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1.
José Gil-Longo Cristina González-Vázquez 《The Journal of nutritional biochemistry》2010,21(4):304-309
Gallic acid autoxidation was monitored by absorption spectroscopy and H2O2 production; vascular effects related to the autoxidation process were studied on intact and rubbed aortic rings from WKY rats. Gallic acid autoxidation in an oxygenated physiological salt solution (37°C, pH=7.4) mostly occurred in a 2-h time period. Superoxide anions, H2O2 and gallic acid quinones were produced during gallic acid autoxidation. In rings partially precontracted with phenylephrine, 0.1–3 μM gallic acid induced marked and largely endothelium-dependent contractions, 10–30 μM gallic acid induced endothelium-independent contractions and 0.1–0.3 mM gallic acid induced complete, fast-developing, endothelium-independent relaxations. Superoxide dismutase (SOD) shifted the endothelium-dependent gallic acid contractions to the right, and NG-nitro-l-arginine abolished them. Indomethacin suppressed the endothelium-independent gallic acid contractions, and catalase abolished the endothelium-independent contractions and relaxations. Gallic acid (30 μM) inhibited the relaxant effects of acetylcholine and sodium nitroprusside. In rings maximally precontracted with KCl, 0.1–100 μM gallic acid did not modify the tone, whereas 0.3 mM induced complete, slow-developing, endothelium-independent relaxations. Moreover, 0.3 mM gallic acid induced an irreversible impairment of ring reactivity and the release of lactate dehydrogenase. Catalase and N-acetyl cysteine suppressed the deleterious effects induced by gallic acid in the rings. In conclusion: (a) gallic acid is rapidly and nonenzymatically oxidized in physiological solutions, generating superoxide anions, H2O2 and quinones; (b) superoxide anions (by destroying NO) and low H2O2 levels (by activating cyclooxygenase) both increase vascular tone; (c) moderate H2O2 levels decrease vascular tone; (d) high H2O2 and quinone levels cause irreversible relaxations due to cellular damage. 相似文献
2.
Glucose transport by Hymenolepis diminuta was inhibited when Cl? in the bathing medium was replaced with acetate (C2H3O2Post?), but was unaffected when Cl? was replaced with SCN?. The relative effectiveness of the anions to inhibit influx of 7.4 mM Cl? in the presence of 1 mM glucose was SCN? > Cl? > C2H3O2Post?. Glucose stimulated the influxes of 120 mM Cl? and SCN?, but had little effect on 120 mM C2H3O2Post? influx. While the diffusion rates of the anions were C2H3O2Post? > SCN? = Cl?, the preference of the glucose transport system for the anions was SCN? > Cl? > C2H3O2Post?. Efflux of Cl? was not affected by the rate of glucose influx. Finally, microelectrode recordings of worms anesthetized with 2 mM arecoline revealed a transmembrane potential (TMP) of ?45 ± 3.6 mV (inside negative). Three to four minutes after addition of glucose (5 mM) there was a progressive hyperpolarization of the TMP to ?58 mV. A revised model of the glucose transport system that is consistent with previous observations on this organism is proposed. 相似文献
3.
LA Vasil'ev DB Kiselevsky EV Dzyubinskaya AV Nesov VD Samuilov 《Biochemistry. Biokhimii?a》2012,77(4):354-361
Tetraphenylphosphonium (TPP+) and tetramethylrhodamine ethyl ester (TMRE+) cations used as transmembrane carriers of ubiquinone (MitoQ) and plastoquinone (SkQ, SkQR) in mitochondria prevented at
nanomolar concentrations the chitosanor H2O2-induced destruction of the nucleus in epidermal cells of epidermis isolated from pea leaves. The protective effect of the
cations was potentiated by palmitate. Penetrating anions of tetraphenylboron (TB−) and phenyl dicarbaundecaborane also displayed protective effects at micromolar concentrations; the effect of TB− was potentiated by NH4Cl. It is proposed that the protective effect of the penetrating cations and anions against chitosan is due to suppression
of the generation of reactive oxygen species in mitochondria as a result of the protonophoric effect of the cations plus fatty
acids and the anions plus NH4+. Phenol was suitable as the electron donor for H2O2 reduction catalyzed by horseradish peroxidase, preventing the destruction of cell nuclei. The penetrating cations and anions,
SkQ1, and SkQR1 did not maintain the peroxidase or peroxidase/oxidase reactions measured by their suitability as electron
donors for H2O2 reduction or by the oxidation of exogenous NADH. 相似文献
4.
Superoxide anion and hydrogen peroxide production by chemically elicited peritoneal macrophages--induction by multiple nonphagocytic stimuli 总被引:19,自引:0,他引:19
The ability of a number of stimulants to activate an oxidative burst (OB) in oil-elicited guinea pig peritoneal exudate macrophages (MPs) was examined. The parameters of the OB were the generation and extracellular release of Superoxide anions (O2?) and hydrogen peroxide (H2O2). We found that: (1) The cocarcinogen and skin irritant phorbol myristate acetate (PMA) was the most potent OB activator—The weak cocarcinogen 4-O-methyl PMA was a proportionally less effective OB activator; (2) The lectins concanavalin A (Con A) and wheat germ agglutinin (WGA), but not soybean, Lotus, and pokeweed lectins, were also quite effective OB activators—The ability of Con A to stimulate O2? production was abolished by succinylation and could be prevented by the presence of α-methyl-D-mannoside; (3) Other stimulators of an OB in MPs were: N-formyl-methionyl peptides, opsonized zymosan, the Ca2+ ionophore A23187, phospholipase C, NaF, antimacrophage antibody, microtubule-disrupting drugs, and sodium nitroprusside—O2? generation induced by A23187 (but not that stimulated by PMA) was dependent on extracellular Ca2+; (4) The amount of O2? produced per cell was higher at low cell densities; (5) The addition of Superoxide dismutase (SOD) to the medium totally prevented the detection of O2? and augmented twice the amount of H2O2 recovered; (6) Pretreatment of MPs with the SOD inhibitor sodium diethyldithiocarbamate had no effect on the release of O2? but blocked H2O2 release in a dose-dependent manner. These data were interpreted as indicating that the bulk of H2O2 was derived by enzymatic dismutation of O2?; (7) The common mechanism by which such a variety of stimuli provoke an OB in MPs was not elucidated. No evidence was found to suggest a role for a cyclic nucleotide messenger. 相似文献
5.
A covalent core–shell structured protein cluster composed of hemoglobin (Hb) at the center and human serum albumins (HSA) at the periphery, Hb-HSAm, is an artificial O2 carrier that can function as a red blood cell substitute. Here we described the preparation of a novel Hb-HSA3 cluster with antioxidant activities and its O2 complex stable in aqueous H2O2 solution. We used an approach of incorporating a Pt nanoparticle (PtNP) into the exterior HSA unit of the cluster. A citrate reduced PtNP (1.8 nm diameter) was bound tightly within the cleft of free HSA with a binding constant (K) of 1.1×107 M−1, generating a stable HSA-PtNP complex. This platinated protein showed high catalytic activities for dismutations of superoxide radical anions (O2
•–) and hydrogen peroxide (H2O2), i.e., superoxide dismutase and catalase activities. Also, Hb-HSA3 captured PtNP into the external albumin unit (K = 1.1×107 M−1), yielding an Hb-HSA3(PtNP) cluster. The association of PtNP caused no alteration of the protein surface net charge and O2 binding affinity. The peripheral HSA-PtNP shell prevents oxidation of the core Hb, which enables the formation of an extremely stable O2 complex, even in H2O2 solution. 相似文献
6.
Previous studies have shown that hydrogen peroxide (H2O2) may mediate the auxin response during the formation of adventitious roots (AR). However, the mechanism and distribution of H2O2 during AR formation remains unclear. In this study, we investigate the spatiotemporal changes and role of H2O2 in AR initiation and development. Application of 5?C100 mM H2O2 to Mung bean (Phaseolus radiatus L.) hypocotyl cuttings induced AR formation in a dose-dependent manner. The effect was blocked by ascorbic acid (AA), an important reducing substrate for H2O2 reduction. Depletion of endogenous H2O2 by AA resulted in the significant reduction of AR emergence, suggesting a physiological role for H2O2 in the regulation of AR formation. Determination of H2O2 content showed that the level of H2O2 increased gradually and reached the highest value 60 h after induction of AR. Further detection of endogenous H2O2 by the specific fluorescent probe dichlorofluorescein diacetate (H2DCF-DA) and 3,3??-diaminobenzidine (DAB) staining in transverse sections of the basal region of cuttings revealed that obvious H2O2 signals were observed in the pericycle cells between the vascular bundles 24 h after the primary roots were removed. With the development of root primordia, H2O2 signals increased gradually and were mainly distributed in the root meristem. AA significant inhibited the H2O2-dependent fluorescence and the formation of AR, suggesting an essential role of H2O2 generation during AR initiation and development. Furthermore, the involvement of Ca2+ during H2O2-mediated AR formation was evaluated. Ca2+ channel inhibitors LaCl3 and ruthenium red (RR) and Ca2+ chelator ethylene glycol-bis(2-aminoethylether)-N,N,N??,N??-tetraacetic acid (EGTA) prevent H2O2-induced AR formation, which indicate that the hypocotyl cuttings response to H2O2 depends on the availability of both intracellular and extracellular Ca2+ pools, and Ca2+ is a downstream messenger in the signaling pathway triggered by H2O2 to promote adventitious root formation. 相似文献
7.
《Inorganica chimica acta》2006,359(9):2721-2727
Salts of the new complexes [PW11O39{Rh2(O2CR)2}]5−; R = Prn (1), CH2Cl (2), CH2OH (3), o-C6H4OH (4), p-C6H4OH (5), and [XW11O39{Rh2(p-O2CC6H4OH)2}]6−; X = Si (6), Ge (7) have been prepared in good yield and characterized by elemental analysis, multinuclear NMR spectroscopy, and structural crystallography of the cesium salts of anions 1 and 5 with chloride ions in axial positions of the dirhodium moiety. The incorporation of the dirhodium group into the Keggin structure significantly increases the hydrolytic kinetic stability of the polyoxotungstates at pH 7–8.5, a result that has implications for the use of such complexes for imaging and for phase determination in structural studies of large biomolecules. Based on NMR studies, the axial sites of the dirhodium moiety of the polytungstate anions are accessible to ligation by molecules such as cysteine, methionine, and isonicotinic acid. 相似文献
8.
Nobutoshi Ichise Naoki Morita Tamotsu Hoshino Kosei Kawasaki Isao Yumoto Hidetoshi Okuyama 《Applied microbiology》1999,65(1):73-79
A possible mechanism of resistance to hydrogen peroxide (H2O2) in Vibrio rumoiensis, isolated from the H2O2-rich drain pool of a fish processing plant, was examined. When V. rumoiensis cells were inoculated into medium containing either 5 mM or no H2O2, they grew in similar manners. A spontaneous mutant strain, S-4, derived from V. rumoiensis and lacking catalase activity did not grow at all in the presence of 5 mM H2O2. These results suggest that catalase is inevitably involved in the resistance and survival of V. rumoiensis in the presence of H2O2. Catalase activity was constitutively present in V. rumoiensis cells grown in the absence of H2O2, and its occurrence was dependent on the age of the cells, a characteristic which is observed for the HP II-type catalase of Escherichia coli. The presence of the HP II-type catalase in V. rumoiensis cells was evidenced by partial sequencing of the gene encoding the HP II-type catalase from this organism. A notable difference between V. rumoiensis and E. coli is that catalase is accumulated at very high levels (~2% of the total soluble proteins) in V. rumoiensis, in contrast to the case for E. coli. When V. rumoiensis cells which had been exposed to 5 mM H2O2 were centrifuged, most intracellular proteins, including catalase, were recovered in the medium. On the other hand, when V. rumoiensis cells were grown on plates containing various concentrations of H2O2, individual cells had a colony-forming ability inferior to those of E. coli, Bacillus subtilis, and Vibrio parahaemolyticus. Thus, it is suggested that when V. rumoiensis cells are exposed to high concentrations of H2O2, most cells will immediately be broken by H2O2. In addition, the cells which have had little or no damage will start to grow in a medium where almost all H2O2 has been decomposed by the catalase released from broken cells. 相似文献
9.
10.
Vanderlei Folmer Nuno Pedroso Sílvia C.D.N. Lopes Luísa Cyrne 《生物化学与生物物理学报:生物膜》2008,1778(4):1141-1147
In Saccharomyces cerevisiae, the diffusion rate of hydrogen peroxide (H2O2) through the plasma membrane decreases during adaptation to H2O2 by means of a mechanism that is still unknown. Here, evidence is presented that during adaptation to H2O2 the anisotropy of the plasma membrane increases. Adaptation to H2O2 was studied at several times (15min up to 90min) by applying the steady-state H2O2 delivery model. For wild-type cells, the steady-state fluorescence anisotropy increased after 30min, or 60min, when using 2-(9-anthroyloxy) stearic acid (2-AS), or diphenylhexatriene (DPH) membrane probe, respectively. Moreover, a 40% decrease in plasma membrane permeability to H2O2 was observed at 15min with a concomitant two-fold increase in catalase activity. Disruption of the ergosterol pathway, by knocking out either ERG3 or ERG6, prevents the changes in anisotropy during H2O2 adaptation. H2O2 diffusion through the plasma membrane in S. cerevisiae cells is not mediated by aquaporins since the H2O2 permeability constant is not altered in the presence of the aquaporin inhibitor mercuric chloride. Altogether, these results indicate that the regulation of the plasma membrane permeability towards H2O2 is mediated by modulation of the biophysical properties of the plasma membrane. 相似文献
11.
Karine Salin Sonya K. Auer Agata M. Rudolf Graeme J. Anderson Andrew G. Cairns William Mullen Richard C. Hartley Colin Selman Neil B. Metcalfe 《Biology letters》2015,11(9)
There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2
in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical environmental conditions and nutritional states. Interindividual variation in H2O2 content was unrelated to mitochondrial density but was significantly associated with SMR: fish with a higher mass-independent SMR had a lower level of H2O2. The mechanism underlying this observed relationship between SMR and in vivo H2O2 content requires further investigation, but may implicate mitochondrial uncoupling which can simultaneously increase SMR but reduce ROS production. To our knowledge, this is the first study in living organisms to show that individuals with higher oxygen consumption rates can actually have lower levels of H2O2. 相似文献
12.
Rachel E. Pritchard Alexandre J. Prassinos John D. Osborne Ziv Raviv Mitchell F. Balish 《PloS one》2014,9(8)
Mycoplasma iowae is a well-established avian pathogen that can infect and damage many sites throughout the body. One potential mediator of cellular damage by mycoplasmas is the production of H2O2 via a glycerol catabolic pathway whose genes are widespread amongst many mycoplasma species. Previous sequencing of M. iowae serovar I strain 695 revealed the presence of not only genes for H2O2 production through glycerol catabolism but also the first documented mycoplasma gene for catalase, which degrades H2O2. To test the activity of M. iowae catalase in degrading H2O2, we studied catalase activity and H2O2 accumulation by both M. iowae serovar K strain DK-CPA, whose genome we sequenced, and strains of the H2O2-producing species Mycoplasma gallisepticum engineered to produce M. iowae catalase by transformation with the M. iowae putative catalase gene, katE. H2O2-mediated virulence by M. iowae serovar K and catalase-producing M. gallisepticum transformants were also analyzed using a Caenorhabditis elegans toxicity assay, which has never previously been used in conjunction with mycoplasmas. We found that M. iowae katE encodes an active catalase that, when expressed in M. gallisepticum, reduces both the amount of H2O2 produced and the amount of damage to C. elegans in the presence of glycerol. Therefore, the correlation between the presence of glycerol catabolism genes and the use of H2O2 as a virulence factor by mycoplasmas might not be absolute. 相似文献
13.
Fei Ma Lijuan Wang Jiale Li Muhammad Kaleem Samma Yanjie Xie Ren Wang Jin Wang Jing Zhang Wenbiao Shen 《Plant molecular biology》2014,85(1-2):49-61
Haem oxygenase-1 (HO-1) and hydrogen peroxide (H2O2) are two key downstream signals of auxin, a well-known phytohormone regulating plant growth and development. However, the inter-relationship between HO-1 and H2O2 in auxin-mediated lateral root (LR) formation is poorly understood. Herein, we revealed that exogenous auxin, 1-naphthylacetic acid (NAA), could simultaneously stimulate Arabidopsis HO-1 (HY1) gene expression and H2O2 generation. Subsequently, LR formation was induced. NAA-induced HY1 expression is dependent on H2O2. This conclusion was supported by analyzing the removal of H2O2 with ascorbic acid (AsA) and dimethylthiourea (DMTU), both of which could block NAA-induced HY1 expression and LR formation. H2O2-induced LR formation was inhibited by an HO-1 inhibitor zinc protoporphyrin IX (Znpp) in wild-type and severely impaired in HY1 mutant hy1-100. Simultaneously, HY1 is required for NAA-mediated H2O2 generation, since Znpp inhibition of HY1 blocked the NAA-induced H2O2 production and LR formation. Genetic data demonstrated that hy1-100 was significantly impaired in H2O2 production and LR formation in response to NAA, compared with wild-type plants. The addition of carbon monoxide-releasing molecule-2 (CORM-2), the carbon monoxide (CO) donor, induced H2O2 production and LR formation, both of which were decreased by DMTU. Moreover, H2O2 and CORM-2 mimicked the NAA responses in the regulation of cell cycle genes expression, all of which were blocked by Znpp or DMTU, respectively, confirming that both H2O2 and CO were important in the early LR initiation. In summary, our pharmacological, genetic and molecular evidence demonstrated a close inter-relationship between HY1 and H2O2 existing in auxin-induced LR formation in Arabidopsis. 相似文献
14.
Background and Aims In photosynthetic organisms exposure to high light induces the production of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), which in part is prevented by non-photochemical quenching (NPQ). As one of the most stable and longest-lived ROS, H2O2 is involved in key signalling pathways in development and stress responses, although in excess it can induce damage. A ubiquitous response to high light is the induction of the xanthophyll cycle, but its role in algae is unclear as it is not always associated with NPQ induction. The aim of this study was to reveal how diurnal changes in the level of H2O2 are regulated in a freshwater algal community.Methods A natural freshwater community of algae in a temporary rainwater pool was studied, comprising photosynthetic Euglena species, benthic Navicula diatoms, Chlamydomonas and Chlorella species. Diurnal measurements were made of photosynthetic performance, concentrations of photosynthetic pigments and H2O2. The frequently studied model organisms Chlamydomonas and Chlorella species were isolated to study photosynthesis-related H2O2 responses to high light.Key Results NPQ was shown to prevent H2O2 release in Chlamydomonas and Chlorella species under high light; in addition, dissolved organic carbon excited by UV-B radiation was probably responsible for a part of the H2O2 produced in the water column. Concentrations of H2O2 peaked at 2 µm at midday and algae rapidly scavenged H2O2 rather than releasing it. A vertical H2O2 gradient was observed that was lowest next to diatom-rich benthic algal mats. The diurnal changes in photosynthetic pigments included the violaxanthin and diadinoxanthin cycles; the former was induced prior to the latter, but neither was strictly correlated with NPQ.Conclusions The diurnal cycling of H2O2 was apparently modulated by the organisms in this freshwater algal community. Although the community showed flexibility in its levels of NPQ, the diurnal changes in xanthophylls correlated with H2O2 concentrations. Alternative NPQ mechanisms in algae involving proteins of the light-harvesting complex type and antioxidant protection of the thylakoid membrane by de-epoxidized carotenoids are discussed. 相似文献
15.
M Torres C Auclair J Hakim 《Biochemical and biophysical research communications》1979,88(3):1003-1009
The granule rich-fraction isolated from human resting polymorphonuclear leukocytes is capable of CN-insensitive NADH oxidation and O2-uptake, accompanied by production of superoxide anion, hydroxyl radicals and H2O2. We showed that H2O2 initiates and maintains NADH oxidation and O2-uptake but is also necessary for the formation of superoxide anion and hydroxyl radicals. It acts as a primary substrate for CN-insensitive protein-mediated formation of hydroxyl radicals, which in turn produce superoxide anions, probably through univalent oxidation of NADH as an intermediary. 相似文献
16.
Various forms of stress result in decreased O2 permeability or decreased capacity to consume O2 in legume root nodules. These changes alter the nodule interior O2 concentration (Oi). To determine the relationship between Oi and nitrogenase activity in attached soybean (Glycine max) nodules, we controlled Oi by varying external pO2 while monitoring internal H2 concentration (Hi) with microelectrodes. Oi was monitored by noninvasive leghemoglobin spectrophotometry (nodule oximetry). After each step-change in Oi, Hi approached a new steady state, with a time constant averaging 23 s. The rate of H2 production by nitrogenase was calculated as the product of Hi, nodule surface area, and nodule H2 permeability. H2 permeability was estimated from O2 permeability (measured by nodule oximetry) by assuming diffusion through air-filled pores; support for this assumption is presented. Oi was nearly optimal for nitrogenase activity (H2 production) between 15 and 150 nm. A 1- to 2-min exposure to elevated external pO2 (40-100 kPa) reduced Hi to zero, but nitrogenase activity recovered quickly under air, often in <20 min. This rapid recovery contrasts with previous reports of much slower recovery with longer exposures to elevated pO2. The mechanism of nitrogenase inhibition may differ between brief and prolonged O2 exposures. 相似文献
17.
The involvement of hydrogen peroxide in the differentiation of secondary walls in cotton fibers 总被引:34,自引:1,他引:33
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H2O2 is a widespread molecule in many biological systems. It is created enzymatically in living cells during various oxidation reactions and by leakage of electrons from the electron transport chains. Depending on the concentration H2O2 can induce cell protective responses, programmed cell death, or necrosis. Here we provide evidence that H2O2 may function as a developmental signal in the differentiation of secondary walls in cotton (Gossypium hirsutum) fibers. Three lines of evidence support this conclusion: (a) the period of H2O2 generation coincided with the onset of secondary wall deposition, (b) inhibition of H2O2 production or scavenging the available H2O2 from the system prevented the wall differentiation process, and (c) exogenous addition of H2O2 prematurely promoted secondary wall formation in young fibers. Furthermore, we provide support for the concept that H2O2 generation could be mediated by the expression of the small GTPase Rac, the accumulation of which was shown previously to be strongly induced during the onset of secondary wall differentiation. In support of Rac's role in the activation of NADPH oxidase and the generation of reactive oxygen species, we transformed soybean (Glycine max) and Arabidopsis cells with mutated Rac genes. Transformation with a dominantly activated cotton Rac13 gene resulted in constitutively higher levels of H2O2, whereas transformation with the antisense and especially with dominant-negative Rac constructs decreased the levels of H2O2. 相似文献
18.
Rachel Benisty Aharon Yehonatan Cohen Alexandra Feldman Zvi Cohen Nurith Porat 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2010,1801(9):1098-1104
FabF elongation condensing enzyme is a critical factor in determining the spectrum of products produced by the FASII pathway. Its active site contains a critical cysteine-thiol residue, which is a plausible target for oxidation by H2O2. Streptococcus pneumoniae produces exceptionally high levels of H2O2, mainly through the conversion of pyruvate to acetyl-P via pyruvate oxidase (SpxB). We present evidence showing that endogenous H2O2 inhibits FabF activity by specifically oxidizing its active site cysteine-thiol residue. Thiol trapping methods revealed that one of the three FabF cysteines in the wild-type strain was oxidized, whereas in an spxB mutant, defective in H2O2 production, none of the cysteines was oxidized, indicating that the difference in FabF redox state originated from endogenous H2O2. In vitro exposure of the spxB mutant to various H2O2 concentrations further confirmed that only one cysteine residue was susceptible to oxidation. By blocking FabF active site cysteine with cerulenin we show that the oxidized cysteine was the catalytic one. Inhibition of FabF activity by either H2O2 or cerulenin resulted in altered membrane fatty acid composition. We conclude that FabF activity is inhibited by H2O2 produced by S. pneumoniae. 相似文献
19.
Ji Young Jang Ji Ye Rhee Gap Chae Chung Hunseung Kang 《Plant signaling & behavior》2012,7(9):1180-1181
Hydrogen peroxide (H2O2) is a reactive oxygen species that signals between cells, and H2O2 signaling is essential for diverse cellular processes, including stress response, defense against pathogens, and the regulation of programmed cell death in plants. Although plasma membrane intrinsic proteins (PIPs) have been known to transport H2O2 across cell membranes, the permeability of each family member of PIPs toward H2O2 has not yet been determined in most plant species. In a recent study, we showed that certain isoforms of Arabidopsis thaliana AtPIPs, including AtPIP2;2, AtPIP2;4, AtPIP2;5, and AtPIP2;7, are permeable for H2O2 in yeast cells. Since the expression of PIPs is differently modulated in Arabidopsis by abiotic stress or H2O2 treatment, it is important to investigate the integrated regulation of aquaporin expression and their physiological significance in H2O2 transport and plant response to diverse abiotic stresses. 相似文献
20.
Justus Niemeyer David Scheuring Julian Oestreicher Bruce Morgan Michael Schroda 《The Plant cell》2021,33(9):2935
Hydrogen peroxide (H2O2) is recognized as an important signaling molecule in plants. We sought to establish a genetically encoded, fluorescent H2O2 sensor that allows H2O2 monitoring in all major subcompartments of a Chlamydomonas cell. To this end, we used the Chlamydomonas Modular Cloning toolbox to target the hypersensitive H2O2 sensor reduction–oxidation sensitive green fluorescent protein2-Tsa2ΔCR to the cytosol, nucleus, mitochondrial matrix, chloroplast stroma, thylakoid lumen, and endoplasmic reticulum (ER). The sensor was functional in all compartments, except for the ER where it was fully oxidized. Employing our novel sensors, we show that H2O2 produced by photosynthetic linear electron transport (PET) in the stroma leaks into the cytosol but only reaches other subcellular compartments if produced under nonphysiological conditions. Furthermore, in heat-stressed cells, we show that cytosolic H2O2 levels closely mirror temperature up- and downshifts and are independent from PET. Heat stress led to similar up- and downshifts of H2O2 levels in the nucleus and, more mildly, in mitochondria but not in the chloroplast. Our results thus suggest the establishment of steep intracellular H2O2 gradients under normal physiological conditions with limited diffusion into other compartments. We anticipate that these sensors will greatly facilitate future investigations of H2O2 biology in plant cells.The establishment of a hypersensitive H2O2 sensor in six major compartments of the Chlamydomonas cell reveals steep intracellular H2O2 gradients under normal physiological conditions with limited diffusion into other compartments. 相似文献