Vibrio JEuuiulis, a species of micro-organism that causes diarrhoea and other symptoms similar to, although not as severe as, those caused by V. cholerue O-l (Asian cholera) has been divided into 18 0-antigenic types'. A marine vibro, V.flwiulis 181-86 Kobe, which does not belong to any of these types, possesses' an 0-antigenic factor in common with V. cholerae O-l. Its lipopolysaccharide (LPS) also contains 4-amino-4,6dideoxy-o-mannose ("perosamine"), which is the main, possibly the only, sugar component of the I? cholerae 0-antigen3. The structure of the O-antigen polysaccharide from another strain, V.fluuiulis OKA-82-708, has been determined4, and these seem to be the only chemical studies of LPS from V.~uoialis. We now report studies of the O-antigen polysaccharide of V. Jluuiulis AA-18239, a clinical strain isolated at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B), Dhaka.
The LPS was isolated from killed, freeze-dried cells of I'. flwiufis AA-18239 by extraction with phenol-water5 and purified by ultracentrifugation. The polysaccharide (PS) was prepared from the LPS by hydrolysis with aqueous 1% acetic acid at loo", and was eluted from Bio-Gel P-10 shortly after the void volume.
The PS had [c$, + 107" (c 0.3, water) and, on hydrolysis with acid, yielded D-ribose, D-glucose, 2-amino-2-deoxy-D-galactose, and two heptoses in the molar proportions 3.0: 1:6.2:0.5:0.3. The alditol acetates of the heptoses had the same retention times in g.1.c. as those of L-glycero-rwmmnoand D-glycero-D-munno-heptose, respectively. The absolute configurations of the sugars were determined as devised by Gerwig et al.'. Methylation analysis of the PS gave 3,5-di-0-methyl-o-ribose, 2,3,4-tri-O-methyl-D-glucose, 2,3,4,6-tetra-O-methyl-D-glucose, and 2-deoxy-3,6-di-O-methyl-ZN-methylacetamido-D-galactose in the molar proportions 3.5:2.0:1:10.5. * Dedicated to Professor Leslie Hough in the year of his 65th birthday.