scholarly journals 611 High Temperature Acclimation and Catalase Stability in Pepper Leaves

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 502D-502
Author(s):  
Jeff Anderson
Keyword(s):  
Hydrogen Peroxide ◽  
Catalase Activity ◽  
Electrolyte Leakage ◽  
Inflection Point ◽  
Temperature Acclimation ◽  
Cellular Damage ◽  
Plant Responses ◽  
Stress Acclimation ◽  
Pepper Leaves ◽  
Leaf Disks

Activated forms of oxygen, including hydrogen peroxide, have been implicated in plant responses to stress. Environmental stresses may increase prooxidants, impair defense systems, or both. Stress acclimation may involve changes in capacity or stability of activated oxygen defenses. Catalases and peroxidases are the primary enzymatic detoxifiers of hydrogen peroxide in most plant tissues. Pepper leaf disks treated with hydrogen peroxide solutions from 0 to 100 mM showed increased electrolyte leakage and ethylene and methanol evolution with increasing concentration, but changes were slight compared to freeze-killed tissues. Data suggested that pepper leaves had considerable capacity to detoxify hydrogen peroxide. Cellular damage in heat-stressed tissues occurred over a similar temperature range that catalase activity declined. Leaf disks exposed to 24 to 59 °C for 15 min exhibited a sigmoidal electrolyte leakage response curve with an inflection at 51.5 °C. A similar plot of catalase activity vs. temperature exhibited an inflection point at 53.1 °C. Thermotolerance of plants exposed to the acclimating regime of 38 °C day/30 °C night increased from 50.7 to 53.9 °C based on electrolyte leakage. Catalase activity also showed an adaptive response with the inflection point increasing from 52.6 to 56.8 °C. It appears that catalase activity remains stable to a higher temperature in acclimated leaves, with similar activity in nonstressed control and acclimated plants.

scholarly journals Biocontrol Activity and Primed Systemic Resistance by Compost Water Extracts Against Anthracnoses of Pepper and Cucumber

2011 ◽  
Vol 101 (6) ◽  
pp. 732-740 ◽  
Author(s):  
Mee Kyung Sang ◽  
Ki Deok Kim
Keyword(s):  
Hydrogen Peroxide ◽  
Fungal Pathogens ◽  
Systemic Resistance ◽  
Plant Responses ◽  
Pr Genes ◽  
Water Extracts ◽  
Pepper Leaves ◽  
Related Enzyme ◽  
Hydrogen Peroxide Generation

We investigated direct and indirect effects of compost water extracts (CWEs) from Iljuk-3, Iljuk-7, Shinong-8, and Shinong-9 for the control of anthracnoses caused by Colletotrichum coccodes on pepper and C. orbiculare on cucumber. All tested CWEs significantly (P < 0.05) inhibited in vitro conidial germination and appressorium formation of the fungal pathogens; however, DL-β-amino-n-butyric acid (BABA) failed to inhibit the conidial development of the pathogens. Direct treatments of the CWEs and BABA on pepper and cucumber leaves at 1 and 3 days before or after inoculation significantly (P < 0.05) reduced anthracnose severities; Iljuk-3, Shinong-9, and BABA for pepper and Iljuk-7 for cucumber had more protective activities than curative activities. In addition, root treatment of CWEs suppressed anthracnoses on the plants by the pathogens; however, CWE treatment on lower leaves failed to reduce the diseases on the upper leaves of the plants. The CWE root treatments enhanced not only the expression of the pathogenesis-related (PR) genes CABPR1, CABGLU, CAChi2, CaPR-4, CAPO1, and CaPR-10 in pepper and PR1-1a, PR-2, PR-3, and APOX in cucumber but also the activity of β-1,3-glucanase, chitinase, and peroxidase and the generation of hydrogen peroxide in pepper and cucumber under pathogen-inoculated conditions. However, the CWE treatments failed to induce the plant responses under pathogen-free conditions. These results indicated that the CWEs had direct effects, reducing anthracnoses by C. coccodes on pepper leaves and C. orbiculare on cucumber leaves through protective and curative effects. In addition, CWE root treatments could induce systemic resistance in the primed state against pathogens on plant leaves that enhanced PR gene expression, defense-related enzyme production, and hydrogen peroxide generation rapidly and effectively immediately after pathogen infection. Thus, the CWEs might suppress anthracnoses on leaves of both pepper and cucumber through primed (priming-mediated) systemic resistance.

scholarly journals Protein Synthesis Inhibitors Block High-temperature Acclimation in Bell Pepper Leaves

HortScience ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 160-161 ◽  
Author(s):  
X. Liu ◽  
J.A. Anderson ◽  
N.O. Maness ◽  
B. Martin
Keyword(s):  
Protein Synthesis ◽  
High Temperature ◽  
Temperature Acclimation ◽  
Bell Pepper ◽  
Water Bath ◽  
Protein Synthesis Inhibitor ◽  
Distilled Water ◽  
Protein Synthesis Inhibitors ◽  
Pepper Leaves ◽  
Leaf Disks

Pepper (Capsicum annuum L. `Early Calwonder') leaf disks were vacuum-infiltrated in distilled water (control), anisomycin, aurintricarboxylic acid, cycloheximide, ethionine, norvanine, or puromycin to determine whether protein synthesis inhibitors blocked high-temperature acclimation. After infiltration, one-half of the leaf disks were placed in an incubator at 24C as a control, and the other half were kept in a water bath at 38C for 2 h to induce acclimation. Test tubes containing the disks then were placed in a water bath at 50.5C for 0, 1, 5, 10, 15, 25, 35, or 50 minutes. Thermotolerance was evaluated using electrolyte leakage. High-temperature acclimation was blocked in all six protein synthesis-inhibitor treatments. Only control disks infiltrated with distilled water acclimated. It seems that protein synthesis is required for high-temperature acclimation in bell pepper leaves.

scholarly journals High Temperature Acclimation in Pepper Leaves

HortScience ◽  
1990 ◽  
Vol 25 (10) ◽  
pp. 1272-1274 ◽  
Author(s):  
Jeffrey Anderson ◽  
Greg McCollum ◽  
Warren Roberts
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Response Curve ◽  
Temperature Acclimation ◽  
Stress Injury ◽  
Lethal Temperatures ◽  
Exposure Temperature ◽  
Pepper Leaves ◽  
Leaf Disks

Electrolyte leakage was used to quantify heat stress injury in `Early Calwonder' pepper (Capsicum annuum L.) leaf disks. Lethal temperatures were estimated from the midpoint of the sigmoidal response curve. An interaction between exposure temperature and duration was observed, with lethal temperatures decreasing linearly from 53 to 46C as exposure duration increased exponentially from 5 to 240 min. Exposure to two 7.5-min periods at 51.5C, interrupted by 4 hours at 21C, resulted in the same injury as a continuous 15-min exposure to 51.5C. Plants grown at 22/20C day/night cycles and held 24 hours at 38/30C had increased their heat tolerance by 3C, 51 to 54C; these plants reacclimated to 52C 48 hours after having been transferred back to 22/20C. Leaf disks acclimated significantly in vitro in 1 hour and were fully acclimated by 4 hours at 38C.

scholarly journals Microbial resistance in relation to catalase activity to oxidative stress induced by photolysis of hydrogen peroxide

2012 ◽  
Vol 56 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Keisuke Nakamura ◽  
Taro Kanno ◽  
Takayuki Mokudai ◽  
Atsuo Iwasawa ◽  
Yoshimi Niwano ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Catalase Activity ◽  
Microbial Resistance

Boron Supply and Water Deficit Consequences in Young Paricá (Schizolobium parahyba var. amazonicum) Plants

2016 ◽  
Vol 44 (1) ◽  
pp. 250-256 ◽  
Author(s):  
Bianca do Carmo SILVA ◽  
Pêola Reis de SOUZA ◽  
Daihany Moraes CALLEGARI ◽  
Vanessa Ferreira ALVES ◽  
Allan Klynger da Silva LOBATO ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Electrolyte Leakage ◽  
Tolerance Mechanism ◽  
Schizolobium Parahyba ◽  
Use Efficiency

Boron (B) is a very important nutrient required by forest plants; when supplied in adequate amounts, plants can ameliorate the negative effects of abiotic stresses. The objective of this study was to (i) investigate gas exchange, (ii) measure oxidant and antioxidant compounds, and (iii) respond how B supply acts on tolerance mechanism to water deficit in young Schizolobium parahyba plants. The experiment employed a factorial that was entirely randomised, with two boron levels (25 and 250 µmol L-1, simulating conditions of sufficient B and high B, respectively) and two water conditions (control and water deficit). Water deficit induced negative modifications on net photosynthetic rate, stomatal conductance and water use efficiency, while B high promoted intensification of the effects on stomatal conductance and water use efficiency. Hydrogen peroxide and electrolyte leakage of both tissues suffered non-significant increases after B high and when applied water deficit. Ascorbate levels presented increases after water deficit and B high to leaf and root. Our results suggested that the tolerance mechanism to water deficit in young Schizolobium parahyba plants is coupled to increases in total glutathione and ascorbate aiming to control the overproduction of hydrogen peroxide and alleviates the negative consequences on electrolyte leakage and gas exchange. In relation to B supply, this study proved that sufficient level promoted better responses under control and water deficit conditions.

scholarly journals Myeloperoxidase Modulates Hydrogen Peroxide Mediated Cellular Damage in Murine Macrophages

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1255
Author(s):  
Chaorui Guo ◽  
Inga Sileikaite ◽  
Michael J. Davies ◽  
Clare L. Hawkins
Keyword(s):  
Hydrogen Peroxide ◽  
Hypochlorous Acid ◽  
Cell Function ◽  
Inflammatory Diseases ◽  
Innate Immune ◽  
Cellular Damage ◽  
Enzymatic System ◽  
Therapeutic Approaches ◽  
Macrophage Cell

Myeloperoxidase (MPO) is involved in the development of many chronic inflammatory diseases, in addition to its key role in innate immune defenses. This is attributed to the excessive production of hypochlorous acid (HOCl) by MPO at inflammatory sites, which causes tissue damage. This has sparked wide interest in the development of therapeutic approaches to prevent HOCl-induced cellular damage including supplementation with thiocyanate (SCN−) as an alternative substrate for MPO. In this study, we used an enzymatic system composed of glucose oxidase (GO), glucose, and MPO in the absence and presence of SCN−, to investigate the effects of generating a continuous flux of oxidants on macrophage cell function. Our studies show the generation of hydrogen peroxide (H2O2) by glucose and GO results in a dose- and time-dependent decrease in metabolic activity and cell viability, and the activation of stress-related signaling pathways. Interestingly, these damaging effects were attenuated by the addition of MPO to form HOCl. Supplementation with SCN−, which favors the formation of hypothiocyanous acid, could reverse this effect. Addition of MPO also resulted in upregulation of the antioxidant gene, NAD(P)H:quinone acceptor oxidoreductase 1. This study provides new insights into the role of MPO in the modulation of macrophage function, which may be relevant to inflammatory pathologies.

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