins into their environment. Second instar larvae of both Chelonus near curvimaculatus and Ascogaster quadridentata were observed by SDS–PAGE to release temporally-similar polypeptides in the 20–30kD Mrrange. Peak occurrence of these polypeptides coincided with shedding of the anal vesicle, immediately prior to ecdysis to the third instar. Ecdysis also coincided with the switch from endoparasitic to ectoparasitic development in vivo. Polyclonal antibodies were generated against a particular 27kD polypeptide of Chelonus, which was found to be species-specific and localized primarily within the anal vesicle during the latter part of the second stadium and whole body homogenates of third instars. In vitro incorporation studies using35S-methionine indicated rapid changes in the synthetic abilities of second instar larvae shortly before ecdysis. The production and release of ecdysteroids, as measured by RIA, was found to precede the peak occurrence of the 27kD polypeptide and ecdysteroid presence was undetectable following the molt. In contrast, the polypeptides were observed to gradually increase prior to the molt and slowly decrease after the molt. The Chelonus polypeptide was not detected in host tissues until after parasitoid egression.