Substrate utilization by Campylobacter jejuni and Campylobacter coli

Abstract

An attempt was made to elucidate in Campylobacter spp. some of the physiologic characteristics that are reflected in the kinetics of CO2 formation from four '4C-labeled substrates. Campylobacterjejuni and C. coli were grown in a biphasic medium, and highly motile spiral cells were harvested at 12 h. Of the media evaluated for use in the metabolic tests, minimal essential medium without glutamine, diluted with an equal volume of potassium sodium phosphate buffer (pH 7.2), provided the greatest stability and least competition with the substrates to be tested. The cells were incubated with 0.02 M glutamate, glutamine, a-ketoglutarate, or formate, or with concentrations of these substrates ranging from 0.0032 to 0.125 M. All four substrates were metabolized very rapidly by both species. A feature of many of these reactions, particularly obvious with a-ketoglutarate, was an immediate burst of CO2 production followed by CO2 evolution at a more moderate rate. These diphasic kinetics of substrate utilization were not seen in comparable experiments with Escherichia coli grown and tested under identical conditions. With C. jejuni, C02 production from formate proceeded rapidly for the entire period of incubation. The rate of metabolism of glutamate, glutamine, and aketoglutarate by both species was greatly enhanced by increased substrate concentration. The approach to the study of the metabolism of campylobacters here described may be useful in detecting subtle changes in the physiology of cells as they are maintained past their logarithmic growth phase.

The pattern and kinetics of substrate metabolism of Campylobacter jejuni and Campylobacter coli

“…Although the utilization of formate, L L-lactate, cysteine, glutamine, a-ketoglutarate, succinate, fumarate and aspartic acid and serine has been investigated by several studies (Alexander 1957;Kiggins and Plastridge 1958;Zemjanis and Hoyt 1960;Smibert 1963;Hoffman 1979;Veron et al 1981;Elharrif and Megraud 1986;Karmali et al 1986;Westfall et al 1986), the kinetic data of these substrates had not been determined. In the present study, kinetic data of individual substrate including affinity constant was obtained.…”

“…This lack of information impeded the full elucidation of survival, transmission and the pathogenicity of Campylobacter. Previous studies on Campylobacter metabolism (Alexander 1957; Kiggins and Plastridge 1958;Zemjanis and Hoyt 1960;Smibert 1963;Hoffman 1979;Veron et al 1981;Elharrif and Megraud 1986;Karmali et al 1986;Westfall et al 1986;Mendz et al 1997) were, mostly, based on investigation of substrate utilization in growth media and rarely derived kinetics data of these substrates studied. It was found that citric acid cycle (CAC) intermediates, but not carbohydrates, can serve as excellent energy source for Campylobacter (Alexander 1957).…”

Analyses of energy metabolism and stress defence provide insights into Campylobacter concisus growth and pathogenicity

“…As most strains of C. jejuni cannot utilise sugars [24,26,27], C. jejuni mainly relies on amino acids and C4-dicarboxylates as a primary energy source [28]. C. jejuni is known to preferentially use the amino acids aspartate, serine, glutamate, asparagine and proline [29][30][31][32], as well as the C4-dicarboxylates fumarate, succinate and malate [30]. Use of amino acids and C4-dicarboxylates for energy metabolism are interconnected as amino acids can be converted into C4-dicarboxylates that can enter the TCA cycle or be used in the electron transport chain for energy metabolism.…”

Effects of thymol and diphenyliodonium chloride against Campylobacter spp. during pure and mixed culture in vitro

“…However, concentrations of these electron acceptors typically are low within gut environments and it is unclear how much growth may be supported by this process. Campylobacter can conserve energy via substrate-level phosphorylation during catabolism of the amino acids aspartate, alanine, glutamate, glutamine, methionine and serine (Westfall et al 1986;Mohammed et al 2004;Velayudhan et al 2004). Intermediate and end products of amino acid catabolism by Campylobacter include acetate, formate, fumarate, lactate, pyruvate and succinate thus indicating the involvement of mixed acid fermentation and reductive metabolism of the tricarboxcylic acid pathway (Laanbroek et al 1978a;Mendz and Hazell 1996).…”