OBJECTIVE: To explore the protein profile and identify developmentally regulated proteins of the promastigotes and axenic amastigotes with comparative proteomics technique. METHODS: The total proteins of promastigotes and axenic amastigotes of Leishmania donovani SC6 strain were separated by two-dimensional electrophoresis (2-DE) in a broad pH range (3-10), and the gel was stained with Coomassie blue. The images were analyzed by PDQuest 1.0 software, and the major developmentally regulated proteins were identified by electrospray mass spectrometry. RESULTS: Approximately 700 protein spots were revealed in equivalent proteins of the promastigotes and axenic amastigotes separated by 2-DE, among which more than 90% protein spots showed equivalent quantity and distribution, with 6 proteins up-regulated and 3 proteins down-regulated in axenic amastigotes compared with promastigotes. Five of the 6 up-regulated proteins were with known function, respectively ascribed as Rieske iron-sulfur protein precursor, alpha-tubulin, peroxidoxin 1, dihydrolipoamide acetyltransferase precursor, and mannose-1-phosphate guanylyltransferase. Two of the 3 down-regulated proteins were identified as heat shock protein 70 and beta-tubulin. The functions of the developmentally regulated proteins were related to the carbohydrate/energy metabolism, stress response, or formation of cell membrane/cytoskeleton. CONCLUSION: The findings demonstrate the differences in protein expression profiles between promastigotes and amastigotes.
OBJECTIVE: To explore the protein profile and identify developmentally regulated proteins of the promastigotes and axenic amastigotes with comparative proteomics technique. METHODS: The total proteins of promastigotes and axenic amastigotes of Leishmania donovani SC6 strain were separated by two-dimensional electrophoresis (2-DE) in a broad pH range (3-10), and the gel was stained with Coomassie blue. The images were analyzed by PDQuest 1.0 software, and the major developmentally regulated proteins were identified by electrospray mass spectrometry. RESULTS: Approximately 700 protein spots were revealed in equivalent proteins of the promastigotes and axenic amastigotes separated by 2-DE, among which more than 90% protein spots showed equivalent quantity and distribution, with 6 proteins up-regulated and 3 proteins down-regulated in axenic amastigotes compared with promastigotes. Five of the 6 up-regulated proteins were with known function, respectively ascribed as Rieske iron-sulfur protein precursor, alpha-tubulin, peroxidoxin 1, dihydrolipoamide acetyltransferase precursor, and mannose-1-phosphate guanylyltransferase. Two of the 3 down-regulated proteins were identified as heat shock protein 70 and beta-tubulin. The functions of the developmentally regulated proteins were related to the carbohydrate/energy metabolism, stress response, or formation of cell membrane/cytoskeleton. CONCLUSION: The findings demonstrate the differences in protein expression profiles between promastigotes and amastigotes.