Bio-organic Chemistry on Egg Diapause of Silkworm

天然SGNP和新的滞育诱导物质的研究从家蚕食管下神经节提取物中寻找天然α-、β-和γ-SGNP。为了研究新的滞育诱导物质，收集了雄蚕蛾的头部，对α-和γ-SGNP进行了分离和鉴定，并推测存在β-SGNP。它们用水和几种有机溶剂萃取。大部分提取物具有诱导滞育的活性，说明该器官含有多种活性物质。通过重复色谱法纯化它们，并分离出活性物质之一（VAP肽）。滞育激素（Diapause hormone，DH）是一种具有生物活性的多肽，具有独特的结构、理化性质和生物活性。因为当游离DH分子简单地用衍生试剂处理时，生物活性降低。成功地制备了酰化衍生物、荧光和色素衍生物以及光亲和标记衍生物，合成了C端五肽及其类似物，并比较了它们的生物活性。结果表明：（1）C端的酰胺结构是重要的，（2）三肽酰胺是生物学功能的最小单元，（3）对该单元进行修饰可增强生物活性，为阐明滞育诱导机制和设计、合成人工诱导滞育物质提供了可能。

SEARCH FOR NATURAL SGNPS AND NEW DIAPAUSE INDUCING SUBSTANCESNatural alpha-, beta- and gamma-SGNP were searched for in the extract of the suboesophageal ganglions of silkworm. alpha- and gamma-SGNP were isolated and identified, and beta-SGNP was speculated to exist.To investigate the new diapause inducing substances, the heads of male silk moths were collected. They were extrated with water and several organic solvents. Most of the extracts showed the diapause inducing activity, and the result suggested that the organ contains many kinds of active substances. They were purified by repeated chromatography and one of the active substances (VAP peptide) was isolated. It had unique structure, physicochemical feature and biological activity.PEPTIDE SYNTHESIS AND BIOLOGICAL ACTIVITY OF SYNTHETIC PEPTIDESDiapause hormone (DH) , SGNPs and a fragment analog of VAP peptide were chemically synthesized and the synthetic peptides were used for preparation of antibodies and for the preparation of derivatives.A procedure to derivatize the N terminus of DH was developed, as the biological activity was reduced when free DH molecule was simply treated with the derivatizing reagents. Acylated derivatives, fluorescent and pigmented derivative and photoaffinity labeled derivative were successfully prepared.The C terminal pentapeptides and their analogs were synthesized and their biological activities were compared to each other. The result suggested 1) amide structure at C terminus is important, 2) the tripeptide amide is the smallest unit for biological function, 3)modification of the unit enhances the biological acitivity.The results of the present research indicated the possiblility to clarify the mechanism for diapause induction and to design and to create the artificial diapause inducing substances.