Complete Characterization of the O-Antigen from the LPS of Aeromonas bivalvium

• Published in: International journal of molecular sciences 2022-01, Vol.23 (3), p.1204
• Main Authors: Di Guida, Rossella, Casillo, Angela, Tomás, Juan M, Merino, Susana, Corsaro, Maria Michela
• Format: Article
• Language: English
• Subjects: Aeromonas; Aeromonas - metabolism; Analytical chemistry; Antigens; Aquatic environment; Bacteria; Biosynthesis; Carbohydrate Sequence; Carbon; Centrifugation; Chromatography; Cockles; Drinking water; Fatty acids; Glucose; Gram-negative bacteria; Hydrolysis; Immunology; Infections; Lipid A; Lipid A - chemistry; Lipids; lipopolysaccharide; Lipopolysaccharides; Lipopolysaccharides - chemistry; Lipopolysaccharides - metabolism; Magnetic resonance spectroscopy; Meat; Mineral water; NMR; NMR spectroscopy; Nuclear magnetic resonance; O Antigens - chemistry; O-antigen; Oligosaccharides; Opportunist infection; Pathogenicity; Phagocytosis; Polymers; Polymers - chemistry; Polysaccharides; Seafood; structure elucidation; Vertebrates; WaaE gene
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23031204

species are found in the aquatic environment, drinking water, bottled mineral water, and different types of foods, such as meat, fish, seafood, or vegetables. Some of these species are primary or opportunistic pathogens for invertebrates and vertebrates, including humans. Among the pathogenic factors associated with these species, there are the lipopolysaccharides (LPSs). LPSs are the major components of the external leaflet of Gram-negative bacterial outer membrane. LPS is a glycoconjugate, generally composed of three portions: lipid A, core oligosaccharide, and O-specific polysaccharide or O-antigen. The latter, which may be present (smooth LPS) or not (rough LPS), is the most exposed part of the LPS and is involved in the pathogenicity by protecting infecting bacteria from serum complement killing and phagocytosis. The O-antigen is a polymer of repeating oligosaccharide units with high structural variability, particularly the terminal sugar, that confers the immunological specificity to the O-antigen. In this study, we established the structure of the O-chain repeating unit of the LPS from strain 868 E (=CECT 7113 = LMG 23376 ), a mesophilic bacterium isolated from cockles ( sp.) and obtained from a retail market in Barcelona (Spain), whose biosynthesis core LPS cluster does not contain the gene as most of species. After mild acid hydrolysis, the lipid A was removed by centrifugation and the obtained polysaccharide was fully characterized by chemical analysis and NMR spectroscopy. The polymer consists of a heptasaccharide repeating unit containing D-GalNAc, L-Rha, D-GlcNAc, and D-FucNAc residues.