Mesophilic Aeromonas UDP-glucose pyrophosphorylase (GalU) mutants show two types of lipopolysaccharide structures and reduced virulence.
A mutation in galU that causes the lack of O34-antigen lipopolysaccharide (LPS) in Aeromonas hydrophila strain AH-3 was identified. It was proved that A. hydrophila GalU is a UDP-glucose pyrophosphorylase responsible for synthesis of UDP-glucose from glucose 1-phosphate and UTP. The galU mutant from this strain showed two types of LPS structures, represented by two bands on LPS gels. The first one (slow-migrating band in gels) corresponds to a rough strain having the complete core, with two significant differences: it lacks the terminal galactose residue from the LPS-core and 4-amino-4-deoxyarabinose residues from phosphate groups in lipid A. The second one (fast-migrating band in gels) corresponds to a deeply truncated structure with the LPS-core restricted to one 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and three l-glycero-d-manno-heptose residues. galU mutants in several motile mesophilic Aeromonas strains from serotypes O1, O2, O11, O18, O21 and O44 were also devoid of the O-antigen LPS. The galU mutation reduced to less than 1 % the survival of these Aeromonas strains in serum, decreased the ability of these strains to adhere and reduced by 1.5 or 2 log units the virulence of Aeromonas serotype O34 strains in a septicaemia model in either fish or mice. All the changes observed in the galU mutants were rescued by the introduction of the corresponding single wild-type gene.
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Silvia
S
Vilches
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Rocío
R
Canals
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Markus
M
Wilhelms
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Maria Teresa
MT
Saló
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia.
Yuriy A
YA
Knirel
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia.
Evgeny
E
Vinogradov
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Susana
S
Merino
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
Juan M
JM
Tomás
D016980:Aeromonas hydrophila / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D000818:Animals; D001770:Blood Bactericidal Activity; D002240:Carbohydrate Sequence; D002448:Cell Adhesion / Q000235:genetics; D045744:Cell Line, Tumor; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005393:Fish Diseases / Q000382:microbiology; D005399:Fishes; D005816:Genetic Complementation Test; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000662:veterinary; D006801:Humans; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000737:chemistry*; D051379:Mice; D050296:Microbial Viability / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D019081:O Antigens / Q000096:biosynthesis; D018805:Sepsis / Q000382:microbiology; D017422:Sequence Analysis, DNA; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000235:genetics* / Q000502:physiology; D014774:Virulence
D004269:DNA, Bacterial; D008070:Lipopolysaccharides; D019081:O Antigens; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase