title: Rapid contrast evaluation method based on affinity beads and backscattered electron imaging for the screening of electron stains.
abstract: Uranyl salts are toxic and radioactive; therefore, several studies have been conducted to screen for substitutes of electron stains. In this regard, the contrast evaluation process is time consuming and the results obtained are inconsistent. In this study, we developed a novel contrast evaluation method using affinity beads and a backscattered electron image (BSEI), obtained using scanning electron microscopy. The contrast ratios of BSEI in each electron stain treatment were correlated with those of transmission electron microscopic images. The affinity beads bound to cell components independently. Protein and DNA samples were enhanced by image contrast treated with electron stains; however, this was not observed for sugars. Protein-conjugated beads showed an additive effect of image contrast when double-stained with lead. However, additive effect of double staining was not observed in DNA-conjugated beads. The varying chemical properties of oligopeptides showed differences in image contrast when treated with each electron stain. This BSEI-based evaluation method not only enables screening for alternate electron stains, but also helps analyze the underlying mechanisms of electron staining of cellular structures.
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kaku
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Muranaka
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan.
authors.forename: Pyoyun
authors.initials: P
authors.lastname: Park
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan ikeken@phoenix.kobe-u.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ikeda
mesh_terms: D000345:Affinity Labels / Q000378:metabolism; D000818:Animals; D002241:Carbohydrates / Q000737:chemistry; D003287:Contrast Media / Q000378:metabolism; D004247:DNA / Q000648:ultrastructure; D004583:Electrons; D022781:Hepatocytes / Q000648:ultrastructure; D008055:Lipids / Q000737:chemistry; D019216:Metals, Heavy / Q000378:metabolism; D051379:Mice; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D008863:Microspheres; D011506:Proteins / Q000648:ultrastructure
chemical_list: D000345:Affinity Labels; D002241:Carbohydrates; D003287:Contrast Media; D008055:Lipids; D019216:Metals, Heavy; D011506:Proteins; D004247:DNA
keywords: backscattered electron image; contrast; non-isotope; samarium chloride; scanning electron microscope; uranyl acetate