| 1. |
- Ristilä, Mikael, et al.
(author)
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The role of the pyridoxine (vitamin B6) biosynthesis enzyme PDX1 in ultraviolet-B radiation responses in plants
- 2011
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In: Plant physiology and biochemistry (Paris). - Amsterdam : Elsevier. - 0981-9428 .- 1873-2690. ; 49:3, s. 284-292
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Journal article (peer-reviewed)abstract
- Ultraviolet-B radiation regulates plant growth and morphology at low and ambient fluence rates but can severely impact on plants at higher doses. Some plant UV-B responses are related to the formation of reactive oxygen species (ROS) and pyridoxine (vitamin B6) has been reported to be a quencher of ROS. UV-B irradiation of Arabidopsis Col-0 plants resulted in increased levels of PDX1 protein, compared with UV-A-exposed plants. This was shown by immunoblot analysis using specific polyclonal antibodies raised against the recombinant PDX1.3 protein and confirmed by mass spectrometry analysis of immunoprecipitated PDX1. The protein was located mainly in the cytosol but also to a small extent in the membrane fraction of plant leaves. Immunohistochemical analysis performed in pea revealed that PDX1 is present in UV-B-exposed leaf mesophyll and palisade parenchyma but not in epidermal cells. Pyridoxine production increased in Col-0 plants exposed to 3 days of UV-B, whereas in an Arabidopsis pdx1.3 mutant UV-B did not induce pyridoxine biosynthesis. In gene expression studies performed after UV-B exposure, the pdx1.3 mutant showed elevated transcript levels for the LHCB1*3 gene (encoding a chlorophyll a/b-binding protein of the photosystem II light-harvesting antenna complex) and the pathogenesis-related protein 5 (PR-5) gene, compared with wild type.
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| 2. |
- Scherbak, Nikolai, et al.
(author)
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The pea SAD short-chain dehydrogenase/reductase : quinone reduction, tissue distribution, and heterologous expression
- 2011
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In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 155:4, s. 1839-1850
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Journal article (peer-reviewed)abstract
- The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression. The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring-membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein demonstrated that different tissues and cell types contain small amounts of SAD protein that was predominantly located within epidermal or subepidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. Ultraviolet-B irradiation led to increased staining in epidermal and subepidermal cells of leaves and stems. The different localization patterns of SAD suggest functions both in development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis (Arabidopsis thaliana), which confirmed that the inducibility of its expression is regulated at the transcriptional level.
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| 3. |
- Andersson, Sören, 1957-, et al.
(author)
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Chimeric MOMP antigen
- 2014
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Patent (pop. science, debate, etc.)abstract
- The present invention regards polypeptides capable of eliciting an immunological response that is protective against Chlamydia trachomatis. The polypeptide comprises a first amino acid sequence which has at least 90% homology with the amino acid sequence according to SEQ ID NO: 1 and a second amino acid sequence which has at least 90% homology with the amino acid sequence according to SEQ ID NO: 2. Furthermore, production of these polypeptides and pharmaceutical compositions comprising them are also provided.
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| 4. |
- Comont, David, et al.
(author)
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Exploring latitudinal variation in UV radiation and climate : impacts on a model grass system
- 2011
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In: Abstracts of the 1st Annual Meeting of COST Action FA0906 UV4growth. - Szeged : Biological Research Center of the Hungarian Academy of Sciences. - 9789635086061 ; , s. 14-14
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Conference paper (peer-reviewed)abstract
- Perennial ryegrass (Lolium perenne) seedlings were grown at 14 European locations across a latitudinal gradient spanning 37 to 68°N. Seedlings planted in nutrient enriched vermiculite were grown outdoors over five weeks between the 29th June and the 3rd August 2010. At each location there were three treatments – open, filtered with cellulose acetate (UV transparent) and filtered with Mylar (UV opaque). Plants were regularly watered and outdoor climatic conditions were monitored at nearby meteorological stations. The aim of the experiment was to assess the significance of ambient UV radiation to L.perenne, both at each location and across the gradient in terms of aboveground biomass, tiller number, and the level of UV protective plant pigments. Material was further screened using metabolite fingerprinting (FT-IR spectroscopy) to assess local, regional and latitudinal variation in total plant chemistry. Data presented will explore and interpret the complex variations in growth and chemistry looking at local responses and the latitudinal gradient explored.
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| 5. |
- Comont, David, et al.
(author)
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UV responses of Lolium perenne raised along a latitudinal gradient across Europe : a filtration study
- 2012
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In: Physiologia Plantarum. - : Wiley-Blackwell. - 0031-9317 .- 1399-3054. ; 145, s. 604-618
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Journal article (peer-reviewed)abstract
- Lolium perenne (cv. AberDart) was grown at 14 locations along a latitudinal gradient across Europe (37–68◦N) to study the impact of ultraviolet radiation (UV) and climate on aboveground growth and foliar UV-B absorbing compounds. At each location, plants were grown outdoors for 5 weeks in a replicated UV-B filtration experiment consisting of open, UV-B transparent (cellulose diacetate) and UV-B opaque (polyester) environments. Fourier transform-infrared spectroscopy was used to compare plantmetabolite profiles in relation to treatment and location. UV radiation and climatic parameters were determined for each location from online sources and the data were assessed using a combination of ANOVA and multiple regression analyses. Most of the variation in growth between the locations was attributable to the combination of climatic parameters, with minimum temperature identified as an important growth constraint. However, no single environmental parameter could consistently account for the variability in plant growth. Concentrations of foliar UV-B absorbing compounds showed a positive trend with solar UV across the latitudinal gradient; however, this relationship was not consistent in all treatments. The most striking experimental outcome from this study was the effect of presence or absence of filtration frames onUV-absorbing compounds. Overall, the study demonstrates the value of an European approach in studying the impacts of natural UV across a large latitudinal gradient. We have shown the feasibility of coordinated UV filtration at multiple sites but have also highlighted the need for open controls and careful interpretation of plant responses.
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| 6. |
- Czegeny, G., et al.
(author)
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Hydrogen peroxide contributes to the ultraviolet-B (280-315 nm) induced oxidative stress of plant leaves through multiple pathways
- 2014
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In: Febs Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 588:14, s. 2255-2261
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Journal article (peer-reviewed)abstract
- Solar UV-B (280-315 nm) radiation is a developmental signal in plants but may also cause oxidative stress when combined with other environmental factors. Using computer modeling and in solution experiments we show that UV-B is capable of photosensitizing hydroxyl radical production from hydrogen peroxide. We present evidence that the oxidative effect of UV-B in leaves is at least twofold: (i) it increases cellular hydrogen peroxide concentrations, to a larger extent in pyridoxine antioxidant mutant pdx1.3-1 Arabidopsis and; (ii) is capable of a partial photo-conversion of both 'natural' and 'extra' hydrogen peroxide to hydroxyl radicals. As stress conditions other than UV can increase cellular hydrogen peroxide levels, synergistic deleterious effects of various stresses may be expected already under ambient solar UV-B. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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| 7. |
- Elmabsout, Ali Ateia, et al.
(author)
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Cloning and Functional Studies of a Splice Variant of CYP26B1 Expressed in Vascular Cells
- 2012
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In: Plos One. - San Francisco, USA : Public Library of Science (PLoS). - 1932-6203. ; 7:5
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Journal article (peer-reviewed)abstract
- Background: All-trans retinoic acid (atRA) plays an essential role in the regulation of gene expression, cell growth and differentiation and is also important for normal cardiovascular development but may in turn be involved in cardiovascular diseases, i.e. atherosclerosis and restenosis. The cellular atRA levels are under strict control involving several cytochromes P450 isoforms (CYPs). CYP26 may be the most important regulator of atRA catabolism in vascular cells. The present study describes the molecular cloning, characterization and function of atRA-induced expression of a spliced variant of the CYP26B1 gene. Methodology/Principal Findings: The coding region of the spliced CYP26B1 lacking exon 2 was amplified from cDNA synthesized from atRA-treated human aortic smooth muscle cells and sequenced. Both the spliced variant and full length CYP26B1 was found to be expressed in cultured human endothelial and smooth muscle cells, and in normal and atherosclerotic vessel. atRA induced both variants of CYP26B1 in cultured vascular cells. Furthermore, the levels of spliced mRNA transcript were 4.5 times higher in the atherosclerotic lesion compared to normal arteries and the expression in the lesions was increased 20-fold upon atRA treatment. The spliced CYP26B1 still has the capability to degrade atRA, but at an initial rate one-third that of the corresponding full length enzyme. Transfection of COS-1 and THP-1 cells with the CYP26B1 spliced variant indicated either an increase or a decrease in the catabolism of atRA, probably depending on the expression of other atRA catabolizing enzymes in the cells. Conclusions/Significance: Vascular cells express the spliced variant of CYP26B1 lacking exon 2 and it is also increased in atherosclerotic lesions. The spliced variant displays a slower and reduced degradation of atRA as compared to the full-length enzyme. Further studies are needed, however, to clarify the substrate specificity and role of the CYP26B1 splice variant in health and disease.
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| 8. |
- Elmabsout, Ali, et al.
(author)
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Cloning and functional studies of a splice variant of CYP26B1 : a cellular storage protein for all-trans retinoic acid
- 2010
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In: In Vivo. - 0258-851X .- 1791-7549. ; 24:3, s. 345-346
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Journal article (peer-reviewed)abstract
- BackgroundAll-trans retinoic acid (atRA) plays an essential role in the regulation of gene expression, cell growth and differentiation and is also important for normal cardiovascular development but may in turn be involved in cardiovascular diseases, i.e. atherosclerosis and restenosis. The cellular atRA levels are under strict control involving several cytochromes P450 isoforms (CYPs). CYP26 may be the most important regulator of atRA catabolism in vascular cells. The present study describes the molecular cloning, characterization and function of atRA-induced expression of a spliced variant of the CYP26B1 gene.Methodology/Principal FindingsThe coding region of the spliced CYP26B1 lacking exon 2 was amplified from cDNA synthesized from atRA-treated human aortic smooth muscle cells and sequenced. Both the spliced variant and full length CYP26B1 was found to be expressed in cultured human endothelial and smooth muscle cells, and in normal and atherosclerotic vessel. atRA induced both variants of CYP26B1 in cultured vascular cells. Furthermore, the levels of spliced mRNA transcript were 4.5 times higher in the atherosclerotic lesion compared to normal arteries and the expression in the lesions was increased 20-fold upon atRA treatment. The spliced CYP26B1 still has the capability to degrade atRA, but at an initial rate one-third that of the corresponding full length enzyme. Transfection of COS-1 and THP-1 cells with the CYP26B1 spliced variant indicated either an increase or a decrease in the catabolism of atRA, probably depending on the expression of other atRA catabolizing enzymes in the cells.Conclusions/SignificanceVascular cells express the spliced variant of CYP26B1 lacking exon 2 and it is also increased in atherosclerotic lesions. The spliced variant displays a slower and reduced degradation of atRA as compared to the full-length enzyme. Further studies are needed, however, to clarify the substrate specificity and role of the CYP26B1 splice variant in health and disease.
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| 9. |
- Eriksson, Leif A., et al.
(author)
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Chemistry of vitamin B6 under oxidative stress
- 2012
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In: UV4growth COST-Action FA0906. - Köpenhamn : University of Copenhagen. ; , s. 28-28
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Conference paper (peer-reviewed)abstract
- Vitamin B6, or pyridoxine, is the precursor of the biologically active derivatives pyridoxal-5’-phosphate and pyridoxamine-5’-phosphate (Fig.1), with functional roles in a number of different enzymes. Pyridoxine itself is a cofactor of several enzymes that catalyze decarboxylations, transaminations, and racemations of amino acids. Bacteria, fungi, and plants produce their own vitamin B6, whereas parasitic organisms and higher animals have to acquire vitamin B6 through nutrient intake.Lately, pyridoxine biosynthesis-deficient mutants of fungi and yeast have been shown to be sensitive to reactive oxygen species (ROS) such as singlet oxygen and hydrogen peroxide. This suggests that vitamin B6 and its derivatives are also involved in stress tolerance in living organisms, especially in alleviating oxidative stress. In eukaryotes, stress resistance has been implied to involve pyridoxine-dependent singlet oxygen quenching, whereby the pyridoxine itself would react with and quench the singlet oxygen. The oxidative stress-protective effect of pyridoxine has also been described both in red blood cells and in lens cells in animals. Pyridoxine itself was found to be the most effective of the vitamin B6 species, twice as effective as pyridoxal-5’-phosphate, and as effective as vitamin E. Knowledge about this novel mechanism of reaction between pyridoxine or its derivatives (cf. Figure 1) and singlet oxygen and other ROS is however very limited. However, since both the aldehyde (pyridoxal) and the amino (pyridoxamine) derivatives only to a small extent influence the rate of reaction, these moieties are probably not involved. Also, since the heteroaromatic absorbance peak at 323 nm disappears during the reaction, at least one of the targets for singlet oxygen is most likely the core of the aromatic ring, leading to ring opening.In order to shed more light on the possible role of pyridoxine in stress tolerance / protection we herein report on computational studies of possible reaction mechanisms between pyridoxine and different ROS (singlet oxygen, superoxide and hydrogen peroxide) by means of density functional theory (DFT) based methods. It is concluded that the compound has an extremely high quenching power towards hydroxyl radicals. We furthermore explore the explicit UV-induced photolysis pathways of the compound, as well as enzymatic degradation (ring-opening) by bacterial flavoprotein monooxygenases.
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| 10. |
- Hadad, Ronza, et al.
(author)
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Optimization of infection in murine model with Chlamydia trachomatis for vaccine studies
- 2013
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In: Chlamydia Basic Research Society.
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Conference paper (peer-reviewed)abstract
- Background and Significance: Vaccine studies for Chlamydia trachomatis (Ct) have been hampered by the lack of an ideal murine model. Ct is not ideal for infection and subsequent pathology as it is a human pathogen and C. muridarum (Cm) may not be suitable due to vaccine specificity for Ct. There is currently no standardization of chlamydial infections in murine models concerning mouse strain, infecting agent and dose. Objectives: To investigate the Ct infection in mice, using different suppliers of mice, doses and the infective agents of Ct serovars D, E and Cm. Methods: C57BL/6 mice (Taconic; Harlan; in-house breeding mice) were inoculated intravaginally with 103-105 chlamydia elementary bodies (EB). Vaginal samples were collected at 7-8 days intervals and analyzed using MicroTrak II Chlamydia EIA kit. Results: Taconic mice inoculated with Ct D with 105 EB showed the strongest infection with 30% of mice infected at day 21 (d21) as seen in figure 1. The number of infected mice and detected antigen (not shown) decreased rapidly after the first time-point (d8). In figure 2 infective agents were analyzed. Ct E did not infect any mice despite using a tenfold increased dose. Cm infection was detectable in 80% of the mice for up to d21. Conclusions: Ct D infected the mice for a period of 2-3 weeks. There was only a small difference between the suppliers in favor for Harlan mice. Ct D 105 EB was the infectious dose with the highest number of infected mice over time, however the appropriateness of that high bacterial load must be considered. Ct E did not infect these mice and Cm, a mouse pneumonitis strain, infected all mice and had the longest duration of infection. However, for vaccine studies, Cm may not be suitable due to lack of cross reactivity and Ct may still be used however vaginal sampling must be more frequent early on to show significant differences in bacterial shedding between immunized and non-immunized mice.
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