Bio-organic Chemistry on Egg Diapause of Silkworm

家蚕食道下神经节提取物中含有天然的α-、β-和γ-SGNP。分离和鉴定了α-和γ-SGNP，推测存在β-SGNP。为了研究新的滞育诱导物质，采集了丝蛾雄蛾的头部。用水和几种有机溶剂提取。大部分提取物具有滞育诱导活性，表明该器官含有多种活性物质。经反复层析纯化，得到一种活性物质(VAP肽)。化学合成了滞育激素、SGNPs和VAP多肽的片段类似物，并将其用于抗体的制备和衍生物的制备。针对游离的滞育激素分子用衍生剂处理后生物活性降低的问题，建立了一种衍生化水杨酸N端的方法。成功地合成了酰化衍生物、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末端的酰胺结构是重要的；2)三肽酰胺是生物功能的最小单位；3)该单位的修饰增强了生物活性。本研究结果表明，有可能阐明滞育诱导的机理，设计和创造人工滞育诱导物质。

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.