DOI: 10.5061/dryad.zcrjdfndp
title: Complex morphologies of biogenic crystals emerge from anisotropic growth of symmetry-related facets

description: Directing crystal growth into complex morphologies is challenging, as
 crystals tend to adopt thermodynamically stable morphologies. Yet, many
 organisms form crystals with intricate morphologies, as exemplified by
 coccoliths, microscopic calcite crystal-arrays produced by unicellular
 algae. The complex morphologies of the coccolith crystals were
 hypothesized to materialize from numerous crystallographic facets,
 stabilized by fine-tuned interactions between organic molecules and the
 growing crystals. Using state-of-the-art electron tomography, we examined
 multiple stages of coccolith development in 3D. We found that the crystals
 are expressing only one set of symmetry-related crystallographic facets,
 which grow differentially to yield highly anisotropic shapes.
 Morphological chirality arises from positioning the crystals along
 specific edges of these same facets. Our findings show that manipulations
 of growth kinetics can yield complex crystalline morphologies.
description: Data for 'Complex morphologies of biogenic crystals emerge
 from anisotropic growth of symmetry related facets':
 Zipped folder 1: "Data" (22.42 GB)
 1. Sub-folder '1_Reconstructions_crystal stages 1-5':
 containing files of the reconstructed volumes of the five different
 coccolith growth stages  discussed throughout the main text, denoted as
 stages 1-5. <br>Apart from 'stage 3' which was acquired in
 BF-STEM mode with a microprobe, all other data was acquired using a
 nanoprobe, collected in HAADF-STEM mode. Data collected on Tecnai G2 F20
 S/TEM microscope, at room temperature conditions.<br>Files in .rec
 format. 2. Sub-folder '2_Reconstructions_repeated
 tilt': containing files of the reconstructed volumes of coccolith
 used as control to determine preservation of crystals after a rpeated tilt
 series, as presented in SI Figure 7. <br>Data collected on Tecnai G2
 F20 S/TEM microscope, at room teperature, operation in HAADF-STEM mode and
 using a nanoprobe.  File in .rec format.  3. Sub-folder
 '3_Reconstruction_plunge frozen coccolith': containing files of
 the reconstructed volume of the coccolith used as control to determine
 preservation of crystal structure in cryogenic conditions, as presented in
 SI Figure 3. <br>This coccolith was plunge frozen in liquid ethane
 immediately after extraction, and was not exposed to NaHClO. Data
 collected on Titan Krios G3i S/TEM microscope, at cryogenic conditions,
 operation in HAADF-STEM mode and using a nanoprobe.  File in .rec
 format.  4. Sub-folder '4_Segmentations':
 containing segmentations files (3D visualizations) of reconstructed
 volumes of the coccolith growth stages discussed throughout the main text,
 denoted as stages 1-5 (associated with the supplied reconstructions in
 sub-folder 1. See ''1_Reconstructions_crystal stages
 1-5'').<br>V units are colored orange, R units are colored
 blue. Data generated on Amira software. Files in .am format.
 5. Sub-folder '5_SEM images hypotonic solutions':
 containing SEM images of ICCs extracted into different hypotonic
 solutions, used for quantification of overall structural preservation, as
 presented in SI Figure 2. <br>In each solution conditions, 50 random
 coccoliths were imaged, and divided into one of three groups - 'good
 condition', 'partially deformed' and 'deformed'.
 Data collected on Sigma 500 SEM, at room temperature. Files in .tif
 format. 6. Sub-folder '6_volume renderings':
 containing files of whole volume renderings (3D visualization based on
 automatically-generated 3D pixels, relying on the image's data
 histogram) of the coccoliths presented in Figure 2 and in SI Figure
 3.<br>Data generated on Amira software. Files in .am
 format. Softwares required to open files:
 "*.rec" and "*.mrc" files, which are the
 reconstructed volumes, can be opened with the free ImageJ software, using
 the Slicer plugin.<br>"*.am" files, which are the label
 and surface files, were generated by Amira for 3D visualization. They can
 be opened by Amira or any other compatible sofwares.
 Zipped folder 2: "movies" (129 MB)
 This folder contains five movies of the tomograms and rendered
 volumes of all crystal growth stages (denoted as 'stages i-v').
 In each movie, four segmented units are shown (two R-units, in blue, and
 two V-units, in orange). All movies are at a resolution of 1398x930
 pixels. Files in .avi format.