Virulence regulation of cel-EIIB protein mediated PTS system in Streptococcus agalactiae in Nile tilapia
Virulence regulation of cel-EIIB protein mediated PTS system in Streptococcus agalactiae in Nile tilapia
复制标题
cel-EIIB蛋白介导的尼罗罗非鱼无乳链球菌PTS系统毒力调控
DOI：
10.1111/jfd.12907
复制
发表时间：
2019
影响因子：
2.5
通讯作者：
Li An-Xing
中科院分区：
文献类型：
--
作者：
Xu Jun;Xie Yun-Dan;Liu Ling;Guo Song;Su You-Lu;Li An-Xing
无乳链球菌（Streptococcus agalactiae）是罗非鱼的主要致病菌，每年给全球水产业造成重大经济损失。阐明cel‐EIIB蛋白介导的磷酸转移酶系统（PTS）在S.无乳，通过同源重组实现了强毒株THN 0901中的cel-EIIB基因缺失。在含10 mg/ml纤维二糖的LB培养基中，△cel‐ EIIB菌株的纤维二糖利用率显著低于S.a.THN0901菌株（p< 0.05）。△cel‐ EIIB菌株在BHI培养基中培养时生物膜形成能力也显著降低（p< 0.05）。在较低的感染剂量下，△cel‐ EIIB菌株对罗非鱼的累计死亡率显著降低（20%），其中S.a.THN0901菌株和△cel‐EIIB：：i菌株的累计死亡率分别为53.33%和50%。罗非鱼模型的竞争实验表明，△cel‐ EIIB菌株的入侵和定殖能力显著弱于S.a.THN0901菌株（p< 0.05）。与△cel‐EIIB：：i株相比，△cel‐ EIIB株csrS、csrR、rgfA、rgfC、bgrRandbgrS的mRNA表达显著下调（p<0. 05）。总之，cel‐EIIB蛋白介导的cel‐PTS不仅有助于生物膜形成和毒力调节，而且在S的入侵和定殖中起重要作用。无乳。
Streptococcus agalactiaeis a major pathogen of tilapia causing significant economic losses for the global aquatic industry yearly. To elucidate the role of cel‐EIIB protein‐mediated phosphotransferase systems (PTS) in the virulence regulation ofS. agalactiae,cel‐EIIBgene deletion in a virulent strain THN0901 was achieved by homologous recombination. The cellobiose utilization of △cel‐EIIBstrain was significantly decreased relative toS.a.THN0901 strain incubating in LB with 10 mg/ml cellobiose (p< 0.05). The biofilm formation ability of △cel‐EIIBstrain was also significantly decreased when cultured in BHI medium (p< 0.05). Under a lower infection dose, the accumulative mortality of tilapia caused by △cel‐EIIBstrain was dramatically decreased (20%), of whichS.a.THN0901 strain and △cel‐EIIB::istrain were 53.33% and 50%, respectively. The competition experience using tilapia model indicated the invasion and colonization ability of △cel‐EIIBstrain was significantly weaker than that ofS.a.THN0901 strain (p< 0.05). Compared to △cel‐EIIB::istrain, the mRNA expression ofcsrS,csrR,rgfA, rgfC, bgrRandbgrSwas significantly downregulated in △cel‐EIIBstrain (p< 0.05). In conclusion, cel‐EIIB protein‐mediated cel‐PTS not only contributes to biofilm formation and virulence regulation, but also plays an important role in the invasion and colonization ofS. agalactiae.