The structure of people's hair
The structure of people's hair
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DOI：
10.7717/peerj.619
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发表时间：
2014-10-14
期刊：
影响因子：
2.7
通讯作者：
Rheinstaedter, Maikel C.
中科院分区：
文献类型：
--
作者：
Yang, Fei-Chi;Zhang, Yuchen;Rheinstaedter, Maikel C.
毛发是主要由蛋白质特别是角蛋白组成的丝状生物材料。人类头发的结构是众所周知的：髓质是一个松散的，无序的区域，靠近头发的中心，被皮质包围，其中包含了大部分的纤维物质，主要由角蛋白和结构脂质组成。皮质被角质层包围，角质层是一层死亡的，重叠的细胞在头发周围形成保护层。相应的结构已被广泛研究，使用各种不同的技术，如光，电子和原子力显微镜，以及X射线衍射。我们感兴趣的问题有多少分子头发结构不同的人，男性和女性的头发，头发的不同外观，如颜色和波纹。我们在研究中包括了父母和孩子、同卵双胞胎和异卵双胞胎的头发，看看基因相似的头发是否会显示出相似的结构特征。头发样本的分子结构是用高分辨率X射线衍射研究的，它涵盖了从分子到二级结构组织的长度尺度。由于α-螺旋角蛋白，中间角蛋白丝在皮层和从细胞膜复合物中的脂质层的卷曲螺旋相的信号中观察到的所有个人的标本，具有非常小的偏差。尽管本研究纳入的个体数量相对较少（12），但仍可以得出一些结论。虽然在所有个体中观察到一般特征，并且相应的分子结构几乎相同，但在一些标本中观察到额外的信号，并分配给细胞膜复合物中不同类型的脂质。遗传学似乎在这一组成中发挥了作用，因为在父亲和女儿以及同卵双胞胎的头发中观察到了相同的图案，但是，异卵双胞胎却没有。这些特征的鉴定和表征是检测毛发分子结构异常的重要一步，作为某些疾病的潜在诊断工具。
Hair is a filamentous biomaterial consisting mainly of proteins in particular keratin. The structure of human hair is well known: the medulla is a loosely packed, disordered region near the centre of the hair surrounded by the cortex, which contains the major part of the fibre mass, mainly consisting of keratin proteins and structural lipids. The cortex is surrounded by the cuticle, a layer of dead, overlapping cells forming a protective layer around the hair. The corresponding structures have been studied extensively using a variety of different techniques, such as light, electron and atomic force microscopes, and also X-ray diffraction. We were interested in the question how much the molecular hair structure differs from person to person, between male and female hair, hair of different appearances such as colour and waviness. We included hair from parent and child, identical and fraternal twins in the study to see if genetically similar hair would show similar structural features.The molecular structure of the hair samples was studied using high-resolution X-ray diffraction, which covers length scales from molecules up to the organization of secondary structures. Signals due to the coiled-coil phase of alpha-helical keratin proteins, intermediate keratin filaments in the cortex and from the lipid layers in the cell membrane complex were observed in the specimen of all individuals, with very small deviations. Despite the relatively small number of individuals (12) included in this study, some conclusions can be drawn. While the general features were observed in all individuals and the corresponding molecular structures were almost identical, additional signals were observed in some specimen and assigned to different types of lipids in the cell membrane complex. Genetics seem to play a role in this composition as identical patterns were observed in hair from father and daughter and identical twins, however, not for fraternal twins. Identification and characterization of these features is an important step towards the detection of abnormalities in the molecular structure of hair as a potential diagnostic tool for certain diseases.