title: Dual Cellular Supporters: Multi-Layer Glial Wrapping and the Penetrative Matrix Specialized in Deep-Sea Hydrothermal Vent Endemic Scale-Worms.
abstract: Hydrothermal vent organisms undergo extreme environments that may require unique innovations. The present study reports a distinct case of cellular supportive systems in the nervous systems of a scale-worm, Branchinotogluma japonica, endemic to deep-sea hydrothermal vents. We found two organizations in the tissues of these animals. First, multi-layers of glia ensheath the ventral cell bodies of the brain and ventral nerve cord, in a manner similar to that of myelin or lamellar ensheathments. Second, matrices of numerous penetrative fibers, or tonofilaments, composed of bundles of ca. 20-nm fibers, are directly connected with the basal parts of epidermal cuticles and run into the diffuse intercellular spaces of the brain neuropils and peripheral nerves. Both types of tissue might be mechanical supportive structures for the neuronal cell bodies. In addition, as a glial function, the multi-layer membranes and the epithelial support cells may be required for physicochemical homeostatic regulation to filter toxic heavy metals and for inhibiting breakdown of glial membrane integrity under strong oxidative stress imposed by hypoxia in the hydrothermal vent environment. Similar functions are known in the well-studied cases of the blood-brain barrier in mammalian brains, including in human stroke.
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan; sushigeno@jamstec.go.jp.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Shigeno
authors.affiliation: Marine Works Japan LTD., 3-54-1 Oppamahigashi, Yokosuka 237-0063, Japan; and.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tame
authors.affiliation: Marine Works Japan LTD., 3-54-1 Oppamahigashi, Yokosuka 237-0063, Japan; and.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Uematsu
authors.affiliation: Faculty of Agriculture, University of Miyazaki, Gakuen-kibanadai-nishi-1-1, Miyazaki 889-2192, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Miura
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan;
authors.forename: Shinji
authors.initials: S
authors.lastname: Tsuchida
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan;
authors.forename: Katsunori
authors.initials: K
authors.lastname: Fujikura
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000648:ultrastructure; D060086:Hydrothermal Vents; D007382:Intermediate Filaments / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009457:Neuroglia / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000648:ultrastructure; D011077:Polychaeta / Q000502:physiology / Q000648:ultrastructure*