lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.

The genus Salmonella includes many pathogens of great medical and veterinary importance. Bacteria belonging to this genus are very closely related to those belonging to the genus Escherichia. lacZYA operon and lacI are present in Escherichia coli, but not in Salmonella enterica. It has been proposed...

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Main Authors: Sandeepa M Eswarappa, Guruswamy Karnam, Arvindhan G Nagarajan, Sangeeta Chakraborty, Dipshikha Chakravortty
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2009-06-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC2686271?pdf=render
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author Sandeepa M Eswarappa
Guruswamy Karnam
Arvindhan G Nagarajan
Sangeeta Chakraborty
Dipshikha Chakravortty
author_facet Sandeepa M Eswarappa
Guruswamy Karnam
Arvindhan G Nagarajan
Sangeeta Chakraborty
Dipshikha Chakravortty
author_sort Sandeepa M Eswarappa
collection DOAJ
description The genus Salmonella includes many pathogens of great medical and veterinary importance. Bacteria belonging to this genus are very closely related to those belonging to the genus Escherichia. lacZYA operon and lacI are present in Escherichia coli, but not in Salmonella enterica. It has been proposed that Salmonella has lost lacZYA operon and lacI during evolution. In this study, we have investigated the physiological and evolutionary significance of the absence of lacI in Salmonella enterica. Using murine model of typhoid fever, we show that the expression of LacI causes a remarkable reduction in the virulence of Salmonella enterica. LacI also suppresses the ability of Salmonella enterica to proliferate inside murine macrophages. Microarray analysis revealed that LacI interferes with the expression of virulence genes of Salmonella pathogenicity island 2. This effect was confirmed by RT-PCR and Western blot analysis. Interestingly, we found that SBG0326 of Salmonella bongori is homologous to lacI of Escherichia coli. Salmonella bongori is the only other species of the genus Salmonella and it lacks the virulence genes of Salmonella pathogenicity island 2. Overall, our results demonstrate that LacI is an antivirulence factor of Salmonella enterica and suggest that absence of lacI has facilitated the acquisition of virulence genes of Salmonella pathogenicity island 2 in Salmonella enterica making it a successful systemic pathogen.
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spelling doaj.art-9fb0839b97bc43ce93bceba35f160d272022-12-22T01:57:39ZengPublic Library of Science (PLoS)PLoS ONE1932-62032009-06-0146e578910.1371/journal.pone.0005789lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.Sandeepa M EswarappaGuruswamy KarnamArvindhan G NagarajanSangeeta ChakrabortyDipshikha ChakravorttyThe genus Salmonella includes many pathogens of great medical and veterinary importance. Bacteria belonging to this genus are very closely related to those belonging to the genus Escherichia. lacZYA operon and lacI are present in Escherichia coli, but not in Salmonella enterica. It has been proposed that Salmonella has lost lacZYA operon and lacI during evolution. In this study, we have investigated the physiological and evolutionary significance of the absence of lacI in Salmonella enterica. Using murine model of typhoid fever, we show that the expression of LacI causes a remarkable reduction in the virulence of Salmonella enterica. LacI also suppresses the ability of Salmonella enterica to proliferate inside murine macrophages. Microarray analysis revealed that LacI interferes with the expression of virulence genes of Salmonella pathogenicity island 2. This effect was confirmed by RT-PCR and Western blot analysis. Interestingly, we found that SBG0326 of Salmonella bongori is homologous to lacI of Escherichia coli. Salmonella bongori is the only other species of the genus Salmonella and it lacks the virulence genes of Salmonella pathogenicity island 2. Overall, our results demonstrate that LacI is an antivirulence factor of Salmonella enterica and suggest that absence of lacI has facilitated the acquisition of virulence genes of Salmonella pathogenicity island 2 in Salmonella enterica making it a successful systemic pathogen.http://europepmc.org/articles/PMC2686271?pdf=render
spellingShingle Sandeepa M Eswarappa
Guruswamy Karnam
Arvindhan G Nagarajan
Sangeeta Chakraborty
Dipshikha Chakravortty
lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
PLoS ONE
title lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
title_full lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
title_fullStr lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
title_full_unstemmed lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
title_short lac repressor is an antivirulence factor of Salmonella enterica: its role in the evolution of virulence in Salmonella.
title_sort lac repressor is an antivirulence factor of salmonella enterica its role in the evolution of virulence in salmonella
url http://europepmc.org/articles/PMC2686271?pdf=render
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