TY - JOUR
T1 - 3D Distribution of Biomineral and Chitin Matrix in the Stomatopod Dactyl Club by High Energy XRD-CT
AU - Erik Køppen Christensen, Thorbjørn
AU - Østergaard, Maja
AU - Gutowski, Olof
AU - Dippel, Ann-Christin
AU - Birkedal, Henrik
PY - 2024
Y1 - 2024
N2 - Stomatopods are ferocious hunters that use weaponized appendages to strike down their pray. The clubs of species such as Odontodactylus scyllarus undergo tremendous forces, and in consequence they have intricate structures, consisting of hydroxyapatite, chitin, amorphous calcium phosphate and carbonate, and occasionally calcite. These materials are distributed differently across the four major zones of the dactyl club: the impact, periodic lateral and medial, and striated regions. While stomatopod clubs and their structure have been studied for a long time, studies have thus far been constrained to 2D mapping experiments with moderate resolution due to difficulties in preparing whole club thin sections, and absorption tomography that gives information on densities but not molecular length scales. To address this problem, and shed light on the structure of entire clubs, we herein used X-ray powder diffraction computed tomography (XRD-CT) using high energy X-rays at the P07 beamline of PETRA-III to allow penetrating the large samples whilst still obtaining high resolution information. This allowed mapping the 3D distribution of diffraction phases including the biomineral apatite and the semi-crystal chitin matrix. This showed that hydroxyapatite forms an envelope around the club, and that chitin forms 2D sheets in the periodic region of the club.
AB - Stomatopods are ferocious hunters that use weaponized appendages to strike down their pray. The clubs of species such as Odontodactylus scyllarus undergo tremendous forces, and in consequence they have intricate structures, consisting of hydroxyapatite, chitin, amorphous calcium phosphate and carbonate, and occasionally calcite. These materials are distributed differently across the four major zones of the dactyl club: the impact, periodic lateral and medial, and striated regions. While stomatopod clubs and their structure have been studied for a long time, studies have thus far been constrained to 2D mapping experiments with moderate resolution due to difficulties in preparing whole club thin sections, and absorption tomography that gives information on densities but not molecular length scales. To address this problem, and shed light on the structure of entire clubs, we herein used X-ray powder diffraction computed tomography (XRD-CT) using high energy X-rays at the P07 beamline of PETRA-III to allow penetrating the large samples whilst still obtaining high resolution information. This allowed mapping the 3D distribution of diffraction phases including the biomineral apatite and the semi-crystal chitin matrix. This showed that hydroxyapatite forms an envelope around the club, and that chitin forms 2D sheets in the periodic region of the club.
KW - Stomatopod dactyl club
KW - Biomineralization
KW - Amorphous biomineral
KW - XRD-CT
U2 - 10.1016/j.jsb.2024.108136
DO - 10.1016/j.jsb.2024.108136
M3 - Journal article
C2 - 39384001
SN - 1047-8477
VL - 216
JO - Journal of Structural Biology
JF - Journal of Structural Biology
M1 - 108136
ER -