Some observations on the structure and function of the spinning apparatus in the silkworm Bombyx mori

Tetsuo Asakura, Kosuke Umemura, Yasumoto Nakazawa, Haruko Hirose, James Higham, David Knight

    Research output: Contribution to journalArticle

    Abstract

    Silkworm silk has outstanding mechanical properties despite being spun at room temperature and from aqueous solution. Although it has been proposed that fiber formation is mainly induced by shearing and extensional flow in the spinneret, the detailed structure and function of the spinning apparatus of Bombyx mori silkworms are still not fully elucidated. In this paper we describe three aspects of the functional microanatomy of the spinning apparatus: changes in the diameter of the silk gland duct with distance along the duct, how the birefringence of the fibroin changes as it flows down the duct, and the detailed three-dimensional structure of the silk press and related structures. The existence of a double escaped nematic liquid crystal texture in the fibroin in a region of the duct is described. After this region the birefringence suddenly disappeared until the start of an internal draw down taper which commenced just before the silk press. In the internal draw down taper the birefringence increased dramatically to an asymptotic value as a thread was drawn from the fibroin gel. The structure of the silk press suggests that it acts as a restriction die whose diameter can be regulated.

    Original languageEnglish (US)
    Pages (from-to)175-181
    Number of pages7
    JournalBiomacromolecules
    Volume8
    Issue number1
    DOIs
    StatePublished - Jan 2007

    ASJC Scopus subject areas

    • Bioengineering
    • Biomaterials
    • Polymers and Plastics
    • Materials Chemistry

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  • Cite this

    Asakura, T., Umemura, K., Nakazawa, Y., Hirose, H., Higham, J., & Knight, D. (2007). Some observations on the structure and function of the spinning apparatus in the silkworm Bombyx mori. Biomacromolecules, 8(1), 175-181. https://doi.org/10.1021/bm060874z