title: Chirality in microbial biofilms is mediated by close interactions between the cell surface and the substratum.
abstract: From microbial biofilms to human migrations, spatial competition is central to the evolutionary history of many species. The boundary between expanding populations is the focal point of competition for space and resources and is of particular interest in ecology. For all Escherichia coli strains studied here, these boundaries move in a counterclockwise direction even when the competing strains have the same fitness. We find that chiral growth of bacterial colonies is strongly suppressed by the expression of extracellular features such as adhesive structures and pili. Experiments with other microbial species show that chiral growth is found in other bacteria and exclude cell wall biosynthesis and anisotropic shape as the primary causes of chirality. Instead, intimate contact with the substratum is necessary for chirality. Our results demonstrate that through a handful of surface molecules cells can fundamentally reorganize their migration patterns, which might affect intra- and interspecific competitions through colony morphology or other mechanisms.
authors.affiliation: The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Jauffred
authors.affiliation: Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Munk Vejborg
authors.affiliation: Department of Physics and Graduate Program in Bioinformatics, Boston University, Boston, USA.
authors.forename: Kirill S
authors.initials: KS
authors.lastname: Korolev
authors.affiliation: The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Stanley
authors.initials: S
authors.lastname: Brown
authors.affiliation: The Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Lene B
authors.identifier: 0000-0003-2923-2844
authors.initials: LB
authors.lastname: Oddershede
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D004926:Escherichia coli / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D009068:Movement; D013045:Species Specificity; D013499:Surface Properties