title: Cryo-X-ray tomography of vaccinia virus membranes and inner compartments.
abstract: Vitrified unstained purified vaccinia virus particles have been used as a test sample to evaluate the capabilities of cryo-X-ray tomography. Embedded in a thick layer of vitreous ice, the viral particles representing the mature form of the virus (MV) were visualized using full-field transmission X-ray tomography. The tomographic reconstructions reveal the viral brick-shaped characteristic structures with a size of 250x270x360nm(3). The X-ray tomograms show the presence of a clearly defined external envelope, together with an inner core surrounded by an internal envelope, including areas with clear differential density, which correlate well with those features previously described for these viral particles using electron microscopy analyses. A quantitative assessment of the resolution attained in X-ray and electron tomograms of the viral particles prepared under the same conditions yields values of 25.7 and 6.7nm half-pitch, respectively. Although the resolution of the X-ray microscope is well above the dimensions of the membranous compartments, the strong differential contrast exhibited makes it possible to precisely reveal them without any contrasting reagent within this small and complex biological sample.
authors.affiliation: Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, Madrid, Spain. jlcarras@cnb.csic.es
authors.forename: José L
authors.initials: JL
authors.lastname: Carrascosa
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Chichón
authors.forename: Eva
authors.initials: E
authors.lastname: Pereiro
authors.forename: María Josefa
authors.initials: MJ
authors.lastname: Rodríguez
authors.forename: Jose Jesús
authors.initials: JJ
authors.lastname: Fernández
authors.forename: Mariano
authors.initials: M
authors.lastname: Esteban
authors.forename: Stefan
authors.initials: S
authors.lastname: Heim
authors.forename: Peter
authors.initials: P
authors.lastname: Guttmann
authors.forename: Gerd
authors.initials: G
authors.lastname: Schneider
mesh_terms: D020285:Cryoelectron Microscopy; D014056:Tomography, X-Ray; D014616:Vaccinia virus / Q000502:physiology / Q000648:ultrastructure*