RUI: Neural Regulation of Metamorphosis in a Gastropod Mollusc

Pires0110832摘要在大多数动物的生活史中，变形是一个极其重要的转变。从幼虫到幼鱼的转变需要破坏一些组织，重新指定其他组织并产生新的结构。在腹足类软体动物的幼虫和其他门的各种幼虫中，变态是由来自环境的化学信号启动的。腹足类变态的化学感应诱导，其刻板的行为背景和一些形态发生运动的神经肌肉性质，以及形态变化的速度都表明幼虫神经系统的普遍控制。然而，很少有人知道神经系统可以在整个生物体水平上指导戏剧性的形态变化的机制。 皮雷斯博士将研究神经控制的变态腹足类，Crepidula fornicata，专注于神经信号在破坏幼虫帆。在有能力的幼虫与诱导变态的自然线索接触后几分钟内，由于几种类型的膜细胞之间的粘附力丧失，这种纤毛游泳和摄食器官急剧脱落。排列在软膜边缘的大型纤毛细胞是变态中最先分离的，是电兴奋的，并且在其他腹足类动物中已经显示出携带突触驱动的钙介导的动作电位，导致纤毛跳动的停滞。这些纤毛在C.穹窿纲动物和其他腹足类动物在可见的膜破坏开始之前的时刻，但没有研究调查膜中的电活动与变态中发生的细胞粘附丧失之间的机械关系。Pires博士和其他人以前的工作已经暗示内源性多巴胺是一种神经调节剂，可以增强变态，但它对软膜信号的影响尚未探索。 还有证据表明，过氧化氢或其他活性氧在变态软膜中产生，如果外源性应用，可以诱导软膜破坏，但尚不清楚活性氧在自然变态中介导软膜破坏的神经机制中是否具有必要的信号作用。fornicata幼虫，并利用显微外科方法，他开发的工作与孤立的软膜组织。Pires博士和他的学生将应用细胞内和细胞外电生理技术以及药理学，组织化学和高效液相色谱方法来分析神经信号如何影响细胞粘附在变质膜中的快速丧失。这个项目为本科研究生提供了一个不寻常的机会，从事发展神经科学，跨越几个层次的生物组织。这个项目的一个重要的进一步培训方面是，暑期工作将发生在华盛顿的星期五港实验室，本科生将沉浸在一个丰富的和令人振奋的科学社区的时候，他们将对未来的研究生涯的决定。

Pires0110832AbstractMetamorphosis is a profoundly important transition in the life history of most animals. The passage from a larval to juvenile form entails destruction of some tissues, respecification of others and generation of new structures. In larvae of gastropod molluscs and in a diverse range of larvae from other phyla, metamorphosis is initiated by a chemical signal from the environment. The chemosensory induction of gastropod metamorphosis, its stereotyped behavioral context and the neuromuscular nature of some morphogenic movements, and the rapidity of morphological change all suggest pervasive control by the larval nervous system. However, very little is known of the mechanisms by which the nervous system can direct dramatic morphological change at the level of the entire organism. Dr. Pires will investigate the neural control of metamorphosis in the gastropod, Crepidula fornicata, focusing on neural signaling in the destruction of the larval velum. This ciliated swimming and feeding organ is precipitously shed by loss of adhesion among and between several types of velar cells within minutes after competent larvae come in contact with the natural cue that induces metamorphosis. The large ciliated cells that line the margin of the velum are the first to detach in metamorphosis, are electrically excitable, and have been shown in other gastropods to carry a synaptically-driven calcium-mediated action potential that causes arrest of ciliary beating. These cilia are arrested in C. fornicata and other gastropods in the moments before destruction of the velum visibly begins, yet no studies have investigated the mechanistic relationship between electrical activity in the velum and the loss of cell adhesion that occurs in metamorphosis. Previous work by Dr. Pires and others has implicated endogenous dopamine as a neuromodulator that potentiates metamorphosis, but its effects on signaling in the velum are unexplored. There is also evidence that hydrogen peroxide or other reactive oxygen species are generated in the metamophosing velum and can induce velar destruction if exogenously applied, but it is not known if reactive oxygen species have a necessary signaling role in a neural mechanism that mediates velar destruction in natural metamorphosis.Dr. Pires will exploit the large size and predictably fast metamorphosis of C. fornicata larvae, and take advantage of microsurgical methods that he developed for working with isolated velar tissues. Dr. Pires and his students will apply intracellular and extracellular electrophysiological techniques as well as pharmacological, histochemical and high-performance liquid chromatographic methods to analyze how neural signals effect a rapid loss of cell adhesion in the metamorphosing velum. This project affords undergraduate research students an unusual opportunity to engage in developmental neuroscience that cuts across several levels of biological organization. An important further training dimension of this project is that summer work will take place at the University of Washington's Friday Harbor Laboratories, where undergraduates will be immersed in a rich and exhilarating scientific community at a time when they will be making decisions about future research careers.