Cohen E
Eur J Cell Biol. 1982 Feb;26(2):289-94.
Chitin microfibril synthesis in Tribolium castaneum chitin synthetase (CS) assays results in the formation of a considerable precipitate. Such precipitate does not appear in the absence of the CS substrate (uridine diphospho N-acetyl-D-glucosamine) or in the presence of polyoxin-D, a potent CS inhibitor. Diflubenzuron which blocks in vivo chitin synthesis in insects has no effect on the precipitate formation at a relatively high concentration (3 x 10(-4) M). Electron microscopic examination of the CS product reveals a network of long, parallel oriented microfibrils. The microfibrils vary in thickness from 10 to 80 nm. Thinner elements merge to form larger and thicker microfibrils which are packed in distinct bundles. Particles associated with the microfibrils are largely spheroidal and range from about 50 to 250 nm in diameter. Coiled fibroid structures enclosed inside particles were observed. Similar coiled structures or extended fibroids attached to the outside (shell) of particles were also found. The nature of the particles and their possible role in chitin synthesis and fibrillogenesis in insects are discussed.
在赤拟谷盗几丁质合成酶（CS）检测中，几丁质微纤丝的合成会产生大量沉淀。在没有CS底物（尿苷二磷酸N - 乙酰 - D - 葡糖胺）的情况下，或者在强效CS抑制剂多氧霉素 - D存在时，不会出现这种沉淀。在昆虫体内阻断几丁质合成的氟虫脲，在相对高浓度（3×10⁻⁴ M）时对沉淀形成没有影响。对CS产物进行电子显微镜检查发现，有一个由长的、平行排列的微纤丝组成的网络。微纤丝的厚度在10到80纳米之间变化。较细的微纤丝合并形成更大、更粗的微纤丝，这些微纤丝被包裹成不同的束状。与微纤丝相关的颗粒大多呈球形，直径约为50到250纳米。观察到颗粒内部有盘绕的纤维状结构。还发现了附着在颗粒外部（外壳）的类似盘绕结构或延伸的纤维。本文讨论了颗粒的性质及其在昆虫几丁质合成和纤维形成中的可能作用。
