Lourdes R. Couoh , Lauro Bucio , José Luis Ruvalcaba , Britta Manoel , Tengteng Tang , Aurélien Gourrier , Kathryn Grandfield
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引用次数: 0
Abstract
In humans, the growth pattern of the acellular extrinsic fibre cementum (AEFC) has been useful to estimate the age-at-death. However, the structural organization behind such a pattern remains poorly understood. In this study tooth cementum from seven individuals from a Mexican modern skeletal series were analyzed with the aim of unveiling the AEFC collagenous and mineral structure using multimodal imaging approaches. The organization of collagen fibres was first determined using: light microscopy, transmission electron microscopy (TEM), electron tomography, and plasma FIB scanning electron microscopy (PFIB-SEM) tomography. The mineral properties were then investigated using: synchrotron small-angle X-ray scattering (SAXS) for T-parameter (correlation length between mineral particles); synchrotron X-ray diffraction (XRD) for L-parameter (mineral crystalline domain size estimation), alignment parameter (crystals preferred orientation) and lattice parameters a and c; as well as synchrotron X-ray fluorescence for spatial distribution of calcium, phosphorus and zinc. Results show that Sharpey’s fibres branched out fibres that cover and uncover other collagen bundles forming aligned arched structures that are joined by these same fibres but in a parallel fashion. The parallel fibres are not set as a continuum on the same plane and when they are superimposed project the AEFC incremental lines due to the collagen birefringence. The orientation of the apatite crystallites is subject to the arrangement of the collagen fibres, and the obtained parameter values along with the elemental distribution maps, revealed this mineral tissue as relatively homogeneous. Therefore, no intrinsic characteristics of the mineral phase could be associated with the alternating AEFC incremental pattern.
在人类中,细胞外纤维骨水泥(AEFC)的生长模式有助于估算死亡年龄。然而,人们对这种模式背后的结构组织仍然知之甚少。本研究分析了墨西哥现代骨骼系列中七个个体的牙骨质,旨在利用多模态成像方法揭示 AEFC 的胶原和矿物质结构。首先使用光镜、透射电子显微镜(TEM)、电子断层扫描和等离子 FIB 扫描电子显微镜(PFIB-SEM)断层扫描确定胶原纤维的组织。然后使用同步辐射小角 X 射线散射 (SAXS) 测定 T 参数(矿物颗粒之间的相关长度)、同步辐射 X 射线衍射 (XRD) 测定 L 参数(矿物晶域尺寸估算)、排列参数(晶体优先取向)和晶格参数 a 和 c,以及同步辐射 X 射线荧光测定钙、磷和锌的空间分布,对矿物特性进行了研究。结果表明,沙佩氏纤维分枝的纤维覆盖并覆盖其他胶原束,形成排列整齐的弧形结构,这些结构由相同的纤维连接,但以平行方式连接。这些平行的纤维并不是同一平面上的连续体,当它们叠加在一起时,由于胶原蛋白的双折射,会投射出 AEFC 增量线。磷灰石晶体的取向受制于胶原纤维的排列,获得的参数值和元素分布图显示这种矿物组织相对均匀。因此,矿物相的内在特征与交替的 AEFC 增量模式无关。
期刊介绍:
Journal of Structural Biology (JSB) has an open access mirror journal, the Journal of Structural Biology: X (JSBX), sharing the same aims and scope, editorial team, submission system and rigorous peer review. Since both journals share the same editorial system, you may submit your manuscript via either journal homepage. You will be prompted during submission (and revision) to choose in which to publish your article. The editors and reviewers are not aware of the choice you made until the article has been published online. JSB and JSBX publish papers dealing with the structural analysis of living material at every level of organization by all methods that lead to an understanding of biological function in terms of molecular and supermolecular structure.
Techniques covered include:
• Light microscopy including confocal microscopy
• All types of electron microscopy
• X-ray diffraction
• Nuclear magnetic resonance
• Scanning force microscopy, scanning probe microscopy, and tunneling microscopy
• Digital image processing
• Computational insights into structure