Glucose uptake by Listeria monocytogenes Scott A and inhibition by pediocin JD

Abstract

Glucose uptake by Listeria monocytogenes Scott A was inhibited by the bacteriocin pediocin JD and by the protonophore carbonyl cyanide m-chlorophenyhydrazone. Experiments with monensin, nigericin, chlorhexidine diacetate, dinitrophenol, and gramicidin, however, showed that glucose uptake could occur in the absence of a proton motive force. L. monocytogenes cell extracts phosphorylated glucose when phosphoenolpyruvate (PEP) was present in the assay mixture, and whole cells incubated with 2-deoxyglucose accumulated 2-deoxyglucose-6-phosphate, indicating the presence of a PEP-dependent phosphotransferase system in this organism. Glucose phosphorylation also occurred when ATP was present, suggesting that a proton motive force-mediated glucose transport system may also be present. We conclude that L. monocytogenes Scott A accumulates glucose by phosphotransferase and proton motive force-mediated systems, both of which are sensitive to pediocin JD. Listeria monocytogenes is a facultative anaerobic pathogen that has been implicated in numerous food poisoning outbreaks and food product recalls (8). Despite significant interest in developing processes to control this organism, relatively little is known about the basic physiology of Listeria spp. (20). Although resting cells of L. monocytogenes Scott A at near

Bacteriocin inhibition of two glucose transport systems in Listeria monocytogenes

“…In addition to dissipation of PMF, bacteriocins are reported to deplete intracellular adenosine triphosphate (ATP), either through leakage or hydrolysis, and to cause efflux of intracellular inorganic phosphate (P i ) (Abee et al 1994a;Abee et al 1994b;Winkowski et al 1994;Chen and Montville 1995). Some bacteriocins also inhibit uptake and induce efflux of nutrients such as amino acids and sugars (van Belkum et al 1991;Venema et al 1993;Christensen and Hutkins 1994).…”

“…Glucose uptake assays were started by addition of [ 14 C]glucose (3·7 mCi mmol −1 ; Sigma Radiochemicals, St. Louis, MO, USA) to cell suspensions to give a final concentration of either 15 mmol l −1 (PMF-mediated transport) or 0·5 mmol l −1 (PEP-dependent PTS). Mixtures were incubated at room temperature and, at regular intervals, 1 ml samples of cell suspension were removed and centrifuged through silicon oil (12 000 g for 2 min) (Christensen and Hutkins 1994). Radioactivity was determined by liquid scintillation counting as described previously (Parker and Hutkins 1997).…”

Bacteriocins inhibit glucose PEP:PTS activity in Listeria monocytogenes by induced efflux of intracellular metabolites

“…It was reported that glucose PEP:PTS activity in four L. monocytogenes strains was inhibited by the bacteriocins nisin, pediocin JD and leuconocin S (Waite et al 1998). Inhibition of the PEP:PTS in L. monocytogenes Scott A by pediocin JD was also reported previously (Christensen and Hutkins 1994). In the presence of pediocin JD and exogenous PEP, phosphorylation of glucose by permeabilized L. monocytogenes Scott A cells decreased 86% (Christensen and Hutkins 1994).…”

“…Inhibition of the PEP:PTS in L. monocytogenes Scott A by pediocin JD was also reported previously (Christensen and Hutkins 1994). In the presence of pediocin JD and exogenous PEP, phosphorylation of glucose by permeabilized L. monocytogenes Scott A cells decreased 86% (Christensen and Hutkins 1994).…”

“…It was postulated that the observed increase in PTS activity in pep 5-sensitive cells may be due to pep 5induced dissipation of PMF (Kordel and Sahl 1986). However, stimulation of the PEP:PTS by the loss of PMF contradicts inhibition seen by researchers in this laboratory (Christensen and Hutkins 1994;Waite et al 1998).…”