LOCALIZATION OF SUGAR-BINDING SITES IN STAPHYLOCOCCUS-AUREUS USING GOLD-LABELED NEOGLYCOPROTEIN

We studied post- and pre-embedding staining of sugar-binding sites on thin sections of Staphylococcus aureus with an electron microscopic ne oglycoprotein-gold technique. Although gold particles of cellobiosyl b ovine serum albumin (BSA)-glycosylated BSA-, lactosyl BSA-, and melibi osyl BSA-gold did not label, heavy labeling of N-acetylglucosaminide-B SA-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 mol ecules that bind specifically with N-acetylglucosamine occur in the ce ll wall and cytoplasm of S. aureus. Preembedding staining revealed tha t these molecules are abundant at the surface of the cell, mall and th at the abundance differs depending on the bacterial strain. An N-acety lglucosamine-specific lectin-like substance, glucosaminidase, and toxi ns are proposed as candidates for molecules responsible for the labeli ng, and the possible functional significance of the findings is discus sed briefly.