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Singh A, Mandal S, Carey AM, Liu M, Chen S, Seo DK, Yan H, Woodbury N. Interfacing Photosystem I Reaction Centers with a Porous Antimony-Doped Tin Oxide Electrode to Perform Light Driven Redox Chemistry. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.2387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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2
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Punshon T, Carey AM, Ricachenevsky FK, Meharg AA. Elemental distribution in developing rice grains and the effect of flag-leaf arsenate exposure. Environ Exp Bot 2018; 149:51-58. [PMID: 30100643 PMCID: PMC6085101 DOI: 10.1016/j.envexpbot.2018.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We measured the bulk grain concentrations of arsenic (As), along with rubidium (Rb) and strontium (Sr) as indicators of phloem and xylem transport respectively, in rice (Oryza sativa cv. Italica Carolina) pulsed with arsenate at two exposure levels for 5 day periods at progressively later stages of grain fill, between anthesis and maturity, through the cut flag leaf. We compared these to unexposed (negative) controls and positive controls; pulsed with dimethylarsinic acid (DMA). We collected elemental maps of As and micronutrient elements (Fe, Zn, Mn, Cu and Ni) from developing grains of rice. Exposures were either 25 or 100 μg/ml arsenate (As(V)) at various stages of grain development, compared to 25 μg/ml dimethylarsinic acid (DMA); the most efficiently transported As species identified in rice. We used the spatial distribution of arsenic in the grain to infer the presence of As transporters. By exposing grains through the flag leaf rather than via the roots, we were able to measure arsenic transport into the grain during filling under controlled conditions. Exposure to 100 μg/ml As(V) resulted in widespread As localization in both embryo and endosperm, especially in grains exposed to As at later stages of panicle development. This suggests loss of selective transport, likely to be the result of As toxicity. At 25 μg/ml As(V), As colocalized with Mn in the ovular vascular trace (OVT). Exposure to either As(V) or DMA reduced grain Fe, an effect more pronounced when exposure occurred earlier in grain development. The abundance of Cu and Zn were also reduced by As. Arsenic exposure later in grain development caused higher grain As concentrations, indicating the existence of As transporters whose efficiency increases during grain fill. We conclude that localization of As in the grain is a product of both As species and exposure concentration, and that high As(V) translocation from the flag leaf can result in high As concentrations in the endosperm.
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Affiliation(s)
- Tracy Punshon
- Dartmouth College, Department of Biological Sciences, Life Sciences Center, 78 College Street, Hanover, NH 03755, USA
- Correspondence: ; Tel.: +1-603-646-1037; Fax: +1-603-646-1347
| | - Anne-Marie Carey
- Center for Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Felipe Klein Ricachenevsky
- Programa de Pós-Graduação em Agrobiologia, Departamento de Biologia, Universidade Federal de Santa Maria, Av. Roraima 1000, 97105-900, Santa Maria, RS, Brazil
- Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Andrew A. Meharg
- Institute for Global Food Security, Queen’s University Belfast, David Keir Building, Strandmillis Road, Belfast BT9 5BN, UK
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Southall J, Henry SL, Gardiner AT, Roszak AW, Mullen W, Carey AM, Kelly SM, de Percin Northumberland CO, Cogdell RJ. Characterisation of a pucBA deletion mutant from Rhodopseudomonas palustris lacking all but the pucBA d genes. Photosynth Res 2018; 135:9-21. [PMID: 28567613 PMCID: PMC5783997 DOI: 10.1007/s11120-017-0386-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/08/2017] [Indexed: 06/01/2023]
Abstract
Rhodopseudomonas palustris is a species of purple photosynthetic bacteria that has a multigene family of puc genes that encode the alpha and beta apoproteins, which form the LH2 complexes. A genetic dissection strategy has been adopted in order to try and understand which spectroscopic form of LH2 these different genes produce. This paper presents a characterisation of one of the deletion mutants generated in this program, the pucBAd only mutant. This mutant produces an unusual spectroscopic form of LH2 that only has a single large NIR absorption band at 800 nm. Spectroscopic and pigment analyses on this complex suggest that it has basically a similar overall structure as that of the wild-type HL LH2 complex. The mutant has the unique phenotype where the mutant LH2 complex is only produced when cells are grown at LL. At HL the mutant only produces the LH1-RC core complex.
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Affiliation(s)
- June Southall
- Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK.
| | - Sarah L Henry
- Biomedical Engineering, School of Engineering, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Alastair T Gardiner
- Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Aleksander W Roszak
- Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - William Mullen
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Anne-Marie Carey
- Center for Innovations in Medicine, The Biodesign Institute, Arizona State University, 1001 S. McAllister Ave., Tempe, AZ, 85287-5001, USA
| | - Sharon M Kelly
- Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | | | - Richard J Cogdell
- Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
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Carey AM, Zhang H, Liu M, Sharaf D, Akram N, Yan H, Lin S, Woodbury NW, Seo DK. Enhancing Photocurrent Generation in Photosynthetic Reaction Center-Based Photoelectrochemical Cells with Biomimetic DNA Antenna. ChemSusChem 2017; 10:4457-4460. [PMID: 28929590 DOI: 10.1002/cssc.201701390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 09/18/2017] [Indexed: 06/07/2023]
Abstract
Three- to four-times higher performance of biohybrid photoelectrochemical cells with photosynthetic reaction centers (RC) has been achieved by using a DNA-based biomimetic antenna. Synthetic dyes Cy3 and Cy5 were chosen and strategically placed in the anntena in such a way that they can collect additional light energy in the visible region of the solar spectrum and transfer it to RC through Förster resonance energy transfer (FRET). The antenna, a DNA templated multiple dye system, is attached to each Rhodobacter sphaeroides RC near the primary donor, P, to facilitate the energy transfer process. Excitation with a broad light spectrum (approximating sunlight) triggers a cascade of excitation energy transfer from Cy3 to Cy5 to P, and also directly from Cy5 to P. This additional excitation energy increases the RC absorbance cross-section in the visible and thus the performance of the photoelectrochemical cells. DNA-based biomimetic antennas offer a tunable, modular light-harvesting system for enhancing RC solar coverage and performance for photoelectrochemical cells.
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Affiliation(s)
- Anne-Marie Carey
- Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - HaoJie Zhang
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Minghui Liu
- Molecular Design and Biomimetics, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Daiana Sharaf
- Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Natalie Akram
- Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Hao Yan
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Molecular Design and Biomimetics, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Su Lin
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Neal W Woodbury
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Innovation in Medicine, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Dong-Kyun Seo
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
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Mandal S, Carey AM, Locsin J, Gao BR, Williams JC, Allen JP, Lin S, Woodbury NW. Mechanism of Triplet Energy Transfer in Photosynthetic Bacterial Reaction Centers. J Phys Chem B 2017; 121:6499-6510. [DOI: 10.1021/acs.jpcb.7b03373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sarthak Mandal
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | - Anne-Marie Carey
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | - Joshua Locsin
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | | | - JoAnn C. Williams
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - James P. Allen
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - Su Lin
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - Neal W. Woodbury
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
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Carey AM, Zhang H, Mieritz D, Volosin A, Gardiner AT, Cogdell RJ, Yan H, Seo DK, Lin S, Woodbury NW. Photocurrent Generation by Photosynthetic Purple Bacterial Reaction Centers Interfaced with a Porous Antimony-Doped Tin Oxide (ATO) Electrode. ACS Appl Mater Interfaces 2016; 8:25104-25110. [PMID: 27576015 DOI: 10.1021/acsami.6b07940] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ability to exchange energy and information between biological and electronic materials is critical in the development of hybrid electronic systems in biomedicine, environmental sensing, and energy applications. While sensor technology has been extensively developed to collect detailed molecular information, less work has been done on systems that can specifically modulate the chemistry of the environment with temporal and spatial control. The bacterial photosynthetic reaction center represents an ideal photonic component of such a system in that it is capable of modifying local chemistry via light-driven redox reactions with quantitative control over reaction rates and has inherent spectroscopic probes for monitoring function. Here a well-characterized model system is presented, consisting of a transparent, porous electrode (antimony-doped tin oxide) which is electrochemically coupled to the reaction center via a cytochrome c molecule. Upon illumination, the reaction center performs the 2-step, 2-electron reduction of a ubiquinone derivative which exchanges with oxidized quinone in solution. Electrons from the electrode then move through the cytochrome to reoxidize the reaction center electron donor. The result is a facile platform for performing redox chemistry that can be optically and electronically controlled in time and space.
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Affiliation(s)
- Anne-Marie Carey
- Biodesign Center for Innovation in Medicine at Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States
| | - HaoJie Zhang
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Daniel Mieritz
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Alex Volosin
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Alastair T Gardiner
- Institute of Molecular Cell and Systems Biology, University of Glasgow , Glasgow, Scotland G12 8QQ, United Kingdom
| | - Richard J Cogdell
- Institute of Molecular Cell and Systems Biology, University of Glasgow , Glasgow, Scotland G12 8QQ, United Kingdom
| | - Hao Yan
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
- Biodesign Center for Molecular Design and Biomimetics at Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States
| | - Dong-Kyun Seo
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Su Lin
- Biodesign Center for Innovation in Medicine at Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Neal W Woodbury
- Biodesign Center for Innovation in Medicine at Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
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Sun C, Carey AM, Gao BR, Wraight CA, Woodbury NW, Lin S. Ultrafast Electron Transfer Kinetics in the LM Dimer of Bacterial Photosynthetic Reaction Center from Rhodobacter sphaeroides. J Phys Chem B 2016; 120:5395-404. [PMID: 27243380 DOI: 10.1021/acs.jpcb.6b05082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
It has become increasingly clear that dynamics plays a major role in the function of many protein systems. One system that has proven particularly facile for studying the effects of dynamics on protein-mediated chemistry is the bacterial photosynthetic reaction center from Rhodobacter sphaeroides. Previous experimental and computational analysis have suggested that the dynamics of the protein matrix surrounding the primary quinone acceptor, QA, may be particularly important in electron transfer involving this cofactor. One can substantially increase the flexibility of this region by removing one of the reaction center subunits, the H-subunit. Even with this large change in structure, photoinduced electron transfer to the quinone still takes place. To evaluate the effect of H-subunit removal on electron transfer to QA, we have compared the kinetics of electron transfer and associated spectral evolution for the LM dimer with that of the intact reaction center complex on picosecond to millisecond time scales. The transient absorption spectra associated with all measured electron transfer reactions are similar, with the exception of a broadening in the QX transition and a blue-shift in the QY transition bands of the special pair of bacteriochlorophylls (P) in the LM dimer. The kinetics of the electron transfer reactions not involving quinones are unaffected. There is, however, a 4-fold decrease in the electron transfer rate from the reduced bacteriopheophytin to QA in the LM dimer compared to the intact reaction center and a similar decrease in the recombination rate of the resulting charge-separated state (P(+)QA(-)). These results are consistent with the concept that the removal of the H-subunit results in increased flexibility in the region around the quinone and an associated shift in the reorganization energy associated with charge separation and recombination.
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Affiliation(s)
- Chang Sun
- Department of Biochemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | | | - Bing-Rong Gao
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , Jilin, China 130012
| | - Colin A Wraight
- Department of Biochemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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Maiuri M, Réhault J, Carey AM, Hacking K, Garavelli M, Lüer L, Polli D, Cogdell RJ, Cerullo G. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium. J Chem Phys 2016; 142:212433. [PMID: 26049453 DOI: 10.1063/1.4919056] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Qx and Qy transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S2 of the Spx towards the Qx state of the B890, and (iii) the internal conversion from Qx to Qy within the B890.
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Affiliation(s)
- Margherita Maiuri
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133, Italy
| | - Julien Réhault
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133, Italy
| | - Anne-Marie Carey
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland, United Kingdom
| | - Kirsty Hacking
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland, United Kingdom
| | - Marco Garavelli
- Dipartimento di Chimica "G. Ciamician," Università di Bologna, Via Selmi 2, IT-40126 Bologna, Italy
| | - Larry Lüer
- Madrid Institute for Advanced Studies, IMDEA Nanociencia, Madrid, Spain
| | - Dario Polli
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133, Italy
| | - Richard J Cogdell
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland, United Kingdom
| | - Giulio Cerullo
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133, Italy
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Lüer L, Carey AM, Henry S, Maiuri M, Hacking K, Polli D, Cerullo G, Cogdell RJ. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes. Biophys J 2015; 109:1885-98. [PMID: 26536265 DOI: 10.1016/j.bpj.2015.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/16/2015] [Accepted: 09/08/2015] [Indexed: 11/24/2022] Open
Abstract
Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.
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Affiliation(s)
- Larry Lüer
- Madrid Institute for Advanced Studies, IMDEA Nanociencia, Madrid, Spain.
| | - Anne-Marie Carey
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, Glasgow, Scotland; Biodesign Institute, Arizona State University, Tempe, Arizona
| | - Sarah Henry
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, Glasgow, Scotland; Biodesign Institute, Arizona State University, Tempe, Arizona
| | - Margherita Maiuri
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, Milano, Italy; Department of Chemistry, Princeton University, Princeton, New Jersey
| | - Kirsty Hacking
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, Glasgow, Scotland
| | - Dario Polli
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, Milano, Italy
| | - Giulio Cerullo
- CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, Milano, Italy
| | - Richard J Cogdell
- Glasgow Biomedical Research Centre, IBLS, University of Glasgow, Glasgow, Scotland
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Löhner A, Carey AM, Hacking K, Picken N, Kelly S, Cogdell R, Köhler J. The origin of the split B800 absorption peak in the LH2 complexes from Allochromatium vinosum. Photosynth Res 2015; 123:23-31. [PMID: 25150556 DOI: 10.1007/s11120-014-0036-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 08/12/2014] [Indexed: 06/03/2023]
Abstract
The absorption spectrum of the high-light peripheral light-harvesting (LH) complex from the photosynthetic purple bacterium Allochromatium vinosum features two strong absorptions around 800 and 850 nm. For the LH2 complexes from the species Rhodopseudomonas acidophila and Rhodospirillum molischianum, where high-resolution X-ray structures are available, similar bands have been observed and were assigned to two pigment pools of BChl a molecules that are arranged in two concentric rings (B800 and B850) with nine (acidophila) or eight (molischianum) repeat units, respectively. However, for the high-light peripheral LH complex from Alc. vinosum, the intruiging feature is that the B800 band is split into two components. We have studied this pigment-protein complex by ensemble CD spectroscopy and polarisation-resolved single-molecule spectroscopy. Assuming that the high-light peripheral LH complex in Alc. vinosum is constructed on the same modular principle as described for LH2 from Rps. acidophila and Rsp. molischianum, we used those repeat units as a starting point for simulating the spectra. We find the best agreement between simulation and experiment for a ring-like oligomer of 12 repeat units, where the mutual arrangement of the B800 and B850 rings resembles those from Rsp. molischianum. The splitting of the B800 band can be reproduced if both an excitonic coupling between dimers of B800 molecules and their interaction with the B850 manifold are taken into account. Such dimers predict an interesting apoprotein organisation as discussed below.
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Affiliation(s)
- Alexander Löhner
- Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Bayreuth, Germany
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Magdaong N, LaFountain AM, Greco JA, Gardiner AT, Carey AM, Cogdell RJ, Gibson GN, Birge RR, Frank HA. High efficiency light harvesting by carotenoids in the LH2 complex from photosynthetic bacteria: unique adaptation to growth under low-light conditions. J Phys Chem B 2014; 118:11172-89. [PMID: 25171303 PMCID: PMC4174993 DOI: 10.1021/jp5070984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/26/2014] [Indexed: 12/03/2022]
Abstract
Rhodopin, rhodopinal, and their glucoside derivatives are carotenoids that accumulate in different amounts in the photosynthetic bacterium, Rhodoblastus (Rbl.) acidophilus strain 7050, depending on the intensity of the light under which the organism is grown. The different growth conditions also have a profound effect on the spectra of the bacteriochlorophyll (BChl) pigments that assemble in the major LH2 light-harvesting pigment-protein complex. Under high-light conditions the well-characterized B800-850 LH2 complex is formed and accumulates rhodopin and rhodopin glucoside as the primary carotenoids. Under low-light conditions, a variant LH2, denoted B800-820, is formed, and rhodopinal and rhodopinal glucoside are the most abundant carotenoids. The present investigation compares and contrasts the spectral properties and dynamics of the excited states of rhodopin and rhodopinal in solution. In addition, the systematic differences in pigment composition and structure of the chromophores in the LH2 complexes provide an opportunity to explore the effect of these factors on the rate and efficiency of carotenoid-to-BChl energy transfer. It is found that the enzymatic conversion of rhodopin to rhodopinal by Rbl. acidophilus 7050 grown under low-light conditions results in nearly 100% carotenoid-to-BChl energy transfer efficiency in the LH2 complex. This comparative analysis provides insight into how photosynthetic systems are able to adapt and survive under challenging environmental conditions.
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Affiliation(s)
- Nikki
M. Magdaong
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Amy M. LaFountain
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Jordan A. Greco
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Alastair T. Gardiner
- Institute
of Molecular Cell and Systems Biology, University
of Glasgow, Glasgow G12 8TA, Scotland
| | - Anne-Marie Carey
- Institute
of Molecular Cell and Systems Biology, University
of Glasgow, Glasgow G12 8TA, Scotland
| | - Richard J. Cogdell
- Institute
of Molecular Cell and Systems Biology, University
of Glasgow, Glasgow G12 8TA, Scotland
| | - George N. Gibson
- Department
of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Robert R. Birge
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Harry A. Frank
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
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12
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Carey AM, Hacking K, Picken N, Honkanen S, Kelly S, Niedzwiedzki DM, Blankenship RE, Shimizu Y, Wang-Otomo ZY, Cogdell RJ. Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum. Biochim Biophys Acta 2014; 1837:1849-1860. [PMID: 25111749 DOI: 10.1016/j.bbabio.2014.07.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/25/2014] [Accepted: 07/29/2014] [Indexed: 10/24/2022]
Abstract
This study systematically investigated the different types of LH2 produced by Allochromatium (Alc.) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and B800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both α and β polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila.
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Affiliation(s)
- Anne-Marie Carey
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK.
| | - Kirsty Hacking
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Nichola Picken
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Suvi Honkanen
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Sharon Kelly
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | | | - Robert E Blankenship
- Photosynthetic Antenna Research Center, Washington University, St. Louis, MO 63130, USA; Department of Biology, Washington University, St. Louis, MO 63130, USA; Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Yuuki Shimizu
- Faculty of Science, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512, Japan
| | | | - Richard J Cogdell
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
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Edwards A, Hicks F, Winterburn K, McTague L, Carey AM. AN INNOVATIVE DEVELOPMENT APPROACH FOR ACUTE HOSPITAL SENIOR CLINICIANS TO IMPLEMENT THE NATIONAL EOLC STRATEGY 2008. BMJ Support Palliat Care 2014. [DOI: 10.1136/bmjspcare-2014-000654.221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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14
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Norton GJ, Adomako EE, Deacon CM, Carey AM, Price AH, Meharg AA. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species. Environ Pollut 2013; 177:38-47. [PMID: 23466730 DOI: 10.1016/j.envpol.2013.01.049] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/31/2013] [Accepted: 01/31/2013] [Indexed: 05/02/2023]
Abstract
Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic.
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Affiliation(s)
- Gareth J Norton
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen AB24 3UU, UK.
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Hauer J, Maiuri M, Viola D, Lukes V, Henry S, Carey AM, Cogdell RJ, Cerullo G, Polli D. Explaining the temperature dependence of spirilloxanthin's S* signal by an inhomogeneous ground state model. J Phys Chem A 2013; 117:6303-10. [PMID: 23577754 PMCID: PMC3725610 DOI: 10.1021/jp4011372] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We
investigate the nature of the S* excited state in carotenoids by performing
a series of pump–probe experiments with sub-20 fs time resolution
on spirilloxanthin in a polymethyl-methacrylate matrix varying the
sample temperature. Following photoexcitation, we observe sub-200
fs internal conversion of the bright S2 state into the
lower-lying S1 and S* states, which in turn relax to the
ground state on a picosecond time scale. Upon cooling down the sample
to 77 K, we observe a systematic decrease of the S*/S1 ratio.
This result can be explained by assuming two thermally populated ground
state isomers. The higher lying one generates the S* state, which
can then be effectively frozen out by cooling. These findings are
supported by quantum chemical modeling and provide strong evidence
for the existence and importance of ground state isomers in the photophysics
of carotenoids.
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Affiliation(s)
- J Hauer
- Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, 1040 Vienna, Austria
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16
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Carey AM, Scheckel KG, Lombi E, Newville M, Choi Y, Norton GJ, Price AH, Meharg AA. Grain accumulation of selenium species in rice (Oryza sativa L.). Environ Sci Technol 2012; 46:5557-64. [PMID: 22502742 DOI: 10.1021/es203871j] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a ± stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.
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Affiliation(s)
- Anne-Marie Carey
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen AB24 3UU, United Kingdom
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Carey AM, Norton GJ, Deacon C, Scheckel KG, Lombi E, Punshon T, Guerinot ML, Lanzirotti A, Newville M, Choi Y, Price AH, Meharg AA. Phloem transport of arsenic species from flag leaf to grain during grain filling. New Phytol 2011. [PMID: 21658183 DOI: 10.1111/j.1469-8137.2011.03789.x/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
• Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. • Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. • Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. • These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.
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Affiliation(s)
- Anne-Marie Carey
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Gareth J Norton
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Claire Deacon
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Kirk G Scheckel
- National Risk Management Research Laboratory, US Environmental Protection Agency, 5995 Centre Hill Avenue, Cincinnati, OH 45224, USA
| | - Enzo Lombi
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, S. Australia, SA-5095 Australia
| | - Tracy Punshon
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Mary Lou Guerinot
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Antonio Lanzirotti
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Matt Newville
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Yongseong Choi
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Adam H Price
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Andrew A Meharg
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
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Carey AM, Norton GJ, Deacon C, Scheckel KG, Lombi E, Punshon T, Guerinot ML, Lanzirotti A, Newville M, Choi Y, Price AH, Meharg AA. Phloem transport of arsenic species from flag leaf to grain during grain filling. New Phytol 2011; 192:87-98. [PMID: 21658183 PMCID: PMC3932528 DOI: 10.1111/j.1469-8137.2011.03789.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
• Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. • Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. • Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. • These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.
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Affiliation(s)
- Anne-Marie Carey
- Institute of Biological and Environmental Sciences, University of
Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Gareth J. Norton
- Institute of Biological and Environmental Sciences, University of
Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Claire Deacon
- Institute of Biological and Environmental Sciences, University of
Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Kirk G. Scheckel
- National Risk Management Research Laboratory, US Environmental
Protection Agency, 5995 Centre Hill Avenue, Cincinnati, Ohio 45224, USA
| | - Enzo Lombi
- Centre for Environmental Risk Assessment and Remediation, University
of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, S. Australia,
SA-5095 Australia
| | - Tracy Punshon
- Department of Biological Sciences, Dartmouth College, Hanover, NH
03755, USA
| | - Mary Lou Guerinot
- Department of Biological Sciences, Dartmouth College, Hanover, NH
03755, USA
| | - Antonio Lanzirotti
- Centre for Advanced Radiation Sources, the University of Chicago,
Chicago, IL 60637, USA
| | - Matt Newville
- Centre for Advanced Radiation Sources, the University of Chicago,
Chicago, IL 60637, USA
| | - Yongseong Choi
- Centre for Advanced Radiation Sources, the University of Chicago,
Chicago, IL 60637, USA
| | - Adam H. Price
- Institute of Biological and Environmental Sciences, University of
Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Andrew A. Meharg
- Institute of Biological and Environmental Sciences, University of
Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
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19
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Carey AM, Norton GJ, Deacon C, Scheckel KG, Lombi E, Punshon T, Guerinot ML, Lanzirotti A, Newville M, Choi Y, Price AH, Meharg AA. Phloem transport of arsenic species from flag leaf to grain during grain filling. New Phytol 2011. [PMID: 21658183 DOI: 10.1111/j.1469-8137.2011.03789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
• Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. • Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. • Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. • These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.
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Affiliation(s)
- Anne-Marie Carey
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Gareth J Norton
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Claire Deacon
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Kirk G Scheckel
- National Risk Management Research Laboratory, US Environmental Protection Agency, 5995 Centre Hill Avenue, Cincinnati, OH 45224, USA
| | - Enzo Lombi
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, S. Australia, SA-5095 Australia
| | - Tracy Punshon
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Mary Lou Guerinot
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Antonio Lanzirotti
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Matt Newville
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Yongseong Choi
- Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA
| | - Adam H Price
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
| | - Andrew A Meharg
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK
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Dawson JJC, Tetzlaff D, Carey AM, Raab A, Soulsby C, Killham K, Meharg AA. Characterizing Pb mobilization from upland soils to streams using (206)Pb/(207)Pb isotopic ratios. Environ Sci Technol 2010; 44:243-249. [PMID: 19954181 DOI: 10.1021/es902664d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Anthropogenically deposited lead (Pb) binds efficiently to soil organic matter, which can be mobilized through hydrologically mediated mechanisms, with implications for ecological and potable quality of receiving waters. Lead isotopic ((206)Pb/(207)Pb) ratios change down peat profiles as a consequence of long-term temporal variation in depositional sources, each with distinctive isotopic signatures. This study characterizes differential Pb transport mechanisms from deposition to streams at two small catchments with contrasting soil types in upland Wales, U.K., by determining Pb concentrations and (206)Pb/(207)Pb ratios from soil core profiles, interstitial pore waters, and stream water. Hydrological characteristics of soils are instrumental in determining the location in soil profiles of exported Pb and hence concentration and (206)Pb/(207)Pb ratios in surface waters. The highest Pb concentrations from near-surface soils are mobilized, concomitant with high dissolved organic carbon (DOC) exports, from hydrologically responsive peat soils with preferential shallow subsurface flows, leading to increased Pb concentrations in stream water and isotopic signatures more closely resembling recently deposited Pb. In more minerogenic soils, percolation of water allows Pb, bound to DOC, to be retained in mineral horizons and combined with other groundwater sources, resulting in Pb being transported from throughout the profile with a more geogenic isotopic signature. This study shows that (206)Pb/(207)Pb ratios can enhance our understanding of the provenances and transport mechanisms of Pb and potentially organic matter within upland soils.
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Affiliation(s)
- Julian J C Dawson
- Northern Rivers Institute, School of Geosciences, University of Aberdeen, St. Mary's Building, Elphinstone Road, Aberdeen AB24 3UF, U.K.
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Carey AM, Scheckel KG, Lombi E, Newville M, Choi Y, Norton GJ, Charnock JM, Feldmann J, Price AH, Meharg AA. Grain unloading of arsenic species in rice. Plant Physiol 2010; 152:309-19. [PMID: 19880610 PMCID: PMC2799365 DOI: 10.1104/pp.109.146126] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/29/2009] [Indexed: 05/18/2023]
Abstract
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 +/- 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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Williams PN, Lombi E, Sun GX, Scheckel K, Zhu YG, Feng X, Zhu J, Carey AM, Adomako E, Lawgali Y, Deacon C, Meharg AA. Selenium characterization in the global rice supply chain. Environ Sci Technol 2009; 43:6024-30. [PMID: 19731713 DOI: 10.1021/es900671m] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
For up to 1 billion people worldwide, insufficient dietary intake of selenium (Se) is a serious health constraint. Cereals are the dominant Se source for those on low protein diets, as typified by the global malnourished population. With crop Se content constrained largely by underlying geology, regional soil Se variations are often mirrored by their locally grown staples. Despite this, the Se concentrations of much of the world's rice, the mainstay of so many, is poorly characterized, for both total Se content and Se speciation. In this study, 1092 samples of market sourced polished rice were obtained. The sampled rice encompassed dominant rice producing and exporting countries. Rice from the U.S. and India were found to be the most enriched, while mean average levels were lowest in Egyptian rice: approximately 32-fold less than their North American equivalents. By weighting country averages by contribution to either global production or export, modeled baseline values for both were produced. Based on a daily rice consumption of 300 g day(-1), around 75% of the grains from the production and export pools would fail to provide 70% of daily recommended Se intakes. Furthermore, Se localization and speciation characterization using X-ray fluorescence (micro-XRF) and X-ray absorption near edge structure (micro-XANES) techniques were investigated in a Se-rich sample. The results revealed that the large majority of Se in the endosperm was present in organic forms.
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Affiliation(s)
- Paul N Williams
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Sun GX, Williams PN, Zhu YG, Deacon C, Carey AM, Raab A, Feldmann J, Meharg AA. Survey of arsenic and its speciation in rice products such as breakfast cereals, rice crackers and Japanese rice condiments. Environ Int 2009; 35:473-475. [PMID: 18775567 DOI: 10.1016/j.envint.2008.07.020] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Rice has been demonstrated to be one of the major contributors to arsenic (As) in human diets in addition to drinking water, but little is known about rice products as an additional source of As exposure. Rice products were analyzed for total As and a subset of samples were measured for arsenic speciation using high performance liquid chromatography interfaced with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A wide range of rice products had total and inorganic arsenic levels that typified those found in rice grain including, crisped rice, puffed rice, rice crackers, rice noodles and a range of Japanese rice condiments as well as rice products targeted at the macrobiotic, vegan, lactose intolerant and gluten intolerance food market. Most As in rice products are inorganic As (75.2-90.1%). This study provides a wider appreciation of how inorganic arsenic derived from rice products enters the human diet.
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Affiliation(s)
- Guo-Xin Sun
- Research Center for Eco-Environmental Sciences, the Chinese Academy of Sciences, Beijing 100085, China
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Lombi E, Scheckel KG, Pallon J, Carey AM, Zhu YG, Meharg AA. Speciation and distribution of arsenic and localization of nutrients in rice grains. New Phytol 2009. [PMID: 19549132 DOI: 10.1111/j.1469-8137.2009.02912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (micro-XANES, micro-X-ray fluorescence (micro-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.
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Affiliation(s)
- E Lombi
- Department of Agriculture and Ecology, Faculty of Life Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
- Present address: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, South Australia, SA-5095 Australia and CRC CARE, PO Box 486, Salisbury, South Australia 5106, Australia
| | - K G Scheckel
- National Risk Management Research Laboratory, US Environmental Protection Agency, 5995 Centre Hill Avenue, Cincinnati, Ohio 45224, USA
| | - J Pallon
- Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, PO Box 118, SE-221, Sweden
| | - A M Carey
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Boulevard, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Y G Zhu
- Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - A A Meharg
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Boulevard, St Machar Drive, Aberdeen, AB24 3UU, UK
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Lombi E, Scheckel KG, Pallon J, Carey AM, Zhu YG, Meharg AA. Speciation and distribution of arsenic and localization of nutrients in rice grains. New Phytol 2009; 184:193-201. [PMID: 19549132 DOI: 10.1111/j.1469-8137.2009.02912.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (micro-XANES, micro-X-ray fluorescence (micro-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.
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Affiliation(s)
- E Lombi
- Department of Agriculture and Ecology, Faculty of Life Science, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
- Present address: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, South Australia, SA-5095 Australia and CRC CARE, PO Box 486, Salisbury, South Australia 5106, Australia
| | - K G Scheckel
- National Risk Management Research Laboratory, US Environmental Protection Agency, 5995 Centre Hill Avenue, Cincinnati, Ohio 45224, USA
| | - J Pallon
- Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, PO Box 118, SE-221, Sweden
| | - A M Carey
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Boulevard, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Y G Zhu
- Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - A A Meharg
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Boulevard, St Machar Drive, Aberdeen, AB24 3UU, UK
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Sun GX, Williams PN, Carey AM, Zhu YG, Deacon C, Raab A, Feldmann J, Islam RM, Meharg AA. Inorganic arsenic in rice bran and its products are an order of magnitude higher than in bulk grain. Environ Sci Technol 2008. [PMID: 18939599 DOI: 10.1021/es801238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Rice is more elevated in arsenic than all other grain crops tested to date, with whole grain (brown) rice having higher arsenic levels than polished (white). It is reported here that rice bran, both commercially purchased and specifically milled for this study, have levels of inorganic arsenic, a nonthreshold, class 1 carcinogen, reaching concentrations of approximately 1 mg/kg dry weight, around 10-20 fold higher than concentrations found in bulk grain. Although pure rice bran is used as a health food supplement, perhaps of more concern is rice bran solubles, which are marketed as a superfood and as a supplement to malnourished children in international aid programs. Five rice bran solubles products were tested, sourced from the United States and Japan, and were found to have 0.61-1.9 mg/kg inorganic arsenic. Manufactures recommend approximately 20 g servings of the rice bran solubles per day, which equates to a 0.012-0.038 mg intake of inorganic arsenic. There are no maximum concentration levels (MCLs) set for arsenic or its species in food stuffs. EU and U.S. water regulations, set at 0.01 mg/L total or inorganic arsenic, respectively, are based on the assumption that 1 L of water per day is consumed, i.e., 0.01 mg of arsenic/ day. At the manufacturers recommended rice bran solubles consumption rate, inorganic arsenic intake exceeds 0.01 mg/ day, remembering that rice bran solubles are targeted at malnourished children and that actual risk is based on mg kg(-1) day(-1) intake.
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Affiliation(s)
- Guo-Xin Sun
- Institute of Biology and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen AB24 3UU, United Kingdom
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Sun GX, Williams PN, Carey AM, Zhu YG, Deacon C, Raab A, Feldmann J, Islam RM, Meharg AA. Inorganic arsenic in rice bran and its products are an order of magnitude higher than in bulk grain. Environ Sci Technol 2008; 42:7542-7546. [PMID: 18939599 DOI: 10.1021/es801238p] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Rice is more elevated in arsenic than all other grain crops tested to date, with whole grain (brown) rice having higher arsenic levels than polished (white). It is reported here that rice bran, both commercially purchased and specifically milled for this study, have levels of inorganic arsenic, a nonthreshold, class 1 carcinogen, reaching concentrations of approximately 1 mg/kg dry weight, around 10-20 fold higher than concentrations found in bulk grain. Although pure rice bran is used as a health food supplement, perhaps of more concern is rice bran solubles, which are marketed as a superfood and as a supplement to malnourished children in international aid programs. Five rice bran solubles products were tested, sourced from the United States and Japan, and were found to have 0.61-1.9 mg/kg inorganic arsenic. Manufactures recommend approximately 20 g servings of the rice bran solubles per day, which equates to a 0.012-0.038 mg intake of inorganic arsenic. There are no maximum concentration levels (MCLs) set for arsenic or its species in food stuffs. EU and U.S. water regulations, set at 0.01 mg/L total or inorganic arsenic, respectively, are based on the assumption that 1 L of water per day is consumed, i.e., 0.01 mg of arsenic/ day. At the manufacturers recommended rice bran solubles consumption rate, inorganic arsenic intake exceeds 0.01 mg/ day, remembering that rice bran solubles are targeted at malnourished children and that actual risk is based on mg kg(-1) day(-1) intake.
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Affiliation(s)
- Guo-Xin Sun
- Institute of Biology and Environmental Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen AB24 3UU, United Kingdom
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Zhu YG, Sun GX, Lei M, Teng M, Liu YX, Chen NC, Wang LH, Carey AM, Deacon C, Raab A, Meharg AA, Williams PN. High percentage inorganic arsenic content of mining impacted and nonimpacted Chinese rice. Environ Sci Technol 2008; 42:5008-13. [PMID: 18678041 DOI: 10.1021/es8001103] [Citation(s) in RCA: 279] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Two approaches were undertaken to characterize the arsenic (As) content of Chinese rice. First, a national market basket survey (n = 240) was conducted in provincial capitals, sourcing grain from China's premier rice production areas. Second, to reflect rural diets, paddy rice (n = 195) directly from farmers fields were collected from three regions in Hunan, a key rice producing province located in southern China. Two of the sites were within mining and smeltery districts, and the third was devoid of large-scale metal processing industries. Arsenic levels were determined in all the samples while a subset (n = 33) were characterized for As species, using a new simple and rapid extraction method suitable for use with Hamilton PRP-X100 anion exchange columns and HPLC-ICP-MS. The vast majority (85%) of the market rice grains possessed total As levels < 150 ng g(-1). The rice collected from mine-impacted regions, however, were found to be highly enriched in As, reaching concentrations of up to 624 ng g(-1). Inorganic As (As(i)) was the predominant species detected in all of the speciated grain, with As(i) levels in some samples exceeding 300 ng g(-1). The As(i) concentration in polished and unpolished Chinese rice was successfully predicted from total As levels. The mean baseline concentrations for As(i) in Chinese market rice based on this survey were estimated to be 96 ng g(-1) while levels in mine-impacted areas were higher with ca. 50% of the rice in one region predicted to fail the national standard.
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Affiliation(s)
- Y G Zhu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Meharg AA, Deacon C, Campbell RCJ, Carey AM, Williams PN, Feldmann J, Raab A. Inorganic arsenic levels in rice milk exceed EU and US drinking water standards. ACTA ACUST UNITED AC 2008; 10:428-31. [DOI: 10.1039/b800981c] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Carey AM, Pramanik R, Nicholson LJ, Dew TK, Martin FL, Muir GH, Morris JDH. Ras-MEK-ERK signaling cascade regulates androgen receptor element-inducible gene transcription and DNA synthesis in prostate cancer cells. Int J Cancer 2007; 121:520-7. [PMID: 17415712 DOI: 10.1002/ijc.22715] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Treatment of prostate cancer (CaP) patients frequently involves androgen ablation, but resistance often develops and androgen-insensitive tumors emerge. The molecular basis for the development of refractory CaP that grows in an androgen-independent manner is poorly understood, but alterations in growth factor signaling pathways are likely to be involved. We examined the growth factor modulation of androgen-receptor element (ARE)-inducible luciferase reporter gene activity and consequent DNA synthesis as a measure of proliferative growth in androgen-dependent LNCaP or androgen-independent PC3 or DU145 CaP cells. The synthetic androgen R1881 stimulated ARE-inducible reporter gene activity and prostate-specific antigen expression in LNCaP cells and the MEK/ERK inhibitor U0126 or the anti-androgen bicalutamide (casodex) prevented both of these responses. Activated V12-Ha-Ras expression in LNCaP cells also stimulated ARE-inducible gene transcription, and U0126 or the farnesyltransferase inhibitor FTI-277 but not bicalutamide blocked this. ARE-inducible reporter gene activity was elevated already in PC3 cells, and ERK was constitutively activated in serum-starved LNCaP or DU145 cells. U0126 inhibited each of these responses and also inhibited DNA synthesis in all 3 CaP cell lines. These results demonstrate that chronic stimulation of the Ras-MEK-ERK signaling pathway can sustain ARE-inducible gene transcription and growth of CaP cells, and suggests that components of this pathway may offer targets for cancer therapy.
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Morris JDH, Pramanik R, Zhang X, Carey AM, Ragavan N, Martin FL, Muir GH. Selenium- or quercetin-induced retardation of DNA synthesis in primary prostate cells occurs in the presence of a concomitant reduction in androgen-receptor activity. Cancer Lett 2005; 239:111-22. [PMID: 16239064 DOI: 10.1016/j.canlet.2005.07.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 07/24/2005] [Accepted: 07/28/2005] [Indexed: 11/28/2022]
Abstract
Prostate cancer (CaP) is the most common male malignancy in the Western world. Selenium or quercetin may down-regulate prostate-cell proliferation in immortalised cells (e.g. androgen-responsive LNCaP cells). However, whether such effects are apparent in primary prostate epithelial cells (PECs) remains to be examined. Following surgical resection, primary PECs isolated from tissues (n=10 patients) were cultured in the presence or absence of selenium, selenomethionine or quercetin. Tissues from a minimum of three patients were used to generate cell preparations that were cultured independently for the purposes of the experimental analysis of each test agent. These agents were also examined in LNCaP cells. DNA synthesis was assessed by the percentage of PECs or LNCaP cells that incorporated 5-bromo-2-deoxyuridine (BrdU) into DNA. All three test agents induced a dose-related reduction in the percentage of PECs or LNCaP cells labelled with BrdU. In LNCaP cells transfected with an androgen-receptor (AR)-reporter gene coupled to luciferase, selenomethionine or quercetin reduced AR activity. Chemoprevention may retard DNA synthesis in short-term primary PECs and expression of AR-inducible elements may be a concomitant factor.
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Affiliation(s)
- Jonathan D H Morris
- King's College London, GKT School of Medicine and Dentistry, Rayne Institute, 123 Coldharbour Lane, London SE5 9NU, UK
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Wilcock A, Manderson C, Weller R, Walker G, Carr D, Carey AM, Broadhurst D, Mew J, Ernst E. Does aromatherapy massage benefit patients with cancer attending a specialist palliative care day centre? Palliat Med 2004; 18:287-90. [PMID: 15198118 DOI: 10.1191/0269216304pm895oa] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A randomised controlled pilot study was carried out to examine the effects of adjunctive aromatherapy massage on mood, quality of life and physical symptoms in patients with cancer attending a specialist unit. Participants were randomised to conventional day care alone or day care plus weekly aromatherapy massage using a standardised blend of oils for four weeks. At baseline and at weekly intervals, patients rated their mood, quality of life and the intensity and bother of two symptoms most important to them. Forty-six patients were recruited to the study. Due to a large number of withdrawals, only 11 of 23 (48%) patients in the aromatherapy group and 18 of 23 (78%) in the control group completed all four weeks. Mood, physical symptoms and quality of life improved in both groups. There was no statistically significant difference between groups in any of the outcome measures. Despite a lack of measurable benefit, all patients were satisfied with the aromatherapy and wished to continue. Whilst this pilot study has shown that a randomised controlled trial of complementary therapy is feasible, it has also identified several areas that would require further consideration when designing future studies, e.g., the recruitment and retention of appropriate numbers of patients and the outcome measures used.
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Affiliation(s)
- Andrew Wilcock
- Hayward House Macmillan Specialist Palliative Care Cancer Unit, Nottingham City Hospital NHS Trust, Hucknall Road, Nottingham NG5 1PB, UK.
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Carey AM, Archer JN, Priore JD, Kotula AW, Acosta-Stein L. Histologic detection of cardiac musculature, soy flour, and partially defatted tissue in ground beef: interlaboratory study. J Assoc Off Anal Chem 1984; 67:16-9. [PMID: 6538194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A collaborative study was designed and conducted to evaluate the accuracy of a procedure for the histologic detection of cardiac muscle, soy flour, and partially defatted tissue that may occur as adulterants in ground beef. Ground beef samples were prepared containing 0, 3, 5, 10, and 15% of each of the 3 adulterants. Five samples of each composition at each of the 5 dilutions, for a total of 75 unknown samples, were analyzed at each of 5 participating laboratories. The study revealed that this technique is reliable for the detection of these adulterants in ground beef.
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Carey AM, Archer JN, Priore JD, Kotula AW, Cannon LD, Carey AM, Deshmukh DR, Dyer JE, Glenn MW, Langheinrich KA. Histologic Detection of Cardiac Musculature, Soy Flour, and Partially Defatted Tissue in Ground Beef: Interlaboratory Study. J AOAC Int 1984. [DOI: 10.1093/jaoac/67.1.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
A collaborative study was designed and conducted to evaluate the accuracy of a procedure for the histologic detection of cardiac muscle, soy flour, and partially defatted tissue that may occur as adulterants in ground beef. Ground beef samples were prepared containing 0, 3, 5, 10, and 15% of each of the 3 adulterants. Five samples of each composition at each of the 5 dilutions, for a total of 75 unknown samples, were analyzed at each of 5 participating laboratories. The study revealed that this technique is reliable for the detection of these adulterants in ground beef.
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Affiliation(s)
- Albert M Carey
- U.S. Department of Agriculture, Food Safety and Inspection Service, Pathology Branch, Beltsville, MD 20705
| | - Jean N Archer
- U.S. Department of Agriculture, Food Safety and Inspection Service, Pathology Branch, Beltsville, MD 20705
| | - Joseph D Priore
- U.S. Department of Agriculture, Food Safety and Inspection Service, Pathology Branch, Beltsville, MD 20705
| | - Anthony W Kotula
- U.S. Department of Agriculture, Food Safety and Inspection Service, Pathology Branch, Beltsville, MD 20705
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Angus BL, Carey AM, Caron DA, Kropinski AM, Hancock RE. Outer membrane permeability in Pseudomonas aeruginosa: comparison of a wild-type with an antibiotic-supersusceptible mutant. Antimicrob Agents Chemother 1982; 21:299-309. [PMID: 6803666 PMCID: PMC181877 DOI: 10.1128/aac.21.2.299] [Citation(s) in RCA: 190] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The Pseudomonas aeruginosa mutant Z61 has been shown to be highly supersusceptible to a wide range of antibiotics, including beta-lactams, aminoglycosides, rifampin, tetracycline, and chloramphenicol (W. Zimmerman, Int. J. Clin. Pharmacol. Biopharm. 17:131-134, 1979). Spontaneous revertants were isolated, using gentamicin or carbenicillin as selective agents, and shown to have two patterns of susceptibility to a group of 12 antibiotics. Partial revertants had 2- to 10-fold greater resistance to these antibiotics than mutant Z61, whereas full revertants had antibiotic susceptibilities indistinguishable from those of the wild-type strain K799, from which mutant Z61 had been derived. Uptake of a chromogenic beta-lactam nitrocefin was studied in both uninduced and induced cells of all strains by measuring the steady-state rate of nitrocefin hydrolysis by the inducible, periplasmic beta-lactamase in both whole and broken cells. This demonstrated that outer membrane permeability decreased as antibiotic resistance increased in the series mutant Z61, partial revertants, wild type, and full revertants. The data were consistent with the idea of low outer membrane permeability being caused by a low proportion of open functional porins in the outer membrane as the reason for the high natural antibiotic resistance of wild-type P, aeruginosa strains. In addition, it was observed that levels of benzylpenicillin below the minimal inhibitory concentration for mutant Z61 failed to induce beta-lactamase production. The possibility that this was related to the observed increase in outer membrane permeability is discussed. Preliminary evidence is presented that the pore-forming outer membrane porin protein F is not altered in mutant Z61.
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Smith RE, Carey AM, Damare JM, Hetrick FM, Johnston RW, Lee WH. Evaluation of iron dextran and mucin for enhancement of the virulence of Yersinia enterocolitica serotype O:3 in mice. Infect Immun 1981; 34:550-60. [PMID: 7309239 PMCID: PMC350903 DOI: 10.1128/iai.34.2.550-560.1981] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The pathogenic role of Yersinia enterocolitica serotypes O:3, O:8, and O:9 in human infections is well documented. Whereas the virulence of the O:8 strains can be readily demonstrated in mice by 50% lethal dose determinations, the O:3 and O:9 strains have no lethal effect on mice by any route of inoculation. A mouse virulence test for the O:3 and O:9 strains is described. Y. enterocolitica strains were first tested for the presence of virulence-associated plasmid characteristics by auto-agglutination and gel electrophoresis procedures before mouse virulence determinations. The 50% lethal dose of the O:3 strains injected intraperitoneally with 2.5% mucin was about 10(7) colony-forming units. However, histological examinations showed that mucin allowed the growth of Y enterocolitica on the surface of the livers and spleens of the mice without internal lesions. The 50% lethal dose of the same O:3 strains injected intraperitoneally with 1 ml of 10% iron dextran in saline was about 10(5) to 10(6) colony-forming units, and the nonlethal infective dose with typical lesion development was 20 to 200 colony-forming units. The infected mice developed symptoms and extensive liver and spleen lesions which differed from those in mice infected intraperitoneally with the virulent O:8 strains. These results showed that the virulence of the O:3 Y. enterocolitica strains can be measured by intraperitoneal injection with iron dextran. This procedure was used to test the virulence of food isolates, plasmidless strains, and the effect of growth temperatures.
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Abstract
The Pseudomonas aeruginosa outer membrane was isolated with attached peptidoglycan and fractionated with Triton X-100, ethylenediaminetetraacetate, and lysozyme. The data suggest that major outer membrane proteins F, H2, and I are noncovalently associated with the peptidoglycan.
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Abstract
A number of polyacrylamide gel systems and solubilization procedures were studied to define the number and nature of "major" polypeptide bands in the outer membrane of Pseudomonas aeruginosa. It was shown that five of the eight major outer membrane proteins were "heat modifiable" in that their mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was determined by the solubilization temperature. Four of these heat-modifiable proteins had characteristics similar to protein II of the Escherichia coli outer membrane. Addition of lipopolysaccharide subsequent to solubilization caused reversal of the heat modification. The other heat-modifiable protein, the porin protein F, was unusually stable to sodium dodecyl sulfate. Long periods of boiling in sodium dodecyl sulfate were required to cause conversion to the heat-modified form. This was demonstrated both with outer membrane-associated and purified lipopolysaccharide-depleted protein F. Furthermore, lipopolysaccharide treatment had no effect on the mobility of heat-modified protein F. Thus it is concluded that protein F represents a new class of heat-modifiable protein. It was further demonstrated that the electrophoretic mobility of protein F was modified by 2-mercaptoethanol and that the 2-mercaptoethanol and heat modification of mobility were independent of one another. The optimal conditions for the examination of the outer membrane proteins of P. aeruginosa by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis are discussed.
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Migaki G, Carey AM. Malignant mastocytoma in a cow. Am J Vet Res 1972; 33:253-6. [PMID: 4621698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Migaki G, Garner FM, Carey AM. Metastatic transitional cell carcinoma of the bovine urinary bladder. A report on two cases. Cornell Vet 1971; 61:59-70. [PMID: 5099819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Migaki G, Carey AM, Turnquest RU, Garner FM. Pathology of bovine uterine adenocarcinoma. J Am Vet Med Assoc 1970; 157:1577-84. [PMID: 4098649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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