Superoxide dismutase activity in thermally stressed Staphylococcus aureus

Bucker, E R; Martin, Scott E.

doi:10.1128/aem.41.2.449-454.1981

Cited by 19 publications

(7 citation statements)

References 22 publications

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“…In order to test for the possible involvement of peroxide and superoxide in the release of Mn during peak A2, we investigated the effects of catalase and superoxide dismutase on the DSC peaks. Both of these enzymes are sufficiently thermally stable to remain active at the temperatures of peak A2 [Tm = 66 °C for catalase (Sochava et al, 1985), and superoxide dismutase loses only 5% of its activity in a 20-min incubation at 52 °C (Bucker & Martin, 1981)]. Including either of these enzymes in the PSII sample caused the A2 peak to shift to higher temperature and broaden, with little effect on the remainder of the DSC trace, as shown in Figure 8.…”

Section: Resultsmentioning

confidence: 99%

Molecular basis of the heat denaturation of photosystem II

Thompson¹,

Blaylock²,

Sturtevant³

et al. 1989

Biochemistry

112

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The thermal denaturation of the photosystem II (PSII) membrane protein complex is investigated by assigning the endothermic transitions observed by differential scanning calorimetry (DSC) to the denaturation of particular proteins of the PSII complex. In a prior DSC study of PSII membranes [Thompson, L. K., Sturtevant, J. M., & Brudvig, G. W. (1986) Biochemistry 25, 6161], five DSC peaks were observed in the 30-70 degrees C temperature range (A1, A2, B, C, and D). The A2 peak was assigned to denaturation of a component essential for water oxidation and the B peak to denaturation of a component critical to the remainder of the electron-transport chain. We have now extended these studies with thermal gel analysis and electron paramagnetic resonance (EPR) measurements. Thermal gel analysis, a technique which relies on a change in the solubility properties of a membrane protein upon denaturation, has been used to determine the temperatures of denaturation of all of the major membrane proteins of the PSII complex. EPR experiments have been used to monitor chlorophyll photooxidation and the stability of TyrD+. Peaks B, C, and D in the DSC denaturation profile are each assigned to the denaturation of several proteins, which provides information on the organization of the PSII complex into structural and functional units. Peak B corresponds to the denaturation of peripheral core proteins and closely associated antenna proteins, peak C to the PSII core, and peak D to the loosely associated antenna proteins. No membrane protein is observed to denature during the A2 peak. The A2 peak is altered by the presence of catalase, superoxide dismutase, low chloride, and high pH. These results suggest that the abnormally sharp A2 peak occurs when the highly oxidizing, sequestered Mn complex (the active site in water oxidation) becomes accessible to the aqueous phase, at elevated temperatures. We propose a mechanism for the reaction of the Mn complex with hydroxide ions, which involves peroxide or superoxide and results in the reduction and release of Mn. The proposed model provides insight into the well-known instability of the Mn complex and the role of chloride in stabilizing the complex. This may enable the future development of purification procedures and may explain the sensitivity of the water-oxidizing apparatus of PSII to heat denaturation.

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Section: Resultsmentioning

confidence: 99%

Molecular basis of the heat denaturation of photosystem II

Thompson¹,

Blaylock²,

Sturtevant³

et al. 1989

Biochemistry

112

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“…These compounds prevent the accumulation of H202 caused by the partial inactivation of cellular catalase resulting from the synergistic effects of heat and NaCl. Since the addition of catalase to selective media increased the enumeration of thermally stressed cells, it appeared likely that the addition of SOD might also increase the enumeration of thermally stressed cells, since 5 to 10% of this enzyme was inactivated under similar conditions (7). The addition of SOD did not increase the enumeration of the stressed cells on either TSAS or TSASC (data not shown).…”

Section: Resultsmentioning

confidence: 93%

Effect of free-radical scavengers on enumeration of thermally stressed cells of Staphylococcus aureus MF-31

Bucker¹,

Martin²

1982

Appl Environ Microbiol

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Exposure of crude cell lysates of Staphylococcus aureus MF-31 to 5 or 10 mM hydrogen peroxide resulted in a linear decrease in superoxide dismutase activity. Approximately 13% of the superoxide dismutase activity was lost after 16 min. Thermally stressed and nonstressed cells were exposed to a photochemically generated exogenous flux of superoxide radicals (02'). The death of thermally stressed cells was linear with time. Addition of superoxide dismutase or catalase to the O2-generating system resulted in protection of thermally stressed and nonstressed cells, with the protective effect being greater for thermally stressed cells. Incorporation of 02-, hydroxyl radical, or singlet oxygen scavengers or antioxidants to tryptic soy agar containing 7.5% NaCl did not increase the enumeration of thermally stressed cells.

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“…However, different organisms respond to elevated temperatures differently. Bucker and Martin (1981) has reported a linear decrease in SOD activity in Staphylococcus aureus at 52 ~ and under oxidative stress. Meanwhile, high temperature induced SOD activity in mammalian cells (Loven et aL 1985, Sheil et aL 1986 and in E. coli (PrivaUe and Fridovich 1987).…”

Section: Resultsmentioning

confidence: 96%

Superoxide dismutase level in response to paraquat and high temperature in the cyanobacteriumGloeocapsa sp

Hammouda¹

1994

Biol. plant.

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Paraquat (methylviologen) at concentrations above 0.05 mM inhibited the growth of photoautotrophic cyanobacterium Gloeocapsa sp. in axenic cultures. The growth rate was not affected by concentrations of 0.01 mM or less. This concentration resulted after a lag period in a moderate increase in superoxide dismutase level. After removal of paraquat, the cyanobacterium continued to generate higher levels of superoxide dismutase. There was a lag period of one hour before resumption of normal enzyme activity. Addition of puromycin at concentration of 0.5 mg cm -3 had no effect on cell survival, but greatly enhanced the sensitivity of the culture to the toxicity of paraquat. The data showed an increase of SOD activity by temperatures above the normal growth temperature level. However, this increase was suppressed by chloramphenicol which revealed that the induction of superoxide dismutase by high temperatures was associated with de novo protein synthesis.

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Superoxide dismutase activity in thermally stressed Staphylococcus aureus

Cited by 19 publications

References 22 publications

Molecular basis of the heat denaturation of photosystem II

Molecular basis of the heat denaturation of photosystem II

Effect of free-radical scavengers on enumeration of thermally stressed cells of Staphylococcus aureus MF-31

Superoxide dismutase level in response to paraquat and high temperature in the cyanobacteriumGloeocapsa sp

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