RUI: Amphibian Olfaction: Morphological and Molecular Adaptation Across the Water-to-Land Transition

两栖动物的蜕变提供了一个独特的机会来了解从水生环境适应到陆地环境所必需的变化。在一生中，两栖动物必须经历结构和生理上的变化，才能完成我们的祖先花了数百万年才完成的转变。这个项目的目标是确定两栖动物鼻子的结构和分子特征，使其适应空气和水的气味。本研究将采用组织学、扫描电子显微镜和透射电子显微镜对代表性的蝾螈、蜈蚣、青蛙和肺鱼（四足动物的近亲）的幼体和成体鼻子的详细结构进行研究。此外，编码气味受体蛋白的基因（实际结合和响应气味的蛋白质）将从这些物种中克隆出来，基因表达的阶段和鼻子的区域也将被确定。最后，将使用重要染料进行实验，以确定活体动物鼻子的哪些区域暴露在水和空气中。这项研究的结果将为两栖动物嗅觉系统的变质变化以及成年鼻子闻水的适应性提供第一个广泛的概述。这项研究将大大提高我们对嗅觉系统变化的理解，这种变化发生在两栖动物的祖先身上，因此也发生在我们自己的祖先身上；此外，在本科院校（RUI）进行的这项研究将为本科生提供一个重要的机会，以获得吸引他们从事科学事业所需的经验、技能和观点，并为他们做好准备。

Amphibian metamorphosis provides a unique opportunity to understand the changes necessary to adapt from an aquatic to a terrestrial environment. Within a single lifetime, an amphibian must undergo structural and physiological changes that allow it to make the transition that took our ancestors millions of years. The goal of this project is to determine the structural and molecular features of the amphibian nose that adapt it to smelling in air vs. water. In this study, the detailed structure of the nose in larvae and adults of a representative salamander, caecilian, and frog, and lungfish (the closet living relative of tetrapods) will be examined by histology, scanning electron microscopy, and transmission electron microscopy. In addition, the genes that code for odorant receptor proteins (the proteins that actually bind and respond to smells) will be cloned from each of these species and the stages and regions of the nose in which the genes are expressed determined. Finally, experiments with vital dyes will be used to determine which regions of the nose are exposed to water vs. air in living animals. The results from this study will provide the first broad overview of metamorphic changes in the amphibian olfactory system, and of adaptations of the adult nose for smelling water. This research will significantly enhance our understanding of the changes in the olfactory system that occurred in the ancestry of amphibians, and thus in our own ancestry; in addition, this research at an undergraduate institution (RUI) will provide an important opportunity for undergraduate to gain the experience, skills and perspective needed to attract them to, and prepare them for, a career in science.