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Hugh H. Harris

Bio: Hugh H. Harris is an academic researcher from University of Adelaide. The author has contributed to research in topics: Hyperaccumulator & Arsenate. The author has an hindex of 35, co-authored 118 publications receiving 4972 citations. Previous affiliations of Hugh H. Harris include University of Sydney & University of New Mexico.


Papers
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Journal ArticleDOI
29 Aug 2003-Science
TL;DR: The primary dietary source of neurotoxic mercury compounds is via the ingestion of methylmercury species accumulated in fish, which has been linked to neurological damage (Minamata disease) and increased risk of myocardial infarction.
Abstract: The primary dietary source of neurotoxic mercury compounds is via the ingestion of methylmercury species accumulated in fish. Methylmercury from fish has been linked to neurological damage (Minamata disease) ([ 1 ][1]) and increased risk of myocardial infarction ([ 2 ][2]). Despite its importance,

1,245 citations

Journal ArticleDOI
TL;DR: It is concluded that dietary selenium compounds should be considered prodrugs, whose biological activity will depend on the activity of the various metabolic pathways in, and the redox status of, cells and tissues.
Abstract: The biological activity of selenium is dependent upon its speciation We aim to integrate selenium speciation and metabolism into a discussion of the mechanisms by which selenium exerts its biological activity First, we present the current status of selenium in the prevention of cancer, cardiovascular and neurodegenerative diseases with particular attention paid to the results of major chemoprevention trials involving selenium supplementation A comprehensive review of the current understanding of the metabolism of common dietary selenium compounds – selenite, selenomethionine, methylselenocysteine and selenocystine – is presented, with discussion of the evidence for the various metabolic pathways and their products The antioxidant, prooxidant and other mechanisms of the dietary selenium compounds have been linked to their disease prevention and treatment properties The evidence for these various mechanisms – in vitro, in cells and in vivo – is evaluated with emphasis on the selenium metabolites involved We conclude that dietary selenium compounds should be considered prodrugs, whose biological activity will depend on the activity of the various metabolic pathways in, and the redox status of, cells and tissues These factors should be considered in future laboratory research and in selecting selenium compounds for trials of disease prevention and treatment by selenium supplementation

442 citations

Journal ArticleDOI
TL;DR: The results demonstrate the feasibility of developing transgenic plant-based production of Se-methylselenocysteine, as well as bioengineering selenite resistance in plants, and the engineering of Se tolerance in plants ideally suited for the phytoremediation of Se contaminated land.
Abstract: Background It has become increasingly evident that dietary Se plays a significant role in reducing the incidence of lung, colorectal and prostate cancer in humans. Different forms of Se vary in their chemopreventative efficacy, with Se-methylselenocysteine being one of the most potent. Interestingly, the Se accumulating plant Astragalus bisulcatus (Two-grooved poison vetch) contains up to 0.6% of its shoot dry weight as Se-methylselenocysteine. The ability of this Se accumulator to biosynthesize Se-methylselenocysteine provides a critical metabolic shunt that prevents selenocysteine and selenomethionine from entering the protein biosynthetic machinery. Such a metabolic shunt has been proposed to be vital for Se tolerance in A. bisulcatus. Utilization of this mechanism in other plants may provide a possible avenue for the genetic engineering of Se tolerance in plants ideally suited for the phytoremediation of Se contaminated land. Here, we describe the overexpression of a selenocysteine methyltransferase from A. bisulcatus to engineer Se-methylselenocysteine metabolism in the Se non-accumulator Arabidopsis thaliana (Thale cress).

266 citations

Journal ArticleDOI
TL;DR: Using X-ray absorption spectroscopy (XAS) and XAS imaging, the distribution of arsenic species in vivo is revealed and may prove useful for phytoremediating arsenic-contaminated sites, and the strengths of XAS Imaging for distinguishing highly localized species are demonstrated.
Abstract: The fern Pteris vittata accumulates unusually high levels of arsenic. Using X-ray absorption spectroscopy (XAS) and XAS imaging, we reveal the distribution of arsenic species in vivo. Arsenate is transported through the vascular tissue from the roots to the fronds (leaves), where it is reduced to arsenite and stored at high concentrations. Arsenic-thiolate species surrounding veins may be intermediates in this reduction. In gametophytes, arsenite is compartmentalized within the cell vacuole. Arsenic is excluded from cell walls, rhizoids, and reproductive areas. This study provides important insights into arsenic hyperaccumulation, which may prove useful for phytoremediating arsenic-contaminated sites, and demonstrates the strengths of XAS imaging for distinguishing highly localized species.

203 citations

Journal ArticleDOI
TL;DR: The lack of isotopic discrimination in oat plants suggests that Cu uptake and translocation are not redox selective, and the presence of isotopically light Cu in tomatoes is attributed to a reductive uptake mechanism, andThe isotopic shifts within various tissues are attributed to redox cycling during translocation.
Abstract: The fractionation of stable copper (Cu) isotopes during uptake into plant roots and translocation to shoots can provide information on Cu acquisition mechanisms. Isotope fractionation ((65) Cu/(63) Cu) and intact tissue speciation techniques (X-ray absorption spectroscopy, XAS) were used to examine the uptake, translocation and speciation of Cu in strategy I (tomato-Solanum lycopersicum) and strategy II (oat-Avena sativa) plant species. Plants were grown in controlled solution cultures, under varied iron (Fe) conditions, to test whether the stimulation of Fe-acquiring mechanisms can affect Cu uptake in plants. Isotopically light Cu was preferentially incorporated into tomatoes (Δ(65) Cu(whole plant-solution ) = c. -1‰), whereas oats showed minimal isotopic fractionation, with no effect of Fe supply in either species. The heavier isotope was preferentially translocated to shoots in tomato, whereas oat plants showed no significant fractionation during translocation. The majority of Cu in the roots and leaves of both species existed as sulfur-coordinated Cu(I) species resembling glutathione/cysteine-rich proteins. The presence of isotopically light Cu in tomatoes is attributed to a reductive uptake mechanism, and the isotopic shifts within various tissues are attributed to redox cycling during translocation. The lack of isotopic discrimination in oat plants suggests that Cu uptake and translocation are not redox selective.

127 citations


Cited by
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01 Jan 2010
TL;DR: In this paper, the authors describe a scenario where a group of people are attempting to find a solution to the problem of "finding the needle in a haystack" in the environment.
Abstract: 中枢神経系疾患の治療は正常細胞(ニューロン)の機能維持を目的とするが,脳血管障害のように機能障害の原因が細胞の死滅に基づくことは多い.一方,脳腫瘍の治療においては薬物療法や放射線療法といった腫瘍細胞の死滅を目標とするものが大きな位置を占める.いずれの場合にも,細胞死の機序を理解することは各種病態や治療法の理解のうえで重要である.現在のところ最も研究の進んでいる細胞死の型はアポトーシスである.そのなかで重要な位置を占めるミトコンドリアにおける反応および抗アポトーシス因子について概要を紹介する.

2,716 citations

Journal ArticleDOI
TL;DR: The Hg(II) Detector simplifies the experimental setup by enabling a single amplifier to be switched between the Oligonucleotide-Based and DNAzyme-Based detectors.
Abstract: 9.2. Protein-Based Hg(II) Detectors 3467 9.3. Oligonucleotide-Based Hg(II) Detector 3467 9.4. DNAzyme-Based Hg(II) Detectors 3469 9.5. Antibody-Based Hg(II) Detector 3469 10. Mercury Detectors Based on Materials 3469 10.1. Soluble and Fluorescent Polymers 3469 10.2. Membranes, Films, and Fibers 3471 10.3. Micelles 3473 10.4. Nanoparticles 3473 11. Perspectives 3474 12. Addendum 3475 12.1. Small Molecules 3475 12.2. Biomolecules 3477 12.3. Materials 3477 13. List of Abbreviations 3477 14. Acknowledgments 3478 15. References 3478

2,139 citations

Journal ArticleDOI
TL;DR: This review covers the toxicology of mercury and its compounds and leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an “element of mystery.”
Abstract: This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."

1,953 citations

Journal ArticleDOI
TL;DR: The discovery that there is a close relationship between ascorbate and glutathione dates from soon after the characterization of the chemical formulae of the two molecules.
Abstract: The discovery that there is a close relationship between ascorbate and glutathione dates from soon after the characterization of the chemical formulae of the two molecules ([Szent-Gyorgyi, 1931][1]; [Hopkins and Morgan, 1936][2]). Similarly, it has long been known that thylakoids can generate

1,929 citations

Journal ArticleDOI
TL;DR: Recently, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs as mentioned in this paper.
Abstract: The platinum drugs, cisplatin, carboplatin, and oxaliplatin, prevail in the treatment of cancer, but new platinum agents have been very slow to enter the clinic. Recently, however, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs. The use of nanodelivery devices has also grown, and many different strategies have been explored to incorporate platinum warheads into nanomedicine constructs. In this Review, we discuss these efforts to create the next generation of platinum anticancer drugs. The introduction provides the reader with a brief overview of the use, development, and mechanism of action of the approved platinum drugs to provide the context in which more recent research has flourished. We then describe approaches that explore nonclassical platinum(II) complexes with trans geometry or with a monofunctional coordination mode, polynuclea...

1,682 citations