Ozone Sensitivity
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Environmental stress sensitivity of an ascorbic acid-deficient Arabidopsis mutant.
L-ascorbic acid (vitamin C) is a powerful reducing agent found in millimolar concentrations in plants, and is proposed to play an important role in scavenging free radicals in plants and animals. However, surprisingly little is known about the role of this antioxidant in plant environmental stress adaptation or ascorbate biosynthesis. We report the isolation
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14. Long-Term Dosimetry of Solar UV Radiation in Antarctica with Spores of Bacillus subtilis
The main objective was to assess the influence of the seasonal stratospheric ozone depletion on the UV climate in Antarctica by using a biological test system. This method is based on the UV sensitivity of a DNA repair-deficient strain of Bacillus subtilis (TKJ 6321). In our field experiment, dried layers of B. subtilis spores on quartz discs were exposed in
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15. Jasmonic Acid Signaling Modulates Ozone-Induced Hypersensitive Cell Death
Recent studies suggest that cross-talk between salicylic acid (SA)–, jasmonic acid (JA)–, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O3) exposure activates a hypersensitive response (HR)–like cell death pathway in the Arabidopsis ecotype Cvi-0.
American Society of Plant Physiologists.
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16. Comparison of animal infectivity, excystation, and fluorogenic dye as measures of Giardia muris cyst inactivation by ozone.
Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6.7, 22 degrees C) in ozone-demand-free phosphate buffer. There was a significant difference between fluoro
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17. Ethylene Insensitivity Modulates Ozone-Induced Cell Death in Birch1
We have used genotypic variation in birch (Betula pendula Roth) to investigate the roles of ozone (O3)-induced ethylene (ET), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to O3. Of these hormones, ET evolution correlated best with O3-induced cell death. Disruption of ET perception by transformation of birch with the dominant negati
American Society of Plant Biologists.
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18. Arabidopsis HARMLESS TO OZONE LAYER Protein Methylates a Glucosinolate Breakdown Product and Functions in Resistance to Pseudomonas syringae pv. maculicola*
Almost all of the chlorine-containing gas emitted from natural sources is methyl chloride (CH3Cl), which contributes to the destruction of the stratospheric ozone layer. Tropical and subtropical plants emit substantial amounts of CH3Cl. A gene involved in CH3Cl emission from Arabidopsis was previously identified and designated HARMLESS TO OZONE LAYER (hereaf
American Society for Biochemistry and Molecular Biology.
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19. The Wavelengths in Sunlight Effective in Producing Skin Cancer: A Theoretical Analysis
DNA is taken as the target for skin cancer induced by ultraviolet light, and the known data on the sensitivity of DNA as a function of wavelength are summarized. The sun's spectrum at the surface of the earth and the DNA action spectrum are used to calculate the carcinogenic effectiveness as a function of wavelength. The most effective wavelengths at 30°N l
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20. Arabidopsis Flavonoid Mutants Are Hypersensitive to UV-B Irradiation.
Increases in the terrestrial levels of ultraviolet-B (UV-B) radiation (280 to 320 nm) due to diminished stratospheric ozone have prompted an investigation of the protective mechanisms that contribute to UV-B tolerance in plants. In response to UV-B stress, flowering plants produce a variety of UV-absorptive secondary products derived from phenylalanine. Arab
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21. Arabidopsis RADICAL-INDUCED CELL DEATH1 Belongs to the WWE Protein–Protein Interaction Domain Protein Family and Modulates Abscisic Acid, Ethylene, and Methyl Jasmonate Responses
Experiments with several Arabidopsis thaliana mutants have revealed a web of interactions between hormonal signaling. Here, we show that the Arabidopsis mutant radical-induced cell death1 (rcd1), although hypersensitive to apoplastic superoxide and ozone, is more resistant to chloroplastic superoxide formation, exhibits reduced sensitivity to abscisic acid,
American Society of Plant Biologists.
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22. A Methyl Viologen-Resistant Mutant of Arabidopsis, Which Is Allelic to Ozone-Sensitive rcd1, Is Tolerant to Supplemental Ultraviolet-B Irradiation1
To better understand the role of active oxygen species (AOS) in acquired resistance to increased levels of ultraviolet (UV)-B irradiation in plants, we isolated an Arabidopsis mutant that is resistant to methyl viologen, and its sensitivity to UV-B was investigated. A complementation test revealed that the obtained mutant was allelic to the ozone-sensitive r
The American Society for Plant Biologists.
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23. Arabidopsis cyt1 mutants are deficient in a mannose-1-phosphate guanylyltransferase and point to a requirement of N-linked glycosylation for cellulose biosynthesis
Arabidopsis cyt1 mutants have a complex phenotype indicative of a severe defect in cell wall biogenesis. Mutant embryos arrest as wide, heart-shaped structures characterized by ectopic accumulation of callose and the occurrence of incomplete cell walls. Texture and thickness of the cell walls are irregular, and unesterified pectins show an abnormally di
The National Academy of Sciences.
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24. Induction of bronchial hypersensitivity: evidence for a role for prostaglandins.
Bronchial hyper-responsiveness is a particular feature of asthma, but also occurs in normal subjects after a viral upper respiratory tract infection or ozone inhalation. Such stimuli would be expected to result in the release of chemical mediators of inflammation. In this study, the effects of one of these, prostaglandin F2 alpha (PGF2 alpha), on the respons