ABSTRACT
The aim of this study was to determine the differences in phototaxis between Oncomelania hupensis (O .h .) hupensis and O .h .robertsoni as well as four related geographic strains of male and female snails and Schistosoma japonicum-infected and-uninfected snails .Field collection of O . hupensis was performed in S . j aponicum-endemic areas of Xingzi and Yushan counties in Jiangxi Province ,China ,as well as Tianquan and Pengshan counties in Sichuan Province ,China .Infected and uninfected snails were screened using the cercariae escaping method ,with artificial separation of male and female snails . The experiment was carried out in an in-house constructed dark phototaxis experiment box using white light as the main source of light at the most suitable light intensity .Under a light intensity of 1 500 Lux for 30 minutes ,all of the snails from the experimental group showed obvious phototaxis .The statistical analysis showed no significant difference in the phototaxis index between male and female snails ,and there was also no significant difference in the phototaxis index between different geograph-ical strains of the same subspecies of snails .A significant difference in phototaxis was observed between the two subspecies during the 30-minute experimental period :O .h .hupensis displayed a higher phototaxis index than that of O .h .robertsoni , whereas S .japonicum-infected snails showed a lower phototaxis index than that of uninfected snails .A difference in phototaxis was found between different subspecies of O .hupensis and within the same subspecies .All uninfected snails displayed the same phototaxis index .When snails were infected with S .japonicum ,phototaxis reduced .
ABSTRACT
To explore the structure and function of thioredoxin glutathione reductase (TGR) from Schistosoma j aponi-cum ,the homologous model of TGR in Schistosoma j aponicum was constructed by Swiss-Pdbviewer based on sequence and structure alignment .The potential substrates binding sites of TGR were analyzed and these sites of various TGRs were also as-sessed .Our results showed that the homologous model of Schistosoma japonicum TGR based on Schistosoma mansoni TGR structure was proved to be reasonable by PROCHECK program .Analysis of binding sites showed that NADPH and GDS bind-ing sites were conservative sites and GSH binding site was a specific site for parasite .Our data suggested that inhibitors which work in NADPH and GDS binding sites of other various TGRs may also interact with TGR form Schistosoma j aponicum .GSH binding region might be one of the potential targets for design of specific inhibitors of parasite TGRs .In addition ,C-terminal of TGR plays an important role in electron transfer and may participate in the binding of the substrate .Thus compound inhibiting swing of C-terminal could effectively restrain Schistosoma j aponicum TGR activity .
ABSTRACT
To observe the dynamic changes of splenocyte proliferation ,subsets and apoptosis in mice immunized with re-combinantBifidobacteriumbifidum(pGEX-Sj26GST)ofSchistosomajaponicum,themiceweresubcutaneously(SCgroup) and intranasally (IN group) immunized ,respectively .Four mice from each group were sacrificed in every 2 wk during 0-20 wk after immunization .Splenocyte proliferation was investigated by MTT colorimetric assay ,subsets of CD+4 and CD+8 T cells and apoptosis of splenocytes by FACsort flow cytometry .In SC group ,unstimulated and stimulated with S jAWA ,the level of splenocyte proliferation significantly increased at 4-20 wk after vaccination and increased markedly at 4-18 wk stimulated with ConA ,both of which peaked at 8 wk;in IN group ,the proliferation level of splenocyte cultured with SjAWA and ConA signif-icantly increased during the 4-18 wk ,2-10 wk and 14-18 wk ,2-8 wk and 12-18 wk ,respectively ,and all reached the maximum at the 4 wk after immunization (P＜0 .01 or P＜0 .05) .CD+4 subsets increased obviously during 2-14 wk ,2 wk and 6-16 wk re-spectively ,and reached the peak at 8 wk (P＜0 .01 or P＜0 .05) in both group ,while CD8+ subsets rose lightly during 2-20 wk in both group ,and reached the maximum at 8 wk (SC group) and 6 wk respectively (P>0 .05) .Whether unstimulated or stimulated with ConA ,the level of splenocyte apoptosis of which remarkably increased at 2-4 wk and 2-6 wk separately in SC group ,and both peaked at 2 wk (P＜0 .01 or P＜0 .05 );in IN group ,the level of splenocyte apoptosis all increased at 4 wk and reached the maximum at the same time .In summary ,by inducing the proliferation of splenocytes ,increasing CD4 + T cells and decreasing splenocyte apoptosis ,the rBb (pGEX-Sj26GST ) vaccine plays a critical role in the protective immune response .