Dumont M, Tütken T, Kostka A, Duarte M J, Borodin S
Max-Planck-Institute for Iron Research, 40237 Düsseldorf, Germany.
University of Mainz, Institute for Geosciences, 55128 Mainz, Germany.
J Struct Biol. 2014 Apr;186(1):38-48. doi: 10.1016/j.jsb.2014.02.006. Epub 2014 Feb 17.
Pigmented tooth enamel occurs in several vertebrate clades, ranging from mammals to fish. Although an iron compound is associated with this orange to red colored pigmentation, its chemical and structural organization within the enamel is unknown. To determine the nature of the iron compound, we investigated heavily pigmented teeth of the northern short-tailed shrew Blarina brevicauda using combined characterization techniques such as scanning and transmission electron microscopy and synchrotron X-ray diffraction. We found that the pigmentation of the enamel with an iron content of around 8wt% results from a close to amorphous magnetite phase deposited around the nm-sized enamel crystals. Furthermore, the influence of the pigmentation on the enamel hardness was determined by nanoindentation measurements. Finally, the biomechanical function and biological context are discussed in light of the obtained results.
有色素沉着的牙釉质存在于从哺乳动物到鱼类的多个脊椎动物类群中。尽管一种铁化合物与这种橙色到红色的色素沉着有关，但其在牙釉质中的化学和结构组织尚不清楚。为了确定铁化合物的性质，我们使用扫描和透射电子显微镜以及同步加速器X射线衍射等联合表征技术，研究了北短尾鼩鼱（Blarina brevicauda）色素沉着严重的牙齿。我们发现，铁含量约为8wt%的牙釉质色素沉着是由沉积在纳米级牙釉质晶体周围的近无定形磁铁矿相引起的。此外，通过纳米压痕测量确定了色素沉着对牙釉质硬度的影响。最后，根据获得的结果讨论了生物力学功能和生物学背景。
