INSECT DIURETIC HORMONSES: STRUCTURES AND FUNCTION

昆虫有低压循环系统，需要利尿激素（DH）来控制马尔比氏小管的尿产率。有13个类似的DH与CRF相关，但结构比CRF超家族多样化得多。在这个项目中，很明显，许多物种有两个DH，这两个DH是相关的，但属于副纲的亚科。我们计划继续调查，继续调查似乎是这个DH家族的两个成员在疾病媒介长角Rhodnius。激肽是另一类控制利尿的小肽。它们共享相当保守的c端五肽基序，并在几种昆虫中发现与crf样DH具有协同作用。我们建议从长尾草（R. prolixus）和长尾草（Manduca sexta）中鉴定激宁蛋白；这些昆虫代表了具有不同饮食习惯的物种，前者是专性吸血动物，后者是植食动物。我们计划研究这些肽在两种马氏小管上的相互作用及其分子作用模式。激肽是另一类控制利尿的小肽。它们共享一个相当保守的c端五肽基序，并在几种昆虫中发现与crf样DH具有协同作用。我们建议从长尾草（R. prolixus）和长尾草（Manduca sexta）中鉴定激宁蛋白；这些昆虫代表了具有不同饮食习惯的物种，前者是专性吸血动物，后者是植食动物。我们计划研究这种专性吸血动物和后者是植食性的相互作用。我们计划研究这些肽在两种马氏小管上的相互作用及其分子作用模式。在之前的资助期间，从蟑螂中鉴定出一种特别新颖的DH，点状双翅目，以及类似crf的DH。这个新的DH被证明在结构和功能上与脊椎动物的降钙素有关。多肽（Dippu-DH31）与来自同一物种的crf样DH具有很强的协同作用。由于该肽效力高，对相关物种有很强的协同作用。由于该肽对相关昆虫物种的高效力，它很可能构成DH的另一个重要家族。该DH同源物的存在将在其他物种中进行研究，包括长尾草。这些多肽对靶组织的影响的研究将在分子水平上进行。sexta可能至少有2个受体来表达它的2crf样DH；已经确定了一种受体，并将继续努力表征其他受体。鉴定受体上的配体结合位点将通过蛋白质交联和分子生物学方法进行研究。

Insects have low pressure circulatory systems and require diuretic hormones (DH) to control rate of urine production by Malpighian tubules. There are 13 similar DH related to CRF, but with far more diverse structures than the CRF superfamily. It has become apparent during this project that many species have two DH which are related but belong to sub-families of paralogues. We plan to continue investigating to continue investigating what appears to be two members of this family of DH in the disease vector Rhodnius prolixus. The kinins are another family of small peptides that control diuresis. They share rather conserved C-terminal pentapeptide motif and have been found to have synergistic effects with the CRF-like DH in several species of insect. We propose to identify kinins from R. prolixus and Manduca sexta; these insects represent species with disparate dietary habits, the former being an obligate blood feeder and the latter being phytophagous. We plan to study the interactions of these peptides on Malpighian tubules of the two species and their molecular mode of action. The kinins are another family of small peptides that control diuresis. They share a rather conserved C-terminal pentapeptide motif and have been found to synergistic effects with the CRF-like DH in several species of insect. We propose to identify kinins from R. prolixus and Manduca sexta; these insects represent species with disparate dietary habits, the former being an obligate blood feeder and the latter being phytophagous. We plan to study the interaction of this obligate blood feeder and the latter being phytophagous. We plan to study the interactions of these peptides on Malpighian tubules of the two species and their molecular mode of action. During the prior grant period a particularly novel DH was identified from a cockroach, Diploptera punctata, along with a CRF-like DH. This new DH proved to be structurally and functionally related to calcitonin in vertebrates. The peptide (Dippu-DH31) and the CRF-like DH from the same species have strongly synergistic effects. Due to the high potency of this peptide on related species have strongly synergistic effects. Due to the high potency of this peptide on related species of insects, it may well constitute an additional important family of DH. The existence of homologues of this DH will be investigated in other species, including R. prolixus. Studies of the effects of such peptides on the target tissue will be pursued at the molecular level. It is probable that M. sexta has at least 2 receptors for its 2CRF-like DH; one receptor has been identified and efforts to characterize other receptors will be pursued. The ligand binding site on the identified receptor will be approached by protein cross-linking and molecular biological approaches.