Abstract
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.
