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Articles by Kenichi Hatanaka
Total Records ( 3 ) for Kenichi Hatanaka
  Tomohisa Kato , Maria Carmelita Z. Kasuya and Kenichi Hatanaka
  The effect of fumonisin B1 which is an inhibitor of ceramide synthesis on saccharide elongation of dodecyl β-lactoside (Lac-C12), which is the analogue of lactosyl ceramide (LacCer), in mouse melanoma B16 cells and African green-monkey kidney (Vero) cells was examined. By adding fumonisin B1 in the culture medium used for glycosylation of Lac-C12, mouse melanoma B16 cells synthesized GM3-type analogue twice much as the absence of fumonisin B1, while the amount of endogenous GM3 remarkably decreased. The addition of fumonisin B1 to the culture medium of Vero cells also elicited 50% augmentation in the amount of glycosylated Lac-C12. For the enhanced production of oligosaccharide using cell function, fumonisin B1 acts effectively on cells which produce abundant endogenous glycolipid. The addition of fumonisin B1 resulted in an increase in production of glycosylated Lac-C12 with decreasing natural ceramide synthesis.
  Tomohisa Kato , Rie Mitsumori and Kenichi Hatanaka
  Artificial oligosaccharides were modified using recombinant Escherichia coli cells that overexpress sialidase. Based on the principle of the saccharide primer method by using bacterial cells overexpressing enzymes related to oligosaccharide modification. Problem statement: It is very hard to obtain oligosaccharides, because they have complex and diverse structures with different linkage patterns and monosaccharide components. Approach: It had been known that various oligosaccharides can be synthesized in mammalian cells from saccharide primers. We attempted to modify oligosaccharides by using bacterial cells overexpressing enzymes related to oligosaccharide modification instead of mammalian cells. Results: The glycosphingolipid-like derivative GM3 was absorbed by the cell and desialylated by the expressed sialidase and the desialylated product was then secreted into the medium. The GM3-type oligosaccharides were not detected from the cell fraction of recombinant E. coli cells that overexpress sialidase differently from recombinant E. coli carrying only vector DNA (pET-19b). Conclusion/Recommendations: E. coli as well as mammalian cells may be used as a biocatalyst for oligosaccharide modification and production of artificial functional oligosaccharides.
  Tomohisa Kato , Rie Mitsumori and Kenichi Hatanaka
  Problem statement: Mammalian cells were used for the production of oligosaccharides by saccharide primer method. However, because cells in culture are used, productivity of oligosaccharides is low. Approach: In saccharide primer method employing cells under culture, glycosylation was performed only by mixing the collected cells in reaction mixtures. Saccharide primer, 12-azidododecyl β-lactoside that mimics lactosylceramide (LacCer), was incubated with various mammalian cells under stirring or static conditions. The glycosylated primers were generated by adding and agitating cells in reaction mixtures like in the case where cells in culture were treated with saccharide primer. Results: In the case of African green-monkey kidney (Vero) cells, the amount of generated GM3-type oligosaccharide increased approximately five times by the reaction under agitating condition as compared with the reaction with cells in culture. GM3-type oligosaccharide was also synthesized by mouse melanoma B16 cells under both agitating or standing conditions. Moreover, the amount of GM3-type and GM1-type oligosaccharides produced by using African green-monkey kidney COS7 cells only by mixing the collected cells was greater than the general saccharide primer method. Conclusions/Recommendations: We demonstrated that the suspension mixture of the adhesive cells can be used as a catalyst for the synthesis of oligosaccharides in saccharide primer method. Moreover, suspended cells could produce more amount of oligosaccharides than normally cultured cells.
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