IBIS version 3: an OSF/Motif-based interface for IBIS--integrated biological imaging system.

IBIS is a set of computer programs dedicated to the processing of electron micrographs, mainly for structural analysis of biological macromolecules. We present IBIS version 3, a UNIX/OSF/Motif 1.2-based package which carries out and provides visual display of the many operations essential to image analysis.

IBIS integrated biological imaging system: electron micrograph image-processing software running on Unix workstations.

'IBIS' is a set of computer programs concerned with the processing of electron micrographs, with particular emphasis on the requirements for structural analyses of biological macromolecules. The software is written in FORTRAN 77 and runs on Unix workstations. A description of the various functions and the implementation mode is given.

Characterization of a ferritin isolated from the midgut epithelial cells of a homopteran insect, Philaenus spumarius L.

Crystalline accumulations of ferritin-like particles are present within the cytoplasma and the nucleus in midgut epithelial cells of the homopteran Philaenus spumarius. A structural study at the electron microscope level reveals that these particles have the morphological characteristics of the ferritin molecule: crystals have a face-centered cubic structure with a lattice parameter of 14 +/- 1 nm; negatively stained isolated particles have the appearance of ferritin; on rotary-shadowed particles 3 axes of symmetry are clearly seen; image processing performed on selected molecules demonstrates a 4-fold symmetry. A semiquantitative electron microprobe analysis effected on aggregates of microcrystals in thin sections reveals a high atomic ratio Fe/P.

Image processing of electron micrographs of human alpha 2-macroglobulin half-molecules induced by Cd2+.

Human alpha 2-macroglobulin is a tetrameric plasma inhibitor of proteinases. Its dissociation by Cd2+ gives functional dimers. Electron microscopy of negatively stained dimers shows their round-ended cylindrical shape with furrows delimiting 3 main stain-excluding domains.