Osmolarity and growth phase overlap in regulation of Salmonella typhi adherence to and invasion of human intestinal cells

Tartera, Carmen; Metcalf, Eleanor S.

doi:10.1128/iai.61.7.3084-3089.1993

Cited by 125 publications

(81 citation statements)

References 30 publications

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“…In contrast, high osmolarity is one condition that induces the optimal expression of invasion genes, including hilA, invF and sipC in S. typhimurium (Bajaj et al, 1996;Chen et al, 1996) and cpxA, invG and prgH in S. typhi (Tartera and Metcalf, 1993;Leclerc et al, 1998). This regulatory control is mediated by the HilA transcriptional activator in S. typhimurium (Bajaj et al, 1996).…”

Section: Resultsmentioning

confidence: 99%

“…Both Mg 2þ and Ca 2þ are extracellular signals governing the activity of the PhoP-PhoQ system (Garcia Vé scovi et al, 1996). Interestingly, osmolarity, growth phase, oxygen and pH also modulate the expression of S. typhi invasion genes (Tartera and Metcalf, 1993;Leclerc et al, 1998). Salmonella species are motile by means of peritrichous flagella. The filament of each flagellum generally consists of around 20 000 subunits of flagellin.…”

Section: Introductionmentioning

confidence: 99%

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The RcsB–RcsC regulatory system of Salmonella typhi differentially modulates the expression of invasion proteins, flagellin and Vi antigen in response to osmolarity

Arricau

Hermant

Waxin

et al. 1998

Molecular Microbiology

170

181

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SummaryEntry into intestinal epithelial cells is an essential feature in the pathogenicity of Salmonella typhi, which causes typhoid fever in humans. This process requires intact motility and secretion of the invasion-promoting Sip proteins, which are targets of the type III secretion machinery encoded by the inv, spa and prg loci. During our investigations into the entry of S. typhi into cultured epithelial cells, we observed that the secretion of Sip proteins and flagellin was impaired in Vi-expressing strains. We report here that the production of Sip proteins, flagellin and Vi antigen is differentially modulated by the RcsB-RcsC regulatory system and osmolarity. This regulation occurs at both transcriptional and post-translational levels. Under low-osmolarity conditions, the transcription of iagA, invF and sipB genes is negatively controlled by the RcsB regulator, which probably acts in association with the viaB locusencoded TviA protein. The cell surface-associated Vi polysaccharide, which was maximally produced under these growth conditions, prevented the secretion of Sip proteins and flagellin. As the NaCl concentration in the growth medium was increased, transcription of iagA, invF and sipB was found to be markedly increased, whereas transcription of genes involved in Vi antigen biosynthesis was greatly reduced. The expression of iagA, whose product is involved in invF and sipB transcription, occurred selectively during the exponential growth phase and was maximal in the presence of 300 mM NaCl. At this osmolarity, large amounts of Sips and flagellin were secreted in culture supernatants. As expected from these results, and given the essential role of Sip proteins and motility in entry, RcsB and osmolarity modulated the invasive capacity of S. typhi. Together, these findings might reflect the adaptive response of S. typhi to the environments encountered during the different stages of pathogenesis.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The RcsB–RcsC regulatory system of Salmonella typhi differentially modulates the expression of invasion proteins, flagellin and Vi antigen in response to osmolarity

Arricau

Hermant

Waxin

et al. 1998

Molecular Microbiology

170

181

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“…The cloning and mutagenesis of the LPS genes of A. sobria will be required to resolve the question of the role of LPS in A. sobria adhesion to HEp-2 cells. Environmental factors such as temperature, nutrient deprivation and growth phase are known to play a role in regulating the virulence of bacterial pathogens including A. hydrophila [3,18,19]. The stable rough and smooth variants of .4. sobria 3767 may have been selected in vivo in response to environmental conditions we were unable to reproduce in vitro.…”

Section: The Role Of Lps In Adhesion Of a Sobria 3767 To Hep-2 Cellsmentioning

confidence: 99%

Variable expression of O-antigen and the role of lipopolysaccharide as an adhesin inAeromonas sobria

Francki

Chang

1994

FEMS Microbiology Letters

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On initial isolation of Aeromonas sobria 3767 from a diarrhoeal stool specimen, two colony types were obtained: opaque (3767O) and translucent (3767T). Strain 3767O consistently produced lipopolysaccharide (LPS) core and O-antigen side chain, detectable by SDS-PAGE and by Western blotting with an O-antigen-specific monoclonal antibody. Strain 3767T produced LPS core but the amount of O-antigen was dependent on factors including growth medium and bacterial growth phase. Strain 3767T exhibited significantly lower levels of adhesion to HEp-2 cells than 3767O and this correlated with the level of LPS expression, with the greatest reduction (61%) at stationary phase when no LPS was detectable. The results implicate LPS as an adhesin for A. sobria 3767.

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“…I N THE ENVIRONMENT, SALMONELLA EXISTS IN THE STATIONARY phase and may be in the stationary phase when ingested (Tartera and Metcalf 1993). As Salmonella bacteria travel towards the distal regions of the intestinal tract, pH progressively decreases and SCFA concentrations increase from the proximal region of the ileum to the cecum (Cummings and others 1987).…”

Section: Discussionmentioning

confidence: 99%

“…Prior to the adherence assay, the medium overlying the HEp-2 cells was replaced with fresh prewarmed RPMI 1640 and incubated for 30 min at 37 °C in 5% CO 2 . In order to inoculate the HEp-2 cells with a similar quantity of bacteria from the different time points and the different SCFA concentrations, a modification of the methods described by Tartera and Metcalf (1993) was used. The S. typhimurium cultures were concentrated or diluted to an absorbance at 600 nm (A 600 ) of 0.4.…”

Section: Cell-association Assaymentioning

confidence: 99%

Short Chain Fatty Acids Alter HEp‐2 Cell Association and Invasion by Stationary Growth Phase Salmonella Typhimurium

Durant¹,

Lowry²,

Nisbet³

et al. 2000

Journal of Food Science

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We examined the ability of stationary phase Salmonella typhimurium to adhere and invade cultured HEp-2 cells after growth in broth supplemented with acetate, propionate, butyrate, or a mixture of the three short chain fatty acids (SCFA). At pH 6, all concentrations, except 25 and 50 mM butyrate, reduced cell-association of S. typhimurium when compared to controls, while at pH 7 only 100 mM concentrations of acetate and butyrate reduced cell-association significantly. Invasion percentages were greater for S. typhimurium grown at an initial pH of 6 with 25 mM acetate when compared to controls, SCFA mixture, and all other single SCFA concentration combinations. At pH 7, invasion was greater with either the SCFA mixture or 25 or 50 mM acetate than with control and all other single SCFA concentration combinations.

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Osmolarity and growth phase overlap in regulation of Salmonella typhi adherence to and invasion of human intestinal cells

Cited by 125 publications

References 30 publications

The RcsB–RcsC regulatory system of Salmonella typhi differentially modulates the expression of invasion proteins, flagellin and Vi antigen in response to osmolarity

The RcsB–RcsC regulatory system of Salmonella typhi differentially modulates the expression of invasion proteins, flagellin and Vi antigen in response to osmolarity

Variable expression of O-antigen and the role of lipopolysaccharide as an adhesin inAeromonas sobria

Short Chain Fatty Acids Alter HEp‐2 Cell Association and Invasion by Stationary Growth Phase Salmonella Typhimurium

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