LuxS-based quorum sensing does not affect the ability of Salmonella enterica serovar Typhimurium to express the SPI-1 type 3 secretion system, induce membrane ruffles, or invade epithelial cells.
Bacterial species can communicate by producing and sensing small autoinducer molecules by a process known as quorum sensing. Salmonella enterica produces autoinducer 2 (AI-2) via the luxS synthase gene, which is used by some bacterial pathogens to coordinate virulence gene expression with population density. We investigated whether the luxS gene might affect the ability of Salmonella enterica serovar Typhimurium to invade epithelial cells. No differences were found between the wild-type strain of S. Typhimurium, SL1344, and its isogenic luxS mutant with respect to the number and morphology of the membrane ruffles induced or their ability to invade epithelial cells. The dynamics of the ruffling process were also similar in the wild-type strain (SL1344) and the luxS mutant. Furthermore, comparing the Salmonella pathogenicity island 1 (SPI-1) type 3 secretion profiles of wild-type SL1344 and the luxS mutant by Western blotting and measuring the expression of a single-copy green fluorescent protein fusion to the prgH (an essential SPI-1 gene) promoter indicated that SPI-1 expression and activity are similar in the wild-type SL1344 and luxS mutant. Genetic deletion of luxS did not alter the virulence of S. Typhimurium in the mouse model, and therefore, it appears that luxS does not play a significant role in regulating invasion of Salmonella in vitro or in vivo.
Perrett
Charlotte A
CA
Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol, United Kingdom.
Karavolos
Michail H
MH
Humphrey
Suzanne
S
Mastroeni
Pietro
P
Martinez-Argudo
Isabel
I
Spencer
Hannah
H
Bulmer
David
D
Winzer
Klaus
K
McGhie
Emma
E
Koronakis
Vassilis
V
Williams
Paul
P
Khan
C M Anjam
CM
Jepson
Mark A
MA
D000199:Actins / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D004285:Dogs; D004847:Epithelial Cells / Q000382:microbiology*; D005260:Female; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008858:Microscopy, Phase-Contrast; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology*; D019779:Salmonella enterica / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria