Postembedding staining of Brunner's gland with lectin-ferritin conjugates

Postembedding staining of intracellular carbohydrates of rat Brunner's gland cells embedded in Epon and acrylamide was carried out with Ricinus communis agglutinin-ferritin, concanavalin A-ferritin, and wheat germ agglutinin-ferritin conjugates. Th Golgi vacuoles and mucous granules were stained with these conjugates. In each staining, the tissues embedded in acrylamide were stained more strongly than those embedded in Epon. The staining intensity of wheat germ agglutinin-ferritin was the strongest among the three conjugates and the staining intensity of Ricinus communis agglutinin-ferritin was stronger than that of concanavalin A-ferritin in both embedding methods. Free ferritin showed almost no binding to these structures and staining with the conjugates was inhibited by the addition of appropriate competitive sugars to the staining solutions. Osmium-postfixed tissues were not stained well with the conjugates. Washing of the sections with bovine serum albumin solution after staining was an essential step in the present method to reduce the nonspecific adsorption of the conjugates. The present method was very simple and had good reproducibility.