Localization of sugar-binding sites in Staphylococcus aureus using gold-labeled neoglycoprotein.

Abstract

We studied post- and pre-embedding staining of sugar-binding sites on thin sections of Staphylococcus aureus with an electron microscopic neoglycoprotein-gold technique. Although gold particles of cellobiosyl bovine serum albumin (BSA)-glycosylated BSA-, lactosyl BSA-, and melibiosyl BSA-gold did not label, heavy labeling of N-acetylglucosaminide-BSA-gold was observed in both the cell wall and the cytoplasm on Spurr-embedded thin sections of S. aureus. Inhibition of labeling with wheat germ agglutinin-biotin and N-acetylglucosaminidase indicated that the labeling was due to N-acetylglucosamine. These data suggested that molecules that bind specifically with N-acetylglucosamine occur in the cell wall and cytoplasm of S. aureus. Pre-embedding staining revealed that these molecules are abundant at the surface of the cell wall and that the abundance differs depending on the bacterial strain. An N-acetylglucosamine-specific lectin-like substance, glucosaminidase, and toxins are proposed as candidates for molecules responsible for the labeling, and the possible functional significance of the findings is discussed briefly.

Agglutination of Staphylococcus saprophyticus: a structural and cytochemical study

“…Colloidal gold particles (15 nm) were prepared according to the method of Frens [6]. Complexes of WGA-gold and neoglycoprotein-gold were prepared as we described previously [4,5]. In brief, the optimal amounts of WGA and GlcNAc-BSA for stabilization of 10 ml of colloidal gold particles were determined by the salt flocculation test [7].…”

“…Here we show that a lectin and a synthetic neoglycoprotein agglutinate S. saprophyticus. Then we applied the gold labelling technique, which we have shown previously to be useful for localization of lectins or carbohydrates [4,5], and found that these molecules are involved in agglutination of S. saprophyticus and erythrocytes.…”