title: X-ray texture analysis indicates downward spinning of chitin microfibrils in tubeworm tube.
abstract: The direction of β-chitin deposition in the tube of tubeworm Lamellibrachia satsuma was investigated by texture analysis using X-ray diffraction. The β-chitin crystallite in the tube has planar orientation with the (110) plane perpendicular to the surface, and the c-axis is aligned parallel to the tube. The monoclinic unit cell of β-chitin allowed determination of the sense of c-axis from the orientation of (010) and (100) planes. This means that the reducing end of β-chitin is pointing up in the tube. This orientation can be ascribed to possible secretion mechanisms of the β-chitin microfibrils, i.e. the chitin-synthesizing enzyme complex travels unidirectionally from top to bottom when the worm body contracts in the tube.
authors.affiliation: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan; Center de Reserches sur les Macromolécules Végétales, CNRS, BP 53, 38041 Grenoble Cedex 9, France; Research Fellow of the Japan Society for the Promotion of Science, Japan. Electronic address: ayogwa@gmail.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kimura
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Masahisa
authors.initials: M
authors.lastname: Wada
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kuga
mesh_terms: D000818:Animals; D002686:Chitin / Q000378:metabolism / Q000648:ultrastructure*; D020894:Microfibrils / Q000378:metabolism / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D011077:Polychaeta / Q000378:metabolism / Q000648:ultrastructure*; D014961:X-Ray Diffraction
chemical_list: D002686:Chitin
keywords: Chitin; Lamellibrachia satsuma; Microfibril; Tubeworm; X-ray diffraction