PMID:12949187

Citation	Srinivasa Rao, PS, Yamada, Y and Leung, KY (2003) A major catalase (KatB) that is required for resistance to H2O2 and phagocyte-mediated killing in Edwardsiella tarda. Microbiology (Reading, Engl.) 149:2635-44
Abstract	Edwardsiella tarda causes haemorrhagic septicaemia in fish and gastro- and extra-intestinal infections in animals including humans. Resistance to phagocyte-mediated killing is one of the virulence factors of Ed. tarda. The authors' previous studies using TnphoA transposon mutagenesis indicated that katB mutants derived from the strain PPD130/91 are at least 1.6 log higher in LD50 values than the wild-type strain. These findings suggest the involvement of catalase (KatB) in Ed. tarda pathogenesis. In this study, experiments were conducted to characterize the contribution of KatB to Ed. tarda infection. Zymographic analyses indicated that the 22 Ed. tarda strains examined expressed three different types of catalase-peroxidases (Kat1-3) based on their mobility in non-denaturing polyacrylamide gels. KatB (Kat1), the major catalase enzyme, was expressed in eight out of 22 Ed. tarda strains, and was commonly found in virulent strains except AL9379. AL9379 has a mutated katB, which has a base substitution and a deletion that translate into stop codons in the catalase gene. KatB produced by PPD130/91 was located in both periplasmic and cytoplasmic fractions and was constitutively expressed in various growth phases. Kinetics studies indicated that the catalase provided resistance to H2O2- and phagocyte-mediated killing. Infection kinetics studies of katB mutant 34 in gourami fish demonstrated its inability to survive and replicate in phagocyte-rich organs and this prevented the dissemination of infections when compared to the wild-type. Complementation of catalase mutants restored the production of catalase, and led to an increase in the resistance to H2O2- and phagocyte-mediated killing, and a decrease in LD50 values. This study has identified and characterized a major catalase gene (katB) that is required for resistance to H2O2- and phagocyte-mediated killing in Ed. tarda. The results also suggest that catalase may play a role as a virulence factor in Ed. tarda pathogenesis.
Links	PubMed
Keywords	Amino Acid Sequence; Animals; Catalase/metabolism; Drug Resistance, Bacterial; Edwardsiella tarda/drug effects; Edwardsiella tarda/genetics; Edwardsiella tarda/pathogenicity; Edwardsiella tarda/physiology; Enterobacteriaceae Infections/veterinary; Fish Diseases/microbiology; Fishes/microbiology; Hydrogen Peroxide/pharmacology; Molecular Sequence Data; Mutation; Sequence Homology, Amino Acid
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
EDWTA:Q8GB51	enables	GO:0004096: catalase activity	ECO:0000315: mutant phenotype evidence used in manual assertion		F		Seeded From UniProt	complete
EDWTA:Q8GB51		GO:0042597:	ECO:0000314:				Zymographic analysis(Fig. 5a) lane 1. This indicates that KatB of PPD130/91 secreted into the periplasmic space.	complete
EDWTA:Q8GB51		GO:0006979: response to oxidative stress	ECO:0000314:		P		Fig. 5.(b) Lane 2 on zymographic analysis.	complete
EDWTA:Q8GB51		GO:0004096: catalase activity	ECO:0000315:		F		Fig. 1 and Fig. 5	complete CACAO 2270
EDWTA:Q8GB51		GO:0009405: pathogenesis	ECO:0000315:		P		Fig. 7	complete CACAO 2273
EDWTA:Q8GB51	involved_in	GO:0009405: pathogenesis	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
EDWTA:Q0PD68		GO:0004096 : catalase activity	ECO:0000315:		F		Fig. 1b	complete
EDWTA:Q0PD68		GO:0042542 : response to hydrogen peroxide	ECO:0000315:		P		Fig. 6	complete

References

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