Comparative proteomic identification of the hemocyte response to cold stress in white shrimp, Litopenaeus vannamei.

To understand molecular responses of crustacean hemocytes to cold stress, flow cytometer analysis and two-dimensional electrophoresis proteomic approach were used to investigate altered proteins in hemocytes of Litopenaeus vannamei during cold stress treatment. Through flow cytometer analysis, 13°C for 24h post-cold stress was selected as the suitable temperature and condition for cold stress treatment. MALDI-TOF/TOF MS analysis revealed that 6 forms of 6 proteins were significantly up-regulated, including three enzymes (cystathionase, glyceraldehyde 3-phosphate dehydrogenase and glyoxalase 1) and one immune-related protein (oncoprotein nm23), whereas 24 forms of 3 proteins were significantly down-regulated in the treated shrimp (hemocyanin, hemocyte transglutaminase and transketolase). There were 20 spots identified as hemocyanin meaning that it may play important roles in environmental regulation in shrimp. Real-time fluorescence quantitative PCR confirmed that the levels of transcription of the hemocyanin, partial mRNA for hemocyanin, cystathionase, glyoxalase 1 and oncoprotein nm23 genes were found to relate well with that of their translation products after cold stress treated, while only the levels of hemocyte transglutaminase transcripts were not corresponded with that of their translation products. Further investigation of these data may lead to better understanding of the molecular responses of crustacean hemocytes to cold stress.