Construction of Attenuated Listeria monocytogenes Strain EGDe-△sigB and Preliminary Identification of Biological Activity of sigB
CHEN Guo-wei
LIU Wu-kang
DING Cheng-chao
XIE Man-man
GUO Liang
DONG Qing-li
LIU Qing
Abstract：Listeria monocytogenes is a foodbome pathogen infectious to both humans and animals.L.monocytogenes can cross the human intestinal barrier,placental barrier,and blood-brain barrier,thereby causing gastroenteritis,meningitis,miscarriage,and other diseases.Sigma B factor,encoded by the gene sigB,is an important regulatory factor for the envir onmental stress response in many Gram-positive bacteria,and directly and indirectly controls the expression of important virulence genes,such as prfA and inlA.The sigB gene of L.monocytogenes strain EGDe was knocked out by homologous recombination,and the resulting ddetion swain (EGDe-AsigB) was used to study the effect of sigB deletion on growth,expression of 13 virulence genes (including inlA,inlB,andprfA),and invasion of Caco-2 intestinal epithelial cells.The results showed that the growth rate of the EGDe-△sigB strain was equivalent to that of the wild-type EGDe strain.Deletion of sigB caused a significant reduction in the expression levels of inlA and inlB,but a significant (four-to five-fold) increase in the expression levels of the virulence genes actA and plcA,demonstrating that sigB has a relatively large influence on the expression of some virulence genes in L.monocytogenes.Furthermore,invasion assays indicated that deletion of sigB caused a decline in the ability of L.monocytogenes strain EDGe to invade Caco-2 cells.
Keywords：Listeria monocytogenes (Lm)sigBbiological propertiescell invasion
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 102-108 )