Superoxide dismutase and catalase in Photobacterium damselae subsp. piscicida and their roles in resistance to reactive oxygen species

Abstract

Photobacterium damselae subsp. piscicida (formerly Pasteurella pisckida) is the causative agent of pasteurellosis or pseudotuberculosis in warm water marine fish. Enzymes which neutralize reactive oxygen species, produced during aerobic metabolism or during respiratory burst in fish macrophages, are important virulence factors in many pathogens. This study characterizes a periplasmic superoxide dismutase (SOD) and a cytoplasmic catalase in P. damselae. Purification and partial amino-terminal sequencing confirmed the SOD to be iron-cofactored, with a high degree of homology to other bacterial FeSODs. The SOD was common to all strains analysed in terms of type, location and activity, whilst the catalase varied in activity between strains. The catalase was constitutively expressed, but the SOD appeared to be repressed under low oxygen conditions. In spite of the presence of a periplasmic SOD, P. damselae was susceptible to killing by exogenous superoxide anion generated in a cellfree system. Addition of exogenous SOD to this system did not abolish the bactericidal eft: ect; however, addition of catalase was protective. These results suggest that lack of periplasmic catalase may be implicated in susceptiblity t o killing by reactive oxygen species.

Rubrerythrin and Rubredoxin Oxidoreductase inDesulfovibrio vulgaris: a Novel Oxidative Stress Protection System

“…We have found no data addressing the localizations of SODs in other sulfate-reducing bacteria. A few other periplasmic Fe/Mn-SODs have been reported, but only from aerobes (4,16,37).…”

“…Rbr is a homodimeric protein that contains both a rubredoxin-like [Fe(SCys) 4 ] center and a nonsulfur, oxo-bridged diiron site (14). The best-characterized Rbr is that from the anaerobic sulfate-reducing bacterium D. vulgaris (strain Hildenborough).…”

“…Center I contains a distorted rubredoxin-type [Fe(SCys) 4 ] coordination sphere and is presumably an electron transfer center. Center II contains a unique [Fe(NHis) 4 (SCys)] site that is rapidly oxidized by O 2 Ϫ and is, therefore, the likely site of superoxide reduction (26).…”

“…Center I contains a distorted rubredoxin-type [Fe(SCys) 4 ] coordination sphere and is presumably an electron transfer center. Center II contains a unique [Fe(NHis) 4 (SCys)] site that is rapidly oxidized by O 2 Ϫ and is, therefore, the likely site of superoxide reduction (26). The only iron site in a blue nonheme iron protein, neelaredoxin (Nlr) from Desulfovibrio gigas (10), closely resembles that of Rbo center II (11).…”

Contribution of Catalase and Superoxide Dismutase to the Intracellular Survival of Clinical Isolates of Staphylococcus aureus in Murine Macrophages

“…Suspensions were sonicated on ice at 8 lm for 90 s (six 15 s bursts with 15 s cooling periods) and then centrifuged at 16 000 9g for 45 min at 4°C. Supernatants (lysates) were filtered and assayed for catalase and SOD activity [24].…”