title: Crystalline calcium phosphate and magnetic mineral content of Daphnia resting eggs.
abstract: Daphnia is a key crustacean zooplankton of freshwater food chains. One factor that ensures successful propagation is the Daphnia resting eggs, which are able to retain structural integrity under extreme conditions. Until recently little was known about the chemical composition, microanatomy, and physical properties of the egg itself. The current study demonstrates that the resting eggs: (1) have shells that are made up of crystalline calcium phosphate and include a honeycombed structure, and (2) contain magnetic material having properties consistent with magnetite. These properties of the resting eggs may ensure Daphnia survival in harsh environments.
authors.affiliation: Department of Integrative Bioscience and Biomedical Engineering, Waseda University, Tokyo, Japan. tamami@rtri.or.jp
authors.forename: Tamami
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Shibue
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ikeuchi
authors.forename: Masanobu
authors.initials: M
authors.lastname: Sakata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Igarashi
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Takada
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Hoshino
authors.forename: Kay
authors.initials: K
authors.lastname: Kohn
authors.forename: Hideo
authors.initials: H
authors.lastname: Namiki
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000032:analysis*; D003621:Daphnia / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D052203:Ferrosoferric Oxide; D007501:Iron / Q000032:analysis*; D008280:Magnetics; D010063:Ovum / Q000737:chemistry* / Q000000981:diagnostic imaging; D010087:Oxides / Q000032:analysis*; D011859:Radiography
chemical_list: D002130:Calcium Phosphates; D010087:Oxides; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D007501:Iron; C485829:calcium phosphate, dibasic, anhydrous; D052203:Ferrosoferric Oxide