TAXONOMIC IMPLICATION OF THE APPARENT UNDETECTABILITY OF 3-DEOXY-D-MANNO-2-OCTULOSONATE (KDO) IN LIPOPOLYSACCHARIDES OF REPRESENTATIVES OF THE FAMILY VIBRIONACEAE AND THE OCCURRENCE OF KDO 4-PHOSPHATE IN THEIR INNER-CORE REGIONS

After conventional hydrolysis of lipopolysaccharides (LPSs), Kdo was not detectable by the periodate-thiobarbituric acid test in those of any member of Vibrionaceae except the genus Plesiomonas, but phosphorylated Kdo was demonstrated after strong-acid hydrolysis. Dephosphorylation, periodate oxidation, and methylation analysis of LPS preparations from 7 strains selected from all genera of Vibrionaceae, except Plesiomonas, showed that the inner-core region (unlike that in enteric Gram-negative bacteria) contains only one molecule of Kdo 4-phosphate 5-substituted with heptose, a constituent of the distal part of the core region, as in enteric bacteria. The undetectability of Kdo in LPS after conventional hydrolysis and the occurrence of phosphorylated Kdo in strong-acid hydrolysates and of Kdo 4-phosphate in the inner-core region are taxonomic characteristics of the family Vibrionaceae.