title: Role of the glutamate decarboxylase acid resistance system in the survival of Listeria monocytogenes LO28 in low pH foods.
abstract: The glutamate decarboxylase (GAD) acid resistance system of the foodborne pathogen Listeria monocytogenes plays a major role in its survival at low pH. It was found that survival of the wild-type strain. LO28, in acidified reconstituted skim milk, diluted to reduce free glutamate levels. improves in response to supplementation with monosodium glutamate. A mutant, in which the two listerial GAD homologs have been deleted (and in which there is no discernible GAD activity), did not respond to glutamate supplementation and displayed greatly enhanced sensitivity in a number of low pH foods, even when levels of free glutamate were as low as 0.22 mM. We thus show that the GAD system plays a major role in the survival of L. monocytogenes in acidic foods even when levels of free glutamate are low.
authors.affiliation: Department of Microbiology, University College Cork, Ireland.
authors.forename: P D
authors.initials: PD
authors.lastname: Cotter
authors.forename: K
authors.initials: K
authors.lastname: O'Reilly
authors.forename: C
authors.initials: C
authors.lastname: Hill
mesh_terms: D015169:Colony Count, Microbial; D005516:Food Microbiology; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000201:enzymology* / Q000254:growth & development; D009154:Mutation; D013997:Time Factors
chemical_list: D005968:Glutamate Decarboxylase