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Conley SM, Stuck MW, Watson JN, Zulliger R, Burnett JL, Naash MI. Prph2 initiates outer segment morphogenesis but maturation requires Prph2/Rom1 oligomerization. Hum Mol Genet 2019; 28:459-475. [PMID: 30307502 PMCID: PMC6337695 DOI: 10.1093/hmg/ddy359] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/05/2018] [Indexed: 12/15/2022] Open
Abstract
The retinal disease gene peripherin 2 (PRPH2) is essential for the formation of photoreceptor outer segments (OSs), where it functions in oligomers with and without its homologue ROM1. However, the precise role of these proteins in OS morphogenesis is not understood. By utilizing a knock-in mouse expressing a chimeric protein comprised of the body of Rom1 and the C-terminus of Prph2 (termed RRCT), we find that the Prph2 C-terminus is necessary and sufficient for the initiation of OSs, while OS maturation requires the body of Prph2 and associated large oligomers. Importantly, dominant-negative physiological and biochemical defects in RRCT heterozygous rods are rescued by removing Rom1, suggesting Rom1 is a regulator for OS formation. Our experiments evaluating Prph2 trafficking show that Rom1 is a key determinant of whether Prph2 complexes utilize conventional versus unconventional (Golgi bypass) secretory pathways to reach the OS. These findings significantly advance our understanding of the molecular underpinnings of OS morphogenesis and particularly the role of Rom1.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael W Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jamie N Watson
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rahel Zulliger
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Justin L Burnett
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA,To whom correspondence should be addressed at: Department of Biomedical Engineering University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA. Tel: +713 7431651; E-mail:
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Chuang WC, Garmestani A, Eason TN, Spanbauer TL, Fried-Petersen HB, Roberts CP, Sundstrom SM, Burnett JL, Angeler DG, Chaffin BC, Gunderson L, Twidwell D, Allen CR. Enhancing quantitative approaches for assessing community resilience. J Environ Manage 2018; 213:353-362. [PMID: 29502020 PMCID: PMC6748383 DOI: 10.1016/j.jenvman.2018.01.083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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] [Received: 08/15/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 05/07/2023]
Abstract
Scholars from many different intellectual disciplines have attempted to measure, estimate, or quantify resilience. However, there is growing concern that lack of clarity on the operationalization of the concept will limit its application. In this paper, we discuss the theory, research development and quantitative approaches in ecological and community resilience. Upon noting the lack of methods that quantify the complexities of the linked human and natural aspects of community resilience, we identify several promising approaches within the ecological resilience tradition that may be useful in filling these gaps. Further, we discuss the challenges for consolidating these approaches into a more integrated perspective for managing social-ecological systems.
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Affiliation(s)
- W C Chuang
- National Research Council, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA
| | - A Garmestani
- U.S. Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA.
| | - T N Eason
- U.S. Environmental Protection Agency, Office of Research and Development, 109 T. W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - T L Spanbauer
- National Research Council, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA
| | - H B Fried-Petersen
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, SE-750 07, Sweden
| | - C P Roberts
- School of Natural Resources, University of Nebraska-Lincoln, 103 Hardin Hall, 3310, Holdrege St., NE, 68583, USA
| | - S M Sundstrom
- School of Natural Resources, University of Nebraska-Lincoln, 103 Hardin Hall, 3310, Holdrege St., NE, 68583, USA
| | - J L Burnett
- School of Natural Resources, University of Nebraska-Lincoln, 103 Hardin Hall, 3310, Holdrege St., NE, 68583, USA
| | - D G Angeler
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, SE-750 07, Sweden
| | - B C Chaffin
- W.A. Franke College of Forestry & Conservation, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA
| | - L Gunderson
- Department of Environmental Sciences, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - D Twidwell
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68503-0984, USA
| | - C R Allen
- U.S. Geological Survey, Nebraska Cooperative Fish and Wildlife Research Unit, University of Nebraska-Lincoln, 103 Hardin Hall, 3310 Holdrege St., Lincoln, NE, 68583, USA
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Britton R, Davies AV, Burnett JL, Jackson MJ. A high-efficiency HPGe coincidence system for environmental analysis. J Environ Radioact 2015; 146:1-5. [PMID: 25875083 DOI: 10.1016/j.jenvrad.2015.03.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/17/2015] [Accepted: 03/27/2015] [Indexed: 06/04/2023]
Abstract
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a network of certified laboratories which must meet certain sensitivity requirements for CTBT relevant radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), a high-efficiency, dual-detector gamma spectroscopy system has been developed to improve the sensitivity of measurements for treaty compliance, greatly reducing the time required for each sample. Utilising list-mode acquisition, each sample can be counted once, and processed multiple times to further improve sensitivity. For the 8 key radionuclides considered, Minimum Detectable Activities (MDA's) were improved by up to 37% in standard mode (when compared to a typical CTBT detector system), with the acquisition time required to achieve the CTBT sensitivity requirements reduced from 6 days to only 3. When utilising the system in coincidence mode, the MDA for (60) Co in a high-activity source was improved by a factor of 34 when compared to a standard CTBT detector, and a factor of 17 when compared to the dual-detector system operating in standard mode. These MDA improvements will allow the accurate and timely quantification of radionuclides that decay via both singular and cascade γ emission, greatly enhancing the effectiveness of CTBT laboratories.
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Affiliation(s)
- R Britton
- AWE, Aldermaston, Reading, Berkshire, RG7 4PR, UK; University of Surrey, Guildford, GU2 7XH, UK.
| | - A V Davies
- AWE, Aldermaston, Reading, Berkshire, RG7 4PR, UK
| | - J L Burnett
- University of Surrey, Guildford, GU2 7XH, UK
| | - M J Jackson
- AWE, Aldermaston, Reading, Berkshire, RG7 4PR, UK
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Britton R, Burnett JL, Davies AV, Regan PH. Maximising the sensitivity of a γ spectrometer for low-energy, low-activity radionuclides using Monte Carlo simulations. J Environ Radioact 2014; 134:1-5. [PMID: 24631843 DOI: 10.1016/j.jenvrad.2014.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 01/13/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
Monte-Carlo simulations have been utilised to determine the optimum material and thickness for a γ spectrometer to be used for the assay of radionuclides that emit radiation in the 50-300 keV energy range. Both HPGe and LaBr3(Ce) materials were initially considered for use, however the additional background radiation and lack of resolution in the latter drove the selection of HPGe for further optimisation. Multiple thicknesses were considered for the HPGe detector, with the aim of improving the sensitivity of the system by maximising the efficiency for low energy emissions, and reducing the probability of interaction with (and therefore the continuum from) higher energy photons. The minimum amount of material needed to achieve this was found to be 15 mm for a source that is dominated by high energy (>2.614 MeV) photons, and 20-30 mm for a typical reference source (with photons of energy 59.54 keV-2.614 MeV).
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Affiliation(s)
- R Britton
- University of Surrey, Guildford GU2 7XH, UK; AWE, Aldermaston, Reading, Berkshire RG7 4PR, UK.
| | - J L Burnett
- AWE, Aldermaston, Reading, Berkshire RG7 4PR, UK
| | - A V Davies
- AWE, Aldermaston, Reading, Berkshire RG7 4PR, UK
| | - P H Regan
- University of Surrey, Guildford GU2 7XH, UK
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Conley SM, Stuck MW, Burnett JL, Chakraborty D, Azadi S, Fliesler SJ, Naash MI. Insights into the mechanisms of macular degeneration associated with the R172W mutation in RDS. Hum Mol Genet 2014; 23:3102-14. [PMID: 24463884 DOI: 10.1093/hmg/ddu014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mutations in the photoreceptor tetraspanin gene peripherin-2/retinal degeneration slow (PRPH2/RDS) cause both rod- and cone-dominant diseases. While rod-dominant diseases, such as autosomal dominant retinitis pigmentosa, are thought to arise due to haploinsufficiency caused by loss-of-function mutations, the mechanisms underlying PRPH2-associated cone-dominant diseases are unclear. Here we took advantage of a transgenic mouse line expressing an RDS mutant (R172W) known to cause macular degeneration (MD) in humans. To facilitate the study of cones in the heavily rod-dominant mouse retina, R172W mice were bred onto an Nrl(-/-) background (in which developing rods adopt a cone-like fate). In this model the R172W protein and the key RDS-binding partner, rod outer segment (OS) membrane protein 1 (ROM-1), were properly expressed and trafficked to cone OSs. However, the expression of R172W led to dominant defects in cone structure and function with equal effects on S- and M-cones. Furthermore, the expression of R172W in cones induced subtle alterations in RDS/ROM-1 complex assembly, specifically resulting in the formation of abnormal, large molecular weight ROM-1 complexes. Fundus imaging demonstrated that R172W mice developed severe clinical signs of disease nearly identical to those seen in human MD patients, including retinal degeneration, retinal pigment epithlium (RPE) defects and loss of the choriocapillaris. Collectively, these data identify a primary disease-causing molecular defect in cone cells and suggest that RDS-associated disease in patients may be a result of this defect coupled with secondary sequellae involving RPE and choriocapillaris cell loss.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Michael W Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Justin L Burnett
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Dibyendu Chakraborty
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Seifollah Azadi
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
| | - Steven J Fliesler
- Research Service, Veterans Administration Western New York Healthcare System, Buffalo, NY 14215, USA Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, University at Buffalo-S.U.N.Y, Buffalo, NY 14215, USA
| | - Muna I Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 781, Oklahoma City, OK 73104, USA
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Burnett JL, Croudace IW, Warwick PE. Pre-concentration of naturally occurring radionuclides and the determination of (212)Pb from fresh waters. J Environ Radioact 2011; 102:326-330. [PMID: 21306802 DOI: 10.1016/j.jenvrad.2011.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 01/09/2011] [Accepted: 01/12/2011] [Indexed: 05/30/2023]
Abstract
A novel technique has been developed for determining the (212)Pb activity of fresh waters. This is of interest to environmental monitoring programmes that utilise gross α-activity methods to screen for anthropogenic radionuclides. The contribution from (212)Pb varies, and is difficult to experimentally measure due to its relatively short half-life (t(½) = 10.6 h) and low environmental activity (<0.1 Bq l(-1)). The use of a three-stage technique that encompasses a unique form of pre-concentration, separation and analysis by liquid scintillation counting allows a lower detection limit of 0.006 Bq l(-1) with a chemical yield of 92.5 ± 5.6%. The measurement can be obtained within 7 h of sample collection, and is calculated using the radioactive decay of (212)Bi. Other naturally occurring radionuclides may also be extracted using the pre-concentration stage of the technique, with efficiencies above 90% at a range of pH values.
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Affiliation(s)
- J L Burnett
- Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR, UK.
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Abstract
Sudden increases in the background gamma-radiation dose may occur due to the removal of (222)Rn and (220)Rn progeny from the atmosphere by wet deposition mechanisms. This contribution has been measured using a Geiger-Muller detector at the Atomic Weapons Establishment (Aldermaston, UK) during July 2005-April 2006. The results are approximated by a log-normal distribution and there were nine separate occurrences of the gamma-radiation dose exceeding 125% of the geometric mean value. The increases were associated with periods of heavy rainfall, although no correlation was evident between the dose rate and the amount of rainfall, as increased rainfall dilutes the activity further rather than increasing its atmospheric removal. The events were preceded by periods of fine weather and atmospheric stability that allow for the build-up of (222)Rn and (220)Rn progeny. Similar increases in gamma-radiation dose have been measured at a nearby monitoring station situated approximately 11 miles from Aldermaston. Increases in gamma-radiation dose during heavy rainfall have also been observed throughout the UK, that followed the trajectory of an air mass. All events decreased to typical values within 1-2 h as the water permeated into the ground below and the radioactivity decayed away.
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Affiliation(s)
- J L Burnett
- Atomic Weapons Establishment, Aldermaston, Reading, Berkshire, UK
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