渗透压对细菌的影响

在等渗溶液中,微生物正常生长繁殖;在高渗溶液中,细胞失水收缩,而水分为微生物生理生化反应所必需,失水会抑制其生长繁殖.根据不同盐质量分数下细菌的繁殖情况,可以判断渗透压对细菌的影响.用含不同质量分数NaCl的牛肉膏蛋白胨培养基培养细菌来观察渗透压对细菌的影响,选用的菌种为金黄色葡萄球菌,大肠杆菌,枯草芽孢杆菌.大肠杆菌耐高渗透压的能力较差,在质量分数为3%以下的NaCl溶液中能正常生长,在5%的NaCl溶液中受到抑制;枯草芽孢杆菌和金黄色葡萄球菌有较强的耐盐能力,枯草芽孢杆菌在5%的NaCl溶液中能正常生长,在10%的NaCl溶液中受到抑制,而金黄色葡萄球菌在10%的NaCl溶液中仍能正常生长,在高于10%的NaCl溶液中生长受到抑制.

Osmosis for the Influence of Bacteria

To study in isotonic solution,the normal growth and reproduction of microorganisms;in hypertonic solution,the cell dehydration shrinkage,and water for the microorganisms necessary for physiological and biochemical reactions,water loss will inhibit the growth and reproduction1].According to the propagation of bacteria under different salt conditions,can determine the impact of osmotic pressure on the bacteria.NaCl containing different concentrations of beef extract peptone medium for bacteria to observe the impact of osmotic pressure on the bacteria,selected strains Staphylococcus aureus,Escherichia coli,Bacillus subtilis.The ability of E.coli resistant to high osmotic pressure less,at under 3% of NaCl and could grow under 5% NaCl that inhibited;Bacillus subtilis and Staphylococcus aureus have a stronger salt tolerance,Bacillus subtilis,under 5% NaCl and could grow under 10% NaCl was inhibited,while Staphylococcus aureus in 10% NaCl normal despite the growth of above 10% NaCl in growth was inhibited under.