Search Results - (Author, Cooperation:G. Rivas)

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  1. 1
    H. ter Steege ; N. C. Pitman ; D. Sabatier ; C. Baraloto ; R. P. Salomao ; J. E. Guevara ; O. L. Phillips ; C. V. Castilho ; W. E. Magnusson ; J. F. Molino ; A. Monteagudo ; P. Nunez Vargas ; J. C. Montero ; T. R. Feldpausch ; E. N. Coronado ; T. J. Killeen ; B. Mostacedo ; R. Vasquez ; R. L. Assis ; J. Terborgh ; F. Wittmann ; A. Andrade ; W. F. Laurance ; S. G. Laurance ; B. S. Marimon ; B. H. Marimon, Jr. ; I. C. Guimaraes Vieira ; I. L. Amaral ; R. Brienen ; H. Castellanos ; D. Cardenas Lopez ; J. F. Duivenvoorden ; H. F. Mogollon ; F. D. Matos ; N. Davila ; R. Garcia-Villacorta ; P. R. Stevenson Diaz ; F. Costa ; T. Emilio ; C. Levis ; J. Schietti ; P. Souza ; A. Alonso ; F. Dallmeier ; A. J. Montoya ; M. T. Fernandez Piedade ; A. Araujo-Murakami ; L. Arroyo ; R. Gribel ; P. V. Fine ; C. A. Peres ; M. Toledo ; C. G. Aymard ; T. R. Baker ; C. Ceron ; J. Engel ; T. W. Henkel ; P. Maas ; P. Petronelli ; J. Stropp ; C. E. Zartman ; D. Daly ; D. Neill ; M. Silveira ; M. R. Paredes ; J. Chave ; A. Lima Filho Dde ; P. M. Jorgensen ; A. Fuentes ; J. Schongart ; F. Cornejo Valverde ; A. Di Fiore ; E. M. Jimenez ; M. C. Penuela Mora ; J. F. Phillips ; G. Rivas ; T. R. van Andel ; P. von Hildebrand ; B. Hoffman ; E. L. Zent ; Y. Malhi ; A. Prieto ; A. Rudas ; A. R. Ruschell ; N. Silva ; V. Vos ; S. Zent ; A. A. Oliveira ; A. C. Schutz ; T. Gonzales ; M. Trindade Nascimento ; H. Ramirez-Angulo ; R. Sierra ; M. Tirado ; M. N. Umana Medina ; G. van der Heijden ; C. I. Vela ; E. Vilanova Torre ; C. Vriesendorp ; O. Wang ; K. R. Young ; C. Baider ; H. Balslev ; C. Ferreira ; I. Mesones ; A. Torres-Lezama ; L. E. Urrego Giraldo ; R. Zagt ; M. N. Alexiades ; L. Hernandez ; I. Huamantupa-Chuquimaco ; W. Milliken ; W. Palacios Cuenca ; D. Pauletto ; E. Valderrama Sandoval ; L. Valenzuela Gamarra ; K. G. Dexter ; K. Feeley ; G. Lopez-Gonzalez ; M. R. Silman
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-10-19
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    *Biodiversity ; Models, Biological ; Population ; *Rivers ; South America ; Trees/*classification/*physiology
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Darawshe, S. ; Rivas, G. ; Minton, A.P.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0003-2697
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1006/abio.1993.1581

    Articles: DFG German National Licenses
  3. 3
    Darawshe, S. ; Rivas, G. ; Minton, A.P.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0003-2697
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1006/abio.1993.1092

    Articles: DFG German National Licenses
  4. 4
    Staff View
    ISSN:
    0014-5793
    Keywords:
    Equilibrium sedimentation ; Fibrinogen binding site ; GPIIb/IIIa ; Peptide synthesis ; Platelet ; Platelet aggregation
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0014-5793(93)80454-3

    Articles: DFG German National Licenses
  5. 5
    Rivas, G. ; Minton, A.P.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0968-0004
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0968-0004(93)90035-L

    Articles: DFG German National Licenses
  6. 6
    Rivas, G. ; Solis, V.M.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0302-4598
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0302-4598(92)80050-Q

    Articles: DFG German National Licenses
  7. 7
    Staff View
    ISSN:
    1432-1017
    Keywords:
    GPIIb, GPIIIa, and GPIIb/IIIa heterodimer ; Platelet fibrinogen receptor ; Molecular mass, size, shape and self-association
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Physics
    Notes:
    Abstract Human platelet plasma membrane glycoproteins IIb (GPIIb) and IIIa (GPIIIa) form a Ca2+-dependent heterodimer, the integrin GPIIb/IIIa, which serves as the receptor for fibrinogen and other adhesive proteins at the surface of activated platelets. Below the critical micellar concentration of Triton X100 (TtX), the three glycoproteins do not bind appreciably to TtX and form association products of large size. The size-exclusion chromatographic patterns of GPIIb, GPIIIa and GPIIb/IIIa have been obtained at 0.2% TtX, and the molecular properties of the association products and monomer fractions have been determined by analysis of the detergent bound to the glycoproteins, laser-light scattering, sedimentation velocity, and electron microscopy (TEM). The monomer of the GPIIb-TtX complex was identified by the molecular mass (M) of the glycoprotein moiety (125 ± 15 kDa), the molecular size (9.5 ± 1.5 nm × 11 ±1.5 nm) and globular shape observed by TEM. It has a molecular mass (M *) of 197 ± 20 kDa, a sedimentation coefficient inf20 supo* of 5.8±0.1 S, a Stokes radius R infs sup* of 6.8±0.4 nm, and a frictional ratio f */ infmin sup* of 1.7±0.14. The (GPIIb) n -TtX complexes are disulphide-bonded size-heterogeneous association products of GPIIb, tetramers being the smallest species found. GPIIIa has a greater propensity to self-associate than GPIIb, this tendency being lower below 1 mg GPIIIa/ml, 0.1 mM Ca2+, pH 9.0. The (GPIIIa) n -TtX complexes are noncovalent size-heterogeneous association products of GPIIIa, tetramers being the smallest form observed. The monomer of the GPIIIa-TtX complex was identified by the 103 ±15 kDa M determined for the glycoprotein moiety, and the 9 ± 1.5 nm × 10 ± 1.5 nm size and globular shape observed by TEM. It has a M * of 136 ± 15 kDa, a s inf20 supo* of 3.9 ± 0.3 S, a R infs /p* of 6.4 ± 0.5 nm, a f */f infmin sup* of 1.9 ± 0.3, and, when stored at pH 7.4, has a certain tendency to form filamentous association products (20–70 nm × 2–5 nm), as observed by TEM. The GPIIb/IIIa-TtX complex in 0.2% TtX/0.1 mM Ca2+ elutes as a single monomeric fraction, as deduced from the 210 ± 15 kDa M determined for its glycoprotein moiety and the 12 ± 1.5 nm × 14 ± 1.5 nm size of the globular forms observed by TEM. The GPIIb/IIIa-TtX complex has a M * of 315±20kDa, a s inf20 sup* of 8.9±0.2 S, a infs sup* of 7.4±0.2 nm, a f */f infmin sup* of 1.5±0.12, and appears in the electron micrographs in multiple forms (filled globular, empty oval, head-two-tails, and bilobular shapes), which on lowering the TtX concentration tend to self-associate, forming a bundant rosettes below the TtX critical micellar concentration.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00183324

    Articles: DFG German National Licenses
  8. 8
    Rivas, G. A. ; Usobiaga, P. ; González-Rodríguez, J.
    Springer
    Published 1991
    Staff View
    ISSN:
    1432-1017
    Keywords:
    Integrin GPIIb/IIIa ; Platelet fibrinogen receptor ; Ca2+-and temperature-regulation ; Analytical ultracentrifugation
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Physics
    Notes:
    Abstract The human platelet integrin GPIIb/IIIa (228 kDa), a Ca-dependent heterodimer formed by the αIIb subunit (GPIIb, 136 kDa) and the β3 subunit (GPIIIa, 92 kDa), serves as the fibrinogen receptor at the surface of activated platelets. The degree of dissociation of the GPIIb/IIIa heterodimer (s°20 *, 8.9 S) into its constituent glycoproteins (GPIIb, 5.8 S; and GPIIIa, 3.9 S) has been assessed by analytical ultracentrifugation in Triton X100 buffers, and its Ca2+- and temperature-dependence correlated with Ca2+-binding to GPIIb/IIIa and its temperature dependence. At 21°C half-maximal dissociation of GPIIb/IIIa occurs at 5.5 ± 2.5 × 10−8 M Ca2+, very close to the dissociation constant of the high affinity Ca-binding site of GPIIb/IIIa (Kd1 8 ± 3 × 10−8 M) (Rivas and González-Rodríguez, 1991) and much lower than the Kd of the 3.4 medium affinity Ca-binding sites (Kd2 4 ± 1.5 × 10−5 M), which seems to demonstrate that the stability of the heterodimer in solution at room temperature is regulated by the degree of saturation of the high-affinity Ca-binding site. At 4°C, the stability of the heterodimer is apparently Ca2+-independent, while at room and physiological temperatures (15–37°C) the degree of dissociation of the heterodimer is regulated by the degree of dissociation of the high- and medium-affinity Ca-binding sites, respectively. On increasing the Ca2+ concentration up to 1 × 10−4 M after dissociation in Triton X100 solutions, the reconstitution of the GPIIb/IIIa heterodimer depends on the time and temperature at which the dissociated heterodimer was maintained, being almost complete within the first 5–10 min at 37°C and within the first 1–2 h at 21°C. After this time, a time- and temperature-dependent irreversible autoassociation of GPIIb (covalent) and GPIIIa (non-covalent) occurs, which hinders both the isolation of permanently stable monoamers of GPIIb and GPIIIa and the reconstitution of the GPIIb/IIIa heterodimer in Triton X100 solutions.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00450564

    Articles: DFG German National Licenses