| Chinese mitten crabs (Eriocheir sinensis) are aquatic products in China. They widely live in fresh water. It is well known for its delicious taste and high nutritive value in world. But many cultured larvae are precocious in scores. It will bring about smaller body and death rate, which constrict development of the breeding and bring numerous losses for production.The mechanism of sex premature is very complex and the real reason of that is unknown. While the usual reason for it is due to intrinsic and extrinsic factors. Most scholars emphatically studied and analyzed the relations between extrinsic factors such as temperature, water quality, water depth, density, nutrition and sex premature. We researched mainly on relations between intrinsic factors especially neuroendocrine mechanism and sex premature by three ways.1. Sinus glands of the crab were observed under light and electric microscope. Under electric microscope,we found the mount of granules type II in sex premature crabs is less than that of the matured. In addition, the granules type VII in the precocious were not found in the matured . While there were no evident difference between them under light microscope.2. In biochemical properties, we discovered that total concentration and the pH of tissue including ovary, optic ganglion and hemolymph in sex premature crabs are lower than those of the matured. We also found differences in molecular weight isoelectic point and proteomic. All that will lay the foundations of studying the mechanism.3. The total RNA was isolated from eyestalks and used RT-PCR technology to gain partial sequence of GIH. The pGEM-Teasy vector was used to connect the sequence and than transfer E.coli JM109.'We selected seven positive clones through several methods.
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