Use of Bombyx mori Mutants to Study on Insect Biochemistry

威尔斯实验室从家蚕中肠中分离出叶黄素结合蛋白(40 KDa)。富士还从Y+^I家蚕中肠分离并鉴定了类胡萝卜素结合蛋白(600 KDa)。该蛋白与血淋巴中的CBP蛋白在免疫学上的相似性和与CBP相同的生化性质上是一致的。彝家蚕中肠含有黄色蛋白，而Y+^I家蚕则不含。色素为类胡萝卜素。但该蛋白不与抗CBP抗体反应。因此，它是一个新的类胡萝卜素结合蛋白，而不是CBP。构建了Y+^I家蚕中肠基因文库。用抗CBP抗体克隆了CBP基因的编码区，获得了多个克隆。对两个克隆进行了核苷酸序列分析，但它们与家蚕中肠和中丝腺的类胡萝卜素结合蛋白(CBP)不完全相同。免疫金标记法显示CBP定位于粗面内质网和与光滑内质网相关的小泡中，类胡萝卜素通过胞吐作用以类胡萝卜素结合的CBP复合体的形式从中肠分泌到血淋巴中，从血淋巴中以复合体的形式进入丝腺中部，最后转运为丝胶，然后排出丝胶颗粒。从家蚕血淋巴中纯化出一种脂转移颗粒(LTP)。LTP有3个脱辅基蛋白(占颗粒质量的79%)：apo LTP-I，apoLTP=IInd apoLTP=III，MR=350,000，85,000和60,000。LTP的脂类为磷脂(54%)、甘油单酯(8.3%)、二酰甘油(17%)、游离脂肪酸(14.3%)、三酰甘油(5.9%)和碳氢化合物(0.4%)，该蛋白能催化多种脂类在不同脂粒之间的转移。

Wells lab isolated lutein bound protein (40kDa) from the midgut of silkworm. Fuji also isolated and characterized carotinoid binding proitein (600kDa) from the midgut of the Y+^I silkworm. This protein is identical with CBP in hemolymph on the bisis of immunological similarity and the same biochemical properties as to CBP.The midgut of the YI silkworm contained a yellow colored protein, but did not in the Y+^I silkworm. The color pigment was carotinoid. But the protein did not react with anti-CBP antibody. Hence it is a new carotinoid binding protein other than CBP.cDNA library from the midgut of the Y+^I silkworm was constracted. cDNA encoding CBP has been cloned by using anti-CBP antibody and several clones were obtained. Two clones were analyzed nucleotide sequence, but they were not identical to CBP.Immunocytochemical analysis of carotinoid binding protein (CBP) in the midgut and middle silkgland of silkworm, Bombyx mori. Immunogold technique showed that CBP was located in rough ER,and in the small vesicle associated with smooth ER.Carotinoid was secreated into hemolymph from midgut as carotinoid bound CBP complex by exocytosis, incorporated into the middle part of silkgland from hemolymph as the complex and finally tansferrd to sericin prior to excretion of sericine particles.A lipid transfer particles (LTP) has been purified from the hemolymph of Bombyx mori. the LTP has three apoproteins (79% of particles mass) apo LTP-I,apoLTP=IInd apoLTP=III,Mr=350,000,85,000and 60,000. The lipid of LTP is phosphalipid (54%), monoacylgicerol (8.3%), diaacylglycerol (17%), free fatty acid (14.3%), triacylglycerol (5.9%) and hydrocarbon (0.4%).This protein is able to catalyze the transfer of a number of lipids among different lipid particle.