PDF(Pubmed)
Abstract：
The larvae of some lampyrid beetles are highly specialized predators of snails. They have been observed to climb on the shells of their prey and use this exposed position to bite and inject secretions potentially originating from the midgut. Besides serving the purpose of extra-oral digestion (EOD), injected compounds also seem to have a paralyzing effect. Up to now, the toxins causing this paralyzing activity have not been identified. In the current study, we provide a first compositional analysis of the midgut secretion from lampyrid larvae, with a focus on identifying putative neurotoxins causing the observed paralyzing effect. For this purpose, we utilized a combined proteo-transcriptomic approach to characterize the compounds present in the midgut secretion of larval stages of Lampyris noctiluca. In terms of the absolute numbers of identified compounds, the midgut secretion is dominated by hydrolyzing enzymes comprising peptidases, carboxylesterases, and glycosidases. However, when considering expression levels, a few rather short cysteine-rich peptides exceed all other compounds. Some of these compounds show moderate similarity to putative neurotoxins identified in the venom of other arthropods and could be responsible for paralyzing effects. In addition to these potential toxins, we provide a list of peptides typical of the midgut secretion of L. noctiluca, supplemented by the corresponding precursor sequences.
摘要：
一些灯纹甲虫的幼虫是蜗牛的高度专业化捕食者。观察到它们爬上猎物的贝壳，并使用这种暴露的位置咬住并注入可能来自中肠的分泌物。除了用于口外消化（EOD）的目的，注射的化合物似乎也有麻痹作用。到目前为止,导致这种麻痹活动的毒素尚未确定。在目前的研究中,我们对Lumpyrid幼虫的中肠分泌进行了首次成分分析，重点是确定导致观察到的麻痹效应的假定神经毒素。为此,我们使用了一种组合的蛋白质转录组学方法来表征Lampyrisnoctiluca幼虫期中肠分泌中存在的化合物。就已鉴定化合物的绝对数量而言，中肠分泌由包含肽酶的水解酶主导，羧酸酯酶，和糖苷酶。然而,当考虑表达水平时，一些相当短的富含半胱氨酸的肽超过所有其他化合物。这些化合物中的一些与在其他节肢动物的毒液中鉴定出的推定的神经毒素显示出中等的相似性，并且可能是麻痹作用的原因。除了这些潜在的毒素,我们提供了夜光乳杆菌中肠分泌的典型肽列表，补充相应的前体序列。
