title: Broken detailed balance at mesoscopic scales in active biological systems.
abstract: Systems in thermodynamic equilibrium are not only characterized by time-independent macroscopic properties, but also satisfy the principle of detailed balance in the transitions between microscopic configurations. Living systems function out of equilibrium and are characterized by directed fluxes through chemical states, which violate detailed balance at the molecular scale. Here we introduce a method to probe for broken detailed balance and demonstrate how such nonequilibrium dynamics are manifest at the mesosopic scale. The periodic beating of an isolated flagellum from Chlamydomonas reinhardtii exhibits probability flux in the phase space of shapes. With a model, we show how the breaking of detailed balance can also be quantified in stationary, nonequilibrium stochastic systems in the absence of periodic motion. We further demonstrate such broken detailed balance in the nonperiodic fluctuations of primary cilia of epithelial cells. Our analysis provides a general tool to identify nonequilibrium dynamics in cells and tissues.
authors.affiliation: Drittes Physikalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany. The Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Battle
authors.affiliation: The Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 München, Germany. Lewis-Sigler Institute for Integrative Genomics and Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Chase P
authors.initials: CP
authors.lastname: Broedersz
authors.affiliation: Drittes Physikalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany. The Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Nikta
authors.initials: N
authors.lastname: Fakhri
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
authors.forename: Veikko F
authors.initials: VF
authors.lastname: Geyer
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Howard
authors.affiliation: Drittes Physikalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany. The Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. fcmack@gmail.com christoph.schmidt@phys.uni-goettingen.de.
authors.forename: Christoph F
authors.initials: CF
authors.lastname: Schmidt
authors.affiliation: The Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. Department of Physics and Astronomy, Vrije Universiteit, Amsterdam, Netherlands. fcmack@gmail.com christoph.schmidt@phys.uni-goettingen.de.
authors.forename: Fred C
authors.initials: FC
authors.lastname: MacKintosh
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000502:physiology*; D002923:Cilia / Q000502:physiology; D004285:Dogs; D004847:Epithelial Cells / Q000502:physiology; D005407:Flagella / Q000502:physiology*; D061985:Madin Darby Canine Kidney Cells; D008853:Microscopy / Q000379:methods; D008954:Models, Biological; D009038:Motion; D013816:Thermodynamics