Zhang Yan, Zhao Dongchao, Meng Zhu, Dong Zhaoming, Lin Ying, Chen Shiyi, Xia Qingyou, Zhao Ping
State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China.
Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China.
J Insect Sci. 2017 Sep 1;17(5). doi: 10.1093/jisesa/iex069.
The silk of silkworm consists of fibroin fiber coated by sericins. In addition, some nonprotein components were also identified in the sericin fraction. The presence of nonprotein components in the silk has not been well explained. In the present study, methods based on gas chromatography-mass spectrometry were used to identify the metabolites in the cocoon silk from a wild silkworm and two domestic silkworm strains. In total, 45 metabolites were in the cocoon silk, including organic acids, fatty acids, carbohydrates, amino acids, and hydrocarbons. Comparative analyses revealed that 17 metabolites were significant more in the wild silkworm cocoon than in the domestic silkworm cocoon, including three organic acids, three fatty acids, three aldoses, four sugar alcohols, three hydrocarbons, and pyridine. Of them, citric acid in the wild silkworm cocoon is more than 40 times that in the domestic silkworm cocoon, which may have protective value against microbes. The carbohydrate, lipid, and the long-chain hydrocarbons may act as water repellent to make the pupa survive longer in the dry environment. Many metabolites in the cocoon silk may play roles to improve the silk resistance. Lots of nonprotein components were identified in the silk for the first time, providing useful data for understanding the biological function of the cocoon silk.
蚕茧丝由丝素纤维和包覆在其外的丝胶组成。此外，在丝胶部分还鉴定出了一些非蛋白质成分。蚕丝中存在非蛋白质成分的现象尚未得到很好的解释。在本研究中，采用基于气相色谱 - 质谱联用的方法来鉴定一种野生蚕和两种家蚕品系茧丝中的代谢物。茧丝中总共含有45种代谢物，包括有机酸、脂肪酸、碳水化合物、氨基酸和碳氢化合物。比较分析表明，野生蚕茧中的17种代谢物显著多于家蚕茧，其中包括三种有机酸、三种脂肪酸、三种醛糖、四种糖醇、三种碳氢化合物和吡啶。其中，野生蚕茧中的柠檬酸含量是家蚕茧的40多倍，这可能对抵御微生物具有保护作用。碳水化合物、脂质和长链碳氢化合物可能起到防水作用，使蛹在干燥环境中存活更长时间。茧丝中的许多代谢物可能在提高蚕丝抗性方面发挥作用。首次在蚕丝中鉴定出大量非蛋白质成分，为理解茧丝的生物学功能提供了有用的数据。
