Institute for Molecular Bioscience, the University of Queensland, St. Lucia, Queensland 4072, Australia.
Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
Toxins (Basel). 2019 Nov 18;11(11):673. doi: 10.3390/toxins11110673.
Assassin bugs (Reduviidae) produce venoms that are insecticidal, and which induce pain in predators, but the composition and function of their individual venom components is poorly understood. We report findings on the venom system of the red-spotted assassin bug , a large species of African origin that is unique in propelling venom as a projectile weapon when threatened. We performed RNA sequencing experiments on venom glands (separate transcriptomes of the posterior main gland, PMG, and the anterior main gland, AMG), and proteomic experiments on venom that was either defensively propelled or collected from the proboscis in response to electrostimulation. We resolved a venom proteome comprising 166 polypeptides. Both defensively propelled venom and most venom samples collected in response to electrostimulation show a protein profile similar to the predicted secretory products of the PMG, with a smaller contribution from the AMG. Pooled venom samples induce calcium influx via membrane lysis when applied to mammalian neuronal cells, consistent with their ability to cause pain when propelled into the eyes or mucus membranes of potential predators. The same venom induces rapid paralysis and death when injected into fruit flies. These data suggest that the cytolytic, insecticidal venom used by reduviids to capture prey is also a highly effective defensive weapon when propelled at predators.
猎蝽（Reduviidae）产生的毒液具有杀虫作用，并能引起捕食者疼痛，但它们个体毒液成分的组成和功能仍知之甚少。我们报告了关于红斑猎蝽毒液系统的发现，红斑猎蝽是一种起源于非洲的大型物种，当受到威胁时，它会将毒液作为投射武器来喷射。我们对毒液腺（后主腺 PMG 和前主腺 AMG 的单独转录组）进行了 RNA 测序实验，并对防御性喷射的毒液或通过电刺激从喙中收集的毒液进行了蛋白质组实验。我们解析了一个包含 166 种多肽的毒液蛋白质组。防御性喷射的毒液和大多数对电刺激做出反应而收集的毒液样本显示出与 PMG 预测分泌产物相似的蛋白质谱，而 AMG 的贡献较小。当应用于哺乳动物神经元细胞时，混合毒液样本通过膜裂解诱导钙离子内流，这与它们在喷射到潜在捕食者的眼睛或黏液膜时引起疼痛的能力一致。同样的毒液注射到果蝇体内会导致其迅速瘫痪和死亡。这些数据表明，猎蝽用于捕捉猎物的细胞毒性、杀虫毒液也是一种在喷射到捕食者时非常有效的防御性武器。
