US-UK Dissertation Enhancement: Evolution of Unusual Steroids in Lamprey Species

这个美英论文强化项目由密歇根州立大学的李伟明、博士生Mara Beth Bryan和英国环境、渔业和水产养殖科学中心的Andrew Scott共同参与。该奖项支持博士生进行为期两个月的访问，以调查欧洲河七鳃鳗（Lampetra fluviatillis）中不寻常的15a-羟基化类固醇的存在和可能的功能。这一研究方向加强了论文目前对海七鳃鳗（Petromyzon marinus）中15a-羟化类固醇的结构和功能的研究。目的是确定15a-羟化类固醇（性腺类固醇）是否祖先和普遍在七鳃鳗通过调查他们的作用在欧洲河七鳃鳗，最衍生的七鳃鳗属。目的是研究七鳃鳗体外性腺组织中的类固醇，体内类固醇循环和产生，类固醇水平随GnRH给药的变化。由于七鳃鳗是已知最早进化为下丘脑-垂体-性腺轴的脊椎动物，因此对七鳃鳗体内激素的研究对其内分泌功能的进化和生物多样性具有重要意义。然而，大多数研究都集中在下丘脑和垂体的激素上，并且只对一个物种——海七鳃鳗进行了研究。本论文项目将这些研究扩展到几种不同物种的性腺类固醇。该项目利用了英国独特的设施，那里有七鳃鳗。研究结果将有助于进一步了解世界不同地区濒临灭绝、受威胁或被视为入侵物种的各种七鳃鳗的保护和控制工作。

0336929LiThis U.S.-U.K. dissertation enhancement project involves Weiming Li of Michigan State University, doctoral student Mara Beth Bryan, and Andrew Scott of the U.K. Centre for Environment, Fisheries and Aquaculture Science. The award supports a two-month visit by the doctoral student to investigate the presence and possible functionality of unusual 15a-hydroxylated steroids in European river lamprey (Lampetra fluviatillis). This line of research enhances the dissertation effort currently focused on the structure and functionality of 15a-hyroxylated steroids in the sea lamprey (Petromyzon marinus). The goal is to determine if the 15a-hyroxylated steroids (gonadal steroids) are ancestral and universal in lampreys by investigating their role in the European river lamprey, the most derived lamprey genus. The objectives are to study the steroids in the river lamprey's gonadal tissues in vitro, steroid circulation and production in vivo, changes in steroid levels in response to GnRH administration. Research on steroids in lampreys has implications in evolution and biodiversity of endocrine functions, as lampreys are the earliest evolving extant vertebrate studied for the hypothalamus-pituitary-gonadal axis. However, most research has focused on hormones of the hypothalamus and pituitary, and has been conducted on a single species, the sea lamprey. This dissertation project extends these studies to gonadal steroids in several different species. The project takes advantage of access to unique facilities in the United Kingdom which house river lampreys. The results will further understanding of conservation and control efforts for various lamprey species, which in different parts of the world are endangered, threatened, or considered as an invasive species.