Postembedding staining methods using ruthenium red (RR) incombination with tungstate (TT) (phospho-or silicotungstic acid) (RR-TT) were tested for the effective visualization of acidic glycoconjugates in electron microscopy. Tissue blocks of trachea and colon from adult male Wistar rats were fixed in phosphatebuffered glutaraldehyde-paraformaldehyde solution and embedded in LR-White. Ultrathin sections were cut, stained first with RR (pH 2.5) and then incubated in TT. In the tissues examined, all the ultrastructures containing acidic glycoconjugates exhibited apparent positive reaction for RR-TT. If stained singly with RR or TT under the same staining conditions, most of these ultrastructures failed to give any distinct electron densities. In all the acidic glycoconjugate-containing ultrastructures tested, digestion with testicular hyaluronidase greatly diminished or abolished their RR-TT reactions. In view of these results, the present RR-TT methods can be regarded as a useful technique for the efficient visualization of acidic glycoconjugates in electron microscopy.In different mammalian species, it has been well known that intra-and extracellular ultrastructures contain acidic glycoconjugates which play an important role in living organisms. To visualize such acidic glycoconjugates, numerous attempts have been made using electron microscopic histochemical methods with basic dyes [ruthenium red (2, 3, 14), alcian bule (1, 25), cuprolinic blue (21, 26), high and low iron diamine (20,22,24)] and colloidal ions [dialyzed iron, (7, 12, 29), colloidal iron (27), colloidal thorium (18)]. The majority of these staining procedures employed staining reagents applied to tissue specimens at preembedding stages of tissue preparations, and such procedures suffered from the limited penetration of staining reagents into cells. To overcome such weaknesses, a series of staining reagents were applied to tissue specimens at postembedding stages of tissue preparations (4,6,9,15,18,30). At first glance, these postembedding staining methods appeared to be satisfactory for visualizing acidic glycoconjugate-containing ultrastructures in electron microscopy. If closely examined, however, these acidic glycoconjugate-containing ultrastructures were found to be contaminated with varying degrees of non-specific background stain- 165 Correspondence to:
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.