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苏酸甲酯(MF)，这是一种由下颌器官(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，眼柄产生一种多肽(MO-抑制激素，MO-IH)，在体外可以抑制MO产生的MF，但尚未表明MO-IH在体内调节MF的产生。这项提案中描述的研究将在青蟹(Carcinus Maenas)中探索这些问题。将通过给蟹注射MF(提高MF水平)和/或纯化的MO-IH(降低MF水平)来研究MF的生理作用(S)。在输注MF和/或MO-IH之前，一些动物将被转移到稀释的海水中，这会导致MF水平的慢性上升。这些程序将被用来检验MF调节渗透压并刺激卵巢和睾丸发育的假说。纯化的MO-IH还将用于制备MO-IH的抗血清，这些抗血清将用于开发该肽的免疫学试验。通过测定不同生理状态下蟹血淋巴中MO-IH和MF的含量，验证MO-IH调节血淋巴中MF水平的假说。这些研究将回答有关MF在这一重要动物群体的生理和发育中所扮演的角色的基本问题。研究结果可能有助于制定战略，以提高珍贵甲壳类动物(如虾)的生长速度和繁殖力，从而使消费者和水产养殖业受益。最后，这些研究中的许多将由本科生完成，为他们提供在学年和暑期较长时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.