6株羊源乳酸杆菌电转化条件的优化

Optimication of Electrotransformation Conditions of Six Lactobacilli Strains

选取质粒pLEM415-egfp电转化源于陕北白绒山羊瘤胃的乳酸杆菌,研究不同生长时期及电场强度对6株羊源乳酸杆菌电转化效率的影响,并优化其转化条件。在37℃培养条件下,培养6株羊源乳酸杆菌,当D600 nm达到0.4、0.6、0.8、1.0和1.2时,离心收集菌体,制备感受态细胞;在电阻200Ω、电容25 uF条件下,分别采用1.5、2.0和2.5 kV 3种电场强度电击转化感受态细胞。结果表明,羊源植物乳酸杆菌(Lactobacillus plantarum)、干酪乳酸杆菌(Lactobacillus casei)、罗伊乳酸杆菌(Lactobacillus reuteri)、短乳杆菌(Lactobacillus brevis)、棒状乳酸杆菌(Lactobacillus coryniformis)和弯曲乳酸杆菌(Lactobacillus curvatus)获得最高转化效率的D600 nm和电场强度分别为0.8、1.2、1.0、0.6、0.8、0.4和1.5、1.5、1.5、1.5、1.5、2.0 kV。羊源乳酸杆菌最佳转化条件的确立,为后续乳酸杆菌转基因工程菌的构建及其应用奠定了基础。

This study was aimed to establish the optimal electrotransformation conditions of six Lactobacilli strains （L.plantarum, L.casei, L.reuteri, L.brevis, L.coryniformis and L.curvatus） which isolated from Shanbei White cashmere goats＇ rumen, plasmid pLEM415-egfp was electrotransformed into competent cell of six Lactobacilli on different growth phase （D600 nm=0.4, 0.6, 0.8, 1.0 and 1.2）, and the electrotransformation efficiency was investigated under resistance 200 Ω, capacitance 25 uF and different electric field strength （1.5, 2.0 and 2.5 kV）. Results showed that the optimal D600 nm and electric field strength to obtain the maximum transformation efficiency for L.plantarum, L.casei, L.reuteri, L.brevis, L.coryniformis and L.curvatus were 0.8, 1.2, 1.0, 0.6, 0.8, 0.4 and 1.5, 1.5, 1.5, 1.5, 1.5, 2.0 kV, respectively. The establishment of optimal electrotransformation conditions for six Lactobacilli strains provided the foundation for further construction and application of transgenic Lactobacillus.