API-ZYM系统分析动物双歧杆菌胞外酶活性

Analysis of extracellular enzyme activity of Bifidobacterium animalis by API-ZYM system

中文关键词:  动物双歧杆菌  API-ZYM系统  胞外酶  表达量  失活率

英文关键词:Bifidobacterium animalis  API-ZYM system  extracellular enzyme  expressions  inactivation rate

中文摘要:

      目的 利用API-ZYM系统分析动物双歧杆菌胞外酶活性。方法 采用培养法分离菌株, 经提取DNA后采用16 S rRNA测序, 采用高分辨率熔解曲线分析技术(high resolution melting, HRM)方法以及SNP(single nucleotide polymorphism)位点组合鉴定菌株; 利用API-ZYM系统分析分离菌株的胞外酶活性共性和差异性, 研究产业化前后菌株酶活性的变化。结果 分离出动物双歧杆菌Bb-12、乳双歧杆菌Bi-07和HN019。能检测到14种胞外酶, 有4种胞外酶未检出。酶谱的分泌共性及稳定性基本保持一致, 其中糖苷酶类活性最高; HN019和Bb-12的酶谱具有高相似性, Bi07更显现出胞外酶特异性; 工业化前后糖苷酶类仍然保持高活性, 而水解酶类失活程度高。结论 糖苷酶的高表达量普遍存在于动物双歧杆菌中; 酶谱差异性可作为划分菌株特征的重要鉴定技术手段; 工业化前后酶谱的变化为商业化益生菌体外预筛选评价提供理论参考。

英文摘要:

      Objective To analyze the extracellular enzyme activities of Bifidobacterium animalis by API-ZYM system. Methods The strains were isolated by cultivation, confirmed through 16 S rRNA sequencing, HRM(high resolution melting) and SNPs(single nucleotide polymorphism). API-ZYM system was used to compare the similarities and differences in exoenzyme activities among those isolated strains. The variations in strains’ enzyme activities were investigated before and after industrialization. Results Strains such as Bifidobacterium animalis Bb-12, Bifidobacterium lactis Bi-01 and HN019 were isolated. Totally 14 types of exoenzymes were detected, and 4 types were undetectable. The secretory commonness and stability of the exoenzyme activities were basically the same, among which the glycosidase activity was the highest. Besides, great similarities between HN019 and Bb-12 were shown in exoenzymes’ activities while Bi07 displayed more specialization in secreting enzymes. The glycosidase activity remains constant before and after industrialization, however, hydrolase had a higher degree of deactivation after industrialization. Conclusion The high level of glycosidase is ubiquitously expressed in Bifidobacterium animalis. The differences in exoenzyme activities could be a significant landmark of strains’ characterization and identification. The variations in exoenzyme activities before and after industrialization provide great theoretical reference values to the evaluation of in vitro pre-screen industrialized probiotics.