Characterization of a Family of Pheromonal Attractants

动物使用各种各样的信号来协调它们与同类其他成员的活动。这些信号中有些是视觉信号（如鲜艳的颜色或姿势），有些是口头信号（如唱歌、咆哮或呜咽），还有一些是化学信号（如标记领地或诱导产卵）。这种化学信号被称为信息素，迄今为止，对昆虫的研究最为彻底。信息素参与协调水生动物的活动，但对这些物质的化学特性或特定活性知之甚少。水传播的肽信息素尤其如此，它们很难分离和表征，因为：(a)在任何时候只有少数动物分泌信息素；(b)对诱导信息素分泌的刺激知之甚少；(c)分泌相对少量的信息素；(d)在接触过各种动物及其产品的大量水中产生分泌物；(e)信息素被迅速降解的可能性很大。海洋软体动物阿普里亚生殖系统的两个特点，使解决这些问题成为可能。例如，注射产卵激素会使小绒猴产下一长串卵（卵带），这是信息素的来源，吸引其他动物到该地区，并诱导它们产卵和/或交配。这种诱导产卵的有用工具使控制产卵动物的数量、产卵的时间和同步、产卵的一般区域以及周围海水的相对纯度成为可能。利用海百合，分离出一种水溶性肽信息素（“吸引素”），并对其进行了化学表征。该信息素在实验室生物测定中具有多种活性，属于不同种类的海百合和其他水生腹足类动物的吸引相关肽家族。本课题将运用分子、生化和行为学等技术对以下三个假设进行验证：(1)在其他种类的海百合（applysia）、其他类目（bur卫星目）和水生肺藻（lynaea）中存在吸引素相关肽信息素。(2)卵带是多种信息素引诱剂的来源。(3)牡蛎中有一种肽信息素家族可以引发大量产卵。海兔吸引及其相关肽的生物化学和行为特征将有助于了解信息素对软体动物生殖行为的调控；肽信息素及其功能的研究吸引的活跃部位；以及吸引受体的性质和作用机制。

Animals use a variety of signals to coordinate their activity with that of other members of their species. Some of these signals are visual (e.g., bright colors or posturing), others are verbal (e.g., singing, growling, or whimpering), and still others are chemical (e.g., marking territories or inducing spawning). The chemical signals are known as pheromones, which to date have been most thoroughly investigated in insects. Pheromones are involved in coordinating the activities of aquatic animals, yet little is known about the chemical identities or specific activities of these substances. This is particularly true of water-borne peptide pheromones, which are difficult to isolate and characterize because: (a) only small numbers of animals secrete pheromones at any one time; (b) little is known about the stimulus that induces pheromone secretion; (c) relatively small amounts of pheromones are secreted; (d) secretion occurs into large volumes of water that has contacted a variety of animals and their products; and (e) there is a strong possibility that the pheromone is rapidly degraded.Two characteristics of the reproductive system in Aplysia, a marine mollusk, make it possible to address some of these problems. For example, injection of egg laying hormone causes Aplysia to lay a long string of eggs (an egg cordon), which is the source of pheromones that attract other animals to the area and induce them to lay eggs and/or mate. This useful tool to induce egg laying makes it possible to control the number of animals laying eggs, the timing and synchronization of egg laying, the general area where eggs are deposited, and the relative purity of the surrounding seawater. Using Aplysia, a water-borne peptide pheromone ("attractin") has been isolated and chemically characterized. This pheromone has multiple activities in laboratory bioassays and belongs to a family of attractin-related peptides in different species of Aplysia and perhaps other aquatic gastropods.The experiments in this proposal will use molecular, biochemical and behavioral techniques to test three hypotheses: (1) There are attractin-related peptide pheromones in other species of Aplysia, in other opisthobranchs (Bursatella), and in aquatic pulomonates (Lymnaea). (2) Egg cordons are a source of multiple pheromonal attractants. (3) There is a family of peptide pheromones that trigger mass spawning in oysters.Biochemical and behavioral characterization of Aplysia attractin and related peptides will contribute to understanding of pheromonal regulation of reproductive behavior in mollusks; of peptide pheromones and their function(s); of attractin's active site; and the nature and mechanism of action of the attractin receptor.