Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA.
J Struct Biol. 2009 Dec;168(3):452-66. doi: 10.1016/j.jsb.2009.07.013. Epub 2009 Jul 16.
Microstructure of the teeth of the sea urchin Lytechinus variegatus was investigated using optical microscopy, SEM (scanning electron microscopy) and SIMS (secondary ion mass spectroscopy). The study focused on the internal structure of the first-stage mineral structures of high Mg calcite (primary, secondary and carinar process plates, prisms) and on morphology of the columns of second-stage mineral (very high Mg calcite) that cement the first-stage material together. Optical micrographs under polarized light revealed contrast in the centers (midlines) of carinar process plates and in prisms in polished sections; staining of primary and carinar process plates revealed significant dye uptake at the plate centers. Demineralization with and without fixation revealed that the midlines of primary and carinar process plates (but not secondary plates) and the centers of prisms differed from the rest of the plate or prism, and SIMS showed proteins concentrated in these plate centers. SEM was used to study the morphology of columns, the fracture surfaces of mature teeth and the 3D morphology of prisms. These observations of internal structures in plates and prisms offer new insight into the mineralization process and suggest an important role for protein inclusions within the first-stage mineral. Some of the 3D structures not reported previously, such as twisted prisms and stacks of carinar process plates with nested wrinkles, may represent structural strengthening strategies.
利用光学显微镜、扫描电子显微镜（SEM）和二次离子质谱（SIMS）研究了海胆 Lytechinus variegatus 的牙齿微观结构。该研究集中于高镁方解石（初级、次级和齿突板、棱柱）的第一级矿化结构的内部结构，以及将第一级材料粘结在一起的第二级矿化（非常高镁方解石）柱的形态。偏光显微镜下的光镜照片显示，在抛光部分的齿突板中心（中线）和棱柱中有对比度；对初级和齿突板进行染色显示，在板中心有明显的染料吸收。脱矿质处理和固定处理都表明，初级和齿突板的中线（但不是次级板）和棱柱的中心与板或棱柱的其余部分不同，SIMS 显示蛋白质集中在这些板中心。SEM 用于研究柱的形态、成熟牙齿的断裂表面和棱柱的 3D 形态。这些对板和棱柱内部结构的观察为矿化过程提供了新的见解，并表明蛋白质夹杂物在第一级矿化中具有重要作用。一些以前未报道的 3D 结构，如扭曲的棱柱和嵌套褶皱的齿突板堆叠，可能代表结构强化策略。
