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Saad-Falcon A, Zhang Z, Ryoo D, Dee J, Westafer RS, Gumbart JC. Extraction of Dielectric Permittivity from Atomistic Molecular Dynamics Simulations and Microwave Measurements. J Phys Chem B 2022; 126:8021-8029. [PMID: 36171073 DOI: 10.1021/acs.jpcb.2c05260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The design of new biotechnology depends on the prediction and measurement of the electrical properties of biomolecules. The dielectric permittivity, in particular, is highly important for the design of microwave systems for diagnostics, yet this property is rarely explicitly targeted during the development of biomolecular force fields for molecular dynamics (MD) simulations. In order to explore the ability of existing force fields to reproduce the frequency-dependent permittivity, we carried out MD simulations of various aqueous solutions, including pure water, isopropyl alcohol, alanine, and the protein ubiquitin. The TIP3P, TIP4P, TIP4P/ε, and SWM4-NDP water models were used along with the CHARMM36m and Drude protein force fields. An experimental setup using a truncated coaxial line was created to measure the permittivity of the same solutions to check for measure-model agreement. We found that one of the nonpolarizable force fields (TIP4P/ε + CHARMM36m) and the polarizable force fields (SWM4-NDP + Drude) closely agree with experimental results. This demonstrates the strength of the tuned TIP4P/ε water model, as well as the physical validity of polarizable force fields in capturing dielectric permittivity. This represents an important step toward the predictive design of biosensors.
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Affiliation(s)
- Alex Saad-Falcon
- Georgia Tech Research Institute, Atlanta, Georgia 30332, United States
| | - Zijian Zhang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - David Ryoo
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - James Dee
- Georgia Tech Research Institute, Atlanta, Georgia 30332, United States
| | - Ryan S Westafer
- Georgia Tech Research Institute, Atlanta, Georgia 30332, United States
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Brüse S, Dee J, Prieur WD. Internal Fixation with a Veterinary Cuttable Plate in Small Animals. Vet Comp Orthop Traumatol 2018. [DOI: 10.1055/s-0038-1633188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Summary63 cases (42 cats, 21 dogs) were treated with a newly developed plate that can be cut during surgery to the required length and may be sandwiched if one plate is not rigid enough. The plate is manufactured in lengths of 30 cm and in two different thicknesses, 1.0 mm and 1.5 mm. The thinner plate is used with 1.5 mm or 2.0 mm Cortex screws and the thicker one with 2.0 or 2.7 mm Cortex screws. Healing was generally uneventful with the exceptions noted.
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Gonese E, Mushavi A, Mungati M, Mhangara M, Dzangare J, Mugurungi O, Dee J, Kilmarx PH, Shambira G, Tshimanga MT, Hargrove J. Is Zimbabwe ready to transition from anonymous unlinked sero-surveillance to using prevention of mother to child transmission of HIV (PMTCT) program data for HIV surveillance?: results of PMTCT utility study, 2012. BMC Infect Dis 2016; 16:97. [PMID: 26923185 PMCID: PMC4770682 DOI: 10.1186/s12879-016-1425-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [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: 10/09/2015] [Accepted: 02/10/2016] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Prevention of mother-to-child transmission of HIV (PMTCT) programs collect socio-demographic and HIV testing information similar to that collected by unlinked anonymous testing sero-surveillance (UAT) in antenatal settings. Zimbabwe evaluated the utility of PMTCT data in replacing UAT. METHODS A UAT dataset was created by capturing socio-demographic, testing practices from the woman's booking-card and testing remnant blood at a laboratory from 1 June to 30 September 2012. PMTCT data were collected retrospectively from ANC registers. UAT and PMTCT data were linked by bar-code labels that were temporarily affixed to the ANC register. A questionnaire was used to obtain facility-level data at 53 sites. RESULTS Pooled HIV prevalence was 15.8 % (95 % CI 15.3-16.4) among 17,349 women sampled by UAT, and 16.3 % (95 % CI 15.8 %-16.9 %) among 17,150 women in PMTCT datasets for 53 sites. Pooled national percent-positive agreement (PPA) was 91.2 %, and percent-negative agreement (PNA) was 98.7 % for 16,782 women with matched UAT and PMTCT data. Based on UAT methods, overall median prevalence was 12.9 % (Range 4.0 %-19.4 %) among acceptors and refusers of HIV test in PMTCT compared to 12.5 % ((Range 3.4 %-19.5 %) among acceptors in ANC registers. There were variations in prevalence by site. CONCLUSION Although, there is no statistical difference between pooled HIV prevalence in UAT compared to PMTCT program, the overall PPA of 91.2 % and PNA of 98.7 % fall below World Health Organisation (WHO) benchmarks of 97.6 % and 99.6 % respectively. Zimbabwe will need to strengthen quality assurance (QA) of rapid HIV testing and data collection practices. Sites with good performance should be prioritised for transitioning.
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Affiliation(s)
- E Gonese
- Centers for Disease Control and Prevention, 38 Nelson Mandela Rd, Box 3088, Harare, Zimbabwe.
| | - A Mushavi
- Ministry of Health and Child Care Zimbabwe, Mukwati Building, Corner Livingstone/Fifth Street, Harare, Zimbabwe.
| | - M Mungati
- Ministry of Health and Child Care Zimbabwe, Mukwati Building, Corner Livingstone/Fifth Street, Harare, Zimbabwe.
| | - M Mhangara
- Ministry of Health and Child Care Zimbabwe, Mukwati Building, Corner Livingstone/Fifth Street, Harare, Zimbabwe.
| | - J Dzangare
- Ministry of Health and Child Care Zimbabwe, Mukwati Building, Corner Livingstone/Fifth Street, Harare, Zimbabwe.
| | - O Mugurungi
- Ministry of Health and Child Care Zimbabwe, Mukwati Building, Corner Livingstone/Fifth Street, Harare, Zimbabwe.
| | - J Dee
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329-4027, USA.
| | - P H Kilmarx
- National Institute of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
| | - G Shambira
- Department of Community Medicine, University of Zimbabwe, Parirenyatwa Hospital, Mazoe Street, Harare, Zimbabwe.
| | - M T Tshimanga
- Department of Community Medicine, University of Zimbabwe, Parirenyatwa Hospital, Mazoe Street, Harare, Zimbabwe.
| | - J Hargrove
- South Africa Centre for Epidemiological Modelling and Analysis, Stellenbosch University, 19 Jonkershoek Road, Stellenbosch, 7602, South Africa.
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Chang C, Stoytcheva Z, Marh J, Dee J, Fogelgren B, Lozanoff S, Moisyadi S. Insertion of a functional copy of six2 into the mouse genome to examine prenatal morphogenetic factors leading to chronic renal failure in the adult. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.962.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Cara Chang
- Cell and Molecular BiologyJohn A. Burns School of MedicineHonoluluHI
| | - Zoia Stoytcheva
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
| | - Joel Marh
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
| | - James Dee
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
| | - Ben Fogelgren
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
| | - Scott Lozanoff
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
| | - Stefan Moisyadi
- Anatomy, Biochemistry and PhysiologyJohn A. Burns School of MedicineHonoluluHI
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Vile J, Carta M, Bezzu CG, Dee J, McKeown NB. The unexpected formation of a dihydroisobenzofuran derivative from the addition of a Grignard reagent to a 1,3-indanedione. ARKIVOC 2012. [DOI: 10.3998/ark.5550190.0013.712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Dee J. Doing the right thing at the right time. BMJ Support Palliat Care 2011. [DOI: 10.1136/bmjspcare-2011-000105.136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Ho D, Moskowitz K, Sum R, Dee J, Rudolph A, Burch C, Pebley W, Orser C. 072
Wound Healing Properties of Reconstituted Freeze-Dried Platelets. Wound Repair Regen 2008. [DOI: 10.1111/j.1067-1927.2005.130215bt.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Everglades virus (EVEV), an alphavirus in the Venezuelan equine encephalitis complex, circulates among rodents and vector mosquitoes in Florida and occasionally infects humans. It causes febrile disease, sometimes accompanied by neurologic manifestations. Although previous surveys showed high seroprevalence in humans, EVEV infections may be underdiagnosed because the disease is not severe enough to warrant a clinic visit or the undifferentiated presentations complicate diagnosis. Documented EVEV activity, as recent as 1993, was limited to south Florida. Using dogs as sentinels, a serosurvey was conducted to evaluate whether EVEV circulated recently in Florida and whether EVEV's spatial distribution parallels that of the mosquito vector, Culex cedecei. Four percent of dog sera contained neutralizing EVEV antibodies, and many seropositive animals lived farther north than both recorded EVEV activity and the principal vector. These results indicate that EVEV is widespread in Florida and may be an important, unrecognized cause of human illness.
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Affiliation(s)
- Lark L. Coffey
- University of Texas Medical Branch, Galveston, Texas, USA
| | | | - James Dee
- Hollywood Animal Hospital, Hollywood, Florida, USA
| | - Ryan Miller
- Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
| | - Jerome Freier
- Animal and Plant Health Inspection Service, Fort Collins, Colorado, USA
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Slawson EE, Shaffer CD, Malone CD, Leung W, Kellmann E, Shevchek RB, Craig CA, Bloom SM, Bogenpohl J, Dee J, Morimoto ETA, Myoung J, Nett AS, Ozsolak F, Tittiger ME, Zeug A, Pardue ML, Buhler J, Mardis ER, Elgin SCR. Comparison of dot chromosome sequences from D. melanogaster and D. virilis reveals an enrichment of DNA transposon sequences in heterochromatic domains. Genome Biol 2006; 7:R15. [PMID: 16507169 PMCID: PMC1431729 DOI: 10.1186/gb-2006-7-2-r15] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 09/15/2005] [Accepted: 01/25/2006] [Indexed: 11/10/2022] Open
Abstract
Sequencing and analysis of fosmid hybridization to the dot chromosomes of Drosophila virilis and D. melanogaster suggest that repetitive elements and density are important in determining higher-order chromatin packaging. Background Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago. Results Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %). Conclusion Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging.
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Affiliation(s)
| | | | - Colin D Malone
- Biology Department, Washington University, St Louis, MO 63130, USA
| | - Wilson Leung
- Biology Department, Washington University, St Louis, MO 63130, USA
| | - Elmer Kellmann
- Biology Department, Washington University, St Louis, MO 63130, USA
| | | | - Carolyn A Craig
- Biology Department, Washington University, St Louis, MO 63130, USA
| | - Seth M Bloom
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - James Bogenpohl
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - James Dee
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Emiko TA Morimoto
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Jenny Myoung
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Andrew S Nett
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Fatih Ozsolak
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Mindy E Tittiger
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Andrea Zeug
- Member, Bio 4342 class, Washington University, St Louis, MO 63130, USA
| | - Mary-Lou Pardue
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jeremy Buhler
- Computer Science and Engineering, Washington University, St Louis, MO 63130, USA
| | - Elaine R Mardis
- Genome Sequencing Center and Department of Genetics, Washington University, St Louis, MO 63108, USA
| | - Sarah CR Elgin
- Biology Department, Washington University, St Louis, MO 63130, USA
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Dee J. Assessing the efficacy of perioperative carprofen administration in dogs undergoing surgical repair of a ruptured cranial cruciate ligament. J Am Anim Hosp Assoc 2001; 37:115. [PMID: 11300515 DOI: 10.5326/15473317-37-2-115] [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] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bailey J, Cook LJ, Kilmer-Barber R, Swanston E, Solnica-Krezel L, Lohman K, Dove WF, Dee J, Anderson RW. Identification of three genes expressed primarily during development in Physarum polycephalum. Arch Microbiol 1999; 172:364-76. [PMID: 10591846 DOI: 10.1007/s002030050773] [Citation(s) in RCA: 9] [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: 10/28/2022]
Abstract
During the life cycle of Physarum polycephalum, uninucleate amoebae develop into multinucleate syncytial plasmodia. These two cell types differ greatly in cellular organisation, behaviour and gene expression. Classical genetic analysis has identified the mating-type gene, matA, as the key gene controlling the initiation of plasmodium development, but nothing is known about the molecular events controlled by matA. In order to identify genes involved in regulating plasmodium formation, we constructed a subtracted cDNA library from cells undergoing development. Three genes that have their highest levels of expression during plasmodium development were identified: redA, redB (regulated in development) and mynD (myosin). Both redA and redB are single-copy genes and are not members of gene families. Although redA has no significant sequence similarities to known genes, redB has sequence similarity to invertebrate sarcoplasmic calcium-binding proteins. The mynD gene is closely related to type II myosin heavy-chain genes from many organisms and is one of a family of type II myosin genes in P. polycephalum. Our results indicate that many more red genes remain to be identified, some of which may play key roles in controlling plasmodium formation.
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Affiliation(s)
- J Bailey
- McArdle Laboratory for Cancer Research, 1400 University Avenue, Madison, WI 53706, USA.
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Abstract
Fast 60 degree head rotations of nine patients with cerebellar deficits were analysed and compared with those of nine normal subjects. The surface EMG activity from both Splenii capitis muscles were recorded. The triphasic pattern of reciprocal innervated neck muscles with regard to the duration, amplitude and onset of the pulses were analysed together with the dynamic features of head rotation, i.e. position and acceleration profiles. The deviation of the onset of the antagonistic (B) pulse of the EMG-pattern flow was substantially increased. In most cases the onset of the B-pulse was delayed, less premature and sporadic regular onsets occurred. The number of co-contractions and multiple antagonistic pulses was significantly increased. Half of the movements of patients were found to be dysmetric, with an irregular flow of position and acceleration functions. From these, mainly hypermetric movements occurred. The number of irregular pulse patterns was higher than the number of dysmetrias. In this context cocontractions, multiple antagonistic pulses and cortical control can be discussed as strategies of the cerebellar patients to improve their dynamic output. Our experiments support the notion of the cerebellum playing an important part in the temporal integration of an antagonistically innervated movement. The measurement of electromyographic burst patterns can be used as a clinical tool to demonstrate an insufficient timing of the activities of muscles involved.
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Affiliation(s)
- J Dee
- Neurological Clinic, University Hospital Eppendorf, University of Hamburg, Germany
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13
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Abstract
Amoebae of the Myxomycete Physarum polycephalum form resistant, walled cysts when the food bacteria in a culture have been consumed. No G1 phase has been detected in the vegetative amoebal cell cycle, most of which comprises the G2 phase. Mature cysts are also in G2, but it has been reported that a G1 phase of roughly 24 h, followed by an S phase, is obligatory prior to encystment. We used flow cytometry to determine the distribution of DNA contents in amoebal cultures at intervals during vegetative growth and encystment. In all cultures, the cells were predominantly in G2 phase, and the percentage of cells with G1 DNA content remained very low. We conclude that an extended G1 phase of 24 h did not occur in our cultures and cannot be a prerequisite for encystment.
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Affiliation(s)
- R W Anderson
- Department of Molecular Biology and Biotechnology, University of Sheffield, United Kingdom.
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, Cormier T, Dadusc G, David G, Dee J, Dietzsch O, Fatyga M, Greene SV, Germani JV, Hall JR, Hemmick TK, Herrmann N, Hogue RW, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam TW, Majka R, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Simon-Gillo J, Sonnadara U, Stachel J, Takai H, Takagui EM, Throwe TG, Waters L, Winter C, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Search for pion-neutron bound states in 14.6A GeV Si + nucleus collisions. Phys Rev C Nucl Phys 1995; 52:2679-2683. [PMID: 9970798 DOI: 10.1103/physrevc.52.2679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, Cormier T, David G, Dee J, Diebold GE, Dietzsch O, Germani JV, Gilbert S, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam T, Majka R, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rosati M, Rotondo FS, Sonnadara U, Stachel J, Takai H, Takagui EM, Wang G, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Tranverse energy and charged particle multiplicity in p-nucleus collisions at 14.6 GeV/c. Phys Rev C Nucl Phys 1995; 52:2028-2036. [PMID: 9970719 DOI: 10.1103/physrevc.52.2028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, David G, Dee J, Dietzsch O, Duek E, Fatyga M, Fox D, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam T, Mark SK, McCorkle S, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Simon-Gillo J, Sonnadara U, Stachel J, Takagui EM, Takai H, Throwe TG, Waters L, Winter C, Wolf K, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Production of neutron-rich isotopes from the fragmentation of 28Si projectiles at plab=14.6 GeV/c per nucleon. Phys Rev C Nucl Phys 1995; 52:956-963. [PMID: 9970585 DOI: 10.1103/physrevc.52.956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Barrette J, Bellwied R, Bennett S, Braun-Munzinger P, Cleland WE, Clemen M, Cole JD, Cormier TM, David G, Dee J, Dietzsch O, Drigert MW, Hall JR, Hemmick TK, Herrmann N, Hong B, Kwon Y, Lacasse R, Lukaszew A, Li Q, Ludlam TW, Mark SK, McCorkle S, Matheus R, Murgatroyd JT, O'Brien E, Panitkin S, Piazza T, Pruneau C, Rao MN, Rosati M, daSilva NC, Sedykh S, Sonnadara U, Stachel J, Starinsky N, Takagui EM, Voloshin S, Wang G, Wessels JP, Woody CL, Xu N, Zhang Y, Zou C. Charged-particle pseudorapidity distributions in Au+Al, Cu, Au, and U collisions at 10.8A GeV/c. Phys Rev C Nucl Phys 1995; 51:3309-3319. [PMID: 9970434 DOI: 10.1103/physrevc.51.3309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Solnica-Krezel L, Bailey J, Gruer DP, Price JM, Dove WF, Dee J, Anderson RW. Characterization of npf mutants identifying developmental genes in Physarum. Microbiology (Reading) 1995; 141 ( Pt 4):799-816. [PMID: 7773386 DOI: 10.1099/13500872-141-4-799] [Citation(s) in RCA: 3] [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: 01/27/2023]
Abstract
In Physarum polycephalum, uninucleate haploid amoebae develop into macroscopic multinucleate plasmodia. Wild-type, sexual development is triggered when two amoebae carrying different alleles of matA fuse to form a zygote which develops into a diploid plasmodium. Mutations in the matA genetic region give rise to apogamic strains in which a single haploid amoeba can develop into a haploid plasmodium. An essential stage in both sexual and apogamic plasmodium formation is an extended cell cycle in uninucleate cells, which ends with the formation of a binucleate cell by mitosis without cytokinesis. Using a 'brute force' screening method, we have isolated mutants blocked in apogamic plasmodium development. Genetic analysis showed that the mutations we have identified were unlinked to matA, unlike mutations previously identified following an enrichment step. Most of the loci revealed by our screen were represented by only one allele, indicating that further screening should lead to the identification of additional genes required for plasmodium development. Phenotypic analysis showed that different mutants were blocked at different stages of plasmodium formation. Some of the mutations blocking apogamic development at an early stage, close to the start of the long cell cycle, failed to block sexual development in zygotes homozygous for the mutation. Since the two modes of plasmodium formation differ only in the initiation of development, these mutations presumably interfere with the initiation process. In the remaining mutants, in which both sexual and apogamic development were blocked, development first became abnormal towards the end of the long cell cycle. This suggested that the wild-type gene products were required by this time and was consistent with previous evidence that many changes in cellular organization and gene expression occur during the long cell cycle. Each of these mutants showed a different terminal phenotype and some aspects of plasmodium development occurred normally although others were blocked, suggesting that development involves multiple pathways rather than a dependent sequence of events. Phenotypic analysis of double mutants supported this conclusion and also revealed epistatic interactions, presumably due to blocks in the same pathway. In several of the mutants, terminally differentiated cells died by an apoptosis-like mechanism; since this was never observed in vegetative cells, it was presumably triggered by the failure of development. Phenotypic analyses of additional mutants will extend our understanding of the pathways involved in plasmodium development.
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, David G, Dee J, Dietzsch O, Duek E, Fatyga M, Fox D, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam T, Mark SK, McCorkle S, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Simon-Gillo J, Sonnadara U, Stachel J, Takagui EM, Takai H, Throwe TG, Waters L, Winter C, Wolf K, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Electromagnetic dissociation of relativistic 28Si. Phys Rev C Nucl Phys 1995; 51:865-878. [PMID: 9970131 DOI: 10.1103/physrevc.51.865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
The objective of this research is to explore the role of the cerebellum in the human motor control system. The present study quantitatively compares the neurological control signals effecting fast, horizontal head rotations in normal subjects to those in patients with a cerebellar lesion. The method involves the use of a computer simulation model for one degree-of-freedom movements. A method for unconstrained global optimization, first proposed by Hans Bremermann (1970), is used to identify the timing and magnitudes of the input neurological control signals to the model, which are compared to recorded electromyograms (EMGs). Experimentally recorded kinematics from cerebellar patients and from normal subjects were used to drive the parameter search. These simulations found that cerebellar patients' neurological control signals were altered with respect to those of normal subjects, and suggest that the electromyographic activity of cerebellar patients may comprise at least five bursts of activity whereas normal subjects typically exhibit only three. The results are discussed with respect to the hypothesis that the cerebellum may be involved in both the timing and magnitudes of the neurological control signals effecting voluntary movement.
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Affiliation(s)
- C F Ramos
- Neurology Unit, School of Optometry, University of California, Berkeley 94720, USA
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21
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, Cormier TM, David G, Dee J, Diebold GE, Dietzsch O, Germani JV, Gilbert S, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam TW, McCorkle S, Majka R, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rao MN, Rotondo F, daSilva NC, Sonnadara U, Stachel J, Takai H, Takagui EM, Throwe TG, Winter C, Wang G, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Centrality dependence of longitudinal and transverse baryon distributions in ultrarelativistic nuclear collisions. Phys Rev C Nucl Phys 1994; 50:3047-3059. [PMID: 9970007 DOI: 10.1103/physrevc.50.3047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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22
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Barrette J, Bellwied R, Bennett S, Braun-Munzinger P, Cleland WE, Clemen M, Cole J, Cormier TM, David G, Dee J, Dietzsch O, Drigert M, Gilbert S, Hall JR, Hemmick TK, Herrmann N, Hong B, Jiang CL, Kwon Y, Lacasse R, Lukaszew A, Li Q, Ludlam TW, McCorkle S, Mark SK, Matheus R, O'Brien E, Panitkin S, Piazza T, Pruneau C, Rao MN, Rosati M, daSilva NC, Sedykh S, Sonnadara U, Stachel J, Takai H, Takagui EM, Voloshin S, Wang G, Wessels JP, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Observation of anisotropic event shapes and transverse flow in ultrarelativistic Au+Au collisions. Phys Rev Lett 1994; 73:2532-2535. [PMID: 10057084 DOI: 10.1103/physrevlett.73.2532] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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23
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Abstract
Actin-myosin interaction kinetics of the intact rat portal vein were studied by analyzing force recovery after cessation of force-inhibiting length vibration. The time constant of postvibration force recovery averaged 0.86 +/- 0.04 s during short-term activation (< 12 s), and increased up to 1.59 +/- 0.02 s (cross-bridge downregulation) during sustained activation of more than 10 min. After the depletion of intracellular calcium stores, the depolarized preparation developed maximum force at an extracellular calcium concentration in excess of 50 mM CaCl2. The time constant of postvibration force recovery rose to 12.31 +/- 1.35 s after an activation period of 30 min. These retarded contraction kinetics may be caused either by low activation of the 20-kDa myosin light chain kinase or by high activity of the 20-kDa myosin light chain phosphatase. Addition of the phosphatase inhibitor okadaic acid (10 microM) during high calcium activation decreases the time constant to 8.04 +/- 0.86 s and appears to prevent the distinct retardation of the contraction kinetics. During submaximum activation (2.5 mM CaCl2), the time constant of postvibration force recovery stabilizes at 1.56 +/- 0.07 s, indicating downregulated cross-bridge kinetics, and is unaffected by phosphatase inhibition. For maximum barium activation, instead of calcium, 19.5 mM BaCl2 is required, which produced time constants of postvibration force recovery of 8.38 +/- 0.32 s. The addition of okadaic did not affect contraction kinetics during barium activation. The pronounced retardation of contraction kinetics that was observed after the maximum calcium activation of the previously calcium depleted, depolarized preparation is probably due to high phosphatase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- U Peiper
- Institute of Physiology, University Hospital Eppendorf, University of Hamburg, Germany
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, Cormier TM, David G, Dee J, Diebold GE, Dietzsch O, Germani JV, Gilbert S, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam TW, McCorkle S, Majka R, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Sandweiss J, daSilva NC, Sonnadara U, Stachel J, Takai H, Takagui EM, Throwe TG, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Production of light nuclei in relativistic heavy-ion collisions. Phys Rev C Nucl Phys 1994; 50:1077-1084. [PMID: 9969750 DOI: 10.1103/physrevc.50.1077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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25
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, David G, Dee J, Dietzsch O, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam T, Majka R, Mark SK, McCorkle S, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Sonnadara U, Stachel J, Takagui EM, Takai H, Throwe TG, Voloshin S, Waters L, Winter C, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Two charged particle and transverse energy correlations in Si+Pb collisions at 14.6A GeV/c. Phys Rev C Nucl Phys 1994; 49:1669-1683. [PMID: 9969389 DOI: 10.1103/physrevc.49.1669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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26
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Barrette J, Bellwied R, Bennett S, Braun-Munzinger P, Cleland WE, Cormier TM, David G, Dee J, Diebold GE, Dietzsch O, Fox D, Germani JV, Gilbert S, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Li Q, Lissauer D, Llope WJ, Ludlam TW, McCorkle S, Majka R, Mark SK, Matheus R, Mitchell JT, Muthuswamy M, O'Brien E, Panitkin S, Pruneau C, Rao MN, Rosati M, Rotondo F, daSilva NC, Simon-Gillo J, Sonnadara U, Stachel J, Sullivan J, Takai H, Takagui EM, Throwe TG, Winter C, Wang G, Wolf KL, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Measurement of transverse energy production with Si and Au beams at relativistic energy: Towards hot and dense hadronic matter. Phys Rev Lett 1993; 70:2996-2999. [PMID: 10053749 DOI: 10.1103/physrevlett.70.2996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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27
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, Cormier T, Dadusc G, David G, Dee J, Diebold GE, Dietzsch O, Duek E, Fatyga M, Fox D, Greene SV, Germani JV, Hall JR, Hemmick TK, Herrmann N, Hogue RW, Hong B, Jayananda K, Kraus D, Kumar BS, Lacasse R, Lissauer D, Llope WJ, Ludlam TW, Majka R, Makowiecki D, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Pruneau C, Rotondo FS, Sandweiss J, Simon-Gillo J, Slaughter J, Sonnadara U, Stachel J, Takai H, Takagui EM, Throwe TG, Waters L, Winter C, Wolf K, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou C. Antiproton production in relativistic Si-nucleus collisions. Phys Rev Lett 1993; 70:1763-1766. [PMID: 10053380 DOI: 10.1103/physrevlett.70.1763] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Abstract
In Physarum, microscopic uninucleate amoebae develop into macroscopic multinucleate plasmodia. In the mutant strain, RA614, plasmodium development is blocked. RA614 carries a recessive mutation (npfL1) in a gene that functions in sexual as well as apogamic development. In npfL+ apogamic development, binucleate cells arise from uninucleate cells by mitosis without cytokinesis at the end of an extended cell cycle. In npfL1 cultures, apogamic development became abnormal at the end of the extended cell cycle. The cells developed a characteristic rounded, vacuolated appearance, nuclear fusion and vigorous cytoplasmic motion occurred, and the cells eventually died. Nuclei were not visible by phase-contrast microscopy in most of the abnormally developing cells, but fluorescence microscopy after DAPI staining revealed intensely staining, condensed nuclei without nucleoli. Studies of tubulin organization during npfL1 development indicated a high frequency of abnormal mitotic spindles and, in some interphase cells, abnormally thick microtubules. Some of these features were observed at low frequency in the parental npfL+ strain and may represent a pathway of cell death, resembling apoptosis, that may be triggered in more than one way. Nuclear fusion occurred during interphase and mitosis in npfL1 cells, and multipolar spindles were also observed. None of these features were observed in npfL+ cells, suggesting that a specific effect of the npfL1 mutation may be an incomplete alteration of nuclear structure from the amoebal to the plasmodial state.
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Affiliation(s)
- J Bailey
- Department of Genetics, University of Leicester, UK
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Bailey J, Solnica-Krezel L, Lohman K, Dee J, Anderson RW, Dove WF. Cellular and molecular analysis of plasmodium development in Physarum. Cell Biol Int Rep 1992; 16:1083-90. [PMID: 1490279 DOI: 10.1016/s0309-1651(05)80033-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The development of an amoeba into a plasmodium involves extensive changes in cellular organisation and gene expression. The genetic basis of a number of recessive mutations that block plasmodium development has been elucidated. The stage at which development becomes abnormal has been determined for all the mutants, as has the terminal phenotype. In order to investigate the changes in gene expression that accompany plasmodium development, a cDNA library has been made using RNA isolated from cell populations in which development was occurring.
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Affiliation(s)
- J Bailey
- McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, David G, Dee J, Dietzsch O, Duek E, Fatyga M, Fox D, Greene SV, Hall JR, Hemmick TK, Herrmann N, Hogue RW, Hong B, Jayananda K, Kraus D, Lacasse R, Lissauer D, Llope WJ, Ludlam T, Majka R, Makowiecki D, Mark SK, McCorkle S, Mitchell JT, Muthuswamy M, O'Brien E, Polychronakos V, Pruneau C, Rotondo FS, Sandweiss J, Simon-Gillo J, Sonnadara U, Stachel J, Takai H, Takagui EM, Throwe TG, Waters L, Willis WJ, Winter C, Wolf K, Wolfe D, Woody CL, Xu N, Zhang Y, Zhang Z, Zou Z. Electromagnetic dissociation of relativistic 28Si into p+27Al. Phys Rev C Nucl Phys 1992; 45:2427-2437. [PMID: 9968007 DOI: 10.1103/physrevc.45.2427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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31
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Barrette J, Bellwied R, Braun-Munzinger P, Cleland WE, David G, Dee J, Fatyga M, Fox D, Greene SV, Hall J, Hemmick TK, Heifetz R, Herrmann N, Hogue RW, Ingold G, Jayananda K, Kraus D, Lisa M, Lissauer D, Llope WJ, Ludlam T, Majka R, Makowiecki D, Mark SK, Mitchell JT, Muthuswamy M, O'Brien E, Polychronakos V, Pruneau C, Rotondo F, Sandweiss J, Simon J, Sonnadara U, Stachel J, Takai H, Throwe T, Waters L, Winter C, Woody C, Wolf K, Wolfe D, Zhang Y. Forward baryons in relativistic nucleus-nucleus collisions. Phys Rev C Nucl Phys 1992; 45:819-832. [PMID: 9967819 DOI: 10.1103/physrevc.45.819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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32
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Frazier K, Herron AJ, Dee J, Ghandur-Mnymneh L, Altman NH. Development of small-cell osteogenic sarcoma after ulnar ostectomy in a dog. J Am Vet Med Assoc 1991; 198:432-4. [PMID: 2010337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A 5-year-old male Saint Bernard was evaluated for vague forelimb lameness. Four and a half years earlier, the dog had undergone left ulnar ostectomy to correct a valgus deformity. Focal bone lysis was evident radiographically at the ostectomy site. Four months later, marked bony swelling was apparent and the dog was bearing partial weight. The dog was euthanatized, and at necropsy, a bone tumor with lung metastasis was found. Microscopically, features of the tumor were compatible with those of small-cell osteogenic sarcoma.
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Bailey J, Anderson RW, Dee J. Cellular events during sexual development from amoeba to plasmodium in the slime mould Physarum polycephalum. J Gen Microbiol 1990; 136:739-51. [PMID: 2398347 DOI: 10.1099/00221287-136-4-739] [Citation(s) in RCA: 7] [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: 12/31/2022]
Abstract
Time-lapse cinematography and immunofluorescence microscopy were used to study cellular events during amoebal fusions and sexual plasmodium development in Physarum polycephalum. Amoebal fusions occurred frequently in mixtures of strains heteroallelic or homoallelic for the mating-type locus matA, but plasmodia developed only in the matA-heteroallelic cultures. These observations confirmed that matA controls development of fusion cells rather than cell fusion. Analysis of cell pedigrees showed that, in both types of culture, amoebae fused at any stage of the cell cycle except mitosis. In matA-heteroallelic fusion cells, nuclear fusion occurred in interphase about 2 h after cell fusion; interphase nuclear fusion did not occur in matA-homoallelic fusion cells. The diploid zygote, formed by nuclear fusion in matA-heteroallelic fusion cells, entered an extended period of cell growth which ended in the formation of a binucleate plasmodium by mitosis without cytokinesis. In contrast, no extension to the cell cycle was observed in matA-homoallelic fusion cells and mitosis was always accompanied by cytokinesis. In matA-homoallelic cultures, many of the binucleate fusion cells split apart without mitosis, regenerating pairs of uninucleate amoebae; in the remaining fusion cells, the nuclei entered mitosis synchronously and spindle fusion sometimes occurred, giving rise to a variety of products. Immunofluorescence microscopy showed that matA-heteroallelic fusion cells possessed two amoebal microtubule organizing centres, and that most zygotes possessed only one; amoebal microtubule organization was lost gradually over several cell cycles. In matA-homoallelic cultures, all the cells retained amoebal microtubule organization.
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Affiliation(s)
- J Bailey
- Department of Genetics, University of Leicester, UK
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Abstract
Acetabular fractures in 26 racing Greyhounds were reviewed. All fractures occurred during racing or training and were unrelated to any external trauma. All fractures had similar configurations, were minimally displaced, and involved only the acetabulum. Affected dogs were young (16-36 months). Fractures occurred unilaterally (22 dogs) and bilaterally (4 dogs). There was no sex predilection, and both right and left sides were equally represented. Bilateral fractures were associated with retraining between the occurrence of the first and second fractures. Radiographically, a fracture line was consistently visible in the caudal third of the acetabulum. Fractures in gross specimens resembled an inverted "Y." Results of histologic evaluation of two fractured acetabula showed changes characteristic of a nonunion fracture. Microfractures were evident in the grossly normal acetabulum opposite the fractured side. Evidence obtained from this study suggests a common pathogenesis of the fractures related to tremendous repetitive stresses produced during running. Greyhounds with unilateral acetabular fractures may provide a reproducible model for future studies of stress fractures in animals and humans because of the high incidence of bilateral fractures that develop during retraining. Surgical repair of the acetabular stress fracture was more successful than conservative management in returning the dogs to competitive racing.
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Affiliation(s)
- K Wendelburg
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus
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Burland TG, Chainey AM, Dee J, Foxon JL. Analysis of development and growth in a mutant of Physarum polycephalum with defective cytokinesis. Dev Biol 1981; 85:26-38. [PMID: 7250516 DOI: 10.1016/0012-1606(81)90233-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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36
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Turnock G, Morris SR, Dee J. A comparison of the proteins of the amoebal and plasmodial phases of the slime mould, Physarum polycephalum. Eur J Biochem 1981; 115:533-8. [PMID: 6786886 DOI: 10.1111/j.1432-1033.1981.tb06235.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
1. The proteins of amoebae and plasmodia of strain CL of Physarum polycephalum have been compared by two-dimensional gel electrophoresis. Both forms of the organism were labelled by growth on formalin-killed bacteria labelled with [35S]sulphate, [3H]lysine or [14C]lysine. Plasmodia were also labelled from radioactive lysine in the medium. 2. Of 306 relatively abundant proteins examined, 26% were phase-specific, that is they were found only in amoebae or in plasmodia. About a quarter of these apparent differences in gene expression may be due to minor changes in charge and/or size. 3. Amongst the 74% of the proteins present in both amoebae and plasmodia, there are substantial differences in differential rates of synthesis and these have been measured for a representative set of proteins by a double-label procedure.
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Abstract
Asynchronous amoebal cultures of temperature-sensitive mutants of Physarum polycephalum were examined cytologically, and two cell cycle mutants were identified. Genetic analysis indicated that each mutant carried a single mutation that was expressed in both amoebal and plasmodial phases. Thus it is possible to isolate cell cycle mutations expressed in plasmodia by initial isolation and analysis of amoebal mutants, a quicker procedure than the alternative of isolating plasmodial mutants directly. The two mutants were studied further by measuring nuclear DNA contents and synthesis of macromolecules. Both mutants gave results consistent with a block in nuclear division.
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Abstract
SUMMARYOver 100 temperature-sensitive mutants ofmt-h (apogamic) strains ofPhysarum polycephalumwere isolated either by testing clones of mutagenized amoebae (ATS mutants) or by the more laborious method of testing plasmodia derived from such clones (PTS mutants). When amoebae and plasmodia of each mutant were tested for growth temperature sensitivity on different media (to give optimum growth of each phase), only 21% of 73 ATS mutants and 32% of 31 PTS mutants appeared to be temperature-sensitive in both phases, suggesting that the majority of mutants are phase-specific, as concluded from several similar studies by previous authors. When the mutants were tested on a third medium which allows growth of both amoebae and plasmodia, many of the mutants no longer had a temperature-sensitive phenotype in either phase. Among the remainder, 51% of ATS mutants and 67% of PTS mutants were temperature-sensitive in both phases. It was suggested that certain media have a remedial effect on some temperature-sensitive mutants so that the phenotype is apparently normal. Thus, the proportion of phase-specific mutants may be over-estimated if tests of temperature-sensitivity are done on the different media commonly used for culture of amoebae and plasmodia respectively. It was concluded that the most efficient procedure for isolation of temperature-sensitive mutants expressed in plasmodia is to screen clones of amoebae on a medium resembling as closely as possible that which is to be used for testing plasmodia.
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Abstract
Amoebae of the true slime mould Physarum polycephalum were cultured in two fully-defined liquid media containing amino acids, glucose, three vitamins and a buffered salts solution. Absolute requirements were demonstrated for methionine, haematin, thiamine and biotin, all of which were known to be specific requirements of the plasmodial stage. Methods are described for large-scale culture in three semi-defined media.
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Abstract
SUMMARYAmoebae of the Colonia isolate ofPhysarum polycephalumproduce plasmodia within individual amoebal clones.This paper reports the derivation from the Colonia strainC50 of a strainCL(Colonia Leicester) which produces plasmodia in clones with high efficiency and which completes the life cycle reliably and repeatedly in single clones. The derivation of a lineCLd (CLdelayed plasmodium formation) is described and, usingCLd, the construction of the isogenic heterothallic strainsmt1;CLandmt2;CL.The above strains provide a system for the isolation and genetic analysis of mutants ofP. polycephalumwithin a uniform genetic background, in particular mutants expressed in the plasmodium.Using this system two auxotrophic mutants have been isolated. Preliminary genetic analysis has shown that they are due to single gene mutations.
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Abstract
SUMMARYThe Colonia isolate ofPhysarum polycephalumproduces plasmodia within amoebal clones. Wheals demonstrated genetically that amoebae of the C50 strain of this isolate, when crossed with heterothallic amoebae, yielded recombinant progeny. He concluded that nuclear fusion and meiosis occurred in these crosses and suggested that nuclear fusion was also involved in plasmodia formation in clones. He thus designated the strain ‘homothallic’.In the present work genetic evidence is presented which indicates that the Colonia strainCL, when crossed with heterothallic strains, also yields recombinant progeny and thus undergoes nuclear fusion and meiosis. Microdensitometric measurements of nuclear DNA content are reported which indicate thatCLamoebae are haploid like heterothallic amoebae, and crossed plasmodia are diploid. However, clonally formedCLplasmodia were found to have the same G2nuclear DNA content asCLamoebae. This observation excludes the possibility of nuclear fusion when plasmodia form within clones ofCLamoebae and therefore the strain cannot be homothallic. Two alternatives, apogamy and coalescence, are proposed as the most likely mechanisms for clonal plasmodium formation in strainCL.
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Abstract
1. The occurrence of fusion between plasmodia produced from amoebal clones of P. polycephalum was studied.2. The occurrence of fusion was found to be strain-dependent and the factors responsible segregated in the progeny of a cross.3. The segregations found in crosses between several strains led to the conclusion that four alleles (f1–f4) of one gene f were controlling fusion in these strains.4. Fusion occurs only between plasmodia carrying identical f alleles, except in one class of results.5. A model accommodating all the results, including the ‘exceptional’ class, is proposed. It requires that the action of the f factors is to inhibit fusion between dissimilar strains rather than to promote fusion between identical strains. Certain physiological deductions from this model are discussed.6. The locus (mt) determining mating type of the amoebae is not concerned in plasmodial fusion and is unlinked to f.7. The rate of fusion between some pairs of strains is apparently influenced by modifying genes.8. It is suggested that, as a result of the operation of the f gene and of the previously described killing reaction, heterokaryons will occur rarely in natural populations of P. polycephalum.
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Abstract
1. Improved methods for the culture and preservation ofPhysarum polycephalumamoebae have been developed.2. Strains of amoebae have been isolated which are stably resistant to 4, 8 or 16 μg./ml. actidione.3. Sensitivity vs. resistance to 4 μg./ml. actidione is probably controlled by a single pair of alleles at a locus unlinked to the mating-type locus.4. Plasmodia homozygous or heterozygous for the allele determining resistance at this locus are no more resistant to actidione than plasmodia homozygous for the allele determining sensitivity.
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