DOI: 10.5061/dryad.4xgxd25g0
title: Curved crease origami at cellular scales enables hyper-extensibility of Lacrymaria olor

description: Eukaryotic cells undergo dramatic morphological changes during cell
 division, phagocytosis, and motility. Fundamental limits of cellular
 morphodynamics such as how fast or how much cellular shapes can change
 without harm to a living cell remain poorly understood. Here we describe
 hyper-extensibility in the single-celled protist Lacrymaria olor, a 40 μm
 cell which is capable of reversible and repeatable extensions (neck-like
 protrusions) up to 1500 μm in 20 seconds. We discover that a unique and
 intricate organization of cortical cytoskeleton and membrane enables these
 hyper-extensions that can be described as the first cellular scale curved
 crease origami. Furthermore, we show how these topological singularities
 including dcones and twisted domain walls provide a geometrical control
 mechanism for the deployment of membrane and microtubule sheets as they
 repeatably spool thousands of times from the cell body. We lastly build
 physical origami models to understand how these topological singularities
 provide a mechanism for the cell to control the hyper-extensile deployable
 structure. This new geometrical motif where a cell employs curved crease
 origami to perform a physiological function has wide-ranging implications
 in understanding cellular morphodynamics and direct applications in
 deployable micro-robotics.
description: The contents of this dataset were used in the associated
 manuscript. A combination of microscopy (confocal fluorescence, scanning
 electron microscopy, transmission electron microscopy, high-speed DIC
 imaging) and physical models (origami) were all required to understand the
 ultrastructure of the membrane and cortical cytoskeleton in <em>L.
 olor</em>. From this data and its characterization and
 quantification, we were able to discover that the geometry and subcellular
 architecture within the cell gives rise to its unique hunting behavior:
 rapid, reversible hyper-extensions. 
description: # Curved crease origami and topological singularities enable
 hyperextensibility of *L. olor* The contents of this dataset were used in
 the associated manuscript. A combination of microscopy (confocal
 fluorescence, scanning electron microscopy, transmission electron
 microscopy, high-speed DIC imaging) and physical models (origami) were all
 required to understand the ultrastructure of the membrane and cortical
 cytoskeleton in L. olor. From this data and its characterization and
 quantification, we were able to discover that the geometry and subcellular
 architecture within the cell give rise to its unique hunting behavior:
 rapid, reversible hyper-extensions. **Description of the data and file
 structure** This dataset contains several forms of data which were used in
 the manuscript. The file names are labeled by the headers:
 Figure_CollectionMethod_IdentifyingName.  The Figure 2 headed file
 contains the alpha-tubulin-stained z-stack of a cell collected using a
 confocal microscope (Confocal_LacrymariaTubulinCell1.czi). Any .czi files
 can be opened using ImageJ or FIJI programs. The Figure 3 headed files are
 additional confocal z-stacks of tubulin-stained cells labeled
 Confocal_LacrymariaTubulinCell1.czi and
 Confocal_LacrymariaTubulinCell3.czi which can be opened using ImageJ or
 FIJI programs. Additionally, the SEM image Figure3_SEM_Lacrymaria.tif from
 this figure can be opened using any image viewing software.  All data with
 Figure 4 headings are TEM sections of fixed *Lacrymaria olor* cells. The
 raw data (.mrc files) can be opened for viewing using ImageJ or FIJI. The
 images can be stitched together using any package, and stitching was done
 in our paper by downloading IMOD, and running etomo within IMOD on the
 .mrc files with the .ecd (existing edge displacement) file in the same
 directory. Each set containing a .mrc, a .mrc.mdoc, and a .ecd file needs
 to be put in a folder before processing. Additionally, any .jpeg, .png,
 .mp4, or .tif files can be opened using any image viewing software. All
 data with Figure 5 headings come from the origami experiments. Any .jpeg,
 .png, .mp4, or .tif files can be opened using any image viewing software.
 Any .csv files can be opened using excel, sheets, or any text editor.
 **Code/Software** All code and related files are stored in the Zenodo
 archive.  There are 3 sets of code which are also in this dataset. In
 Figures 4 and 5 we compute the bending and twisting energies of
 microtubule ribbons in the helical architecture found in L. olor. There is
 a script called Figure4_Matlab_Energetics.m which can be run using Matlab,
 and which requires the measurements in the folders 2Image,
 20180725_longstraightcell, 20180725_shortcell. The output data for this is
 then plotted using the script Figure4_Python_EnergyPlots.py using Python.
 There are additional plotting scripts which are in folders titled
 TEM_Measurements_Figure4 and TEM_PleatDepthPlots_Figure4. The
 PleatDepthPlots folder contains measurements of the depths of the Membrane
 Pleats for two cells. The Measurements folder contains measurements of the
 number of ribbons found in each pleat. The script as well as measurements
 made which are required to run the script are in each folder. Both scripts
 can be run using Python.