Studies of Methyl Farnesoate in Crustaceans: Physiological Significance and Peptide Regulation

甲壳类动物有丰富多样的激素来调节它们的生理、发育、繁殖和行为。其中一种化合物似乎是法尼酸甲酯（MF），一种由下颌器官（MO）产生的倍半萜。最近的研究表明，MF可能会影响甲壳类动物的生长和繁殖，但这些研究并没有明确证明这些作用。其他研究表明眼柄产生一种肽（MO-抑制激素，MO- ih），可以在体外抑制MO对MF的产生，但尚未证明MO- ih在体内调节MF。本提案中所描述的研究将探讨绿蟹（Carcinus maenas）的这些问题。将通过给螃蟹注射MF（增加MF水平）和/或纯化的MO-IH（降低MF水平）来研究MF的生理作用。一些动物将被转移到稀释的海水中，这将导致MF水平的慢性上升，然后再注入MF和/或MO-IH。这些程序将用于测试MF调节渗透调节和刺激卵巢和睾丸发育的假设。纯化的MO-IH还将用于开发MO-IH的抗血清，这些抗血清将用于开发该肽的免疫学检测。我们将在不同生理状态的蟹血淋巴中检测MO-IH和MF，以验证MO-IH调节MF血淋巴水平的假设。这些研究将回答关于MF在这一重要动物群体的生理和发育中的作用的基本问题。这些结果可能有助于设计提高有价值甲壳类（如虾）的生长速度和繁殖能力的策略，从而使消费者和水产养殖业受益。最后，许多这些研究将由本科生进行，为他们提供在学年和夏季延长期间学习科学的实践机会。

Crustaceans have a rich diversity of hormones that regulate their physiology, development, reproduction, and behavior. One of these compounds appears to be methyl farnesoate (MF), a sesquiterpene produced by the mandibular organ (MO). Recent research suggests that MF may affect crustacean growth and reproduction, but these studies do not definitively prove these roles. Other research has shown that the eyestalk produces a peptide (MO-inhibiting hormone, MO-IH) that can inhibit the production of MF by MO in vitro, but it has not been shown that MO-IH regulates MF in vivo. The research described in this proposal will explore these issues in the green crab, Carcinus maenas. The physiological role(s) of MF will be investigated by infusing crabs with MF (to increase MF levels) and/or with purified MO-IH (to decrease MF levels). Some animals will be transferred to dilute seawater, which causes a chronic rise in MF levels, before infusion with MF and/or MO-IH. These procedures will be used to test hypotheses that MF regulates osmoregulation and stimulates ovarian and testicular development. Purified MO-IH will also be used to develop antisera to MO-IH, and these antisera will be used to develop immunological test for this peptide. MO-IH and MF will be measured in hemolymph from crabs in different physiological states to test the hypothesis that MO-IH regulates hemolymph levels of MF. These studies will answer fundamental questions about the roles of MF in the physiology and development of this important group of animals. The results may be useful in designing strategies to increase the growth rate and reproductive fecundity of valuable crustaceans (e.g. shrimp), which could benefit consumer and the aquaculture industry. Finally, many of these studies will be performed by undergraduate students, providing them with a hands-on opportunity to learn science during the academic year and for extended periods during the summer.