title: Lactococcus lactis produces short-chain quinones that cross-feed Group B Streptococcus to activate respiration growth.
abstract: Quinones are essential components of the respiration chain that shuttle electrons between oxidoreductases. We characterized the quinones synthesized by Lactococcus lactis, a fermenting bacterium that activates aerobic respiration when a haem source is provided. Two distinct subgroups were characterized: Menaquinones (MK) MK-8 to MK-10, considered as hallmarks of L. lactis, are produced throughout growth. MK-3 and demethylMK-3 [(D)MK-3] are newly identified and are present only late in growth. Production of (D)MK-3 was conditional on the carbon sugar and on the presence of carbon catabolite regulator gene ccpA. Electron flux driven by both (D)MK fractions was shared between the quinol oxidase and extracellular acceptors O(2), iron and, with remarkable efficiency, copper. Purified (D)MK-3, but not MK-8-10, complemented a menB defect in L. lactis. We previously showed that a respiratory metabolism is activated in Group B Streptococcus (GBS) by exogenous haem and MK, and that this activity is implicated in virulence. Here we show that growing lactococci donate (D)MK to GBS to activate respiration and stimulate growth of this opportunist pathogen. We propose that conditions favouring (D)MK production in dense microbial ecosystems, as present in the intestinal tract, could favour implantation of (D)MK-scavengers like GBS within the complex.
authors.affiliation: Unité Bactéries Lactiques et Pathogènes Opportunistes, UR13888 INRA, Domaine de Vilvert, 78352 Jouy en Josas, France.
authors.forename: Lahcen
authors.initials: L
authors.lastname: Rezaïki
authors.forename: Gilles
authors.initials: G
authors.lastname: Lamberet
authors.forename: Aurélie
authors.initials: A
authors.lastname: Derré
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gruss
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaudu
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004579:Electron Transport; D006026:Glycoside Hydrolases / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D013294:Lactococcus lactis / Q000254:growth & development / Q000378:metabolism*; D009154:Mutation; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D011809:Quinones / Q000032:analysis* / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism; D013292:Streptococcus agalactiae / Q000254:growth & development; D024482:Vitamin K 2 / Q000032:analysis / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011809:Quinones; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria; D024482:Vitamin K 2; D003300:Copper; D007501:Iron; D006026:Glycoside Hydrolases; C019822:carbohydrase; D010100:Oxygen