title: Exopolysaccharide microchannels direct bacterial motility and organize multicellular behavior.
abstract: The myxobacteria are a family of soil bacteria that form biofilms of complex architecture, aligned multilayered swarms or fruiting body structures that are simple or branched aggregates containing myxospores. Here, we examined the structural role of matrix exopolysaccharide (EPS) in the organization of these surface-dwelling bacterial cells. Using time-lapse light and fluorescence microscopy, as well as transmission electron microscopy and focused ion beam/scanning electron microscopy (FIB/SEM) electron microscopy, we found that Myxococcus xanthus cell organization in biofilms is dependent on the formation of EPS microchannels. Cells are highly organized within the three-dimensional structure of EPS microchannels that are required for cell alignment and advancement on surfaces. Mutants lacking EPS showed a lack of cell orientation and poor colony migration. Purified, cell-free EPS retains a channel-like structure, and can complement EPS-mutant motility defects. In addition, EPS provides the cooperative structure for fruiting body formation in both the simple mounds of M. xanthus and the complex, tree-like structures of Chondromyces crocatus. We furthermore investigated the possibility that EPS impacts community structure as a shared resource facilitating cooperative migration among closely related isolates of M. xanthus.
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.|Department of Biology, St Mary's College, Moraga, CA, USA.|Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Berleman
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Marcin
authors.initials: M
authors.lastname: Zemla
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Remis
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.|State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
authors.forename: Annie E
authors.initials: AE
authors.lastname: Davis
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.|Department of Biology, St Mary's College, Moraga, CA, USA.
authors.forename: Alexandra N
authors.initials: AN
authors.lastname: Worth
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.|Department of Biology, St Mary's College, Moraga, CA, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: West
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Angela
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
authors.forename: Hanwool
authors.initials: H
authors.lastname: Park
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Bosneaga
authors.affiliation: FEI, Inc, Hillsboro, OR, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: van Leer
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Wenting
authors.initials: W
authors.lastname: Tsai
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Zusman
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
authors.forename: Manfred
authors.initials: M
authors.lastname: Auer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D016941:Myxococcus xanthus / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial