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Background & Objective: The pattern of cell types in vertebrate embryos depend on the function of organizing centers, specialized cell groups that direct the fate of nearby cells through the secretion of inductive factors. Our previous studies showed that during early neural tube formation, the notochord is essential for the induction of ectoderm and for the subsequent differentiations of the neuroepithelium. It is well known that glycoconjugates are developmentally regulated expression on the surfaces of early embryonic cells and could therefore be involved in many critical morphogenetic and histogenetic events during embryonic development. Materials & Methods: In the present study, histochemical studies were carried out to detect the presence and distribution of terminal sugars during development of precursors of motor neurons within the developing spinal cord in balb/c mice. Embryos from day 9 to 14 of gestation were fixed and processed for lectin histochemical studies by using horseradish peroxidase labeled WFA with binding specificity for terminal N-acetylgalactosamine. Results: The first reaction was occurred weakly on the cells surface and extra cellular matrix just around the peripheral portion of floor plate on day 13 of gestation. It seems that these cells are developing premotor neurons, which will form the future motor neurons of the spinal cord. The reaction increased significantly and extended to the deep part of spinal floor plate by day 14. Conclusion: These data indicate that glycoconjugates containing N-acetylgalactosamine may play important roles in differentiation of the floor plate motor neuron and perhaps glia cells in final development of the ventral part of the spinal cord.

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Background&Objective: Carbohydrate chains link to glycoproteins and glycolipids of the cell surface particulary their terminal sugars have key roles in cellular activities of almost all biological systems. Distribution of these glycoconjugates in adult kidney has not received fair attention yet. The purpose of this study was to identify in situ location of galactose – N – acetyle galactoseamine moleucles on the surface of the adult rat kidney. Materials&Methods: After the resection of rat kidney and rotin fixation with regular lectin histochemical technique, MPA and PNA conjugated to horseradish peroxidase, lectins specific to indentify these terminal sugars in rat kidney. Results: Intense reaction of PNA to collective tubules, less intense and reaction with luminal surface of proximal tubules and MPA identified distinct cells among distal tubules as well as glomerules were observed. Conclusion: It seems that this specific sugars related to the cellulars function of this region of adult kidney and probably genetically is regulated during embryonic development.