Action and Composition of Assassin Bug Venom

IBN-9727532 PI：EDWARDS 一些动物可以产生毒液，其中不仅包含缓慢作用的酶，还包含非常快速作用的神经毒素，这些神经毒素是对神经细胞的信号或传输特性产生巨大影响的分子化合物。 这些化合物可用于捕获猎物，如某些蛇和蜘蛛，或用于防御，如某些昆虫。 最近发现，一种被称为“刺客蝽”的昆虫的热变性唾液中残留着一种强效的快速神经毒性，这种昆虫会向捕食性较大的昆虫喷射这种有毒的唾液，从而导致快速麻痹。 这种毒性活性似乎来自非酶肽。 这项探索性研究的小额资助旨在分离、纯化和鉴定神经活性成分，以便与已知的神经活性肽进行比较，并通过对昆虫神经肌肉制剂的药理学研究来确定其作用模式。 工作假设是，活性成分是作用于神经肌肉接头的肽，或者通过作用于特定通道或通过产生膜孔来总体去极化膜。 这项工作开辟了一个潜在的大新研究领域，因为我们了解一些来自蜘蛛、一些来自黄蜂和蜜蜂的神经毒性毒液，但对其他昆虫神经毒素几乎一无所知。 这项工作在神经科学中的潜在影响很大，因为少数几个已明确表征的已知毒素已经产生了有关神经细胞膜分子结构的特别有用的信息。 这种新的毒液可能具有新颖的分子特性，并且易于收集的毒液数量远远大于其他昆虫或蜘蛛毒素，这可能会成为药理学的廉价商业来源。 这项工作对生态学的影响也可能很大，因为它将提出有关昆虫毒液分子进化以及昆虫防御策略进化发展的问题。

IBN-9727532 PI: EDWARDS Some animals can produce venom that includes not only slowly acting enzymes, but very rapidly acting neurotoxins, which are molecular compounds that have drastic effects on the signalling or transmission properties of nerve cells. These compounds may be used for prey capture, as in some snakes and spiders, or for defense, as in some insects. Recently it has been discovered that a potent rapid neurotoxicity remains in heat-denatured saliva of an insect called the assassin bug, which squirts this venomous saliva at predatory larger insects, causing rapid paralysis. This toxic activity appears to be from non-enzymatic peptides. This Small Grant for Exploratory Research is to isolate, purify and identify neuroactive components for comparison with known neuroactive peptides, and to establish their mode of action using pharmacological studies on insect nerve-muscle proparations. The working hypothesis is that the active components are peptides that act at the neuromuscular junction, or act to generally depolarize membranes by acting on specific channels or by creating membrane pores. This work opens a potentially large new area of research, because we know about some neurotoxic venoms from spiders and some from wasps and bees, but virtually nothing about other insect neurotoxins. The potential impact of this work in neuroscience is high because the few well-characterized known toxins have led to particularly useful information about the molecular structure of nerve cell membranes. This new venom may have novel molecular properties, and the amounts of readily collectable venom are far greater than for other insect or spider toxins, which could lead to an inexpensive commercial source for pharmacology. The impact of this work in ecology is also likely to be high because it will open questions about molecular evolution of insect venoms as well as evolutionary development of insect defense strategies.