Fingering instabilities in bacterial community phototaxis

ORAL

Abstract

Synechocystis sp PCC 6803 is a phototactic cyanobacterium that moves directionally in response to a light source. During phototaxis, these bacterial communities show emergent spatial organisation resulting in the formation of finger-like projections at the propagating front. In this study, we propose an analytical model that elucidates the underlying physical mechanisms which give rise to these spatial patterns. We describe the migrating front during phototaxis as a one-dimensional curve by considering the effects of phototactic bias, diffusion and surface tension. By considering the propagating front as composed of perturbations to a flat solution and using linear stability analysis, we predict a critical bias above which the finger-like projections appear as instabilities. We also predict the wavelengths of the fastest growing mode and the critical mode above which the instabilities disappear. We validate our predictions through comparisons to experimental data obtained by analysing images of phototaxis in Synechocystis communities. Our model also predicts the observed loss of instabilities in taxd1 mutants (cells with inactive TaxD1, an important photoreceptor in finger formation), by considering diffusion in mutually perpendicular directions and a lower, negative bias.

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Authors

  • Ritwika VPS

    University of California, Merced

  • C. Jennings

    Stanford University, None, none, Univ of California - Merced, Dr. Remeis-Sternwarte & ECAP, Universität Erlangen-Nürnberg, NASA GSFC, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, Goddard Space Flight Center-NASA, University of Nevada, Reno, Cal Poly - San Luis Obispo, Victoria University of Wellington, Wellington 6021, New Zealand, Penn State, Micron School of Materials Science & Engineering, Department of Physics, Boise State University, Autonomous University of Zacatecas, Micron School of Materials Science & Engineering, Boise State University, Naval Research Laboratory, Independent Researcher, Cornell University, UC Santa Cruz, Middle Georgia State University, University of California, Merced, Stanford University, California, Institute of Medical Biology, Singapore; Stanford University, California, University of California Merced, Kent State University, ORNL, UC Berkeley, LLNL, Physics, Hokkaido University, Japan, Physics, UC San Diego, Physics, California State University, Fresno, Department of Physics and Astronomy, California State University Long Beach, Long Beach, California 90840, USA, Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA, Department of Physics, Southern University of Science and Technology, Shenzen 518055, China, Virginia Tech, Sotera Defense Solutions, Inc., Univ of California - Santa Cruz, College of Staten Island, UC Irvine, Naval Research Laboratory, Washington, DC 20375, Virginia Tech, Blacksburg, VA 24061, University of California, Merced CA 95343

  • C. Jennings

    Stanford University, None, none, Univ of California - Merced, Dr. Remeis-Sternwarte & ECAP, Universität Erlangen-Nürnberg, NASA GSFC, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, Goddard Space Flight Center-NASA, University of Nevada, Reno, Cal Poly - San Luis Obispo, Victoria University of Wellington, Wellington 6021, New Zealand, Penn State, Micron School of Materials Science & Engineering, Department of Physics, Boise State University, Autonomous University of Zacatecas, Micron School of Materials Science & Engineering, Boise State University, Naval Research Laboratory, Independent Researcher, Cornell University, UC Santa Cruz, Middle Georgia State University, University of California, Merced, Stanford University, California, Institute of Medical Biology, Singapore; Stanford University, California, University of California Merced, Kent State University, ORNL, UC Berkeley, LLNL, Physics, Hokkaido University, Japan, Physics, UC San Diego, Physics, California State University, Fresno, Department of Physics and Astronomy, California State University Long Beach, Long Beach, California 90840, USA, Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA, Department of Physics, Southern University of Science and Technology, Shenzen 518055, China, Virginia Tech, Sotera Defense Solutions, Inc., Univ of California - Santa Cruz, College of Staten Island, UC Irvine, Naval Research Laboratory, Washington, DC 20375, Virginia Tech, Blacksburg, VA 24061, University of California, Merced CA 95343

  • C. Jennings

    Stanford University, None, none, Univ of California - Merced, Dr. Remeis-Sternwarte & ECAP, Universität Erlangen-Nürnberg, NASA GSFC, Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, Goddard Space Flight Center-NASA, University of Nevada, Reno, Cal Poly - San Luis Obispo, Victoria University of Wellington, Wellington 6021, New Zealand, Penn State, Micron School of Materials Science & Engineering, Department of Physics, Boise State University, Autonomous University of Zacatecas, Micron School of Materials Science & Engineering, Boise State University, Naval Research Laboratory, Independent Researcher, Cornell University, UC Santa Cruz, Middle Georgia State University, University of California, Merced, Stanford University, California, Institute of Medical Biology, Singapore; Stanford University, California, University of California Merced, Kent State University, ORNL, UC Berkeley, LLNL, Physics, Hokkaido University, Japan, Physics, UC San Diego, Physics, California State University, Fresno, Department of Physics and Astronomy, California State University Long Beach, Long Beach, California 90840, USA, Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA, Department of Physics, Southern University of Science and Technology, Shenzen 518055, China, Virginia Tech, Sotera Defense Solutions, Inc., Univ of California - Santa Cruz, College of Staten Island, UC Irvine, Naval Research Laboratory, Washington, DC 20375, Virginia Tech, Blacksburg, VA 24061, University of California, Merced CA 95343