Search results for "Oxide"
showing 10 items of 6424 documents
NO contributes to cadmium toxicity in Arabidopsis thaliana by mediating an iron deprivation response
2009
Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd(2+)), a nonessential and toxic metal. We demonstrate that Cd(2+) induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors, does not involve nitrate reductase and AtNOA1 but requires IRT1, encoding a major plasma membrane transporter for iron but also Cd(2+). By analyzing the incidence of NO scavenging or inhibition of …
NADPH Oxidase-Mediated Reactive Oxygen Species Production: Subcellular Localization and Reassessment of Its Role in Plant Defense
2009
International audience; Chemiluminescence detection of reactive oxygen species (ROS) triggered in tobacco BY-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane NADPH oxidase, NtrbohD. Here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and NtrbohD mediated. Furthermore, the presence of NtrbohD in detergent-resistant membrane fractions could be associated with the presence of NtrbohD-mediated hydrogen peroxide patches along the plasma membran…
Glutathione deficiency of the Arabidopsis mutant pad2-1 affects oxidative stress-related events, defense gene expression and hypersensitive response
2011
L'article original est publié par The American Society of Plant Biologists; International audience; The Arabidopsis (Arabidopsis thaliana) phytoalexin-deficient mutant pad2-1 displays enhanced susceptibility to a broad range of pathogens and herbivorous insects that correlates with deficiencies in the production of camalexin, indole glucosinolates, and salicylic acid (SA). The pad2-1 mutation is localized in the GLUTAMATE-CYSTEINE LIGASE (GCL) gene encoding the first enzyme of glutathione biosynthesis. While pad2-1 glutathione deficiency is not caused by a decrease in GCL transcripts, analysis of GCL protein level revealed that pad2-1 plants contained only 48% of the wild-type protein amoun…
Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses
2008
International audience; It was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular N…
S-nitrosylation: An emerging post-translational protein modification in plants
2011
International audience; Increasing evidences support the assumption that nitric oxide (NO) acts as a physiological mediator in plants. Understanding its pleiotropic effects requires a deep analysis of the molecular mechanisms underlying its mode of action. In the recent years, efforts have been made in the identification of plant proteins modified by NO at the post-translational level, notably by S-nitrosylation. This reversible process involves the formation of a covalent bond between NO and reactive cysteine residues. This research has now born fruits and numerous proteins regulated by S-nitrosylation have been identified and characterized. This review describes the basic principle of S-n…
Current view of nitric oxide-responsive genes in plants
2009
International audience; Significant efforts have been directed towards the identification of genes differentially regulated through nitric oxide (NO)-dependent processes. These efforts comprise the use of medium- and large-scale transcriptomic analyses including microarray and cDNA-amplification fragment length polymorphism (AFLP) approaches. Numerous putative NO-responsive genes have been identified in plant tissues and cell suspensions with transcript levels altered by artificially released NO, or endogenously produced. Comparative analysis of the data from such transcriptomic analyses in Arabidopsis reveals that a significant part of these genes encode proteins related to plant adaptive …
Nitric oxide: comparative synthesis and signaling in animal and plant cells.
2001
Since its identification as an endothelium-derived relaxing factor in the 1980s, nitric oxide has become the source of intensive and exciting research in animals. Nitric oxide is now considered to be a widespread signaling molecule involved in the regulation of an impressive spectrum of mammalian cellular functions. Its diverse effects have been attributed to an ability to chemically react with dioxygen and its redox forms and with specific iron- and thiol-containing proteins. Moreover, the effects of nitric oxide are dependent on the dynamic regulation of its biosynthetic enzyme nitric oxide synthase. Recently, the role of nitric oxide in plants has received much attention. Plants not only…
Nitric oxide signalling in plants: interplays with Ca2+ and protein kinase
2008
International audience; Much attention has been paid to nitric oxide (NO)research since its discovery as a physiological mediator of plant defence responses. In recent years, newer roles have been attributed to NO, ranging from root development to stomatal closure. The molecular mechanisms underlying NO action in plants are just begun to emerge. The currently available data illustrate that NO can directly influence the activity of target proteins through nitrosylation and has the capacity to act as a Ca2+-mobilizing intracellular messenger. The interplay between NO and Ca2+ has important functional implications, expanding and enriching the possibilities for modulating transduction processes…
Carbon metabolic rates and GHG emissions in different wetland types of the Ebro Delta
2020
Deltaic wetlands are highly productive ecosystems, which characteristically can act as C-sinks. However, they are among the most threatened ecosystems, being very vulnerable to global change, and require special attention towards its conservation. Knowing their climate change mitigating potential, conservation measures should also be oriented with a climatic approach, to strengthen their regulatory services. In this work we studied the carbon biogeochemistry and the specific relevance of certain microbial guilds on carbon metabolisms of the three main types of deltaic wetlands located in the Ebro Delta, north-eastern Spain, as well as how they deal with human pressures and climate change ef…
Volcanic CO2 seep geochemistry and use in understanding ocean acidification
2020
AbstractOcean acidification is one of the most dramatic effects of the massive atmospheric release of anthropogenic carbon dioxide (CO2) that has occurred since the Industrial Revolution, although its effects on marine ecosystems are not well understood. Submarine volcanic hydrothermal fields have geochemical conditions that provide opportunities to characterise the effects of elevated levels of seawater CO2 on marine life in the field. Here, we review the geochemical aspects of shallow marine CO2-rich seeps worldwide, focusing on both gas composition and water chemistry. We then describe the geochemical effects of volcanic CO2 seepage on the overlying seawater column. We also present new g…