Novel Perireceptor Role for Harderian Gland in Vomeronasal System

信息素的化学通讯是大多数脊椎动物信息传递的主要方式。雌性束带蛇（Thamnophis sirtalis）性信息素是饱和和单不饱和甲基酮的非极性疏水混合物，不溶于水溶液。这种信息素被犁鼻器（VNO）检测到，犁鼻器专门用于接收非挥发性化学线索，但信息素进入器官的水环境的机制尚不清楚。初步数据表明，哈氏腺（HG）的分泌物，专门管道到VNO在蛇，含有增溶和/或信息素结合的属性。300多年来，头部HG的功能一直是众多来源推测的主题。 当然，他们相对较大的尺寸，他们的系统发育年龄，并持续保护几乎所有的四足动物群体，因为他们出现了从水到空气/陆地环境表明，他们可能发挥了重要作用，在生理适应陆地生活。 本研究将探讨HG作为一种媒介，在提供访问的雌性信息素的雄性束带蛇的VNO的作用。 使用放射性标记的束带蛇性信息素，研究将进行确定HG分泌物对雌性信息素的增溶作用和HG分泌物具有信息素结合蛋白的潜力。 HG去除求爱行为和猎物攻击的影响，这两个已知的需要一个功能VN系统，也将进行调查，将季节性和激素变化的影响的HG的组成。这里描述的综合研究将提供一种新的机制，其中非极性，疏水性信息素分子达到的VNO，使用一个非常好的特点系统：吊袜带蛇VN系统的演示。 如果涉及信息素结合蛋白，这将是第一个在非哺乳动物物种中发现的。 这项研究将提供一个令人信服的模型，检查HG参与介导的VNO功能的其他哺乳动物和非哺乳动物的外周事件。 此外，这项研究利用了一个物种在其自然栖息地中表现出的两种明确的、可量化的行为，不仅为深入了解生殖行为和摄食的季节性变化提供了一个强大的模型，而且还提出了一种调节这些季节性变化的生理机制。 这项建议涉及一个综合的，多学科的方法，包括现场和实验室研究，将产生显着的见解，许多共同的信息素通信的统一原则，如果不是大多数，脊椎动物。这一建议的更广泛影响包括通过指导研究生、本科生和向高中和小学生推广，在研究和教育方面进行多学科培训。 本科生是PI实验室不可或缺的一部分，协助畜牧业，野外工作和行为实验。 这些本科生是这两个实验室发表的23篇论文的合著者。 PI长期致力于指导，有十几名高中生参与少数民族培训计划和英特尔/西屋竞赛，另有九名高中生参加了NSF发起的科学和工程学徒计划。 这些经验，加上适当的课程工作，将提供一个坚实的基础，这些科学家在培训中体验的喜悦和挫折的实地和实验室工作。

Chemical communication by pheromones is the predominant mode of information transfer in most vertebrates. The female garter snake (Thamnophis sirtalis) sex pheromone, a nonpolar, hydrophobic blend of saturated and monounsaturated methyl ketones, is insoluble in aqueous solutions. This pheromone is detected by the vomeronasal organ (VNO), which is specialized for the reception of nonvolatile chemical cues, but the mechanism by which the pheromone gains access to the aqueous environment of the organ is unknown. Preliminary data indicate that the Harderian glands' (HG) secretions, which duct exclusively into the VNO in snakes, contain solubilizing and/or pheromone-binding properties. For over 300 years, the function of the cephalic HG has been the subject of speculation from numerous sources. Certainly their relatively large size, their phylogenetic age, and persistent conservation in almost all tetrapod groups as they emerged from an aqueous to an air/land environment suggest that they probably play an important role in the physiological adaptation to terrestrial life. This project will examine the role of the HG as a mediator in providing access for the female sex pheromone to the VNO of male garter snakes. Using radiolabeled garter snake sex pheromone, studies will be conducted to determine the solubilizing effect of HG secretion on the female sex pheromone and the potential of the HG secretion to possess pheromone-binding proteins. The effects of HG removal on courtship behavior and prey attack, both known to require a functional VN system, will also be investigated, as will the effects of seasonal and hormonal variation on the composition of the HG. The integrative research described here will provide demonstrations of a novel mechanism by which nonpolar, hydrophobic pheromone molecules reach the VNO, using a very well characterized system: the VN system of garter snakes. If a pheromone-binding protein is involved, it will be the first identified in a non-mammalian species. This research will provide a compelling model for the examination of HG involvement in perireceptor events mediating VNO function of other mammalian and non-mammalian vertebrates. In addition, this study takes advantage of two unambiguous, quantifiable behaviors exhibited by a species in its natural habitat that not only offers a robust model for insights into seasonal shifts in reproductive behavior and feeding, but also proposes a physiological mechanism mediating these seasonally regulated changes. This proposal involves an integrative, multidisciplinary approach including field and lab studies that will yield significant insights into the unifying principles of pheromonal communication common to many, if not most, vertebrates. The broader impacts of this proposal include multidisciplinary training in research and education through the mentoring of graduate students, undergraduates and outreach to high school and grade school students. Undergraduates are an integral part of the PI's laboratories, assisting in animal husbandry, field work and behavior experiments. These undergraduates have been co-authors on 23 published papers from the two laboratories. The PI's have a long-term commitment to mentoring, with more than a dozen high school students involved in minority training programs and Intel/Westinghouse competitions, and an additional nine high school students having worked in an NSF-initiated Apprenticeships in Science and Engineering program. These experiences, coupled with appropriate course work, will provide a firm foundation for these scientists-in-training to experience the joys and frustration of field and laboratory work.