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来自 5300 年前的蒂罗尔冰人的木乃伊化 I 型胶原的纳米结构和力学特性。

Nanostructure and mechanics of mummified type I collagen from the 5300-year-old Tyrolean Iceman.

机构信息

Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstrasse 41, 80333 Munich, Germany.

出版信息

Proc Biol Sci. 2010 Aug 7;277(1692):2301-9. doi: 10.1098/rspb.2010.0377. Epub 2010 Mar 31.

Abstract

Skin protects the body from pathogens and degradation. Mummified skin in particular is extremely resistant to decomposition. External influences or the action of micro-organisms, however, can degrade the connective tissue and lay the subjacent tissue open. To determine the degree of tissue preservation in mummified human skin and, in particular, the reason for its durability, we investigated the structural integrity of its main protein, type I collagen. We extracted samples from the Neolithic glacier mummy known as 'the Iceman'. Atomic force microscopy (AFM) revealed collagen fibrils that had characteristic banding patterns of 69 +/- 5 nm periodicity. Both the microstructure and the ultrastructure of dermal collagen bundles and fibrils were largely unaltered and extremely well preserved by the natural conservation process. Raman spectra of the ancient collagen indicated that there were no significant modifications in the molecular structure. However, AFM nanoindentation measurements showed slight changes in the mechanical behaviour of the fibrils. Young's modulus of single mummified fibrils was 4.1 +/- 1.1 GPa, whereas the elasticity of recent collagen averages 3.2 +/- 1.0 GPa. The excellent preservation of the collagen indicates that dehydration owing to freeze-drying of the collagen is the main process in mummification and that the influence of the degradation processes can be addressed, even after 5300 years.

摘要

皮肤可以保护身体免受病原体和降解的侵害。特别是木乃伊化的皮肤具有极强的抗分解能力。然而,外部影响或微生物的作用会降解结缔组织,使下面的组织暴露出来。为了确定木乃伊化人体皮肤的组织保存程度,特别是其耐久性的原因,我们研究了其主要蛋白质 I 型胶原的结构完整性。我们从被称为“冰人”的新石器时代冰川木乃伊中提取了样本。原子力显微镜(AFM)显示胶原原纤维具有 69 +/- 5nm 周期性的特征带纹图案。真皮胶原纤维束和原纤维的微观结构和超微结构在很大程度上没有改变,并且被自然保存过程极好地保存了下来。古代胶原的拉曼光谱表明其分子结构没有明显的变化。然而,AFM 纳米压痕测量显示出原纤维力学性能的微小变化。单根木乃伊化原纤维的杨氏模量为 4.1 +/- 1.1GPa,而近期胶原的弹性平均为 3.2 +/- 1.0GPa。胶原的良好保存表明,由于胶原的冻干导致的脱水是木乃伊化的主要过程,即使在 5300 年后,降解过程的影响也可以得到解决。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/1b0a/2894913/25c05a587934/rspb20100377-g1.jpg

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