Showing papers by "University of Oviedo published in 1981"
TL;DR: An activity which releases p-nitroaniline from substrates having the structure X-prolyl-p-nitROanilide (X-Pro-pNA), which resembles the dipeptidyl peptidase IV widely distributed among human tissues and which is found both in a strain having all known proteases and also in a yeast mutant lacking protease A, protease B and carboxypeptidase Y.
47 citations
TL;DR: A highly sensitive and selective fluorimetric determination of potassium is proposed, based on solvent extraction of the ion-pair formed between a large anion and the cationic complex of K(+) with a crown ether, which gives a higher sensitivity than any similar method for potassium determination.
32 citations
TL;DR: Alkaline phosphatase from a purified fraction of vacuoles was characterized after gel filtration on Sephadex G-200 and 15 mU of enzyme activity was found, which may indicate that this enzyme is a metalloprotein.
Abstract: Candida utilis alkaline phosphatase has been detected in vacuoles. Liberation of the vacuoles was carried out by protoplast disruption under isotonic conditions. The polybase DEAE-dextran was used to induce damage to the yeast plasmalemma. The vacuoles were purified by centrifugation on sorbitol-Ficoll gradients. Alkaline phosphatase from a purified fraction of vacuoles was characterized after gel filtration on Sephadex G-200. We have found 15 mU of enzyme activity per 108 vacuoles. This enzyme activity elutes on Sephadex G-200 at a volume-to-void-volume ratio of 1.65. The approximate molecular weight is 1.35×105. TheKm value forp-nitrophenyl-phosphate is 2.5×10−3 M. The pH for maximum activity is 8.9, and the enzyme is stable at pH values between 7.0 and 9.0. Rapid inactivation occurs at temperatures above 45°C. The enzyme catalyzes the hydrolysis of phosphomonoester bonds of a wide variety of molecules, especially polyphosphates. Thus, vacuolar polyphosphates are probably the natural substrate of this enzyme. Orthophosphate, arsenate, ethylenediaminetetraacetate, molybdate, and borate act as inhibitors. Fluoride is not an inhibitor, and the activity is not affected byp-hydroxymercuribenzoate. Some metal ions also affect the activity of vacuolar alkaline phosphatase. This may indicate that this enzyme is a metalloprotein.
18 citations
TL;DR: The aminomercuration-demercuration of 1,4- and 1,5-hexadiene yield cis- and trans-2,5dimethyl-N-arylpyrrolidines via one-pot process as discussed by the authors.
13 citations
TL;DR: In this paper, un tratamiento matematico is presented, in which in la etapa inicial del trabajo se consideran conjuntos constituidos por resultados elementales, and en una segunda etapa se decide whether or not a conjunto is constituidado by pares de resultados.
Abstract: En este trabajo, se propone y estudia una medida para la incertidumbre correspondiente a las utilidades, o inquietud. Este concepto recibe por vez primera un tratamiento matematico. En la etapa inicial del trabajo se consideran conjuntos constituidos por resultados elementales, y en una segunda etapa se consideran conjuntos constituidos por pares de resultados.
10 citations
TL;DR: In this article, the authors investigated microfissures of thermal origin in granitic rock specimens, taken from the area of a heater test performed at the Stripa Test Site in Sweden.
Abstract: Microfissures of thermal origin were investigated in granitic rock specimens, taken from the area of a heater test performed at the Stripa Test Site in Sweden. Optical and electron microscope techniques were simultaneously applied to obtain a complete information of the rock microfractography related to the texture and mineralogy. This microfractography network was quantified by digital image processing. Original microphotographs were digitized by a flat microdensiometer. Then, segmentation, thinning and line-following algorithms were succesively applied for enhancing, detecting and measuring the microfissures. The described technique was applied to material subjected to one, slow in situ heating cycle reaching a maximum temperature of about 220°C and to non-heated material taken from the same area. No significant differences in the fissuration density were detected when comparing heated and non-heated material.
8 citations
TL;DR: A variety of effectors, including hormones and toxins, cause changes in transmembrane ion gradients and the possibility that these changes are an alternative for cyclic AMP as second messenger or an additional and independent form of transmitting information to the cell interior is discussed.
8 citations
TL;DR: It is found that cholera toxin does not need to activate adenylate cyclase to induce permeability changes in the cell membrane since the experiments were carried out in conditions where neither ATP nor cyclic AMP was present.
6 citations
TL;DR: In this article, the authors used a high-boiling point substancesolvent mixture as evaporation source, in order to make the temperature range of the experimental measurements wider and thus, measurements can be made at and above the normal boiling point temperature of the liquid solvent without pressure modifications.
Abstract: very high or very low vapor pressure, and that measurements cannot be madeabove the boiling temperature of the liquid phase23\ The former drawbackscan be overcomein many systems by using a high-boiling point substancesolvent mixture as evaporation source, in this way making the temperature range of the experimental measurements wider. Thus, measurements can be made at and above the normal boiling point temperature of the liquid solvent without pressure modifications.
5 citations
TL;DR: In this paper, a new type of mechanism in the oxidation of alkenes by mercury(II) salts is proposed, which cannot be explained by formation of an allylic mercurial.
5 citations
TL;DR: Methyl-alpha-D-galactoside was the most efficient inducer, giving a maximal differential rate of synthesis of the enzyme of 110 mU/10(7) cells at a concentration of 180 mM, and the concentration of inducer required to obtain half-maximal induction was similar for lactose, L-arabinose and isopropyl-beta- D-thiogalactosid and about 5-fold higher for methyl-alpha.
01 Jan 1981
TL;DR: Differences in the induction efficiency of ONPG-hydrolytic activity by lactose or galactose, which could have taxonomic implications, were observed among the species.
Abstract: β-Galactosidase activity in intact cells of 21 species ofStreptomyces was measured using ONPG hydrolysis, without addition of a permeabilizing agent. Differences in the induction efficiency of ONPG-hydrolytic activity by lactose or galactose, which could have taxonomic implications, were observed among the species.
01 Jan 1981
TL;DR: This paper argued that the only way to prove the presence of semantic intentions in children's linguistic expressions may be to compare our interpretations with the presumably real intentions of children, retaking then the inadequate expansions method.
Abstract: espanolEn este trabajo Francisco Valle cuestiona el enfoque de la literatura americana sobre el lenguaje de los ninos, en la que se considera el orden de las palabras como el medio estructural basico para transmitir significados y comunicar diferentes intenciones. Fundamenta sus criticas desde cuatro vertientes: datos provenientes de otras lenguas, algunas excepciones en ninos angloparlantes o anglodiscentes, resultados de estudios de aceptabilidad gramatical y la nueva orientacion de la linguistica y la psicologia del lenguaje, para las que el componente semantico se ha convertido en el nucleo mismo del lenguaje. El autor coincide con Howe en el peligro del adultomorfismo, sugiriendo que tal vez la unica manera de comprobar la presencia de intenciones semanticas en las expresiones linguisticas infantiles sea comparar nuestras interpretaciones con las supuestas intenciones reales de los ninos, retomando para ello el metodo de las expansiones inadecuadas. En la ultima parte se aclaran algunas confusiones cometidas por Bushnell y Aslin al aplicar este metodo y se explican las diferencias entre significado referencial y relacional, finalizando con un resumen de los puntos basicos que hay que tener en cuenta al hacer expansiones inadecuadas. EnglishIn this paper Francisco Valle disputes the American approach to the children�s language issue, which considers word order as the main structural way to communicate meanings and different intentions. He bases his critics on four aspects: data from other languages, some exceptions of English-speaking or �English-talking� children, results of grammatical acceptability studies and linguistics and language psychology�s new course, with the semantic component as the very nucleus of language. The author agrees with Howe that adultmorphism may be a danger and he suggests that the only way to prove the presence of semantic intentions in children�s linguistic expressions may be to compare our interpretations with the presumably real intentions of children, retaking then the inadequate expansions method. In the last part some of the mistakes made by Bushnell and Aslin in the method application are clarified and the differences between referential and relational meaning are explained. Finally the author offers a summary of the basic points to be taken into account to make inadequate expansions.