RUI: Smelling in water and air: Evolution of olfaction in plethodontid salamanders

RUI：在水和空气中嗅觉：无齿蝾螈嗅觉的进化

• 批准号: 2050018
• 负责人: John Reiss
• 金额: $ 39.76万
• 依托单位: Humboldt State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050018&HistoricalAwards=false
• 关键词: RUI; Smelling; water; air; Evolution

This project focuses on how the olfactory system of amphibians is modified to function in water and in air. The emergence of vertebrate animals from water onto land was one of the major transitions of vertebrate evolution. For many living amphibians, this historical transition is mirrored by a current developmental transition, as they metamorphose from an aquatic larva to a terrestrial juvenile. Like other sensory systems, the olfactory system must be able to adjust and function in both environments across this developmental transition. This project breaks new ground by examining olfactory morphology and gene expression patterns across eight related salamander species with a wide range of life histories, ranging from typical larvae with metamorphosis, to direct development with no free-living larval stage, to secondarily re-evolved larvae. The study will answer the following questions: (1) Are patterns of olfactory organization consistent across species with the same developmental mode, regardless of evolutionary history? (2) Are water-sensing olfactory components lost in terrestrial, direct-developing species? (3) Do species that have re-evolved a larval period regain water-sensing olfactory components? This work will take place at Humboldt State University, an Hispanic Serving Institution located on the rural northern coast of California. It will directly support 15-20 undergraduate and two graduate students in hands-on research, enhancing their skills and thereby furthering their careers and job prospects. The research will be integrated into classes, benefitting approximately 300 students per year. A public outreach component will involve lectures to local community members, increasing scientific literacy on evolution and development and promoting appreciation for this understudied group of vertebrates.This project will examine how the evolution of alternative developmental modes impacts olfactory system structure and function in the most speciose family of salamanders, the plethodontid or lungless salamanders. Olfactory morphology and gene expression patterns of eight plethodontid species and one outgroup species that span a wide range of developmental modes will be examined. Techniques used will include traditional histology to compare the basic structure of the olfactory organs, transmission and scanning electron microscopy to establish morphological classes of olfactory receptor neurons and supporting cells, microCT scanning and 3-D reconstruction to provide a visual image of overall olfactory organ anatomy, neuronal tracing to establish pathways of olfactory receptor neuron connection to the brain, and protein and mRNA localization of olfactory marker genes. This work will for the first time elucidate patterns of olfactory evolution with respect to olfaction in water and air, in larvae and adults, within an explicit phylogenetic framework. By doing so, it will allow a better understanding of how the olfactory system evolves in living amphibians, and of changes associated with the evolutionary emergence of tetrapods onto land. A total of 15-20 undergraduates and two graduate students will participate directly in the project, and the research will be incorporated into five courses that enroll approximately 300 students. The research will also be presented to the public at the institution’s natural history museum and at a science lecture series at a local coffeehouse.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目着重于如何修改两栖动物的嗅觉系统以在水和空气中发挥作用。脊椎动物从水到陆地的出现是脊椎动物进化的主要过渡之一。对于许多活着的两栖动物而言，这种历史过渡是由当前的发展过渡反映的，因为它们从水生幼虫变成了陆地幼年。与其他感觉系统一样，嗅觉系统必须能够在此发展过渡的两个环境中调整和运行。该项目通过检查八个相关的sal虫物种的嗅觉形态和基因表达模式来打破新的基础，这些植物具有广泛的生活历史，从典型的幼虫到具有变质的典型幼虫到没有自由生活的幼虫阶段的直接发育，到次生再发展的幼虫。该研究将回答以下问题：（1）无论进化历史如何，嗅觉组织的模式是嗅觉组织一致的，无论是相同的发育模式吗？ （2）在陆地直接开发物种中丢失了水感应嗅觉成分？ （3）重新发展的幼虫时期的物种是否会恢复水感应嗅觉成分？这项工作将在洪堡州立大学（洪堡州立大学）举行，这是位于加利福尼亚州粗糙北海岸的西班牙裔服务机构。它将直接支持15至20岁的本科生和两名研究生进行动手研究，从而提高他们的技能，从而进一步发展其职业和工作前景。该研究将融入课程，每年受益约300名学生。公众的外展部分将涉及当地社区成员的讲座，提高有关进化和发展的科学素养，并促进对这一知识的脊椎动物群体的欣赏。该项目将研究替代发展模式如何影响嗅觉系统的结构和在最斑点的Salamanders家族中，较中的sal，多颗粒化或无肺的Salamandersers。将检查八种多种物种和一种跨越各种发育模式的嗅觉形态和基因表达模式。 Techniques used will include traditional histology to compare the basic structure of the olfactory organs, transmission and scanning electronic microscopy to establish morphological classes of olfactory receptor neurons and supporting cells, microCT scanning and 3-D reconstruction to provide a visual image of overall olfactory organ anatomy, neuronal tracing to establish pathways of olfactory receptor neuron connection to the brain, and protein and mRNA嗅觉标记基因的定位。这项工作将首次阐明在水和空气中，幼虫和成年人，明确的系统发育框架内的嗅觉进化模式。通过这样做，它将可以更好地理解嗅觉系统如何在活着的两栖动物中演变，以及与四足动物在土地上的进化出现相关的变化。共有15-20名本科生和两名研究生将直接参加该项目，该研究将纳入五门课程中，约有300名学生。该研究还将在该机构的自然历史博物馆和当地咖啡馆的科学讲座系列上向公众介绍。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响评估审查标准，被认为是珍贵的支持。