| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1998: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1997: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
(1997)
1 : Bovine sperm receptor was shown to be involved In the carbohydrate moieties of zona glyciproteins by an in vitro competition assay. 2 : Competition assay also revealed that bovine sperm mainly bind to a high-mannnose type carbohydrate chain, Man_5GlcNAc_2 which is major neutral N-linked chain found in bovine zona proteins. It has been reported that mouse sperm bind to beta-galactosyl residues at the non-reducing ends of O-linked chain of ZP3 protein, while porcine sperm to beta-galactosyl residues at the non-reducing ends of N-linked chains of ZPB.Our results on the bovine sperm receptors contribute much to the elucidation of the mechanism of species-specific sperm-egg binding. 3 : In order to obtain O-linked chains, the zona proteins were treated with alkali under various conditions. The activities, however, could not be measured, since N-linked chains were also cleaved partly together with O-linked chains under any conditions.
(1998)
1 : The receptor active carbohydrate chain was shown to be present in ZPB protein. It is unclear whether the active chain is present in ZPA, since heteropolymers were shown to be contaminated in ZPA obtained by HPLC, We are trying to purify ZPA.2 : Large scale preparation of ZPB for determination of the localization of receptor active carbohydrate chain in ZPB is also In progress. 3 : It was shown that the receptor active chain, Man_5GlcNAc_2, inhibits bovine in vitro fertilization (IVF) and its derivatives Man_3GlcNAc_2, ManG1cNAc_2, and alpha-methylmannoside also weakly inhibit IVF, indicating the essential role of mannose residue(s) at the non-reducing ends in bovine IVF.4 : Treatment of the unfertilized eggs with sialidase reduced the number of binding sperm to the eggs to about 50%, suggesting that sialic acids also play a role in the bovine sperm binding to the eggs.
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