Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2012
Abstract
Residues of pharmaceuticals present in wastewater and sewage sludge are of concern due to their transfer to aquatic- and terrestrial food chains and possible adverse effects on non-targeted organisms. In the present work, uptake and translocation of metformin, an anti-diabetic II medicine, by edible plant species cultivated in agricultural soil has been investigated in greenhouse experiment. Metformin demonstrated a high uptake and translocation to oily seeds of rape (Brassica napus cv. Sheik and Brassica rapa cv. Valo). Expressed as an average bioconcentration factor, (BCF, plant concentration over initial concentration in soil, both in dry weight), BCF as high as 21.72 was measured. In comparison, BCFs for grains of the cereals wheat, barley and oat were in the range of 0.29 - 1.35. Uptake and translocation to fruits and vegetables of tomato (BCFs 0.02-0.06), squash (BCFs 0.12-0.18) and bean (BCF 0.88) were also low compared to rape. BCFs for carrot, potato and leaf forage Brassica napus cv. Sola were similar (BCF 1-4). Guanylurea, a known degradation product of metformin by microorganisms in activated sludge, was found in seeds from barley, beans and potatoes. The mechanisms for transport of metformin and guanidine in plants are still unknown, whereas organic cation transporters (OCTs) in mammals are known to actively transport such compounds and may guide the way for further understanding of mechanisms also in plants.
Authors
Nina Elisabeth Nagy Harald Kvaalen Monica Fongen Carl Gunnar Fossdal Nicholas Clarke Halvor Solheim Ari HietalaAbstract
Pathogen challenge of tree sapwood induces the formation of reaction zones with antimicrobial properties such as elevated pH and cation content. Many fungi lower substrate pH by secreting oxalic acid, its conjugate base oxalate being a reductant as well as a chelating agent for cations. To examine the role of oxalic acid in pathogenicity of white-rot fungi, we conducted spatial quantification of oxalate, transcript levels of related fungal genes, and element concentrations in heartwood of Norway spruce challenged naturally by Heterobasidion parviporum. In the pathogen-compromised reaction zone, upregulation of an oxaloacetase gene generating oxalic acid coincided with oxalate and cation accumulation and presence of calcium oxalate crystals. The colonized inner heartwood showed trace amounts of oxalate. Moreover, fungal exposure to the reaction zone under laboratory conditions induced oxaloacetase and oxalate accumulation, whereas heartwood induced a decarboxylase gene involved in degradation of oxalate. The excess level of cations in defense xylem inactivates pathogen-secreted oxalate through precipitation and, presumably, only after cation neutralization can oxalic acid participate in lignocellulose degradation. This necessitates enhanced production of oxalic acid by H. parviporum. This study is the first to determine the true influence of white-rot fungi on oxalate crystal formation in tree xylem.
Authors
Aksel Bernhoft Mona Torp Per-Erik Clasen Anne-Kristin Løes Anja Bråthen KristoffersenAbstract
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Authors
Shahid Nadeem Sissel Hansen Marina Azzaroli Bleken Peter DörschAbstract
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Authors
André Macherius Trine Eggen Wilhelm Georg Lorenz Thorsten Reemtsma Ulrich Winkler Monika MoederAbstract
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Authors
Peter Lindblad Pia Lindberg Paulo Oliveira Karin Stensjö Thorsten HeidornAbstract
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No abstract has been registered