Effect of NaCl stimulation on the survival rate of freeze-dried cells and intracellular phosphofructokinase in Lactobacillus
NaCl刺激对乳杆菌冻干存活率及胞内磷酸果糖激酶的影响

NaCl stimulation affects the activity of phosphofructokinase (PFK) and survival rate of freeze-dried Lactobacillus bulgaricus. In the late logarithmic phase, adding 2% (W/V) NaCl to the growth medium markedly increased the survival rate of freeze-dried L. bulgaricus. Meanwhile, the activity of PFK in L. bulgaricus after NaCl stimulation was determined by reversed phase high performance liquid chromatography (RP-HPLC). The results showed that PFK activity was increased significantly by NaCl stimulation. In addition, a semi-quantitative RT-PCR method was applied to detect the PFK gene expression in different condition. The results indicated that the PFK gene expression was increased before freeze-drying and almost unchanged after freeze-drying. NaCl stimulation could enhance the survival rate of freeze-dried cells, and PFK might affect the survival of Lactobacillus bulgaricus.