Structural Diversity among Edwardsiellaceae Core Oligosaccharides.

The Edwardsiella genus presents five different pathogenic species: Edwardsiella tarda , E. anguillarum , E. piscicida , E. hoshinae and E. ictaluri . These species cause infections mainly in fish, but they can also infect reptiles, birds or humans. Lipopolysaccharide (endotoxin) plays an important role in the pathogenesis of these bacteria. For the first time, the chemical structure and genomics of the lipopolysaccharide (LPS) core oligosaccharides of E. piscicida , E. anguillarum , E. hoshinae and E. ictaluri were studied. The complete gene assignments for all core biosynthesis gene functions were acquired. The structure of core oligosaccharides was investigated by ¹H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The structures of E. piscicida and E. anguillarum core oligosaccharides show the presence of →3,4)-L- glycero -α-D- manno -Hep p , two terminal β-D-Glc p , →2,3,7)-L- glycero -α-D- manno -Hep p , →7)-L- glycero -α-D- manno -Hep p , terminal α-D-Glc p N, two →4)-α-D-Gal p A, → 3)-α-D-Glc p NAc, terminal β-D-Gal p and →5-substituted Kdo. E. hoshinare core oligosaccharide shows only one terminal β-D-Glc p , and instead of terminal β-D-Gal p a terminal α-D-Glc p NAc. E. ictaluri core oligosaccharide shows only one terminal β-D-Glc p , one →4)-α-D-Gal p A and do not have terminal α-D-Glc p N (see complementary figure).