Neurohormone cascades during crustacean ecdysis

所有节肢动物（如昆虫和螃蟹）必须定期脱落外骨骼，以生长和发育。这个过程，称为蜕皮，是在复杂的激素控制。就在蜕皮之前，一系列精确定时的激素“级联”开始，引发一系列行为和形态变化，使动物出现，膨胀到最后（更大的尺寸），并最终硬化外骨骼。对于昆虫，特别是果蝇，果蝇对参与这些过程的激素有很多了解，特别是被称为甲壳动物心脏活性肽和囊体激素的激素，研究得特别好。对于甲壳类动物几乎没有什么是已知的，尽管事实上，甲壳类动物的心脏活性肽，正如它的名字所暗示的，首先在螃蟹中发现！关于bursicon，直到最近我在螃蟹中发现了编码类似bursicon样激素的基因，才完全知道。然而，我们不太了解这些激素如何工作，或者它们在甲壳类动物中的功能，并且由于水生甲壳类动物（即螃蟹）和昆虫（即苍蝇）具有非常不同的生活方式，因此确定这些激素在蜕皮期间如何工作和相互作用将是非常有趣的。这将通过确定激素在螃蟹中枢神经系统神经细胞中的分布和水平来完成，以及它们如何在蜕皮过程中释放，通过使用高灵敏度的分析技术测量释放模式来确定在旧外骨骼出现的精确定时阶段释放的消失的少量激素，以及随着新骨骼的发育和硬化。我还将使用一种强大的技术，称为“RNA干扰”，（这项技术的创始人刚刚获得诺贝尔奖），以减少激素的数量和/或基因表达的水平（囊体激素和甲壳类动物心脏活性肽），或减少螃蟹皮肤中囊体激素受体的数量（昆虫中囊体激素的靶组织），看看我是否能扰乱动物的正常换羽模式和行为，从而揭示激素的功能。最后，我将尝试通过注射激素或药物来“拯救”这些异常的换羽模式，这些激素或药物参与将激素信号传递到参与产生新外骨骼的细胞机制，并观察换羽期间和之后的后续事件。通过这种方式，可以更详细地了解极其复杂的过程--蜕皮。这不仅使我们能够比较两个最大的节肢动物群体之间这些激素作用方式的差异，而且在未来，还可以允许操纵经济上重要的甲壳类动物的蜕皮，以经济上可持续的方式最大限度地提高产量。

All arthropods (such as insects and crabs) must periodically shed their exoskeletons in order to grow and matamorphose. This process, called ecdysis, is under complex hormonal control. Just before ecdysis a precisely timed series of hormonal 'cascades' begin, which set off a series of behavioural and morphological changes allowing the animal to emerge, swell to its final (larger size) and eventually harden the exoskeleton. For insects, and particularly for the fruit fly, Drosophila much is known about the hormones involved in these processes, and in particular, the hormones called crustacean cardioactive peptide and bursicon are particularly well studied. For crustaceans hardly anything is known, despite the fact that crustacean cardioactive peptide was, as its name suggests firstly found in crabs! With regard to bursicon, absolutely nothing was known until very recently, when I discovered genes encoding similar 'bursicon-like' hormones in crabs. However, we do not know much about how these hormones work, or their functions in crustaceans, and since aquatic crustaceans (i.e. crabs) and insects (i.e.flies) have very different lifestyles, it would be fascinating to determine how these hormones work and interact during ecdysis. This will be done by determining the hormones' distribution and levels in the nerve cells in the central nervous system of the crab, and how they are released during ecdysis by measuring patterns of release using highly sensitive assay techniques to determine the vanishingly small amounts of hormones released at precisely timed stages of emergence from the old exoskeleton, and as the new one develops and hardens. I will also use a powerful technique called 'RNA interference' (the founders of this technique have just been awarded a Nobel prize), to reduce the amount of hormones and/or the levels of gene expression (bursicon and crustacean cardioactive peptide) present in the crabs nervous system during moulting, or reduce the numbers of bursicon receptors in the crabs skin (the target tissue for bursicon in insects), to see if I can disrupt the normal moulting pattern and behaviour of the animal, thus shedding light on the functions of the hormones. Finally, I will try to 'rescue' these abnormal moulting patterns by injecting the hormones, or pharmacological agents involved in transmitting the hormonal signal to the cellular machinery involved in producing the new exoskeleton, and observing subsequent events during and after moulting. In this way, a much more detailed understanding of an exquisitely complex process- ecdysis- can be obtained. This will not only allow us to compare differences in the way these hormones act between the two largest arthropod groups, but also may in the future, allow manipulation of moulting in economically important crustaceans, to maximise yield in an economically sustainable way.