RESUMO
Objective: To screen for the potential specific membrane protein from the protein database built by our Lab and to clone the encoding sequence of a potential immunoprotective protein according to the screening result, so as to search for new vaccine candidate or drug targets for Schistosomiasis control. Methods: The related data were retrieved using the key words "Schistosoma japonicum" and "membrane or tegument" from the NCBI database to construct local database of membrane protein of S. japonicum. The specific membrane proteins were screened by multi-alignment with the protein sequences from our local database of Schistosoma mansoni, Homo sapiens, Rattus norvegicus and Mus musculus. Meanwhile, the character and function of the predicted membrane protein were analyzed with public software in the website CBS. The specific primer for the sequence of the predicted protein with potential immuno-protective function were designed and synthetized; the coding sequence was then amplified from the adult worm of S. japonicum by PCIZ and was cloned into rokaryotic expression vector pGEX-4T-1. Results: A total of 153 predicted membrane protein of S. japonicum were retrieved and 28 potentially specific for S. japonicum were screened out. The coding sequence of the predicted protein, with a relative molecular weight of about 15 000, was successfully amplified from the adult worm of S. japonicum and was temporarily named gene sj15; the recombinant plasmid pGEX-4T-1-sjl5 was also successfully constructed. Conclusion: Many specific membrane proteins of S. japonicum have been successfully screened out. The predicted sjl5 gene (announced as AY223457 in GenBank) has been successfully cloned, proving the existence of sj15 gene in adult worm of S. japonicum. The prokaryotic expression vector pGEX-4T-1 for sj15 has also been successfully constructed, providing a foundation for further study of sj15 function.
RESUMO
Objective To delineate the m orp hology and ecology of a new human schistosome species. Methods (1)Adult schistosomes were obtained from infected mice and rabbi ts with cercariae shedding from snails which were infected with miracidia devel oping from the eggs in feces of acute schistosomiasis patients. (2)T he rabbits were dissected during 60-100 d infection period of cecariae, and thei r bladders were taken out for detecting eggs in the urine. (3)Schistosome eggs i n the feces of patients were examined with microscopy. Results (1)There were two types of male worms: one was with an average o f size 8.76 mm long and 0 43 mm wide while the other with an average size of 2 41 mm long and 0 091 mm wide and with undeveloped gynecophoral canal which ap peared in front of ventral sucker (2)There were two types of female worms: one was with an average of size 10 73 mm long and 0 74 mm wide while the other wi th an average of size 3 43 mm long and 0 12 mm wide and was fine, semitranspar ent and tape like with undeveloped ovary and vitellaria. Less than 10 eggs or none were found in t he uterus. (3)There were a lot of degenerated and black eggs in the feces of 2 p atients. (4) Schistosome eggs were detected in the urine and miracidia were hatc hed out from 8 out of 16 infected rabbits.(5) Others: 8 worms were detected in 1 mouse out of 12 dissected mice for evaluation of infectious water with sentry m ice in spite of that no Oncomelania snails were found in the area. Cercariae stayed on water surface in lying position like a c omma. The eggs returned forwardly a fter growing behind the ovary in female worm. ConclusionAccording to the primary investigation in morphology an d ecology, the new schistosome obtained is distinct from the 6 well defined ty p es of human schistosome. It is considered that a new schistosome species should be foun d and temporarily nominated as Schistosoma nanjingi( S.n.)
