title: Role of Gne and GalE in the virulence of Aeromonas hydrophila serotype O34.
abstract: The mesophilic Aeromonas hydrophila AH-3 (serotype O34) strain shows two different UDP-hexose epimerases in its genome: GalE (EC 3.1.5.2) and Gne (EC 3.1.5.7). Similar homologues were detected in the different mesophilic Aeromonas strains tested. GalE shows only UDP-galactose 4-epimerase activity, while Gne is able to perform a dual activity (mainly UDP-N-acetyl galactosamine 4-epimerase and also UDP-galactose 4-epimerase). We studied the activities in vitro of both epimerases and also in vivo through the lipopolysaccharide (LPS) structure of A. hydrophila gne mutants, A. hydrophila galE mutants, A. hydrophila galE-gne double mutants, and independently complemented mutants with both genes. Furthermore, the enzymatic activity in vivo, which renders different LPS structures on the mentioned A. hydrophila mutant strains or the complemented mutants, allowed us to confirm a clear relationship between the virulence of these strains and the presence/absence of the O34 antigen LPS.
authors.affiliation: Departamento Microbiología, Facultad Biología, Universidad Barcelona, Diagonal 645, 08071 Barcelona, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Canals
authors.forename: Natalia
authors.initials: N
authors.lastname: Jiménez
authors.forename: Silvia
authors.initials: S
authors.lastname: Vilches
authors.forename: Miguel
authors.initials: M
authors.lastname: Regué
authors.forename: Susana
authors.initials: S
authors.lastname: Merino
authors.forename: Juan M
authors.initials: JM
authors.lastname: Tomás
mesh_terms: D016980:Aeromonas hydrophila / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D000595:Amino Acid Sequence; D000818:Animals; D002238:Carbohydrate Epimerases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002240:Carbohydrate Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D023061:Gene Order; D005816:Genetic Complementation Test; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D019081:O Antigens / Q000737:chemistry / Q000378:metabolism; D017686:Oncorhynchus mykiss; D010957:Plasmids; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014534:UDPglucose 4-Epimerase / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014774:Virulence / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D008070:Lipopolysaccharides; D019081:O Antigens; D002238:Carbohydrate Epimerases; D014534:UDPglucose 4-Epimerase