title: Hydrogen peroxide linked to lysine oxidase activity facilitates biofilm differentiation and dispersal in several gram-negative bacteria.
abstract: The marine bacterium Pseudoalteromonas tunicata produces an antibacterial and autolytic protein, AlpP, which causes death of a subpopulation of cells during biofilm formation and mediates differentiation, dispersal, and phenotypic variation among dispersal cells. The AlpP homologue (LodA) in the marine bacterium Marinomonas mediterranea was recently identified as a lysine oxidase which mediates cell death through the production of hydrogen peroxide. Here we show that AlpP in P. tunicata also acts as a lysine oxidase and that the hydrogen peroxide generated is responsible for cell death within microcolonies during biofilm development in both M. mediterranea and P. tunicata. LodA-mediated biofilm cell death is shown to be linked to the generation of phenotypic variation in growth and biofilm formation among M. mediterranea biofilm dispersal cells. Moreover, AlpP homologues also occur in several other gram-negative bacteria from diverse environments. Our results show that subpopulations of cells in microcolonies also die during biofilm formation in two of these organisms, Chromobacterium violaceum and Caulobacter crescentus. In all organisms, hydrogen peroxide was implicated in biofilm cell death, because it could be detected at the same time as the killing occurred, and the addition of catalase significantly reduced biofilm killing. In C. violaceum the AlpP-homologue was clearly linked to biofilm cell death events since an isogenic mutant (CVMUR1) does not undergo biofilm cell death. We propose that biofilm killing through hydrogen peroxide can be linked to AlpP homologue activity and plays an important role in dispersal and colonization across a range of gram-negative bacteria.
authors.affiliation: School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, Biological Sciences Building, University of New South Wales, Kensington, Sydney, NSW 2052, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Mai-Prochnow
authors.forename: Patricia
authors.initials: P
authors.lastname: Lucas-Elio
authors.forename: Suhelen
authors.initials: S
authors.lastname: Egan
authors.forename: Torsten
authors.initials: T
authors.lastname: Thomas
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Webb
authors.forename: Antonio
authors.initials: A
authors.lastname: Sanchez-Amat
authors.forename: Staffan
authors.initials: S
authors.lastname: Kjelleberg
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D016935:Caulobacter crescentus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D002861:Chromobacterium / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D017353:Gene Deletion; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D053544:Marinomonas / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D050296:Microbial Viability; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000187:drug effects / Q000201:enzymology / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D006899:Mixed Function Oxygenases; C100031:lysine monooxygenase