Proteome analysis of Cryptosporidium parvum and C. hominis using two-dimentional electrophoresis, image analysis and tandem mass spectrometry

Until recently, Cryptosporidium was thought to be a single species genus. Molecular studies now showthat there are at least 10 valid species of this parasite. Among them, two morphologically identical species, C.hominis and C. parvum are the most pathogenic identified to date and share 97% of identical genomes.Post-genomic analyses is therefore necessary to explore further the genetic variations among them. During this study, a comparative proteomic approach was applied to analyze the differential expression of sporozoite proteins in both C. hominis and C. parvum. Using 2-DE gels with different pH ranges (3-10 and 4- 7) and automated three dimensional (3D) image analyses, a total of 20 protein spots were shown to be differentiallyexpressed between the two species. Mass spectrometry analyses of these spots identified one hypothetical protein, however, identification of the remaining spots was unsuccessful. Further characterization of this hypothetical protein along with all differentially expressed proteins could provide crucial information in understanding the differential biology of Cryptosporidium spp.