Oxidative stress responses in Escherichia coli and Salmonella typhimurium.

Farr, Spencer B.; Kogoma, T

doi:10.1128/mmbr.55.4.561-585.1991

Cited by 675 publications

(401 citation statements)

References 162 publications

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“…The yeast Saccharomyces cerevisiae exhibits two distinct protective responses to hydrogen peroxide and to O-generating agents (Jamieson, 1992;Flattery-O'Brien et al, 1993). Such distinct, but overlapping, responses were previously known in bacteria (Demple and Halbrook, 1983;Christman et al, 1985;Greenberg and Demple, 1989), where more information has become available about the actual sensors of oxidative stress (Demple, 1991;Farr and Kogoma, 1991).…”

Section: Introductionmentioning

confidence: 72%

An iron-sulfur center essential for transcriptional activation by the redox-sensing SoxR protein.

1994

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The soxRS oxidative stress regulon of Escherichia coli is triggered by superoxide (O2.‐) generating agents or by nitric oxide through two consecutive steps of gene activation. SoxR protein has been proposed as the redox sensing gene activator that triggers this cascade of gene expression. We have now characterized two forms of SoxR: Fe‐SoxR contained non‐heme iron (up to 1.6 atoms per monomer); apo‐SoxR was devoid of Fe or other metals. The spectroscopic properties of Fe‐SoxR indicated that it contains a redox active iron‐sulfur (FeS) cluster that is oxidized upon extraction from E. coli. Fe‐SoxR and apo‐SoxR bound the in vivo target, the soxS promoter, with equal affinities and protected the same region from DNase I in vitro. However, only Fe‐SoxR stimulated transcription initiation at soxS in vitro > 100‐fold, similar to the activation of soxS expression in vivo. This stimulation occurred at a step after the binding of RNAP and indicates a conformational effect of oxidized Fe‐SoxR on the soxS promoter. The variable redox state of the SoxR FeS cluster may thus be employed in vivo to modulate the transcriptional activity of this protein in response to specific types of oxidative stress.

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Section: Introductionmentioning

confidence: 72%

An iron-sulfur center essential for transcriptional activation by the redox-sensing SoxR protein.

1994

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“…In plants and animal phagocytic cells, the generation and release of AOS are thought to be important components of the host's immunity against bacterial infections. Pathogens have developed effective systems to counteract the resulting oxidative stress (for review, see [132]). For example, mutant bacteria defective in resistance to oxidative stress have been shown to be avirulent [133].…”

Section: Function In Host-pathogen Interactionsmentioning

confidence: 99%

Seleno‐independent glutathione peroxidases

2007

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Glutathione peroxidases (GPXs, EC 1.11.1.9) were first discovered in mammals as key enzymes involved in scavenging of activated oxygen species (AOS). Their efficient antioxidant activity depends on the presence of the rare amino‐acid residue selenocysteine (SeCys) at the catalytic site. Nonselenium GPX‐like proteins (NS‐GPXs) with a Cys residue instead of SeCys have also been found in most organisms. As SeCys is important for GPX activity, the function of the NS‐GPX can be questioned. Here, we highlight the evolutionary link between NS‐GPX and seleno‐GPX, particularly the evolution of the SeCys incorporation system. We then discuss what is known about the enzymatic activity and physiological functions of NS‐GPX. Biochemical studies have shown that NS‐GPXs are not true GPXs; notably they reduce AOS using reducing substrates other than glutathione, such as thioredoxin. We provide evidence that, in addition to their inefficient scavenging action, NS‐GPXs act as AOS sensors in various signal‐transduction pathways.

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“…and other Gram-negative bacteria is well known and the regulation and environmental role of these enzymes have in many cases been studied (e.g. [6,9,10]). In the present study, it was demonstrated that all the AOB studied possessed both catalase and SOD activity, but in very di¡erent proportions between strains (Table 1).…”

Section: Occurrence Of Oxidative Stress Enzymes In Aobmentioning

confidence: 99%

Catalase and superoxide dismutase activity in ammonia-oxidising bacteria

Wood¹

2001

FEMS Microbiology Ecology

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A range of ammonia-oxidising bacteria (AOB) was tested for the presence of the oxidative stress enzymes catalase and superoxide dismutase (SOD). All AOB possessed both activities, but overall activity and regulation were in several ways different among the strains. Nitrosomonas europaea contained very high specific activities of catalase compared to the other nitrifiers. Only one catalase isozyme, expressed at a constant specific activity per cell during growth in batch culture, was detectable in N. europaea by native PAGE analysis. In contrast, Nitrosospira multiformis possessed four catalase isozymes whose expression was strongly regulated by growth phase in batch culture. SOD expression patterns in the strains generally followed those of catalase, although changes of the SOD isozyme profiles were not apparent in batch culture. Growth of N. europaea on the surface of membrane filters (microcolony and biofilm formation) resulted in altered proportions of catalase and SOD specific activities, indicating regulation by cell density. This report represents the first description of different isozyme composition and of growth phase-dependent regulation of catalase and SOD enzyme production in AOB. ß

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Oxidative stress responses in Escherichia coli and Salmonella typhimurium.

Cited by 675 publications

References 162 publications

An iron-sulfur center essential for transcriptional activation by the redox-sensing SoxR protein.

An iron-sulfur center essential for transcriptional activation by the redox-sensing SoxR protein.

Seleno‐independent glutathione peroxidases

Catalase and superoxide dismutase activity in ammonia-oxidising bacteria

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