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* old and bolonia study programme


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Cadmium associates with oxalate in calcium oxalate crystals and competes with calcium for translocation to stems in the cadmium bioindicator Gomphrena claussenii
Paula Pongrac, Tania Serra, Hiram Castillo Michel, Katarina Vogel-Mikuš, Iztok Arčon, Mitja Klemen, Boštjan Jencic, Anja Kavčič, Mina T. Villafort Carvalho, Mark G. M. Aarts, 2018, original scientific article

Abstract: Cadmium (Cd) was shown to co-localise with calcium (Ca) in oxalate crystals in the stems and leaves of Cd tolerant Gomphrena claussenii, but Cd binding remained unresolved. Using synchrotron radiation X-ray absorption near edge spectroscopy we demonstrate that in oxalate crystals of hydroponically grown G. claussenii the vast majority of Cd is bound to oxygen ligands in oxalate crystals (488%; Cd–O–C coordination) and the remaining Cd is bound to sulphur ligands (Cd–S–C coordination). Cadmium binding to oxalate does not depend on the amount of Ca supplied or from which organs the crystals originate (stems and mature leaves). By contrast, roots contain no oxalate crystals and therein Cd is bound predominantly by S ligands. The potential to remove Cd by extraction of Cd-rich oxalate crystals from plant material should be tested in phytoextraction or phytomining strategies.
Found in: osebi
Keywords: Cd XANES, Cd oxalate, Gomphrena claussenii
Published: 06.09.2018; Views: 960; Downloads: 0
.pdf Fulltext (3,68 MB)

X-ray spectrometry in plant biology
Primož Pelicon, Peter Kump, Anja Kavčič, Alojz Kodre, Iztok Arčon, Katarina Vogel-Mikuš, 2018, published scientific conference contribution abstract (invited lecture)

Abstract: Trace elements are essential components of living systems, but at the same time they can be toxic at concentrations beyond those necessary for their biological functions. In addition, the toxicity can be extended to other non-essential elements of very similar atomic characteristics that can mimic the properties of a trace element. Trace element malnutrition affects more than half of the world’s population, while on the other hand industrialization, traffic and extensive use of fertilizers have resulted in exceedingly high concentrations of non-essential elements in food crops, posing risks to human health. In order to be able to develop and improve phyto-technologies that enable production of safe and quality food, knowledge on the basic mechanisms involved in trace and non-essential element uptake, transport, accumulation and ligand environment in plants is needed. Such studies are nowadays supported by highly sophisticated X-ray based techniques, such as synchrotron based X-ray fluorescence spectrometry, proton induced X-ray emission and X-ray absorption spectroscopy, enabling imaging of element distribution and determination of speciation and ligand environment of trace elements in biological tissues and cells with high spatial resolution and sensitivity. Selected case studies of metal distribution and speciation in selected model and crop plants, achieved by interdisciplinary work, will be presented.
Found in: osebi
Keywords: X-ray spectrometry, plants, XANES, EXAFS
Published: 12.09.2018; Views: 1086; Downloads: 0
.pdf Fulltext (62,44 KB)

Ionomic and metabolomic changes in mercury and selenium exposed plants and animals by X - ray and FTIR spectrometry
Katarina Vogel-Mikuš, Iztok Arčon, Jože Grdadolnik, Petra Gregorič, Anja Kavčič, 2018, published scientific conference contribution abstract

Found in: osebi
Keywords: mercury, selenium, plants, animals
Published: 12.09.2018; Views: 1203; Downloads: 0
.pdf Fulltext (62,45 KB)

Localization, ligand environment, bioavailability and toxicity of mercury in Boletus spp. and Scutiger pes-caprae mushrooms
Anja Kavčič, Klemen Mikuš, Marta Debeljak, Johannes Teun van Elteren, Iztok Arčon, Alojz Kodre, Peter Kump, Andreas-Germanos Karydas, Alessandro Migliori, Mateusz Czyzycki, Katarina Vogel-Mikuš, 2019, original scientific article

Abstract: This study provides information on mercury (Hg) localization, speciation and ligand environment in edible mushrooms: Boletus edulis, B. aereus and Scutiger pes-caprae collected at non-polluted and Hg polluted sites, by LA-ICP-MS, SR-μ-XRF and Hg L3-edge XANES and EXAFS. Mushrooms (especially young ones) collected at Hg polluted sites can contain more than 100 μg Hg g−1 of dry mass. Imaging of the element distribution shows that Hg accumulates mainly in the spore-forming part (hymenium) of the cap. Removal of hymenium before consumption can eliminate more than 50% of accumulated Hg. Mercury is mainly coordinated to di-thiols (43–82%), followed by di-selenols (13–35%) and tetra-thiols (12–20%). Mercury bioavailability, as determined by feeding the mushrooms to Spanish slugs (known metal bioindicators owing to accumulation of metals in their digestive gland), ranged from 4% (S. pes-caprae) to 30% (B. aereus), and decreased with increasing selenium (Se) levels in the mushrooms. Elevated Hg levels in mushrooms fed to the slugs induced toxic effects, but these effects were counteracted with increasing Se concentrations in the mushrooms, pointing to a protective role of Se against Hg toxicity through HgSe complexation. Nevertheless, consumption of the studied mushroom species from Hg polluted sites should be avoided.
Found in: osebi
Keywords: edible mushrooms, HgSe complex, imaging of elemental distribution, LA-ICP-MS, alpha-XRF, XAS
Published: 24.10.2019; Views: 922; Downloads: 0
.pdf Fulltext (1,79 MB)

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