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目的探讨适合提取德氏乳杆菌保加利亚亚种质粒的细菌培养基。方法配制含不同比例MRS的营养肉汤混合培养基,进行德氏乳杆菌保加利亚亚种的培养,通过生长曲线测定、细菌形态观察,菌体内天然质粒抽提质量等来确定适于该菌质粒抽提的最佳混合培养基。结果单纯营养肉汤培养基不适合德氏乳杆菌保加利亚亚种的增殖,在含20%、40%、60%及80%MRS的营养肉汤混合培养基中该菌的生长曲线与在MRS中的基本一致,但细菌数略低;形态学检测表明含MRS的营养肉汤培养基培养对德氏乳杆菌保加利亚亚种的形态无影响,质粒抽提结果表明,本研究所配制的几种含不同比例MRS的营养肉汤混合培养基中,含20%MRS的营养肉汤混合培养基最适合该菌质粒的抽提,提取的质粒浓度高,质量好。结论本实验制备的混合培养基中,含20%MRS的营养肉汤混合培养基能保证德氏乳杆菌保加利亚亚种的正常增殖,而且可能由于产生较少的胞外多糖,使溶菌酶更易水解该菌细胞壁肽聚糖,最适于该菌质粒的抽提。
Objective To investigate the bacterial culture medium suitable for the extraction of Lactobacillus delbrueckii subsp. Bulgaricus. Methods Nutrient broth mixed medium with different ratios of MRS was prepared to culture Lactobacillus delbrueckii subsp. Bulgaricus. The growth curve, morphological observation of bacteria, The best mixed medium. Results The simple nutrient broth was not suitable for the proliferation of Lactobacillus delbrueckii subsp. Bulgaricus. The growth curve of the strain in the mixed broth containing 20%, 40%, 60% and 80% MRS was similar to that of MRS The results of morphological examination showed that the culture medium containing MRS had no effect on the morphology of Lactobacillus delbrueckii subsp. Bulgaricus. The results of plasmid extraction showed that several kinds of Different proportions of MRS nutrient broth mixed medium, 20% MRS nutrient broth best medium for the extraction of the plasmid, the extraction of plasmid concentration, good quality. CONCLUSION: The mixed media containing 20% MRS in the mixed culture medium prepared in this experiment can ensure the normal proliferation of Lactobacillus delbrueckii subsp. Bulgaricus, and the lysozyme may be more easily hydrolyzed by less exopolysaccharide The bacteria cell wall peptidoglycan, the most suitable for the bacterial plasmid extraction.