Neville A C, Parry D A, Woodhead-Galloway J
J Cell Sci. 1976 Jun;21(1):73-82. doi: 10.1242/jcs.21.1.73.
Electron microscopy has revealed that chitin from a representative selection of insect orders (plus one crustacean and one arachnid) is localized in crystallites about 2.8 nm across. Furthermore, these crystallites are arranged on an hexagonal or pseudo-hexagonal lattice, the lateral order of which varies considerably. The lattice becomes secondarily reoriented during cuticle expansion following an ecdysis. The size of the 'unit cell' has been measured both by optical diffraction and direct measurements of the micrographs, permitting an estimate of the chitin and resilin content for locust rubberlike cuticle. The number of poly-N-acetyl-glucosamine chains per sheet and sheets per crystallite can be estimated from the physical dimensions of the crystallite. Each crystallite is unlikely to comprise more than 3 sheets and 6 chains per sheet. The calculated and measured density of alpha-chitin can be shown to be in close agreement.
电子显微镜检查显示，从具有代表性的多种昆虫目（外加一种甲壳类动物和一种蛛形纲动物）中提取的几丁质位于直径约2.8纳米的微晶中。此外，这些微晶排列在六边形或准六边形晶格上，其横向排列顺序差异很大。在蜕皮后的角质层扩张过程中，晶格会发生二次重新定向。通过光学衍射和对显微照片的直接测量，已测量出“晶胞”的大小，从而能够估算出蝗虫类橡胶状角质层中的几丁质和弹性蛋白含量。根据微晶的物理尺寸，可以估算出每片的聚-N-乙酰葡糖胺链数以及每个微晶中的片层数。每个微晶不太可能包含超过3片，且每片不超过6条链。计算得出的α-几丁质密度与测量值显示出密切的一致性。
