Proteomics analysis of differentially expressed proteins in schistosomula and adult worms of Schistosoma japonicum.

Schistosoma japonicum has a complex lifecycle and exhibits dramatic changes in its biology and morphology at different developmental stages. The schistosomulum and adult worm are two stages of this complex lifecycle and differentially expressed proteins in these two stages should be important for survival, development, and reproduction of the parasites. In this study, soluble and hydrophobic proteins were extracted from eggs, cercariae, schistosomula (8d and 19d), and male and female adult worms (42d) of Schistosoma japonicum, and separated by two-dimensional (2D) gel electrophoresis. A total of 1376±52, 928±61, 1465±41, 1230±30, 904±34, and 1080±26 soluble proteins and 1437±44, 845±53, 986±22, 1145±35, 1066±39, and 1123±45 hydrophobic proteins were separated from eggs, cercariae, schistosomula (8d and 19d), and male and female adult worms (42d), respectively. There were 65±14, 27±7, 37±17 and 48±9 soluble protein spots only present in schistosomula (8d and/or 19d) and adult schistosomes (male and/or female). We successfully identified 22 spots from schistosomula and 11 spots from adult schistosomes by mass spectrometry. Quantitative real-time RT-PCR was used to examine six differentially expressed proteins at the transcription level. These proteins only found in schistosomula or adults stage by the proteomics analysis were highly expressed in the corresponding stage at mRNA level. Bioinformatics analysis showed that the differentially expressed proteins from schistosomula were mainly involved in cellular metabolic processes, stress response and developmental process. Differentially expressed proteins from adult schistosomes were involved with gene expression and protein metabolism processes. The results of this study might provide new insights to stimulate further exploration of the mechanism of growth and development in schistosomes and help identify candidate molecules for developing new vaccines or drugs.