| 1. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interaction with climate change: Progress report 2007
- 2008
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 7:1, s. 15-27
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Forskningsöversikt (refereegranskat)abstract
- This year theMontreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the ‘Montreal Protocol on Substances that Deplete the Ozone Layer’. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.
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| 2. |
- Björn, Lars Olof, et al.
(författare)
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Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2004
- 2005
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 4:2, s. 177-184
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Forskningsöversikt (refereegranskat)abstract
- The measures needed for the protection of the layer are decided regularly by the Parties to the Montreal Protocol, now consisting of 188 countries. The Parties are advised on knowledge relevant to this task by three panels of experts: the Scientific, Environmental Effects, and Technology and Economic Assessment Panels. These panels produce an assessment every four years. The Environmental Effects Assessments are also published in the scientific literature; the latest report was published as a series of papers in Photochemical & Photobiolog-ical Sciences, 2003, 2, 1–72. In the intermediate years, the panels keep the Parties informed on new developments. The following Progress Report is the 2004 update by the Environmental Effects Assessment Panel and follows that for 2003 (Photochemical & Photobiological Sciences, 2004, 3, 1–5). Since the first assessments in 1989, the complexity of the linkages between ozone depletion (Fig. 1), UV-B radiation and climate change has become more apparent. This makes it even clearer than before that we are dealing with long-term ozone developments, which can be complicated by large year to year variability. Originally published by the United Nations Environment Programme (UNEP) as Environmental Effects of Ozone Depletion and its Interactions with Climate Change: Progress Report 2004.
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| 3. |
- Björn, Lars Olof, et al.
(författare)
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Photosensitivity in sponge due to cytochrome c oxidase?
- 2009
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 8, s. 755-757
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Tidskriftsartikel (refereegranskat)abstract
- An action spectrum for photosensitivity in sponge larvae published by Leys et al. [J. Comp. Physiol., A, 2002, 188, 199–202] was interpreted by the authors as being due to a combination of light absorption by flavin or carotenoid in the blue region, and another pigment such as pterin in the long-wavelength region. Here we show here that their action spectrum closely matches the absorption spectrum of reduced cytochrome c oxidase that is present in sponges, and compare with other photoreactions which are thought to be due to this chromoprotein.
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| 4. |
- Campbell, Eleanor E B, 1960, et al.
(författare)
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Ionisation of Fullerenes and Fullerene Clusters using Ultrashort Laser Pulses
- 2006
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Ingår i: Photochem. Photobiol. Sci.. - : Springer Science and Business Media LLC. - 1474-905X. ; 5, s. 1183-1189
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Tidskriftsartikel (refereegranskat)abstract
- We give a brief review of the literature concerning the ultra-short pulse ionisation of fullerenes in the gas phase. Emphasis is placed on the excitation time dependence of different ionisation regimes as manifested by photoelectron spectroscopy. The ionisation rates are modelled for the intermediate situation where the excitation energy is equilibrated between electronic degrees of freedom but not yet coupled to vibrational degrees of freedom. The model is shown to describe many aspects of the experiments. New results are presented on the intra-cluster molecular fusion of fullerene molecules when van der Waals bound clusters of fullerenes are exposed to ultra-short laser pulses. Pump–probe measurements give a decay time constant for the intra-cluster fusion reaction of 520 ± 55 fs. A comparison with monomer ionisation results suggests that the time window for the fusion reaction is influenced by the coupling of the electronic excitation energy to vibrational degrees of freedom of the molecules in the cluster.
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| 5. |
- Chmyrov, Andriy, 1979-, et al.
(författare)
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Characterization of new fluorescent labels for ultra-high resolution microscopy
- 2008
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-905X .- 1474-9092. ; 7:11, s. 1378-1385
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Tidskriftsartikel (refereegranskat)abstract
- Photo-induced switching of dyes into dark, long-lived states, such as a triplet state, has recently gained increasing interest, as a means to achieve ultra-high optical resolution. Additionally, these long lived states are often highly environment-sensitive and their photodynamics can thus offer additional independent fluorescence-based information. However, although providing a useful mechanism for photo-induced switching, the triplet state often appears as a precursor state for photobleaching, which potentially can limit its usefulness. In this work, a set of rhodamine and pyronin dyes, modified by substitution of heavy atoms and nitrogen within or close to the central xanthene unit of the dyes, were investigated with respect to their triplet state dynamics and photostabilities, under conditions relevant for ultra-high resolution microscopy. Out of the dyes investigated, in particular the rhodamine and pyronin dyes with a sulfur atom replacing the central oxygen atom in the xanthene unit were found to meet the requirements for ultra-high resolution microscopy, combining a prominent triplet state yield with reasonable photostability.
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| 6. |
- García-Lorenzo, Maribel, et al.
(författare)
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Degradation of the main Photosystem II light-harvesting complex
- 2005
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-905X .- 1474-9092. ; 4, s. 1065-1071
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Tidskriftsartikel (refereegranskat)abstract
- Many factors trigger the degradation of proteins, including changes in environmental conditions, genetic mutations, and limitations in the availability of cofactors. Despite the importance for viability, still very little is known about protein degradation and its regulation. The degradation of the most abundant membrane protein on Earth, the light-harvesting complex of Photosystem II (LHC II), is highly regulated under different environmental conditions, e.g. light stress, to prevent photochemical damage of the reaction center. However, despite major effort to identify the protease/proteases involved in the degradation of the apoproteins of LHC II the molecular details of this important process remain obscure. LHC II belongs to the family of chlorophyll a/b binding proteins (CAB proteins) and is located in the thylakoid membrane of the plant chloroplast. The results of biochemical experiments to isolate and characterize the protease degrading LHC II are summarized here and compared to our own recent finding indicating that a metalloprotease of the FtsH family is involved in this process.
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| 7. |
- Guedes, Rita Cardoso, et al.
(författare)
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Photophysics, photochemistry, and reactivity : Molecular aspects of perylenequinone reactions
- 2007
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Ingår i: Photochemical and Photobiological Sciences. - Cambridge : Royal Society of Chemistry. - 1474-905X .- 1474-9092. ; 6:10, s. 1089-1096
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Tidskriftsartikel (refereegranskat)abstract
- Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were used to elucidate the photochemistry and photophysics of eight different perylenequinones (PQ). The objective of this work has been to quantitatively investigate the photodynamic therapeutic potential of this family of compounds and give an overview of their photoreactivity. The effects of solvation were evaluated through single-point calculations using the integral equation formalism of the polarised continuum model. It is concluded that the eight studied perylenequinones can generate singlet oxygen (in aqueous solution) and superoxide radical anions, and that the autoionisation of two nearby PQ molecules is possible.
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| 8. |
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| 9. |
- Hansson, Lars-Anders, et al.
(författare)
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Effects of ultraviolet radiation on pigmentation, photoenzymatic repair, behavior, and community ecology of zooplankton
- 2009
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-905X .- 1474-9092. ; 8:9, s. 1266-1275
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Tidskriftsartikel (refereegranskat)abstract
- In this report, we provide a perspective on how zooplankton are able to respond to present and future levels of ultraviolet (UV) radiation, a threat that has been present throughout evolutionary time. To cope with this threat, zooplankton have evolved several adaptations including behavioral responses, repair systems, and accumulation of photoprotective compounds. Common photoprotective compounds include melanins and carotenoids, which are true pigments, but also mycosporine-like amino acids (MAAs) and several other substances, and different taxa use different blends of these compounds. It is not only the level of UV radiation, however, that determines the amount of photoprotective compounds incorporated by the zooplankton, but also other environmental factors, such as predation and supply rate of the compounds. Furthermore, compared to taxa that are less pigmented, those taxa with ample pigmentation are generally less likely to exhibit diel migration. The photoenzymatic repair of UV damages seems to be more efficient at intermediate temperature than at low and high temperatures, suggesting that it is less useful at high and low latitudes, where UV radiation is often extremely high. While predicted future increases in UV radiation are expected to substantially affect many processes, recent studies show that most zooplankton taxa are well adapted to cope with such increases, either by UV avoidance behavior or by incorporation of photoprotective compounds. Hence, we conclude that future increase in UV radiation will have only moderate direct effects on zooplankton biomass and community dynamics.
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| 10. |
- Jiang, Lei, et al.
(författare)
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Arabidopsis RADICAL-INDUCED CELL DEATH1 is involved in UV-B signaling.
- 2009
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 8, s. 838-846
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Tidskriftsartikel (refereegranskat)abstract
- The Arabidopsis radical-induced cell death1 (rcd1) mutant is sensitive to ozone fumigation and apoplastic superoxide, but tolerant to methyl viologen. In the present article, we report that the rcd1 mutant is also tolerant to supplementary UV-B radiation. The rcd1-1 mutant exhibits less accumulation of TT dimers, increased hypocotyl growth inhibition and higher accumulation of flavonoids under supplemental UV-B radiation. Moreover, the expression of HY5 (ELONGATED HYPOCOTYL5) is increased in the mutant after UV-B treatment. Gene expression downstream of UV-B signaling reveals that COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC1)-regulated genes have an elevated expression in rcd1-1 mutant under UV-B radiation, while expression of UVR8 (UV RESISTANCE LOCUS 8)-regulated and HY5-independent genes are not changed. Interestingly, the expression of RCD1 genes is not significantly changed by UV-B radiation. Previous study has shown that STO protein is interacting with RCD1 in vitro. Here, we found the mRNA level of STO (SALT TOLERANCE) is greatly increased in rcd1-1 mutant after UV-B radiation. However, UV-B-induced HY5 and CHS expression is partially inhibited in sto mutant. Based on the above results, it is deduced that the RCD1, working together with STO, is involved in Arabidopsis UV-B signaling.
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