The ability of Salmonella to enter mammalian cells is affected by bacterial growth state.

Abstract

We have examined the effect of different growth conditions on the ability of Salmonella to interact with Madin-Darby canine kidney cells. Two growth conditions that affect the expression of Salmonella adherence and invasiveness have been identified. First, bacteria lose their invasiveness in the stationary phase of growth. Second, bacteria growing in oxygen-limited growth conditions are induced for adherence and invasiveness, whereas those growing aerobically are relatively nonadherent and noninvasive. Salmonella from cultures aerated with gas mixtures containing 0% or 1% oxygen were 6-to 70-fold more adherent and invasive than those from cultures aerated with a gas mixture containing 20% oxygen.The Salmonella typhimurium oxrA gene that is required for the anaerobic induction of many proteins is n1 involved in the regulation of Salmonella invasiveness. We speculate that oxygen limitation might be an environmental cue that triggers the expression of Salmonella invasiveness within the intestinal lumen and other tissues.

Peptidoglycan structure of Salmonella typhimurium growing within cultured mammalian cells

“…The S. typhimurium peptidoglycan structure was shown consistently to be similar to that described for Escherichia coli (Pisabarro et al, 1985;Glauner et al, 1988;Gally and Cooper, 1993). However, in our study we used the highly virulent strain S. typhimurium SL1344, and specific growth conditions, such as non-shaking static growth, to render bacteria competent to infect cultured mammalian cells (Lee and Falkow, 1990). Therefore, an initial study was performed to analyse by HPLC the muropeptide composition of SL1344 grown overnight in LB medium (Lennox, 1995) under nonshaking conditions.…”

“…Bacteria were grown overnight in LB medium (Lennox, 1955), at 37ЊC, in static non-shaking conditions (OD 550 = 1.0) when required to infect cultured epithelial cells (Lee and Falkow, 1990). Bacteria were also grown in LB medium, at 37ЊC under shaking conditions (200 r.p.m.…”

Biogenesis of Salmonella typhimurium-containing vacuoles in epithelial cells involves interactions with the early endocytic pathway

“…It is particularly well documented that microtubules, which are essential for transport from early to late endosomes, are disrupted by incubation at low temperatures (Matteoni and Kreis, 1989;Gruenberg et al, 1989;D'Arrigo et al, 1997). As the expression of invasion loci in Salmonella, and consequently the invasion process itself, is known to be affected by physiological conditions (Ernst et al, 1990;Lee and Falkow, 1990;Behlau and Miller, 1993;Kusters et al, 1993;Schiemann, 1995), we examined whether ef®cient invasion could be obtained in 5 min by measuring bacterial invasion at various points on the growth curve. We found that S. typhimurium invasion in HeLa cells was most ef®cient when bacteria were grown to late log phase and that bacteria could invade cells ef®ciently within 5 min.…”

“…Previous studies have indicated that bacterial invasion is affected by growth phase, although, in most cases, investigators have used S. typhimurium grown to stationary phase and have incubated bacteria with cells for a minimum of 15 min, but usually considerably longer (Lee and Falkow, 1990;Behlau and Miller, 1993;Mills and Finlay, 1994;Garcia-del Portillo and Finlay, 1995;Burns-Keliher et al, 1997;Fu and Galan, 1998). Other investigators have synchronized invasion either by centrifuging Salmonella onto cell monolayers or by combining centrifugation with a 48C incubation step to enhance bacterial adhesion further.…”

Inflammatory Bowel Disease Susceptibility Gene C1ORF106 Regulates Intestinal Epithelial Permeability

“…The highly virulent S. Typhimurium strain SL1344 was grown by previously established methods (6). A single inoculum of bacteria was grown in Lysogeny broth under aerated (shaking) conditions at 37°C for 8 h. Cultures at late log phase (OD600 of 0.45-0.65) were collected, washed, and resuspended in sterile PBS at a concentration of 5 3 10 9 CFUs/ml.…”