83 results on '"Wannijn, J."'
Search Results
2. Predicting the environmental risks of radioactive discharges from Belgian nuclear power plants
- Author
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Vandenhove, H., Sweeck, L., Vives i Batlle, J., Wannijn, J., Van Hees, M., Camps, J., Olyslaegers, G., Miliche, C., and Lance, B.
- Published
- 2013
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3. Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass
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Duquène, L., Vandenhove, H., Tack, F., Van Hees, M., and Wannijn, J.
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- 2010
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4. Interception of radionuclides by planophile crops: A simple semi-empirical modelling approach in case of nuclear accident fallout
- Author
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Cristina, A., primary, Samson, R., additional, Horemans, N., additional, Van Hees, M., additional, Wannijn, J., additional, Bruggeman, M., additional, and Sweeck, L., additional
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- 2020
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5. Plant-induced changes in soil chemistry do not explain differences in uranium transfer
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Duquène, L., Vandenhove, H., Tack, F., Van der Avoort, E., Van Hees, M., and Wannijn, J.
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- 2006
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6. MiRNA398b and miRNA398c are involved in the regulation of the SOD response in uranium-exposed Arabidopsis thaliana roots
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Saenen, E., primary, Horemans, N., additional, Vanhoudt, N., additional, Vandenhove, H., additional, Biermans, G., additional, Van Hees, M., additional, Wannijn, J., additional, Vangronsveld, J., additional, and Cuypers, A., additional
- Published
- 2015
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7. Assessment of the radiological impact and associated risk to non-human biota from routine liquid discharges of the Belgian nuclear power plants
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Vandenhove, H., primary, Sweeck, L., additional, Wannijn, J., additional, Van Hees, M., additional, and Lance, B., additional
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- 2012
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8. On the nature and timing of oxygen radical production following exposure ofArabidopsis thalianaleaves to uranium, cadmium or a combination of both stressors
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Horemans, N., primary, Vanhoudt, N., additional, Janssens, M., additional, Van Chaze, B., additional, Wannijn, J., additional, Van Hees, M., additional, and Vandenhove, H., additional
- Published
- 2011
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9. Study of biological effects and oxidative stress related responses in gamma irradiatedArabidopsis thalianaplants
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Vanhoudt, N., primary, Cuypers, A., additional, Vangronsveld, J., additional, Horemans, N., additional, Wannijn, J., additional, Van Hees, M., additional, and Vandenhove, H., additional
- Published
- 2011
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10. Enhanced phytoextraction of uranium and selected heavy metals by Indian mustard and ryegrass using biodegradable soil amendments
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Duquène, L., primary, Vandenhove, H., additional, Tack, F., additional, Meers, E., additional, Baeten, J., additional, and Wannijn, J., additional
- Published
- 2009
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11. Induction of oxidative stress related responses inArabidopsis thalianafollowing uranium exposure
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Vanhoudt, N., primary, Vandenhove, H., additional, Opdenakker, K., additional, Remans, T., additional, Smeets, K., additional, Martinez Bello, D., additional, Van Hees, M., additional, Wannijn, J., additional, Vangronsveld, J., additional, and Cuypers, A., additional
- Published
- 2009
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12. Tolerance of hairy roots of carrots to U chronic exposure in a standardized in vitro device
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STRACZEK, A, primary, WANNIJN, J, additional, VANHEES, M, additional, THIJS, H, additional, and THIRY, Y, additional
- Published
- 2009
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13. Testing the potential of enhanced phytoextraction to clean up NORM and heavy metal contaminated soils
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Vandenhove, H., primary, Duquène, L., additional, Tack, F., additional, Baeten, J., additional, and Wannijn, J., additional
- Published
- 2009
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14. Method of diffusive gradients in thin films (DGT) compared with other soil testing methods to predict phytoavailability of uranium and selected heavy metals from multipolluted soils
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Vandenhove, H., primary, Wannijn, J., additional, Duquène, L., additional, and Hees, M. V., additional
- Published
- 2009
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15. Effect of low-dose chronic gamma exposure on growth and oxidative stress related responses inArabidopsis thaliana
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Vandenhove, H., primary, Vanhoudt, N., additional, Wannijn, J., additional, Van Hees, M., additional, and Cuypers, A., additional
- Published
- 2009
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16. Effect of biodegradable amendments on uranium solubility in contaminated soils
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Duquène, L., primary, Tack, F., additional, Meers, E., additional, Baeten, J., additional, Wannijn, J., additional, and Vandenhove, H., additional
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- 2008
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17. Method of diffusive gradients in thin films (DGT) compared with other soil testing methods to predict uranium phytoavailability
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Vandenhove, H., primary, Antunes, K., additional, Wannijn, J., additional, Duquène, L., additional, and Van Hees, M., additional
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- 2007
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18. Can we predict uranium bioavailability based on soil parameters? Part 2: Soil solution uranium concentration is not a good bioavailability index
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Vandenhove, H., primary, Van Hees, M., additional, Wannijn, J., additional, Wouters, K., additional, and Wang, L., additional
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- 2007
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19. Can we predict uranium bioavailability based on soil parameters? Part 1: Effect of soil parameters on soil solution uranium concentration
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Vandenhove, H., primary, Van Hees, M., additional, Wouters, K., additional, and Wannijn, J., additional
- Published
- 2007
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20. Oxidative stress reactions induced in beans (Phaseolus vulgaris) following exposure to uranium
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Vandenhove, H., primary, Cuypers, A., additional, Van Hees, M., additional, Koppen, G., additional, and Wannijn, J., additional
- Published
- 2006
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21. Study of biological effects and oxidative stress related responses in gamma irradiated Arabidopsis thalianaplants
- Author
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Vanhoudt, N., Cuypers, A., Vangronsveld, J., Horemans, N., Wannijn, J., Van Hees, M., and Vandenhove, H.
- Abstract
This study aimed at investigating biological effects in Arabidopsis thalianaleaves and roots irradiated for 72 h with 3.5 Gy or 30 Gy of gamma radiation, and to unravel oxidative stress related responses to achieve a better understanding of the importance of the cellular redox balance as a modulator in gamma radiation stress. A. thalianaperforms like a rather radioresistant plant species as no alterations on growth and only minor alterations in the nutrient profile were observed. Gamma irradiation did not seem to induce an NADPH mediated oxidative burst and lipid peroxidation appeared to be directly induced by ionizing radiation rather than mediated through LOX activity. As ionizing radiation can cause indirect damage via water radiolysis, H2O2is hypothesized to be an important reactive oxygen species under radiation stress. Although most H2O2-scavenging enzymes remained unchanged, important alterations were observed for CAT1, CAT2and CAT3expression.
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- 2011
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22. On the nature and timing of oxygen radical production following exposure of Arabidopsis thalianaleaves to uranium, cadmium or a combination of both stressors
- Author
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Horemans, N., Vanhoudt, N., Janssens, M., Van Chaze, B., Wannijn, J., Van Hees, M., and Vandenhove, H.
- Abstract
The toxicity and oxidative stress responses of 19-day old Arabidopsisseedlings induced by U (66 μM) and Cd (20 μM) alone or in a binary mixture set-up (equitoxic mixture) are studied in function of time. After 48h a significant decrease in root and shoot growth and a simultaneous increase in anthocyanin production was evident in all treated plants.
- Published
- 2011
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23. Effect of low-dose chronic gamma exposure on growth and oxidative stress related responses in Arabidopsis thaliana
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Vandenhove, H., Vanhoudt, N., Wannijn, J., Van Hees, M., and Cuypers, A.
- Abstract
The biological responses induced by low-dose chronic gamma exposure of hydroponically grown Arabidopsis thaliana, irradiated during a full life cycle (seed to seed) were investigated. Applied dose rates were 2300, 375 and 85 µGray h-1. Plants (roots and shoots) were harvested after 24 day (inflorescence emergence), at 34 days (∼50% of flowers open) and at 54 days (silice ripening). Gamma exposure significantly reduced root weight compared to the control but no clear effect of dose rate level on root dry weight was observed. Leaf weight was significantly reduced at the highest irradiation level, only after 54 days exposure. ED-10 was estimated at 10 µGy h-1. Seed germination was not affected by gamma irradiation. For several of the stress enzymes studied enzyme capacity was generally stimulated at the low and intermediate gamma irradiation level compared to the control and highest irradiation level. No pattern was observed in concentration or reduction state of the non-enzymatic antioxidants, ascorbate and glutathione. Lipid peroxidation products in leaves were present highest at full flowering and decreased with exposure level at this growth stage. At the other two growth stages, lipid peroxidation products were unaffected by gamma treatment.
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- 2009
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24. Induction of oxidative stress related responses in Arabidopsis thalianafollowing uranium exposure
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Vanhoudt, N., Vandenhove, H., Opdenakker, K., Remans, T., Smeets, K., Martinez Bello, D., Van Hees, M., Wannijn, J., Vangronsveld, J., and Cuypers, A.
- Abstract
The reactive oxygen species (ROS)-signaling pathway is very important in heavy metal toxicity. Induction of the antioxidative defense mechanism, comprising ROS-scavenging enzymes and metabolites, in plants after environmental uranium contamination has been insufficiently studied in the past. This study aimed to analyze oxidative stress related responses in Arabidopsis thalianaafter uranium exposure. Seventeen-day-old seedlings were exposed to 0, 0.1, 1, 10 and 100 μM uranium for 3 days. After exposure to 100 μM uranium, a decrease in fresh weight for leaves and roots was observed, leaves colored anthocyanous and roots were stunted and yellow. To reveal the importance of oxidative stress in uranium toxicity, alterations in ROS-scavenging enzymes were studied at protein and transcriptional level. Superoxide dismutase (SOD) capacities increased in leaves and roots after exposure to 100 μM uranium but no differences were observed for catalase (CAT) capacities. Transcript levels of different SODs located at various cellular compartments were affected depending on the place of action. Gene expression of CAT in leaves and roots was also affected after uranium exposure. Results indicate that oxidative stress plays an important role in uranium toxicity but suggest that plant responses differ for leaves and roots.
- Published
- 2009
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25. Induction of oxidative stress related responses inArabidopsis thalianafollowing uranium exposure
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M. Van Hees, Jaco Vangronsveld, D. Martinez Bello, Hildegarde Vandenhove, Nathalie Vanhoudt, Tony Remans, Jean Wannijn, Kelly Opdenakker, Ann Cuypers, Karen Smeets, VANHOUDT, Nathalie, VANDENHOVE, Hildegarde, OPDENAKKER, Kelly, REMANS, Tony, SMEETS, Karen, Martinez Bello, Daniel, VAN HEES, M., WANNIJN, J., VANGRONSVELD, Jaco, and CUYPERS, Ann
- Subjects
inorganic chemicals ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Metal toxicity ,medicine.disease_cause ,complex mixtures ,Toxicology ,Superoxide dismutase ,medicine ,Arabidopsis thaliana ,Safety, Risk, Reliability and Quality ,Waste Management and Disposal ,chemistry.chemical_classification ,Reactive oxygen species ,biology ,Renewable Energy, Sustainability and the Environment ,technology, industry, and agriculture ,Public Health, Environmental and Occupational Health ,Uranium ,biology.organism_classification ,Nuclear Energy and Engineering ,Biochemistry ,chemistry ,Catalase ,Toxicity ,biology.protein ,Oxidative stress - Abstract
The reactive oxygen species (ROS)-signaling pathway is very important in heavy metal toxicity. Induction of the antioxidative defense mechanism, comprising ROS-scavenging enzymes and metabolites, in plants after environmental uranium contamination has been insufficiently studied in the past. This study aimed to analyze oxidative stress related responses in Arabidopsis thaliana after uranium exposure. Seventeen-day-old seedlings were exposed to 0, 0.1, 1, 10 and 100 μM uranium for 3 days. After exposure to 100 μM uranium, a decrease in fresh weight for leaves and roots was observed, leaves colored anthocyanous and roots were stunted and yellow. To reveal the importance of oxidative stress in uranium toxicity, alterations in ROS-scavenging enzymes were studied at protein and transcriptional level. Superoxide dismutase (SOD) capacities increased in leaves and roots after exposure to 100 μM uranium but no differences were observed for catalase (CAT) capacities. Transcript levels of different SODs located at various cellular compartments were affected depending on the place of action. Gene expression of CAT in leaves and roots was also affected after uranium exposure. Results indicate that oxidative stress plays an important role in uranium toxicity but suggest that plant responses differ for leaves and roots.
- Published
- 2009
26. Highly weathered mineral soils have highest transfer risk of radiocaesium contamination after a nuclear accident: A global soil-plant study.
- Author
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Vanheukelom M, Sweeck L, Almahayni T, De Bruyn M, Steegmans P, Fondu L, Van Gompel A, Van Hees M, Wannijn J, and Smolders E
- Subjects
- Radioactive Hazard Release, Lolium, Cesium Radioisotopes analysis, Soil Pollutants, Radioactive analysis, Soil chemistry, Radiation Monitoring
- Abstract
Accidental release of radiocaesium (
137 Cs) from nuclear power plants may result in long-term contamination of environmental and food production systems. Assessment of food chain contamination with137 Cs relies on137 Cs soil-to-plant transfer data and models mainly available for regions affected by the Chornobyl and Fukushima accidents. Similar data and models are lacking for other regions. Such information is needed given the global expansion of nuclear energy. We collected 38 soils worldwide of contrasting parent materials and weathering stages. The soils were spiked with137 Cs and sown with ryegrass in greenhouse conditions. The137 Cs grass-soil concentration ratio varied four orders of magnitude among soils. It was highest in Ferralsols due to the low137 Cs interception potential of kaolinite clay and the low exchangeable potassium in these soils. Our results demonstrate, for the first time, the high plant uptake of137 Cs in tropical soils. The most recent137 Cs transfer model, mainly calibrated to temperate soils dominated by weathered micas, poorly predicts the underlying processes in tropical soils but, due to compensatory effect, still reasonably well predicts137 Cs bioavailability across all soils (R2 = 0.8 on a log-log scale)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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27. The nitric oxide suppressed Arabidopsis mutants- Atnoa1 and Atnia1nia2noa1-2 produce nitric oxide in MS growth medium and on uranium exposure.
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Tewari RK, Horemans N, Nauts R, Wannijn J, Van Hees M, and Vandenhove H
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- Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis Proteins drug effects, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Gene Expression Regulation, Plant drug effects, Gene Expression Regulation, Plant genetics, Mutation genetics, Uranium pharmacology, Arabidopsis metabolism, Nitric Oxide pharmacology
- Abstract
The mutants Atnoa1 and Atnia1nia2noa1-2 having a defective chloroplast developmental process, showed enhanced chlorophyll levels when they were grown on Murashige and Skoog (MS) medium and on exposure with uranium (U) on Hoagland medium. Thus we hypothesized that these mutants probably produced NO in MS medium and on exposure with U. Wild-type Col-0, Atnoa1, Atnia1nia2noa1-2 plants were cultured on modified Hoagland and 1/10 MS media and NO generation in the roots of these mutants was monitored using NO selective fluorescent dyes, DAF-2DA and Fl2E. Both Atnoa1 and Atnia1nia2noa1-2 triple mutants produced NO as observed by increases in DAF-2T and Fl2E fluorescence when these mutants were grown on MS medium but not on Hoagland medium. In presence of NO scavenger, methylene blue (MB, 200 μM), DAF-2T and Fl2E fluorescence was completely abolished. On the other hand treatment of the plants with 25 μM U triggered NO generation. U-treated Atnoa1 and Atnia1nia2noa1-2 plants upregulated genes (POR B, POR D, CHL D) involved in the chlorophyll biosynthesis. From these results it was concluded that Atnoa1 and Atnia1nia2noa1-2 are conditional NO producers and it appears that NO generation in plants substantially depends on growth medium and NIA1, NIA2 or NOA1 does not appear to be really involved in NO generation in MS medium or after U exposure., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)
- Published
- 2019
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28. Exposure to ionizing radiation affects the growth of ectomycorrhizal fungi and induces increased melanin production and increased capacities of reactive oxygen species scavenging enzymes.
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Kothamasi D, Wannijn J, Van Hees M, Nauts R, Van Gompel A, Vanhoudt N, and Vandenhove H
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- Basidiomycota, Cesium Radioisotopes, Ecosystem, Fungi, Mycorrhizae enzymology, Mycorrhizae growth & development, Reactive Oxygen Species metabolism, Melanins metabolism, Mycorrhizae radiation effects, Radiation, Ionizing
- Abstract
Ectomycorrhizal (EM) fungi form symbioses with dominant tree families in boreal, temperate and tropical ecosystems and are important drivers of ecosystem function. EM fungal hyphae extend over a large area making them susceptible to enhanced radiation levels from naturally occurring or anthropogenically originating radioisotopes in the rhizosphere. In this study, the in-vitro effects of ionizing radiation on the growth and biomass of EM fungi Suillus luteus, S. bovinus and Rhizopogon luteolus were investigated. EM fungal cultures were exposed to gamma radiation from a
137 Cs source for 137 h in darkness at 21 °C at dose rates of 404, 108.5 and 54.9 mGy h-1 resulting in total absorbed doses of 55.21, 14.82 and 7.50 Gy respectively. Cultures grown in the dark at 21 °C but not exposed to the137 Cs source served as the control. Our results show that EM fungi vary in their sensitivity to ionizing radiation. EM fungi used in this study produced melanin and reactive oxygen species scavenging enzymes such as catalase and superoxide dismutase as a response to ionizing radiation., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2019
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29. Foliar uptake of radiocaesium from irrigation water by paddy rice (Oryza sativa): an overlooked pathway in contaminated environments.
- Author
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Uematsu S, Vandenhove H, Sweeck L, Hees MV, Wannijn J, and Smolders E
- Subjects
- Kinetics, Plant Roots drug effects, Plant Roots metabolism, Plant Shoots drug effects, Plant Shoots metabolism, Plant Stems drug effects, Plant Stems metabolism, Potassium pharmacology, Solutions, Agricultural Irrigation, Cesium Radioisotopes metabolism, Oryza metabolism, Plant Leaves metabolism, Water Pollution, Radioactive analysis
- Abstract
Flooded (paddy) rice (Oryza sativa) can take up ions from the irrigation water by foliar uptake via the exposed stem base. We hypothesised that the stem base uptake of radiocaesium (RCs) is a pathway for rice grown in RCs-contaminated environments. We developed a bi-compartmental device which discriminates the stem base from root RCs uptake from solutions, thereby using RCs isotopes (
137 Cs and134 Cs) with < 2% solution leak between the compartments. Radiocaesium uptake was linear over time (0-24 h). Radiocaesium uptake to the entire plant, expressed per dry weight of the exposed parts, was sixfold higher for the roots than for the exposed stem base. At equal RCs concentrations in both compartments, the exposed stem base and root uptake contributed almost equally to the total shoot RCs concentrations. Reducing potassium supply to the roots not only increased the root RCs uptake but also increased RCs uptake by the stem base. This study was the first to experimentally demonstrate active and internally regulated RCs uptake by the stem base of rice. Scenario calculations for the Fukushima-affected area predict that RCs in irrigation water could be an important source of RCs in rice as indirectly suggested from field data., (© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.)- Published
- 2017
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30. Arabidopsis plants exposed to gamma radiation in two successive generations show a different oxidative stress response.
- Author
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van de Walle J, Horemans N, Saenen E, Van Hees M, Wannijn J, Nauts R, van Gompel A, Vangronsveld J, Vandenhove H, and Cuypers A
- Subjects
- Catalase metabolism, Glutathione metabolism, Oxidation-Reduction, Peroxidases metabolism, Plant Roots metabolism, Arabidopsis physiology, Arabidopsis radiation effects, Gamma Rays, Oxidative Stress physiology
- Abstract
When terrestrial environments get contaminated with long-lived gamma emitting radionuclides, plants that grow in these contaminated areas are exposed to gamma radiation during consecutive generations. Therefore it is important to evaluate the gamma induced stress response in plants in and between generations. The objective of this research is to reveal differences at the level of the antioxidative stress response between generations with a different radiation history. An experiment was conducted in which 7-days old Arabidopsis thaliana plants were exposed for 14 days to four different gamma dose rates: 22 mGy/h, 38 mGy/h, 86 mGy/h and 457 mGy/h. Two different plant groups were used: plants that were not exposed to gamma radiation before (P0) and plants that received the aforementioned gamma treatment during their previous generation (S1). Growth, the concentration of the antioxidants ascorbate and glutathione, a number of antioxidative enzyme activities and their gene transcript levels were analysed. A dose-rate dependent induction was seen for catalase (CAT) and guaiacol peroxidase (GPX) in the roots and for syringaldazine peroxidase (SPX) in the shoots. Differences between the two generations were observed for CAT and GPX in the roots, where a significantly higher activity of these reactive oxygen species (ROS) detoxifying enzymes was observed in the S1 generation. For SPX in the shoots, a dose dependent upregulation was observed in the P0 generation. However, high SPX activities were present for all doses in the S1 generation. These differences in enzyme activity between generations for SPX and GPX and the involvement of these enzymes in cell wall biosynthesis, suggest an important role for cell wall strengthening in the response to gamma irradiation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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31. Rhizophagus irregularis MUCL 41833 can colonize and improve P uptake of Plantago lanceolata after exposure to ionizing gamma radiation in root organ culture.
- Author
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Kothamasi D, Wannijn J, van Hees M, Nauts R, van Gompel A, Vanhoudt N, Cranenbrouck S, Declerck S, and Vandenhove H
- Subjects
- Beta Particles, Glomeromycota growth & development, Glomeromycota metabolism, Mycorrhizae radiation effects, Phosphorus analysis, Plant Roots growth & development, Plant Roots metabolism, Plant Roots microbiology, Plantago microbiology, Radiation, Ionizing, Seedlings microbiology, Soil, Spores, Fungal metabolism, Spores, Fungal radiation effects, Symbiosis, Gamma Rays, Glomeromycota radiation effects, Phosphorus metabolism, Plantago metabolism
- Abstract
Long-lived radionuclides such as (90)Sr and (137)Cs can be naturally or accidentally deposited in the upper soil layers where they emit β/γ radiation. Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can accumulate and transfer radionuclides from soil to plant, but there have been no studies on the direct impact of ionizing radiation on AMF. In this study, root organ cultures of the AMF Rhizophagus irregularis MUCL 41833 were exposed to 15.37, 30.35, and 113.03 Gy gamma radiation from a (137)Cs source. Exposed spores were subsequently inoculated to Plantago lanceolata seedlings in pots, and root colonization and P uptake evaluated. P. lanceolata seedlings inoculated with non-irradiated AMF spores or with spores irradiated with up to 30.35 Gy gamma radiation had similar levels of root colonization. Spores irradiated with 113.03 Gy gamma radiation failed to colonize P. lanceolata roots. P content of plants inoculated with non-irradiated spores or of plants inoculated with spores irradiated with up to 30.35 Gy gamma radiation was higher than in non-mycorrhizal plants or plants inoculated with spores irradiated with 113.03 Gy gamma radiation. These results demonstrate that spores of R. irregularis MUCL 41833 are tolerant to chronic ionizing radiation at high doses.
- Published
- 2016
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32. Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.
- Author
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Uematsu S, Vandenhove H, Sweeck L, Van Hees M, Wannijn J, and Smolders E
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- Environmental Monitoring, Europe, Japan, Models, Theoretical, Soil Pollutants, Radioactive analysis, Soil Pollutants, Radioactive metabolism, Cesium Radioisotopes analysis, Cesium Radioisotopes metabolism, Plants metabolism, Potassium analysis, Radiation Monitoring, Soil chemistry
- Abstract
Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils. An average ammonium concentration was used throughout in the prediction. The measured RIP ranged 14-fold and measured mK varied 37-fold among the soils. The measured RIP was lower than the RIP predicted from the soil clay content likely due to the lower content of weathered micas in the clay fraction of Japanese soils. Also the measured mK was lower than that predicted. As a result, the predicted TFs relying on the measured RIP and mK were, on average, about 22-fold larger than the TFs predicted using the European calibrated models. The geometric mean of the measured TFs for grass in the affected area (N = 82) was in the middle of both. The TFs were poorly related to soil classification classes, likely because soil fertility (mK) was obscuring the effects of the soil classification related to the soil mineralogy (RIP). This study suggests that, on average, Japanese soils are more vulnerable than European soils at equal soil clay and exchangeable K content. The affected regions will be targeted for refined model validation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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33. Oxidative stress responses induced by uranium exposure at low pH in leaves of Arabidopsis thaliana plants.
- Author
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Saenen E, Horemans N, Vanhoudt N, Vandenhove H, Biermans G, van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Antioxidants metabolism, Arabidopsis metabolism, Dose-Response Relationship, Radiation, Gene Expression Regulation, Plant radiation effects, Hydrogen-Ion Concentration, Plant Leaves metabolism, Plant Leaves radiation effects, Arabidopsis radiation effects, Oxidative Stress radiation effects, Uranium toxicity
- Abstract
Anthropogenic activities have led to a widespread uranium (U) contamination in many countries. The toxic effects of U at the cellular level have mainly been investigated at a pH around 5.5, the optimal pH for hydroponically grown plants. However, since the speciation of U, and hence its toxicity, is strongly dependent on environmental factors such as the pH, it is important to investigate the effects of U at different environmentally relevant pH levels. Although U is poorly translocated from the roots to the shoots, resulting in a low U concentration in the leaves, it has been demonstrated that toxic effects in the leaves were already visible after 1 day exposure at pH 5.5, although only when exposed to relatively high U concentrations (100 μM). Therefore, the present study aimed to analyse the effects of different U concentrations (ranging from 0 to 100 μM) at pH 4.5 in leaves of Arabidopsis thaliana plants. Results indicate that U induces early senescence in A. thaliana leaves as was suggested by a decreased expression of CAT2 accompanied by an induction of CAT3 expression, a decreased CAT capacity and an increased lipid peroxidation. In addition, miRNA398b/c is involved in the regulation of the SOD response in the leaves. As such, an increased MIR398b/c expression was observed leading to a decreased transcript level of CSD1/2. Finally, the biosynthesis of ascorbate was induced after U exposure. This can point towards an important role for this metabolite in the scavenging of reactive oxygen species under U stress., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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34. Biological effects of α-radiation exposure by (241)Am in Arabidopsis thaliana seedlings are determined both by dose rate and (241)Am distribution.
- Author
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Biermans G, Horemans N, Vanhoudt N, Vandenhove H, Saenen E, Van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Antioxidants metabolism, Arabidopsis growth & development, Arabidopsis metabolism, DNA Repair radiation effects, Dose-Response Relationship, Radiation, Oxidative Stress radiation effects, Photosynthesis radiation effects, Plant Roots metabolism, Plant Roots radiation effects, Plant Shoots metabolism, Plant Shoots radiation effects, Alpha Particles adverse effects, Americium toxicity, Antioxidants radiation effects, Arabidopsis radiation effects, DNA Damage, Transcription, Genetic radiation effects
- Abstract
Human activity has led to an increasing amount of radionuclides in the environment and subsequently to an increased risk of exposure of the biosphere to ionising radiation. Due to their high linear energy transfer, α-emitters form a threat to biota when absorbed or integrated in living tissue. Among these, (241)Am is of major concern due to high affinity for organic matter and high specific activity. This study examines the dose-dependent biological effects of α-radiation delivered by (241)Am at the morphological, physiological and molecular level in 14-day old seedlings of Arabidopsis thaliana after hydroponic exposure for 4 or 7 days. Our results show that (241)Am has high transfer to the roots but low translocation to the shoots. In the roots, we observed a transcriptional response of reactive oxygen species scavenging and DNA repair pathways. At the physiological and morphological level this resulted in a response which evolved from redox balance control and stable biomass at low dose rates to growth reduction, reduced transfer and redox balance decline at higher dose rates. This situation was also reflected in the shoots where, despite the absence of a transcriptional response, the control of photosynthesis performance and redox balance declined with increasing dose rate. The data further suggest that the effects in both organs were initiated in the roots, where the highest dose rates occurred, ultimately affecting photosynthesis performance and carbon assimilation. Though further detailed study of nutrient balance and (241)Am localisation is necessary, it is clear that radionuclide uptake and distribution is a major parameter in the global exposure effects on plant performance and health., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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35. Predicting radiocaesium sorption characteristics with soil chemical properties for Japanese soils.
- Author
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Uematsu S, Smolders E, Sweeck L, Wannijn J, Van Hees M, and Vandenhove H
- Subjects
- Adsorption, Aluminum Silicates chemistry, Cesium Radioisotopes chemistry, Clay, Japan, Minerals chemistry, Soil Pollutants, Radioactive chemistry, Cesium Radioisotopes analysis, Soil chemistry, Soil Pollutants, Radioactive analysis
- Abstract
The high variability of the soil-to-plant transfer factor of radiocaesium (RCs) compels a detailed analysis of the radiocaesium interception potential (RIP) of soil, which is one of the specific factors ruling the RCs transfer. The range of the RIP values for agricultural soils in the Fukushima accident affected area has not yet been fully surveyed. Here, the RIP and other major soil chemical properties were characterised for 51 representative topsoils collected in the vicinity of the Fukushima contaminated area. The RIP ranged a factor of 50 among the soils and RIP values were lower for Andosols compared to other soils, suggesting a role of soil mineralogy. Correlation analysis revealed that the RIP was most strongly and negatively correlated to soil organic matter content and oxalate extractable aluminium. The RIP correlated weakly but positively to soil clay content. The slope of the correlation between RIP and clay content showed that the RIP per unit clay was only 4.8 mmol g(-1) clay, about threefold lower than that for clays of European soils, suggesting more amorphous minerals and less micaceous minerals in the clay fraction of Japanese soils. The negative correlation between RIP and soil organic matter may indicate that organic matter can mask highly selective sorption sites to RCs. Multiple regression analysis with soil organic matter and cation exchange capacity explained the soil RIP (R(2)=0.64), allowing us to map soil RIP based on existing soil map information., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
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36. Induction of Oxidative Stress and Antioxidative Mechanisms in Arabidopsis thaliana after Uranium Exposure at pH 7.5.
- Author
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Saenen E, Horemans N, Vanhoudt N, Vandenhove H, Biermans G, Van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Arabidopsis metabolism, Arabidopsis Proteins metabolism, Dose-Response Relationship, Drug, Gene Expression Regulation, Plant drug effects, Hydrogen-Ion Concentration, Oxidative Stress, Plant Leaves drug effects, Plant Leaves metabolism, Plant Roots drug effects, Plant Roots metabolism, Antioxidants metabolism, Arabidopsis drug effects, Ascorbic Acid metabolism, Glutathione metabolism, Uranium pharmacology
- Abstract
To evaluate the environmental impact of uranium (U) contamination, it is important to investigate the effects of U at ecologically relevant conditions. Since U speciation, and hence its toxicity, strongly depends on environmental pH, the present study aimed to investigate dose-dependent effects of U at pH 7.5. Arabidopsis thaliana plants (Mouse-ear Cress) were exposed for three days to different U concentrations at pH 7.5. In the roots, the increased capacities of ascorbate peroxidase and glutathione reductase indicate an important role for the ascorbate-glutathione cycle during U-induced stress. However, a significant decrease in the ascorbate redox state was observed after exposure to 75 and 100 µM U, indicating that those roots are severely stressed. In accordance with the roots, the ascorbate-glutathione cycle plays an important role in the antioxidative defence systems in A. thaliana leaves exposed to U at pH 7.5 as the ascorbate and glutathione biosynthesis were upregulated. In addition, small inductions of enzymes of the antioxidative defence system were observed at lower U concentrations to counteract the U-induced stress. However, at higher U concentrations it seems that the antioxidative defence system of the leaves collapses as reductions in enzyme activities and gene expression levels were observed.
- Published
- 2015
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37. Comparison of two sequential extraction procedures for uranium fractionation in contaminated soils.
- Author
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Vandenhove H, Vanhoudt N, Duquène L, Antunes K, and Wannijn J
- Subjects
- Reproducibility of Results, Soil chemistry, Chemical Fractionation methods, Lolium metabolism, Soil Pollutants, Radioactive analysis, Soil Pollutants, Radioactive metabolism, Uranium analysis, Uranium metabolism
- Abstract
Two sequential extraction procedures were carried out on six soils with different chemical properties and contamination history to estimate the partitioning of uranium (U) between different soil fractions. The first standard method (method of Schultz) was specifically developed for actinides, while the second one (method of Rauret) was initially created for heavy metals. Reproducibility of both methods was compared by means of the coefficient of variation (CV). A soil-to-plant transfer experiment was also carried out with ryegrass to verify if one of the extracted fractions efficiently predicted plant uptake. In artificially contaminated soils, most of the U was retrieved from the exchangeable and the carbonates fractions. In soils with high natural levels of U or contaminated by industrial activity, most of the U was found in the less available fractions. Different U concentrations were found in the fractions which were supposed to be comparable in the two methods. Extracted fractions following Schultz differentiated more strongly between the tested soils but no relationships with soil parameters could be established. As expected, the highest U transfer factors (TF) were observed for ryegrass grown on artificially contaminated soils and the lowest on soils with high natural concentrations or industrial contamination, in agreement with the extraction procedures. No good relation was found between the soil-to-shoot TF and the extracted U concentrations. On the other hand, the U concentration in the roots, the U concentration in the shoots and the soil-to-root TF are well correlated to the U concentration determined in the first extracted fractions (so called exchangeable fractions) from the method of Schultz. We conclude that the extraction method according to Schultz should be preferably used for U, and that the exchangeable fraction can be proposed as a potential indicator to evaluate plant uptake in soils., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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38. The pH strongly influences the uranium-induced effects on the photosynthetic apparatus of Arabidopsis thaliana plants.
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Saenen E, Horemans N, Vanhoudt N, Vandenhove H, Biermans G, Van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Hydrogen-Ion Concentration, Arabidopsis drug effects, Arabidopsis metabolism, Photosynthesis drug effects, Plant Roots drug effects, Plant Roots metabolism, Uranium pharmacology
- Abstract
To study the impact of environmental uranium (U) contamination, effects should be analysed at different environmentally relevant pH levels as the speciation of U, and hence its toxicity, is strongly dependent on the pH. As photosynthesis is a major energy producing process in plants intimately connected to plant growth and known to be susceptible to metal stress, the effects of different U concentrations on photosynthesis in 18-day-old Arabidopsis thaliana (Columbia ecotype) are investigated at two contrasting pH levels, pH 4.5 and pH 7.5. At pH 4.5, U is highly taken up by the roots but is poorly translocated to the shoots, while at pH 7.5, less U is taken up but the translocation is higher. The lower U concentrations in the shoots at pH 4.5 are accompanied by a more reduced leaf growth as compared to pH 7.5. In addition, U does not influence the photosynthetic machinery at pH 7.5, while an optimization of the photosynthesis takes place after U exposure at pH 4.5. As such, more of the absorbed quanta are effectively used for photosynthesis accompanied by a decreased non-photochemical quenching and an increased electron transport rate. Since the enhanced photosynthesis at pH 4.5 is accompanied by a decreased growth, we suggest that the energy produced during photosynthesis is used for defence reactions against U-induced oxidative stress rather than for growth. As such, a high discrepancy was observed between the two pH levels, with an optimized photosynthetic apparatus at pH 4.5 and almost no effects at pH 7.5., (Copyright © 2014. Published by Elsevier Masson SAS.)
- Published
- 2014
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39. An organ-based approach to dose calculation in the assessment of dose-dependent biological effects of ionising radiation in Arabidopsis thaliana.
- Author
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Biermans G, Horemans N, Vanhoudt N, Vandenhove H, Saenen E, Van Hees M, Wannijn J, Vives i Batlle J, and Cuypers A
- Subjects
- Alpha Particles adverse effects, Beta Particles adverse effects, Dose-Response Relationship, Radiation, Gamma Rays adverse effects, Arabidopsis radiation effects, Radiation, Ionizing, Radioisotopes adverse effects
- Abstract
There is a need for a better understanding of biological effects of radiation exposure in non-human biota. Correct description of these effects requires a more detailed model of dosimetry than that available in current risk assessment tools, particularly for plants. In this paper, we propose a simple model for dose calculations in roots and shoots of Arabidopsis thaliana seedlings exposed to radionuclides in a hydroponic exposure setup. This model is used to compare absorbed doses for three radionuclides, (241)Am (α-radiation), (90)Sr (β-radiation) and (133)Ba (γ radiation). Using established dosimetric calculation methods, dose conversion coefficient values were determined for each organ separately based on uptake data from the different plant organs. These calculations were then compared to the DCC values obtained with the ERICA tool under equivalent geometry assumptions. When comparing with our new method, the ERICA tool appears to overestimate internal doses and underestimate external doses in the roots for all three radionuclides, though each to a different extent. These observations might help to refine dose-response relationships. The DCC values for (90)Sr in roots are shown to deviate the most. A dose-effect curve for (90)Sr β-radiation has been established on biomass and photosynthesis endpoints, but no significant dose-dependent effects are observed. This indicates the need for use of endpoints at the molecular and physiological scale., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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40. Primary stress responses in Arabidopsis thaliana exposed to gamma radiation.
- Author
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Vanhoudt N, Horemans N, Wannijn J, Nauts R, Van Hees M, and Vandenhove H
- Subjects
- Arabidopsis growth & development, Arabidopsis metabolism, Carotenoids metabolism, Catalase metabolism, Chlorophyll metabolism, Chlorophyll A, Peroxidases metabolism, Photosynthesis radiation effects, Plant Leaves growth & development, Plant Leaves metabolism, Plant Leaves radiation effects, Plant Roots growth & development, Plant Roots metabolism, Plant Roots radiation effects, Stress, Physiological physiology, Superoxide Dismutase metabolism, Arabidopsis radiation effects, Gamma Rays adverse effects
- Abstract
As the environment is inevitably exposed to ionizing radiation from natural and anthropogenic sources, it is important to evaluate gamma radiation induced stress responses in plants. The objective of this research is therefore to investigate radiation effects in Arabidopsis thaliana on individual and subcellular level by exposing 2-weeks-old seedlings for 7 days to total doses of 3.9 Gy, 6.7 Gy, 14.8 Gy and 58.8 Gy and evaluating growth, photosynthesis, chlorophyll a, chlorophyll b and carotenoid concentrations and antioxidative enzyme capacities. While the capacity of photosystem II (PSII measured as Fv/Fm) remained intact, plants started optimizing their photosynthetic process at the lower radiation doses by increasing the PSII efficiency (φPSII) and the maximal electron transport rate (ETRmax) and by decreasing the non-photochemical quenching (NPQ). At the highest radiation dose, photosynthetic parameters resembled those of control conditions. On subcellular level, roots showed increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) capacities under gamma irradiation but catalase (CAT), syringaldazine peroxidase (SPX) and guaiacol peroxidase (GPX) activities, on the other hand, decreased. In the leaves no alterations were observed in SOD, CAT and SPX capacities, but GPX was highly affected. Based on these results it seems that roots are more sensitive for oxidative stress under gamma radiation exposure than leaves., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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41. Effects of pH on uranium uptake and oxidative stress responses induced in Arabidopsis thaliana.
- Author
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Saenen E, Horemans N, Vanhoudt N, Vandenhove H, Biermans G, Van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Antioxidants metabolism, Arabidopsis metabolism, Glutathione metabolism, Hydrogen-Ion Concentration, Plant Leaves drug effects, Plant Leaves metabolism, Plant Roots drug effects, Plant Roots metabolism, Seedlings drug effects, Seedlings metabolism, Superoxide Dismutase metabolism, Uranium pharmacology, Arabidopsis drug effects, Oxidative Stress drug effects, Uranium metabolism
- Abstract
Uranium (U) causes oxidative stress in Arabidopsis thaliana plants grown at pH 5.5. However, U speciation and its toxicity strongly depend on environmental parameters, for example pH. It is unknown how different U species determine U uptake and translocation within plants and how they might affect the oxidative defense mechanisms of these plants. The present study analyzed U uptake and oxidative stress-related responses in A. thaliana (Columbia ecotype) under contrasted U chemical speciation conditions. The 18-d-old seedlings were exposed for 3 d to 25 µM U in a nutrient solution of which the pH was adjusted to 4.5, 5.5, 6.5, or 7.5. Results indicate that there is a different rate of U uptake and translocation at the different pHs, with high uptake and low translocation at low pH and lower uptake but higher translocation at high pH. After U exposure, an increased glutathione reductase activity and total glutathione concentration were observed in U-exposed roots, pointing toward an important role for glutathione in the root defense system against U either by chelation or by antioxidative defense mechanisms. In leaves, antioxidative defense mechanisms were activated on U exposure, indicated by increased superoxide dismutase and catalase activity. As it seems that U toxicity is influenced by pH, it is important to consider site-specific characteristics when making U risk assessments., (Copyright © 2013 SETAC.)
- Published
- 2013
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42. Unraveling uranium induced oxidative stress related responses in Arabidopsis thaliana seedlings. Part II: responses in the leaves and general conclusions.
- Author
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Vanhoudt N, Cuypers A, Horemans N, Remans T, Opdenakker K, Smeets K, Bello DM, Havaux M, Wannijn J, Van Hees M, Vangronsveld J, and Vandenhove H
- Subjects
- Antioxidants metabolism, Arabidopsis drug effects, Arabidopsis growth & development, Ascorbic Acid metabolism, Gene Expression, Glutathione metabolism, Hydrogen Peroxide metabolism, Lipid Peroxidation, Oxidation-Reduction, Oxidoreductases metabolism, Plant Leaves drug effects, Plant Leaves growth & development, Plant Leaves metabolism, Plant Roots drug effects, Plant Roots growth & development, Plant Roots metabolism, Radiation Dosage, Reactive Oxygen Species metabolism, Seedlings drug effects, Seedlings growth & development, Seedlings metabolism, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Oxidative Stress, Uranium toxicity
- Abstract
The cellular redox balance seems an important modulator under heavy metal stress. While for other heavy metals these processes are well studied, oxidative stress related responses are also known to be triggered under uranium stress but information remains limited. This study aimed to further unravel the mechanisms by which plants respond to uranium stress. Seventeen-day-old Arabidopsis thaliana seedlings, grown on a modified Hoagland solution under controlled conditions, were exposed to 0, 0.1, 1, 10 and 100 μM uranium for 1, 3 and 7 days. While in Part I of this study oxidative stress related responses in the roots were discussed, this second Part II discusses oxidative stress related responses in the leaves and general conclusions drawn from the results of the roots and the leaves will be presented. As several responses were already visible following 1 day exposure, when uranium concentrations in the leaves were negligible, a root-to-shoot signaling system was suggested in which plastids could be important sensing sites. While lipid peroxidation, based on the amount of thiobarbituric acid reactive compounds, was observed after exposure to 100 μM uranium, affecting membrane structure and function, a transient concentration dependent response pattern was visible for lipoxygenase initiated lipid peroxidation. This transient character of uranium stress responses in leaves was emphasized by results of lipoxygenase (LOX2) and antioxidative enzyme transcript levels, enzyme capacities and glutathione concentrations both in time as with concentration. The ascorbate redox balance seemed an important modulator of uranium stress responses in the leaves as in addition to the previous transient responses, the total ascorbate concentration and ascorbate/dehydroascorbate redox balance increased in a concentration and time dependent manner. This could represent either a slow transient response or a stable increase with regard to plant acclimation to uranium stress., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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43. Unraveling uranium induced oxidative stress related responses in Arabidopsis thaliana seedlings. Part I: responses in the roots.
- Author
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Vanhoudt N, Vandenhove H, Horemans N, Remans T, Opdenakker K, Smeets K, Bello DM, Wannijn J, Van Hees M, Vangronsveld J, and Cuypers A
- Subjects
- Arabidopsis drug effects, Arabidopsis growth & development, Ascorbic Acid metabolism, Gene Expression, Glutathione metabolism, Hydrogen Peroxide metabolism, Oxidation-Reduction, Oxidoreductases metabolism, Plant Roots drug effects, Plant Roots growth & development, Plant Roots metabolism, Radiation Dosage, Reactive Oxygen Species metabolism, Seedlings drug effects, Seedlings growth & development, Seedlings metabolism, Antioxidants metabolism, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Oxidative Stress, Uranium toxicity
- Abstract
When aiming to evaluate the environmental impact of uranium contamination, it is important to unravel the mechanisms by which plants respond to uranium stress. As oxidative stress seems an important modulator under other heavy metal stress, this study aimed to investigate oxidative stress related responses in Arabidopsis thaliana exposed to uranium concentrations ranging from 0.1 to 100 μM for 1, 3 and 7 days. Besides analyzing relevant reactive oxygen species-producing and -scavenging enzymes at protein and transcriptional level, the importance of the ascorbate-glutathione cycle under uranium stress was investigated. These results are reported separately for roots and leaves in two papers: Part I dealing with responses in the roots and Part II unraveling responses in the leaves and presenting general conclusions. Results of Part I indicate that oxidative stress related responses in the roots were only triggered following exposure to the highest uranium concentration of 100 μM. A fast oxidative burst was suggested based on the observed enhancement of lipoxygenase (LOX1) and respiratory burst oxydase homolog (RBOHD) transcript levels already after 1 day. The first line of defense was attributed to superoxide dismutase (SOD), also triggered from the first day. The enhanced SOD-capacity observed at protein level corresponded with an enhanced expression of iron SOD (FSD1) located in the plastids. For the detoxification of H(2)O(2), an early increase in catalase (CAT1) transcript levels was observed while peroxidase capacities were enhanced at the later stage of 3 days. Although the ascorbate peroxidase capacity and gene expression (APX1) increased, the ascorbate/dehydroascorbate redox balance was completely disrupted and shifted toward the oxidized form. This disrupted balance could not be inverted by the glutathione part of the cycle although the glutathione redox balance could be maintained., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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44. The combined effect of uranium and gamma radiation on biological responses and oxidative stress induced in Arabidopsis thaliana.
- Author
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Vanhoudt N, Vandenhove H, Horemans N, Wannijn J, Van Hees M, Vangronsveld J, and Cuypers A
- Subjects
- Antioxidants metabolism, Arabidopsis growth & development, Arabidopsis physiology, Arabidopsis Proteins metabolism, Lipid Peroxidation radiation effects, Plant Leaves metabolism, Plant Leaves radiation effects, Plant Roots metabolism, Plant Roots radiation effects, RNA, Messenger metabolism, Reactive Oxygen Species metabolism, Seedlings physiology, Seedlings radiation effects, Superoxide Dismutase metabolism, Arabidopsis radiation effects, Gamma Rays, Oxidative Stress, Uranium
- Abstract
Uranium never occurs as a single pollutant in the environment, but always in combination with other stressors such as ionizing radiation. As effects induced by multiple contaminants can differ markedly from the effects induced by the individual stressors, this multiple pollution context should not be neglected. In this study, effects on growth, nutrient uptake and oxidative stress induced by the single stressors uranium and gamma radiation are compared with the effects induced by the combination of both stressors. By doing this, we aim to better understand the effects induced by the combined stressors but also to get more insight in stressor-specific response mechanisms. Eighteen-day-old Arabidopsis thaliana seedlings were exposed for 3 days to 10 muM uranium and 3.5 Gy gamma radiation. Gamma radiation interfered with uranium uptake, resulting in decreased uranium concentrations in the roots, but with higher transport to the leaves. This resulted in a better root growth but increased leaf lipid peroxidation. For the other endpoints studied, effects under combined exposure were mostly determined by uranium presence and only limited influenced by gamma presence. Furthermore, an important role is suggested for CAT1/2/3 gene expression under uranium and mixed stressor conditions in the leaves.
- Published
- 2010
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45. Study of oxidative stress related responses induced in Arabidopsis thaliana following mixed exposure to uranium and cadmium.
- Author
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Vanhoudt N, Vandenhove H, Horemans N, Wannijn J, Bujanic A, Vangronsveld J, and Cuypers A
- Subjects
- Arabidopsis genetics, Ascorbic Acid metabolism, Cadmium metabolism, Gene Expression, Glutathione metabolism, Hydrogen Peroxide, Hydroponics, Micronutrients metabolism, Oxidation-Reduction, Oxidative Stress genetics, Plant Structures metabolism, Seedlings metabolism, Superoxide Dismutase genetics, Superoxide Dismutase metabolism, Superoxides metabolism, Uranium metabolism, Adaptation, Physiological genetics, Antioxidants metabolism, Arabidopsis metabolism, Cadmium toxicity, Genes, Plant, Oxidative Stress drug effects, Uranium toxicity
- Abstract
In this study, toxicity effects in plants of uranium in a binary pollution condition were investigated by studying biological responses and unraveling oxidative stress related mechanisms in Arabidopsis thaliana seedlings, grown on hydroponics and exposed for 3 days to 10 μM uranium in combination with 5 μM cadmium. While uranium mostly accumulated in the roots with very low root-to-shoot transport, cadmium was taken up less by the roots but showed higher translocation to the shoots. Under mixed exposure, cadmium influenced uranium uptake highly but not the other way round resulting in a doubled uranium concentration in the roots. Under our mixed exposure conditions, it is clear that micronutrient concentrations in the roots are strongly influenced by addition of cadmium as a second stressor, while leaf macronutrient concentrations are mostly influenced by uranium. Oxidative stress related responses are highly affected by cadmium while uranium influence is more limited. Hereby, an important role was attributed to the ascorbate redox balance together with glutathione as both metabolites, but more explicitly for ascorbate, increased their reduced form, indicating an important defense and regulatory function. While for roots, based on an increase in FSD1 gene expression, oxidative stress was suggested to be superoxide induced, in leaves on the other hand, hydrogen peroxide related genes were mostly altered., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)
- Published
- 2010
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46. Life-cycle chronic gamma exposure of Arabidopsis thaliana induces growth effects but no discernable effects on oxidative stress pathways.
- Author
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Vandenhove H, Vanhoudt N, Cuypers A, van Hees M, Wannijn J, and Horemans N
- Subjects
- Arabidopsis genetics, Arabidopsis metabolism, Ascorbate Peroxidases, Ascorbic Acid metabolism, Catalase metabolism, Comet Assay, DNA, Plant analysis, DNA, Plant genetics, Dose-Response Relationship, Radiation, Gene Expression Regulation, Plant radiation effects, Glutathione metabolism, Glutathione Reductase metabolism, Lipid Peroxidation radiation effects, Peroxidase metabolism, Peroxidases metabolism, Plant Leaves genetics, Plant Leaves growth & development, Plant Leaves metabolism, Plant Proteins metabolism, Plant Roots genetics, Plant Roots growth & development, Plant Roots metabolism, Reactive Oxygen Species metabolism, Reverse Transcriptase Polymerase Chain Reaction, Superoxide Dismutase metabolism, Arabidopsis growth & development, Gamma Rays, Oxidative Stress radiation effects, Signal Transduction radiation effects
- Abstract
Arabidopsis thaliana was exposed to low-dose chronic gamma irradiation during a full life cycle (seed to seed) and several biological responses were investigated. Applied dose rates were 2336, 367 and 81 microGy h(-1). Following 24 days (inflorescence emergence), 34 days (approximately 50% of flowers open) and 54 days (silice ripening) exposure, plants were harvested and monitored for biometric parameters, capacities of enzymes involved in the antioxidative defence mechanisms (SOD, APOD, GLUR, GPOD, SPOD, CAT, ME), glutathione and ascorbate pool, lipid peroxidation products, altered gene expression of selected genes encoding for antioxidative enzymes or reactive oxygen species production, and DNA integrity. Root fresh weight was significantly reduced after gamma exposure compared to the control at all stages monitored but no significant differences in root weight for the different dose rates applied was observed. Leaf and stem fresh weight were significantly reduced at the highest irradiation level after 54 days exposure only. Also total plant fresh was significantly lower at silice riping and this for the highest and medium dose rate applied. The dose rate estimated to result in a 10% reduction in growth (EDR-10) ranged between 60 and 80 microGy h(-1). Germination of seeds from the gamma irradiated plants was not hampered. For several of the antioxidative defence enzymes studied, the enzyme capacity was generally stimulated towards flowering but generally no significant effect of dose rate on enzyme capacity was observed. Gene analysis revealed a significant transient and dose dependent change in expression of RBOHC indicating active reactive oxygen production induced by gamma irradiation. No effect of irradiation was observed on concentration or reduction state of the non-enzymatic antioxidants, ascorbate and glutathione. The level of lipid peroxidation products remained constant throughout the observation period and was not affected by dose rate. The comet assay did not reveal any effect of gamma dose rate on DNA integrity., (2010 Elsevier Masson SAS. All rights reserved.)
- Published
- 2010
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47. Radiocesium transfer between Medicago truncatula plants via a common mycorrhizal network.
- Author
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Gyuricza V, Thiry Y, Wannijn J, Declerck S, and Dupré de Boulois H
- Subjects
- Cesium Radioisotopes metabolism, Hyphae growth & development, Hyphae metabolism, Mycorrhizae growth & development, Plant Roots metabolism, Plant Roots microbiology, Cesium metabolism, Medicago truncatula metabolism, Medicago truncatula microbiology, Mycorrhizae metabolism
- Abstract
Common mycorrhizal networks of arbuscular mycorrhizal fungi have been reported to transfer cesium between plants. However, a direct hyphae-mediated transfer (via cytoplasm/protoplasm) cannot be distinguished from an indirect transfer. Indeed, cesium released by the roots of the donor plant can be taken up by the receiver plant or fungal hyphae. In the present study, Medicago truncatula plants were connected by a common mycorrhizal network and Prussian Blue (ammonium-ferric-hexacyano ferrate) was added in the growth medium to adsorb the released radiocesium. A direct transfer of radiocesium to roots and shoots of the receiver plant was clearly demonstrated for the first time. Even though this transfer was quantitatively low, it suggested that shared mycorrhizal networks could contribute to the redistribution of this radionuclide in the environment, which otherwise would be restricted both in time and space. This finding may also help to understand the behaviour of its chemical analogue, potassium., (© 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.)
- Published
- 2010
- Full Text
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48. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots.
- Author
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Straczek A, Duquene L, Wegrzynek D, Chinea-Cano E, Wannijn J, Navez J, and Vandenhove H
- Subjects
- Biomass, Cell Wall metabolism, Cotyledon metabolism, Dose-Response Relationship, Radiation, Mustard Plant metabolism, Plant Roots growth & development, Seeds metabolism, Triticum metabolism, Zea mays metabolism, Plant Roots metabolism, Plant Shoots metabolism, Uranium metabolism
- Abstract
Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 micromol U L(-1), distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot., (2009 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
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49. Effects of uranium and phosphate concentrations on oxidative stress related responses induced in Arabidopsis thaliana.
- Author
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Vanhoudt N, Vandenhove H, Smeets K, Remans T, Van Hees M, Wannijn J, Vangronsveld J, and Cuypers A
- Subjects
- Arabidopsis growth & development, Arabidopsis metabolism, Gene Expression, Lipid Peroxidation, Oxidative Stress physiology, Plant Leaves drug effects, Plant Leaves growth & development, Plant Roots drug effects, Plant Roots growth & development, Reactive Oxygen Species metabolism, Seedlings drug effects, Seedlings growth & development, Antioxidants physiology, Arabidopsis drug effects, Oxidative Stress drug effects, Phosphates toxicity, Uranium toxicity
- Abstract
The production of reactive oxygen species (ROS) and the induction of the antioxidative defense mechanism are very important in heavy metal toxicity. In this study, biological effects induced after uranium contamination were investigated for Arabidopsis thaliana. Three-week-old seedlings were exposed for 4days to 100microM U in an adjusted Hoagland solution. Uranium exposure caused a decreased growth of leaves (38%) and roots (70%) and a modified nutrient profile was observed. Investigation of lipid peroxidation products indicated a significant increase of membrane damage. Important ROS-producing and -scavenging enzymes were studied at transcriptional and protein level to investigate the importance of the ROS-signature in uranium toxicity. Elevated gene expression was observed for NADPH-oxidase, a ROS-producing enzyme. Changes in gene expression for different ROS-scavenging enzymes as Cu/ZnSOD, FeSOD and APX were also observed. Analysis of enzyme capacities showed little effects after uranium contamination. Higher ascorbate levels in uranium exposed leaves suggested an increase of antioxidative defense via the ascorbate-glutathione pathway after uranium exposure. Theoretical calculations indicated rapid formation of uranium-phosphate precipitates if normal phosphate concentrations are used. Precipitation tests recommend the use of 25microM P in combination with 100microM U to inhibit uranium precipitation. Because this combination was used for uranium toxicity investigation, the influence of this low phosphate concentration on plant growth and oxidative stress had to be evaluated. Minor differences between low phosphate (25microM P) and high phosphate (100microM P) treatments were observed justifying the use of the low phosphate concentration in combination with uranium.
- Published
- 2008
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50. Effects of phosphorus fertilization on the availability and uptake of uranium and nutrients by plants grown on soil derived from uranium mining debris.
- Author
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Rufyikiri G, Wannijn J, Wang L, and Thiry Y
- Subjects
- Biodegradation, Environmental, Calcium analysis, Hazardous Waste, Magnesium analysis, Mining, Plant Development, Plant Roots chemistry, Plant Shoots chemistry, Potassium analysis, Environmental Restoration and Remediation methods, Fertilizers analysis, Phosphorus analysis, Plants metabolism, Soil Pollutants, Radioactive analysis, Soil Pollutants, Radioactive pharmacokinetics, Uranium analysis, Uranium pharmacokinetics
- Abstract
Subterranean clover and barley were grown on a soil derived from uranium mining debris and fertilized with phosphate as a U immobilizing additive for in situ remediation. We investigated the beneficial effect of P fertilization in the range 0-500 mg P kg(-1) soil in terms of U extractability, plant biomass production and U uptake. Increasing P in the mining debris caused a significant decrease of the water-soluble U and NH(4)-Ac extractable U at pH 7 and 5. For both plant species, P fertilization considerably increased root and shoot dry matter up to a maximum observed for soil receiving 100 mg P kg(-1) while the soil-to-plant transfer of U was regularly decreased by increasing P content in soil. These observations show that P fertilization represents an in situ practical option to facilitate the revegetation of U-mining heaps and to reduce the risks of biota exposure to U contamination.
- Published
- 2006
- Full Text
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