title: Bacterial social networks: structure and composition of Myxococcus xanthus outer membrane vesicle chains.
abstract: The social soil bacterium, Myxococcus xanthus, displays a variety of complex and highly coordinated behaviours, including social motility, predatory rippling and fruiting body formation. Here we show that M. xanthus cells produce a network of outer membrane extensions in the form of outer membrane vesicle chains and membrane tubes that interconnect cells. We observed peritrichous display of vesicles and vesicle chains, and increased abundance in biofilms compared with planktonic cultures. By applying a range of imaging techniques, including three-dimensional (3D) focused ion beam scanning electron microscopy, we determined these structures to range between 30 and 60 nm in width and up to 5 μm in length. Purified vesicle chains consist of typical M. xanthus lipids, fucose, mannose, N-acetylglucosamine and N-acetylgalactoseamine carbohydrates and a small set of cargo protein. The protein content includes CglB and Tgl outer membrane proteins known to be transferable between cells in a contact-dependent manner. Most significantly, the 3D organization of cells within biofilms indicates that cells are connected via an extensive network of membrane extensions that may connect cells at the level of the periplasmic space. Such a network would allow the transfer of membrane proteins and other molecules between cells, and therefore could provide a mechanism for the coordination of social activities.
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94025, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Remis
authors.forename: Dongguang
authors.initials: D
authors.lastname: Wei
authors.forename: Amita
authors.initials: A
authors.lastname: Gorur
authors.forename: Marcin
authors.initials: M
authors.lastname: Zemla
authors.forename: Jessica
authors.initials: J
authors.lastname: Haraga
authors.forename: Simon
authors.initials: S
authors.lastname: Allen
authors.forename: H Ewa
authors.initials: HE
authors.lastname: Witkowska
authors.forename: J William
authors.initials: JW
authors.lastname: Costerton
authors.forename: James E
authors.initials: JE
authors.lastname: Berleman
authors.forename: Manfred
authors.initials: M
authors.lastname: Auer
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D018441:Biofilms; D002462:Cell Membrane / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D016941:Myxococcus xanthus / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D001425:Bacterial Outer Membrane Proteins