title: Ice-nucleating bacteria control the order and dynamics of interfacial water.
abstract: Ice-nucleating organisms play important roles in the environment. With their ability to induce ice formation at temperatures just below the ice melting point, bacteria such as Pseudomonas syringae attack plants through frost damage using specialized ice-nucleating proteins. Besides the impact on agriculture and microbial ecology, airborne P. syringae can affect atmospheric glaciation processes, with consequences for cloud evolution, precipitation, and climate. Biogenic ice nucleation is also relevant for artificial snow production and for biomimetic materials for controlled interfacial freezing. We use interface-specific sum frequency generation (SFG) spectroscopy to show that hydrogen bonding at the water-bacteria contact imposes structural ordering on the adjacent water network. Experimental SFG data and molecular dynamics simulations demonstrate that ice-active sites within P. syringae feature unique hydrophilic-hydrophobic patterns to enhance ice nucleation. The freezing transition is further facilitated by the highly effective removal of latent heat from the nucleation site, as apparent from time-resolved SFG spectroscopy.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Ravindra
authors.initials: R
authors.lastname: Pandey
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Kota
authors.initials: K
authors.lastname: Usui
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Livingstone
authors.affiliation: Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: Sean A
authors.initials: SA
authors.lastname: Fischer
authors.affiliation: Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: Jim
authors.initials: J
authors.lastname: Pfaendtner
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Ellen H G
authors.initials: EH
authors.lastname: Backus
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nagata
authors.affiliation: Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
authors.forename: Janine
authors.identifier: 0000-0002-1278-0054
authors.initials: J
authors.lastname: Fröhlich-Nowoisky
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Lars
authors.identifier: 0000-0001-5096-2679
authors.initials: L
authors.lastname: Schmüser
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Sergio
authors.initials: S
authors.lastname: Mauri
authors.affiliation: Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
authors.forename: Jan F
authors.initials: JF
authors.lastname: Scheel
authors.affiliation: Institute for Terrestrial and Planetary Atmospheres/School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Daniel A
authors.identifier: 0000-0001-7732-3922
authors.initials: DA
authors.lastname: Knopf
authors.affiliation: Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pöschl
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.
authors.forename: Mischa
authors.initials: M
authors.lastname: Bonn
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.; Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: Tobias
authors.initials: T
authors.lastname: Weidner
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D006860:Hydrogen Bonding; D007053:Ice; D056004:Molecular Dynamics Simulation; D010944:Plants / Q000382:microbiology; D044224:Pseudomonas syringae / Q000378:metabolism* / Q000472:pathogenicity; D013696:Temperature; D014867:Water / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007053:Ice; C063113:ice nucleation protein; D014867:Water
keywords: Ice nucleation; Ice protein; Pseudomonas Syringae; sum frequency generation