title: Reducing activity, glucose metabolism and acid tolerance response of Bacillus cereus grown at various pH and oxydo-reduction potential levels.
abstract: Bacillus cereus is a major foodborne bacterial pathogen able to survive a large number of physical-chemical stresses. B. cereus encounters different pH and redox potential (Eh7) levels during its passage through the gastrointestinal tract. Analysis of the combined influence of pH and redox stresses on B. cereus F4430/73 physiology found that B. cereus F4430/73 growth at pH 7.0 at 37 °C had strong reducing capacities, with a total change of 315 mV from an initial redox value of +214 ± 17 mV. The combination of low Eh7 and low pH led to a drastic reduction of growth parameters compared to oxidative Eh7 and neutral pH. Metabolic analysis showed that low pH significantly modifies glucose fermentative metabolism, with changes including decreased production of acid metabolite (acetate, lactate, formate) and increased production of 2,3-butanediol. Low Eh7 slightly enhanced the acid-tolerance response of B. cereus whereas low pH pre-adaptation led to thermal stress cross-protection. These results highlight new mechanisms that bring fresh insight into B. cereus pH and redox stress adaptations.
authors.affiliation: Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France; INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Le Lay
authors.affiliation: Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France.
authors.forename: Halim
authors.initials: H
authors.lastname: Bahloul
authors.affiliation: INRA, UR1115 Unité Plantes et Systèmes de Culture Horticoles, 84000 Avignon, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Sérino
authors.affiliation: Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France; INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Jobin
authors.affiliation: Université d'Avignon et des Pays de Vaucluse, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France; INRA, UMR408 Sécurité et Qualité des Produits d'Origine Végétale, 84000 Avignon, France. Electronic address: philippe.schmitt@univ-avignon.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Schmitt
mesh_terms: D000143:Acids / Q000378:metabolism*; D001409:Bacillus cereus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction
chemical_list: D000143:Acids; D003470:Culture Media; D005947:Glucose
keywords: 2,3-Butanediol; Acid stress; Bacillus cereus; Glucose metabolism; Redox potential; Thermal stress