Superoxide dismutase activity in root-colonizing pseudomonads

1993 ◽  
Vol 39 (4) ◽  
pp. 420-429 ◽  
Author(s):  
J. Katsuwon ◽  
R. Zdor ◽  
A. J. Anderson
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Superoxide Anion ◽  
Plant Root ◽  
Polyacrylamide Gel Electrophoresis ◽  
Root Surface ◽  
Superoxide Anion Production ◽  
E Coli ◽  
Phosphate Availability ◽  
External Sources

Several saprophytic fluorescent pseudomonads that are aggressive root colonizers express similar specific activities of superoxide dismutase during growth in liquid culture. The pseudomonads have the potential to produce hydrogen peroxide sensitive and hydrogen peroxide insensitive isoforms of superoxide dismutase with distinct mobilities in nondenaturing polyacrylamide gel electrophoresis. Synthesis of the hydrogen peroxide insensitive form is enhanced by limited iron availability, by exposure to Mn2+, and to a lesser extent by external sources of superoxide anion. Unlike Pseudomonas aeruginosa, a root-colonizing strain of Pseudomonas putida did not show regulation of isoform pattern by phosphate availability. A plasmid potentially encoding the pseudomonad hydrogen peroxide sensitive form complemented the superoxide dismutase deficiency in a mutant of Escherichia coli lacking expression of both Fe and Mn genes. Contact between the plant root and pseudomonad or E. coli cells that lack or express superoxide dismutase did not influence superoxide anion production from root surface enzymes. The pseudomonad and the superoxide dismutase deficient and producing E. coli strains survived exposure to the root equally well. Only the hydrogen peroxide sensitive isoform of superoxide dismutase was detected in P. putida cells associated with bean root surfaces.Key words: pseudomonads, activated oxygen, root surface colonization.

scholarly journals Hypoxic human umbilical vein endothelial cells induce activation of adherent polymorphonuclear leukocytes

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3705-3716 ◽  
Author(s):  
T Arnould ◽  
C Michiels ◽  
J Remacle
Keyword(s):  
Endothelial Cells ◽  
Superoxide Dismutase ◽  
Superoxide Anion ◽  
Calcium Concentration ◽  
Molecular Mechanisms ◽  
Umbilical Vein ◽  
Superoxide Anion Production ◽  
Elastase Inhibitor ◽  
Human Umbilical Vein ◽  
Umbilical Vein Endothelial Cells

Abstract Several pieces of evidence are reported for the accumulation of activated neutrophils in ischemic and reperfused tissues leading to the transformation of the ischemic tissue into an inflammatory territory and to an enhancement of tissue damages during reoxygenation. However, the molecular mechanisms responsible for these observations and the precise role played by endothelial cells in this process are still poorly understood. In this study, an in vitro model that mimics this situation was used to investigate the effects of hypoxia-incubated human umbilical vein endothelial cells (HUVEC) on polymorphonuclear leukocyte (PMN) functions. A strong PMN activation characterized by an increase in intracellular calcium concentration as well as by superoxide anion release and leukotriene B4 production was observed when these cells were coincubated with hypoxic HUVEC. On the other hand, conditioned medium from hypoxia-incubated HUVEC failed to activate PMN, as determined by the lack of PMN calcium concentration increase, the failure of superoxide anion production enhancement, as well as the absence of effects on the integrin CD18, CD11a, and CD11b expression. These results indicate that the presence of hypoxia- incubated HUVEC is necessary to obtain an activation of the PMN, probably via the adherence process. Once activated by coincubation with hypoxic HUVEC, PMN became cytotoxic, as evidenced by 51Cr released from prelabeled HUVEC. This cytotoxic effect of activated PMN for hypoxic endothelial cells could be prevented by a combination of superoxide dismutase and catalase (94% inhibition), whereas superoxide dismutase alone was inefficient. Antiprotease (alpha 2-macroglobulin) and a specific elastase inhibitor (MAAPV-CMK) were also inefficient. These results correlate very well with the fact that no increase in elastase release could be observed in supernatants from PMN coincubated with hypoxic HUVEC. Furthermore, when adherence process was blocked by oleic acid or by anti-ICAM-1 monoclonal antibodies, protection was, respectively, 90% and 72%. We thus evidenced that free radicals but not elastase released from activated PMN coincubated with hypoxic HUVEC are involved in HUVEC injury. We conclude from these results that PMN activation is initiated by PMN adherence to hypoxic HUVEC. These observations indicate that hypoxic HUVEC may be partly responsible for neutrophil activation observed in ischemic tissues, which is part of the amplification process of tissue damage.

Haematoporphyrin enhances the peroxidase activity of haemoglobin

2000 ◽  
Vol 04 (02) ◽  
pp. 168-174 ◽  
Author(s):  
SUSMITA SIL ◽  
MANOJ KAR ◽  
ABHAY SANKAR CHAKRABORTI
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Conformational Change ◽  
Anticancer Drugs ◽  
Peroxidase Activity ◽  
Superoxide Anion ◽  
Spectrophotometric Study ◽  
Stoichiometric Ratio ◽  
Mediated Oxidation

The effect of haematoporphyrin, a component of some of the widely used anticancer drugs, on the peroxidase activity of haemoglobin has been studied. Haematoporphyrin increases the haemoglobin-catalysed hydrogen peroxide-mediated oxidation of o-dianisidine or NADH. Spectrophotometric study reveals that an interaction occurs between haemoglobin and haematoporphyrin which leads to a conformational change of the protein. The extent of enhanced peroxidase activity as well as conformational change of the protein vary in a positive manner with the stoichiometric ratio of haematoporphyrin/haemoglobin. An increase in the peroxidase activity of haemoglobin was also observed in the presence of superoxide dismutase, which catalysed the removal of superoxide anion generated during autoxidation of haemoglobin. Possible mechanisms underlying the relation between the conformational change of haemoglobin due to its interaction with haematoporphyrin and the enhanced peroxidase activity are discussed.

Peroxidase associated with the root surface of Phaseolus vulgaris

1986 ◽  
Vol 64 (3) ◽  
pp. 573-578 ◽  
Author(s):  
F. G. Albert ◽  
L. W. Bennett ◽  
A. J. Anderson
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Anion ◽  
Indoleacetic Acid ◽  
Root Surface ◽  
Acid Oxidase ◽  
Peroxide Formation ◽  
Optimal Activity ◽  
Indoleacetic Acid Oxidase ◽  
Hydrogen Peroxide Formation ◽  
Intact Roots

The surface of bean roots demonstrates an intense peroxidase activity which was detected by hydrogen peroxide dependent formation of chromogen from chloronaphthol or dianisidine. Other peroxidase functions, oxidation of indoleacetic acid and NADPH, were catalysed by intact roots and were stimulated by Mn2+ and p-coumarate. Oxidation of NADPH involved superoxide anion [Formula: see text] and hydrogen peroxide formation. Molecular sizing chromatography of root washes demonstrated NADPH oxidase and peroxidase to be associated with higher weight components than indoleacetic acid oxidase. Root surface and root wash peroxidase displayed optimal activity between pH 7 and 8, whereas both sources of indoleacetic acid oxidase were more active at acidic pH. Native poly aery lamide gel electrophoresis of sterile root washes displayed two fast-moving anodic bands, whereas homogenates of the plant roots had several slower moving bands in addition.

Further investigation of the mechanism of Vitreoscilla hemoglobin (VHb) protection from oxidative stress in Escherichia coli

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Meltem Akbas ◽  
Tugrul Doruk ◽  
Serhat Ozdemir ◽  
Benjamin Stark
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Stationary Phase ◽  
Exponential Phase ◽  
Vitreoscilla Hemoglobin ◽  
Sod Activity ◽  
E Coli ◽  
Hydrogen Peroxide Treatment

AbstractIn Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures of SOD+ or SOD− E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels.

scholarly journals Endogenous superoxide is a key effector of the oxygen sensitivity of a model obligate anaerobe

2018 ◽  
Vol 115 (14) ◽  
pp. E3266-E3275 ◽  
Author(s):  
Zheng Lu ◽  
Ramakrishnan Sethu ◽  
James A. Imlay
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Major Element ◽  
Oxygen Sensitivity ◽  
Obligate Anaerobe ◽  
Human Gastrointestinal Tract ◽  
E Coli ◽  
Mononuclear Iron ◽  
Enzyme Families ◽  
Species Production

It has been unclear whether superoxide and/or hydrogen peroxide play important roles in the phenomenon of obligate anaerobiosis. This question was explored usingBacteroides thetaiotaomicron, a major fermentative bacterium in the human gastrointestinal tract. Aeration inactivated two enzyme families—[4Fe-4S] dehydratases and nonredox mononuclear iron enzymes—whose homologs, in contrast, remain active in aerobicEscherichia coli. Inactivation-rate measurements of one such enzyme,B. thetaiotaomicronfumarase, showed that it is no more intrinsically sensitive to oxidants than is anE. colifumarase. Indeed, when theE. colienzymes were expressed inB. thetaiotaomicron, they no longer could tolerate aeration; conversely, theB. thetaiotaomicronenzymes maintained full activity when expressed in aerobicE. coli. Thus, the aerobic inactivation of theB. thetaiotaomicronenzymes is a feature of their intracellular environment rather than of the enzymes themselves.B. thetaiotaomicronpossesses superoxide dismutase and peroxidases, and it can repair damaged enzymes. However, measurements confirmed that the rate of reactive oxygen species production inside aeratedB. thetaiotaomicronis far higher than inE. coli. Analysis of the damaged enzymes recovered from aeratedB. thetaiotaomicronsuggested that they had been inactivated by superoxide rather than by hydrogen peroxide. Accordingly, overproduction of superoxide dismutase substantially protected the enzymes from aeration. We conclude that when this anaerobe encounters oxygen, its internal superoxide levels rise high enough to inactivate key catabolic and biosynthetic enzymes. Superoxide thus comprises a major element of the oxygen sensitivity of this anaerobe. The extent to which molecular oxygen exerts additional direct effects remains to be determined.

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