51
|
Götz M, Albert A, Stich S, Heller W, Scherb H, Krins A, Langebartels C, Seidlitz HK, Ernst D. PAR modulation of the UV-dependent levels of flavonoid metabolites in Arabidopsis thaliana (L.) Heynh. leaf rosettes: cumulative effects after a whole vegetative growth period. PROTOPLASMA 2010; 243:95-103. [PMID: 19669863 DOI: 10.1007/s00709-009-0064-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 07/13/2009] [Indexed: 05/20/2023]
Abstract
Long-term effects of ultraviolet (UV) radiation on flavonoid biosynthesis were investigated in Arabidopsis thaliana using the sun simulators of the Helmholtz Zentrum München. The plants, which are widely used as a model system, were grown (1) at high photosynthetically active radiation (PAR; 1,310 micromol m(-2) s(-1)) and high biologically effective UV irradiation (UV-B(BE) 180 mW m(-2)) during a whole vegetative growth period. Under this irradiation regime, the levels of quercetin products were distinctively elevated with increasing UV-B irradiance. (2) Cultivation at high PAR (1,270 micromol m(-2) s(-1)) and low UV-B (UV-B(BE) 25 mW m(-2)) resulted in somewhat lower levels of quercetin products compared to the high-UV-B(BE) conditions, and only a slight increase with increasing UV-B irradiance was observed. On the other hand, when the plants were grown (3) at low PAR (540 micromol m(-2) s(-1)) and high UV-B (UV-B(BE) 180 mW m(-2)), the accumulation of quercetin products strongly increased from very low levels with increasing amounts of UV-B but the accumulation of kaempferol derivatives and sinapoyl glucose was less pronounced. We conclude (4) that the accumulation of quercetin products triggered by PAR leads to a basic UV protection that is further increased by UV-B radiation. Based on our data, (5) a combined effect of PAR and different spectral sections of UV radiation is satisfactorily described by a biological weighting function, which again emphasizes the additional role of UV-A (315-400 nm) in UV action on A. thaliana.
Collapse
Affiliation(s)
- Michael Götz
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
52
|
Xu J, Gao K. Use of UV-A energy for photosynthesis in the red macroalga Gracilaria lemaneiformis. Photochem Photobiol 2010; 86:580-5. [PMID: 20202161 DOI: 10.1111/j.1751-1097.2010.00709.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
UV radiation is known to inhibit photosynthetically active radiation (PAR)-driven photosynthesis; however, moderate levels of UV-A have been shown to enhance photosynthesis and growth rates of some algae. Here, we have shown that UV-A alone could drive photosynthetic utilization of bicarbonate in the red alga Gracilaria lemaneiformis as evidenced in either O(2) evolution or carbon fixation as well as pH drift. Addition of UV-B inhibited the apparent photosynthetic efficiency, raised the photosynthetic compensation point and photosynthesis-saturating irradiance level, but did not significantly affect the maximal rate of photosynthetic O(2) evolution. The electron transport inhibitor, DCMU, inhibited the photosynthesis completely, reflecting that energy of UV-A was transferred in the same way as that of PAR. Inorganic carbon acquisition for photosynthesis under UV alone was inhibited by the inhibitors of carbonic anhydrase. The results provided the evidence that G. lemaneiformis can use UV-A efficiently to drive photosynthesis based on the utilization of bicarbonate, which could contribute significantly to the enhanced photosynthesis in the presence of UV-A observed under reduced levels of solar radiation.
Collapse
Affiliation(s)
- Juntian Xu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | | |
Collapse
|
53
|
Guan W, Gao K. Enhanced calcification ameliorates the negative effects of UV radiation on photosynthesis in the calcifying phytoplankter Emiliania huxleyi. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-0042-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
54
|
Wu Y, Gao K, Li G, Walter Helbling E. Seasonal Impacts of Solar UV Radiation on Photosynthesis of Phytoplankton Assemblages in the Coastal Waters of the South China Sea. Photochem Photobiol 2010; 86:586-92. [DOI: 10.1111/j.1751-1097.2009.00694.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
55
|
Detection of Multidecadal Changes in UVB and Total Ozone Concentrations over the Continental US with NASA TOMS Data and USDA Ground-Based Measurements. REMOTE SENSING 2010. [DOI: 10.3390/rs2010262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
56
|
Xu Z, Gao K. Impacts of UV radiation on growth and photosynthetic carbon acquisition in Gracilaria lemaneiformis (Rhodophyta) under phosphorus-limited and replete conditions. FUNCTIONAL PLANT BIOLOGY : FPB 2010; 36:1057-1064. [PMID: 32688717 DOI: 10.1071/fp09092] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 07/24/2009] [Indexed: 06/11/2023]
Abstract
Solar ultraviolet radiation (UVR, 280-400 nm) is known to negatively affect macroalgal growth and photosynthesis, while phosphorus availability may affect their sensitivity to UVR. Here, we show that UV-A enhanced the growth rate of the red macroalga, Gracilaria lemaneiformis Bory de Saint-Vincent under inorganic phosphorus (Pi)-replete but reduced it under Pi-limited conditions. Maximal net photosynthetic rates were significantly reduced by both UV-A and UV-B, but the apparent photosynthetic efficiency was enhanced in the presence of UV-A. The UV-induced inhibition was exacerbated under Pi-limited conditions. The activity of total carbonic anhydrase was enhanced and the photosynthetic affinity for exogenous inorganic carbon (Ci) was raised for thalli grown in the presence of UVR under both Pi-replete and Pi-limited conditions. The relative growth rate was closely related to Ci acquisition capability (Vmax/KDIC), which was enhanced by UVR exposure under Pi-replete but not significantly affected under Pi-limited conditions.
Collapse
Affiliation(s)
- Zhiguang Xu
- Marine Biology Institute, Shantou University, Shantou, Guangdong 515063, China
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
57
|
Polar firn air reveals large-scale impact of anthropogenic mercury emissions during the 1970s. Proc Natl Acad Sci U S A 2009; 106:16114-9. [PMID: 19805267 DOI: 10.1073/pnas.0905117106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mercury (Hg) is an extremely toxic pollutant, and its biogeochemical cycle has been perturbed by anthropogenic emissions during recent centuries. In the atmosphere, gaseous elemental mercury (GEM; Hg degrees ) is the predominant form of mercury (up to 95%). Here we report the evolution of atmospheric levels of GEM in mid- to high-northern latitudes inferred from the interstitial air of firn (perennial snowpack) at Summit, Greenland. GEM concentrations increased rapidly after World War II from approximately 1.5 ng m(-3) reaching a maximum of approximately 3 ng m(-3) around 1970 and decreased until stabilizing at approximately 1.7 ng m(-3) around 1995. This reconstruction reproduces real-time measurements available from the Arctic since 1995 and exhibits the same general trend observed in Europe since 1990. Anthropogenic emissions caused a two-fold rise in boreal atmospheric GEM concentrations before the 1970s, which likely contributed to higher deposition of mercury in both industrialized and remotes areas. Once deposited, this toxin becomes available for methylation and, subsequently, the contamination of ecosystems. Implementation of air pollution regulations, however, enabled a large-scale decline in atmospheric mercury levels during the 1980s. The results shown here suggest that potential increases in emissions in the coming decades could have a similar large-scale impact on atmospheric Hg levels.
Collapse
|
58
|
Angell JK, Free M. Ground‐based observations of the slowdown in ozone decline and onset of ozone increase. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd010860] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
59
|
Franz J, Francisco JS, Peyerimhoff SD. Production of singlet oxygen atoms by photodissociation of oxywater. J Chem Phys 2009; 130:084304. [PMID: 19256608 DOI: 10.1063/1.3080808] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum chemical calculations are reported for the energies of the few lowest electronic singlet states of oxywater along dissociation of the oxygen-oxygen bond into water and singlet oxygen using multistate multireference second-order Moller-Plesset perturbation theory. We compute an energy of 21 kcal/mol to remove one oxygen atom in the lowest singlet state. The two lowest excited singlet states have vertical excitation energies of 2.64 and 2.96 eV (470 and 419 nm) and are leading to the dissociation of the molecule. The two charge transfer states are accessible at vertical excitation of 4.91 and 5.22 eV (253 and 238 nm).
Collapse
Affiliation(s)
- Jan Franz
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom.
| | | | | |
Collapse
|
60
|
Yang ES, Cunnold DM, Newchurch MJ, Salawitch RJ, McCormick MP, Russell JM, Zawodny JM, Oltmans SJ. First stage of Antarctic ozone recovery. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009675] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
61
|
Ray R, Agrawal N, Sharma A, Hans R. Use of L-929 cell line for phototoxicity assessment. Toxicol In Vitro 2008; 22:1775-81. [DOI: 10.1016/j.tiv.2008.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 04/17/2008] [Accepted: 06/05/2008] [Indexed: 10/21/2022]
|
62
|
Lopez-Martinez G, Elnitsky MA, Benoit JB, Lee RE, Denlinger DL. High resistance to oxidative damage in the Antarctic midge Belgica antarctica, and developmentally linked expression of genes encoding superoxide dismutase, catalase and heat shock proteins. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2008; 38:796-804. [PMID: 18625403 DOI: 10.1016/j.ibmb.2008.05.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 05/13/2008] [Accepted: 05/18/2008] [Indexed: 05/26/2023]
Abstract
Intense ultraviolet radiation, coupled with frequent bouts of freezing-thawing and anoxia, have the potential to generate high levels of oxidative stress in Antarctic organisms. In this study, we examined mechanisms used by the Antarctic midge, Belgica antarctica, to counter oxidative stress. We cloned genes encoding two key antioxidant enzymes, superoxide dismutase (SOD) and catalase (Cat), and showed that SOD mRNA was expressed continuously and at very high levels in larvae, but not in adults, while Cat mRNA was expressed in both larvae and adults but at a somewhat reduced level. SOD mRNA was expressed at even higher levels in larvae that were exposed to direct sunlight. Catalase, a small heat shock protein, Hsp70 and Hsp90 mRNAs were also strongly upregulated in response to sunlight. Total antioxidant capacity of the adults was higher than that of the larvae, but levels in both stages of the midge were much higher than observed in a freeze-tolerant, temperate zone insect, the gall fly Eurosta solidaginis. Assays to measure oxidative damage (lipid peroxidation TBARS and carbonyl proteins) demonstrated that the Antarctic midge is highly resistant to oxidative stress.
Collapse
|
63
|
Lamarque JF, Kinnison DE, Hess PG, Vitt FM. Simulated lower stratospheric trends between 1970 and 2005: Identifying the role of climate and composition changes. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009277] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
64
|
Vyushin DI, Fioletov VE, Shepherd TG. Impact of long-range correlations on trend detection in total ozone. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd008168] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
65
|
Mäder JA, Staehelin J, Brunner D, Stahel WA, Wohltmann I, Peter T. Statistical modeling of total ozone: Selection of appropriate explanatory variables. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007694] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
66
|
Grazing and UV radiation effects on an Antarctic intertidal microalgal assemblage: a long-term field study. Polar Biol 2007. [DOI: 10.1007/s00300-007-0278-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
67
|
Heikkilä A, Tanskanen A, Kärhä P, Hanhi K. Adjusting timing of weathering test to account for seasonal variations in UV exposure. Polym Degrad Stab 2007. [DOI: 10.1016/j.polymdegradstab.2006.12.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
68
|
Terao Y, Logan JA. Consistency of time series and trends of stratospheric ozone as seen by ozonesonde, SAGE II, HALOE, and SBUV(/2). ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007667] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
69
|
McKenzie RL, Aucamp PJ, Bais AF, Björn LO, Ilyas M. Changes in biologically-active ultraviolet radiation reaching the Earth's surface. Photochem Photobiol Sci 2007; 6:218-31. [PMID: 17344959 DOI: 10.1039/b700017k] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Montreal Protocol is working. Concentrations of major ozone-depleting substances in the atmosphere are now decreasing, and the decline in total column amounts seen in the 1980s and 1990s at mid-latitudes has not continued. In polar regions, there is much greater natural variability. Each spring, large ozone holes continue to occur in Antarctica and less severe regions of depleted ozone continue to occur in the Arctic. There is evidence that some of these changes are driven by changes in atmospheric circulation rather than being solely attributable to reductions in ozone-depleting substances, which may indicate a linkage to climate change. Global ozone is still lower than in the 1970s and a return to that state is not expected for several decades. As changes in ozone impinge directly on UV radiation, elevated UV radiation due to reduced ozone is expected to continue over that period. Long-term changes in UV-B due to ozone depletion are difficult to verify through direct measurement, but there is strong evidence that UV-B irradiance increased over the period of ozone depletion. At unpolluted sites in the southern hemisphere, there is some evidence that UV-B irradiance has diminished since the late 1990s. The availability and temporal extent of UV data have improved, and we are now able to evaluate the changes in recent times compared with those estimated since the late 1920s, when ozone measurements first became available. The increases in UV-B irradiance over the latter part of the 20th century have been larger than the natural variability. There is increased evidence that aerosols have a larger effect on surface UV-B radiation than previously thought. At some sites in the Northern Hemisphere, UV-B irradiance may continue to increase because of continuing reductions in aerosol extinctions since the 1990s. Interactions between ozone depletion and climate change are complex and can be mediated through changes in chemistry, radiation, and atmospheric circulation patterns. The changes can be in both directions: ozone changes can affect climate, and climate change can affect ozone. The observational evidence suggests that stratospheric ozone (and therefore UV-B) has responded relatively quickly to changes in ozone-depleting substances, implying that climate interactions have not delayed this process. Model calculations predict that at mid-latitudes a return of ozone to pre-1980 levels is expected by the mid 21st century. However, it may take a decade or two longer in polar regions. Climate change can also affect UV radiation through changes in cloudiness and albedo, without involving ozone and since temperature changes over the 21st century are likely to be about 5 times greater than in the past century. This is likely to have significant effects on future cloud, aerosol and surface reflectivity. Consequently, unless strong mitigation measures are undertaken with respect to climate change, profound effects on the biosphere and on the solar UV radiation received at the Earth's surface can be anticipated. The future remains uncertain. Ozone is expected to increase slowly over the decades ahead, but it is not known whether ozone will return to higher levels, or lower levels, than those present prior to the onset of ozone depletion in the 1970s. There is even greater uncertainty about future UV radiation, since it will be additionally influenced by changes in aerosols and clouds.
Collapse
Affiliation(s)
- R L McKenzie
- National Institute of Water and Atmospheric Research, NIWA Lauder, PB 50061, Omakau, Central Otago, New Zealand
| | | | | | | | | |
Collapse
|
70
|
Zanis P, Maillard E, Staehelin J, Zerefos C, Kosmidis E, Tourpali K, Wohltmann I. On the turnaround of stratospheric ozone trends deduced from the reevaluated Umkehr record of Arosa, Switzerland. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006886] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
71
|
Van Noorden R. Sun helps clean the sky. Nature 2006. [DOI: 10.1038/news060710-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
72
|
Yang ES, Cunnold DM, Salawitch RJ, McCormick MP, Russell J, Zawodny JM, Oltmans S, Newchurch MJ. Attribution of recovery in lower-stratospheric ozone. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006371] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|