Effect of tatD gene deletion of Listeria monocytogenes on virulence and gut microflora in mice
[Objective]This study,with an investigation of the effects of tatD gene deletion in Listeria monocytogenes on virulence and gut microbiota in mice(Mus musculus),is aimed to provide reference for the role of tatD in the interaction between L.monocytogenes and the host,as well as for the study of attenuated vaccines.[Method]First,mice were orally infected with LM10403s,LM 10403s △tatD and LM10403sC△tatD strains using the Bliss method to determine the strain's median lethal dose(LD50)for mice before immunoprotective effect of LM10403s△tatD was observed in mice immunized with 1.00×105 CFU orally.Then,forty 6-week-old female mice were randomly and equally divided into PBS(ck),LM10403s,LM10403s△tatD,and LM10403sC△tatD groups,with those in the ck group gavaged with 200 μL of sterile PBS and the ones in the experimental group gavaged with 200 μL of bacterial solution containing 1.00 × 106 CFU,respectively.Next,after 24 h of gavage,the mice in each group were dissected and killed,with intestinal contents collected before Illumina Hiseq sequencing technology was used to determine the sequences of the microbial 16S rRNA V3-V4 regions of the cecum samples from each group so that a comparative analysis was conducted of the structure of microbial communities,diversity,and signaling pathway enrichment.[Result]The LD50 of LM10403s△tatD was 8.11×107 CFU,which was less virulent than that of the parental strain.Oral immunization of mice with LM 10403s△tatD provided 80％protection against L.monocytogenes parental strain infection.Chaol and Observed species indices showed that the difference between ck and LM 10403s △tatD group was not significant,but LM 10403s and LM10403sC△tatD group were significantly lower compared to ck group(P＜0.05).At the phylum level,the relative abundance of the Firmicutes in LM 10403s△tatD group was higher than that in LM10403s and LM 10403sC△tatD group,and at the genus level,the relative abundance of the genus,Lactobacillus in LM 10403s△tatD group was higher than that in LM 10403s and LM 10403sC△tatD group functional prediction analysis showed that LM 10403s group in signaling pathways including cellular processes,environmental information processing,and metabolism was more enriched than the LM10403s△tatD group.[Conclusion]The deletion of tatD gene reduced the virulence of L.monocytogenes and had animmuno protective effects while infection of the tatD gene deletion mutant strain in mice reduced the effect on intestinal flora dysbiosis and increased the beneficial bacteria.[Ch,6 fig.1 tab.21 ref.]
万方数据
维普
