title: Chromosome interior observation by focused ion beam/scanning electron microscopy (FIB/SEM) using ionic liquid technique.
abstract: Attempts to elucidate chromosome structure have long remained elusive. Electron microscopy is useful for chromosome structure research because of its high resolution and magnification. However, biological samples such as chromosomes need to be subjected to various preparation steps, including dehydration, drying, and metal/carbon coating, which may induce shrinkage and artifacts. The ionic liquid technique has recently been developed and it enables sample preparation without dehydration, drying, or coating, providing a sample that is closer to the native condition. Concurrently, focused ion beam/scanning electron microscopy (FIB/SEM) has been developed, allowing the investigation and direct analysis of chromosome interiors. In this study, we investigated chromosome interiors by FIB/SEM using plant and human chromosomes prepared by the ionic liquid technique. As a result, two types of chromosomes, with and without cavities, were visualized, both for barley and human chromosomes prepared by critical point drying. However, chromosome interiors were revealed only as a solid structure, lacking cavities, when prepared by the ionic liquid technique. Our results suggest that the existence and size of cavities depend on the preparation procedures. We conclude that combination of the ionic liquid technique and FIB/SEM is a powerful tool for chromosome study.
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Hamano
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Astari
authors.initials: A
authors.lastname: Dwiranti
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Kaneyoshi
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Fukuda
authors.affiliation: 2Laboratory of Nano Mechanics,Department of Mechanical Engineering,Graduate School of Engineering,The University of Tokyo,Hongo,Bunkyo,Tokyo 113-8685,Japan.
authors.forename: Reo
authors.initials: R
authors.lastname: Kometani
authors.affiliation: 3Department of Engineering Synthesis,Graduate School of Engineering,The University of Tokyo,Hongo,Bunkyo,Tokyo 113-8685,Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakao
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takata
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.affiliation: 4Department of Human Environmental Science,Division of Living Environment,Graduate School of Human Development and Environment,Kobe University,Tsurukabuto,Nada,Kobe 657-8501,Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Ohmido
authors.affiliation: 1Laboratory of Dynamic Cell Biology,Department of Biotechnology,Graduate School of Engineering,Osaka University,Yamadaoka,Suita,Osaka 565-0871,Japan.
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukui
mesh_terms: D002875:Chromosomes / Q000648:ultrastructure*; D001467:Hordeum; D006801:Humans; D052578:Ionic Liquids; D008855:Microscopy, Electron, Scanning / Q000379:methods*
chemical_list: D052578:Ionic Liquids