The effect of a high hydrostatic pressure treatment on the Gram-positive Listeria monocytogenes strain Scott A and the Gram-negative Salmonella typhimurium strain Mutton (ATCC13 311) has been determined in stationary ...
详细信息
The effect of a high hydrostatic pressure treatment on the Gram-positive Listeria monocytogenes strain Scott A and the Gram-negative Salmonella typhimurium strain Mutton (ATCC13 311) has been determined in stationary phase cell suspensions. Pressure treatments were done at room temperature for 10 min in sodium citrate (pH 5.6) and sodium phosphate (pH 7.0) suspension buffers. Increasing pressure treatments resulted in an exponential decrease of cell counts. Salmonella typhimurium suspended at low pH was more sensitive to pressure treatments. Progressive morphological changes were evident with the pressure increase. Cell lysis only appeared with the highest pressure treatments. Cell volume was not affected by pressure treatment. A progressive decrease of delta pH (pH(in) - pH(out)), intracellular potassium and ATP contents was demonstrated with the pressure increase. A parallel lowering of membrane potentials was measured.
Outer membrane vesicles were reconstituted from phospholipids, lipopolysaccharide, and outer membrane proteins isolated from Salmonella typhimurium . The vesicles appeared to be permeable to sucrose and other small ol...
详细信息
Outer membrane vesicles were reconstituted from phospholipids, lipopolysaccharide, and outer membrane proteins isolated from Salmonella typhimurium . The vesicles appeared to be permeable to sucrose and other small oligosaccharides only when membrane proteins were added to the reconstitution system. The size of saccharides that could pass through the vesicle membranes was found to be close to the size of saccharides that penetrate through the intact outer membrane of S. typhimurium .
暂无评论