Ontogeny of an Iridescent Nanostructure Composed of Hollow Melanosomes
Ontogeny of an Iridescent Nanostructure Composed of Hollow Melanosomes
复制标题
DOI：
10.1002/jmor.20347
复制
发表时间：
2015-04-01
影响因子：
1.5
通讯作者：
Buchholz, Richard
中科院分区：
文献类型：
--
作者：
Shawkey, Matthew D.;D'Alba, Liliana;Buchholz, Richard
羽毛中的彩虹色是自然界中最明亮的颜色之一，是由周期性排列的黑色素体（含黑色素的细胞器）的相干光散射产生的。中空的黑素体是一种主要局限于鸟类的进化创新，它包含了高折射率和低折射率（分别来自黑色素和空气）的光学强大组合，能够产生比固体黑素体更明亮和更饱和的颜色。然而，尽管它们对鸟类颜色具有重要意义并具有作为光学生物材料的潜在用途，但人们对黑素体本身或其组成的纳米结构的个体发育知之甚少。我们使用光学和电子显微镜来表征野生火鸡再生羽毛中的纳米结构发展，这是一种由中空黑素体的六边形紧密排列产生的彩虹色物种。我们发现黑素体在黑素细胞中形成为固体。在发育后期，主要是在放置在发育中的微囊中之后，它们的内部溶解并留下中空的核心。这些中空的黑素体最初在触须中是无序的，但当它们被拉到触须边缘时变得紧密堆积，可能是通过包括耗尽吸引力在内的力的组合。这些数据表明，这些结构上有颜色的组织是自组装的，代表了新的发育途径。(C)2014 Wiley Periodicals，Inc.
Iridescent colors in feathers are some of the brightest in nature, and are produced by coherent light scattering from periodic arrangements of melanosomes (melanin-containing organelles). Hollow melanosomes, an evolutionary innovation largely restricted to birds, contain an optically powerful combination of high and low refractive indices (from the melanin and air, respectively) that enables production of brighter and more saturated colors than solid melanosomes. However, despite their significance to avian color and potential utility as optical biomaterials, little is known about the ontogeny of either the melanosomes themselves or the nanostructures they comprise. We used light and electron microscopy to characterize nanostructural development in regenerating feathers of wild turkeys, a species with iridescent color produced by a hexagonally close-packed array of hollow melanosomes. We found that melanosomes form as solid bodies in melanocytes. Later in development, largely after placement in developing barbules, their interiors dissolve and leave hollow cores. These now hollow melanosomes are initially disorganized in the barbule, but become close-packed as they are pulled to the edge of the barbule, likely through a combination of forces including depletion-attraction. These data suggest that these structurally colored tissues are self-assembled and represent novel pathways of development. (C) 2014 Wiley Periodicals, Inc.