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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 139 (1994), S. 97-102 
    ISSN: 1432-1424
    Keywords: l-glutamic uptake ; Acidic amino acids ; System X AG − ; Red blood cells ; Frog Rana esculenta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Evidence is presented that the high levels of internal l-glutamic and l-aspartic acid in frog Rana esculenta red blood cells are due to the existence of a specific carrier for acidic amino acids of high affinity K m = 3 μm and low capacity (Vmax) 0.4 μmol l-Glu · Kg−1 dry cell mass · 10 min−1. It is Na+ dependent and the incorporation of l-glutamic acid can be inhibited by l and d-aspartate and l-cysteic acid, while d-glutamic does not inhibit. Moreover, this glutamic uptake shows a bell-shaped dependence on the external pH. All these properties show that this carrier belongs to the system X AG − family. Besides the incorporation through this system, l-glutamic acid is also taken up through the ASC system, although, under physiological conditions, this transport is far less important, since it has relatively low affinity K m 39 μm but high capacity (V max) 1.8 μmol l-Glu · Kg−1 dry cell mass · 10 min−1.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1424
    Keywords: Alanine uptake ; Red blood cells ; Peripheral blood lymphocytes ; Isolated hepatocytes ; asc System ; Trout (Salmo trutta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The Na+-independent uptake of l-alanine has been studied in trout red blood cells, isolated hepatocytes and peripheral blood lymphocytes. The present study shows the existence of two functionally different Na+-independent systems for short chain neutral amino acids in these cells. They are designated as asc systems because of their resemblance to systems described in other cell types. Besides their independence of sodium and a rough similarity in substrate preference, the most important property shared by the two carriers is a lack of trans-stimulation, allowing further differentiation from system L. One of them is an unusually stereospecific carrier present in red blood cells, the other is less restrictive and present in hepatocytes and peripheral blood lymphocytes. Extracellular acid pH increases the incorporation to red blood cells, while it slightly depresses the uptake in the other cells. From the data presented, it is not possible, at first, to classify these carriers as asc 1 or asc 2 systems. Moreover, the system present in red cells resembles that found in the nonerythroid cells, BSC-1, while there is no clear parallelism between the system found in hepatocytes/lymphocytes and any of those described previously.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 134 (1993), S. 251-259 
    ISSN: 1432-1424
    Keywords: Glycine uptake ; Trout (Salmo truttd) ; Red blood cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The present study demonstrates the presence of different amino acid carriers in the membrane of trout red cells. Most glycine is taken up through the Na+-dependent system ASC, although the nearly specific Gly system is also active. Besides these carriers, glycine is taken up by means of Na+-independent transporters, system l being the most important. A system asc of high affinity and low capacity has been found, and band 3 is unable to transport glycine under physiological conditions. These results suggest that although all these carriers are already present in primitive vertebrates, several differences exist in their properties with respect to those found in mammalian cells. We would like to express our sincere thanks to Mr. Antonino Clemente (Piscifactoria de Bagà, Medi Natural, Generalitat de Catalunya) for his help and logistical assistance and to Mr. Robin Rycroft for his editorial help.
    Type of Medium: Electronic Resource
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  • 4
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    Unknown
    Madrid : Periodicals Archive Online (PAO)
    Revista de literatura. 53:105/106 (1991:enero/dic.) 175-177 
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  • 5
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    Unknown
    Madrid : Periodicals Archive Online (PAO)
    Revista de literatura. 55:109/110 (1993:enero/dic.) 267-271 
    ISSN: 0034-849X
    Topics: Linguistics and Literary Studies
    Notes: RESEÑAS DE LIBROS
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 346 (1993), S. 269-274 
    ISSN: 1434-601X
    Keywords: 21.60.-n ; 25.70.Hi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study pairing correlations in deformed nuclei in the framework of the Nilsson+BCS theory. As in the spherical case, the pairing interaction is found to induce strong spacial correlations between the partners of each paired couple. The presence of the deformed mean field gives rise to a non-spherical pair field, whose deformation is governed by the properties of a few single-particle orbitals around the Fermi surface and does not necessarily follow the shape of the mean field. Multipole expansion of the pair field yields all the pair densities associated with the direct two-particle transfer processes to the members of the g.s. rotational band in the A+2 system. The interplay of the deformations of the mean and the pair fields can lead to different relative magnitudes and phases of these densities and therefore to different excitation patterns of the rotational bands in two-particle transfer reactions. In the case of non-collective twoquasiparticles and bands the associated pair densities display large components with high multipoles and the associated transfer processes may be favoured in heavy-ion collisions by kinematical conditions. Examples corresponding to both prolate and oblate cases are considered.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 153 (1993), S. 287-293 
    ISSN: 1573-5036
    Keywords: grain protein concentration ; grain yield ; nitrogen ; tritordeum ; triticale ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The new species of cereal × Tritordeum Ascherson et Graebner (Hordeum chilense Roem. et Shultz × Triticum ssp.) has a grain protein concentration (GPC) of up to 25%. The relationship between GPC and yield, and the factors responsible for the high GPC of tritordeum were examined and compared in field experiments. Three experimental tritordeum lines, two early and a later released (recombined and secondary tritordeums) were compared to wheat (cv. Cajeme) and triticale cultivars (cv. Trujillo). GPC's were 19%–22% for recombined tritordeums, 16% for the secondary tritordeum, 12–15% for wheats and 11% for triticale. Grain yields of the recombined and secondary tridordeum were 17–33% and 45–57% that of the wheats and triticale, respectively. Reducing grain sink size by spikelet removal resulted in an increased GPC of remaining grains. Considering all species together there were a strong inverse relationship between GPC and grain yield (GY) per main ear (GPC=26−4.76 ln GY; r2=0.82). In another experiment, frost damage to an early sown treatment of wheat reduced sink size. Harvest index (HI) of early sown wheat was reduced from 0.45 to 0.19, values comparable to that of tritordeum. Having similar HI, the GPC of the early sown wheat was the same as an early sown tritordeum (around 18%). Data for total N uptake and the N concentration of plant tissue during the growing season indicated that enhanced N uptake and remobilisation were not responsible for tritordeum's high GPC. These results suggest that the high GPC of the early lines of tritordeum is a consequence of the small grain yield concentrating the grain protein.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 162 (1992), S. 448-454 
    ISSN: 1432-136X
    Keywords: Glucose metabolism ; Anaerobiosis ; Isoproterenol ; Catecholamines ; Trout, Salmo trutta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Glucose metabolism has been studied in Salmo trutta red blood cells. From non-metabolizable analogue (3-O-methyl glucose and l-glucose) uptake experiments it is concluded that there is no counterpart to the membrane transport system for glucose found in mammalian red blood cells. Once within the cells, glucose is directed to CO2 and lactate formation through both the Embden-Meyerhoff and hexose monophosphate shunts; lactate appears as the most important endproduct of glucose metabolism in these cells. From experiments under anaerobic conditions, and in the presence of an inhibitor of pyruvate transfer to mitochondria, most of the CO2 formed appears to derive from the hexose monophosphate pathway. Appreciable O2 consumption has been detected, but there is no clear relationship between this and substrate metabolism. Key enzymes of glucose metabolism hexokinase, fructose-6-phosphate kinase and, probably, pyruvate kinase are out of equilibrium, confirming their regulatory activity in Salmo trutta red blood cells. The presence of isoproterenol, a catecholamine analogue, induces important changes in glucose metabolism under both aerobic and anaerobic conditions, and increases the production of both CO2 and lactate. From the data presented, glucose appears to be the major fuel for Salmo trutta red blood cells, showing a slightly different pattern of glucose metabolism from rainbow trout red blood cells.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 30 (1994), S. 261-264 
    ISSN: 1434-6079
    Keywords: 32.30.Jc ; 52.80.Yr ; 31.20.Tz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The spectrum of four times ionized Xenon (XeV), has been observed in the 500–6800 Å range and 84 new lines have been identified as transitions between levels of 5s5p 3, 5s 25p5d, 5s 25p6s, 5s 25p 2, and 5s 25p6p configurations. Nine new levels belonging to the configuration 5p6p have been determined. The results of this analysis are supported by Hartree-Fock calculations. The configurations are interpreted by fitting the theoretical energy parameters to the observed levels using least-squares techniques.
    Type of Medium: Electronic Resource
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