| Summary: | 碩士 === 國立陽明大學 === 寄生蟲學研究所 === 88 === Schistosomiasis, a chronic granulomatous immune disease, is one of the most important human parasitic infections. Africa is the largest endemic area of schistosomiases. Among the 75 endemic countries in the world, there are 40 countries prevalent with more than two species of schistosomes. It has been reported that several species of schistosomes may coexist in the same human host. Moreover, experimental hybridization of human and animal strains of schistosomes prevalent in Africa has been studied extensively. However, only little information in the hybridization of Schistosoma japonicum with the other species/strains. The antibodies of the host cause formation of granuloma, an important pathogenic finding in schistosomiasis. Since species-specific glycoprotein has been demonstrated in S. mansoni and S. japonicum, it is generally considered that glycoproteins are the major antigens on the eggs of schistosomes. In the present study, hybridizations were carried out between S. mansoni and S. japonicum. Although most of the eggs in the F1 generation were immature, dead, or calcified, the morphology of the rare mature ones was demonstrated to be similar to the mother species. By analysis of the structure of the glycoproteins on the egg shell, S. mansoni eggs was shown to have a xylosylated 6-fucosylated trimannosyl core whereas S. japonicum eggs with a xylosylated 3-,6-difucisylated trimannosyl core. In addition, the glycoprotein structure of the F1 eggs was similar to that of the mother species. Although the male stimulation may not be necessary to the egg production in S. mansoni, the same phenomenon was not observed in S. japonicum. These findings indicate that offspring from the interspecific pairings between S. mansoni and S. japonicum may be due to parthenogenesis. Moreover, it also explains the similarity in the morphology and glycoprotein structure in the eggs.
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