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Butterworth S, Torelli F, Lockyer EJ, Wagener J, Song OR, Broncel M, Russell MRG, Moreira-Souza ACA, Young JC, Treeck M. Toxoplasma gondii virulence factor ROP1 reduces parasite susceptibility to murine and human innate immune restriction. PLoS Pathog 2022; 18:e1011021. [PMID: 36476844 PMCID: PMC9762571 DOI: 10.1371/journal.ppat.1011021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/19/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Toxoplasma gondii is an intracellular parasite that can infect many host species and is a cause of significant human morbidity worldwide. T. gondii secretes a diverse array of effector proteins into the host cell which are critical for infection. The vast majority of these secreted proteins have no predicted functional domains and remain uncharacterised. Here, we carried out a pooled CRISPR knockout screen in the T. gondii Prugniaud strain in vivo to identify secreted proteins that contribute to parasite immune evasion in the host. We demonstrate that ROP1, the first-identified rhoptry protein of T. gondii, is essential for virulence and has a previously unrecognised role in parasite resistance to interferon gamma-mediated innate immune restriction. This function is conserved in the highly virulent RH strain of T. gondii and contributes to parasite growth in both murine and human macrophages. While ROP1 affects the morphology of rhoptries, from where the protein is secreted, it does not affect rhoptry secretion. Finally, we show that ROP1 co-immunoprecipitates with the host cell protein C1QBP, an emerging regulator of innate immune signaling. In summary, we identify putative in vivo virulence factors in the T. gondii Prugniaud strain and show that ROP1 is an important and previously overlooked effector protein that counteracts both murine and human innate immunity.
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Affiliation(s)
- Simon Butterworth
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Francesca Torelli
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Eloise J. Lockyer
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Jeanette Wagener
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Ok-Ryul Song
- High-Throughput Screening Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Malgorzata Broncel
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Matt R. G. Russell
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | | | - Joanna C. Young
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Moritz Treeck
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
- * E-mail:
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Asaaga FA, Young JC, Oommen MA, Chandarana R, August J, Joshi J, Chanda MM, Vanak AT, Srinivas PN, Hoti SL, Seshadri T, Purse BV. Operationalising the "One Health" approach in India: facilitators of and barriers to effective cross-sector convergence for zoonoses prevention and control. BMC Public Health 2021; 21:1517. [PMID: 34362321 PMCID: PMC8342985 DOI: 10.1186/s12889-021-11545-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There is a strong policy impetus for the One Health cross-sectoral approach to address the complex challenge of zoonotic diseases, particularly in low/lower middle income countries (LMICs). Yet the implementation of this approach in LMIC contexts such as India has proven challenging, due partly to the relatively limited practical guidance and understanding on how to foster and sustain cross-sector collaborations. This study addresses this gap by exploring the facilitators of and barriers to successful convergence between the human, animal and environmental health sectors in India. METHODS A mixed methods study was conducted using a detailed content review of national policy documents and in-depth semi-structured interview data on zoonotic disease management in India. In total, 29 policy documents were reviewed and 15 key informant interviews were undertaken with national and state level policymakers, disease managers and experts operating within the human-animal-environment interface of zoonotic disease control. RESULTS Our findings suggest that there is limited policy visibility of zoonotic diseases, although global zoonoses, especially those identified to be of pandemic potential by international organisations (e.g. CDC, WHO and OIE) rather than local, high burden endemic diseases, have high recognition in the existing policy agenda setting. Despite the widespread acknowledgement of the importance of cross-sectoral collaboration, a myriad of factors operated to either constrain or facilitate the success of cross-sectoral convergence at different stages (i.e. information-sharing, undertaking common activities and merging resources and infrastructure) of cross-sectoral action. Importantly, participants identified the lack of supportive policies, conflicting departmental priorities and limited institutional capacities as major barriers that hamper effective cross-sectoral collaboration on zoonotic disease control. Building on existing informal inter-personal relationships and collaboration platforms were suggested by participants as the way forward. CONCLUSION Our findings point to the importance of strengthening existing national policy frameworks as a first step for leveraging cross-sectoral capacity for improved disease surveillance and interventions. This requires the contextual adaptation of the One Health approach in a manner that is sensitive to the underlying socio-political, institutional and cultural context that determines and shapes outcomes of cross-sector collaborative arrangements.
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Affiliation(s)
- F A Asaaga
- UK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK.
| | - J C Young
- UK Centre for Ecology & Hydrology, Edinburgh, EH26 0QB, UK
- Agroécologie, AgroSup Dijon, INRAE, Univ. Bourgogne, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - M A Oommen
- Ashoka Trust for Research in Ecology and the Environment, Bengaluru, 560 054, India
| | - R Chandarana
- Ashoka Trust for Research in Ecology and the Environment, Bengaluru, 560 054, India
| | - J August
- Oxford Brookes University, Headington Campus, Oxford, OX3 0BP, UK
| | - J Joshi
- Centre for Disease Dynamics, Economics & Policy, B-25, Lajpat Nagar-2, New Delhi, India
| | - M M Chanda
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics, Ramagondanahalli, Yelahanka New Town, Bengaluru, Karnataka, 560064, India
| | - A T Vanak
- Ashoka Trust for Research in Ecology and the Environment, Bengaluru, 560 054, India
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, 3209, South Africa
- DBT-Wellcome Trust India Alliance, Hyderabad, 500034, India
| | - P N Srinivas
- Institute of Public Health, Banashankari 2nd Stage, Bangalore, 560 070, India
| | - S L Hoti
- ICMR-National Institute for Traditional Medicine, Belgavi, Karnataka, 590010, India
| | - T Seshadri
- Agroécologie, AgroSup Dijon, INRAE, Univ. Bourgogne, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - B V Purse
- UK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
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Young JC, Broncel M, Teague H, Russell MRG, McGovern OL, Renshaw M, Frith D, Snijders AP, Collinson L, Carruthers VB, Ewald SE, Treeck M. Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection. mSphere 2020; 5:e00792-20. [PMID: 32907954 PMCID: PMC7485689 DOI: 10.1128/msphere.00792-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 01/07/2023] Open
Abstract
The intracellular parasite Toxoplasma gondii resides within a membrane-bound parasitophorous vacuole (PV) and secretes an array of proteins to establish this replicative niche. It has been shown previously that Toxoplasma secretes kinases and that numerous proteins are phosphorylated after secretion. Here, we assess the role of the phosphorylation of strand-forming protein 1 (SFP1) and the related protein GRA29, two secreted proteins with unknown function. We show that both proteins form stranded structures in the PV that are independent of the previously described intravacuolar network or actin. SFP1 and GRA29 can each form these structures independently of other Toxoplasma secreted proteins, although GRA29 appears to regulate SFP1 strands. We show that an unstructured region at the C termini of SFP1 and GRA29 is required for the formation of strands and that mimicking the phosphorylation of this domain of SFP1 negatively regulates strand development. When tachyzoites convert to chronic-stage bradyzoites, both proteins show a dispersed localization throughout the cyst matrix. Many secreted proteins are reported to dynamically redistribute as the cyst forms, and secreted kinases are known to play a role in cyst formation. Using quantitative phosphoproteome and proteome analyses comparing tachyzoite and early bradyzoite stages, we reveal widespread differential phosphorylation of secreted proteins. While we found no direct evidence for phosphorylation playing a dominant role for SFP1/GRA29 redistribution in the cyst, these data support a model in which secreted kinases and phosphatases contribute to the regulation of secreted proteins during stage conversion.IMPORTANCEToxoplasma gondii is a common parasite that infects up to one-third of the human population. Initially, the parasite grows rapidly, infecting and destroying cells of the host, but subsequently switches to a slow-growing form and establishes chronic infection. In both stages, the parasite lives within a membrane-bound vacuole within the host cell, but in the chronic stage, a durable cyst wall is synthesized, which provides protection to the parasite during transmission to a new host. Toxoplasma secretes proteins into the vacuole to build its replicative niche, and previous studies identified many of these proteins as phosphorylated. We investigate two secreted proteins and show that a phosphorylated region plays an important role in their regulation in acute stages. We also observed widespread phosphorylation of secreted proteins when parasites convert from acute to chronic stages, providing new insight into how the cyst wall may be dynamically regulated.
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Affiliation(s)
- Joanna C Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Helena Teague
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Matt R G Russell
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Olivia L McGovern
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Matt Renshaw
- Advanced Light Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - David Frith
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Ambrosius P Snijders
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sarah E Ewald
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
- Carter Immunology Center, University of Virginia, Charlottesville, Virginia, USA
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
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Broncel M, Dominicus C, Vigetti L, Nofal SD, Bartlett EJ, Touquet B, Hunt A, Wallbank BA, Federico S, Matthews S, Young JC, Tate EW, Tardieux I, Treeck M. Profiling of myristoylation in Toxoplasma gondii reveals an N-myristoylated protein important for host cell penetration. eLife 2020; 9:e57861. [PMID: 32618271 PMCID: PMC7373427 DOI: 10.7554/elife.57861] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/27/2020] [Indexed: 12/26/2022] Open
Abstract
N-myristoylation is a ubiquitous class of protein lipidation across eukaryotes and N-myristoyl transferase (NMT) has been proposed as an attractive drug target in several pathogens. Myristoylation often primes for subsequent palmitoylation and stable membrane attachment, however, growing evidence suggests additional regulatory roles for myristoylation on proteins. Here we describe the myristoylated proteome of Toxoplasma gondii using chemoproteomic methods and show that a small-molecule NMT inhibitor developed against related Plasmodium spp. is also functional in Toxoplasma. We identify myristoylation on a transmembrane protein, the microneme protein 7 (MIC7), which enters the secretory pathway in an unconventional fashion with the myristoylated N-terminus facing the lumen of the micronemes. MIC7 and its myristoylation play a crucial role in the initial steps of invasion, likely during the interaction with and penetration of the host cell. Myristoylation of secreted eukaryotic proteins represents a substantial expansion of the functional repertoire of this co-translational modification.
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Affiliation(s)
- Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Caia Dominicus
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Luis Vigetti
- Institute for Advanced Biosciences, Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble AlpesGrenobleFrance
| | - Stephanie D Nofal
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Edward J Bartlett
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City CampusLondonUnited Kingdom
| | - Bastien Touquet
- Institute for Advanced Biosciences, Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble AlpesGrenobleFrance
| | - Alex Hunt
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Bethan A Wallbank
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Stefania Federico
- The Peptide Chemistry STP, The Francis Crick InstituteLondonUnited Kingdom
| | - Stephen Matthews
- Department of Life Sciences, Imperial College London, South KensingtonLondonUnited Kingdom
| | - Joanna C Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Edward W Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City CampusLondonUnited Kingdom
| | - Isabelle Tardieux
- Institute for Advanced Biosciences, Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble AlpesGrenobleFrance
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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Beraki T, Hu X, Broncel M, Young JC, O'Shaughnessy WJ, Borek D, Treeck M, Reese ML. Divergent kinase regulates membrane ultrastructure of the Toxoplasma parasitophorous vacuole. Proc Natl Acad Sci U S A 2019; 116:6361-6370. [PMID: 30850550 PMCID: PMC6442604 DOI: 10.1073/pnas.1816161116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Apicomplexan parasites replicate within a protective organelle, called the parasitophorous vacuole (PV). The Toxoplasma gondii PV is filled with a network of tubulated membranes, which are thought to facilitate trafficking of effectors and nutrients. Despite being critical to parasite virulence, there is scant mechanistic understanding of the network's functions. Here, we identify the parasite-secreted kinase WNG1 (With-No-Gly-loop) as a critical regulator of tubular membrane biogenesis. WNG1 family members adopt an atypical protein kinase fold lacking the glycine rich ATP-binding loop that is required for catalysis in canonical kinases. Unexpectedly, we find that WNG1 is an active protein kinase that localizes to the PV lumen and phosphorylates PV-resident proteins, several of which are essential for the formation of a functional intravacuolar network. Moreover, we show that WNG1-dependent phosphorylation of these proteins is required for their membrane association, and thus their ability to tubulate membranes. Consequently, WNG1 knockout parasites have an aberrant PV membrane ultrastructure. Collectively, our results describe a unique family of Toxoplasma kinases and implicate phosphorylation of secreted proteins as a mechanism of regulating PV development during parasite infection.
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Affiliation(s)
- Tsebaot Beraki
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Xiaoyu Hu
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Joanna C Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - William J O'Shaughnessy
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Dominika Borek
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Michael L Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390;
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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Butler JRA, Young JC, McMyn IAG, Leyshon B, Graham IM, Walker I, Baxter JM, Dodd J, Warburton C. Evaluating adaptive co-management as conservation conflict resolution: Learning from seals and salmon. J Environ Manage 2015; 160:212-225. [PMID: 26144563 DOI: 10.1016/j.jenvman.2015.06.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [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: 12/04/2014] [Revised: 05/12/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
By linking iterative learning and knowledge generation with power-sharing, adaptive co-management (ACM) provides a potential solution to resolving complex social-ecological problems. In this paper we evaluate ACM as a mechanism for resolving conservation conflict using a case study in Scotland, where seal and salmon fishery stakeholders have opposing and entrenched objectives. ACM emerged in 2002, successfully resolving this long-standing conflict. Applying evaluation approaches from the literature, in 2011 we interviewed stakeholders to characterise the evolution of ACM, and factors associated with its success over 10 years. In common with other ACM cases, triggers for the process were shifts in slow variables controlling the system (seal and salmon abundance, public perceptions of seal shooting), and exogenous shocks (changes in legal mandates, a seal disease outbreak). Also typical of ACM, three phases of evolution were evident: emerging local leadership preparing the system for change, a policy window of opportunity, and stakeholder partnerships building the resilience of the system. Parameters maintaining ACM were legal mechanisms and structures, legal power held by government, and the willingness of all stakeholders to reach a compromise and experiment with an alternative governance approach. Results highlighted the critical role of government power and support in resolving conservation conflict, which may constrain the extent of local stakeholder-driven ACM. The evaluation also demonstrated how, following perceived success, the trajectory of ACM has shifted to a 'stakeholder apathy' phase, with declining leadership, knowledge exchange, stakeholder engagement, and system resilience. We discuss remedial actions required to revive the process, and the importance of long term government resourcing and alternative financing schemes for successful conflict resolution. Based on the results we present a generic indicator framework and participatory method for the longitudinal evaluation of ACM applied to conservation conflict resolution.
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Affiliation(s)
- J R A Butler
- CSIRO Land and Water Flagship, GPO Box 2583, Brisbane, QLD, 4001, Australia.
| | - J C Young
- NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, EH26 0QB, UK.
| | - I A G McMyn
- ECUS Ltd., Scion House, Stirling University Innovation Park, Stirling, FK9 4NF, UK.
| | - B Leyshon
- Scottish Natural Heritage, Dingwall Business Park, Dingwall, Ross-shire, IV15 9XB, UK.
| | - I M Graham
- Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty, IV11 8YL, UK.
| | - I Walker
- Scottish Government Wildlife and Habitats Division, Area G-H93, Victoria Quay, Edinburgh, EH6 6QQ, UK.
| | - J M Baxter
- Scottish Natural Heritage, Silvan House, 3rd Floor East, 231 Corstorphine Road, Edinburgh, EH12 7AT, UK.
| | - J Dodd
- Scottish Natural Heritage, Cameron House, Oban, Argyll, PA34 4AE, UK.
| | - C Warburton
- Wild Scotland, Old Town Jail, St. John Street, Stirling, FK8 1EA, UK.
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Young JC, Clements A, Lang AE, Garnett JA, Munera D, Arbeloa A, Pearson J, Hartland EL, Matthews SJ, Mousnier A, Barry DJ, Way M, Schlosser A, Aktories K, Frankel G. The Escherichia coli effector EspJ blocks Src kinase activity via amidation and ADP ribosylation. Nat Commun 2014; 5:5887. [PMID: 25523213 PMCID: PMC4284639 DOI: 10.1038/ncomms6887] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [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: 08/04/2014] [Accepted: 11/17/2014] [Indexed: 12/01/2022] Open
Abstract
The hallmark of enteropathogenic Escherichia coli (EPEC) infection is the formation of actin-rich pedestal-like structures, which are generated following phosphorylation of the bacterial effector Tir by cellular Src and Abl family tyrosine kinases. This leads to recruitment of the Nck-WIP-N-WASP complex that triggers Arp2/3-dependent actin polymerization in the host cell. The same phosphorylation-mediated signalling network is also assembled downstream of the Vaccinia virus protein A36 and the phagocytic Fc-gamma receptor FcγRIIa. Here we report that the EPEC type-III secretion system effector EspJ inhibits autophosphorylation of Src and phosphorylation of the Src substrates Tir and FcγRIIa. Consistent with this, EspJ inhibits actin polymerization downstream of EPEC, Vaccinia virus and opsonized red blood cells. We identify EspJ as a unique adenosine diphosphate (ADP) ribosyltransferase that directly inhibits Src kinase by simultaneous amidation and ADP ribosylation of the conserved kinase-domain residue, Src E310, resulting in glutamine-ADP ribose.
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Affiliation(s)
- Joanna C. Young
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
| | - Abigail Clements
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
| | - Alexander E. Lang
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, D-79104 Freiburg, Germany
| | - James A. Garnett
- Centre for Structural Biology, Imperial College, SW7 2AZ London, UK
| | - Diana Munera
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
| | - Ana Arbeloa
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
| | - Jaclyn Pearson
- Department of Microbiology and Immunology, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne Victoria 3010, Australia
| | - Elizabeth L. Hartland
- Department of Microbiology and Immunology, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne Victoria 3010, Australia
| | | | - Aurelie Mousnier
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
| | - David J. Barry
- Cell Motility Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Michael Way
- Cell Motility Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Wuerzburg, 97080 Würzburg, Germany
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, D-79104 Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, D-79104 Freiburg, Germany
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Imperial College, SW7 2AZ London, UK
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Abstract
Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection.
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Affiliation(s)
- Abigail Clements
- Centre for Molecular Microbiology and Infection, Imperial College, London, UK.
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9
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Li XZ, Zhu C, de Lange CFM, Zhou T, He J, Yu H, Gong J, Young JC. Efficacy of detoxification of deoxynivalenol-contaminated corn by Bacillus sp. LS100 in reducing the adverse effects of the mycotoxin on swine growth performance. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2011; 28:894-901. [PMID: 21614709 DOI: 10.1080/19440049.2011.576402] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Biodetoxification of mycotoxins is a novel strategy to control mycotoxicoses in animals. Bacillus sp. LS100, which transforms deoxynivalenol (DON) to a less toxic chemical de-epoxy DON (DOM-1), was evaluated for its efficacy in reducing the adverse effects of DON on swine growth performance. A feeding trial was conducted in growing pigs with four treatments: (1) corn meal without detectable DON served as control (Non-toxic Corn); (2) Fusarium-infected corn giving a toxic diet containing 5 µg DON g(-1) (Toxic Corn); (3) Toxic Corn detoxified with Bacillus sp. LS100 giving a detoxified diet containing 5 µg DOM-1 g(-1) (LS100-De-toxic Corn); (4) Non-toxic Corn treated with Bacillus sp. LS100 serving as bacterial control (LS100-Non-toxic Corn). During 9 days of exposure to the treatments, pigs on Toxic Corn showed a significant reduction in daily feed consumption, daily weight gain and feed efficiency by 29, 48 and 29%, respectively, compared to pigs on Non-toxic Corn. These parameters of the pigs fed LS100-De-toxic Corn diet were 45, 82 and 32% greater, respectively, than those of pigs fed Toxic Corn diet, and were similar to those pigs fed Non-toxic Corn and LS100-Non-toxic Corn diets. There were no significant differences between the treatments of LS100-Non-toxic Corn and Non-toxic Corn diets, implying that the bacterial isolate might not have significantly affected nutrition and palatability of the feed or had negative effects on the pig's feeding performance. The results have proved that microbial detoxification of DON in contaminated feed can eliminate negative effects of the mycotoxin, and the pre-feeding detoxification approach may be applied in the livestock industry.
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Affiliation(s)
- X-Z Li
- a Guelph Food Research Centre , Agriculture and Agri-Food Canada , Guelph , Ontario , Canada N1G 5C9
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DeLuca L, Erb HN, Young JC, Perkins GA, Ainsworth DM. The effect of adding oral dexamethasone to feed alterations on the airway cell inflammatory gene expression in stabled horses affected with recurrent airway obstruction. J Vet Intern Med 2008; 22:427-35. [PMID: 18346142 DOI: 10.1111/j.1939-1676.2008.0055.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Chemokine expression in airway epithelium and bronchoalveolar lavage fluid (BALF) cells of horses with recurrent airway obstruction (RAO) is increased. HYPOTHESIS For RAO-affected horses that are stabled and fed a pelleted ration, the addition of oral dexamethasone further improves pulmonary function and reduces inflammatory gene expression in pulmonary cells. ANIMALS Twelve RAO-affected horses. METHODS In a randomized cross-over experiment, the effect of feeding pellets in lieu of hay to stabled, RAO-affected horses was compared with the effect of feeding pellets and administering a 21-day decreasing dose regimen of oral dexamethasone on the expression (by kinetic polymerase chain reaction) of interleukin-8 (IL-8), chemokine (C-X-C motif) ligand 2 (CXCL2), IL-1beta, IL-6, and beta-actin in the BALF cells and of IL-8, CXCL2, 2 IL-1 receptor (IL-1R2), Toll-like receptor 4 (TLR4), and glyceraldehyde 3-phosphate dehydrogenase in the bronchial epithelium 2 days after the final dose. RESULTS Both treatments reduced airway neutrophilia and breathing efforts but the addition of dexamethasone was associated with fewer treatment failures. Compared with feed changes alone, dexamethasone administration further reduced the expression of IL-8, CXCL2, and IL-1beta in the BALF cells 3.3-, 2.5-, and 4.7-fold, respectively. In the airway epithelium, both treatments were equally efficacious in reducing the expression of IL-8 and CXCL2 expression relative to pretreatment values, but either treatment failed to alter the expression of IL-1R2 and TLR4. CONCLUSIONS AND CLINICAL IMPORTANCE For a rapid and consistent improvement in pulmonary function and a reduction in inflammatory gene expression of the BALF cells, a decreasing dose of oral dexamethasone in combination with feed alterations is more efficacious for horses that must remain stabled.
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Affiliation(s)
- L DeLuca
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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11
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Young JC, Wu S, Hansteen G, Du C, Sambucetti L, Remiszewski S, O'Farrell AM, Hill B, Lavau C, Murray LJ. Inhibitors of histone deacetylases promote hematopoietic stem cell self-renewal. Cytotherapy 2006; 6:328-36. [PMID: 16146885 DOI: 10.1080/14653240410004899] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Histone deacetylases (HDAC) are associated with a variety of transcriptional repressors that control cellular differentiation and proliferation. HDAC inhibitors such as trichostatin A, trapoxin and chlamydocin could be useful tools to modulate these cellular processes. We investigated their effect on the self-renewal of hematopoietic stem cells (HSC) during ex vivo culture. METHODS Purified murine HSC with the phenotype c-Kit+,Thy-1.1(lo), Lin(-/lo), Sca-1+ were cultured for 4 days with IL-3, IL-6 and c-Kit ligand without or with HDAC inhibitors, after which their degree of phenotypic differentiation in culture was assessed by flow cytometric analysis. To explore whether HDAC inhibitors could have a beneficial role in human HSC transplantation, mobilized peripheral blood CD34+ cells were cultured with thrombopoietin mimetic peptide, flt3 ligand, and c-Kit ligand, without or with various HDAC inhibitors. The fluorescent dye, carboxyfluorescein-diacetate succinimidylester (CFSE), was used to track division of cell subsets, and engrafting ability was evaluated in a non-obese diabetic (NOD) -SCID xenotransplantation model. RESULTS Murine HSC cultured with HDAC inhibitors maintained a more primitive phenotype than control cultures. The number of human HSC expressing Thy-1 increased up to seven-fold during a 5-day culture with HDAC inhibitors compared with control cultures. Chlamydocin was the most effective of the HDAC inhibitors tested at promoting Thy-1 expression on human cells. CFSE tracking showed that the increase in Thy-1+ cells resulted from cell division. In a NOD-SCID repopulation assay, cells exposed to chlamydocin for 24 h displayed an average four-fold higher engrafting ability over control cells. DISCUSSION Our studies suggest that HDAC inhibitors can induce ex vivo expansion of human HSC, and may improve engraftment in hematopoietic transplant patients when cell dose is limiting.
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12
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Cho YT, Young JC, Jordan JA, Moon HM. Factors affecting measurement of specific methanogenic activity. Water Sci Technol 2005; 52:435-40. [PMID: 16180461] [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] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Specific methane production (SMP) tests have been used to determine the potential loading rate capacity of anaerobic reactors, to characterize biomass prior to its use as an inoculum for new anaerobic reactors, to detect changes in biomass activity during operation, or to assess the occurrence of toxic conditions. SMP tests also provide a basis for estimating specific methanogenic activity in mixed anaerobic cultures. SMP protocols used to date have varied widely in both procedure and objective. Tests conducted by the present authors indicated that biomass concentration, substrate type and concentration, and mixing intensity are factors that can affect the results of SMP tests.
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Affiliation(s)
- Y T Cho
- Department of Environmental Engineering, Chung Cheong College, Cheongwon-Kun, Chung-Buk, Korea.
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13
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Raftopoulos Y, Nghiem DD, Gignac M, Young JC, Fowler D, Bergamaschi R. The impact of introducing laparoscopic donor nephrectomy to an established renal transplant program. Surg Endosc 2004; 18:1519-23. [PMID: 15791381 DOI: 10.1007/s00464-003-9220-8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 03/11/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Although the advent of hand-assisted laparoscopic donor nephrectomy (HLDN) has had a positive impact on the donor pool, there is still some concern about its safety. The aim of this study was to assess the impact of a change in surgical access to live-donor nephrectomy on donor-related complication rates, the renal function of the donor, and the graft function of the recipient. METHODS At our hospital, HLDN was introduced in 1998. Thereafter, we compared 49 consecutive donors undergoing open donor nephrectomy (ODN) between 1987 and 2002 with 57 consecutive donors undergoing HLDN between 1998 and 2002. Donor renal and recipient graft functions were assessed by measuring creatinine levels and urine output, with the addition of warm and cold ischemia time and dialysis requirements in the latter group. Data are presented as means (+/-SD) and analyzed with the Student t-test or Fisher's exact test. RESULTS The ODN and HLDN donors were comparable for age, gender, body mass index, renovascular anatomy, and preoperative creatinine. Estimated blood loss (370 +/- 280 vs 168 +/- 160 ml, p < 0.0001), time to resumption of oral intake (1.7 +/- 0.5 vs 1.3 +/- 0.7 days, p = 0.01), duration of intravenous narcotic requirements (23 +/- 0.7 vs 1.7 +/- 1.0 days, p < 0.0001), and hospital stay (4.2 +/- 1.4 vs 2.9 +/- 1.3 days, p < 0.0001) were significantly decreased after HLDN. There were no significant differences between ODN and HLDN in operating time (204 +/- 46 vs 202 +/- 49 min), donor-related complication rates (12.2% vs 14%), or donor renal and recipient graft functions. CONCLUSION The introduction of HLDN to an established renal transplant program led to an improved short-term outcome without any increase in donor-related complication rates or delay in recipient graft function.
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Affiliation(s)
- Y Raftopoulos
- Minimally Invasive Surgery Center, Drexel University Medical College Clinical Campus, Allegheny General Hospital, 320 East North Avenue, Pittsburgh, PA 15212, USA
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14
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Young JC, Lin K, Travis M, Hansteen G, Abitorabi A, Sirenko O, Murray L, Hill B. Investigation into an engraftment defect induced by culturing primitive hematopoietic cells with cytokines. Cytotherapy 2002; 3:307-20. [PMID: 12171719 DOI: 10.1080/146532401317070943] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Strategies for transplanting primitive hematopoietic progenitor (PHP) cells are under development that require in vitro manipulation of cells for several hours to several days prior to transplantation. This applies to gene-therapy protocols involving transduction with adenoviral or lentiviral vectors (typically 1 day of ex vivo culture) or retroviral vectors (up to 3 days of culture). METHODS Human mobilized peripheral blood (MPB) CD34(+) cells were cultured with the cytokines thrombopoietin mimetic peptide (mTPO), flt3 ligand (FL), and c-kit ligand (KL). Equal numbers of CD34(+) cells, either uncultured or cultured for various time periods up to 5 days, were tested for engraftment in sublethally irradiated 8-10 week-old NOD/SCID mice. Cells were also compared for expression and function of several key surface molecules. RESULTS At a limiting dose of 1 million cells, mice receiving uncultured cells had a mean of 20% CD45(+) (human) cells in their BM 6 weeks post-transplantation, versus 3% for mice receiving 3-5 day cultured cells. Analysis of 10 surface molecules, CD11a, CD18, CD29, CD49d, CD49e, CXCR-4, CD62L, CD31, CD43, and CD44 over a 5-day culture period showed that their expression levels were either maintained or up-regulated on CD34(+) cells and the primitive Thy-1(+) subset. Similar percentages of uncultured and 3-day cultured MPB CD34(+) cells bound to plates coated with vascular cell adhesion molecule-1 (VCAM-1) under both static and physiological flow conditions, and chemotaxis of cultured cells towards stromal-derived factor-1 (SDF-1) was not impaired, suggesting that VLA-4 and CXCR-4 were functional on cultured cells. CD34(+) Thy-1(+) MPB cells cultured with cytokines expressed increasing levels of Fas receptor beginning at 20 h in culture, with peak expression levels after 3 days (mean Day 0 expression, 39%; mean Day 3 expression, 86%), without increased apoptosis. Including inhibitors of caspases in the media of cells cultured for 24-48 h significantly improved their engraftment in a SCID-hu bone-engraftment model. DISCUSSION Increased susceptibility to apoptosis upon in vivo injection may contribute to impaired engraftment of in vitro manipulated cells. Inhibitors of apoptosis may increase their engrafting capacity in clinical settings.
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Affiliation(s)
- J C Young
- SyStemix Inc., Palo Alto, CA 94070 (a subsidiary of Novartis Pharmaceuticals), USA
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15
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Abstract
Sulfur-utilizing denitrification can be performed by denitrifying sulfur bacteria under autotrophic and heterotrophic conditions. To investigate the effect of organics (methanol and landfill leachate) on sulfur-utilizing denitrification, six laboratory-scale sulfur packed columns were operated under autotrophic, mixotrophic and heterotrophic conditions for approximately 1 year. The performance of the columns was monitored by measuring the pH, nitrate, nitrite, sulfate, sulfide, alkalinity dissolved organic carbon (DOC), and turbidity. These tests indicated that the mixotrophic column had a higher nitrate removal capacity than the autotrophic column. It was also found that under mixotrophic conditions, some portion of nitrate was removed heterotrophically and the remainder was denitrified by sulfur-utilizing autotrophic bacteria without inhibition by organics. In addition, sulfate production and alkalinity consumption were reduced under mixotrophic conditions. These results suggest that mixotrophic conditions that allow simultaneous reactions of autotrophic and heterotrophic denitrification provide significant advantages in terms of nitrate and DOC removal, sulfate production decrease, and alkalinity consumption over obligate autotrophic or heterotrophic denitrification.
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Affiliation(s)
- S E Oh
- Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), 1 Oryong-dong, Puk-gu, Kwangju 500-712, South Korea
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16
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Rosenhagen MC, Young JC, Wochnik GM, Herr AS, Schmidt U, Hartl FU, Holsboer F, Rein T. Synergistic inhibition of the glucocorticoid receptor by radicicol and benzoquinone ansamycins. Biol Chem 2001; 382:499-504. [PMID: 11347901 DOI: 10.1515/bc.2001.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Radicicol (RAD) and the benzoquinone ansamycin geldanamycin (GA) are potential anticancer drugs known to inhibit heat shock protein 90 (hsp90) and, therefore, the activation of proteins dependent on its function such as proto-oncogenic kinases and nuclear receptors. Using the glucocorticoid receptor (GR) as a model system we analysed the effects of RAD and various benzoquinone ansamycins. All compounds efficiently abolished GR-dependent transactivation. Surprisingly, whenever one of the ansamycins was applied in combination with RAD, synergistic inhibition of GR-dependent transcription and of hormone binding of GR was observed. In contrast, combination of two ansamycins showed no synergy. These findings suggest synergism within the hsp90 dimer and may open new ways to explore hsp90 as therapeutic target.
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18
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Abstract
STUDY OBJECTIVE We determine whether paramedics, using written guidelines, can accurately triage patients in the field. METHODS This prospective, descriptive study was conducted at an urban county emergency medical services (EMS) system and county hospital. Paramedics triaged patients, for study purposes only, according to 4 categories: (1) needing to come to the emergency department by advanced life support (ALS) transport, (2) needing to come to the ED by any transport, (3) needing to see a physician within 24 hours, or (4) not needing any further physician evaluation. Medical records that provided patient treatment information to the point of ED disposition were subsequently reviewed (blinded to the paramedic rating) to determine which of the categories was appropriate. The protocol of the EMS system of the study site dictates that all patients should be transported except for those who refuse care and leave against medical advice. Only transported patients were included in the present study. Fifty-four paramedics triaged 1,180 patients. RESULTS Mean patient age was 43.4+/-17 years; 62.0% were male. Paramedics rated 1,000 (84.7%) of the patients as needing to come to the ED and 180 (15.3%) as not needing to come to the ED. Ratings according to triage category were as follows: 804 (68.1%) category 1, 196 (16.6%) category 2, 148 (12.5%) category 3, and 32 (2.7%) category 4. Seven hundred thirty-six (62.4%) patients were discharged, 298 (25.3%) were admitted, 90 (7.6%) were transferred, 36 (3.1%) left against medical advice, and 20 (1.7%) died. The review panel determined that 113 (9.6%) patients were undertriaged; 55 (48.7%) of these patients were misclassified because the paramedics misused the guidelines. Ninety-nine patients (8.4% of the total sample) were incorrectly classified as not needing to come to the ED. This represented 55% of the patients (99/180) categorized as 3 or 4 by the paramedics. Fourteen patients (1.2% of total) were incorrectly classified as category 4 instead of 3. Of the 113 undertriaged patients, 22 (19.6%) were admitted, 86 (76.1%) were discharged, and 4 (3.5%) were transferred. CONCLUSION Paramedics using written guidelines fall short of an acceptable level of triage accuracy to determine disposition of patients in the field.
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Affiliation(s)
- J E Pointer
- Alameda County Emergency Medical Services Agency, Oakland, CA 94607, USA.
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19
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Burgeson CR, Wechsler H, Brener ND, Young JC, Spain CG. Physical education and activity: results from the School Health Policies and Programs Study 2000. J Sch Health 2001; 71:279-293. [PMID: 11586871 DOI: 10.1111/j.1746-1561.2001.tb03505.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- C R Burgeson
- Division of Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Mailstop K-12, 4770 Buford Highway, NE, Atlanta, GA 30341, USA.
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20
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Abstract
Hsp90 is unique among molecular chaperones. The majority of its known substrates are signal transduction proteins, and recent work indicates that it uses a novel protein-folding strategy.
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Affiliation(s)
- J C Young
- Cellular Biochemistry, Max Planck Institute for Biochemistry, Martinsried D-82152, Germany
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21
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Abstract
UNLABELLED One of the most successful reality-based television shows is The Learning Channel's "Trauma-Life in the ER," in which patients are filmed prior to being consented and camera crews are intimately intertwined in resuscitations. OBJECTIVE To assess provider and patient attitudes regarding privacy and satisfaction during filming. METHODS This was a prospective survey of patients and providers working in an urban, county teaching emergency department (ED). Scores of visual analog scales (VASs) for satisfaction, privacy, and willingness to return to the ED were accessed. RESULTS Eighty patients, 39 physicians and 39 nurses, were interviewed. On a 10-cm VAS where 0 = no invasion of patient privacy and 10 = extreme privacy invasion, the mean (+/-SD) rating by physicians was 5.4 (+/-2.6), by nurses was 4.9 (+/-3.1), and by patients was 2.3 (+/-3.2). There was no significant difference between physician and nurse ratings (p = 0.69), but patients rated invasion of privacy significantly lower (p < 0.0001). Filmed patients rated significantly higher invasion of privacy (3.8 +/- 4.1) than patients not filmed or those unsure whether they had been filmed (1.6 +/- 2.5); p < 0.01). On a 10-cm VAS where -5 = extreme decrease in satisfaction and 5 = extreme increase in satisfaction, the mean rating by physicians was -0.25 (+/-1.6), by nurses was -0.32 (+/-1.3), and by patients was 0.02 (+/-1.4). There was no statistical difference between the satisfaction levels of providers and patients (p = 0.19). CONCLUSIONS Providers rated invasion of patient privacy higher than patients rated their own invasion of privacy. Patients who were filmed rated invasion of privacy higher than patients who were not filmed. Filming had no significant effect on the satisfaction of providers or patients.
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Affiliation(s)
- R M Rodriguez
- Department of Emergency Medicine, Alameda County Medical Center, Highland Campus, Oakland, CA, USA.
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22
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Abstract
The alpha subunit of a prototypical heterotrimeric GTP-binding protein (G protein), which is encoded by a single gene (GPA1) in Arabidopsis, is a modulator of plant cell proliferation. gpa1 null mutants have reduced cell division in aerial tissues throughout development. Inducible overexpression of GPA1 in Arabidopsis confers inducible ectopic cell division. GPA1 overexpression in synchronized BY-2 cells causes premature advance of the nuclear cycle and the premature appearance of a division wall. Results from loss of function and ectopic expression and activation of GPA1 indicate that this subunit is a positive modulator of cell division in plants.
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Affiliation(s)
- H Ullah
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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23
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Bernhardt DT, Gomez J, Johnson MD, Martin TJ, Rowland TW, Small E, LeBlanc C, Malina R, Krein C, Young JC, Reed FE, Anderson SJ, Anderson SJ, Griesemer BA, Bar-Or O. Strength training by children and adolescents. Pediatrics 2001; 107:1470-2. [PMID: 11389279 DOI: 10.1542/peds.107.6.1470] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Pediatricians are often asked to give advice on the safety and efficacy of strength training programs for children and adolescents. This review, a revision of a previous American Academy of Pediatrics policy statement, defines relevant terminology and provides current information on risks and benefits of strength training for children and adolescents.
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24
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Washington RL, Bernhardt DT, Gomez J, Johnson MD, Martin TJ, Rowland TW, Small E, LeBlanc C, Krein C, Malina R, Young JC, Reed FE, Anderson S, Bolduc S, Bar-Or O, Newland H, Taras HL, Cimino DA, McGrath JW, Murray RD, Yankus WA, Young TL, Fleming M, Glendon M, Harrison-Jones L, Newberry JL, Pattishall E, Vernon M, Wolfe L, Li S. Organized sports for children and preadolescents. Pediatrics 2001; 107:1459-62. [PMID: 11389277 DOI: 10.1542/peds.107.6.1459] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Participation in organized sports provides an opportunity for young people to increase their physical activity and develop physical and social skills. However, when the demands and expectations of organized sports exceed the maturation and readiness of the participant, the positive aspects of participation can be negated. The nature of parental or adult involvement can also influence the degree to which participation in organized sports is a positive experience for preadolescents. This updates a previous policy statement on athletics for preadolescents and incorporates guidelines for sports participation for preschool children. Recommendations are offered on how pediatricians can help determine a child's readiness to participate, how risks can be minimized, and how child-oriented goals can be maximized.
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Abstract
The initial identification in 1993 of hantavirus pulmonary syndrome as a novel, highly fatal respiratory illness among American Indians in the southwestern USA in 1993 opened the window to the recognition of a well-established pan-American zoonosis with a myriad of causative viruses and rodent vectors, although all are New World hantaviruses among New World sigmodontine rodents. The clinical spectrum of symptoms has also been expanded to include asymptomatic infection through to fulminant hemorrhagic fever. Although the use of ribavirin, an antiviral drug, was disappointing in an early, open-labeled trial, early detection and supportive care is much better refined. However, much work remains in probing the pathogenesis of this syndrome to help define and explore therapeutic options and the mechanism of person-to-person transmission with Andes virus, one of the viruses that cause hantavirus pulmonary syndrome. Current remote sensing efforts and longitudinal ecologic investigations need to be expanded in order to focus prevention efforts better.
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Affiliation(s)
- A S Khan
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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26
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Chen JG, Ullah H, Young JC, Sussman MR, Jones AM. ABP1 is required for organized cell elongation and division in Arabidopsis embryogenesis. Genes Dev 2001; 15:902-11. [PMID: 11297513 PMCID: PMC312669 DOI: 10.1101/gad.866201] [Citation(s) in RCA: 268] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2000] [Accepted: 01/29/2001] [Indexed: 11/25/2022]
Abstract
To directly address the function of a putative auxin receptor designated ABP1, a reverse genetic approach was taken to identify and characterize ABP1 mutant alleles in Arabidopsis. A homozygous null mutation in ABP1 confers embryo lethality. Null mutant embryos develop normally until the early stages of the globular embryo but are unable to make the transition to a bilaterally symmetrical structure because cells fail to elongate. Cell division was also aberrant both in the suspensor and embryo proper. Antisense suppression of ABP1 in tobacco cells causes slow proliferation and eliminates auxin-induced cell elongation and reduces cell division. The complete lack of auxin-inducible elongation in individual cells confirms the results observed in embryos, indicates a cell autonomous function, and, taken together with biochemical evidence that ABP1 binds auxins, suggests that ABP1 mediates auxin-induced cell elongation and, directly or indirectly, cell division.
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Affiliation(s)
- J G Chen
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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27
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Abstract
Megakaryocytopoiesis is a complex biological process involving a series of cellular events that begins with the pluripotent hematopoietic stem cell and ultimately results in the biogenesis of platelets. A hierarchy of megakaryocyte (MK) progenitor cells has been previously defined based upon studies of in vitro megakaryocytopoiesis. Ontogeny-related changes in MK progenitor cells were analyzed in order to further define this cellular hierarchy. Unifocal colony-forming unit-megakaryocyte (CFU-MK)-derived colonies cloned from fetal bone marrow (FBM) formed after fewer days of in vitro culture and were 2.6-fold larger than those colonies cloned from adult bone marrow (ABM). The frequency of CFU-MK-derived colonies cloned from ABM was significantly greater. MK colonies, however, cloned from FBM morphologically consisted of both pure MK colonies and mixed colonies containing MKs, in which a core of CD41- cells were surrounded by CD41+ MKs. Large colonies resembling the primitive BFU-MK also were assayed from both FBM and ABM. These BFU-MK-derived colonies appeared after fewer days of incubation when FBM was assayed, compared to ABM, but at a significantly lower frequency. In addition, large unifocal MK colonies consisting of >300 cells (300-1000) appeared from cells cloned from fetal, but not adult, marrow. This type of colony represents a unique type of MK progenitor cell, termed the high-proliferative-potential cell-MK. Such colonies represent the progeny of the most primitive human MK progenitor cell identified to date. We also attempted to investigate the process of commitment of stem cells to the MK lineage. We explored the actions of thrombopoietin (TPO) on primitive hematopoietic cells in order to gain an understanding of stem cell commitment. CD34+ Thy-1+ Lin- marrow cells, which are enriched for pluripotent hematopoietic stem cells, were shown to express c-Mpl by the polymerase chain reaction. In addition, TPO alone was capable of inducing CD34+ Thy-1+ Lin- cells after two to three weeks to produce progeny composed entirely of MKs. These studies indicate that TPO has a profound effect on hematopoietic stem cells, and that the hierarchy of MK progenitor cells begins with the pluripotent hematopoietic stem cell.
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Affiliation(s)
- R Hoffman
- Hematology-Oncology Section, University of Illinois College of Medicine, Chicago 60607, USA
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28
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Abstract
The sequencing of the Arabidopsis plant genome is providing a fuller understanding of the number and types of plant genes. However, in most cases we do not know which genes are responsible for specific metabolic and signal transduction pathways. Analysis of gene function is also often confounded by the presence of multiple isoforms of the gene of interest. Recent advances in PCR-based reverse genetic techniques have allowed the search for plants carrying T-DNA insertions in any gene of interest. Here we report preliminary screening results from an ordered population of nearly 60,470 independently derived T-DNA lines. Degenerate PCR primers were used on large DNA pools (n = 2,025 T-DNA lines) to screen for more than one gene family member at a time. Methods are presented that facilitated the identification and isolation of isoform-specific mutants in almost all members of the Arabidopsis H(+)-proton ATPase gene family. Multiple mutant alleles were found for several isoforms.
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Affiliation(s)
- J C Young
- Biology Department, Western Washington University, Bellingham, Washington 98225, USA
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29
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Guevara JP, Young JC, Mueller BA. Do protective factors reduce the risk of hospitalization in infants of teenaged mothers? Arch Pediatr Adolesc Med 2001; 155:66-72. [PMID: 11177065 DOI: 10.1001/archpedi.155.1.66] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To determine the risk of hospitalization associated with prenatal care use and indicators of socioeconomic status and social support among infants of teenage mothers. DESIGN Population-based case-control study. SETTING Nonfederal hospitals in Washington State. PARTICIPANTS Infants born from 1987 to 1995 to mothers younger than 20 years were identified using linked birth certificate-state hospital discharge data. Cases consisted of 8052 infants who were hospitalized during the first year of life at least 2 days after birth hospitalization discharge. An equal number of controls, frequency matched on birth year and maternal age group, were randomly sampled from among nonhospitalized infants. MAIN OUTCOME MEASURE Hospitalization in the first year of life. RESULTS Infants with a father listed on the birth certificate or whose mothers had commercial health insurance had a decreased risk of hospitalization (adjusted odds ratios, 0.91 and 0.78, respectively; 95% confidence intervals, 0.83-0.99 and 0.71-0.85, respectively). Participation in state-funded pregnancy programs, adequacy of prenatal care, or marital status did not affect the risk of hospitalization, except among infants whose mothers received more than adequate prenatal care (adjusted odds ratio, 1.15; 95% confidence interval, 1.03-1.29). CONCLUSION Our results suggest that teenaged mothers who list a father on the birth certificate or who have insurance, indicative of higher socioeconomic status, may have a reduced risk of hospitalization for their infants. Teenaged mothers who receive more than adequate prenatal care may have pregnancy complications that place their infants at increased risk of hospitalization. The effect of these protective factors should be clarified in future studies.
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Affiliation(s)
- J P Guevara
- Division of General Pediatrics, Children's Hospital of Philadelphia, 34th and Civic Center Boulevard, Philadelphia, PA 19104, USA
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Gottwald JR, Krysan PJ, Young JC, Evert RF, Sussman MR. Genetic evidence for the in planta role of phloem-specific plasma membrane sucrose transporters. Proc Natl Acad Sci U S A 2000; 97:13979-84. [PMID: 11087840 PMCID: PMC17686 DOI: 10.1073/pnas.250473797] [Citation(s) in RCA: 279] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A major question in plant physiology is how the large amount of sucrose made in leaves is transported to the rest of the plant. Although physiological, biochemical, and anatomical investigations have been performed in this field, to date there have been very few genetic studies. Using a reverse genetic screen, we have identified mutant Arabidopsis plants containing transferred DNA insertions in the gene encoding a phloem-specific sucrose transporter, SUC2. SUC2 is thought to function in loading sugar from the apoplast into the conducting sieve tubes. In the homozygous state, these mutations resulted in stunted growth, retarded development, and sterility. The source leaves of mutant plants contained a great excess of starch, and radiolabeled sugar failed to be transported efficiently to roots and inflorescences. These data provide genetic proof that apoplastic phloem loading is critical for growth, development, and reproduction in Arabidopsis and that SUC2 is at least partially responsible for this step.
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Affiliation(s)
- J R Gottwald
- Biotechnology Center and Department of Botany, University of Wisconsin, Madison, WI 53706, USA
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Sussman MR, Amasino RM, Young JC, Krysan PJ, Austin-Phillips S. The Arabidopsis knockout facility at the University of Wisconsin-Madison. Plant Physiol 2000; 124:1465-7. [PMID: 11115860 PMCID: PMC1539297 DOI: 10.1104/pp.124.4.1465] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- M R Sussman
- Biotechnology Center, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Abstract
The molecular chaperone Hsp90 binds and hydrolyses ATP, but how this ATPase activity regulates the interaction of Hsp90 with a polypeptide substrate is not yet understood. Using the glucocorticoid receptor ligand binding domain as a substrate, we show that dissociation of Hsp90 from bound polypeptide depends on the Hsp90 ATPase and is blocked by geldanamycin, a specific ATPase inhibitor. The co-chaperone p23 greatly stimulates Hsp90 substrate release with ATP, but not with the non-hydrolysable nucleotides ATPgammaS or AMP-PNP. Point mutants of Hsp90 with progressively lower ATPase rates are progressively slower in ATP-dependent substrate release but are still regulated by p23. In contrast, ATPase-inactive Hsp90 mutants release substrate poorly and show no p23 effect. These results outline an ATP-driven cycle of substrate binding and release for Hsp90 which differs from that of other ATP-driven chaperones. Conversion of the ATP state of Hsp90 to the ADP state through hydrolysis is required for efficient release of substrate polypeptide. p23 couples the ATPase activity to polypeptide dissociation and thus can function as a substrate release factor for Hsp90.
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Affiliation(s)
- J C Young
- Cellular Biochemistry, Max Planck Institute for Biochemistry, Am Klopferspitz 18a, 82152 Martinsried, Germany.
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Iannello RC, Gould JA, Young JC, Giudice A, Medcalf R, Kola I. Methylation-dependent silencing of the testis-specific Pdha-2 basal promoter occurs through selective targeting of an activating transcription factor/cAMP-responsive element-binding site. J Biol Chem 2000; 275:19603-8. [PMID: 10766751 DOI: 10.1074/jbc.m001867200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we demonstrate that methylation-dependent repression of the Pdha-2 core promoter is mediated regionally through a consensus activating transcription factor/cAMP-responsive element-binding site located between nucleotides -54 and -62 upstream of the major transcriptional start site. Targeting of the CpG dinucleotide within this cis-element significantly disrupts the ability of this basal promoter to activate gene expression in vitro and completely abolishes promoter activity in vivo. DNase I footprinting experiments indicated that availability of the nuclear factor(s) binding this element is limiting in sexually immature mouse testis, and as such, these factors may play an important role in the coordinate activation of early spermatogenic gene expression. Interestingly, CpG dinucleotides associated with the hypersensitive region flanking the activating transcription factor/cAMP-responsive element-binding site appear to confer some conformational structure on the promoter since mutations at these specific CpG dinucleotides result in elevated basal levels of transcription. This raises the possibility of a potential bifunctional role for CpG dinucleotides in either methylation-dependent or -independent processes. Our data support the notion that hypomethylation and transcription factor recruitment are necessary events that precede gene activation at the early stages of spermatogenesis.
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Affiliation(s)
- R C Iannello
- Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia.
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Young JC, Hansen GR, Graves TK, Deasy MP, Humphreys JG, Fritz CL, Gorham KL, Khan AS, Ksiazek TG, Metzger KB, Peters CJ. The incubation period of hantavirus pulmonary syndrome. Am J Trop Med Hyg 2000; 62:714-7. [PMID: 11304061 DOI: 10.4269/ajtmh.2000.62.714] [Citation(s) in RCA: 67] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In 1993 Sin Nombre virus was recognized as the cause of hantavirus pulmonary syndrome (HPS) and the deer mouse (Peromyscus maniculatus) was identified as the reservoir host. Surveillance by the Centers for Disease Control and Prevention and state health departments includes investigation to determine the likely site(s) and activities that led to infection, an environmental assessment of the home and workplace, and possibly rodent trappings at these sites. As of December 31, 1998, there were 200 confirmed cases from 30 states (43% case-fatality ratio). The national HPS case registry was examined to determine the incubation period of HPS. Review of 11 case-patients with well-defined and isolated exposure to rodents suggests that the incubation period of HPS is 9 to 33 days, with a median of 14-17 days. Case investigations allow a better understanding of the incubation time of HPS and may define high-risk behaviors that can be targeted for intervention.
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Affiliation(s)
- J C Young
- Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30329-4018, USA.
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Nagpal P, Walker LM, Young JC, Sonawala A, Timpte C, Estelle M, Reed JW. AXR2 encodes a member of the Aux/IAA protein family. Plant Physiol 2000; 123:563-74. [PMID: 10859186 PMCID: PMC59024 DOI: 10.1104/pp.123.2.563] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/1999] [Accepted: 02/26/2000] [Indexed: 05/17/2023]
Abstract
The dominant gain-of-function axr2-1 mutation of Arabidopsis causes agravitropic root and shoot growth, a short hypocotyl and stem, and auxin-resistant root growth. We have cloned the AXR2 gene using a map-based approach, and find that it is the same as IAA7, a member of the IAA (indole-3-acetic acid) family of auxin-inducible genes. The axr2-1 mutation changes a single amino acid in conserved domain II of AXR2/IAA7. We isolated loss-of-function mutations in AXR2/IAA7 as intragenic suppressors of axr2-1 or in a screen for insertion mutations in IAA genes. A null mutant has a slightly longer hypocotyl than wild-type plants, indicating that AXR2/IAA7 controls development in light-grown seedlings, perhaps in concert with other gene products. Dark-grown axr2-1 mutant plants have short hypocotyls and make leaves, suggesting that activation of AXR2/IAA7 is sufficient to induce morphological responses normally elicited by light. Previously described semidominant mutations in two other Arabidopsis IAA genes cause some of the same phenotypes as axr2-1, but also cause distinct phenotypes. These results illustrate functional differences among members of the Arabidopsis IAA gene family.
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Affiliation(s)
- P Nagpal
- Department of Biology, University of North Carolina at Chapel Hill, 27599-3280, USA
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Khandaker NR, Young JC. Effect of culture acclimation on the kinetics of aldicarb insecticide degradation under methanogenic conditions. J Agric Food Chem 2000; 48:1411-1416. [PMID: 10775406 DOI: 10.1021/jf990427t] [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] [Indexed: 05/23/2023]
Abstract
This study reports on the kinetics of aldicarb transformation under methanogenic conditions using batch reactors containing acclimated and unacclimated cultures under controlled conditions. Culture acclimation was accomplished by exposing anaerobic microorganisms maintained in a semi-batch reactor to low concentrations of aldicarb. Results of the kinetic studies showed that in an anaerobic system aldicarb is converted to aldicarb nitrile by the hydrolytic pathway. Analysis of the hydrolysis/dehydration rate constants showed that anaerobic cultures enhanced the rate of conversion of aldicarb by 4-fold for acclimated cultures and by 2-fold for unacclimated cultures compared to the rate of abiotic hydrolysis (p < 0.05). Only the acclimated cultures were able to further mineralize the reaction intermediate aldicarb nitrile. Michaelis-Menten and Monod kinetics adequately defined the aldicarb nitrile degradation.
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Affiliation(s)
- N R Khandaker
- Department of Civil and Environmental Engineering, 4190 Bell Engineering Center, University of Arkansas, Fayetteville, Arkansas 72701, USA
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Affiliation(s)
- P J Krysan
- Biotechnology Center, University of Wisconsin, 425 Henry Mall, Madison, Wisconsin 53706, USA
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Reid LM, Nicol RW, Ouellet T, Savard M, Miller JD, Young JC, Stewart DW, Schaafsma AW. Interaction of Fusarium graminearum and F. moniliforme in Maize Ears: Disease Progress, Fungal Biomass, and Mycotoxin Accumulation. Phytopathology 1999; 89:1028-1037. [PMID: 18944658 DOI: 10.1094/phyto.1999.89.11.1028] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT To investigate the interaction between two major ear-rotting pathogens, maize ears were inoculated with either Fusarium graminearum, F. moniliforme, or an equal mixture of the two. Silk and kernel tissues were periodically harvested throughout the growing season so that a time course of the experimental variables (disease severity, ergosterol content, fungal DNA content, and mycotoxin concentration) could be recorded. Over the 3 years tested (1992 to 1994), the highest levels of disease and ergosterol were found in the F. graminearum treatment, followed by the mixture treatment (F. graminearum plus F. moniliforme) and, finally, the F. moniliforme treatment. Kernel ergosterol content and disease rating were correlated for both pathogens, but the highest correlation coefficients were obtained in the F. graminearum treatment. The DNA analysis revealed that, in the mixed inoculum, F. moniliforme had a greater growth rate than did F. graminearum. In 1994, appreciable F. moniliforme from natural inoculum was found in the F. graminearum treatment. Fumonisin B(1) levels did not differ between the F. moniliforme treatment and the mixed inoculum treatment. The effect of temperature on the growth rate of the two species explained some of the field results, with temperatures in the silks being more favorable to F. moniliforme. Data on the growth rate on silks obtained by the incorporation of radiolabeled precursor to ergosterol demonstrated that F. graminearum was able to grow well at 26 to 28 degrees C, whereas F. moniliforme grew well over a broader range, including at higher temperatures.
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Harris LJ, Desjardins AE, Plattner RD, Nicholson P, Butler G, Young JC, Weston G, Proctor RH, Hohn TM. Possible Role of Trichothecene Mycotoxins in Virulence of Fusarium graminearum on Maize. Plant Dis 1999; 83:954-960. [PMID: 30841080 DOI: 10.1094/pdis.1999.83.10.954] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Trichothecene-producing and -nonproducing Fusarium graminearum strains were tested for their ability to cause Gibberella ear rot in field trials at two locations-Ottawa, Ontario, and Peoria, Illinois-in 1996. Maize ears were inoculated with wild-type or transgenic F. graminearum strains in which the trichothecene biosynthetic pathway had been disabled by the specific disruption of the trichodiene synthase gene and with a derivative revertant strain in which trichothecene production had been restored through recombination. A silk channel inoculation method was employed at both locations. In addition, a kernel puncture inoculation method was used at the Ontario location. Harvested maize ears were analyzed for visual disease severity, grain yield, deoxynivalenol (DON) concentration, and fungal biomass by quantitative polymerase chain reaction (PCR) and/or ergosterol quantitation. There was a significant correlation (r= 0.86) between data obtained from the two different methods of quantifying fungal biomass. The trichothecene-nonproducing strains were still pathogenic but appeared less virulent on maize than the trichothecene-producing progenitor and revertant strains, as assayed by most parameters. This suggests that the trichothecenes may act as virulence factors to enhance the spread of F. graminearum on maize.
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Affiliation(s)
- L J Harris
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6 Canada
| | - A E Desjardins
- Mycotoxin Research, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL 61604
| | - R D Plattner
- Mycotoxin Research, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL 61604
| | - P Nicholson
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
| | - G Butler
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6 Canada
| | - J C Young
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6 Canada
| | - G Weston
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
| | - R H Proctor
- Mycotoxin Research, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL 61604
| | - T M Hohn
- Mycotoxin Research, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL 61604
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Balon TW, Jasman AP, Young JC. Effects of chronic N(omega)-nitro-L-arginine methyl ester administration on glucose tolerance and skeletal muscle glucose transport in the rat. Nitric Oxide 1999; 3:312-20. [PMID: 10444370 DOI: 10.1006/niox.1999.0235] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [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: 11/22/2022]
Abstract
It has been suggested that nitric oxide (NO) is a key regulator of carbohydrate metabolism in skeletal muscle. The present study was undertaken to examine the effects of chronic in vivo competitive antagonism of NO synthase (NOS) by the administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) in the drinking water (1 mg/ml) for 14 days on glucose tolerance and skeletal muscle glucose transport in rats. Oral glucose tolerance tests (OGTT) revealed an impaired glucose tolerance in the L-NAME-treated rats as reflected by the area under the glucose curve (4675 +/- 514 mg% x 120 min (control) vs 6653 +/- 571 mg% x 120 min (L-NAME treated); P < 0.03). While a large rise in plasma insulin concentration was present in the control rats (0.87 +/- 0.34 ng/ml, P < 0.001) during the first 15 min of the OGTT, rises in plasma insulin concentration were absent in the L-NAME-treated rats (0.18 +/- 0.13 ng/ml, P = NS). Intravenous glucose tolerance tests confirmed an impaired insulin secretion in the L-NAME-treated rats. In contrast, insulin-stimulated 2-deoxyglucose transport was enhanced (P < 0.03) by chronic NOS inhibition (5.29 +/- 0.83 nmol/g/min) compared to control rats (2.21 +/- 0.90 nmol/g/min). Plasma sodium concentrations were lower and plasma potassium concentrations were higher in the L-NAME-treated group, indicating an impaired electrolyte status. We conclude that chronic in vivo administration of a NOS inhibitor, while not impairing basal parameters of carbohydrate metabolism, may manifest different responses than acute exposure to the same agent in vitro.
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Affiliation(s)
- T W Balon
- Department of Diabetes, Endocrinology and Metabolism, Duarte, California 91010-3000, USA.
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Young JC, Lin K, Hansteen G, Travis M, Murray LJ, Jaing L, Scollay R, Hill BL. CD34+ cells from mobilized peripheral blood retain fetal bone marrow repopulating capacity within the Thy-1+ subset following cell division ex vivo. Exp Hematol 1999; 27:994-1003. [PMID: 10378888 DOI: 10.1016/s0301-472x(99)00030-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [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
Ex vivo cell cycling of hematopoietic stem cells (HSC), a subset of primitive hematopoietic progenitors (PHP) with engrafting capacity, is required for transduction with retroviral vectors and to increase transplantable HSC numbers. However, induction of division of HSC ex vivo also may lead to differentiation and loss of in vivo marrow repopulating potential. We evaluated mobilized peripheral blood (MPB) PHP for maintenance of stem cell function after ex vivo culture under conditions that we show can induce cycling of a majority of PHP with minimal differentiation. The following methods were combined: cell labeling with the division tracking dye carboxyfluorescein-diacetate succinimidylester (CFSE), analysis of primitive cell surface marker expression, an ex vivo PHP assay, and an in vivo marrow repopulating assay. MPB-purified CD34+ Thy-1+ cells were labeled with CFSE dye and cultured for 112 hours in serum-deprived medium in the presence of the cytokine combinations of thrombopoietin (TPO), flt3 ligand (FL), and c-kit ligand (KL), or TPO, FL, and interleukin 6 (IL-6). Both cytokine combinations supported division of greater than 95% of cells within 112 hours with an average 2.1-fold (TPO, FL, KL) or 1.3-fold (TPO, FL, IL-6) increase in total cell numbers. An average of 21.6% (TPO, FL, KL) and 27.4% (TPO, FL, IL-6) of the divided cells still expressed the Thy-1 marker after 112 hours. Functional assays were performed to compare cultured and uncultured cells. CD34+ Thy-1+ CFSElo (post division) cells showed maintenance of cobblestone area-forming cell (CAFC) frequency (a mean of 1/9.0) relative to the starting population of uncultured CD34+ Thy-1+ cells (a mean of 1/8.4). In contrast, CD34+ cells that had lost Thy-1 expression during culture (CD34+ Thy-1 CFSElo) showed a mean 5.8-fold reduction in CAFC frequency (a mean of 1/52.5). Only the Thy-1-expressing fraction of cells post culture could engraft in vivo in the SCID-hu bone assay. Because the majority of HSC functional activity post culture was found in the CD34+ Thy-1+ fraction, we focused on this fraction for subsequent analysis. CFSE labeling allows segregation and purification by flow cytometry of cells having undergone discrete numbers of divisions during culture. Very few cells that divided more than four times in culture still expressed Thy-1. Cells that retained expression of Thy-1 during culture retained CAFC activity relative to fresh CD34+ Thy-1+ cells, after undergoing at least two divisions. CAFC frequency decreased after four divisions in culture with TPO, FL, and KL or after three divisions in TPO, FL, and IL-6. We then compared populations of Thy-1+ cells that had undergone sequential numbers of divisions in culture for their ability to engraft in the SCID-hu bone assay. Engrafting ability was retained throughout four divisions in both cytokine combinations. These data demonstrate that primitive MPB CD34+ cells maintain HSC function coincident with Thy-1 expression while undergoing two to four divisions under these culture conditions. Essentially all CD34+ Thy-1+ cells divided under the conditions tested, promoting susceptibility to retroviral transduction.
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Affiliation(s)
- J C Young
- SyStemix Inc. (a Novartis company), Palo Alto, CA, USA.
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Murray LJ, Young JC, Osborne LJ, Luens KM, Scollay R, Hill BL. Thrombopoietin, flt3, and kit ligands together suppress apoptosis of human mobilized CD34+ cells and recruit primitive CD34+ Thy-1+ cells into rapid division. Exp Hematol 1999; 27:1019-28. [PMID: 10378891 DOI: 10.1016/s0301-472x(99)00031-4] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Various combinations of cytokines have profoundly different effects on inhibition of apoptosis and stimulation of self-renewal division of hematopoietic stem cells (HSC) in short-term, ex vivo culture. Our goal was to quantitate expansion of cells with a primitive CD34+ Thy-1+ phenotype, as well as cell cycling, division history, differentiation, and apoptosis of CD34+ cells enriched from normal donor mobilized peripheral blood (MPB) cells. The balance of these parameters determines the net number of transplantable HSC produced in ex vivo cultures. Comparing several different combinations of cytokines added to 90-hour cultures of MPB CD34 cells, thrombopoietin (TPO), flt3 ligand (FL), and c-kit ligand (KL) gave the best result, with the lowest percentage of apoptotic cells and a mean 1.2-fold increase in the number of CD34+ Thy-1+ cells. A combination of interleukin 3 (IL-3), interleukin 6 (IL-6), and leukemia inhibitory factor (LIF) gave the worst outcome, including a decrease of CD34+ Thy-1+ cell number to a mean of 30% of the starting cell number. Cell division history was tracked using the dye 5-(and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE). Division of CD34+ Thy-1+ cells was faster and more synchronous in TPO, FL, and KL than in IL-3, IL-6, and LIF, which left a significant proportion of CD34+ cells undivided. Such detailed analyses of short-term, ex vivo cultures generated "replication scores," which allowed prediction of a sixfold improvement of the efficiency of gene transduction of primitive hematopoietic progenitors from MPB, using TPO, FL, and KL to replace IL-3, IL-6, and LIF. Analysis of retroviral transduction efficiency confirmed the increase of transgene expression from MPB primitive hematopoietic progenitors assayed after stromal culture was fivefold, validating the usefulness of multiparameter analysis of short-term cultures for survival and replication of CD34+ Thy-1+ cells.
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Affiliation(s)
- L J Murray
- SyStemix (a Novartis Company), Cell Therapy Research, Palo Alto, CA 94304, USA.
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Abstract
PURPOSE In two separate but identical studies, the effect of vitamin B-6 supplementation was examined on plasma energy substrates, catecholamines, and 13 amino acid concentrations during exercise. METHODS Eleven trained men performed two separate exhaustive exercise tests at 71.0+/-4.6% VO2max during two separate 9-d controlled diet periods. Exercise test 1 (T1C) occurred following a control diet, and test 2 (T2B6) occurred following a vitamin B-6 supplemented diet (20 mg PN.d(-1)). Blood was drawn pre, during (60 min), post, and post-60 min of exercise, and plasma was analyzed for glucose, lactate, glycerol, free fatty acids (FFA), catecholamines (N = 5), and amino acids (N = 5). RESULTS Mean FFA concentrations changed over time in both tests (P < 0.001) and were lower in T2B6 compared to T1C at pre (P = 0.03), during (P = 0.05), and post-60 min (P = 0.04) of exercise. Mean lactate, glycerol, and catecholamine concentrations only changed over time (P < 0.0001). The only significant changes in amino acid concentrations were for lower tyrosine (P = 0.007) and methionine (P = 0.03) concentrations in T2B6 relative to TIC at post-60 min of exercise and postexercise, respectively. No differences were observed in exercise times to exhaustion between TIC (108+32.6 min) and T2B6 (109+51.2 min). CONCLUSIONS These results indicate that vitamin B-6 supplementation can alter plasma FFA and amino acid concentrations during exhaustive endurance exercise without affecting endurance.
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Affiliation(s)
- R S Virk
- Department of Nutrition and Food Management, Oregon State University, Corvallis 97331, USA
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Kitsutani PT, Denton RW, Fritz CL, Murray RA, Todd RL, Pape WJ, Wyatt Frampton J, Young JC, Khan AS, Peters CJ, Ksiazek TG. Acute Sin Nombre hantavirus infection without pulmonary syndrome, United States. Emerg Infect Dis 1999; 5:701-5. [PMID: 10511527 PMCID: PMC2627725 DOI: 10.3201/eid0505.990512] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hantavirus pulmonary syndrome (HPS) occurs in most infections with Sin Nombre virus and other North American hantaviruses. We report five cases of acute hantavirus infection that did not fit the HPS case definition. The patients had characteristic prodromal symptoms without severe pulmonary involvement. These cases suggest that surveillance for HPS may need to be expanded.
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Affiliation(s)
- P T Kitsutani
- Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Young JC, Wu S, Travis M, Luens KM, Osborne L, Scollay R, Hill B. Quantitation of the proliferative potential of highly enriched human primitive hematopoietic progenitor cells using a stroma-free limiting dilution assay with automated scoring. Cytotherapy 1999; 1:147-56. [PMID: 19746592 DOI: 10.1080/0032472031000141253] [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: 10/26/2022]
Abstract
BACKGROUND Increasing use of phenotypically-enriched stem cell populations for clinical hematopoietic transplants has led to an urgent demand for a reliable, rapid and simple functional assay which would provide an estimation of the reconstituting potential of cells prior to transplantation. METHODS We have developed a 2-week quantitative, stroma-free assay to measure the frequency of primitive progenitors within hematopoietic cell samples. This relatively short-term assay provides frequency information which correlates with that measured by a 5-week stroma-dependent CAFC assay. Cells with the phenotype CD34+Thy-1+ were purified by fluorescence-activated cell sorting from peripheral blood apheresis products of multiple myeloma patients mobilized with cytoxan and GM-CSF. CD34+Thy-1+ cells were plated at limiting dilution into microtiter wells and cultured in an Iscove's based serum-deprived culture medium, supplemented with the cytokines, interleukin (IL)-3, IL-6, G-CSF, Flk2/Flt3 ligand (FL) and Kit ligand (KL). After 2 weeks, cell proliferation in individual wells was quantified by microscopy and bright-field imaging, or by using a fluorescent nucleic acid-binding dye and fluorimetry. Poisson statistics were used to calculate the frequency of wells containing cells with high proliferative potential (wells containing > or = 500 cells). RESULTS Progenitor cell frequencies generated using this assay were compared by linear regression analysis to those generated from 32 parallel CAFC and CFU-C assays performed on the same patient samples. Correlations were r = 0.80, r2 = 0.65, and r = 0.76, r2 = 0.58, respectively; these correlations were highly significant (p < 10(-7)). DISCUSSION This limiting dilution assay should more directly quantitate the potential of primitive hematopoietic cells than a CFU-C assay. It also has advantages over both the CAFC and the CFU-C assay, in that scoring has been automated, making it simple, rapid, and objective compared with manual cobblestone area or colony counting. The described limiting dilution assay may provide a useful alternative to assays currently used to evaluate the viability and proliferative potential of purified hematopoietic cells intended for transplant.
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Young JC, Gould JA, Kola I, Iannello RC. Review: Pdha-2, past and present. J Exp Zool 1998; 282:231-8. [PMID: 9723179] [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] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pyruvate dehydrogenase (PDH) is a multiunit enzymatic complex essential for the process of generating cellular energy. One of the most important of its subunits is the E1 alpha subunit. Perturbations in the expression of this subunit lead to reduced or lost function of the PDH complex as a whole, resulting in a loss of ATP production. The consequence of such perturbations can lead to neurological abnormalities, lactic acidosis, and in males, death. Pdha-2 codes for the mouse testis isoform of the E1 alpha subunit and maps to chromosome 19 (chromosome 4 in humans). This is a fortuitous evolutionary development because the somatic isoform of the E1 alpha subunit is linked to the X-chromosome, which is not only inactivated early in spermatogenesis but is represented in only half of the haploid spermatid population. Consequently, activation of the testis-specific E1 alpha subunit is essential for the progression of spermatogenesis. Despite its importance, the molecular mechanisms governing the tight tissue- and temporal-specific regulation of Pdha-2 have, until recently, remained poorly understood. In this review, we describe our current understanding of the transcriptional regulation of Pdha-2 and propose potential mechanisms that may play a role in this process.
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Affiliation(s)
- J C Young
- Molecular Genetics and Development Laboratory, Monash University, Clayton, Victoria, Australia
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Abstract
The molecular chaperone hsp90 in the eukaryotic cytosol interacts with a variety of protein cofactors. Several of these cofactors have protein domains containing tetratricopeptide repeat (TPR) motifs, which mediate binding to hsp90. Using a yeast two-hybrid screen, the 12-kDa C-terminal domain of human hsp90alpha (C90) was found to mediate the interaction of hsp90 with TPR-containing sequences from the hsp90 cofactors FKBP51/54 and FKBP52. In addition, the mitochondrial outer membrane protein hTOM34p was identified as a TPR-containing putative partner protein of hsp90. In experiments with purified proteins, the TPR-containing cofactor p60 (Hop) was shown to form stable complexes with hsp90. A deletion mutant of hsp90 lacking the C90 domain was unable to bind p60, whereas deletion of the approximately 25-kDa N-terminal domain of hsp90 did not affect complex formation. Both p60 and FKBP52 bound specifically to the C90 domain fused to glutathione S-transferase and competed with each other for binding. In reticulocyte lysate, the C90 fusion protein recognized the TPR proteins p60, FKBP52, and Cyp40. Thus, our results identify the C90 domain as the specific binding site for a set of hsp90 cofactors having TPR domains.
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Affiliation(s)
- J C Young
- Department of Cellular Biochemistry, Max-Planck-Institut für Biochemie, Am Klopferspitz 18A, D-82152 Martinsried, Germany
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48
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Abstract
Proton pumps (H+-ATPases) are the primary active transport systems in the plasma membrane of higher plant cells. These enzymes are encoded by a large gene family expressed throughout the plant, with specific isoforms directed to various specialized cells. While their involvement in membrane energetics has been suggested by a large body of biochemical and physiological studies, a genetic analysis of their role in plants has not yet been performed. We report here that mutant Arabidopsis thaliana plants containing a phloem-specific transgene encoding a plasma membrane H+-ATPase with an altered carboxy terminus show improved growth at low pH during seedling development. These observations provide the first genetic evidence for a role of the plasma membrane H+-ATPase in cytoplasmic pH homeostasis in plants.
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Affiliation(s)
- J C Young
- Biotechnology Center, University of Wisconsin, Madison, Wisconsin 53706, USA
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Abstract
Since the initial description in 1993 of hantavirus pulmonary syndrome and its novel aetiological agent, Sin Nombre virus, our knowledge of the epidemiology of New World hantaviruses has continued to evolve. After the identifying outbreak in the southwestern US, four hantaviruses have been identified in North America with specific rodent hosts and associated with a number of sporadic cases. This stability of case recognition in North America is in contrast to the multiple outbreaks and endemic cases in South America. Despite a plethora of New World hantaviruses and new evidence of person-to-person transmission, the ecological and personal determinants of this human infection remain a mystery.
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Affiliation(s)
- J C Young
- Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329-4018, USA
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50
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Abstract
Hsp90 is an abundant and constitutively expressed stress protein and molecular chaperone. Here we dissected human hsp90 into three major domains to identify the putative chaperone site at which hsp90 binds unfolded polypeptide. Surprisingly, both the N-terminal and the C-terminal domain of hsp90 prevent the aggregation of denatured polypeptides. The chaperone activity of the N-domain is inhibited by geldanamycin, a specific inhibitor of hsp90-mediated protein refolding. While both domains suppress protein aggregation, only the C-domain binds an antigenic peptide derived from VSV G. Based on these results, hsp90 may be the first chaperone to contain two independent chaperone sites with differential specificity.
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Affiliation(s)
- J C Young
- Cellular Biochemistry, Max-Planck-Institut für Biochemie, Martinsried, Germany
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