TY - JOUR
T1 - Synchrotron X-ray studies of the keel of the short-spined sea urchin Lytechinus variegatus
T2 - Absorption microtomography (microCT) and small beam diffraction mapping
AU - Stock, S. R.
AU - Barss, J.
AU - Dahl, T.
AU - Veis, A.
AU - Almer, J. D.
AU - De Carlo, F.
PY - 2003/5/1
Y1 - 2003/5/1
N2 - In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 μm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 μm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca1-xMgxCO3 of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.
AB - In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 μm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 μm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca1-xMgxCO3 of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.
KW - Lytechinus variegatus
KW - Microtomography (microCT)
KW - Sea urchin
KW - Synchrotron radiation
KW - Tooth
KW - X-ray diffraction
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U2 - 10.1007/s00223-002-1037-2
DO - 10.1007/s00223-002-1037-2
M3 - Article
C2 - 12721775
AN - SCOPUS:0042659485
SN - 0171-967X
VL - 72
SP - 555
EP - 566
JO - Calcified Tissue International
JF - Calcified Tissue International
IS - 5
ER -