肠毒性大肠杆菌eutR和eutB基因敲除对其生长繁殖和生物被膜生成量的影响

Effects of eutR and eutB Gene Knockout on Growth and Reproduction and Biofilm Formation in Enterotoxic Escherichia coli

乙醇胺在肠道内大量存在且能够被肠道微生物利用,是一种潜在的信号分子。为了研究乙醇胺对肠毒性大肠杆菌(ETEC)致病性的影响,本研究首先利用Red同源重组技术对ETEC识别和利用乙醇胺的关键基因:eutR和eutB分别进行敲除,随后模拟肠内缺氧条件,利用乙醇胺对3株ETEC(野生型和eutR、eutB基因敲除株)进行干预,探讨了乙醇胺对ETEC生长繁殖和生物被膜形成的影响。结果发现:Red技术可对ETEC菌株eutR和eutB基因进行有效敲除;此外,肠道乙醇胺浓度(4 mmol/L)虽然不能改变3株ETEC在LB培养基中的生长繁殖速度,但能够显著增加野生型ETEC生物被膜的生成量(P<0.05),而对eutR和eutB基因敲除株没有此种增强效果(P>0.05)。结果提示,宿主肠道环境中乙醇胺浓度可能调控ETEC生物被膜形成,而在这一过程中ETEC识别和利用乙醇胺的关键基因eutR和eutB可能起到关键作用。

Ethanolamine is a potential signaling molecule,which is abundant in intestinal tract and can be utilized by intestinal microorganisms. In order to study the influence of ethanolamine on the pathogenicity of enterotoxic Escherichia coli(ETEC),firstly Red homologous recombination technology was used to knockout the eutR and eutB genes,which were key genes of the ethanolamine identify and utilization in ETEC,respectively.Subsequently,in order to investigate the effects of ETEC on growth and reproduction and biofilm formation,three ETEC strains(wild-type and eutR and eutB gene knockout strains)were treated with ethanolamine under simulated enteral hypoxia conditions. The results showed that Red technique could effectively eliminate eutR and eutB genes in ETEC. In addition,intestinal ethanolamine concentration(4 mmol/L)significantly increased the biofilms production of wild-type ETEC(P<0.05),however,the growth and propagation rate of ETEC in LB medium could not be changed. There was no such enhancement effect for eutR and eutB gene knockout strains(P>0.05). The results suggest that ETEC biofilm formation may be regulated by ethanolamine in the host intestinal ethanolamine environment,and the key genes eutR and eutB may play a key role in this process.