Characterization of exopotysaccharjde isolated from Prevotella nigrescens

Abstract

Previous studies have shown that exopolysaccharjde (EPS) from Prevotella intermedia is related to the jnvasjveness of bacteria. In this study, we attempted to purify EPS derived from Prevotella nigrescens and compared it with that from P. intermedia. We also isolated an EPS^- strain from the EPS^+ strain by treatment with ethidium bromide, and examined the pheno- and genotypic characteristics of these strains. Purified EPS was primarily carbohydrate consisting of mannose, glucose, galactose, arabjnose and xylose. However, the ratio of mannose was greater in the EPS from P. nigrescens than in that from P. intermedia. The plasmid bands and enzymatic activities were the same for both EPS^- and EPS^+. The hemagglutinating activity of the EPS^- strain was greater, indicating that EPS tends to interfere with hemagglutination than mediate it.