Application of Quantitative Fluorescence and Absorption-Edge Computed Microtomography to Image Metal Compartmentalization in <i>Alyssum murale</i>

McNear, David H.; Peltier, Edward; Everhart, Jeff; Chaney, Rufus L.; Sutton, S.R.; Newville, Matt; Rivers, Mark L.; Sparks, Donald L.

doi:10.1021/es0492034

Cited by 178 publications

(138 citation statements)

References 49 publications

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“…XRF intensities were collected using a 16-element Ge detector. The resulting two-dimensional sine wave plots were reconstructed as described in McNear et al (2005).…”

Section: Fluorescence Microtomographymentioning

confidence: 99%

Grain Unloading of Arsenic Species in Rice

et al. 2009

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Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a 6 stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.

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“…XRF intensities were collected using a 16-element Ge detector. The resulting two-dimensional sine wave plots were reconstructed as described in McNear et al (2005).…”

Section: Fluorescence Microtomographymentioning

confidence: 99%

Grain Unloading of Arsenic Species in Rice

et al. 2009

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“…Elemental abundances (percentage weight fraction) were calculated for the fluorescence measurements, adapted from a description by McNear et al (2005). Briefly, a thin-film standard reference material (SRM 1833) was measured prior to the collection of each data set to establish elemental sensitivities (counts per second per mg cm 22 ) for Fe.…”

Section: Abundance Quantification and Postprocessing Of Sxrf Tomograpmentioning

confidence: 99%

The Role of CAX1 and CAX3 in Elemental Distribution and Abundance in Arabidopsis Seed

et al. 2012

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The ability to alter nutrient partitioning within plants cells is poorly understood. In Arabidopsis (Arabidopsis thaliana), a family of endomembrane cation exchangers (CAXs) transports Ca 2+ and other cations. However, experiments have not focused on how the distribution and partitioning of calcium (Ca) and other elements within seeds are altered by perturbed CAX activity. Here, we investigate Ca distribution and abundance in Arabidopsis seed from cax1 and cax3 loss-of-function lines and lines expressing deregulated CAX1 using synchrotron x-ray fluorescence microscopy. We conducted 7-to 10-mm resolution in vivo x-ray microtomography on dry mature seed and 0.2-mm resolution x-ray microscopy on embryos from lines overexpressing deregulated CAX1 (35S-sCAX1) and cax1cax3 double mutants only. Tomograms showed an increased concentration of Ca in both the seed coat and the embryo in cax1, cax3, and cax1cax3 lines compared with the wild type. High-resolution elemental images of the mutants showed that perturbed CAX activity altered Ca partitioning within cells, reducing Ca partitioning into organelles and/or increasing Ca in the cytosol and abolishing tissue-level Ca gradients. In comparison with traditional volume-averaged metal analysis, which confirmed subtle changes in seed elemental composition, the collection of spatially resolved data at varying resolutions provides insight into the impact of altered CAX activity on seed metal distribution and indicates a cell type-specific function of CAX1 and CAX3 in partitioning Ca into organelles. This work highlights a powerful technology for inferring transport function and quantifying nutrient changes.

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“…The advent of analytical instrumentation such as proton induced Xray emission (PIXE), X-ray absorption spectroscopy (XAS) and synchrotron X-ray fluorescence (SXRF) spectroscopy has made it possible to observe and accurately describe the form and distribution of metals within a plant (Mesjasz-Przybylowicz et al, 2001a, 2001bMcNear et al, 2005) and valence state and size of the accumulated metal NPs (Narayanan and Sakthivel, 2011).…”

Section: Phyto-synthesis Of Metal Nanoparticlesmentioning

confidence: 99%

Synthesis of metal nanoparticles in living plants

Marchiol

2012

Ital J Agronomy

103

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In recent years, nanotechnologies have evolved from a multidisciplinary research concept to a primary scientific field. Rapid growth of new technologies has led to the development of nanoscale device components, advanced sensors, and novel biomimetic materials. In addition to chemical and physical approaches a new, simple and cheaper strategy to synthesize metal nanoparticles utilizes biological tools such as bacteria, yeasts, fungi, and plants. The majority of research has investigated ex vivo synthesis of nanoparticles in plants, proving that this method is very cost effective, and can therefore be used as an economic and valuable alternative for the large-scale production of metal nanoparticles. Instead, very few studies have been devoted to investigating the potential of living plants. The synthesis of metal nanoparticles using living plants is discussed in this review. So far, metal NPs formation in living plants has been observed for gold, silver, copper and zinc oxide. To date the results achieved demonstrate the feasibility of this process; however several aspects of the plant physiology involved should be clarified in order to be able to gain better control and modulate the formation of these new materials. Plant sciences could significantly contribute to fully exploring the potential of phyto-synthesis of metal nanoparticles.

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Application of Quantitative Fluorescence and Absorption-Edge Computed Microtomography to Image Metal Compartmentalization in Alyssum murale

Cited by 178 publications

References 49 publications

Grain Unloading of Arsenic Species in Rice

Grain Unloading of Arsenic Species in Rice

The Role of CAX1 and CAX3 in Elemental Distribution and Abundance in Arabidopsis Seed

Synthesis of metal nanoparticles in living plants

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