鱼源无乳链球菌N-乙酰氨基葡萄糖苷酶NalA的鉴定及生物学功能分析  

Identification and biological function of N-acetylglucosaminidase NalA in the piscine Streptococcus agalactiae

作　　者：董雨豪 徐艳楠 聂蒙 曹青[1] 姬姝婷 刘广锦[1] 刘永杰[1] DONG Yuhao;XU Yannan;NIE Meng;CAO Qing;JI Shuting;LIU Guangjin;LIU Yongjie(College of Veterinary Medicine,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学动物医学院,江苏南京210095

出　　处：《畜牧与兽医》2021年第12期65-70,共6页Animal Husbandry & Veterinary Medicine

基　　金：江苏省自然科学基金项目(BK20171376);中央高校基本科研业务费项目(KYGD202103);江苏高校优势学科建设工程项目(PAPD)。

摘　　要：为了探究N-乙酰氨基葡萄糖苷酶在无乳链球菌(Streptococcus agalactiae)中的生物学功能,本试验通过生物信息学技术从鱼源无乳链球菌GD201008-001基因组中预测到一个可能的N-乙酰氨基葡萄糖苷酶编码基因A964;097(命名为nalA),利用同源重组技术构建该基因缺失株ΔnalA及互补株CΔnalA,并对野生株、缺失株及互补株的细菌形态、生长能力、自溶能力以及对斑马鱼的致病力进行检测。结果显示,与野生株相比,ΔnalA的细菌链增长约10倍;对数生长期的生长速率明显下降;在第24 h时,自溶能力降低69.36%;对斑马鱼的半数致死量(50%lethal dose, LD_(50))为5.87×10^(2)CFU,比野生株升高约4倍。互补株CΔnalA的各项指标均恢复至野生株水平。本研究结果为进一步探究N-乙酰氨基葡萄糖苷酶NalA在无乳链球菌致病过程中的作用机制奠定基础。To investigate the biological function of N-acetylglucosaminidase in Streptococcus agalactiae, in this study, a possible N-acetylglucosaminidase gene A964;097(named nalA) was predicted from the genome of Streptococcus agalactiae GD201008-001 based on bioinformatics, the gene deletion strain ΔnalA and its complementary strain CΔnalA were constructed by homologous recombination, and the bacterial morphology, growth ability, autolysis ability and pathogenicity of the three strains to zebrafish were detected. The results showed that, compared with the wild strain, the chain of ΔnalA exhibited about 10-fold increase, its growth rate in the logarithmic growth period decreased markedly, and at 24 h, its autolysis ability reduced by 69.36%. The median lethal dose(LD_(50)) of ΔnalA to zebrafish was 5.87 × 10^(2)CFU, about 4 times higher than that of the wild strain. All the above phenotypes in the CΔnalA strain were restored to the level of the wild strain. This study laid a foundation for further exploring the role of NalA in the pathogenesis of S.agalactis.

关 键 词：无乳链球菌 N-乙酰氨基葡萄糖苷酶 结构预测 nalA 基因缺失 生物学功能 

分 类 号：S852.61[农业科学—基础兽医学]