IDENTIFICATION OF THE TICK JUVENILE HORMONE

保幼激素(JH)是节肢动物的重要调节元件 发展和繁殖。然而，我们对这种荷尔蒙的理解 几乎完全集中在昆虫身上。在扁虱中，没有内分泌腺 已经毫不含糊地确定了JH的存在 假设的。这种基本信息的缺乏是对 这一组中的科学研究。考虑到在医学上的重要性 扁虱在疾病传播中的作用及其潜在应用 病虫害防治中的硬虱生理学知识，鉴定研究 扁虱JH应具有与人类相关的重要实用价值 健康。 在对美国狗扁虱的研究中，我们发现 成年联会神经节与3/H-蛋氨酸的体外孵育 释放到JH III和JH III的双环氧化物孵育介质中。 我们早期用放射免疫法检测到血淋巴中的JH III 喂给成年人，但双环氧化物没有被研究。一个特定的JH 在若虫和成虫中初步鉴定出酯酶。 血液喂养似乎涉及内源性的清除 JH之前出现蜕皮性类固醇。 这项建议的目的是鉴定JH样激素(S)和 它们在扁虱体内生物合成的位置。这将通过以下方式实现 粉纹夜蛾若虫个体组织的体外孵化 和成人发育，用放射性标记的前体识别 昆虫JHS。将用层析方法鉴定推定的扁虱JH(S)， 化学衍生化、酶衍生化和GC-MS联用。来自血淋巴的JH(S) 将用GC-MS测定喂血成虫的含量，并测定生物活性 用几种不同的生物测定方法评估了JH(S)的感染情况。JH 生物合成将在若虫和成虫发育期间进行测量，并 与JH代谢相关。

Juvenile hormone (JH) is an important regulatory element in Arthropod development and reproduction. However, our understanding of this hormone has centered almost exclusively on insects. In ticks, no endocrine gland has been unambiguously identified and the presence of JH is still hypothetical. This lack of basic information is an impedance to scientific research in this group. Considering the medical importance of ticks in disease transmission and the potential application of our knowledge of tick physiology in pest management, studies on identifying the tick JH should have significant practical value related to human health. In studies with the American dog tick, Dermacentor variabilis, we found that adult synganglia incubated in vitro with 3/H-methionine apparently released into the incubation medium JH III and the bisepoxide of JH III. Our earlier studies using RIA detected JH III in the hemolymph of blood fed adults but the bisepoxide was not investigated. A specific JH esterase was tentatively identified in nymphs and adults at the time of blood feeding which appeared to be involved in the removal of endogenous JH prior to the appearance of ecdysteroids. The objective of this proposal is to identify JH-like hormone(s) and the site of their biosynthesis in ticks. This will be achieved through in vitro incubations of individual tissues of D. variabilis during nymphal and adult development with radiolabeled precursors used to identify the insect JHs. The putative tick JH(s) will be identified by chromatography, chemical and enzyme derivatization, and GC-MS. JH(s) from the hemolymph of blood fed adults will be determined by GC-MS, and biological activity of the JH(s) assessed in ticks with several different bioassays. JH biosynthesis will be measured during nymphal and adult development and correlated with JH metabolism.