INSECT DIURETIC HORMONSES--STRUCTURES AND FUNCTION

昆虫具有低压循环系统，需要利尿激素(DH)来控制马氏管的尿液产生速度。与CRF相关的有13个类似的水解酶，但其结构比CRF超家族的结构更多样化。在这个项目中，很明显，许多物种都有两个水母细胞，这两个物种是近缘关系的，但属于近亲亚科。我们计划继续调查，以继续调查在疾病媒介多刺罗德尼线虫中似乎属于这个卫生组织家族的两个成员。激肽是另一个控制利尿的小肽家族。它们都有相当保守的C末端五肽基序，并已被发现在几种昆虫中与CRF样水解酶具有协同作用。我们建议从R.prolixus和Manduca sexta中识别激动素；这些昆虫代表了饮食习惯不同的物种，前者是专性的血液摄食者，后者是植食性的。我们计划研究这些多肽与这两个物种的马氏管的相互作用及其分子作用模式。激肽是另一个控制利尿的小肽家族。它们都有一个相当保守的C末端五肽基序，并已被发现在几种昆虫中与CRF样水解酶具有协同作用。我们建议从R.prolixus和Manduca sexta中识别激动素；这些昆虫代表了饮食习惯不同的物种，前者是专性的血液摄食者，后者是植食性的。我们计划研究这种专性的血液喂食者和后者是植食性的相互作用。我们计划研究这些多肽与这两个物种的马氏管的相互作用及其分子作用模式。在之前的资助期间，从蟑螂身上发现了一种特别新颖的DH，以及一种类似CRF的DH。这种新的水解酶被证明在结构和功能上与脊椎动物的降钙素有关。同种多肽(Dippu-DH31)与类CRF水解物具有很强的协同作用。由于这种多肽的高效性，对相关物种有很强的协同作用。由于该多肽对相关昆虫物种具有很高的效力，它很可能构成另一个重要的水解酶家族。将在其他物种中研究这种水解物的同源物的存在，包括异种罗非鱼。这些多肽对靶组织的影响将在分子水平上进行研究。Sexta可能至少有两个受体与其类似2CRF的二氢呋喃脱氢酶结合；一个受体已经确定，其他受体的特征将继续进行。识别的受体上的配基结合部位将通过蛋白质交联法和分子生物学方法来接近。

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.