STRUCTURES OF POLYMERIC PRODUCTS ISOLATED FROM THE LIPOPOLYSACCHARIDES OF REFERENCE STRAINS FOR ACINETOBACTER-BAUMANNII O23 AND O-12

A polysaccharide containing D-galactose (Gal), 2-acetamido-2-deoxy-D-g alactose (GalNAc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and 3-deoxy -3-(D-3-hydroxybutyramido)-D-quinovose (Qui3NR) was isolated from lipo polysaccharide (LPS) obtained from cells walls of the reference strain for Acinetobacter baumannii O23. By means of NMR studies, methylation analysis, and chemical degradations, the repeating unit of the polyme r was identified as a branched pentasaccharide with the structure 1. T he same polymer was apparently also present in LPS of the reference st rain for serogroup O12, together with a second polymer based on a bran ched tetrasaccharide with the structure 2. This second polymer has pre viously been isolated as the O16 antigen of A. baumannii [Haseley, S. R., Diggle, H. J. & Wilkinson, S. G. (1996) Carbohydr. Res. 293, 259-2 65] and is probably present as a minor component of the LPS of A. baum annii O11 [Haseley, S. R. & Wilkinson, S. G. (1996) Eur. J. Biochem. 2 37, 266-271]. [GRAPHICS] during the complex process of spermatozoa pro duction and maturation in the testis and epididymis.