OBJECTIVETo set up a rapid, efficient, reliable and accurate method for separation of Bacteriodes forsythus proteins.

METHODSBacteroides forsythus ATCC43037 cells were harvested by centrifugation, washed in Tris buffer to remove excess medium, and lysed by sonication. The sonicated lysis proteins were extracted step by step with ReadyPrep Sequential Extraction Kit (Bio-Rad). The supernatant of B. forsythus proteins were used for two-dimensional gel electrophoresis. The first dimension IEF (isoelectric focusing) was run with Immobiline DryStrip (pH 3-10) and the second dimension SDS-PAGE was run with Excelgel SDS, gradient 8-18 precast gel and buffer strips. The separated proteins were stained with Coomassie Brilliant Blue and silver staining kit (Plusone Silver Staining Kit, Protein, Pharmacia Biotech).

RESULTS1. The protein spots were clear when sample cups were used in the middle of IPG strip during IEF. 2. B. forsythus proteins were separated clearly by horizontal two-dimensional electrophoresis and most of B. forsythus whole-cell proteins were acidic proteins (P13-7).

CONCLUSIONHorizontal two-dimension electrophoresis is a useful method for separating B. forsythus proteins.