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Bachman TN, Nouraie SM, Williams LE, Boisen ML, Kim K, Borovetz HS, Schaub R, Kormos RL, Simon MA. Feasibility of a Composite Measure of Pulmonary Vascular Impedance and Application to Patients with Chronic RV Failure Post LVAD Implant. Cardiovasc Eng Technol 2024; 15:1-11. [PMID: 38129334 DOI: 10.1007/s13239-023-00671-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 06/20/2023] [Indexed: 12/23/2023]
Abstract
Pulmonary vascular impedance (PVZ) describes RV afterload in the frequency domain and has not been studied extensively in LVAD patients. We sought to determine (1) feasibility of calculating a composite (c)PVZ using standard of care (SoC), asynchronous, pulmonary artery pressure (PAP) and flow (PAQ) waveforms; and (2) if chronic right ventricular failure (RVF) post-LVAD implant was associated with changes in perioperative cPVZ.PAP and PAQ were obtained via SoC procedures at three landmarks: T(1), Retrospectively, pre-operative with patient conscious; and T(2) and T(3), prospectively with patient anesthetized, and either pre-sternotomy or chest open with LVAD, respectively. Additional PAP's were taken at T(4), following chest closure; and T(5), 4-24 h post chest closure. Harmonics (z) were calculated by Fast Fourier Transform (FFT) with cPVZ(z) = FFT(PAP)/FFT(PAQ). Total pulmonary resistance Z(0); characteristic impedance Zc, mean of cPVZ(2-4); and vascular stiffness PVS, sum of cPVZ(1,2), were compared at T(1,2,3) between +/-RVF groups.Out of 51 patients, nine experienced RVF. Standard hemodynamics and changes in cPVZ-derived parameters were not significant between groups at any T.In conclusion, cPVZ calculated from SoC measures is possible. Although data that could be obtained were limited it suggests no difference in RV afterload for RVF patients post-implant. If confirmed in larger studies, focus should be placed on cardiac function in these subjects.
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Affiliation(s)
- Timothy N Bachman
- Dept. of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
| | - S M Nouraie
- Dept. Of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - L E Williams
- Dept. of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - M L Boisen
- Dept. of Anesthesia, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - K Kim
- Dept. of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - H S Borovetz
- Dept. of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - R Schaub
- Dept. of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - R L Kormos
- Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - M A Simon
- Division of Cardiology, Dept. of Medicine, University of California, San Francisco, San Francisco, CA, United States
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Batool TS, Aslam R, Gul A, Paracha RZ, Ilyas M, De Abreu K, Munir F, Amir R, Williams LE. Genome-wide analysis of heavy metal ATPases (HMAs) in Poaceae species and their potential role against copper stress in Triticum aestivum. Sci Rep 2023; 13:7551. [PMID: 37160901 PMCID: PMC10170112 DOI: 10.1038/s41598-023-32023-7] [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] [Received: 12/13/2022] [Accepted: 03/21/2023] [Indexed: 05/11/2023] Open
Abstract
Plants require copper for normal growth and development and have evolved an efficient system for copper management based on transport proteins such as P1B-ATPases, also known as heavy metal ATPases (HMAs). Here, we report HMAs in eleven different Poaceae species, including wheat. Furthermore, the possible role of wheat HMAs in copper stress was investigated. BlastP searches identified 27 HMAs in wheat, and phylogenetic analysis based on the Maximum Likelihood method demonstrated a separation into four distinct clades. Conserved motif analysis, domain identification, gene structure, and transmembrane helices number were also identified for wheat HMAs using computational tools. Wheat seedlings grown hydroponically were subjected to elevated copper and demonstrated toxicity symptoms with effects on fresh weight and changes in expression of selected HMAs TaHMA7, TaHMA8, and TaHMA9 were upregulated in response to elevated copper, suggesting a role in wheat copper homeostasis. Further investigations on these heavy metal pumps can provide insight into strategies for enhancing crop heavy metal tolerance in the face of heavy metal pollution.
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Affiliation(s)
- Tuba Sharf Batool
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Roohi Aslam
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan.
| | - Alvina Gul
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Rehan Zafar Paracha
- School of Interdisciplinary Engineering & Sciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Mahnoor Ilyas
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Kathryn De Abreu
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Faiza Munir
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Rabia Amir
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Lorraine E Williams
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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Farthing EC, Henbest KC, Garcia‐Becerra T, Peaston KA, Williams LE. Dissecting the relative contribution of ECA3 and group 8/9 cation diffusion facilitators to manganese homeostasis in Arabidopsis thaliana. Plant Direct 2023; 7:e495. [PMID: 37228331 PMCID: PMC10202827 DOI: 10.1002/pld3.495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 03/14/2023] [Accepted: 03/27/2023] [Indexed: 05/27/2023]
Abstract
Manganese (Mn) is an essential micronutrient for plant growth but becomes toxic when present in excess. A number of Arabidopsis proteins are involved in Mn transport including ECA3, MTPs, and NRAMPs; however, their relative contributions to Mn homeostasis remain to be demonstrated. A major focus here was to clarify the importance of ECA3 in responding to Mn deficiency and toxicity using a range of mutants. We show that ECA3 localizes to the trans-Golgi and plays a major role in response to Mn deficiency with severe effects seen in eca3 nramp1 nramp2 under low Mn supply. ECA3 plays a minor role in Mn-toxicity tolerance, but only when the cis-Golgi-localized MTP11 is non-functional. We also use mutants and overexpressors to determine the relative contributions of MTP members to Mn homeostasis. The trans-Golgi-localized MTP10 plays a role in Mn-toxicity tolerance, but this is only revealed in mutants when MTP8 and MTP11 are non-functional and when overexpressed in mtp11 mutants. MTP8 and MTP10 confer greater Mn-toxicity resistance to the pmr1 yeast mutant than MTP11, and an important role for the first aspartate in the fifth transmembrane domain DxxxD motif is demonstrated. Overall, new insight into the relative influence of key transporters in Mn homeostasis is provided.
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Affiliation(s)
- Emily C. Farthing
- School of Biological SciencesUniversity of SouthamptonSouthamptonHampshireUK
| | - Kate C. Henbest
- School of Biological SciencesUniversity of SouthamptonSouthamptonHampshireUK
| | | | - Kerry A. Peaston
- School of Biological SciencesUniversity of SouthamptonSouthamptonHampshireUK
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Rowley PA, Paukner MJ, Eisenmenger LB, Field AS, Davidson RJ, Johnson SC, Asthana S, Chin NA, Prabhakaran V, Bendlin BB, Postle BR, Goldsmith HH, Carlsson CM, Brooks MA, Kalin NH, Williams LE, Rowley HA. Incidental Findings from 16,400 Brain MRI Examinations of Research Volunteers. AJNR Am J Neuroradiol 2023; 44:417-423. [PMID: 36927761 PMCID: PMC10084899 DOI: 10.3174/ajnr.a7821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/20/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND AND PURPOSE Incidental findings are discovered in neuroimaging research, ranging from trivial to life-threatening. We describe the prevalence and characteristics of incidental findings from 16,400 research brain MRIs, comparing spontaneous detection by nonradiology scanning staff versus formal neuroradiologist interpretation. MATERIALS AND METHODS We prospectively collected 16,400 brain MRIs (7782 males, 8618 females; younger than 1 to 94 years of age; median age, 38 years) under an institutional review board directive intended to identify clinically relevant incidental findings. The study population included 13,150 presumed healthy volunteers and 3250 individuals with known neurologic diagnoses. Scanning staff were asked to flag concerning imaging findings seen during the scan session, and neuroradiologists produced structured reports after reviewing every scan. RESULTS Neuroradiologists reported 13,593/16,400 (83%) scans as having normal findings, 2193/16,400 (13.3%) with abnormal findings without follow-up recommended, and 614/16,400 (3.7%) with "abnormal findings with follow-up recommended." The most common abnormalities prompting follow-up were vascular (263/614, 43%), neoplastic (130/614, 21%), and congenital (92/614, 15%). Volunteers older than 65 years of age were significantly more likely to have scans with abnormal findings (P < .001); however, among all volunteers with incidental findings, those younger than 65 years of age were more likely to be recommended for follow-up. Nonradiologists flagged <1% of MRIs containing at least 1 abnormality reported by the neuroradiologists to be concerning enough to warrant further evaluation. CONCLUSIONS Four percent of individuals who undergo research brain MRIs have an incidental, potentially clinically significant finding. Routine neuroradiologist review of all scans yields a much higher rate of significant lesion detection than selective referral from nonradiologists who perform the examinations. Workflow and scan review processes need to be carefully considered when designing research protocols.
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Affiliation(s)
- P A Rowley
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Departments of Radiology (P.A.R., LB.E., A.S.F., V.P., H.A.R.)
| | | | - L B Eisenmenger
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Departments of Radiology (P.A.R., LB.E., A.S.F., V.P., H.A.R.)
| | - A S Field
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Departments of Radiology (P.A.R., LB.E., A.S.F., V.P., H.A.R.)
| | - R J Davidson
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Psychology (R.J.D., B.R.P., H.H.G.)
| | - S C Johnson
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Wisconsin Alzheimer's Disease Research Center (S.C.J., S.A., B.B.B., C.M.C.)
- Departments of Medicine (S.C.J., S.A., N.A.C., B.B.B., C.M.C.)
| | - S Asthana
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Wisconsin Alzheimer's Disease Research Center (S.C.J., S.A., B.B.B., C.M.C.)
- Departments of Medicine (S.C.J., S.A., N.A.C., B.B.B., C.M.C.)
| | - N A Chin
- Departments of Medicine (S.C.J., S.A., N.A.C., B.B.B., C.M.C.)
| | - V Prabhakaran
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Departments of Radiology (P.A.R., LB.E., A.S.F., V.P., H.A.R.)
| | - B B Bendlin
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Wisconsin Alzheimer's Disease Research Center (S.C.J., S.A., B.B.B., C.M.C.)
- Departments of Medicine (S.C.J., S.A., N.A.C., B.B.B., C.M.C.)
| | - B R Postle
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Psychology (R.J.D., B.R.P., H.H.G.)
| | - H H Goldsmith
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Psychology (R.J.D., B.R.P., H.H.G.)
| | - C M Carlsson
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Wisconsin Alzheimer's Disease Research Center (S.C.J., S.A., B.B.B., C.M.C.)
- Departments of Medicine (S.C.J., S.A., N.A.C., B.B.B., C.M.C.)
| | - M A Brooks
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Orthopedics (M.A.B.)
| | - N H Kalin
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Psychiatry (N.H.K., L.E.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - L E Williams
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Psychiatry (N.H.K., L.E.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - H A Rowley
- From the University of Wisconsin School of Medicine and Public Health (P.A.R., L.B.E., A.S.F., R.J.D., S.C.J., S.A., V.P., B.B.B., B.R.P., H.H.G., C.M.C., M.A.B., N.H.K., L.E.W., H.A.R.)
- Departments of Radiology (P.A.R., LB.E., A.S.F., V.P., H.A.R.)
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McElrone AJ, Manuck CM, Brodersen CR, Patakas A, Pearsall KR, Williams LE. Functional hydraulic sectoring in grapevines as evidenced by sap flow, dye infusion, leaf removal and micro-computed tomography. AoB Plants 2021; 13:plab003. [PMID: 33841756 PMCID: PMC8023307 DOI: 10.1093/aobpla/plab003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 01/08/2021] [Indexed: 05/24/2023]
Abstract
The supply of water to a plant canopy is dependent on the xylem pathway connecting roots to leaves. In some plants, sectored xylem pathways can restrict resource distribution, resulting in variable quality of organs in the shoots, yet little is known about the effects of sectoring in crop cultivars. In this study, we combined sap flow measurements and infusion of xylem-specific dyes to document functional conductive area and flow pathways from roots to shoots of 20-year-old Thompson Seedless and 8-year-old Chardonnay grapevines. Sap flow measurements and dye infusion demonstrated that water flowed predominantly in discrete xylem (visually identifiable from the trunk surface) sectors along the trunk axis, each supplying limited portions of the canopy. Functional conductive area in the trunk was proportional to that in the shoots even though sector size varied considerably between vines. Leaf area removal experiments further demonstrated sectoring in grapevines; sap flow decreased by >90 % in trunk sectors connected to excised shoots while it remained constant in trunk sectors supplying intact portions of the canopy. Despite the functional sectoring in grapevines, a high degree of interconnectivity of trunk xylem in the tangential direction was confirmed with synchrotron-based micro-computed tomography (microCT) and dye crossover infusion studies. Fruit attached to dyed canes was also similarly sectored; no clusters exhibited dye on non-dyed canes, while 97 % of clusters attached to dyed canes exhibited dye infusion. The dye travelled down the cluster rachis and appeared to accumulate at the pedicel/berry junction, but only on dyed canes. These findings suggest that xylem in grapevine trunks is integrated anatomically, but functions in a sectored manner due to high axial hydraulic conductivity. The functional sectoring of grapevine xylem documented here has important implications for management practices in vineyards and for fruit cluster uniformity within single grapevine.
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Affiliation(s)
- A J McElrone
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA 95616, USA
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - C M Manuck
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA 95616, USA
| | | | - A Patakas
- University of Ioannina, Ioannina, 451 10, Greece
| | - K R Pearsall
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - L E Williams
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
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Ibuot A, Webster RE, Williams LE, Pittman JK. Increased metal tolerance and bioaccumulation of zinc and cadmium in Chlamydomonas reinhardtii expressing a AtHMA4 C-terminal domain protein. Biotechnol Bioeng 2020; 117:2996-3005. [PMID: 32579250 DOI: 10.1002/bit.27476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/05/2020] [Accepted: 06/23/2020] [Indexed: 02/03/2023]
Abstract
The use of microalgal biomass for metal pollutant bioremediation might be improved by genetic engineering to modify the selectivity or capacity of metal biosorption. A plant cadmium (Cd) and zinc (Zn) transporter (AtHMA4) was used as a transgene to increase the ability of Chlamydomonas reinhardtii to tolerate 0.2 mM Cd and 0.3 mM Zn exposure. The transgenic cells showed increased accumulation and internalization of both metals compared to wild-type. AtHMA4 was expressed either as the full-length (FL) protein or just the C-terminal (CT) tail, which is known to have metal-binding sites. Similar Cd and Zn tolerance and accumulation was observed with expression of either the FL protein or CT domain, suggesting that enhanced metal tolerance was mainly due to increased metal binding rather than metal transport. The effectiveness of the transgenic cells was further examined by immobilization in calcium alginate to generate microalgal beads that could be added to a metal contaminated solution. Immobilization maintained metal tolerance, while AtHMA4-expressing cells in alginate showed a concentration-dependent increase in metal biosorption that was significantly greater than alginate beads composed of wild-type cells. This demonstrates that expressing AtHMA4 FL or CT has great potential as a strategy for bioremediation using microalgal biomass.
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Affiliation(s)
- Aniefon Ibuot
- Department of Science Technology, Akwa Ibom State Polytechnic, Ikot Ekpene, Akwa Ibom, Nigeria
| | - Rachel E Webster
- The Manchester Museum, The University of Manchester, Manchester, UK
| | | | - Jon K Pittman
- Department of Earth and Environmental Sciences, School of Natural Sciences, The University of Manchester, Manchester, UK
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Abdou Y, Williams LE, Kalinski P, Opyrchal M. Abstract OT2-06-02: Chemokine modulation to enhance the effectiveness of pembrolizumab in patients with metastatic triple negative breast cancer. Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-ot2-06-02] [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: 11/16/2022]
Abstract
Abstract
Background: Triple negative breast cancer (TNBC) is found in approximately 15-20% of all breast cancer, and is associated with poor prognosis, early relapse and a significantly shorter survival following recurrence. Early phase trials with immune checkpoint inhibitors have shown modest yet durable clinical responses with a tolerable safety profile. Strategies to sensitize these tumors to checkpoint inhibition will result in decreased morbidity and mortality.
Tumor infiltrating immune cells and intratumoral expression of PD-1/PD-L1/PD-L2 can predict patients' benefit from Pembrolizumab. Pre-clinical ex-vivo data show that chemokine modulating regimen consisting of Rintatolimod, IFNα and COX2 blocker (CKM), selectively attracts cytotoxic T cells into tumors, and increases intratumoral expression of PD-1/PD-L1/PD-L2, without enhancing soluble suppressive mechanisms. Furthermore, mouse data has shown safety of CKM and PD-1 blockade combination and efficacy in inducing long-term survival of mice with resistant tumors.
Clinical trials of CKM in Colon and ovarian cancer (NCT01545141, NCT02432378) demonstrated safety of Rintatolimod given with IFNα/COX2, and preliminary data show local efficacy in tumor microenvironment modulation.
Design: This is an open-label, single center, phase IIa study to test Chemokine modulating regimen (CKM) pre-treatment followed by Pembrolizumab in patients with metastatic TNBC, regardless of PD-1 expression, who progressed on ≥1 lines of therapy.
Patients are given pre-treatment CKM, which consists of Rintatolimod (200 mg IV), IFNα-2 (20 million units/m2 IV) and Celecoxib (200 mg po BID), on 3 consecutive days for a total of 2 cycles, one week apart. The patient is then treated with Pembrolizumab 200 mg IV every 3 weeks until disease progression, intolerable side effects or withdrawal from study for up to 24 months. Study includes pre- and post CKM treatment biopsies.
Eligibility: Major criteria include age ≥ 18 years, ECOG ≤ 1, histologically proven metastatic TNBC, normal organ and marrow function, no active autoimmune disease or history of transplant, no prior anti-PD1/PDL1 therapy.
Aims: Primary objective is to evaluate the overall response rate to the combination therapy per irRECIST criteria. Secondary objectives include safety profile of the combination therapy, determining progression free survival, overall survival and disease control rate. Other immune exploratory objectives will include baseline and CKM-induced predictive biomarkers of clinical activity of the combination treatment.
Statistical Methods: The study includes a safety lead-in of 6 patients and utilizes a Simon two-stage minimax design. 18 patients are enrolled into stage 1 of the study. If < 4 responses are observed, the treatment combination will not be considered promising and enrollment will be terminated. However, if ≥ 4 responses are observed, then an additional 19 patients will be enrolled into stage 2, for a total number of 37 patients. In stage 2, if ≥ 9 responses are observed, then the treatment combination will be considered promising for future study.
Citation Format: Abdou Y, Williams LE, Kalinski P, Opyrchal M. Chemokine modulation to enhance the effectiveness of pembrolizumab in patients with metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-06-02.
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Affiliation(s)
- Y Abdou
- Roswell Park Comprehensive Cancer Center, Buffalo, NY
| | - LE Williams
- Roswell Park Comprehensive Cancer Center, Buffalo, NY
| | - P Kalinski
- Roswell Park Comprehensive Cancer Center, Buffalo, NY
| | - M Opyrchal
- Roswell Park Comprehensive Cancer Center, Buffalo, NY
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Hippler FWR, Mattos-Jr D, Boaretto RM, Williams LE. Copper excess reduces nitrate uptake by Arabidopsis roots with specific effects on gene expression. J Plant Physiol 2018; 228:158-165. [PMID: 29933138 PMCID: PMC6090090 DOI: 10.1016/j.jplph.2018.06.005] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/09/2018] [Accepted: 06/10/2018] [Indexed: 05/09/2023]
Abstract
Nitrate uptake by plants is mediated by specific transport proteins in roots (NRTs), which are also dependent on the activity of proton pumps that energize the reaction. Nitrogen (N) metabolism in plants is sensitive to copper (Cu) toxicity conditions. To understand how Cu affects the uptake and assimilation processes, this study assesses the inhibitory effects of elevated Cu levels on the expression of genes related to N absorption, transport and assimilation in roots of Arabidopsis. Plants were grown hydroponically for 45 days, being exposed to a range of Cu concentrations in the last 72 h or alternatively exposed to 5.0 μM Cu for the last 15 days. High Cu levels decreased the uptake and accumulation of N in plants. It down-regulated the expression of genes encoding nitrate reductase (NR1), low-affinity nitrate transporters (NRT1 family) and bZIP transcription factors (TGA1 and TGA4) that regulate the expression of nitrate transporters. Cu toxicity also specifically down-regulated the plasma membrane proton pump, AHA2, whilst having little effect on AHA1 and AHA5. In contrast, there was an up-regulation of high-affinity nitrate transporters from the NRT2 family when exposed to medium level of Cu excess, but this was insufficient for restoring N absorption by roots to control levels. These results demonstrate that plants display specific responses to Cu toxicity, modulating the expression of particular genes related to nitrate uptake, such as low-affinity nitrate transporters and proton pumps.
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Affiliation(s)
- Franz W R Hippler
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil; University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
| | - Dirceu Mattos-Jr
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Rodrigo M Boaretto
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Lorraine E Williams
- University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
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9
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Giust D, Lucío MI, El-Sagheer AH, Brown T, Williams LE, Muskens OL, Kanaras AG. Graphene Oxide-Upconversion Nanoparticle Based Portable Sensors for Assessing Nutritional Deficiencies in Crops. ACS Nano 2018; 12:6273-6279. [PMID: 29873479 DOI: 10.1021/acsnano.8b03261] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [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: 05/06/2023]
Abstract
The development of innovative technologies to rapidly detect biomarkers associated with nutritional deficiencies in crops is highly relevant to agriculture and thus could impact the future of food security. Zinc (Zn) is an important micronutrient in plants, and deficiency leads to poor health, quality, and yield of crops. We have developed portable sensors, based on graphene oxide and upconversion nanoparticles, which could be used in the early detection of Zn deficiency in crops, sensing mRNAs encoding members of the ZIP-transporter family in crops. ZIPs are membrane transport proteins, some of which are up-regulated at the early stages of Zn deficiency, and they are part of the biological mechanism by which crops respond to nutritional deficiency. The principle of these sensors is based on the intensity of the optical output resulting from the interaction of oligonucleotide-coated upconversion nanoparticles and graphene oxide in the absence or presence of a specific oligonucleotide target. The sensors can reliably detect mRNAs in RNA extracts from plants using a smartphone camera. Our work introduces the development of accurate and highly sensitive sensors for use in the field to determine crop nutrient status and ultimately facilitate economically important nutrient management decisions.
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Affiliation(s)
| | | | - Afaf H El-Sagheer
- Department of Chemistry , University of Oxford, Chemistry Research Laboratory , 12 Mansfield Road , Oxford , OX1 3TA , U.K
- Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering , Suez University , Suez 43721 , Egypt
| | - Tom Brown
- Department of Chemistry , University of Oxford, Chemistry Research Laboratory , 12 Mansfield Road , Oxford , OX1 3TA , U.K
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10
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Hippler FWR, Dovis VL, Boaretto RM, Quaggio JA, Azevedo RA, Williams LE, Mattos D. Photosynthesis is differently regulated during and after copper-induced nutritional stress in citrus trees. Physiol Plant 2018; 163:399-413. [PMID: 29667213 DOI: 10.1111/ppl.12746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/28/2018] [Accepted: 04/10/2018] [Indexed: 06/08/2023]
Abstract
Antioxidant enzymatic responses in Citrus leaves under Cu-induced stress depends on rootstock genotypes. However, there is a lack of information about how woody plants recover growth capacity after exposure to elevated Cu and whether growth is affected by the redistribution of the metal to new vegetative parts and consequently whether photosynthesis is affected. Therefore, the biomass of plants and Cu concentrations in new leaf flushes were determined in young citrus trees grafted onto contrasting rootstocks [Swingle citrumelo (SW) and Rangpur lime (RL)]. Photosynthetic rate, chlorophyll fluorescence and antioxidant enzymatic systems were evaluated in plants previously grown in nutrient solution with Cu varying from low to high levels and with no added Cu. Both rootstocks exhibited reduced plant growth under Cu toxicity. However, trees grafted onto RL exhibited better growth recovery after Cu excess, which was dependent on the modulation of antioxidant enzyme activities in roots and leaves that maintained the integrity of the photosynthetic apparatus. In contrast, plants grafted onto SW exhibited a lower photosynthetic rate at the lowest available Cu concentration. Although the highest accumulation of Cu occurred in citrus roots, the redistribution of the nutrient to new vegetative parts was proportional to the Cu concentration in the roots.
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Affiliation(s)
- Franz W R Hippler
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Rod. Anhanguera, km 158, CP 04, CEP, 13490-970, Cordeirópolis, SP, Brazil
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, CP 9, Universidade de São Paulo, 13418-900, Piracicaba, SP, Brazil
| | - Veronica L Dovis
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Rod. Anhanguera, km 158, CP 04, CEP, 13490-970, Cordeirópolis, SP, Brazil
| | - Rodrigo M Boaretto
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Rod. Anhanguera, km 158, CP 04, CEP, 13490-970, Cordeirópolis, SP, Brazil
| | - Jose A Quaggio
- Centro de Solos e Recursos Ambientais, Instituto Agronômico, Av. Barão de Itapura, 1481, CP 28, CEP, 13020-902, Campinas, SP, Brazil
| | - Ricardo A Azevedo
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, CP 9, Universidade de São Paulo, 13418-900, Piracicaba, SP, Brazil
| | - Lorraine E Williams
- Biological Sciences, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton, SO17 1BJ, United Kingdom
| | - Dirceu Mattos
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Rod. Anhanguera, km 158, CP 04, CEP, 13490-970, Cordeirópolis, SP, Brazil
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11
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Papierniak A, Kozak K, Kendziorek M, Barabasz A, Palusińska M, Tiuryn J, Paterczyk B, Williams LE, Antosiewicz DM. Contribution of NtZIP1-Like to the Regulation of Zn Homeostasis. Front Plant Sci 2018; 9:185. [PMID: 29503658 PMCID: PMC5820362 DOI: 10.3389/fpls.2018.00185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/31/2018] [Indexed: 05/20/2023]
Abstract
Tobacco has frequently been suggested as a candidate plant species for use in phytoremediation of metal contaminated soil but knowledge on the regulation of its metal-homeostasis is still in the infancy. To identify new tobacco metal transport genes that are involved in Zn homeostasis a bioinformatics study using the tobacco genome information together with expression analysis was performed. Ten new tobacco metal transport genes from the ZIP, NRAMP, MTP, and MRP/ABCC families were identified with expression levels in leaves that were modified by exposure to Zn excess. Following exposure to high Zn there was upregulation of NtZIP11-like, NtNRAMP3, three isoforms of NtMTP2, three MRP/ABCC genes (NtMRP5-like, NtMRP10-like, and NtMRP14 like) and downregulation of NtZIP1-like and NtZIP4. This suggests their involvement in several processes governing the response to Zn-related stress and in the efficiency of Zn accumulation (uptake, sequestration, and redistribution). Further detailed analysis of NtZIP1-like provided evidence that it is localized at the plasma membrane and is involved in Zn but not Fe and Cd transport. NtZIP1-like is expressed in the roots and shoots, and is regulated developmentally and in a tissue-specific manner. It is highly upregulated by Zn deficiency in the leaves and the root basal region but not in the root apical zone (region of maturation and absorption containing root hairs). Thus NtZIP1-like is unlikely to be responsible for Zn uptake by the root apical region but rather in the uptake by root cells within the already mature basal zone. It is downregulated by Zn excess suggesting it is involved in a mechanism to protect the root and leaf cells from accumulating excess Zn.
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Affiliation(s)
- Anna Papierniak
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Katarzyna Kozak
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Maria Kendziorek
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Anna Barabasz
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Małgorzata Palusińska
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Jerzy Tiuryn
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Warsaw, Poland
| | - Bohdan Paterczyk
- Laboratory of Electron and Confocal Microscopy, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - Danuta M. Antosiewicz
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- *Correspondence: Danuta M. Antosiewicz,
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12
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Nazri AZ, Griffin JH, Peaston KA, Alexander‐Webber DG, Williams LE. F-group bZIPs in barley-a role in Zn deficiency. Plant Cell Environ 2017; 40:2754-2770. [PMID: 28763829 PMCID: PMC5656896 DOI: 10.1111/pce.13045] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [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: 08/28/2016] [Accepted: 07/09/2017] [Indexed: 05/13/2023]
Abstract
Zinc (Zn) deficiency negatively impacts the development and health of plants and affects crop yield. When experiencing low Zn, plants undergo an adaptive response to maintain Zn homeostasis. We provide further evidence for the role of F-group transcription factors, AtbZIP19 and AtbZIP23, in responding to Zn deficiency in Arabidopsis and demonstrate the sensitivity and specificity of this response. Despite their economic importance, the role of F-group bZIPs in cereal crops is largely unknown. Here, we provide new insights by functionally characterizing these in barley (Hordeum vulgare), demonstrating an expanded number of F-group bZIPs (seven) compared to Arabidopsis. The F-group barley bZIPs, HvbZIP56 and HvbZIP62, partially rescue the Zn-dependent growth phenotype and ZIP-transporter gene regulation of an Arabidopsis bzip19-4 bzip23-2 mutant. This supports a conserved mechanism of action in adapting to Zn deficiency. HvbZIP56 localizes to the cytoplasm and nucleus when expressed in Arabidopsis and tobacco. Promoter analysis demonstrates that the barley ZIP transporters that are upregulated under Zn deficiency contain cis Zn-deficiency response elements (ZDREs). ZDREs are also found in particular barley bZIP promoters. This study represents a significant step forward in understanding the mechanisms controlling Zn responses in cereal crops, and will aid in developing strategies for crop improvement.
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Affiliation(s)
| | | | - Kerry A. Peaston
- Biological SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
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13
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Aslam R, Williams LE, Bhatti MF, Virk N. Genome-wide analysis of wheat calcium ATPases and potential role of selected ACAs and ECAs in calcium stress. BMC Plant Biol 2017; 17:174. [PMID: 29078753 PMCID: PMC5658947 DOI: 10.1186/s12870-017-1112-5] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/09/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND P2- type calcium ATPases (ACAs-auto inhibited calcium ATPases and ECAs-endoplasmic reticulum calcium ATPases) belong to the P- type ATPase family of active membrane transporters and are significantly involved in maintaining accurate levels of Ca2+, Mn2+ and Zn2+ in the cytosol as well as playing a very important role in stress signaling, stomatal opening and closing and pollen tube growth. Here we report the identification and possible role of some of these ATPases from wheat. RESULTS In this study, ACA and ECA sequences of six species (belonging to Poaceae) were retrieved from different databases and a phylogenetic tree was constructed. A high degree of evolutionary relatedness was observed among P2 sequences characterized in this study. Members of the respective groups from different plant species were observed to fall under the same clade. This pattern highlights the common ancestry of P2- type calcium ATPases. Furthermore, qRT-PCR was used to analyse the expression of selected ACAs and ECAs from Triticum aestivum (wheat) under calcium toxicity and calcium deficiency. The data indicated that expression of ECAs is enhanced under calcium stress, suggesting possible roles of these ATPases in calcium homeostasis in wheat. Similarly, the expression of ACAs was significantly different in plants grown under calcium stress as compared to plants grown under control conditions. This gives clues to the role of ACAs in signal transduction during calcium stress in wheat. CONCLUSION Here we concluded that wheat genome consists of nine P2B and three P2A -type calcium ATPases. Moreover, gene loss events in wheat ancestors lead to the loss of a particular homoeolog of a gene in wheat. To elaborate the role of these wheat ATPases, qRT-PCR was performed. The results indicated that when plants are exposed to calcium stress, both P2A and P2B gene expression get enhanced. This further gives clues about the possible role of these ATPases in wheat in calcium management. These findings can be useful in future for genetic manipulations as well as in wheat genome annotation process.
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Affiliation(s)
- Roohi Aslam
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44000 Pakistan
| | | | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44000 Pakistan
| | - Nasar Virk
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44000 Pakistan
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14
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Evens NP, Buchner P, Williams LE, Hawkesford MJ. The role of ZIP transporters and group F bZIP transcription factors in the Zn-deficiency response of wheat (Triticum aestivum). Plant J 2017; 92:291-304. [PMID: 28771859 PMCID: PMC5656842 DOI: 10.1111/tpj.13655] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [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: 06/06/2017] [Revised: 07/25/2017] [Accepted: 07/28/2017] [Indexed: 05/12/2023]
Abstract
Understanding the molecular basis of zinc (Zn) uptake and transport in staple cereal crops is critical for improving both Zn content and tolerance to low-Zn soils. This study demonstrates the importance of group F bZIP transcription factors and ZIP transporters in responses to Zn deficiency in wheat (Triticum aestivum). Seven group F TabZIP genes and 14 ZIPs with homeologs were identified in hexaploid wheat. Promoter analysis revealed the presence of Zn-deficiency-response elements (ZDREs) in a number of the ZIPs. Functional complementation of the zrt1/zrt2 yeast mutant by TaZIP3, -6, -7, -9 and -13 supported an ability to transport Zn. Group F TabZIPs contain the group-defining cysteine-histidine-rich motifs, which are the predicted binding site of Zn2+ in the Zn-deficiency response. Conservation of these motifs varied between the TabZIPs suggesting that individual TabZIPs may have specific roles in the wheat Zn-homeostatic network. Increased expression in response to low Zn levels was observed for several of the wheat ZIPs and bZIPs; this varied temporally and spatially suggesting specific functions in the response mechanism. The ability of the group F TabZIPs to bind to specific ZDREs in the promoters of TaZIPs indicates a conserved mechanism in monocots and dicots in responding to Zn deficiency. In support of this, TabZIPF1-7DL and TabZIPF4-7AL afforded a strong level of rescue to the Arabidopsis hypersensitive bzip19 bzip23 double mutant under Zn deficiency. These results provide a greater understanding of Zn-homeostatic mechanisms in wheat, demonstrating an expanded repertoire of group F bZIP transcription factors, adding to the complexity of Zn homeostasis.
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Affiliation(s)
- Nicholas P. Evens
- Rothamsted ResearchWest CommonHarpenden, HertfordshireAL5 2JQUK
- Biological ScienceUniversity of SouthamptonLife Sciences Building 85, Highfield CampusSouthamptonSO17 1BJUK
| | - Peter Buchner
- Rothamsted ResearchWest CommonHarpenden, HertfordshireAL5 2JQUK
| | - Lorraine E. Williams
- Biological ScienceUniversity of SouthamptonLife Sciences Building 85, Highfield CampusSouthamptonSO17 1BJUK
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15
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Bennett AL, Williams LE, Ferguson MW, Hauck ML, Suter SE, Lanier CB, Hess PR. Canine acute leukaemia: 50 cases (1989-2014). Vet Comp Oncol 2016; 15:1101-1114. [PMID: 27402031 DOI: 10.1111/vco.12251] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 05/26/2016] [Accepted: 05/31/2016] [Indexed: 12/15/2022]
Abstract
Acute leukaemia (AL) is a bone marrow malignancy of hematopoietic progenitors that historically is poorly responsive to treatment. With the widespread adoption of dose-intense chemotherapy, more human patients attain long-term survivals, but whether comparable progress has been made in canine AL is unknown. To investigate this question, medical records from three academic veterinary hospitals were reviewed. Fifty dogs met the criteria for AL, having excess circulating or marrow blasts, a major cytopenia(s), and no substantial lymphadenopathy. Thirty-six dogs received cytotoxic chemotherapy; 23 achieved a complete or partial response for a median of 56 days (range, 9-218). With failure or relapse, 14 dogs were rescued. Median survival with treatment was poor at 55 days (range, 1-300). Untreated (n = 6) and palliatively-treated (n = 8) dogs lived a median of 7.5 days. Most dogs developed chemoresistance within weeks of initiating treatment, and consequently, survival times for AL remain disappointingly short.
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Affiliation(s)
- A L Bennett
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - L E Williams
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - M W Ferguson
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - M L Hauck
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - S E Suter
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - C B Lanier
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - P R Hess
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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16
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Burton JH, Venable RO, Vail DM, Williams LE, Clifford CA, Axiak-Bechtel SM, Avery AC, Thamm DH. Pulse-Administered Toceranib Phosphate Plus Lomustine for Treatment of Unresectable Mast Cell Tumors in Dogs. J Vet Intern Med 2015; 29:1098-104. [PMID: 26119008 PMCID: PMC4895362 DOI: 10.1111/jvim.13573] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/01/2015] [Accepted: 05/14/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Nonresectable mast cell tumors (MCT) in dogs remain a therapeutic challenge, and investigation of novel combination therapies is warranted. Intermittent administration of tyrosine kinase inhibitors (TKI) combined with cytotoxic chemotherapy may effectively chemosensitize canine MCT while decreasing cost and adverse effects associated with either agent administered as monotherapy. HYPOTHESIS/OBJECTIVES The primary study objectives were to (1) identify the maximally tolerated dose (MTD), (2) determine the objective response rate (ORR) and (3) describe the adverse event profile of pulse-administered toceranib phosphate (TOC) combined with lomustine. ANIMALS Forty-seven client-owned dogs with measurable MCT. METHODS Toceranib phosphate was given PO on days 1, 3 and 5 of a 21-day cycle at a target dosage of 2.75 mg/kg. Lomustine was given PO on day 3 of each cycle at a starting dosage of 50 mg/m(2) . All dogs were concurrently treated with diphenhydramine, omeprazole, and prednisone. RESULTS The MTD of lomustine was established at 50 mg/m(2) when combined with pulse-administered TOC; the dose-limiting toxicity was neutropenia. Forty-one dogs treated at the MTD were evaluable for outcome assessment. The ORR was 46% (4 complete response, 15 partial response) and the overall median progression-free survival (PFS) was 53 days (1 to >752 days). On multivariate analysis, variables significantly associated with improved PFS included response to treatment, absence of metastasis, and no previous chemotherapy. CONCLUSIONS AND CLINICAL IMPORTANCE Combined treatment with pulse-administered TOC and lomustine generally is well tolerated and may be a reasonable treatment option for dogs with unresectable or metastatic MCT.
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Affiliation(s)
- J H Burton
- Flint Animal Cancer Center, Department of Clinical Sciences, Colorado State University, Fort Collins, CO.,Department of Surgical and Radiological Sciences, University of California, Davis, Davis, CA
| | - R O Venable
- Flint Animal Cancer Center, Department of Clinical Sciences, Colorado State University, Fort Collins, CO.,Arizona Veterinary Oncology, Gilbert, AZ
| | - D M Vail
- School of Veterinary Medicine and the Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI
| | - L E Williams
- Department of Clinical Sciences, North Carolina State University, Raleigh, NC.,Veterinary Specialty Hospital of the Carolinas, Cary, NC
| | - C A Clifford
- Red Bank Veterinary Hospital, Tinton Falls, NJ.,Hope Veterinary Specialists, Malvern, PA
| | - S M Axiak-Bechtel
- Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO
| | - A C Avery
- Flint Animal Cancer Center, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO
| | - D H Thamm
- Flint Animal Cancer Center, Department of Clinical Sciences, Colorado State University, Fort Collins, CO
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17
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Blackford JU, Williams LE, Heckers S. Neural correlates of out-group bias predict social impairment in patients with schizophrenia. Schizophr Res 2015; 164:203-9. [PMID: 25864952 PMCID: PMC4512167 DOI: 10.1016/j.schres.2015.03.019] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 03/17/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Social impairments are a hallmark feature of schizophrenia and are a key predictor of functional disability. Deficits in social information processing likely underlie social impairment; however, this relationship is understudied. We previously demonstrated that patients with schizophrenia fail to habituate to neutral faces, providing evidence for an alteration in basic social information processing. It remains unknown whether patients with schizophrenia also show deficits in processing of more complex social information. Out-group bias provides an excellent opportunity to test complex social information processing because the bias requires basic face processing skills, the ability to discriminate between groups, as well as the ability to categorize oneself into a salient social group. METHODS Study participants were 23 patients with schizophrenia and 21 controls. Using functional magnetic resonance imaging, habituation of response to 120 s of repeated presentations of faces was assessed in participants who viewed either same-gender faces or opposite-gender faces. The interaction between face gender (same/opposite) and group was examined in three key regions: amygdala, hippocampus, and visual cortex. Social impairment was measured using the PANSS and correlations between social impairment and out-group effect (main effect of face type) were performed in patients. RESULTS Patients with schizophrenia had aberrant neural responses to opposite-gender faces (interaction, p<.05 corrected). Healthy controls showed an immediate heightened response to opposite-gender faces relative to same-gender faces; but in patients this effect was substantially delayed (~70s). In patients with schizophrenia, the out-group bias was significantly correlated with social impairment. Patients with no social impairment showed a heightened neural response to opposite-gender faces after 30s, whereas patients with mild-moderate social impairment failed to ever show a heightened response. CONCLUSION Alterations in neural responses during out-group processing predicted degree of social impairment in patients with schizophrenia; thus, neural responses to opposite-gender faces may provide a novel measure for studies of treatment response and disease outcome.
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Affiliation(s)
- JU Blackford
- Department of Psychiatry, Vanderbilt University School of Medicine, 1601 23 Avenue South, Nashville, TN 37212
| | - LE Williams
- Department of Psychiatry, University of Wisconsin-Madison, Wisconsin Psychiatric Institute & Clinics, 6001 Research Park Blvd., Madison, WI 53719
| | - S Heckers
- Department of Psychiatry, Vanderbilt University School of Medicine, 1601 23 Avenue South, Nashville, TN 37212
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18
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Kendziorek M, Barabasz A, Rudzka J, Tracz K, Mills RF, Williams LE, Antosiewicz DM. Approach to engineer tomato by expression of AtHMA4 to enhance Zn in the aerial parts. J Plant Physiol 2014; 171:1413-22. [PMID: 25046762 DOI: 10.1016/j.jplph.2014.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [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: 02/15/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 05/14/2023]
Abstract
The aim of this work was to assess the potential for using AtHMA4 to engineer enhanced efficiency of Zn translocation to shoots, and to increase the Zn concentration in aerial tissues of tomato. AtHMA4, a P1B-ATPase, encodes a Zn export protein known to be involved in the control of Zn root-to-shoot translocation. In this work, 35S::AtHMA4 was expressed in tomato (Lycopersicon esculentum var. Beta). Wild-type and transgenic plants were tested for Zn and Cd tolerance; Zn, Fe and Cd accumulation patterns, and for the expression of endogenous Zn/Fe-homeostasis genes. At 10μM Zn exposure, a higher Zn concentration was observed in leaves of AtHMA4-expressing lines compared to wild-type, which is promising in terms of Zn biofortification. AtHMA4 also transports Cd and at 0.25μM Cd the transgenic plants showed similar levels of this element in leaves to wild-type but lower levels in roots, therefore indicating a reduction of Cd uptake due to AtHMA4 expression. Expression of this transgene AtHMA4 also resulted in distinct changes in Fe accumulation in Zn-exposed plants, and Fe/Zn-accumulation in Cd-exposed plants, even though Fe is not a substrate for AtHMA4. Analysis of the transcript abundance of key Zn/Fe-homeostasis genes showed that the pattern was distinct for transgenic and wild-type plants. The reduction of Fe accumulation observed in AtHMA4-transformants was accompanied by up-regulation of Fe-deficiency marker genes (LeFER, LeFRO1, LeIRT1), whereas down-regulation was detected in plants with the status of Fe-sufficiency. Furthermore, results strongly suggest the importance of the up-regulation of LeCHLN in the roots of AtHMA4-expressing plants for efficient translocation of Zn to the shoots. Thus, the modifications of Zn/Fe/Cd translocation to aerial plant parts due to AtHMA4 expression are closely related to the alteration of the endogenous Zn-Fe-Cd cross-homeostasis network of tomato.
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Affiliation(s)
- Maria Kendziorek
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland
| | - Anna Barabasz
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland
| | - Justyna Rudzka
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland
| | - Katarzyna Tracz
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland
| | - Rebecca F Mills
- University of Southampton, Centre for Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Lorraine E Williams
- University of Southampton, Centre for Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Danuta Maria Antosiewicz
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland.
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Abstract
Physician associates (PAs) are a new profession to the UK. There has been no prior national assessment of the perspectives of doctors who work with PAs with regard to their role. Doctors who supervise PAs were surveyed in late 2012; respondents were found generally to be satisfied with the role of PAs and believed that the addition of the PA to the team benefited doctors and patients. Doctors reported that they have received positive feedback from patients about the role of PAs as well. Respondents believe that the current unregulated status of the profession impairs their ability to use their PA staff to their fullest potential.
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Affiliation(s)
| | - Tamara S Ritsema
- University of Nebraska Medical Center, Omaha, Nebraska, USA
- St George's University of London, London, UK
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Sperotto RA, Ricachenevsky FK, Williams LE, Vasconcelos MW, Menguer PK. From soil to seed: micronutrient movement into and within the plant. Front Plant Sci 2014; 5:438. [PMID: 25250035 PMCID: PMC4155779 DOI: 10.3389/fpls.2014.00438] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/15/2014] [Indexed: 05/18/2023]
Affiliation(s)
- Raul A. Sperotto
- Programa de Pós-Graduação em Biotecnologia, Centro de Ciências Biológicas e da Saúde, Centro Universitário UNIVATESLajeado, Brazil
- *Correspondence: ; ; ; ;
| | - Felipe K. Ricachenevsky
- Departamento de Botânica e Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
- *Correspondence: ; ; ; ;
| | - Lorraine E. Williams
- Centre for Biological Sciences, University of SouthamptonSouthampton, UK
- *Correspondence: ; ; ; ;
| | - Marta W. Vasconcelos
- Centro de Biotecnologia e Química Fina–Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica PortuguesaPorto, Portugal
- *Correspondence: ; ; ; ;
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Barabasz A, Wilkowska A, Tracz K, Ruszczyńska A, Bulska E, Mills RF, Williams LE, Antosiewicz DM. Expression of HvHMA2 in tobacco modifies Zn-Fe-Cd homeostasis. J Plant Physiol 2013; 170:1176-86. [PMID: 23664582 DOI: 10.1016/j.jplph.2013.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [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: 12/21/2012] [Revised: 03/21/2013] [Accepted: 03/24/2013] [Indexed: 05/20/2023]
Abstract
HvHMA2 is a plasma membrane P1B-ATPase from barley that functions in Zn/Cd root-to-shoot transport. To assess the usefulness of HvHMA2 for modifying the metal content in aerial plant parts, it was expressed in tobacco under the CaMV35S promoter. Transformation with HvHMA2 did not produce one unique pattern of Zn and Cd accumulation; instead it depended on external metal supply. Thus Zn and Cd root-to-shoot translocation was facilitated, but not at all applied Zn/Cd concentrations. Metal uptake was restricted in HvHMA2-transformed plants and the level in the shoot was not enhanced. It was shown that HvHMA2 localizes to the plasma membrane of tobacco cells, and overloads the apoplast with Zn, which could explain the overall decrease in metal uptake observed. Despite the lower levels in the shoot, HvHMA2 transformants showed increased Zn sensitivity. Moreover, introduction of HvHMA2 into tobacco interfered with Fe metabolism and Fe accumulation was modified in HvHMA2-transformants in a Zn- and Cd-concentration dependent manner. The results indicate that ectopic expression of the export protein HvHMA2 in tobacco interferes with tobacco metal Zn-Cd-Fe cross-homeostasis, inducing internal mechanisms regulating metal uptake and tolerance.
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Affiliation(s)
- Anna Barabasz
- Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa Street 1, 02-096 Warszawa, Poland
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22
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Menguer PK, Farthing E, Peaston KA, Ricachenevsky FK, Fett JP, Williams LE. Functional analysis of the rice vacuolar zinc transporter OsMTP1. J Exp Bot 2013; 64:2871-83. [PMID: 23761487 PMCID: PMC3697945 DOI: 10.1093/jxb/ert136] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Heavy metal homeostasis is maintained in plant cells by specialized transporters which compartmentalize or efflux metal ions, maintaining cytosolic concentrations within a narrow range. OsMTP1 is a member of the cation diffusion facilitator (CDF)/metal tolerance protein (MTP) family of metal cation transporters in Oryza sativa, which is closely related to Arabidopsis thaliana MTP1. Functional complementation of the Arabidopsis T-DNA insertion mutant mtp1-1 demonstrates that OsMTP1 transports Zn in planta and localizes at the tonoplast. When heterologously expressed in the yeast mutant zrc1 cot1, OsMTP1 complemented its Zn hypersensitivity and was also localized to the vacuole. OsMTP1 alleviated, to some extent, the Co sensitivity of this mutant, rescued the Fe hypersensitivity of the ccc1 mutant at low Fe concentrations, and restored growth of the Cd-hypersensitive mutant ycf1 at low Cd concentrations. These results suggest that OsMTP1 transports Zn but also Co, Fe, and Cd, possibly with lower affinity. Site-directed mutagenesis studies revealed two substitutions in OsMTP1 that alter the transport function of this protein. OsMTP1 harbouring a substitution of Leu82 to a phenylalanine can still transport low levels of Zn, with an enhanced affinity for Fe and Co, and a gain of function for Mn. A substitution of His90 with an aspartic acid completely abolishes Zn transport but improves Fe transport in OsMTP1. These amino acid residues are important in determining substrate specificity and may be a starting point for refining transporter activity in possible biotechnological applications, such as biofortification and phytoremediation.
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Affiliation(s)
- Paloma K. Menguer
- Centre for Biological Science, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton SO17 1B, UK
- Departamento de Botânica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91501–970, Brazil
| | - Emily Farthing
- Centre for Biological Science, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton SO17 1B, UK
| | - Kerry A. Peaston
- Centre for Biological Science, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton SO17 1B, UK
| | - Felipe Klein Ricachenevsky
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, PO Box 15005, Porto Alegre, 91501–970, Brazil
| | - Janette Palma Fett
- Departamento de Botânica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91501–970, Brazil
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, PO Box 15005, Porto Alegre, 91501–970, Brazil
| | - Lorraine E. Williams
- Centre for Biological Science, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton SO17 1B, UK
- *To whom correspondence should be addressed. E-mail:
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Ricachenevsky FK, Menguer PK, Sperotto RA, Williams LE, Fett JP. Roles of plant metal tolerance proteins (MTP) in metal storage and potential use in biofortification strategies. Front Plant Sci 2013; 4:144. [PMID: 23717323 PMCID: PMC3653063 DOI: 10.3389/fpls.2013.00144] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/26/2013] [Indexed: 05/05/2023]
Abstract
Zinc (Zn) is an essential micronutrient for plants, playing catalytic or structural roles in enzymes, transcription factors, ribosomes, and membranes. In humans, Zn deficiency is the second most common mineral nutritional disorder, affecting around 30% of the world's population. People living in poverty usually have diets based on milled cereals, which contain low Zn concentrations. Biofortification of crops is an attractive cost-effective solution for low mineral dietary intake. In order to increase the amounts of bioavailable Zn in crop edible portions, it is necessary to understand how plants take up, distribute, and store Zn within their tissues, as well as to characterize potential candidate genes for biotechnological manipulation. The metal tolerance proteins (MTP) were described as metal efflux transporters from the cytoplasm, transporting mainly Zn(2+) but also Mn(2+), Fe(2+), Cd(2+), Co(2+), and Ni(2+). Substrate specificity appears to be conserved in phylogenetically related proteins. MTPs characterized so far in plants have a role in general Zn homeostasis and tolerance to Zn excess; in tolerance to excess Mn and also in the response to iron (Fe) deficiency. More recently, the first MTPs in crop species have been functionally characterized. In Zn hyperaccumulator plants, the MTP1 protein is related to hypertolerance to elevated Zn concentrations. Here, we review the current knowledge on this protein family, as well as biochemical functions and physiological roles of MTP transporters in Zn hyperaccumulators and non-accumulators. The potential applications of MTP transporters in biofortification efforts are discussed.
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Affiliation(s)
| | - Paloma K. Menguer
- Departamento de Botânica, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Raul A. Sperotto
- Centro de Ciências Biológicas e da Saúde, Programa de Pós-Graduação em Biotecnologia (PPGBiotec), Centro Universitário UNIVATESLajeado, Brazil
| | | | - Janette P. Fett
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
- Departamento de Botânica, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
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24
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Blomquist GE, Williams LE. Quantitative genetics of costly neonatal sexual size dimorphism in squirrel monkeys (Saimiri boliviensis). J Evol Biol 2013; 26:756-65. [PMID: 23437981 PMCID: PMC4646609 DOI: 10.1111/jeb.12096] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 11/20/2012] [Indexed: 01/25/2023]
Abstract
Offspring size is often an intimate link between the fitness of parents and offspring. Among mammals, neonate mass is also related to adult levels of dimorphism and intrasexual competitive mating. We describe the sex-specific genetic architecture of neonate mass in captive squirrel monkeys (Saimiri boliviensis), a small Neotropical primate. Best fitting quantitative genetic models show strong maternal genetic effects with little difference between sexes offering limited opportunity for neonatal dimorphism to respond to observed or hypothetical selection. Heritabilities that are approximately zero also imply it is unlikely that neonatal dimorphism can evolve as a correlated response to selection on adult size. However, male mass is also more dependent on maternal condition (age and parity) making dimorphism plastic. Finally, we hypothesize that large maternal genetic effects reflect income breeding and tightly synchronized seasonal reproduction in squirrel monkeys, both of which require strong maternal control of offspring growth and timing of birth.
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Affiliation(s)
- G E Blomquist
- Department of Anthropology, University of Missouri, Columbia, MO 65211, USA.
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25
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Hopper LM, Holmes AN, Williams LE, Brosnan SF. Dissecting the mechanisms of squirrel monkey (Saimiri boliviensis) social learning. PeerJ 2013; 1:e13. [PMID: 23638347 PMCID: PMC3628937 DOI: 10.7717/peerj.13] [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] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 01/02/2013] [Indexed: 11/24/2022] Open
Abstract
Although the social learning abilities of monkeys have been well documented, this research has only focused on a few species. Furthermore, of those that also incorporated dissections of social learning mechanisms, the majority studied either capuchins (Cebus apella) or marmosets (Callithrix jacchus). To gain a broader understanding of how monkeys gain new skills, we tested squirrel monkeys (Saimiri boliviensis) which have never been studied in tests of social learning mechanisms. To determine whether S. boliviensis can socially learn, we ran "open diffusion" tests with monkeys housed in two social groups (N = 23). Over the course of 10 20-min sessions, the monkeys in each group observed a trained group member retrieving a mealworm from a bidirectional task (the "Slide-box"). Two thirds (67%) of these monkeys both learned how to operate the Slide-box and they also moved the door significantly more times in the direction modeled by the trained demonstrator than the alternative direction. To tease apart the underlying social learning mechanisms we ran a series of three control conditions with 35 squirrel monkeys that had no previous experience with the Slide-box. The first replicated the experimental open diffusion sessions but without the inclusion of a trained model, the second was a no-information control with dyads of monkeys, and the third was a 'ghost' display shown to individual monkeys. The first two controls tested for the importance of social support (mere presence effect) and the ghost display showed the affordances of the task to the monkeys. The monkeys showed a certain level of success in the group control (54% of subjects solved the task on one or more occasions) and paired controls (28% were successful) but none were successful in the ghost control. We propose that the squirrel monkeys' learning, observed in the experimental open diffusion tests, can be best described by a combination of social learning mechanisms in concert; in this case, those mechanisms are most likely object movement reenactment and social facilitation. We discuss the interplay of these mechanisms and how they related to learning shown by other primate species.
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Affiliation(s)
- LM Hopper
- Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, USA
- Language Research Center, Georgia State University, Atlanta, GA, USA
| | - AN Holmes
- Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA
| | - LE Williams
- Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA
| | - SF Brosnan
- Language Research Center, Georgia State University, Atlanta, GA, USA
- Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA
- Department of Psychology & Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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26
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Mikkelsen MD, Pedas P, Schiller M, Vincze E, Mills RF, Borg S, Møller A, Schjoerring JK, Williams LE, Baekgaard L, Holm PB, Palmgren MG. Barley HvHMA1 is a heavy metal pump involved in mobilizing organellar Zn and Cu and plays a role in metal loading into grains. PLoS One 2012; 7:e49027. [PMID: 23155447 PMCID: PMC3498361 DOI: 10.1371/journal.pone.0049027] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/03/2012] [Indexed: 12/11/2022] Open
Abstract
Heavy metal transporters belonging to the P(1B)-ATPase subfamily of P-type ATPases are key players in cellular heavy metal homeostasis. Heavy metal transporters belonging to the P(1B)-ATPase subfamily of P-type ATPases are key players in cellular heavy metal homeostasis. In this study we investigated the properties of HvHMA1, which is a barley orthologue of Arabidopsis thaliana AtHMA1 localized to the chloroplast envelope. HvHMA1 was localized to the periphery of chloroplast of leaves and in intracellular compartments of grain aleurone cells. HvHMA1 expression was significantly higher in grains compared to leaves. In leaves, HvHMA1 expression was moderately induced by Zn deficiency, but reduced by toxic levels of Zn, Cu and Cd. Isolated barley chloroplasts exported Zn and Cu when supplied with Mg-ATP and this transport was inhibited by the AtHMA1 inhibitor thapsigargin. Down-regulation of HvHMA1 by RNA interference did not have an effect on foliar Zn and Cu contents but resulted in a significant increase in grain Zn and Cu content. Heterologous expression of HvHMA1 in heavy metal-sensitive yeast strains increased their sensitivity to Zn, but also to Cu, Co, Cd, Ca, Mn, and Fe. Based on these results, we suggest that HvHMA1 is a broad-specificity exporter of metals from chloroplasts and serve as a scavenging mechanism for mobilizing plastid Zn and Cu when cells become deficient in these elements. In grains, HvHMA1 might be involved in mobilizing Zn and Cu from the aleurone cells during grain filling and germination.
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Affiliation(s)
- Maria Dalgaard Mikkelsen
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Pai Pedas
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Michaela Schiller
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Eva Vincze
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Rebecca F. Mills
- Centre for Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Søren Borg
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Annette Møller
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jan K. Schjoerring
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Lorraine E. Williams
- Centre for Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Lone Baekgaard
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Preben Bach Holm
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Michael G. Palmgren
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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Jaffé FW, Freschet GEC, Valdes BM, Runions J, Terry MJ, Williams LE. G protein-coupled receptor-type G proteins are required for light-dependent seedling growth and fertility in Arabidopsis. Plant Cell 2012; 24:3649-68. [PMID: 23001037 PMCID: PMC3480293 DOI: 10.1105/tpc.112.098681] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 07/13/2012] [Accepted: 08/28/2012] [Indexed: 05/20/2023]
Abstract
G protein-coupled receptor-type G proteins (GTGs) are highly conserved membrane proteins in plants, animals, and fungi that have eight to nine predicted transmembrane domains. They have been classified as G protein-coupled receptor-type G proteins that function as abscisic acid (ABA) receptors in Arabidopsis thaliana. We cloned Arabidopsis GTG1 and GTG2 and isolated new T-DNA insertion alleles of GTG1 and GTG2 in both Wassilewskija and Columbia backgrounds. These gtg1 gtg2 double mutants show defects in fertility, hypocotyl and root growth, and responses to light and sugars. Histological studies of shoot tissue reveal cellular distortions that are particularly evident in the epidermal layer. Stable expression of GTG1(pro):GTG1-GFP (for green fluorescent protein) in Arabidopsis and transient expression in tobacco (Nicotiana tabacum) indicate that GTG1 is localized primarily to Golgi bodies and to the endoplasmic reticulum. Microarray analysis comparing gene expression profiles in the wild type and double mutant revealed differences in expression of genes important for cell wall function, hormone response, and amino acid metabolism. The double mutants isolated here respond normally to ABA in seed germination assays, root growth inhibition, and gene expression analysis. These results are inconsistent with their proposed role as ABA receptors but demonstrate that GTGs are fundamentally important for plant growth and development.
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Affiliation(s)
- Felix W. Jaffé
- Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Gian-Enrico C. Freschet
- Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Billy M. Valdes
- Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - John Runions
- Oxford Brookes University, Department of Biological and Medical Sciences, Oxford OX3 0BP, United Kingdom
| | - Matthew J. Terry
- Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Lorraine E. Williams
- Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
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Mills RF, Peaston KA, Runions J, Williams LE. HvHMA2, a P(1B)-ATPase from barley, is highly conserved among cereals and functions in Zn and Cd transport. PLoS One 2012; 7:e42640. [PMID: 22880063 PMCID: PMC3411818 DOI: 10.1371/journal.pone.0042640] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/11/2012] [Indexed: 11/21/2022] Open
Abstract
Manipulation of crops to improve their nutritional value (biofortification) and optimisation of plants for removal of toxic metals from contaminated soils (phytoremediation) are major goals. Identification of membrane transporters with roles in zinc and cadmium transport would be useful for both aspects. The P1B-ATPases play important roles in heavy metal allocation and detoxification in Arabidopsis and it is now important to elucidate their roles in monocots. We identified nine P1B-ATPases in barley and this study focuses on the functional characterization of HvHMA2, providing evidence for its role in heavy metal transport. HvHMA2 was cloned using information from EST analysis and 5′ RACE. It possesses the conserved aspartate that is phosphorylated during the reaction cycle of P-type pumps and has motifs and key residues characteristic of P1B-ATPases, falling into the P1B-2 subclass. Homologous sequences occur in three major sub-families of the Poaceae (Gramineae). Heterologous expression in Saccharomyces cerevisiae demonstrates that HvHMA2 functions as a Zn and Cd pump. Mutagenesis studies show that proposed cation coordination sites of the P1B-2 pumps are crucial for the metal responses conferred by HvHMA2 in yeast. HvHMA2 expression suppresses the Zn-deficient phenotype of the Arabidopsis hma2hma4 mutant indicating that HvHMA2 functions as a Zn pump in planta and could play a role in root to shoot Zn transport. When expressed in Arabidopsis, HvHMA2 localises predominantly to the plasma membrane.
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Affiliation(s)
- Rebecca F. Mills
- Centre for Biological Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
| | - Kerry A. Peaston
- Centre for Biological Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
| | - John Runions
- Oxford Brookes University, School of Life Sciences, Oxford, United Kingdom
| | - Lorraine E. Williams
- Centre for Biological Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
- * E-mail:
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29
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Gould N, Thorpe MR, Pritchard J, Christeller JT, Williams LE, Roeb G, Schurr U, Minchin PEH. AtSUC2 has a role for sucrose retrieval along the phloem pathway: evidence from carbon-11 tracer studies. Plant Sci 2012; 188-189:97-101. [PMID: 22525249 DOI: 10.1016/j.plantsci.2011.12.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 12/22/2011] [Accepted: 12/22/2011] [Indexed: 05/31/2023]
Abstract
The location of the phloem within a plant, and its vulnerability to disruption, make it a difficult tissue to study and therefore non-invasive studies of phloem functionality are important. Here we compare, phloem transport, measured non-invasively, in wild type Arabidopsis thaliana, and transposon-insertion mutants for AtSUC1 or AtSUC2, giving in vivo information on the importance of these sucrose transporters for phloem transport. The suc2 mutant showed an increase in both phloem leakage and transport time, consistent with reduced sucrose uptake into both transport and collection phloem. The results are consistent with the AtSUC2 transporter being important for retrieval of leaked sucrose in the transport phloem of Arabidopsis. There was no difference in phloem transport properties between the wild type and the suc1 mutants, implying that the AtSUC1 transporter does not play a significant role within the transport phloem of Arabidopsis under the conditions of our study.
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Affiliation(s)
- N Gould
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 3230, Waikato Mail Centre, Hamilton 3240, New Zealand.
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30
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Abstract
There is little information regarding the presentation, biologic behaviour, treatment and prognosis in cats with chronic lymphocytic leukaemia (CLL), and further investigation is needed to characterize this disease in cats. The goal of this study was to describe the clinical presentation, response to treatment and prognosis of feline CLL. A multi-institutional retrospective study of 18 cats diagnosed with CLL between 2000 and 2010 was performed. CLL was defined as the presence of a mature lymphocytosis (>9000 lymphocytes µL(-1) ) and confirmation of an immunophenotypically monomorphic or clonal lymphoid population. Each patient was required to also have at least one of the two following criteria: (1) concurrent cytopenia of at least one cell line and/or (2) >15% mature lymphocytes in the bone marrow. Data on signalment, history, clinical signs, clinicopathologic features and response to treatment were reviewed. Median age of the cats at initial presentation was 12.5 years (range: 5-20 years). The most common presenting complaint was chronic weight loss, which was present in 8/18 (44%) cats. Sixteen of 18 (89%) cats were treated with chlorambucil and prednisolone; four of these cats also received vincristine. Two (11%) cats were treated with multi-agent injectable chemotherapy (L-CHOP, l-asparaginase, cyclophosphamide, doxorubicin, vincristine, prednisolone). Eighty-eight percent of cats evaluable for response achieved a complete (nine cats) or partial (six cats) remission. Median overall remission was 15.7 months (range: 1.3-22.8 months). The median overall survival in the 17 cats with follow-up data was 14.4 months (range: 0.9-25.3 months). Results of this study suggest that CLL affects older-aged cats and responds favourably to treatment with oral chlorambucil and prednisolone.
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Affiliation(s)
- M W Campbell
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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Power ML, Williams LE, Gibson SV, Schulkin J, Helfers J, Zorrilla EP. Pattern of maternal circulating CRH in laboratory-housed squirrel and owl monkeys. Am J Primatol 2010; 72:1004-12. [PMID: 20872786 PMCID: PMC2947327 DOI: 10.1002/ajp.20850] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The anthropoid primate placenta appears to be unique in producing corticotropin-releasing hormone (CRH). Placental CRH is involved in an endocrine circuit key to the production of estrogens during pregnancy. CRH induces cortisol production by the maternal and fetal adrenal glands, leading to further placental CRH production. CRH also stimulates the fetal adrenal glands to produce dehydroepiandrostendione sulfate (DHEAS), which the placenta converts into estrogens. There are at least two patterns of maternal circulating CRH across gestation among anthropoids. Monkeys examined to date (Papio and Callithrix) have an early-to-mid gestational peak of circulating CRH, followed by a steady decline to a plateau level, with a possible rise near parturition. In contrast, humans and great apes have an exponential rise in circulating CRH peaking at parturition. To further document and compare patterns of maternal circulating CRH in anthropoid primates, we collected monthly blood samples from 14 squirrel monkeys (Saimiri boliviensis) and ten owl monkeys (Aotus nancymaae) during pregnancy. CRH immunoreactivity was measured from extracted plasma by using solid-phase radioimmunoassay. Both squirrel and owl monkeys displayed a mid-gestational peak in circulating CRH: days 45-65 of the 152-day gestation for squirrel monkeys (mean±SEM CRH=2,694±276 pg/ml) and days 60-80 of the 133-day gestation for owl monkeys (9,871±974 pg/ml). In squirrel monkeys, circulating CRH declined to 36% of mean peak value by 2 weeks before parturition and then appeared to increase; the best model for circulating CRH over gestation in squirrel monkeys was a cubic function, similar to previous results for baboons and marmosets. In owl monkeys, circulating CRH appeared to reach plateau with no subsequent significant decline approaching parturition, although a cubic function was the best fit. This study provides additional evidence for a mid-gestational peak of maternal circulating CRH in ancestral anthropoids that has been lost in the hominoid lineage.
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Affiliation(s)
- M L Power
- Conservation Ecology Center, Smithsonian National Zoological Park, Washington, District of Columbia, USA.
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Mills RF, Valdes B, Duke M, Peaston KA, Lahner B, Salt DE, Williams LE. Functional significance of AtHMA4 C-terminal domain in planta. PLoS One 2010; 5:e13388. [PMID: 20975991 PMCID: PMC2958113 DOI: 10.1371/journal.pone.0013388] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [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: 07/16/2010] [Accepted: 09/07/2010] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Enhancing the upward translocation of heavy metals such as Zn from root to shoot through genetic engineering has potential for biofortification and phytoremediation. This study examined the contribution of the heavy metal-transporting ATPase, AtHMA4, to the shoot ionomic profile of soil-grown plants, and investigated the importance of the C-terminal domain in the functioning of this transporter. PRINCIPAL FINDINGS The Arabidopsis hma2 hma4 mutant has a stunted phenotype and a distinctive ionomic profile, with low shoot levels of Zn, Cd, Co, K and Rb, and high shoot Cu. Expression of AtHMA4 (AtHMA4-FL) under the CaMV-35S promoter partially rescued the stunted phenotype of hma2 hma4; rosette diameter returned to wild-type levels in the majority of lines and bolts were also produced, although the average bolt height was not restored completely. AtHMA4-FL expression rescued Co, K, Rb and Cu to wild-type levels, and partially returned Cd and Zn levels (83% and 28% of wild type respectively). In contrast, expression of AtHMA4-trunc (without the C-terminal region) in hma2 hma4 only partially restored the rosette diameter in two of five lines and bolt production was not rescued. There was no significant effect on the shoot ionomic profile, apart from Cd, which was increased to 41% of wild-type levels. When the AtHMA4 C-terminal domain (AtHMA4-C-term) was expressed in hma2 hma4 it had no marked effect. When expressed in yeast, AtHMA4-C-term and AtHMA4-trunc conferred greater Cd and Zn tolerance than AtHMA4-FL. CONCLUSION The ionome of the hma2 hma4 mutant differs markedly from wt plants. The functional relevance of domains of AtHMA4 in planta can be explored by complementing this mutant. AtHMA4-FL is more effective in restoring shoot metal accumulation in this mutant than a C-terminally truncated version of the pump, indicating that the C-terminal domain is important in the functioning of AtHMA4 in planta.
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Affiliation(s)
- Rebecca F. Mills
- School of Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Billy Valdes
- School of Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Michael Duke
- School of Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Kerry A. Peaston
- School of Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Brett Lahner
- Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, Illinois, United States of America
| | - David E. Salt
- Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, Illinois, United States of America
| | - Lorraine E. Williams
- School of Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
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Baekgaard L, Mikkelsen MD, Sørensen DM, Hegelund JN, Persson DP, Mills RF, Yang Z, Husted S, Andersen JP, Buch-Pedersen MJ, Schjoerring JK, Williams LE, Palmgren MG. A combined zinc/cadmium sensor and zinc/cadmium export regulator in a heavy metal pump. J Biol Chem 2010; 285:31243-52. [PMID: 20650903 DOI: 10.1074/jbc.m110.111260] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Heavy metal pumps (P1B-ATPases) are important for cellular heavy metal homeostasis. AtHMA4, an Arabidopsis thaliana heavy metal pump of importance for plant Zn(2+) nutrition, has an extended C-terminal domain containing 13 cysteine pairs and a terminal stretch of 11 histidines. Using a novel size-exclusion chromatography, inductively coupled plasma mass spectrometry approach we report that the C-terminal domain of AtHMA4 is a high affinity Zn(2+) and Cd(2+) chelator with capacity to bind 10 Zn(2+) ions per C terminus. When AtHMA4 is expressed in a Zn(2+)-sensitive zrc1 cot1 yeast strain, sequential removal of the histidine stretch and the cysteine pairs confers a gradual increase in Zn(2+) and Cd(2+) tolerance and lowered Zn(2+) and Cd(2+) content of transformed yeast cells. We conclude that the C-terminal domain of AtHMA4 serves a dual role as Zn(2+) and Cd(2+) chelator (sensor) and as a regulator of the efficiency of Zn(2+) and Cd(2+) export. The identification of a post-translational handle on Zn(2+) and Cd(2+) transport efficiency opens new perspectives for regulation of Zn(2+) nutrition and tolerance in eukaryotes.
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Affiliation(s)
- Lone Baekgaard
- Department of Plant Biology and Biotechnology, Centre for Membrane Pumps in Cells and Disease, PUMPKIN, Danish National Research Foundation, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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McGeoch PD, Williams LE, Song T, Lee RR, Huang M, Ramachandran VS. Post-stroke tactile allodynia and its modulation by vestibular stimulation: a MEG case study. Acta Neurol Scand 2009; 119:404-9. [PMID: 18853944 DOI: 10.1111/j.1600-0404.2008.01106.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [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: 11/28/2022]
Abstract
BACKGROUND There is behavioural evidence that caloric vestibular stimulation (CVS) can alleviate central pain. Several such patients have also noted that it reduces tactile allodynia, an especially ill-understood phenomenon in these patients. AIMS OF THE STUDY The first aim is to use magnetoencephalography (MEG) to study neural activity associated with tactile allodynia in central post-stroke pain (CPSP). The second is to assess how this would be affected, if at all, by CVS. The third is to assess the ability of the VESTAL solution for MEG to detect anterior cingulate activation. METHODS A 58-year-old woman with CPSP, and marked unilateral tactile allodynia, participated in a MEG study with imaging pre- and post-CVS. RESULTS Tactile simulation within the patient's allodynic area resulted in contralateral activation of the primary motor and anterior cingulate cortices, which had normalized 24 h post-CVS. CONCLUSIONS We suggest that the unexpected primary motor cortex activation in response to light touch in the allodynic area arises from inappropriate activation of a normal mechanism, which may occur when a threat to homeostasis is present, to lower motor thresholds and allow for more rapid performance of corrective actions. We propose this may be mediated by the interoceptive cortex in the dorsal posterior insula.
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Affiliation(s)
- P D McGeoch
- Center for Brain and Cognition, University of California, San Diego, CA 92093-0109, USA.
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Abstract
BACKGROUND Similarities in human and canine renal cell carcinoma (RCC) epidemiology and biologic behavior suggest that molecular mechanisms of tumorigenesis may be similar in both species. Approximately 75% of RCC in people are of the clear cell subtype, up to 85% of which are associated with mutation of the von Hippel-Lindau (VHL) gene. The canine VHL coding deoxyribonucleic acid (DNA) shares 90% identity with the human VHL gene. OBJECTIVE To determine whether or not RCC in dogs are associated with VHL mutations, and if so determine the prevalence, type, and location of these mutations. ANIMALS Thirteen dogs with RCC, 2 dogs with primary renal sarcomas, and 10 dogs without neoplastic kidney disease. METHODS DNA was extracted from paraffin-embedded RCC tissue; DNA extracts from paraffin-embedded and snap-frozen nonneoplastic canine kidneys and canine whole blood were used as negative controls. Polymerase chain reaction and sequencing of the 3 VHL exons was performed, and results compared with the accessioned canine sequence. RESULTS All VHL exons were amplified from 9 of 13 canine RCC samples, both renal sarcomas, 8 of 10 nonneoplastic kidney samples, and canine whole blood; only exon 2 could be amplified from 2 RCC samples. Mutations were not identified in any exons. A maximal prevalence of 33.6% for VHL mutations in canine RCC was determined. CONCLUSION AND CLINICAL IMPORTANCE Although similarities between canine and human RCC merit further investigation of the dog as a model for some subtypes of renal tumors, the lower prevalence of VHL mutations suggests that oncogenesis in these 2 species differs.
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Affiliation(s)
- B M Pressler
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
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McGeoch PD, Williams LE, Lee RR, Ramachandran VS. Behavioural evidence for vestibular stimulation as a treatment for central post-stroke pain. J Neurol Neurosurg Psychiatry 2008; 79:1298-301. [PMID: 18550629 DOI: 10.1136/jnnp.2008.146738] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Central post-stroke pain (CPSP) is often resistant to treatment. We have previously proposed that caloric vestibular stimulation might alleviate it. METHODS We conducted a single blind placebo controlled investigational study of caloric vestibular stimulation (CVS) in nine patients with CPSP. Participants rated their pain levels before and after the procedure on a 10 point scale. RESULTS We found a significant immediate treatment effect of the cold water caloric stimulation with an average pain reduction of 2.58 points (SEM 0.52) for the experimental condition compared with 0.54 points (SEM 0.49) for the placebo conditions. CONCLUSIONS Participants who responded best to CVS had suffered strokes that spared and permitted activation of the dominant parieto-insular vestibular cortex (PIVC), which is known to be located in the non-dominant hemisphere. These findings tie in closely with the thermosensory disinhibition hypothesis for central pain, which leads us to propose that vestibular stimulation may alleviate CPSP from cross activation between the PIVC and the thermosensory cortex in the adjacent dorsal posterior insula. Alternatively, if one views vestibular function and thermoregulation as part of a larger interoceptive system that exists to maintain homeostasis, then it is possible they share a common integrative mechanism in the brainstem, which may act to reset the balance in central pain.
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Affiliation(s)
- P D McGeoch
- Centre for Brain and Cognition, University of California, San Diego, La Jolla, CA 92093-0109, USA.
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Palmgren MG, Clemens S, Williams LE, Krämer U, Borg S, Schjørring JK, Sanders D. Zinc biofortification of cereals: problems and solutions. Trends Plant Sci 2008; 13:464-73. [PMID: 18701340 DOI: 10.1016/j.tplants.2008.06.005] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 06/12/2008] [Accepted: 06/17/2008] [Indexed: 05/20/2023]
Abstract
The goal of biofortification is to develop plants that have an increased content of bioavailable nutrients in their edible parts. Cereals serve as the main staple food for a large proportion of the world population but have the shortcoming, from a nutrition perspective, of being low in zinc and other essential nutrients. Major bottlenecks in plant biofortification appear to be the root-shoot barrier and--in cereals--the process of grain filling. New findings demonstrate that the root-shoot distribution of zinc is controlled mainly by heavy metal transporting P1B-ATPases and the metal tolerance protein (MTP) family. A greater understanding of zinc transport is important to improve crop quality and also to help alleviate accumulation of any toxic metals.
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Affiliation(s)
- Michael G Palmgren
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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Mills RF, Doherty ML, López-Marqués RL, Weimar T, Dupree P, Palmgren MG, Pittman JK, Williams LE. ECA3, a Golgi-localized P2A-type ATPase, plays a crucial role in manganese nutrition in Arabidopsis. Plant Physiol 2008; 146:116-28. [PMID: 18024560 PMCID: PMC2230566 DOI: 10.1104/pp.107.110817] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Accepted: 11/11/2007] [Indexed: 05/18/2023]
Abstract
Calcium (Ca) and manganese (Mn) are essential nutrients required for normal plant growth and development, and transport processes play a key role in regulating their cellular levels. Arabidopsis (Arabidopsis thaliana) contains four P(2A)-type ATPase genes, AtECA1 to AtECA4, which are expressed in all major organs of Arabidopsis. To elucidate the physiological role of AtECA2 and AtECA3 in Arabidopsis, several independent T-DNA insertion mutant alleles were isolated. When grown on medium lacking Mn, eca3 mutants, but not eca2 mutants, displayed a striking difference from wild-type plants. After approximately 8 to 9 d on this medium, eca3 mutants became chlorotic, and root and shoot growth were strongly inhibited compared to wild-type plants. These severe deficiency symptoms were suppressed by low levels of Mn, indicating a crucial role for ECA3 in Mn nutrition in Arabidopsis. eca3 mutants were also more sensitive than wild-type plants and eca2 mutants on medium lacking Ca; however, the differences were not so striking because in this case all plants were severely affected. ECA3 partially restored the growth defect on high Mn of the yeast (Saccharomyces cerevisiae) pmr1 mutant, which is defective in a Golgi Ca/Mn pump (PMR1), and the yeast K616 mutant (Deltapmc1 Deltapmr1 Deltacnb1), defective in Golgi and vacuolar Ca/Mn pumps. ECA3 also rescued the growth defect of K616 on low Ca. Promoter:beta-glucuronidase studies show that ECA3 is expressed in a range of tissues and cells, including primary root tips, root vascular tissue, hydathodes, and guard cells. When transiently expressed in Nicotiana tabacum, an ECA3-yellow fluorescent protein fusion protein showed overlapping expression with the Golgi protein GONST1. We propose that ECA3 is important for Mn and Ca homeostasis, possibly functioning in the transport of these ions into the Golgi. ECA3 is the first P-type ATPase to be identified in plants that is required under Mn-deficient conditions.
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Affiliation(s)
- Rebecca F Mills
- School of Biological Sciences, University of Southampton, Southampton, UK
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Johnston DW, Chapla ME, Williams LE, Matthila DK. Identification of humpback whale Megaptera novaeangliae wintering habitat in the Northwestern Hawaiian Islands using spatial habitat modeling. ENDANGER SPECIES RES 2007. [DOI: 10.3354/esr00049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Fotopoulos V, Holmes R, Hall JL, Williams LE. Isolation, cloning and expression analysis of EcPMA1, a putative plasma membrane H+ -ATPase transporter gene from the biotrophic pathogenic fungus Erysiphe cichoracearum. ACTA ACUST UNITED AC 2005; 110:28-37. [PMID: 16431274 DOI: 10.1016/j.mycres.2005.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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: 05/30/2005] [Revised: 08/15/2005] [Accepted: 08/30/2005] [Indexed: 11/26/2022]
Abstract
Little is known at the molecular level about the transporters involved in nutrient transfer in the plant/powdery mildew interaction. A PCR-based approach was used to identify and isolate a partial-length cDNA coding for an isoform of the plasma membrane H+ -ATPase (EcPMA1) in the biotrophic pathogenic fungus Erysiphe cichoracearum. Southern analysis suggests that EcPMA1 exists as a single-copy gene. Sequence analysis indicated a high similarity of EcPMA1 to other fungal H+ -ATPases. Expression of EcPMA1 increases in infected Arabidopsis leaves as the disease progresses, correlating with the growth of the pathogen.
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Affiliation(s)
- Vasileios Fotopoulos
- School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, UK
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Williams LE, Mills RF. P(1B)-ATPases--an ancient family of transition metal pumps with diverse functions in plants. Trends Plant Sci 2005; 10:491-502. [PMID: 16154798 DOI: 10.1016/j.tplants.2005.08.008] [Citation(s) in RCA: 237] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 08/04/2005] [Accepted: 08/26/2005] [Indexed: 05/04/2023]
Abstract
P(1B)-ATPases form a distinct evolutionary sub-family of P-type ATPases, transporting transition metals such as Cu, Zn, Cd, Pb and Co across membranes in a wide range of organisms, including plants. Structurally they are distinct from other P-types, possessing eight transmembrane helices, a CPx/SPC motif in transmembrane domain six, and putative transition metal-binding domains at the N- and/or C-termini. Arabidopsis has eight P(1B)-ATPases (AtHMA1-AtHMA8), which differ in their structure, function and regulation. They perform a variety of important physiological tasks relating to transition metal transport and homeostasis. The crucial roles of plant P(1B)-ATPases in micronutrient nutrition, delivery of essential metals to target proteins, and toxic metal detoxification are discussed.
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Affiliation(s)
- Lorraine E Williams
- School of Biological Sciences, University of Southampton, Southampton, UK SO16 7PX.
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Cookson SJ, Williams LE, Miller AJ. Light-dark changes in cytosolic nitrate pools depend on nitrate reductase activity in Arabidopsis leaf cells. Plant Physiol 2005; 138:1097-105. [PMID: 15908593 PMCID: PMC1150423 DOI: 10.1104/pp.105.062349] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Several different cellular processes determine the size of the metabolically available nitrate pool in the cytoplasm. These processes include not only ion fluxes across the plasma membrane and tonoplast but also assimilation by the activity of nitrate reductase (NR). In roots, the maintenance of cytosolic nitrate activity during periods of nitrate starvation and resupply (M. van der Leij, S.J. Smith, A.J. Miller [1998] Planta 205: 64-72; R.-G. Zhen, H.-W. Koyro, R.A. Leigh, A.D. Tomos, A.J. Miller [1991] Planta 185: 356-361) suggests that this pool is regulated. Under nitrate-replete conditions vacuolar nitrate is a membrane-bound store that can release nitrate to the cytoplasm; after depletion of cytosolic nitrate, tonoplast transporters would serve to restore this pool. To study the role of assimilation, specifically the activity of NR in regulating the size of the cytosolic nitrate pool, we have compared wild-type and mutant plants. In leaf mesophyll cells, light-to-dark transitions increase cytosolic nitrate activity (1.5-2.8 mm), and these changes were reversed by dark-to-light transitions. Such changes were not observed in nia1nia2 NR-deficient plants indicating that this change in cytosolic nitrate activity was dependent on the presence of functional NR. Furthermore, in the dark, the steady-state cytosolic nitrate activities were not statistically different between the two types of plant, indicating that NR has little role in determining resting levels of nitrate. Epidermal cells of both wild type and NR mutants had cytosolic nitrate activities that were not significantly different from mesophyll cells in the dark and were unaltered by dark-to-light transitions. We propose that the NR-dependent changes in cytosolic nitrate provide a cellular mechanism for the diurnal changes in vacuolar nitrate storage, and the results are discussed in terms of the possible signaling role of cytosolic nitrate.
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Affiliation(s)
- Sarah J Cookson
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, United Kingdom
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Mills RF, Francini A, Ferreira da Rocha PSC, Baccarini PJ, Aylett M, Krijger GC, Williams LE. The plant P1B-type ATPase AtHMA4 transports Zn and Cd and plays a role in detoxification of transition metals supplied at elevated levels. FEBS Lett 2005; 579:783-91. [PMID: 15670847 DOI: 10.1016/j.febslet.2004.12.040] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [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: 08/03/2004] [Revised: 11/10/2004] [Accepted: 12/05/2004] [Indexed: 10/26/2022]
Abstract
The transition metal Zn is essential for many physiological processes in plants, yet at elevated concentrations this, and the related non-essential metal Cd, can be toxic. Arabidopsis thaliana HMA4, belonging to the Type P1B subfamily of P-type ATPases, has recently been implicated in Zn nutrition, having a role in root to shoot Zn translocation. Using Arabidopsis insertional mutants, it is shown here that disruption of AtHMA4 function also results in increased sensitivity to elevated levels of Cd and Zn, suggesting that AtHMA4 serves an important role in metal detoxification at higher metal concentrations. AtHMA4 and a truncated form lacking the last 457 amino acids both confer Cd and Zn resistance to yeast but a mutant version of the full-length AtHMA4 (AtHMA4-C357G) does not; this demonstrates that the C-terminal region is not essential for this function. Evidence is presented that AtHMA4 functions as an efflux pump.
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Affiliation(s)
- Rebecca F Mills
- School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, UK
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Williams LE, Gregory A. Changes in the expression pattern of the plasma membrane H+-ATPase in developing Ricinus communis cotyledons undergoing the sink/source transition. Planta 2004; 218:562-568. [PMID: 14661107 DOI: 10.1007/s00425-003-1149-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Accepted: 10/10/2003] [Indexed: 05/24/2023]
Abstract
The plasma membrane (PM) H+-ATPase is thought to play a key role in generating the proton motive force used to drive the uptake and accumulation of solutes in plant cells. Changes in its expression pattern were studied in the Ricinus communis L. cotyledon as it changed from a sink to a source organ. Expression was monitored in 3-, 10- and 14-day-old cotyledons using an antibody to the maize PM H+-ATPase. The antibody labelled a 100-kDa protein in membrane fractions prepared from cotyledons and this protein occurred at higher levels in the PM-enriched fractions compared to those enriched in intracellular membranes. Immunostaining of tissue sections of 3-day-old Ricinus cotyledons (sinks) with this antibody demonstrated that the PM H+-ATPase was highly expressed in the lower epidermal cells and also in the vascular bundles, particularly the phloem. The high expression in the epidermis suggests that these cells may be important in the initial active uptake of solutes from the endosperm. A similar distribution was observed in the 10-day-old seedlings but, in addition, larger, more spherical cells (idioblasts) had developed in the lower and upper epidermal layers and these were also labelled. In 14-day-old seedlings the cotyledons are no longer reliant on nutrients from the endosperm (which has totally degraded) and they are functioning as source organs. This is reflected in a decrease in PM H+-ATPase expression in the lower epidermal cells, apart from idioblasts and stomatal guard cells. The latter were also observed in the upper epidermis. Expression remained high in the vascular bundles of 14-day-old seedlings with strong staining in the phloem.
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Affiliation(s)
- Lorraine E Williams
- School of Biological Sciences, The University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK.
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Abstract
Transition metals such as Fe, Cu, Mn, and Zn are essential minerals for normal plant growth and development, although they can be toxic when present in excess. Thus, for healthy plant growth, a range of transition metals must be acquired from the soil, distributed around the plant, and their concentrations carefully regulated within different cells and organelles. Membrane transport systems are likely to play a central role in these processes. The application of powerful genetic and molecular techniques has now identified a range of gene families that are likely to be involved in transition metal transport. These include the heavy metal ATPases (HMAs), the Nramps, the cation diffusion facilitator (CDF) family, the ZIP family, and the cation antiporters. This review provides a broad overview of the range of potential transport systems now thought to be involved in the uptake, distribution and homeostasis of transition metals in plants.
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Affiliation(s)
- J L Hall
- School of Biological Sciences, Biomedical Sciences Building, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK.
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47
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Maathuis FJM, Filatov V, Herzyk P, Krijger GC, Axelsen KB, Chen S, Green BJ, Li Y, Madagan KL, Sánchez-Fernández R, Forde BG, Palmgren MG, Rea PA, Williams LE, Sanders D, Amtmann A. Transcriptome analysis of root transporters reveals participation of multiple gene families in the response to cation stress. Plant J 2003; 35:675-92. [PMID: 12969422 DOI: 10.1046/j.1365-313x.2003.01839.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant nutrition critically depends on the activity of membrane transporters that translocate minerals from the soil into the plant and are responsible for their intra- and intercellular distribution. Most plant membrane transporters are encoded by multigene families whose members often exhibit overlapping expression patterns and a high degree of sequence homology. Furthermore, many inorganic nutrients are transported by more than one transporter family. These considerations, coupled with a large number of so-far non-annotated putative transporter genes, hamper our progress in understanding how the activity of specific transporters is integrated into a response to fluctuating conditions. We designed an oligonucleotide microarray representing 1096 Arabidopsis transporter genes and analysed the root transporter transcriptome over a 96-h period with respect to 80 mM NaCl, K+ starvation and Ca2+ starvation. Our data show that cation stress led to changes in transcript level of many genes across most transporter gene families. Analysis of transcriptionally modulated genes across all functional groups of transporters revealed families such as V-type ATPases and aquaporins that responded to all treatments, and families - which included putative non-selective cation channels for the NaCl treatment and metal transporters for Ca2+ starvation conditions - that responded to specific ionic environments. Several gene families including primary pumps, antiporters and aquaporins were analysed in detail with respect to the mRNA levels of different isoforms during ion stress. Cluster analysis allowed identification of distinct expression profiles, and several novel putative regulatory motifs were discovered within sets of co-expressed genes.
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Affiliation(s)
- Frans J M Maathuis
- Department of Biology, University of York, PO Box 373, York YO10 5YW, UK
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48
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Mills RF, Krijger GC, Baccarini PJ, Hall JL, Williams LE. Functional expression of AtHMA4, a P1B-type ATPase of the Zn/Co/Cd/Pb subclass. Plant J 2003; 35:164-176. [PMID: 12848823 DOI: 10.1046/j.1365-313xx.2003.01790.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mechanisms are required by all organisms to maintain the concentration of essential heavy metals (e.g. Zn and Cu) within physiological limits and to minimise the detrimental effects of non-essential heavy metals (e.g. Cd). Heavy-metal P-type ATPases (HMAs) are a subgroup of the P-type ATPase superfamily that may contribute to metal homeostasis in plants. We cloned and characterised a member of this family, AtHMA4, from Arabidopsis thaliana that clusters with the Zn/Co/Cd/Pb subclass of HMAs on phylogenetic analysis. Sequencing of the AtHMA4 cDNA showed that it contained the conserved motifs found in all P-type ATPases and also motifs that are characteristic of heavy-metal ATPases. Escherichia coli mutants defective in the HMAs, CopA and ZntA, were used in functional complementation studies. AtHMA4 was able to restore growth at high [Zn] in the zntA mutant but not at high [Cu] in the copA mutant, suggesting a role in zinc transport. Heterologous expression of AtHMA4 in Saccharomyces cerevisiae made the yeast more resistant to Cd but did not affect sensitivity to other metals compared with vector-transformed controls. The organ specificity of AtHMA4 was analysed in Arabidopsis and showed that AtHMA4 was expressed in a range of tissues with highest expression in roots. AtHMA4 was upregulated in roots exposed to elevated levels of Zn and Mn but downregulated by Cd. Possible physiological roles of this transporter in Arabidopsis are discussed.
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Affiliation(s)
- Rebecca F Mills
- School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, UK
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49
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Abstract
Mechanisms are required by all organisms to maintain the concentration of essential heavy metals (e.g. Zn and Cu) within physiological limits and to minimise the detrimental effects of non-essential heavy metals (e.g. Cd). Heavy-metal P-type ATPases (HMAs) are a subgroup of the P-type ATPase superfamily that may contribute to metal homeostasis in plants. We cloned and characterised a member of this family, AtHMA4, from Arabidopsis thaliana that clusters with the Zn/Co/Cd/Pb subclass of HMAs on phylogenetic analysis. Sequencing of the AtHMA4 cDNA showed that it contained the conserved motifs found in all P-type ATPases and also motifs that are characteristic of heavy-metal ATPases. Escherichia coli mutants defective in the HMAs, CopA and ZntA, were used in functional complementation studies. AtHMA4 was able to restore growth at high [Zn] in the zntA mutant but not at high [Cu] in the copA mutant, suggesting a role in zinc transport. Heterologous expression of AtHMA4 in Saccharomyces cerevisiae made the yeast more resistant to Cd but did not affect sensitivity to other metals compared with vector-transformed controls. The organ specificity of AtHMA4 was analysed in Arabidopsis and showed that AtHMA4 was expressed in a range of tissues with highest expression in roots. AtHMA4 was upregulated in roots exposed to elevated levels of Zn and Mn but downregulated by Cd. Possible physiological roles of this transporter in Arabidopsis are discussed.
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Affiliation(s)
- Rebecca F Mills
- School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, Southampton SO16 7PX, UK
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50
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Fotopoulos V, Gilbert MJ, Pittman JK, Marvier AC, Buchanan AJ, Sauer N, Hall JL, Williams LE. The monosaccharide transporter gene, AtSTP4, and the cell-wall invertase, Atbetafruct1, are induced in Arabidopsis during infection with the fungal biotroph Erysiphe cichoracearum. Plant Physiol 2003; 132:821-9. [PMID: 12805612 PMCID: PMC167022 DOI: 10.1104/pp.103.021428] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2003] [Revised: 02/23/2003] [Accepted: 02/23/2003] [Indexed: 05/18/2023]
Abstract
Powdery mildew fungi are biotrophic pathogens that form a complex interface, the haustorium, between the host plant and the parasite. The pathogen acts as an additional sink, competing with host sinks, resulting in considerable modification of photoassimilate production and partitioning within the host tissue. Here, we examine the factors that may contribute to these changes. We show for the first time in one biotrophic interaction (Arabidopsis/Erysiphe cichoracearum) all of the following responses: Glc uptake in host tissues is enhanced after fungal infection; this coincides with the induction of expression of the monosaccharide transporter gene, Arabidopsis sugar transport protein 4 (AtSTP4), in infected leaves; invertase activity and transcript levels for a cell wall invertase, Atbetafruct1, increase substantially in Arabidopsis during attack by this pathogen. Before infection, Arabidopsis plants transformed with an AtSTP4 promoter-beta-glucuronidase construct show expression mainly in sink tissues such as roots; after infection, AtSTP4 expression is induced in the mature leaves and increases over the 6-d time period. Sections of infected leaves stained for beta-glucuronidase show that AtSTP4 expression is not confined to infected epidermal cells but is also evident in a wider range of cells, including those of the vascular tissue. The results are discussed in relation to the possible coordinated expression of hexose transporters and cell wall invertase in the host response to powdery mildew infection.
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Affiliation(s)
- Vasileios Fotopoulos
- School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, United Kingdom
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