Oxygen radicals produced by plant plasma membranes: an EPR spin-trap study

Mojović, Miloš; Vuletić, Mirjana; Bačić, Goran; Vučinić, Željko

doi:10.1093/jxb/erh266

Cited by 36 publications

(47 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is especially true in those cases in which O 2 Á2 production cannot be inhibited by even high concentrations of DPI and in which a significant part of XTT or Cyt c reduction is resistant to inhibition by SOD. Examples of striking DPI insensitivity of O 2 Á2 production or transmembrane electron transport by plasma membrane vesicles have been reported (Menckhoff and Lü thje, 2004;Mojović et al, 2004). As shown here, the NQR purified from plasma membranes has a potential to elicit O 2 Á2 production, unaffected by DPI, if supplied with a quinone substrate such as MD.…”

Section: Potential Function Of Nqr In the Plasma Membrane Of Intact Csupporting

confidence: 52%

Naphthoquinone-Dependent Generation of Superoxide Radicals by Quinone Reductase Isolated from the Plasma Membrane of Soybean

et al. 2008

View full text Add to dashboard Cite

Using a tetrazolium-based assay, a NAD(P)H oxidoreductase was purified from plasma membranes prepared from soybean (Glycine max) hypocotyls. The enzyme, a tetramer of 85 kD, produces O 2 Á2 by a reaction that depended on menadione or several other 1,4-naphthoquinones, in apparent agreement with a classification as a one-electron-transferring flavoenzyme producing semiquinone radicals. However, the enzyme displayed catalytic and molecular properties of obligatory two-electrontransferring quinone reductases of the DT-diaphorase type, including insensitivity to inhibition by diphenyleneiodonium. This apparent discrepancy was clarified by investigating the pH-dependent reactivity of menadionehydroquinone toward O 2 and identifying the protein by mass spectrometry and immunological techniques. The enzyme turned out to be a classical NAD(P)H:quinone-acceptor oxidoreductase (EC 1.6.5.2, formerly 1.6.99.2) that reduces menadione to menadionehydroquinone and subsequently undergoes autoxidation at pH $ 6.5. Autoxidation involves the production of the semiquinone as an intermediate, creating the conditions for one-electron reduction of O 2 . The possible function of this enzyme in the generation of O 2 Á2 and H 2 O 2 at the plasma membrane of plants in vivo is discussed.

show abstract

Section: Potential Function Of Nqr In the Plasma Membrane Of Intact Csupporting

confidence: 52%

Naphthoquinone-Dependent Generation of Superoxide Radicals by Quinone Reductase Isolated from the Plasma Membrane of Soybean

et al. 2008

View full text Add to dashboard Cite

show abstract

“…It is likely that this reaction occurs in vivo because all of the reagents required are present in the plant cell wall (Fry, 1998). However, there is also evidence for enzymatic production of c OH in plasma membrane extracts that is stimulated by NADH and insensitive to oxygen, indicating a mechanism independent of superoxide (Mojovic et al, 2004). H 2 O 2 production is correlated with the stiffening of cell walls as growth ceases in a number of cell types.…”

Section: Cell Wall Loosening and Tightening Are Mediated By Rosmentioning

confidence: 99%

Control of Plant Development by Reactive Oxygen Species

2006

View full text Add to dashboard Cite

Reactive oxygen species (ROS) are emerging as important regulators of plant development. There is now abundant evidence that ROS play roles in cell growth and that spatial regulation of ROS production is an important factor controlling plant form. Here we will review evidence that supports a role for ROS in development, but first we will define what we mean by development. The body of the vascular plant sporophyte (diploid life cycle stage) is derived from meristems and much of the action of development occurs where organs are formed in and around meristems (Martienssen and Dolan, 1998). Organogenesis, the development of organs, involves an early patterning stage that roughs out boundaries where the organs will form. Within these boundaries, groups of founder cells divide and growth occurs, leading to the formation of structures containing arrays of differentiated cells. There are two major contributors to growth: First, there is cell division, which increases the number of cells in an organ; second, there is expansion of those cells. The huge increase in volume in plant cells as they transit from the founder population in and around meristems to the differentiated cells of the mature organ means that cell growth is an important component of plant development (Sugimoto-Shirasu and Roberts, 2003). Recent discoveries suggest that ROS may control development through their role in regulating cell growth. NADPH OXIDASES GENERATE ROS INVOLVED IN DEVELOPMENTROS that have been shown to play a role in development are produced by NADPH oxidases (NOXs) that generate the superoxide radical (O 2 c 2

show abstract

“…3 (spectrum 3A). By comparing the EPR spectra of DEPMPO/OH and DEPMPO/OOH adducts, which were formed in chemical systems generating ·OH and O 2 -·, respectively, with spectrum 3A ( Mojović et al, 2004 ), we could conclude that the spectrum of the DEPMPO/ OH adduct was contained in spectrum 3A. Computer simulation of the spectra (dashed line in spectrum 3A) supported the presence of EPR signals of the DEPMPO/OH adduct in spectrum 3A.…”

Section: Formation Of ·Oh In Cell Wall Isolatesmentioning

confidence: 77%

“…Involvement of the superoxide anion radical in ·OH production by the cell wall has been proposed in the literature ( Chen and Schopfer 1999, Liszkay et al 2004, Karkonen and Fry 2006. Various cellular components including plasma membranes were shown to be capable of generating O 2 -· ( Vuletić et al 2003, Mojović et al 2004. Plasma membrane-bound NADH oxidase has been implicated, based on an inhibitory effect of iodonium compounds, as a crucial enzyme responsible for the generation of O 2 -· in the apoplast ( Doke 1985, Murphy and Auh 1996, van Gestelen et al 1997.…”

Section: Introductionmentioning

confidence: 99%

“…To discuss the mechanism of ·OH production, mechanisms of production of O 2 -· and H 2 O 2 were also studied, taking O 2 -dependent oxidation of hydroxycinnamic acids into consideration. ·OH and O 2 -· generated in cell wall isolates were detected using a spintrapping reagent, 5-(diethoxyphosphoryl)-5-methyl-1-pyroline N -oxide (DEPMPO), due to its capacity to differentiate between O 2 -· and ·OH ( Frejaville et al 1995, Mojović et al 2004 ). The results obtained in this study suggest that cell wall isolates could reduce O 2 to O 2 -· by auto-oxidation of hydroxycinnamic acids bound to the cell wall, which in turn can be transformed by cell wall-bound SOD to H 2 O 2 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Generation of Hydroxyl Radical in Isolated Pea Root Cell Wall, and the Role of Cell Wall-Bound Peroxidase, Mn-SOD and Phenolics in Their Production

Kukavica¹,

Mojović

Vucčinić³

et al. 2008

Plant and Cell Physiology

View full text Add to dashboard Cite

The hydroxyl radical produced in the apoplast has been demonstrated to facilitate cell wall loosening during cell elongation. Cell wall-bound peroxidases (PODs) have been implicated in hydroxyl radical formation. For this mechanism, the apoplast or cell walls should contain the electron donors for (i) H 2 O 2 formation from dioxygen; and (ii) the POD-catalyzed reduction of H 2 O 2 to the hydroxyl radical. The aim of the work was to identify the electron donors in these reactions. In this report, hydroxyl radical (·OH) generation in the cell wall isolated from pea roots was detected in the absence of any exogenous reductants, suggesting that the plant cell wall possesses the capacity to generate ·OH in situ. Distinct POD and Mn-superoxide dismutase (Mn-SOD) isoforms different from other cellular isoforms were shown by native gel electrophoresis to be preferably bound to the cell walls. Electron paramagnetic resonance (EPR) spectroscopy of cell wall isolates containing the spin-trapping reagent, 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N -oxide (DEPMPO), was used for detection of and differentiation between ·OH and the superoxide radical (O 2 -·). The data obtained using POD inhibitors confi rmed that tightly bound cell wall PODs are involved in DEPMPO/OH adduct formation. A decrease in DEPMPO/OH adduct formation in the presence of H 2 O 2 scavengers demonstrated that this hydroxyl radical was derived from H 2 O 2 . During the generation of ·OH, the concentration of quinhydrone structures (as detected by EPR spectroscopy) increased, suggesting that the H 2 O 2 required for the formation of ·OH in isolated cell walls is produced during the reduction of O 2 by hydroxycinnamic acids. Cell wall isolates in which the proteins have been denaturated (including the endogenous POD and SOD) did not produce ·OH. Addition of exogenous H 2 O 2 again induced the production of ·OH, and these were shown to originate from the Fenton reaction with tightly bound metal ions. However, the appearance of the DEPMPO/OOH adduct could also be observed, due to the production of O 2 -· when endogenous SOD has been inactivated. Also, O 2 -· was converted to ·OH in an in vitro horseradish peroxidase (HRP)/H 2 O 2 system to which exogenous SOD has been added. Taken together with the discovery of the cell wall-bound Mn-SOD isoform, these results support the role of such a cell wall-bound SOD in the formation of ·OH jointly with the cell wallbound POD. According to the above fi ndings, it seems that the hydroxycinnamic acids from the cell wall, acting as reductants, contribute to the formation of H 2 O 2 in the presence of O 2 in an autocatalytic manner, and that POD and Mn-SOD coupled together generate ·OH from such H 2 O 2 .

show abstract

Oxygen radicals produced by plant plasma membranes: an EPR spin-trap study

Cited by 36 publications

References 32 publications

Naphthoquinone-Dependent Generation of Superoxide Radicals by Quinone Reductase Isolated from the Plasma Membrane of Soybean

Naphthoquinone-Dependent Generation of Superoxide Radicals by Quinone Reductase Isolated from the Plasma Membrane of Soybean

Control of Plant Development by Reactive Oxygen Species

Generation of Hydroxyl Radical in Isolated Pea Root Cell Wall, and the Role of Cell Wall-Bound Peroxidase, Mn-SOD and Phenolics in Their Production

Contact Info

Product

Resources

About