| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1991: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1990: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
We performed two investigations during the term of this project.
1. The cytochemical changes of the Golgi stacks occurring concomitantly with cell differentiation were examined in ameloblasts of developing rat molar tooth germs using osmium impregnation and cytochemistry with NADPase, TPPase, and ACPase. NADPase, TPPase, and ACPase activities were already present in the Golgi stacks of the inner enamel epithelial cells and the presecretory ameloblast : NADPase activity existed in the medial Golgi cisternae, TPPase activity in the trans Golgi cisternae, and ACPase activity in almost all cisternae and strongly in the trans-most cisterna of the Golgi stack. At these stage, however, osmium deposits after impregnation were not observed in the cisterna of the Golgi stacks. Osmiophilic cisternae in the Golgi stacks were apparent for the first time at the stage when the Golgi apparatus developed and migrated to the region dist4-l to the nucleus with the progression of cell differentiation. Thes
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e findings indicate that the cis subcompartment of the Golgi apparatus was incomplete in the inner enamel epithelial cells and the presecretory ameloblast. It is suggested that the cis subcompartment of the Golgi stack may be completed only in the last stage of the compartmentalized Golgi organization during differentiation of the ameloblast.
2. The functional modulation of the Golgi stacks during cell differentiation was examined in the ameloblasts of developing rat molar tooth germs, using HRPlabeled lectins ; Con A GS-I, SBA, UEA-I, WGA and PNA. The Golgi stacks of the inner enamel epithelial cells and presecretory ameloblasts were stained with five lectins except for PNA. In some cases, the reaction products for the lectins were observed in most cisternae of the Golgi stacks. In the secretory ameloblasts, however, the reaction products were found in definite cisternae of the Golgi stack, so that discrete staining pattern of the Golgi stack was found for each lectin. These findings indicate that various glycosyltransferase may coexist in most cisternae of the Golgi stack of the inner enamel epithelial cells and presecretory ameloblasts. Moreover, the staining patterns of the lectins in secretory ameloblasts suggest that these cells secrete proteins with N-linked and 0-linked oligosaccharide chains. Less
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