Three-dimensional micro architecture of the plates (primary, secondary, and carinar process) in the developing tooth of Lytechinus variegatus revealed by synchrotron X-ray absorption microtomography (microCT)
Three-dimensional micro architecture of the plates (primary, secondary, and carinar process) in the developing tooth of Lytechinus variegatus revealed by synchrotron X-ray absorption microtomography (microCT)
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DOI：
10.1016/j.jsb.2003.09.004
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发表时间：
2003-12-01
影响因子：
3
通讯作者：
De Carlo, F
中科院分区：
文献类型：
--
作者：
Stock, SR;Ignatiev, KI;De Carlo, F
本文报告了首次对海胆牙齿整个横截面进行的非侵入性体积研究，其中可以解析单个方解石结构元素。使用同步加速器 microCT（显微计算机断层扫描）和 1.66 mum 体素（体积元素）对两块完整的 Lytechinus variegatus 牙齿横截面碎片进行了研究。这些碎片来自胚芽，即矿物质含量迅速增加的牙齿区域；第一个碎片来自龙骨发育的区域，第二个碎片来自龙骨正在发育的区域。初级板、次级板、隆凸过程板、棱镜和层状-针状复合体的元素都得到了解析。将 microCT 数据与染色薄片的光学显微照片进行比较，证实了特征微结构特征的识别和测量尺寸。与单个或连续切片相比，体积数值数据集中更清楚地揭示了增强结构（板和棱柱）的相互作用。众所周知，喀马洛特牙齿中的主板和棱镜的位置是为了提高抗弯曲性（可称为主弯曲），但所提供的数据提供了对隆突加工板的机械作用的新理解，即与龙骨中抵抗牙齿绕第二轴横向或横向弯曲所需的几何形状一致的几何形状。结合横向龙骨加固的牙齿坚固性的增加表明，隆突的相对发展（朝向类似于 L. variegatus 的几何形状）是一个特征，可以用来推断哪些海胆在搅拌齿象中是最原始的，而在卡玛罗齿象中是更原始的。 (C) 2003 Elsevier Inc. 保留所有权利。
This paper reports the first noninvasive, volumetric study of entire cross-sections of a sea urchin tooth in which the individual calcite structural elements could be resolved. Two cross-sectionally intact fragments of a Lytechinus variegatus tooth were studied with synchrotron microCT (microcomputed tomography) with 1.66 mum voxels (volume elements). These fragments were from the plumula, that is the tooth zone with rapidly increasing levels of mineral; one fragment was from a position aboral of where the keel developed and the second was from the zone where the keel was developing. The primary plates, secondary plates, carinar process plates, prisms, and elements of the lamellar-needle complex were resolved. Comparison of the microCT data with optical micrographs of stained thin sections confirmed the identifications and measured dimensions of the characteristic microarchitectural features. The interplay of reinforcing structures (plates and prisms) was more clearly revealed in the volumetric numerical data sets than in single or sequential slices. While it is well known that the primary plates and prisms in camarodont teeth are situated to improve resistance to bending (which can be termed primary bending), the data presented provide a new understanding of the mechanical role of the carinar process plates, that is, a geometry consistent with that required in the keel to resist lateral or transverse bending of the tooth about a second axis. The increase in robustness of teeth incorporating lateral keel reinforcement suggests that the relative development of carinar processes (toward a geometry similar to that of L. variegatus) is a character which can be used to infer which sea urchins among the stirodonts are most primitive and among the camarodonts which are more primitive. (C) 2003 Elsevier Inc. All rights reserved.