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Maximov AV, Shaw JG, Palastro JP. Nonlinear transmission of laser light through coronal plasma due to self-induced incoherence. Phys Rev E 2020; 102:023205. [PMID: 32942510 DOI: 10.1103/physreve.102.023205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 07/08/2020] [Indexed: 11/07/2022]
Abstract
The success of direct laser-driven inertial confinement fusion (ICF) relies critically on the efficient coupling of laser light to plasma. At ignition scale, the absolute stimulated Raman scattering (SRS) instability can severely inhibit this coupling by redirecting and strongly depleting laser light. This article describes a new dynamic saturation regime of the absolute SRS instability near one-quarter of the critical density. The saturation occurs when spatiotemporal ion-acoustic fluctuations in the plasma density detune the instability resonance. The dynamic saturation mitigates the strong depletion of laser light and enhances its transmission through the instability region, explaining the coupling of laser light to ICF targets at higher plasma densities.
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Affiliation(s)
- A V Maximov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J P Palastro
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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2
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Follett RK, Shaw JG, Myatt JF, Froula DH, Palastro JP. Multibeam absolute stimulated Raman scattering and two-plasmon decay. Phys Rev E 2020; 101:043214. [PMID: 32422790 DOI: 10.1103/physreve.101.043214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/08/2020] [Indexed: 11/07/2022]
Abstract
Multibeam absolute instability thresholds for stimulated Raman scattering (SRS) and two-plasmon decay (TPD) are calculated in three dimensions for conditions relevant to direct-drive inertial confinement fusion experiments on the OMEGA laser and at the National Ignition Facility (NIF). Although multibeam effects are found to be significant for both instabilities, SRS is found to have less efficient multibeam coupling than TPD. The results are consistent with the observation of a TPD-dominated regime on the OMEGA laser and a SRS-dominated regime on the NIF despite the single-beam SRS threshold being lower than the single-beam TPD threshold on both facilities. The minimum instability threshold for NIF plasma parameters occurs for SRS near quarter-critical densities with a shared electromagnetic wave propagating along the beam axis.
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Affiliation(s)
- R K Follett
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester New York 14623, USA
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester New York 14623, USA
| | - J F Myatt
- Department of Electrical and Computer Engineering University of Alberta, 9211 116th St. NW, Edmonton, Alberta T6G 1H9, Canada
| | - D H Froula
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester New York 14623, USA
| | - J P Palastro
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester New York 14623, USA
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3
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Bowie JM, Calvo RY, Bansal V, Wessels LE, Butler WJ, Sise CB, Shaw JG, Sise MJ. Association of complicated gallstone disease in pregnancy and adverse birth outcomes. Am J Surg 2020; 220:745-750. [PMID: 32067705 DOI: 10.1016/j.amjsurg.2020.01.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 10/16/2019] [Revised: 01/20/2020] [Accepted: 01/20/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Complicated gallstone disease (CGD) is a common condition requiring intervention during pregnancy to avert adverse birth outcomes (ABO). METHODS Cohort study using the California OSHPD 2007-2014 database. Records of pregnant patients were analyzed for gallbladder calculus within four months of delivery. Biliary system interventions were evaluated as the primary exposure. RESULTS Of 7,597 patients, those with CGD had a greater likelihood of biliary system procedures than those with uncomplicated gallstone disease (36.6% vs. 2.5%, p < 0.001). Patients with CGD also had increased odds of ABO (OR 2.02, 95% CI, 1.48-2.76). Compared to patients without biliary system procedures, those with interventions for gallstones had an OR of 3.46 (95% CI, 2.48-4.82) for ABO. After adjustment, biliary system intervention for CGD had an even greater risk of ABO (OR 4.26, 95% CI, 2.86-6.35). CONCLUSIONS The risk of ABO is significantly increased in women with CGD and intervention for gallstones.
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Affiliation(s)
- Jason M Bowie
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - Richard Y Calvo
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - Vishal Bansal
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - Lyndsey E Wessels
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - William J Butler
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - C Beth Sise
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - Jennifer G Shaw
- Department of Obstetrics and Gynecology, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA
| | - Michael J Sise
- Trauma Service, Scripps Mercy Hospital, 4077 Fifth Avenue, San Diego, CA, 92103, USA.
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4
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Bates JW, Myatt JF, Shaw JG, Follett RK, Weaver JL, Lehmberg RH, Obenschain SP. Mitigation of cross-beam energy transfer in inertial-confinement-fusion plasmas with enhanced laser bandwidth. Phys Rev E 2018; 97:061202. [PMID: 30011586 DOI: 10.1103/physreve.97.061202] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 11/07/2022]
Abstract
Cross-beam energy transfer (CBET) is a significant energy-loss mechanism in directly driven inertial-confinement-fusion (ICF) targets. One strategy for mitigating CBET is to increase the bandwidth of the laser light, thereby disrupting the resonant three-wave interactions that underlie this nonlinear scattering process. Here, we report on numerical simulations performed with the wave-based code lpse that show a significant reduction in CBET for bandwidths of 2-5 THz (corresponding to a normalized bandwidth of 0.2%-0.6% at a laser wavelength of 351nm) under realistic plasma conditions. Such bandwidths are beyond those available with current high-energy lasers used for ICF, but could be achieved using stimulated rotation Raman scattering in diatomic gases like nitrogen.
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Affiliation(s)
- J W Bates
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - J F Myatt
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada T6G1H9
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R K Follett
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J L Weaver
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - R H Lehmberg
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - S P Obenschain
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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5
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Follett RK, Shaw JG, Myatt JF, Palastro JP, Short RW, Froula DH. Suppressing Two-Plasmon Decay with Laser Frequency Detuning. Phys Rev Lett 2018; 120:135005. [PMID: 29694175 DOI: 10.1103/physrevlett.120.135005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/06/2018] [Indexed: 06/08/2023]
Abstract
Three-dimensional laser-plasma interaction simulations show that laser frequency detuning by an amount achievable with current laser technology can be used to suppress the two-plasmon decay (TPD) instability and the corresponding hot-electron generation. For the plasma conditions and laser configuration in a direct-drive inertial confinement fusion implosion on the OMEGA laser, the simulations show that ∼0.7% laser frequency detuning is sufficient to eliminate TPD-driven hot-electron generation in current experiments. This allows for higher ablation pressures in future implosion designs by using higher laser intensities.
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Affiliation(s)
- R K Follett
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - J F Myatt
- Department of Electrical and Computer Engineering, University of Alberta, 9211 116th Street NW, Edmonton, Alberta T6G 1H9, Canada
| | - J P Palastro
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - R W Short
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - D H Froula
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
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6
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Shaw KA, Lerma K, Shaw JG, Scrivner KJ, Hugin M, Hopkins FW, Blumenthal PD. Preoperative effects of mifepristone for dilation and evacuation after 19 weeks of gestation: a randomised controlled trial. BJOG 2017; 124:1973-1981. [DOI: 10.1111/1471-0528.14900] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2017] [Indexed: 11/30/2022]
Affiliation(s)
- KA Shaw
- Division of Family Planning Services and Research; Department of Obstetrics & Gynecology; Stanford University School of Medicine; Stanford CA USA
| | - K Lerma
- Division of Family Planning Services and Research; Department of Obstetrics & Gynecology; Stanford University School of Medicine; Stanford CA USA
| | - JG Shaw
- Division of Primary Care and Population Health; Department of Medicine; Stanford University School of Medicine; Stanford CA USA
| | - KJ Scrivner
- Division of Family Planning Services and Research; Department of Obstetrics & Gynecology; Stanford University School of Medicine; Stanford CA USA
| | - M Hugin
- Department of Obstetrics & Gynecology; Santa Clara Valley Medical Center; San Jose CA USA
| | - FW Hopkins
- Division of Family Planning Services and Research; Department of Obstetrics & Gynecology; Stanford University School of Medicine; Stanford CA USA
- Department of Obstetrics & Gynecology; Santa Clara Valley Medical Center; San Jose CA USA
| | - PD Blumenthal
- Division of Family Planning Services and Research; Department of Obstetrics & Gynecology; Stanford University School of Medicine; Stanford CA USA
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7
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Guthrie KM, Rohan L, Rosen RK, Vargas SE, Shaw JG, Katz D, Kojic EM, Ham AS, Friend D, Buckheit KW, Buckheit RW. Vaginal film for prevention of HIV: using visual and tactile evaluations among potential users to inform product design. Pharm Dev Technol 2017; 23:311-314. [PMID: 28592183 DOI: 10.1080/10837450.2017.1339085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Topical prevention of HIV and other STIs is a global health priority. To provide options for users, developers have worked to design safe, effective and acceptable vaginal dissolving film formulations. We aimed to characterize user experiences of vaginal film size, texture and color, and their role in product-elicited sensory perceptions (i.e. perceptibility), acceptability and willingness to use. In the context of a user-centered product evaluation study, we elicited users' 'first impressions' of various vaginal film formulation designs via visual and tactile prototype inspection during a qualitative user evaluation interview. Twenty-four women evaluated prototypes. Participants considered size and texture to be important for easy insertion. Color was more important following dissolution than prior to insertion. When asked to combine and balance all properties to arrive at an ideal film, previously stated priorities for individual characteristics sometimes shifted, with the salience of some individual characteristics lessening when multiple characteristics were weighted in combination. While first impressions alone may not drive product uptake, users' willingness to initially try a product is likely impacted by such impressions. Developers should consider potential users' experiences and preferences in vaginal film design. This user-focused approach is useful for characterizing user sensory perceptions and experiences relevant to early design of prevention technologies.
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Affiliation(s)
- K M Guthrie
- a Centers for Behavioral and Preventive Medicine , The Miriam Hospital , Providence , RI , USA.,b Department of Psychiatry and Human Behavior , The Warren Alpert Medical School of Brown University , Providence , RI , USA.,c Department of Behavioral and Social Sciences , Brown University School of Public Health , Providence , RI , USA
| | - L Rohan
- d Magee-Womens Research Institute , Pittsburgh , PA , USA.,e University of Pittsburgh , Pittsburgh , PA , USA
| | - R K Rosen
- a Centers for Behavioral and Preventive Medicine , The Miriam Hospital , Providence , RI , USA.,c Department of Behavioral and Social Sciences , Brown University School of Public Health , Providence , RI , USA
| | - S E Vargas
- a Centers for Behavioral and Preventive Medicine , The Miriam Hospital , Providence , RI , USA.,b Department of Psychiatry and Human Behavior , The Warren Alpert Medical School of Brown University , Providence , RI , USA
| | - J G Shaw
- a Centers for Behavioral and Preventive Medicine , The Miriam Hospital , Providence , RI , USA
| | - D Katz
- f Biomedical Engineering and Obstetrics/Gynecology, Duke University , Durham , NC , USA
| | - E M Kojic
- g Division of Immunology , The Miriam Hospital , Providence , RI , USA
| | - A S Ham
- h ImQuest BioSciences, Inc , Frederick , MD , USA
| | | | - K W Buckheit
- h ImQuest BioSciences, Inc , Frederick , MD , USA
| | - R W Buckheit
- h ImQuest BioSciences, Inc , Frederick , MD , USA
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8
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Tauseef I, Harrison OB, Wooldridge KG, Feavers IM, Neal KR, Gray SJ, Kriz P, Turner DPJ, Ala'Aldeen DAA, Maiden MCJ, Bayliss CD, Shaw JG. Influence of the combination and phase variation status of the haemoglobin receptors HmbR and HpuAB on meningococcal virulence. Microbiology (Reading) 2011; 157:1446-1456. [PMID: 21310784 PMCID: PMC3352162 DOI: 10.1099/mic.0.046946-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Neisseria meningitidis can utilize haem, haemoglobin and haemoglobin–haptoglobin complexes as sources of iron via two TonB-dependent phase variable haemoglobin receptors, HmbR and HpuAB. HmbR is over-represented in disease isolates, suggesting a link between haemoglobin acquisition and meningococcal disease. This study compared the distribution of HpuAB and phase variation (PV) status of both receptors in disease and carriage isolates. Meningococcal disease (n = 214) and carriage (n = 305) isolates representative of multiple clonal complexes (CCs) were investigated for the distribution, polyG tract lengths and ON/OFF status of both haemoglobin receptors, and for the deletion mechanism for HpuAB. Strains with both receptors or only hmbR were present at similar frequencies among meningococcal disease isolates as compared with carriage isolates. However, >90 % of isolates from the three CCs CC5, CC8 and CC11 with the highest disease to carriage ratios contained both receptors. Strains with an hpuAB-only phenotype were under-represented among disease isolates, suggesting selection against this receptor during systemic disease, possibly due to the receptor having a high level of immunogenicity or being inefficient in acquisition of iron during systemic spread. Absence of hpuAB resulted from either complete deletion or replacement by an insertion element. In an examination of PV status, one or both receptors were found in an ON state in 91 % of disease and 71 % of carriage isolates. We suggest that expression of a haemoglobin receptor, either HmbR or HpuAB, is of major importance for systemic spread of meningococci, and that the presence of both receptors contributes to virulence in some strains.
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Affiliation(s)
- Isfahan Tauseef
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK
| | - Odile B Harrison
- The Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
| | - Karl G Wooldridge
- Molecular Bacteriology and Immunology Group, University of Nottingham, Nottingham, UK
| | - Ian M Feavers
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Hertfordshire EN6 3QG, UK
| | - Keith R Neal
- School of Community Health Sciences, University of Nottingham, Nottingham, UK
| | - Stephen J Gray
- Health Protection Agency, Meningococcal Reference Unit, Manchester Royal Infirmary, Manchester M13 9WL, UK
| | - Paula Kriz
- National Reference Laboratory for Meningococcal Infections, National Institute of Public Health, Prague, Czech Republic
| | - David P J Turner
- Molecular Bacteriology and Immunology Group, University of Nottingham, Nottingham, UK
| | - Dlawer A A Ala'Aldeen
- Molecular Bacteriology and Immunology Group, University of Nottingham, Nottingham, UK
| | - Martin C J Maiden
- The Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
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9
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Yang IA, Seeney SL, Wolter JM, Anders EM, McCormack JG, Tunnicliffe AM, Rabnott GC, Shaw JG, Dent AG, Kim ST, Zimmerman PV, Fong KM. Mannose-binding lectin gene polymorphism predicts hospital admissions for COPD infections. Genes Immun 2003; 4:269-74. [PMID: 12761563 DOI: 10.1038/sj.gene.6363961] [Citation(s) in RCA: 59] [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: 11/09/2022]
Abstract
Infection frequently causes exacerbations of chronic obstructive pulmonary disease (COPD). Mannose-binding lectin (MBL) is a pattern-recognition receptor that assists in clearing microorganisms. Polymorphisms in the MBL2 gene reduce serum MBL levels and are associated with risk of infection. We studied whether the MBL2 codon 54 B allele affected serum MBL levels, admissions for infective exacerbation in COPD and disease susceptibility. Polymorphism frequency was determined by PCR-RFLP in 200 COPD patients and 104 smokers with normal lung function. Serum MBL was measured as mannan-binding activity in a subgroup of 82 stable COPD patients. Frequency of COPD admissions for infective exacerbation was ascertained for a 2-year period. The MBL2 codon 54 B allele reduced serum MBL in COPD patients. In keeping, patients carrying the low MBL-producing B allele had increased risk of admission for infective exacerbation (OR 4.9, P(corrected)=0.011). No association of MBL2 genotype with susceptibility to COPD was detected. In COPD, serum MBL is regulated by polymorphism at codon 54 in its encoding gene. Low MBL-producing genotypes were associated with more frequent admissions to hospital with respiratory infection, suggesting that the MBL2 gene is disease-modifying in COPD. MBL2 genotype should be explored prospectively as a prognostic marker for infection risk in COPD.
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Affiliation(s)
- I A Yang
- Division of Thoracic Medicine, The Prince Charles Hospital, and Department of Medicine, University of Queensland, Brisbane, Australia.
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10
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Abstract
A survey of health library partnerships between the UK and northern European countries and African or eastern European countries was undertaken to complement a similar survey of 24 North American health libraries. Out of 11 partnerships described, six provided sufficient data to be included in a quantitative analysis. These results give some baseline data about such partnerships and their activities, reasons for success and problems encountered. Some libraries have little involvement other than sending duplicate books and journals; others are more deeply involved in all aspects of library activity including professional development. Good communications, both human and technological, are important for maintaining partnership momentum. Staff commitment on both sides and institutional support for the partnership are essential, especially when programmes have costs which must be met either by the institution or outside funders. The financial consequences of partnership may inhibit their initiation, but successful partnerships with demand driven programmes bring benefits to both sides.
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Affiliation(s)
- J G Shaw
- Partnerships in Health Information, The Old Rectory, Shoscombe, Bath, UK.
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11
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Rabaan AA, Gryllos I, Tomás JM, Shaw JG. Motility and the polar flagellum are required for Aeromonas caviae adherence to HEp-2 cells. Infect Immun 2001; 69:4257-67. [PMID: 11401962 PMCID: PMC98495 DOI: 10.1128/iai.69.7.4257-4267.2001] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [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: 09/27/2000] [Accepted: 03/19/2001] [Indexed: 11/20/2022] Open
Abstract
Aeromonas caviae is increasingly being recognized as a cause of gastroenteritis, especially among the young. The adherence of aeromonads to human epithelial cells in vitro has been correlated with enteropathogenicity, but the mechanism is far from well understood. Initial investigations demonstrated that adherence of A. caviae to HEp-2 cells was significantly reduced by either pretreating bacterial cells with an antipolar flagellin antibody or by pretreating HEp-2 cells with partially purified flagella. To precisely define the role of the polar flagellum in aeromonad adherence, we isolated the A. caviae polar flagellin locus and identified five polar flagellar genes, in the order flaA, flaB, flaG, flaH, and flaJ. Each gene was inactivated using a kanamycin resistance cartridge that ensures the transcription of downstream genes, and the resulting mutants were tested for motility, flagellin expression, and adherence to HEp-2 cells. N-terminal amino acid sequencing, mutant analysis, and Western blotting demonstrated that A. caviae has a complex flagellum filament composed of two flagellin subunits encoded by flaA and flaB. The predicted molecular mass of both flagellins was approximately 31,700 Da; however, their molecular mass estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was approximately 35,500 Da. This aberrant migration was thought to be due to their glycosylation, since the proteins were reactive in glycosyl group detection assays. Single mutations in either flaA or flaB did not result in loss of flagella but did result in decreased motility and adherence by approximately 50%. Mutation of flaH, flaJ, or both flagellin genes resulted in the complete loss of motility, flagellin expression, and adherence. However, mutation of flaG did not affect motility but did significantly reduce the level of adherence. Centrifugation of the flagellate mutants (flaA, flaB, and flaG) onto the cell monolayers did not increase adherence, whereas centrifugation of the aflagellate mutants (flaH, flaJ, and flaA flaB) increased adherence slightly. We conclude that maximum adherence of A. caviae to human epithelial cells in vitro requires motility and optimal flagellar function.
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Affiliation(s)
- A A Rabaan
- Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
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12
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Abstract
The adherence mechanism of Aeromonas caviae Sch3N to HEp-2 cells was initially investigated through four mini-Tn5 mutants that showed a 10-fold decrease in adherence. These mutants lost motility, flagella, and their lipopolysaccharide (LPS) O antigen (O-Ag). Three genes, flmB-neuA-flmD, were found to be interrupted by the transposon insertions; additionally, two other genes, one lying upstream (flmA) and one downstream (neuB), were found to be clustered in the same operon. While the flmA and flmB genes were present in all mesophilic Aeromonas spp. (A. hydrophila, A. caviae, A. veronii bv. veronii, and A. veronii bv. sobria) tested, this was not the case for the neuA-flmD-neuB genes. Construction and characterization of flmB insertion mutants in five other mesophilic Aeromonas strains revealed the loss of motility, flagella, and adherence but did not alter the LPS composition of these strains. Taking the above findings into consideration, we conclude (i) that flagella and possibly the LPS O-Ag are involved in the adherence of the mesophilic Aeromonas to human epithelial cells; (ii) flmA and flmB are genes widely distributed in the mesophilic Aeromonas and are involved in flagella assembly, and thus adherence; and (iii) in A. caviae Sch3N the flmA and flmB genes are found in a putative operon together with neuA, flmD, and neuB and are involved in LPS O-Ag biosynthesis and probably have a role in flagellum assembly.
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Affiliation(s)
- I Gryllos
- Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
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13
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Affiliation(s)
- G Shalom
- University of Sheffield Medical School, UK
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14
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Moreno M, Brandwagt BF, Shaw JG, Rodríguez-Cerezo E. Infectious virus in transgenic plants inoculated with a nonviable, P1-proteinase defective mutant of a potyvirus. Virology 1999; 257:322-9. [PMID: 10329543 DOI: 10.1006/viro.1999.9692] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A mutant (P1-616) of the tobacco vein mottling potyvirus that contains a four-codon insertion in the P1 protein coding region of the viral RNA is unable to infect the normal host plant of the virus. Processing of the P1/HC-Pro cleavage site does not occur during in vitro translation of the mutant viral RNA. When plants transformed with the P1/HC-Pro/P3 coding region of tobacco vein mottling potyvirus RNA were inoculated with P1-616, some of them became infected, although there was a delay in the production of disease symptoms. Virus isolated from these plants was able to infect nontransgenic plants. Two variants of the recovered, infectious virus contained single-nucleotide alterations in the four-codon insertion in the P1-616 genome. In vitro translation of the variant genomic RNAs resulted in partial processing of the P1/HC-Pro cleavage site, although serological analysis of infected tissue showed complete processing in vivo. These results indicate that limited complementation of P1-616 occurs in the transgenic plants and that eventually there arises one or more variants of the mutant sequence that can effect P1/HC-Pro processing and therefore be replicated.
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Affiliation(s)
- M Moreno
- Centro Nacional de Biotecnología (CSIC), Madrid, Cantoblanco, 28049, Spain
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15
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Abstract
In order to establish infections, viruses must be delivered to the cells of potential hosts and must then engage in activities that enable their genomes to be expressed and replicated. With most viruses, the events that precede the onset of production of progeny virus particles are referred to as the early events and, in the case of positive-strand RNA viruses, they include the initial interaction with and entry of host cells and the release (uncoating) of the genome from the virus particles. Though the early events remain one of the more poorly understood areas of plant virology, the virus with which most of the relevant research has been performed is tobacco mosaic virus (TMV). In spite of this effort, there remains much uncertainty about the form or constituent of the virus that actually enters the initially invaded cell in a plant and about the mechanism(s) that trigger the subsequent uncoating (virion disassembly) reactions. A variety of approaches have been used in attempts to determine the fate of TMV particles that are involved in the establishment of an infection and these are briefly described in this review. In some recent work, it has been proposed that the uncoating process involves the bidirectional release of coat protein subunits from the viral RNA and that these activities may be mediated by cotranslational and coreplicational disassembly mechanisms.
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Affiliation(s)
- J G Shaw
- Department of Plant Pathology, University of Kentucky, Lexington 40546, USA
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16
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Abstract
A search for the first region in the genomic RNA of a potyvirus to be encapsidated during the assembly of virus particles in vivo has been undertaken. Protoplasts were collected at various times after inoculation and fragments of viral RNA that were protected from nuclease degradation were isolated from extracts and identified by RT-PCR procedures. Nuclease-resistant fragments of viral RNA were not detected in protoplasts that had been infected for 30 min. However, such fragments were present in protoplasts collected 40 min after inoculation and these contained a region at or near the 5' terminus of the viral RNA. Protoplasts that had been infected for 45 min or longer contained full-length viral RNA in a nuclease-resistant form. These results suggest that assembly of virus particles begins with the interaction of coat protein subunits with the 5' terminal region of progeny viral RNA molecules.
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Affiliation(s)
- X Wu
- Department of Plant Pathology, University of Kentucky, Lexington 40546, USA
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17
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Hinrichs J, Berger S, Shaw JG. A hypersensitive response-like mechanism is involved in resistance of potato plants bearing the Ry(sto) gene to the potyviruses potato virus Y and tobacco etch virus. J Gen Virol 1998; 79 ( Pt 1):167-76. [PMID: 9460939 DOI: 10.1099/0022-1317-79-1-167] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [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: 02/06/2023] Open
Abstract
Potato plants carrying the Ry(sto) gene from Solanum stoloniferum are extremely resistant to a number of potyviruses, but it is not known at what stage of infection the resistance is expressed. The resistance may be due to Ry(sto) or to a closely linked gene. In this investigation, we used potato virus Y (PVY) and a tobacco etch virus construct that encodes beta-glucuronidase (TEV-GUS) to monitor virus infections of potato plants. Systemic spread of either virus in resistant potato plants was not detectable by serology, RT-PCR, GUS assay or bioassay although each replicated in the initially infected cells of leaves from resistant potato cultivars and was transported into neighbouring cells. However, 3 days post-inoculation (p.i.) a necrotic reaction set in that stopped movement and accumulation of both viruses by 7 days p.i. The resistance reaction (probably a hypersensitive reaction) became visible as necrotic streaks on veins on the lower leaflet surfaces of some potato cultivars carrying the Ry(sto) gene and may be elicited by a common potyviral gene product.
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Affiliation(s)
- J Hinrichs
- University of Kentucky, College of Agriculture, Plant Pathology, Lexington 40546-0091, USA.
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18
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Abstract
Tobacco mosaic virus (TMV) particles have been shown to undergo bidirectional disassembly when they are introduced into host cells. Approximately three-quarters of the genomic RNA (i.e., the 126-kDa and 183-kDa protein ORFs) is first uncoated in the 5'-to-3' direction and the process is then completed by removal of coat protein molecules in the 3'-to-5' direction. An effort was made to determine whether the 126-kDa protein or the 183-kDa protein, both of which are involved in replication of the viral RNA, is required for the second part of the disassembly reaction. It was shown that progeny negative-strand viral RNA begins to be produced in inoculated cells at about the same time that 3'-to-5' disassembly is initiated thus suggesting that the two processes may be coupled. Particles containing mutant forms of the viral RNA in which large sections of the 126-kDa and 183-kDa protein ORFs were missing were not disassembled in the 3'-to-5' direction when they were introduced into cells. However, they were disassembled when the inoculum contained purified TMV RNA from which, presumably, the two functional proteins could be translated Particles containing mutants of the RNA from which a few codons had been deleted in or near conserved regions in the 126-kDa protein ORF also did not undergo 3'-to-5' disassembly unless mixed with wild type viral RNA prior to inoculation. These results suggest that the 126-kDa and/or 183-kDa protein plays a role in the completion of disassembly of TMV particles at the onset of the infection process.
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Affiliation(s)
- X Wu
- Department of Plant Pathology, University of Kentucky, Lexington 40546-0091, USA
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19
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Rodríguez-Cerezo E, Findlay K, Shaw JG, Lomonossoff GP, Qiu SG, Linstead P, Shanks M, Risco C. The coat and cylindrical inclusion proteins of a potyvirus are associated with connections between plant cells. Virology 1997; 236:296-306. [PMID: 9325237 DOI: 10.1006/viro.1997.8736] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [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: 02/05/2023]
Abstract
The subcellular locations of two potyviral proteins, the coat (CP) and nonstructural cylindrical inclusion (CI) proteins of tobacco vein mottling virus (TVMV), during early stages in the development of systemic infections in plants, have been investigated. Ultrathin sections of newly emerged leaves in infected plants were treated with antibodies specific to these proteins and then with gold-labeled secondary antibodies and examined by electron microscopy. CI was detected near plasmodesmatal connections between mesophyll cells prior to the appearance of CP or any virus-induced features or effects. Further accumulation of CI was evident in the form of conical structures, many of which appeared to penetrate the cell wall and to be connected to cones in neighboring cells. Prior to its appearance in other parts of the cells, the viral CP was detected, often in linear arrays, near the vertices or inside the cones and in plasmodesmata. In situ hybridization analysis of similar tissue sections with a TVMV RNA-specific oligoribonucleotide probe revealed the presence of the viral RNA in plasmodesmata. These results lend support to the notion that the formation of specific structures by potyviral CI proteins is required for and plays a direct role in the intercellular passage of viral genetic material, in the form of virus particles or complexes containing viral CP and RNA, in infected plants.
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20
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Abstract
DNA-based immunization is a promising new technique for generating antibodies in laboratory animals for diagnostic purposes in biological science. The main advantages are the elimination of time and labor and the technically demanding steps of antigen purification. The DNA sequence of the protein of interest, cloned in a suitable in vivo expression vector that is administered intramuscularly or intradermally, is sufficient to induce an immune response in animals. We report the induction of antibodies to tobacco mosaic virus (TMV) coat protein (CP) as a highly immunogenic structural protein and potato virus Y (PVY) P1 protein (P1) as a nonstructural protein. The appropriate nucleotide sequences were introduced in a mammalian expression vector (pSG5) and injected intramuscularly into New Zealand White rabbits (Oryctolagus cuniculus). By 10 days post-injection (dpi) a specific immune response was detected against TMV-CP, while it took about 5 weeks for a response to PVY P1. In both cases the antibody titers were significantly above the corresponding pre-immune serum, however, they were considerably below the titer of the matching conventionally produced antiserum. To our knowledge, this is the first report of DNA-based immunization in order to generate antibodies to plant viral proteins, but further improvements are necessary to increase antibody titers before this promising new technique can be introduced broadly in plant science for diagnostic purposes.
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Affiliation(s)
- J Hinrichs
- University of Kentucky, College of Agriculture, Lexington 40546-0091, USA
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21
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Shaw JG. Journals and the Internet. Copyright must be reconsidered. BMJ 1997; 314:1352. [PMID: 9158494 PMCID: PMC2126580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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22
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Abstract
Adherence of Aeromonas caviae to HEp-2 and Caco-2 cell monolayers was investigated with 24 clinical isolates. Growth phase, temperature, multiplicity of infection and length of incubation affected adherence. Treatment of the bacteria with trypsin, sodium metaperiodate, mechanical shearing and the addition of cytochalasin B and cycloheximide to the monolayer significantly reduced the adherence capabilities of the strains investigated. The use of chloramphenicol to inhibit protein synthesis reduced the adhesive capabilities of bacteria grown in liquid medium and those subjected to mechanical shearing. Light microscopy, scanning and transmission electron microscopy were employed in the investigation of bacteria-bacteria and bacteria-monolayer interactions and indicated similarities with the aggregative adherence patterns of the Enterobacteriaceae. The presence of extracellular bacterial appendages and their correlation with increased adhesive capacity may indicate a role in the process of adherence.
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Affiliation(s)
- J P Thornley
- Department of Medical Microbiology, University of Sheffield Medical School
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23
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Abstract
Mutants of tobacco vein mottling virus (TVMV) were constructed in which the tyrosine residue (Tyr1860) that links the VPg to the viral RNA was changed to phenylalanine or serine or was inverted in position with the adjacent glycine residue. In another mutant, the tyrosine residue nearest to Tyr1860 (Tyr1867) was changed to a phenylalanine residue. The resulting mutants were tested for their ability to infect Nicotiana tabacum plants or protoplasts. The Tyr1860 mutants did not accumulate to detectable levels in infected plants when tested by ELISA and Northern blot analysis. Moreover, the Tyr1860-associated mutants were not infectious in protoplasts, indicating that mutations involving the linking amino acid of the TVMV VPg abolished viral replićation. In contrast to the Tyr1860 mutants, transcripts from the mutation of Tyr1867 to a phenylalanine residue infected both protoplasts and plants. Analysis of progeny RNA from plants inoculated with the Tyr1867 mutant indicated that a reversion to wild type had occurred in systemically infected leaves.
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Affiliation(s)
- J F Murphy
- Department of Plant Pathology, Auburn University, Alabama 36849, USA
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24
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Abstract
The two-hybrid system was used to test for pairwise interactions between the tobacco vein mottling virus (TVMV)-encoded RNA-dependent RNA polymerase (or NIb protein) and two other TVMV-encoded proteins: the NIa protein, which consists of genome-linked protein (VPg) and proteinase domains, and the viral coat protein (CP). Using this approach, we find that the NIb protein interacts with both the NIa protein and the CP in yeast cells. Moreover, we find that a mutation in the conserved GDD domain of the NIb protein diminishes the NIb-CP interaction but not the NIb-NIa interaction. Likewise, mutations in the vicinity of the NIa protein to which the genomic RNA is covalently attached eliminate the NIb-NIa interaction. We conclude that the NIb protein interacts with the VPg domain of the NIa protein and that this interaction requires a functional RNA attachment site. This interaction may be important for the initiation of viral RNA synthesis in infected cells. We also conclude that the CP interacts with the NIb in a manner that is sensitive in changes in the highly conserved GDD motif. The role of this interaction in the functioning of the NIb protein or the CP is unclear, but may involve regulation of viral RNA synthesis in infected cells.
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Affiliation(s)
- Y Hong
- Department of Agronomy, University of Kentucky, Lexington 40546-0091, USA
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25
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Crenshaw CA, Shaw JG. Commentary on JFK autopsy articles. JAMA 1995; 273:1632; discussion 1633. [PMID: 7745780 DOI: 10.1001/jama.273.20.1632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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26
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Abstract
We have used a cDNA clone of the potyvirus, tobacco vein mottling virus, to construct 19 mutants bearing 12-nt insertions in the viral genome. These mutants display a variety of phenotypes in inoculated tobacco plants or protoplasts. All mutants with insertions in P3, CI, 6K, NIa, or NIb failed to produce detectable amounts of progeny viral RNA in protoplasts or plants which suggests that they all may be directly involved in replication. Mutants (one in P1 and one in HCpro) presumably affected in polyprotein processing also did not replicate in plants or protoplasts. Seven mutants, with insertions in the 5' noncoding region, P1, HCpro, or CP regions of the genome, were able to infect protoplasts. Three of the 7 mutants (1 in the 5' noncoding region and 2 in HCpro) were able to infect protoplasts but not plants. The remaining 4 mutants replicated in protoplasts and were able to cause systemic infection in plants. The mutation in the CP had no effect on virus accumulation or symptom development in inoculated plants, whereas the other 3 (1 in P1 and 2 in HCpro) induced cyclical patterns of symptom expression. These symptoms ranged from very mild to wild-type-like as new leaves emerged and, as the plants continued to grow, this pattern was repeated. These results support the assignment of roles in replication to five coding regions in the genome and demonstrate that sequence alterations in many parts of other regions of the viral genome may have pronounced effects on replication and the expression of disease symptoms.
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Affiliation(s)
- P G Klein
- Department of Horticulture and Landscape Architecture, University of Kentucky, Lexington 40546
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27
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28
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Abstract
The disassembly of tobacco mosaic virus particles during the establishment of infections in tobacco protoplasts was investigated by reverse transcription and PCR analysis of the parts of the viral RNA that remained encapsidated at various times after inoculation. Within the first 3 min, uncoating had proceeded from the 5' terminus of the viral RNA to a position at least 4635 nucleotides from the 5' terminus. Removal of coat protein subunits from the part of the virus particle near the origin of assembly sequence of the RNA occurred more slowly. The results also suggested that progeny virus particles began to be produced 35-40 min after inoculation.
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Affiliation(s)
- X Wu
- Department of Plant Pathology, University of Kentucky, Lexington 40546
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29
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Boyle RL, Shaw JG, Stewart D. A winning game plan for QI. Med Group Manage J 1994; 41:24-6, 28, 30-3. [PMID: 10131357] [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: 02/11/2023]
Abstract
Authors Robert L. Boyle, Jr., M.P.H., FACMPE, James G. Shaw, M.B.A., and Diane Stewart describe how to put a quality improvement program into practice by identifying key internal processes, selecting an improvement program, identifying what to improve and developing a review method. They also present results from the first year of their quality improvement process.
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Affiliation(s)
- R L Boyle
- Palo Alto Medical Foundation, CA 94301
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30
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Rodríguez-Cerezo E, Ammar ED, Pirone TP, Shaw JG. Association of the non-structural P3 viral protein with cylindrical inclusions in potyvirus-infected cells. J Gen Virol 1993; 74 ( Pt 9):1945-9. [PMID: 8397284 DOI: 10.1099/0022-1317-74-9-1945] [Citation(s) in RCA: 46] [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: 01/30/2023] Open
Abstract
Antibodies raised against the 42K non-structural P3 protein encoded by the RNA genome of a potyvirus (tobacco vein mottling virus, TVMV) have been used with immunogold labelling procedures to determine the subcellular location of P3 in infected Nicotiana tabacum cells. P3-specific gold label was found almost exclusively associated with the cylindrical inclusions typically formed in the cytoplasm of potyvirus-infected cells by another non-structural viral protein, the cylindrical inclusion protein. The P3 antibodies reacted with inclusions in both the transverse (pinwheel-like) and longitudinal (bundle-like) orientations of these structures. Immunocytological examination of TVMV-infected protoplasts showed the association of P3 with cylindrical inclusions during the early stages of formation of these structures and suggests that the P3 may be involved in the replication of potyviral RNA.
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31
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Wilson JB, Brennan SO, Allen J, Shaw JG, Gu LH, Huisman TH. The M gamma chain of human fetal hemoglobin is an A gamma chain with an in vitro modification of gamma 141 leucine to hydroxyleucine. J Chromatogr 1993; 617:37-42. [PMID: 7690768 DOI: 10.1016/0378-4347(93)80418-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have reanalyzed the structure of the gamma T-15 peptide from the minor M gamma chain of human hemoglobin (Hb) F. Amino acid analysis confirmed that the Leu 141 residue was missing from position 9 of this peptide, and liquid secondary ion mass spectrometry indicated that it was replaced, not by methionine (residue mass 131) as previously believed, but by an amino acid of mass 129. By analogy with the recently reported oxidation of the corresponding leucine at position gamma 141 of the unstable Hb Atlanta, it appears that the M gamma chain also results from the oxidation of gamma 141 to hydroxyleucine (residue mass 129). The finding that the proportion of the M gamma chain increased when red cell lysates were prepared with carbon tetrachloride prompted us to reinvestigate the oxidation mechanism involved in the formation of beta 141 hydroxyleucine in Hb Atlanta. Oxidation of the beta 141 residue could be detected when carbon tetrachloride was used in the lysis protocol, while conversion of oxyhemoglobin to carbon monoxyhemoglobin prior to carbon tetrachloride treatment prevented oxidation. It therefore appears that the hydroxylation of Leu 141 is not an in vivo process in the circulating red cell. Perhaps leucine at position 141 of the beta, gamma, and delta chains (and at position 136 of the alpha chain), which forms a contact with heme and is located directly across the heme plate from the E helix, is oxidized to hydroxyleucine at a very low rate forming minute amounts of modified chains; this process is accelerated by treatment with agents such as carbon tetrachloride and prolonged exposure to air.
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Affiliation(s)
- J B Wilson
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, 30912-2100
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32
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Abstract
Transgenic tobacco plants that express the genome-linked protein/proteinase-coding region of the potyvirus tobacco vein mottling virus (TVMV) were produced and tested for their reaction to inoculation with TVMV and two other potyviruses. These plants did not develop disease symptoms after being inoculated with large doses of TVMV but were as susceptible to infection by the other potyviruses as were control plants. Lines of tobacco that express the coat protein- or the nonstructural cylindrical inclusion protein-coding regions were also produced. The coat protein transgenic plants were protected against all three potyviruses, and the cylindrical inclusion transgenic plants were susceptible to all three potyviruses. These results indicate that some, but not all, TVMV genes can be used to confer protection against potyviruses in plants. The results also suggest that combinations of viral genes in transgenic plants might improve protection against potyviruses.
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Affiliation(s)
- I B Maiti
- Department of Agronomy, University of Kentucky, Lexington 40546-0091
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33
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Hamblin MJ, Shaw JG, Kelly DJ. Sequence analysis and interposon mutagenesis of a sensor-kinase (DctS) and response-regulator (DctR) controlling synthesis of the high-affinity C4-dicarboxylate transport system in Rhodobacter capsulatus. Mol Gen Genet 1993; 237:215-24. [PMID: 8455557 DOI: 10.1007/bf00282803] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A two-component sensor-regulator system has been identified in the purple photosynthetic bacterium Rhodobacter capsulatus, which controls the expression of high-affinity C4-dicarboxylate transport activity in these cells. Nucleotide sequencing has revealed the existence of two genes, dctS and dctR, which together form an operon linked to, but divergently transcribed from, the previously identified dctP gene, which encodes the periplasmic binding protein of the transport system. The DctS protein is predicted to be a membrane-bound sensor-kinase with two potential membrane-spanning sequences in the N-terminal region. DctR was found to have sequence similarity throughout its entire length with proteins in the FixJ subfamily of response-regulators, especially to FixJ itself (42% identical residues). Insertional inactivation of the dctS and dctR genes resulted in the inability of the resulting mutants to grow on or transport malate, succinate or fumarate under aerobic conditions in the dark, and such mutants did not express the DctP protein. The mutants were complemented in trans by plasmids containing intact copies of the dctS and dctR genes.
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Affiliation(s)
- M J Hamblin
- Krebs and Robert Hill Institutes, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K
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34
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Brennan SO, Shaw JG, George PM, Huisman TH. Posttranslational modification of beta 141 Leu associated with the beta 75(E19)Leu-->Pro mutation in Hb Atlanta. Hemoglobin 1993; 17:1-7. [PMID: 8454467 DOI: 10.3109/03630269308998880] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The recent report of the oxidation of beta 141 Leu in a New Zealand family with Hb Atlanta [ beta 75(E19)Leu-->Pro] prompted us to reinvestigate the original Hb Atlanta case from Georgia. Tryptic peptide maps showed that the modified beta CoT-14 peptide was present together with beta AT-14 in isopropanol precipitates of Hb Atlanta. Amino acid analysis confirmed that beta CoT-14 lacked leucine and mass spectrometry indicated that it had an increased mass of 16 Daltons. These findings support the proposition that the beta 75 Leu-->Pro substitution in the E helix is the direct cause of the beta 141 Leu oxidation.
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Affiliation(s)
- S O Brennan
- Pathology Department, Christchurch Hospital, New Zealand
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35
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Walmsley AR, Shaw JG, Kelly DJ. Perturbation of the equilibrium between open and closed conformations of the periplasmic C4-dicarboxylate binding protein from Rhodobacter capsulatus. Biochemistry 1992; 31:11175-81. [PMID: 1445856 DOI: 10.1021/bi00160a031] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A kinetic and thermodynamic analysis has been carried out on the conformational transitions of the periplasmic C4-dicarboxylate binding protein (DctP) from the photosynthetic bacterium Rhodobacter capsulatus. This protein is distinct from other periplasmic binding proteins characterized to date in that the transition between the putative closed-unliganded (BP1) and open-unliganded (BP2) conformations is slow compared to the rate of ligand binding [Walmsley, A. R., Shaw, J. G., & Kelly, D. J. (1992) J. Biol. Chem. 276, 8064-8072]. Using stopped-flow fluorescence techniques, we have probed the conformational dynamics of the closed to open transition of DctP in the absence and presence of ligand. Both the forward rate constant for the BP1 to BP2 interconversion (k1) and the fumarate dissociation rate constant (k-3) were found to increase in a biphasic manner between pH 5 and pH 11. The data were fitted to a two-pKa function which gave pKa values of 10.3 and 5.4 for the BP1 to BP2 interconversion and 8.9 and 4.5 for the closed-liganded (BP3L) to open-liganded (BP2L) transition. An increase in ionic strength at constant pH resulted in a hyperbolic increase in both k1 and k-3 to maximal rates that were similar in each case to the values obtained in pH variation experiments. Measurement of the temperature dependencies of k1 and k-3 also gave similar activation energies. Gibbs free energy, enthalpy, and entropy changes were determined for the open to closed transitions of DctP in both the presence and absence of ligand.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A R Walmsley
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, United Kingdom
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36
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Walmsley AR, Shaw JG, Kelly DJ. The mechanism of ligand binding to the periplasmic C4-dicarboxylate binding protein (DctP) from Rhodobacter capsulatus. J Biol Chem 1992; 267:8064-72. [PMID: 1569065] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The kinetics of ligand binding to the periplasmic C4-dicarboxylate binding protein (DctP) from Rhodobacter capsulatus were investigated by exploiting the changes in the intrinsic fluorescence of the protein upon binding ligands. Steady state measurements have shown that L-malate, succinate, and fumarate are all bound with sub-micromolar Kd values, whereas D-malate is bound 2 orders of magnitude more weakly. Stopped-flow studies have revealed that the binding process involves at least three steps. In the absence of ligand, the protein is in equilibrium between an essentially nonbinding form, BP1, and the binding form, BP2. Ligands bind to the BP2 form, shifting the equilibrium toward the BP2-L conformation, and also inducing a further isomerization of the protein, to the BP3-L form. The kinetic properties of the four different conformational states of the DctP protein identified in this study would be consistent with their identification as the closed-conformation, the open-conformation, an open-liganded conformation, and a closed-liganded conformation. The latter three states have been identified by x-ray crystallographic studies of binding proteins, but no kinetic or structural data have been presented previously to support the possibility of a closed but unliganded conformation.
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Affiliation(s)
- A R Walmsley
- Krebs and Robert Hill Institutes, Department of Molecular Biology and Biotechnology, University of Sheffield, United Kingdom
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37
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Shaw JG, Hamblin MJ, Kelly DJ. Purification, characterization and nucleotide sequence of the periplasmic C4-dicarboxylate-binding protein (DctP) from Rhodobacter capsulatus. Mol Microbiol 1991; 5:3055-62. [PMID: 1809844 DOI: 10.1111/j.1365-2958.1991.tb01865.x] [Citation(s) in RCA: 50] [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: 12/28/2022]
Abstract
A periplasmic binding protein essential for high-affinity transport of the C4-dicarboxylates malate, succinate and fumarate across the cytoplasmic membrane of the purple photosynthetic bacterium Rhodobacter capsulatus has been purified to homogeneity and some of its ligand-binding properties characterized. The protein was not produced in a Tn5 insertion mutant unable to transport C4-dicarboxylates under aerobic conditions in the dark. Wild-type DNA corresponding to the location of the transposon insertion site was subcloned and a 1.5 kb section sequenced. A complete open reading frame of 999 bp was identified that encoded a 333-residue protein (DctP) with a molecular weight of 36,128 with a 26-residue amino-terminal signal peptide. The identify of this protein with the purified dicarboxylate-binding protein and the position of the predicted signal peptide cleavage site was confirmed by N-terminal sequencing. No significant homology with other proteins was detected in database searches. A GC-rich region of dyad symmetry was located 7 bp downstream of the dctP translational stop codon. This structure may be of significance in regulating the relative abundance of DctP and other dct gene products which comprise the high-affinity dicarboxylate transport system in this bacterium.
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Affiliation(s)
- J G Shaw
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, U.K
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38
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Abstract
The existence of two viral RNA-encoded proteins in cells infected with tobacco vein mottling potyvirus (TVMV) has been demonstrated. One of the proteins (named 34K) maps at the N-terminus of the TVMV polyprotein and the other (42K) between the helper component and cylindrical inclusion proteins; both had previously been predicted in the consensus potyviral genetic map. The 34K and 42K coding regions of TVMV were cloned separately in a bacterial expression vector and the proteins were isolated from transformed Escherichia coli. These were used to raise polyclonal antibodies which reacted specifically with proteins of the expected size in immunoblots of extracts of TVMV-infected tobacco leaves and protoplasts. In addition to 42K, the anti-42K serum detected similar amounts of a second protein of apparent size 37 kDa that was absent in 42K-expressing bacteria. Both 34K and 42K were present predominantly in membrane-enriched fractions of extracts of TVMV-infected tobacco leaves. Computer analysis of the deduced amino acid sequence of 42K suggests that this viral protein may be an integral transmembrane protein.
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39
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Rodríguez-Cerezo E, Klein PG, Shaw JG. A determinant of disease symptom severity is located in the 3'-terminal noncoding region of the RNA of a plant virus. Proc Natl Acad Sci U S A 1991; 88:9863-7. [PMID: 1946413 PMCID: PMC52821 DOI: 10.1073/pnas.88.21.9863] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Inoculation of Nicotiana tabacum plants with RNA transcribed in vitro from a variant (pXBS8) of a cloned full-length DNA copy of tobacco vein mottling virus (TVMV) RNA resulted in attenuation of the vein mottling and blotching symptoms typically produced by transcripts of cloned wild-type cDNA (pXBS7). Similar amounts of virus were detected by ELISA (using anti-TVMV coat protein serum) in systemically infected leaves of plants inoculated with pXBS7 or pXBS8 transcripts. pXBS8 was shown to contain a 58-nucleotide segment in the sequence corresponding to the 3'-terminal untranslated region of TVMV RNA that was not present in pXBS7. This segment resulted in the appearance in pXBS8 transcripts of four adjacent direct repeats of a 14-nucleotide sequence, AUAAUUAUAUAUAU, that is present in the 3'-untranslated region of TVMV RNA, with two additional nucleotides (AU) between the first and second repeats. Insertion of restriction fragments containing the segment into pXBS7 and inoculation of plants with transcripts of the chimeric construct (pXBS78) resulted in the attenuated-symptom phenotype and was not accompanied by a reduced accumulation of virus in the plant as determined by ELISA and Northern blot analysis. When the extra nucleotides were removed from the variant clone, symptoms induced by transcripts of the cDNA (pXBS87) resembled those induced by wild-type transcripts. The results indicate that a noncoding region of the genome can have a direct effect on the induction of disease symptoms by an RNA virus.
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Abstract
RNA prepared from the potyvirus tobacco vein mottling virus contained aggregates of the 9.5 kb genomic RNA with electrophoretic mobilities corresponding to 20 and 41 kb species. Similar aggregates were present in preparations of the RNAs of two other potyviruses. Aggregation occurred during or after purification of the RNA by sucrose gradient centrifugation and alcohol precipitation and was dependent upon the presence of a protein apparently bound covalently to a region at or near the 5' terminus of the viral RNA. This protein is probably the VPg. The RNAs of tobacco mosaic virus and cowpea mosaic virus did not form aggregates when isolated from purified virus by similar procedures.
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Affiliation(s)
- C S Luciano
- Department of Plant Pathology, University of Kentucky, Lexington 40546
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41
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Murphy JF, Rychlik W, Rhoads RE, Hunt AG, Shaw JG. A tyrosine residue in the small nuclear inclusion protein of tobacco vein mottling virus links the VPg to the viral RNA. J Virol 1991; 65:511-3. [PMID: 1702164 PMCID: PMC240548 DOI: 10.1128/jvi.65.1.511-513.1991] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [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: 12/28/2022] Open
Abstract
The identity of the amino acid residue that links the VPg of the potyvirus tobacco vein mottling virus (TVMV) to the viral RNA was determined. 32P-labeled TVMV RNA was digested with RNase A and micrococcal nuclease. The resulting 32P-labeled VPg was isolated and partially hydrolyzed with 6 N HCl at 110 degrees C for 2 h. Analysis by thin-layer electrophoresis revealed the presence of [32P]phosphotyrosine but not [32P]phosphoserine or [32P]phosphothreonine. Another preparation of TVMV RNA was treated with endoproteinase Lys-C, and the resulting peptide-RNA was purified by sodium dodecyl sulfate-sucrose gradient centrifugation. The sequence of the N-terminal 15 amino acid residues of the peptide, when compared with the RNA-derived amino acid sequence of the TVMV polyprotein, demonstrated that the peptide occurs in the small nuclear inclusion protein. These data suggest that Tyr-1860 of the polyprotein is the amino acid residue that links the TVMV VPg to the viral RNA.
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Affiliation(s)
- J F Murphy
- Department of Plant Pathology, University of Kentucky, Lexington 40546-0091
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Wu XJ, Beachy RN, Wilson TM, Shaw JG. Inhibition of uncoating of tobacco mosaic virus particles in protoplasts from transgenic tobacco plants that express the viral coat protein gene. Virology 1990; 179:893-5. [PMID: 2238480 DOI: 10.1016/0042-6822(90)90163-l] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The uncoating of tobacco mosaic virus (TMV) particles in protoplasts isolated from leaves of transgenic tobacco plants that express the TMV coat protein gene was investigated. Extracts of these protoplasts collected up to 1 hr after inoculation with TMV contained fewer of the complexes ("striposomes") thought to be involved in cotranslational disassembly of virus particles than did extracts of protoplasts that do not express the viral coat protein gene. These results are consistent with the hypothesis that TMV coat protein-mediated resistance is at least in part the result of inhibition of the uncoating of the virus particles in the inoculum.
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Affiliation(s)
- X J Wu
- Department of Plant Pathology, University of Kentucky, Lexington 40546
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Hamblin MJ, Shaw JG, Curson JP, Kelly DJ. Mutagenesis, cloning and complementation analysis of C4-dicarboxylate transport genes from Rhodobacter capsulatus. Mol Microbiol 1990; 4:1567-74. [PMID: 1962840] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Transposon mutagenesis was used to isolate insertion mutants of the photosynthetic bacterium Rhodobacter capsulatus which were unable to grow under aerobic conditions in the dark on malate, succinate or fumarate as sole carbon sources. Of five mutants isolated, all were deficient in C4-dicarboxylate transport. However, these mutants were still capable of photoheterotrophic growth, although at a slower rate than the wild type, on malate and succinate (but not fumarate). The mutated locus (designated dct) was complemented in trans using a cosmid gene bank. Subcloning and complementation analysis indicated that at least three closely linked genes essential for aerobic dicarboxylate transport were contained within an 8.3 kb region of the Rhodobacter capsulatus chromosome.
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Affiliation(s)
- M J Hamblin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, UK
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Abstract
Preparations of tobacco etch virus (TEV) RNA which were purified by sucrose gradient centrifugation, digested with RNase, and analyzed by SDS-polyacrylamide gel electrophoresis contained proteins of 49, 32, and 24 kDa. The 49- and 24-kDa proteins reacted with polyclonal antiserum to the TEV 49-kDa proteinase while the 32-kDa protein reacted with anti-TEV serum. Further purification of the RNA by centrifugation through CsCl removed the coat protein (32 kDa), but not the 49- and 24-kDa proteins. The 49- and 24-kDa proteins did not migrate into a polyacrylamdie gel when the RNA was not digested with RNase. These results indicate that the VPg of TEV is either the 49-kDa proteinase or the 24 kDa that represents the amino-terminal half thereof.
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Affiliation(s)
- J F Murphy
- Department of Plant Pathology, University of Kentucky, Lexington 40546
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Domier LL, Franklin KM, Hunt AG, Rhoads RE, Shaw JG. Infectious in vitro transcripts from cloned cDNA of a potyvirus, tobacco vein mottling virus. Proc Natl Acad Sci U S A 1989; 86:3509-13. [PMID: 2726734 PMCID: PMC287167 DOI: 10.1073/pnas.86.10.3509] [Citation(s) in RCA: 38] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Full-length cDNA copies of tobacco vein mottling virus (TVMV) RNA were constructed downstream from bacteriophage T7 or T3 RNA polymerase promoters. The plasmids were designed to produce in vitro transcripts containing, respectively, one or two guanosine residues at the 5' terminus not derived from the TVMV sequence and a single cytidine residue at the 3' terminus following the poly(A) tail. Introduction of transcripts from either plasmid into tobacco mesophyll protoplasts resulted in the accumulation of TVMV coat protein and RNA. Neither coat protein nor viral RNA accumulated in protoplasts inoculated with linearized cDNA or with in vitro transcripts synthesized in the absence of 7-methylguanosine(5')triphospho(5')guanosine (m7GpppG). Tobacco seedlings inoculated with native TVMV RNA developed symptoms a few days before those inoculated with in vitro transcripts; however, 3 weeks after inoculation, the symptoms produced by the two inocula were indistinguishable.
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Affiliation(s)
- L L Domier
- Department of Plant Pathology, University of Kentucky, Lexington 40546
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Abstract
A cDNA fragment encoding the cytoplasmic inclusion protein of tobacco vein mottling virus was inserted into the plant expression cassette of a Ti plasmid-based binary vector. The vector was transferred to Agrobacterium tumifaciens, and following a modified leaf disc procedure, transformed tobacco plants were obtained. Analysis of poly(A)+ RNA from transgenic plants revealed a novel RNA of approximately 2100 nucleotides possessing tobacco vein mottling virus sequences. Also, immunoprecipitation of protein extracts of [35S]methionine-labeled transformed callus using anti-cytoplasmic inclusion protein antiserum revealed a polypeptide of approximately 70 kDa. This size is consistent with that predicted from the inserted tobacco vein mottling virus coding sequences. Together these data demonstrate the expression of the cytoplasmic inclusion protein in the absence of viral infections.
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Affiliation(s)
- R Graybosch
- Department of Agronomy, University of Kentucky, Lexington 40546
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47
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Abstract
Potential protease functions associated with the NIa nuclear inclusion protein of tobacco vein mottling virus (TVMV) were investigated. In the absence of treatments, in vitro translation of viral RNA produced various polypeptides representing each of the proposed TVMV cistrons--28K-HC-42K-CI-5.5K-NIa-NIb-CP. When viral RNA was first hybridized to DNA probes complementary to the NIa cistron, and then treated with RNase H prior to translation, a 48-kDa processing product, immunologically identified as the NIa protein, was abolished. In its place was observed a series of larger polypeptides, immunologically identified as fusion products of the cylindrical inclusion (CI) and NIa cistrons. The use of probes which permitted translation through as few as 15 nucleotide residues beyond the sequences encoding the proposed carboxyl terminus of NIa resulted in normal processing. None of the DNA probes affected an apparent cleavage between the helper component (HC) and 42K proteins. Cloned cDNA regions representing the NIa cistron and flanking sequences were inserted in transcription vectors. Translation of the in vitro transcript resulted in synthesis, not of a large fusion polyprotein, but, of a mature-sized NIa polypeptide. In vitro transcripts, lacking the 3'-most sequences that were expected to encode the protease active site of the NIa protein, were translated. These generated an apparent fusion polypeptide that reacted with antisera to both CI and NIa. The results indicate that the NIa gene product functions as a protease responsible for some but not all of the cleavage events which lead to the production of the mature forms of TVMV proteins.
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Affiliation(s)
- G M Hellmann
- Department of Biochemistry, University of Kentucky, Lexington 40546-0091
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48
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Abstract
The location of the cistron encoding the genome-linked protein (VPg) in the potyvirus tobacco vein mottling virus (TVMV) was investigated. Precipitation of 125I-labeled VPg with anti-tobacco etch virus 49K nuclear inclusion protein antiserum (which reacts with the NIa nuclear inclusion protein of TVMV) indicated that the TVMV VPg is immunologically related to NIa. Lysyl residues were found to be present at positions 2, 11, and 16 of the amino-terminal region of the VPg. A search of the TVMV polyprotein sequence for this distribution of lysyl residues revealed a unique location beginning at amino acid residue 1801, the proposed amino-terminus of the NIa protein.
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Affiliation(s)
- M Shahabuddin
- Department of Biochemistry, University of Kentucky, Lexington 40546
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Domier LL, Franklin KM, Shahabuddin M, Hellmann GM, Overmeyer JH, Hiremath ST, Siaw MF, Lomonossoff GP, Shaw JG, Rhoads RE. The nucleotide sequence of tobacco vein mottling virus RNA. Nucleic Acids Res 1986; 14:5417-30. [PMID: 3737407 PMCID: PMC311550 DOI: 10.1093/nar/14.13.5417] [Citation(s) in RCA: 149] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The nucleotide sequence of the RNA of tobacco vein mottling virus, a member of the potyvirus group, was determined. The RNA was found to be 9471 residues in length, excluding a 3'-terminal poly(A) tail. The first three AUG codons from the 5'-terminus were followed by in-frame termination codons. The fourth, at position 206, was the beginning of an open reading frame of 9015 residues which could encode a polyprotein of 340 kDa. No other long open reading frames were present in the sequence or its complement. This AUG was present in the sequence AGGCCAUG, which is similar to the consensus initiation sequence shared by most eukaryotic mRNAs. The chemically-determined amino acid compositions of the helper component and coat proteins were similar to those predicted from the nucleotide sequence. Amino acid sequencing of coat protein from which an amino-terminal peptide had been removed allowed exact location of the coat protein cistron. A consensus sequence of V-(R or K)-F-Q was found on the N-terminal sides of proposed cleavage sites for proteolytic processing of the polyprotein.
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Shaw JG, Johnson EC, Voyles WF, Greene ER. Noninvasive Doppler determination of cardiac output during submaximal and peak exercise. J Appl Physiol (1985) 1985; 59:722-31. [PMID: 2932418 DOI: 10.1152/jappl.1985.59.3.722] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We compared pulsed Doppler (PD) measurements of stroke volume (SV) and cardiac output (CO) as a function of work load with previously reported values that were obtained by standard invasive methods. Suprasternal notch measurements of Doppler-shifted frequency (delta f) were obtained from the ascending aorta and SV calculated with the Doppler equation and an independent measurement of aortic diameter. Motion artifacts were minimized with the aid of a restraining table cycle ergometer. Signal aliasing was accommodated with manual summation of delta f waveforms. A total of 207 determinations were made in 10 sitting subjects exercising to exhaustion. Linear regression analysis of CO vs. work load was significant (P less than 0.001). The correlation coefficient (r = 0.95) and standard error of estimate value (1.21 1/min) were similar to values from the literature. Absolute values of CO and SV underestimated the literature values across all work loads. Technical reproducibility was assessed by comparing with paired t tests the differences between 65 duplicate serial measurements of CO and SV at rest and exercise. No significant differences (P less than 0.001) were found. We concluded that PD-determined SV and CO are reproducible and correlate linearly with work load in a manner consistent with reported invasive techniques. Thus the PD method appears suitable for use during submaximal and peak exercise.
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