title: Lactococcus lactis SpOx spontaneous mutants: a family of oxidative-stress-resistant dairy strains.
abstract: Numerous industrial bacteria generate hydrogen peroxide (H(2)O(2)), which may inhibit the growth of other bacteria in mixed ecosystems. We isolated spontaneous oxidative-stress-resistant (SpOx) Lactococcus lactis mutants by using a natural selection method with milk-adapted strains on dairy culture medium containing H(2)O(2). Three SpOx mutants displayed greater H(2)O(2) resistance. One of them, SpOx3, demonstrated better behavior in different oxidative-stress situations: (i) higher long-term survival upon aeration in LM17 and milk and (ii) the ability to grow with H(2)O(2)-producing Lactobacillus delbrueckii subsp. delbrueckii strains. Furthermore, the transit kinetics of the SpOx3 mutant in the digestive tract of a human flora-associated mouse model was not affected.
authors.affiliation: Unité de Recherches Laitières et de Génetique, INRA, Domaine de Vilvert, 78352 Jouy en Josas cedex, France.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Rochat
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Gratadoux
authors.forename: Gérard
authors.initials: G
authors.lastname: Corthier
authors.forename: Bérard
authors.initials: B
authors.lastname: Coqueran
authors.forename: Maria-Elena
authors.initials: ME
authors.lastname: Nader-Macias
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gruss
authors.forename: Philippe
authors.initials: P
authors.lastname: Langella
mesh_terms: D000818:Animals; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D013294:Lactococcus lactis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D051379:Mice; D008892:Milk / Q000382:microbiology; D009154:Mutation; D018384:Oxidative Stress
chemical_list: D006861:Hydrogen Peroxide