Superoxide Free Radicals Are Produced in Glyoxysomes

Sandalio, Luisa M.; Fernández, Vı́ctor M.; Rupérez, Francisco López; Rı́o, Luis A. del

doi:10.1104/pp.87.1.1

Cited by 101 publications

(55 citation statements)

References 16 publications

(15 reference statements)

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“…In addition, 02*-formation in glyoxysomes has been reported (21). GST showed a significant decrease, which suggests that this enzyme is not involved in the metabolism of 50H-NQ.…”

mentioning

confidence: 93%

The Effect of 5OH-1,4-Naphthoquinone on Norway Spruce Seeds during Germination

Segura‐Aguilar¹,

Hakman²,

Rydström³

1992

Plant Physiol.

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The effect of 5-OH-1,4-naphthoquinone (50H-NQ), a known inhibitor of germination and growth and an inducer of oxidative stress, on seeds from Norway spruce (Picea abies) during germination was studied. 50H-NQ was activated by homogenate from seeds to reactive species that reduce oxygen to superoxide radicals in vitro. Increasing concentrations of 50H-NQ increased lipid peroxidation during this activation. Small effects of 50H-NQ on germination of seeds were observed at concentrations up to 200 Mm. However, higher concentrations, e.g. 500 and 1000 AM, exerted more pronounced effects on seeds. These results suggest that the effect of 50H-NQ was a delay rather than an inhibition of germination. However, the effect of 50H-NQ on postgerminative growth was more potent than that on germination, and higher concentrations inhibited growth >97%. These results suggest that the seeds have a very effective defense system against quinone and reactive oxygen species, since the small effects of 50H-NQ on germination and postgermination at concentrations up to 200 AM can be explained by the formation of a metabolite of 50H-NQ that is not as reactive with oxygen as the original quinone. The 50H-NQ metabolite collected during germination experiments showed differences in its absorption spectrum in comparison with 50H-NQ, which suggest changes in structure. This metabolite was reduced by quinone reductase, but reduction of oxygen to superoxide radicals was not detected during its activation with homogenate from seeds. This metabolite may arise via a conjugation reaction, since the addition of 500 Mm uridine 5'-diphosphoglucuronic acid or 3'-phosphoadenosine-5'-phosphosulfate to the incubation mixture during activation of this metabolite by homogenate from seeds in vitro inhibited reduction of oxygen to superoxide radicals by 50 and 64%, respectively. The constitutive levels of superoxide dismutase and catalase were sufficient to prevent oxygen toxicity during activation of 50H-NQ, since these enzymes were not induced when the seeds were treated with 200 AM 50H-NQ.

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“…In addition, 02*-formation in glyoxysomes has been reported (21). GST showed a significant decrease, which suggests that this enzyme is not involved in the metabolism of 50H-NQ.…”

mentioning

confidence: 93%

The Effect of 5OH-1,4-Naphthoquinone on Norway Spruce Seeds during Germination

Segura‐Aguilar¹,

Hakman²,

Rydström³

1992

Plant Physiol.

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“…chloroplasts (1), microsomes (17), and nuclei (18). Recently the production of 02-in glyoxysomes has been demonstrated both in the supernatants, induced by xanthine and hypoxanthine, and in membranes, stimulated by NADH (23). Superoxide production by purines was due to xanthine oxidase (EC 1.1.3.22), which was found predominantly in the matrix of glyoxysomes (23).…”

mentioning

confidence: 99%

“…Recently the production of 02-in glyoxysomes has been demonstrated both in the supernatants, induced by xanthine and hypoxanthine, and in membranes, stimulated by NADH (23). Superoxide production by purines was due to xanthine oxidase (EC 1.1.3.22), which was found predominantly in the matrix of glyoxysomes (23). However, no information is available on the production of oxygen free radicals in leaf peroxisomes and this is important in order to know whether the reported generation of superoxide radicals by glyoxysomes can be extended to other classes of peroxisomes with different functional specialization in cellular metabolism.…”

mentioning

confidence: 99%

NADH Induces the Generation of Superoxide Radicals in Leaf Peroxisomes

Rı́o

Fernández²,

Rupérez³

et al. 1989

Plant Physiol.

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In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (02-) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of 02-radicals. In the soluble fractions of peroxisomes, no generation of 02-radicals was observed by incubation with either NADH or xanthine, although xanthine oxidase was found located predominantly in the matrix of peroxisomes. The failure of xanthine to induce superoxide generation was probably due to the inability to fully suppress the endogenous Mn-superoxide dismutase activity by inhibitors which were inactive against xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes (LM Sandallo, VM Femandez, FL Rup6rez, LA del Rio [1988] Plant Physiol 87: 1-4) suggests that 02-generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related roles for peroxisomes in cellular metabolism.Peroxisomes are subcellular respiratory organelles containing as basic enzymic constituents catalase and, at least, one H202-producing flavin oxidase, and have different metabolic pathways depending upon their origin (15,26). Recently, we have demonstrated the presence of SOD2 activity (EC 1.15.1.1) in peroxisomes from pea leaves (6,22) and in glyoxysomes from watermelon cotyledons (21), a class of specialized peroxisomes occurring in oilseeds. In leaf peroxisomes, a Mn-containing SOD is present (22) and the study of the intraorganellar distribution ofthis metalloenzyme showed that Mn-SOD was located in the peroxisomal matrix as a soluble enzyme (24).

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“…Plants produce ROS in the early stages of pathogen invasion as part of their mechanism to defend themselves; hence, production of antioxidants is important for virulence of plant pathogens (14)(15)(16). One of the mechanisms by which host plants produce ROS is by activating xanthine oxidase.…”

mentioning

confidence: 99%

“…and other bacteria, secretion of antibiotics is thought to be one of their important strategies during this competition (19)(20)(21). In this complex ecological environment, many organisms (such as plants) employ the strategy of producing ROS in defense against invading pathogens (14)(15)(16). For organisms that inhabit the rhizosphere, mechanisms must therefore be in place to respond to incidental exposure to ROS and other secreted compounds.…”

mentioning

confidence: 99%

Streptomyces coelicolor Encodes a Urate-Responsive Transcriptional Regulator with Homology to PecS from Plant Pathogens

2013

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Many transcriptional regulators control gene activity by responding to specific ligands. Members of the multiple-antibiotic resistance regulator (MarR) family of transcriptional regulators feature prominently in this regard, and they frequently function as repressors in the absence of their cognate ligands. Plant pathogens such as Dickeya dadantii encode a MarR homolog named PecS that controls expression of a gene encoding the efflux pump PecM in addition to other virulence genes. We report here that the soil bacterium Streptomyces coelicolor also encodes a PecS homolog (SCO2647) that regulates a pecM gene (SCO2646). S. coelicolor PecS, which exists as a homodimer, binds the intergenic region between pecS and pecM genes with high affinity. Several potential PecS binding sites were found in this intergenic region. The binding of PecS to its target DNA can be efficiently attenuated by the ligand urate, which also quenches the intrinsic fluorescence of PecS, indicating a direct interaction between urate and PecS. In vivo measurement of gene expression showed that activity of pecS and pecM genes is significantly elevated after exposure of S. coelicolor cultures to urate. These results indicate that S. coelicolor PecS responds to the ligand urate by attenuated DNA binding in vitro and upregulation of gene activity in vivo. Since production of urate is associated with generation of reactive oxygen species by xanthine dehydrogenase, we propose that PecS functions under conditions of oxidative stress.

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Superoxide Free Radicals Are Produced in Glyoxysomes

Cited by 101 publications

References 16 publications

The Effect of 5OH-1,4-Naphthoquinone on Norway Spruce Seeds during Germination

The Effect of 5OH-1,4-Naphthoquinone on Norway Spruce Seeds during Germination

NADH Induces the Generation of Superoxide Radicals in Leaf Peroxisomes

Streptomyces coelicolor Encodes a Urate-Responsive Transcriptional Regulator with Homology to PecS from Plant Pathogens

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