1-3-dimethylthiourea and diphenyleneiodonium

NADPH oxidase-mediated H

Topics: Cell Membrane; Hydrogen Peroxide; Lipid Peroxidation; NADPH Oxidases; Onium Compounds; Ornithine-Oxo-Acid Transaminase; Plant Roots; Proline; Proline Oxidase; Salinity; Salt Stress; Salt Tolerance; Seedlings; Thiourea; Triticum

Protein Phosphatase 2C (PP2C) is an important phosphatase-like protein in eukaryotic organisms that can negatively regulate protein kinase cascade abscisic acid (ABA) signal system through phosphorylation and carry out vital roles in various cell processes. The previous study indicated that the accumulation of reactive oxygen species (ROS) is a part of mechanism of glucohexaose-induced resistance in cucumber cotyledons, and CsPP2C80s might play a crucial role in processes related to ROS produce and signal transduction. To identify the mechanism of CsPP2C80s involved in glucohexaose and ABA signaling regulating cell redox status, the effects of glucohexaose and ROS inhibitor pretreatment on endogenous ABA content and ABA signaling genes expression levels of cucumber seedlings were analysed. These results suggest that cucumber CsPP2C80s are involved in ROS accumulation and ABA signal transduction pathway induced by glucohexaose, CsPP2C80s play a positive regulatory role in process of ABA combined with ABA receptors (PYLs) to activate SNF1-related protein kinases 2 (SnRK2s) and regulate NADPH oxidase to produce extracellular hydrogen peroxide (H2O2), providing unequivocal molecular evidence of PP2C-mediated ABA response mechanisms functioning in cell redox status induced by glucohexaose.

Topics: Abscisic Acid; Cucumis sativus; Free Radical Scavengers; Gene Expression Regulation, Plant; NADPH Oxidases; Oligosaccharides; Onium Compounds; Oxidation-Reduction; Phosphorylation; Plant Cells; Plant Proteins; Protein Phosphatase 2C; Seedlings; Signal Transduction; Thiourea

2-(2-Phenylethyl)chromones are the main compounds responsible for the quality of agarwood, which is widely used in traditional medicines, incenses and perfumes. H

Topics: Amino Acid Sequence; Flavonoids; Hydrogen Peroxide; NADPH Oxidases; Onium Compounds; Phylogeny; Plant Proteins; Sequence Alignment; Sodium Chloride; Stress, Physiological; Thiourea; Thymelaeaceae

In hulless barley, H 2 S mediated increases in H 2 O 2 induced by putrescine, and their interaction enhanced tolerance to UV-B by maintaining redox homeostasis and promoting the accumulation of UV-absorbing compounds. This study investigated the possible relationship between putrescence (Put), hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) as well as the underlying mechanism of their interaction in reducing UV-B induced damage. UV-B radiation increased electrolyte leakage (EL) and the levels of malondialdehyde (MDA) and UV-absorbing compounds but reduced antioxidant enzyme activities and glutathione (GSH) and ascorbic acid (AsA) contents. Exogenous application of Put, H2S or H2O2 reduced some of the above-mentioned negative effects, but were enhanced by the addition of Put, H2S and H2O2 inhibitors. Moreover, the protective effect of Put against UV-B radiation-induced damage to hulless barley was diminished by DL-propargylglycine (PAG, a H2S biosynthesis inhibitor), hydroxylamine (HT, a H2S scavenger), diphenylene iodonium (DPI, a PM-NADPH oxidase inhibitor) and dimethylthiourea (DMTU, a ROS scavenger), and the effect of Put on H2O2 accumulation was abolished by HT. Taken together, as the downstream component of the Put signaling pathway, H2S mediated H2O2 accumulation, and H2O2 induced the accumulation of UV-absorbing compounds and maintained redox homeostasis under UV-B stress, thereby increasing the tolerance of hulless barley seedlings to UV-B stress.

Topics: Alkynes; Antioxidants; Ascorbic Acid; Enzyme Inhibitors; Glutathione; Glycine; Homeostasis; Hordeum; Hydrogen Peroxide; Hydrogen Sulfide; Hydroxylamine; NADPH Oxidases; Onium Compounds; Oxidation-Reduction; Oxidative Stress; Plant Proteins; Protective Agents; Putrescine; Seedlings; Signal Transduction; Thiourea; Ultraviolet Rays

Root hairs are plastic in response to nutrient supply, but relatively little is known about their development under low ammonium (NH4(+)) conditions. This study showed that reducing NH4(+) for 3 days in wild-type Arabidopsis seedlings resulted in drastic elongation of root hairs. To investigate the possible mediation of ethylene and auxin in this process, seedlings were treated with 2,3,5-triiodobenzoic acid (TIBA, auxin transport inhibitor), 1-naphthylphthalamic acid (NPA, auxin transport inhibitor), p-chlorophenoxy isobutyric acid (PCIB, auxin action inhibitor), aminoethoxyvinylglycine (AVG, chemical inhibitor of ethylene biosynthesis), or silver ions (Ag(+), ethylene perception antagonist) under low NH4(+) conditions. Our results showed that TIBA, NPA and PCIB did not inhibit root hair elongation under low NH4(+) conditions, while AVG and Ag(+) completely inhibited low NH4(+)-induced root hair elongation. This suggested that low NH4(+)-induced root hair elongation was dependent on the ethylene pathway, but not the auxin pathway. Further genetic studies revealed that root hair elongation in auxin-insensitive mutants was sensitive to low NH4(+) treatment, but elongation was less sensitive in ethylene-insensitive mutants than wild-type plants. In addition, low NH4(+)-induced root hair elongation was accompanied by reactive oxygen species (ROS) accumulation. Diphenylene iodonium (DPI, NADPH oxidase inhibitor) and dimethylthiourea (DMTU, ROS scavenger) inhibited low NH4(+)-induced root hair elongation, suggesting that ROS were involved in this process. Moreover, ethylene acted together with ROS to modulate root hair elongation under low NH4(+) conditions. These results demonstrate that a signaling pathway involving ethylene and ROS participates in regulation of root hair elongation when Arabidopsis seedlings are subjected to low NH4(+) conditions.

Topics: Ammonium Compounds; Arabidopsis; Ethylenes; Glycine; Indoleacetic Acids; Models, Biological; Onium Compounds; Plant Roots; Reactive Oxygen Species; Seedlings; Thiourea

The involvement of hydrogen peroxide (H2O2) generated by nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) in the antioxidant defense system was assessed in salt-challenged Arabidopsis thaliana seedlings. In the wild-type, short-term salt exposure led to a transient and significant increase of H2O2 concentration, followed by a marked increase in catalase (CAT, EC 1.11.16), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) activities. Pre-treatment with either a chemical trap for H2O2 (dimethylthiourea) or two widely used NADPH oxidase inhibitors (imidazol and diphenylene iodonium) significantly decreased the above-mentioned enzyme activities under salinity. Double mutant atrbohd/f plants failed to induce the antioxidant response under the culture conditions. Under long-term salinity, the wild-type was more salt-tolerant than the mutant based on the plant biomass production. The better performance of the wild-type was related to a significantly higher photosynthetic activity, a more efficient K(+) selective uptake, and to the plants' ability to deal with the salt-induced oxidative stress as compared to atrbohd/f. Altogether, these data suggest that the early H2O2 generation by NADPH oxidase under salt stress could be the beginning of a reaction cascade that triggers the antioxidant response in A. thaliana in order to overcome the subsequent reactive oxygen species (ROS) production, thereby mitigating the salt stress-derived injuries.

Topics: Antioxidants; Arabidopsis; Arabidopsis Proteins; Ascorbate Peroxidases; Catalase; Fluoresceins; Gene Expression Regulation, Plant; Glutathione Reductase; Hydrogen Peroxide; Imidazoles; Malondialdehyde; Mutation; NADPH Oxidases; Onium Compounds; Sodium Chloride; Stress, Physiological; Thiourea; Time Factors

Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.

Topics: Acid Sensing Ion Channel Blockers; Amiloride; Arabidopsis; Cell Membrane; Glycerol; Hydrogen Peroxide; Hydrogen Sulfide; NADPH Oxidases; Onium Compounds; Sodium Chloride; Sulfides; Thiourea; Vanadates

We have previously found that reactive oxygen species (ROS) are involved in Pseudomonas aeruginosa lipopolysaccharide (PA-LPS) induced MUC5AC in airway epithelial cells. Dual oxidase1 (Duox1), a member of NADPH oxidase(Nox), is known to be responsible for ROS production in respiratory tract epithelial cells. Our aim was to clarify whether Duox1 was also involved in the PA-LPS-induced MUC5AC and calcium dependent chloride channel 3(Clca3), another recognized marker of goblet cell hyperplasia and mucus hyper-production.. PA-LPS-induced Duox1 mRNA levels were examined in A549 cells, primary mouse tracheal epithelial cells (mTECS) and lung tissues of mice. Nox inhibitors diphenyleneiodonium chloride (DPI) and Duox1 siRNA were used to investigate whether Duox1 is involved in PA-LPS-induced MUC5AC and Clca3 expression both in vitro and in vivo.. Duox1 is induced by PA-LPS in A549 cells, primary mTECs and lung tissues of mice. DPI significantly inhibited PA-LPS-induced up-regulation of Duox1, Muc5ac and Clca3 in primary mouse trachea epithelial cells and lung tissues of mice. Knockdown of Duox1 markedly inhibited PA-LPS-induced MUC5AC expression via a ROS-TGF-α cascade in A549 cells. Furthermore, DPI significantly inhibited PA-LPS-induced increases in inflammatory cells accumulated in mouse lungs.. We demonstrate for the first time that PA-LPS-induced MUC5AC and Clca3 expression is partly through Duox1, and provide supportive evidence for Duox1 as a potential target in treatments of mucin over-production diseases.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cell Line, Tumor; Chloride Channels; Dual Oxidases; Epithelial Cells; Gene Expression Regulation; Gene Knockdown Techniques; Humans; Lipopolysaccharides; Lung; Mice; Mucin 5AC; Mucoproteins; NADPH Oxidases; Onium Compounds; Pseudomonas aeruginosa; Reactive Oxygen Species; RNA, Small Interfering; Thiourea; Trachea; Transforming Growth Factor alpha

Foliar NH4(+) exposure is linked to inhibition of lateral root (LR) formation. Here, the role of shoot ethylene in NH4(+)-induced inhibition of LR formation in Arabidopsis was investigated using wild-type and mutant lines that show either blocked ethylene signalling (etr1) or enhanced ethylene synthesis (eto1, xbat32). NH4(+) exposure of wild-type Arabidopsis led to pronounced inhibition of LR production chiefly in the distal root, and triggered ethylene evolution and enhanced activity of the ethylene reporter EBS:GUS in the shoot. It is shown that shoot contact with NH4(+) is necessary to stimulate shoot ethylene evolution. The ethylene antagonists Ag(+) and aminoethoxyvinylglycine (AVG) mitigated LR inhibition under NH4(+) treatment. The decrease in LR production was significantly greater for eto1-1 and xbat32 and significantly less for etr1-3. Enhanced shoot ethylene synthesis/signalling blocked recovery of LR production when auxin was applied in the presence of NH4(+) and negatively impacted shoot AUX1 expression. The findings highlight the important role of shoot ethylene evolution in NH4(+)-mediated inhibition of LR formation.

Topics: Arabidopsis; Ethylenes; Glucuronidase; Indoleacetic Acids; Onium Compounds; Plant Roots; Plant Shoots; Quaternary Ammonium Compounds; Reactive Oxygen Species; Seedlings; Signal Transduction; Thiourea

Calmodulin (CaM), the predominant Ca(2+) receptors, is one of the best-characterized Ca(2+) sensors in all eukaryotes. In this study the role of CaM and the possible interrelationship between CaM and hydrogen peroxide (H(2)O(2)) in abscisic acid (ABA) induced antioxidant defense were investigated in the seedling of Panax ginseng. Treatment of ABA (100 μM) and H(2)O(2) (10 mM) increased the expression of Panax ginseng calmodulin gene (PgCaM) and significantly enhanced the expression of the antioxidant marker genes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase and the activities of chloroplastic and cytosolic antioxidant enzymes. Pretreatments with two CaM antagonists, trifluoperazine (TFP), N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide hydrochloride (W7) and inhibitor or scavenger, diphenyleneiodonium chloride, and dimethylthiourea of reactive oxygen species almost completely suppressed the up-regulation of antioxidant and PgCaM gene. Moreover, H(2)O(2) production and CaM content was almost completely inhibited by pretreatments with two CaM antagonists. In addition, the expressions of PgCaM gene under different biotic stress were analyzed at different time intervals. Thus it may suggests that CaM are involved in ABA-induced increased expression of PgCaM which triggers H(2)O(2) production through activating trans-plasma membrane NADPH oxidase, resulting in up-regulation of defense related antioxidant gene and also plays a pivotal role in defense response against pathogens.

Topics: Abscisic Acid; Antioxidants; Ascorbate Peroxidases; Calcium; Calmodulin; Glutathione Reductase; Hydrogen Peroxide; NADPH Oxidases; Onium Compounds; Panax; Reactive Oxygen Species; Seedlings; Sulfonamides; Superoxide Dismutase; Thiourea; Trifluoperazine

H(2)O(2), plasma membrane H(+)-ATPase (PM H(+)-ATPase) and salicylic acid (SA) play important roles in sensing external stimulation and activating defense responses in plants. However, it remains uncertain whether they are involved and interrelated in response to heat acclimation. Experiments were performed by pharmacological methods, and the relationship and the connection between endogenous H(2)O(2), free SA and PM H(+)-ATPase were investigated in pea plants (Pisum sativum L.) during heat acclimation. The results showed that an accumulation peaks of H(2)O(2), free SA and PM H(+)-ATPase, were detected during heat acclimation at 37 degrees C for 2 h and H(2)O(2) burst appeared before SA accumulation that followed by increase of PM H(+)-ATPase activity (Fig.1). Pretreatments with either scavengers of active oxygen species (dimethyl sulfoxide and ascorbic acid) or antioxidant (reduced glutathione) inhibited the increases in both H(2)O(2) and free SA contents as a part of heat acclimation (Fig.2). Additionally, changes in activity of plasma membrane NADPH oxidase paralleled with H(2)O(2) level during heat acclimation (Figs.1 and 3), implicating that H(2)O(2) might be generated by plasma membrane NADPH oxidase. Moreover, pretreatments with either diphenylene iodonium (DPI), a suicide substrate inhibitor of plasma membrane NADPH oxidase, or dimethylthiourea (DMTU), a quencher of H(2)O(2), could block the increase in free SA content and activity of plasma membrane NADPH oxidase as a part of heat acclimation (Fig.4). According to the assay described above, it is suggested that both H(2)O(2) and PM H(+)-ATPase participate in SA signaling that leads to the development of thermotolerance in pea plant, and H(2)O(2) functions upstream and PM H(+)-ATPase functions downstream of the SA signal. Also, the regulation mechanism of PM H(+)-ATPase activity was investigated, which showed that during heat acclimation, increase of PM H(+)-ATPase activity was independent of PM H(+)-ATPase amount and the enzyme activity may be modulated at post-translational level that may involve in reversible protein phosphorylation (Fig.5).

Topics: Cell Membrane; Hot Temperature; Hydrogen Peroxide; NADPH Oxidases; Onium Compounds; Pisum sativum; Plant Leaves; Proton-Translocating ATPases; Salicylic Acid; Signal Transduction; Thiourea