title: Water Dynamics in Shewanella oneidensis at Ambient and High Pressure using Quasi-Elastic Neutron Scattering.
abstract: Quasielastic neutron scattering (QENS) is an ideal technique for studying water transport and relaxation dynamics at pico- to nanosecond timescales and at length scales relevant to cellular dimensions. Studies of high pressure dynamic effects in live organisms are needed to understand Earth's deep biosphere and biotechnology applications. Here we applied QENS to study water transport in Shewanella oneidensis at ambient (0.1 MPa) and high (200 MPa) pressure using H/D isotopic contrast experiments for normal and perdeuterated bacteria and buffer solutions to distinguish intracellular and transmembrane processes. The results indicate that intracellular water dynamics are comparable with bulk diffusion rates in aqueous fluids at ambient conditions but a significant reduction occurs in high pressure mobility. We interpret this as due to enhanced interactions with macromolecules in the nanoconfined environment. Overall diffusion rates across the cell envelope also occur at similar rates but unexpected narrowing of the QENS signal appears between momentum transfer values Q = 0.7-1.1 Å(-1) corresponding to real space dimensions of 6-9 Å. The relaxation time increase can be explained by correlated dynamics of molecules passing through Aquaporin water transport complexes located within the inner or outer membrane structures.
authors.affiliation: Chemistry Department, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, UK.|Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Foglia
authors.affiliation: Chemistry Department, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
authors.forename: Rachael
authors.initials: R
authors.lastname: Hazael
authors.affiliation: Heinz Maier-Leibnitz Zentrum (MLZ) and Physics Department, Technisches Universität München, Lichtenbergstrasse 1, D-85748 Garching, Germany.
authors.forename: Giovanna G
authors.initials: GG
authors.lastname: Simeoni
authors.affiliation: Jülich Center for Neutron Sciences at MLZ, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, D-85748 Garching, Germany.
authors.forename: Marie-Sousai
authors.initials: MS
authors.lastname: Appavou
authors.affiliation: Life Sciences Group, Carl-Ivar Brändén Building, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble cedex 9, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Moulin
authors.affiliation: Life Sciences Group, Carl-Ivar Brändén Building, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble cedex 9, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Haertlein
authors.affiliation: Life Sciences Group, Carl-Ivar Brändén Building, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble cedex 9, France.|Faculty of Natural Sciences/ISTM, Keele University, Staffordshire ST5 5BG, UK.
authors.forename: V
authors.initials: V
authors.lastname: Trevor Forsyth
authors.affiliation: Science Division, Institut Laue-Langevin, CS 20156, 71 avenue des Martyrs, 38042 Grenoble cedex 9, France.
authors.forename: Tilo
authors.initials: T
authors.lastname: Seydel
authors.affiliation: Laboratoire de Géologie de Lyon, UMR 5276, Université Lyon 1-ENS de Lyon-CNRS, 2 rue Raphaël Dubois, 69622 Villeurbanne, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Daniel
authors.affiliation: Chemistry Department, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, UK.|Biomolecular &Analytical Mass Spectrometry, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Meersman
authors.affiliation: Chemistry Department, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
authors.forename: Paul F
authors.initials: PF
authors.lastname: McMillan
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001692:Biological Transport; D033363:Neutron Diffraction; D011312:Pressure; D020592:Shewanella / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D014867:Water