Objective The aim of this study was to characterize the basic molecular and biochemical parameters for a cyclophilin protein in Cryptosporidium parvum called CpCyP1.Methods CpCyP1 expression patterns during the parasite life cycle were evaluated using qRT-PCR with total RNA isolated from different developmental stages of C.parvum.Native CpCyP1 protein in sporozoites was detected using western blot.The localization of CpCyP1 was performed using the immunofluorescence assay,with an affinity-purified rabbit polyclonal antibody against a synthetic peptide.The peptidyl-prolyl cis-trans isomerase(PPIase)activity of His-tagged recombinant CpCyP1 was evaluated using absorbance colorimetry,and the effect of cyclosporin A(CsA)on the activity of CpCyP1 was determined.Results CpCyP1 was expressed in all parasite developmental stages,whereas CpCyP1 was present mainly in the cytosol of sporozoites,meronts,and gamonts.CpCyP1 displayed Michaelis-Menten kinetics towards N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide for its PPIase activity(Km=456.4 μmol/L;Vmax=1.981 U).CsA inhibited PPIase activity,showing lower micromolar inhibitory activity and binding affinity(Kd=5.122 μmol/L;IC50=1.004 μmol/L).Conclusions These results imply that CpCyP1 in the parasite may be the target for the previously reported anti-cryptosporidial efficacy of CsA and suggest that C.parvum cyclophilins could be evaluated as candidate drug targets.

To introduce the application of Stata software to heterogeneity test in meta-analysis.A data set was set up according to the example in the study,and the corresponding commands of the methods in Stata 9 software were applied to test the example.The methods used were Q-test and Ⅰ2statistic attached to the fixed effect model forest plot,H statistic and Galbraith plot.The existence of the heterogeneity among studies could he detected hy Q-test and H statistic and the degree of the heterogeneity could be detected by,Ⅰ2 statistic.The outliers which were the sources of the heterogeneity could be spotted from the Galbraith plot.Heterogeneity test in Meta-analysis can be completed by the four methods in Stata software simply and quickly.H and Ⅰ2 statistics are more robust,and the outliers of the heterogeneity can be clearly seen in the Galbraith plot among the four methods.