Showing papers by "University of Seville published in 1985"
TL;DR: The increase in salt concentration was correlated with increase in diurnal temperature and biomass present and with decrease in oxygen concentrations, and all organisms found at the lower salt concentrations disappeared, and instead large populations of halobacteria developed.
Abstract: A multi-pond saltern that creates a gradient of salt concentrations has been studied with respect to some characteristics of the resulting environments and their microbial populations. The increase in salt concentration was correlated with increase in diurnal temperature and biomass present and with decrease in oxygen concentrations. Many types of organisms below 15% (w/v) total salts, were found, many of them normal inhabitants of seawater and even freshwater. Most organisms over 15% salts were halophilic. The salt concentrations comprised two ranges, each characterized by different microbial populations. First, between 15 and 30% salts, the populations ofDunaliella increased, reaching large numbers; moderately halophilic eubacteria and some fast-growing halobacteria predominated as heterotrophic microorganisms and, among the first, thePseudomonas-Alteromonas-Alcaligenes group andVibrio were the more abundant taxonomic groups; and gram-positive cocci appeared mainly over 25% salts. Phototrophic bacteria, both oxygenic and anoxygenic, were also found in this range, and among the anoxygenic type,Chromatium species andRodospirillum salexigens were probably predominant. Second, over 30% salts the diversity decreased greatly, all organisms found at the lower salt concentrations disappeared, and instead large populations of halobacteria developed. Over 50% salts, only three species of halobacteria were found.
196 citations
TL;DR: The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate, fermentation rate or respiration rate of Saccharomyces cerevisiae wild type strain S288C.
Abstract: The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate (μ), fermentation rate (v) or respiration rate (ϱ) of Saccharomyces cerevisiae wild type strain S288C. Cells which have respiratory metabolism show K
i (ethanol inhibition constant) values for μ, v and ϱ, higher (K
i>1 M) than those of “petite” mutants or “grande” strains grown in anaerobiosis (K
i=0.7 M). In addition, the relationship between μ or v and ethanol concentration is linear in cells with respiratory metabolism and exponential in cells lacking respiration. When functional mitochondria are transferred to “petite” mutants, the resulting strain shows K
i values similar to those of the “grande” strain and the inhibition of μ and v by increasing ethanol concentrations becomes linear.
60 citations
TL;DR: The changes in the activity of the pentose phosphate cycle produced by the activation or inhibition of different NADPH-consuming pathways have been studied and the regulation of the apex phosphate cycle mainly by the intracellular NADPH/NADP ratio is discussed.
57 citations
TL;DR: The proton electrochemical gradient has been measured in old brain mitochondria isolated from 2- or 24-month-old rats with the use of different respiratory substrates, indicating that the dielectric strength of the mitochondrial membrane was unaltered in old animals.
49 citations
TL;DR: Glutamine synthetase from the unicellular cynabacterium Anacystis nidulans was found associated with the membrane fraction of cell-free extracts and acted as an inhibitor of both activities (transferase and biosynthetic) of glutamine Synthetase in vitro.
43 citations
TL;DR: It is concluded that GABA and GABA-agonists (DAVA and VPA) may induce hypothermia partly mediated by activation of bicuculline-insensitive GABA-receptors.
Abstract: 1. 1.|GABA, δ-aminovaleric acid (DAVA) and sodium valproate (VPA) decrease core temperature in conscious rats. 2. 2.|Bicuculline increases GABA-induced hypothermia, does not modify DAVA (250 mg/kg) and VPA (100 and 400 mg/kg) hypothermia and antagonizes initial hypothermia by DAVA (1000 mg/kg) and VPA (200 mg/kg) and late hypothermia by DAVA (500 mg/kg) and VPA (200 mg/kg). 3. 3.|Picrotoxin increases late hypothermia by GABA (250 mg/kg) and VPA (400 mg/kg), but decreases initial hypothermia by VPA (200 mg/kg). 4. 4.|Pentylenetetrazol increases variably GABA-induced hypothermia, inhibits early hypothermia by DAVA and increases hypothermia induced by VPA (400 mg/kg). 5. 5.|We conclude that GABA and GABA-agonists (DAVA and VPA) may induce hypothermia partly mediated by activation of bicuculline-insensitive GABA-receptors.
41 citations
31 citations
TL;DR: The results of a study of the properties of both negative-and positive-parity states in odd-proton Cs and odd-neutron Xe isotopes within the framework of the Proton-Neutron interacting boson-fermion model (IBFA-2) were presented in this article.
31 citations
TL;DR: An elementary non-linear control system with an adaptive mechanism that shows a strange attractor is analysed and power spectra of the system confirm the existence of chaotic motion.
Abstract: An elementary non-linear control system with an adaptive mechanism that shows a strange attractor is analysed in this paper The chaotic behaviour is due to a reinjection phenomenon associated with the folded characteristic of the non-linear element Power spectra of the system confirm the existence of chaotic motion
31 citations
TL;DR: Current flowing through single Ca- and voltage-activated K channels has been recorded from cell-attached and inside-out excised membrane patches of cultured Y-1 adrenocortical cells and it is possible that these K channels modulate Ca influx across the plasma membrane and thus contribute to regulate steroid biosynthesis and release.
25 citations
TL;DR: In this paper, the uniqueness of an optimal solution in general continuous single facility minisum and minimax location problems was studied and the concept of an S-norm was defined.
DOI•
01 Jun 1985TL;DR: A simple recurrence formula to obtain the Green's function for multilayered anisotropic structures, with rectangular boundary conditions involving electric and magnetic walls and open boundaries, is presented.
Abstract: In the paper, a simple recurrence formula to obtain the Green's function for multilayered anisotropic structures, with rectangular boundary conditions involving electric and magnetic walls and open boundaries, allows us to present an unified variational approach in the spectral domain to find both upper and lower bounds on the mode capacitances of a large class of planar transmission structures Very accurate results are obtained by using appropriate trial functions to approximate the surface charge density on the strips and the interface potential distribution for several significant MIC configurations
TL;DR: Ferredoxin from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity by an easy and fast procedure with a high yield (25 -30 mg/250 g wet weight of cells) and an average molecular weight of 11800 was calculated from sedimentation coefficient, Stokes radius, and amino acid composition.
Abstract: Abstract Ferredoxin from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity by an easy and fast procedure with a high yield (25 -30 mg/250 g wet weight of cells). An average molecular weight of 11800 was calculated from sedimentation coefficient (1.70 S) and Stokes radius (1.75 nm) data, sodium dodecyl sulfate-electrophoresis, and amino acid composition. Absorption spectrum show ed maxima at 276, 330, 420 and 460 nm in the oxidized form, with an absorption ratio (A420/A276) of 0.54 and an extinction coefficient of 8.38 mᴍ-1· cm -1 at 420 nm. R educed ferredoxin show ed a single peak at 276 nm with shoulders at 284, 310, 390, 469 and 537 nm and at liquid helium temperatures gave EPR signals at g = 1.877, 1.951 and 2.045. The protein has an isoelectric point of 3.30, and one (2Fe-2S)-cluster per molecule with a midpoint potential, at pH 7.5, of -410 mV (n=1) . The m olecule of C. reinhardii ferredoxin consists of 95-99 amino acid residues which includes the full com plement of amino acids, being alanine the most abundant.
TL;DR: It is clear that the surface migration of protons plays an important role during the dehydration process and the influence on the degree of surface hydration, the dehydration rate, and the numbers of certain ionic groups on the surface exerted by the temperature rate in a linear heating program and by initial surface coverage.
Abstract: A comparative study of the dehydration of the (001) and (111) surfaces of ${\mathrm{TiO}}_{2}$ (anatase) has been made starting from a master equation and introducing suitable transition probabilities. From the experimental data considered, relative to sample ``Degussa P25'' of Munuera and co-workers, it is concluded that the (111) face is the most likely to be exposed. The detailed mechanism of dehydration is analyzed and an estimate of the values of activation energies and frequency factors is presented. This analysis makes it clear that the surface migration of protons plays an important role during the dehydration process. Also the influence on the degree of surface hydration, the dehydration rate, and the numbers of certain ionic groups on the surface exerted by the temperature rate in a linear heating program and by initial surface coverage are discussed.
TL;DR: In this paper, the synthesis and conformational analysis of 2-fluoro, 2-hydroxy and 2-methoxy thioderivatives (thioethers, sulphoxides, sulphones and sulphonium salts) are reported.
TL;DR: In this paper, the accuracies of the approximation of the temperature integral of the Arrhenius law proposed by Coats and Redfern(CR), Doyle(D), Gyulai and Greenhow(GG), and MacCallum and Tanner(McT) have been tested.
Abstract: The accuracies of the approximation of the temperature integral of the Arrhenius law proposed by Coats and Redfern(CR), Doyle(D), Gyulai and Greenhow(GG), and MacCallum and Tanner(McT) have been tested. It has been demonstrated that these methods (only with the exception of the MacCallum and Tanner procedure) generally lead to accurate enough values of the activation energy of solid state reactions.
The accuracy of these methods increases in the sequence: CC > D ≃ GG ≫ McT.
TL;DR: The electrophysiological properties of septal neurons have been examined in vitro in guinea pig brain slices and stimulation of the fimbria evoked postsynaptic responses consisting of either adepolarization, a hyperpolarization or a depolarization-hyperpolarized sequence.
TL;DR: The binding of vasoactive intestinal peptide and stimulation of adenylate cyclase were studied in bovine thyroid plasma membranes and suggested the presence of two classes of binding sites: a class with high affinity and low capacity and one with low affinity and high capacity.
TL;DR: The biological analysis of several populations confirms the existence in the Iberian Peninsula of two species of Muscari subgenus Leopoldia : M. comosum and M. matritensis (the latter described as new), which differ in at least a translocation rearrangement.
TL;DR: The synthesis and analytical properties of two asymmetric derivatives of carbohydrazide and thiocarbohydrazide with pyridine and phenol and the analytical utility of these reagents are outlined.
TL;DR: A 44-year-old man with no family history of keratosis punctata showed, at the age of 19 years, punctiform hyperkeratotic elements confined exclusively to the flexion creases of the palms and digits.
Abstract: A 44-year-old man with no family history of keratosis punctata showed, at the age of 19 years, punctiform hyperkeratotic elements confined exclusively to the flexion creases of the palms and digits. We review the literature and comment on the clinical, histologic, and therapeutic aspects of this exceptional dermatosis.
TL;DR: Culture conditions, plating density, and ventilation govern the production of fruiting bodies in Phycomyces, both regular sporangiophores (macrophores) and dwarf ones (microphores), and microphorogenesis is stimulated by increased carbon dioxide concentrations, but is largely unaffected by variations in oxygen content of the atmosphere.
TL;DR: In this paper, the influence of pressure and temperature on Sm2O3 hydration, under mild conditions, was examined, and it was shown that the presence of CO2 can significantly increase the temperature of H2O decomposition.
Abstract: The influence of pressure and temperature on Sm2O3 hydration, under mild conditions, are examined. The data and conclusions are referred to previous ones for Yb2O3.
At the activation temperatures usually applied, as reported in the literature, to rare earth sesquioxides handled in air, 800–850 K, a non-pure-oxide phase is attained in the case of Sm2O3. Its complete dehydration is achieved at 823 K, but temperature programmed decomposition and Fourier transform-IR data lend support to the formation at this temperature of a dioxymonocarbonate phase which is transformed into the sesquioxide phase above 1100 K.
Contrary to the finding for Yb2O3, hydration in bulk Sm2O3 has been observed over the whole pressure range 133–2666 Pa. In the absence of CO2, the temperature of evolution of H2O from bulk-hydrated Sm2O3, about 600 K, is considerably higher than that previously reported for Yb2O3, 440 K, following the cation polarizing pattern for the decomposition of metal hydroxides and oxosalts.
TL;DR: In this article, the influence of the precursor salt on the surface behavior of some Lu2O3 samples has been studied by means of TG, DTA, X-ray diffraction, SEM, SBET measurements and FT-IR spectroscopy.
Abstract: The influence of the precursor salt on the surface behaviour of some Lu2O3 samples has been studied. They have been prepared by thermal decomposition of lutetium oxalate, basic carbonate, and hydroxide, and studied by means of TG, DTA, X-ray diffraction, SEM, SBET measurements and FT-IR spectroscopy. The surface reactivity of Lu2O3 samples obtained via hydroxide and carbonate is greater than that observed for the oxide obtained via the oxalate, as studied by the influence of thermal treatments on their hydration capacities and on their specific surface areas. The differences between the crystalline structures of the precursor salt and the final oxide satisfactorily accounted for the different surface behaviours of the oxides studied.
TL;DR: The pKa values for the indole ring protonation equilibria of the Rauwolfia alkaloids, yohimbine, ajmalicine, reserpine and reserpiline have been measured in strongly sulfuric acid solutions as discussed by the authors.
TL;DR: In this article, the influence of the preparation method on the hydration process is examined, by extending the study to two additional samples, a standard commercial one and another obtained by calcining a ytterbium oxalate.
Abstract: Preliminary studies have shown that in order to achieve the complete removal of the uptaken CO2 and H2O from a ytterbium oxide aged in air, thermal activation up to 1173 K is required. Parallel studies have shown that bulk hydration of Yb2O3 does occur, the CO2 acting as a kinetic inhibitor. The above results refer to a Yb2O3 prepared in our laboratory from hydroxicarbonate-like phases. In the present work, the influence of the preparation method on the hydration process is examined, by extending the study to two additional samples, a standard commercial one and another obtained by calcining a ytterbium oxalate. It is shown that the intensity of the hydration reaction depends strongly on the method of preparation. Certain applications of 4f oxides, such as their use as transition metal supports, involve thermochemical processes which may alter drastically the initial texture of the ytterbia from the oxalate. It makes this sample less useful although its initial specific surface area is high.
TL;DR: Fructose 2,6‐bisphosphate may be involved in the control of insulin‐induced glycolysis, but it does not seem to play a role in the stimulation of glucolytic by adrenaline.
TL;DR: In this article, the nuclear structure information obtained from measurements of charge radii in even-even and even-odd nuclei terms of the interacting boson model was analyzed and the observed deviations from the smooth behavior, R = R 0 A 1 3, appear to be well described by this model.
TL;DR: A method of hybrid selection between homothallic wild-type and heterothallic strains was developed to study the heredity of ethanol tolerance and production, but no ethanol-sensitive strains were able to produce high levels of ethanol.
Abstract: We developed a method of hybrid selection between homothallic wild-type and heterothallic strains. The hybrids obtained were used to study the heredity of ethanol tolerance and production. Both characters segregated independently, but no ethanol-sensitive strains were able to produce high levels of ethanol. At least four genes are implicated in ethanol tolerance.
TL;DR: It is concluded that the light-dependent ADH decrease is not mediated by themad photosystem, as two strains carry multiple mutations and show extremely reduced phototropism even at light intensities higher than the light intensity used in this work.