Analysis of protein expression profiles of Halobacillus dabanensis D-8T under optimal and high salinity conditions

Two-dimensional (2-D) gel electrophoresis was employed to display the expression profiles of proteins of Halobacillus dabanensis D-8(T) under 1%, 10%, and 20% salinities. Approximately 700 protein spots could be detected in the 2-D gels by Imagemastertrade mark 2D Platinum software. The molecular masses of the majority of intracellular proteins were distributed in the range of 17.5 kDa-66 kDa and isoelectric points of 4.0-5.9. In total 133 protein spots were observed with a changed expression level under different salinity conditions. Sixty-two protein spots showed upregulation and 26 new protein spots were found under high salinity conditions, while 25 protein spots were downregulated and 20 spots disappeared. Twenty-seven proteins with a markedly changed expression in hypersaline environments were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and MASCOT. A changed expression pattern was observed for proteins related to energy-producing pathways, stress regulators, and proteins involved in the survival of strain D-8(T) under high salt challenges. Many proteins play necessary roles in the adaptation to high salt or as a general stress protein, and some proteins are salt-stressed specific proteins that improve the capability of salt-tolerance of strain D-8(T) growth under extremely hypersaline condition.