Silk is produced by a variety of insects, but only silk made by terrestrial arthropods has been examined in detail. To fill the gap, this study was designed to understand the silk spinning system of aquatic insect. The larvae of caddis flies, Hydatophylax nigrovittatus produce silk through a pair of labial silk glands and use raw silk to protect themselves in the aquatic environment. The result of this study clearly shows that although silk fibers are made under aquatic conditions, the cellular silk production system is quite similar to that of terrestrial arthropods. Typically, silk production in caddisworm has been achieved by two independent processes in the silk glands. This includes the synthesis of silk fibroin in the posterior region, the production of adhesive glycoproteins in the anterior region, which are ultimately accumulated into functional silk dope and converted to a silk ribbon coated with gluey substances. At the cellular level, each substance of fibroin and glycoprotein is specifically synthesized at different locations, and then transported from the rough ER to the Golgi apparatus as transport vesicles, respectively. Thereafter, the secretory vesicles gradually increase in size by vesicular fusion, forming larger secretory granules containing specific proteins. It was found that these granules eventually migrate to the apical membrane and are exocytosed into the lumen by a mechanism of merocrine secretion.

中文翻译：

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石蚕丝纺系统的精细结构，Hydatophylax nigrovittatus（Trichoptera：Limnephilidae）

丝绸是由多种昆虫生产的，但只有陆生节肢动物生产的丝绸已被详细研究过。为了填补这一空白，本研究旨在了解水生昆虫的丝纺系统。石蚕的幼虫Hydatophylax nigrovittatus通过一对唇丝腺产丝，在水生环境中利用生丝保护自己。这项研究的结果清楚地表明，虽然丝纤维是在水生条件下制造的，但细胞丝生产系统与陆生节肢动物的生产系统非常相似。通常，通过丝腺中的两个独立过程实现了caddisworm 中的丝生产。这包括在后区合成丝素蛋白，在前区产生粘着糖蛋白，最终积累成功能性丝胶，并转化为涂有胶状物质的丝带。在细胞水平上，丝心蛋白和糖蛋白的每种物质在不同位置特异性合成，然后分别作为转运囊泡从粗糙的内质网转运到高尔基体。此后，分泌囊泡通过囊泡融合逐渐变大，形成更大的含有特定蛋白质的分泌颗粒。发现这些颗粒最终迁移到顶膜并通过分分泌分泌的机制被胞吐到管腔中。然后分别作为运输囊泡从粗糙的内质网运输到高尔基体。此后，分泌囊泡通过囊泡融合逐渐变大，形成更大的含有特定蛋白质的分泌颗粒。发现这些颗粒最终迁移到顶膜并通过分分泌分泌的机制被胞吐到管腔中。然后分别作为运输囊泡从粗糙的内质网运输到高尔基体。此后，分泌囊泡通过囊泡融合逐渐变大，形成更大的含有特定蛋白质的分泌颗粒。发现这些颗粒最终迁移到顶膜并通过分分泌分泌的机制被胞吐到管腔中。