782 resultados para EC 2
Resumo:
Agents that damage DNA in Escherichia coli or interfere with its replication induce DNA repair and mutagenesis via the SOS response. This well-known activity is regulated by the RecA protein and the LexA repressor. Following repair or bypass of the DNA lesion, the cell returns to its resting state by a largely unknown process. We found that 2-keto-4-hydroxyglutarate aldolase (4-hydroxy-2-oxoglutarate aldolase; EC 4.1.3.16) is necessary for the recovery of respiration and that it is regulated by the SOS response. This protein was induced by DNA-damaging agents. Induction required RecA activation. When the LexA regulon was repressed, activation of RecA was not sufficient for induction, indicating the requirement for an additional protein under LexA control. Finally, a mutant in the corresponding hga gene was UV sensitive. 2-Keto-4-hydroxyglutarate aldolase also plays a role in respiratory metabolic pathways, which suggests a mechanism for respiration resumption during the termination of the SOS response.
Resumo:
Using data derived from peptide sequencing of p68/70, a protein doublet induced during optic nerve regeneration in goldfish, we have isolated cDNAs that encode RICH (regeneration-induced CNPase homolog) from a goldfish regenerating retina cDNA library. The predicted RICH protein comprises 411 amino acids, possesses a pI of 4.48, and shows significant homology to the mammalian myelin marker enzyme 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase; EC 3.1.4.37). The mRNA encoding RICH was demonstrated, by both Northern blot analysis and RNase protection assays, to be induced as much as 8-fold in regenerating goldfish retinas at 20 days after nerve crush. Analysis of total RNA samples from various tissues showed a broad distribution of RICH mRNA, with the highest levels observed in gravid ovary. The data obtained strongly suggest that RICH is identical or very similar to p68/70. The molecular cloning of RICH provides the means for a more detailed analysis of its function in nerve regeneration. Additionally, the homology of RICH and CNPase suggests that further investigation may provide additional insight into the role of these proteins in the nervous system.
Resumo:
Prolyl 4-hydroxylase (EC 1.14.11.2) catalyzes the posttranslational formation of 4-hydroxyproline in collagens. The vertebrate enzyme is an alpha 2 beta 2 tetramer, the beta subunit of which is a highly unusual multifunctional polypeptide, being identical to protein disulfide-isomerase (EC 5.3.4.1). We report here the cloning of a second mouse alpha subunit isoform, termed the alpha (II) subunit. This polypeptide consists of 518 aa and a signal peptide of 19 aa. The processed polypeptide is one residue longer than the mouse alpha (I) subunit (the previously known type), the cloning of which is also reported here. The overall amino acid sequence identity between the mouse alpha (II) and alpha (I) subunits is 63%. The mRNA for the alpha (II) subunit was found to be expressed in a variety of mouse tissues. When the alpha (II) subunit was expressed together with the human protein disulfide-isomerase/beta subunit in insect cells by baculovirus vectors, an active prolyl 4-hydroxylase was formed, and this protein appeared to be an alpha (II) 2 beta 2 tetramer. The activity of this enzyme was very similar to that of the human alpha (I) 2 beta 2 tetramer, and most of its catalytic properties were also highly similar, but it differed distinctly from the latter in that it was inhibited by poly(L-proline) only at very high concentrations. This property may explain why the type II enzyme was not recognized earlier, as an early step in the standard purification procedure for prolyl 4-hydroxylase is affinity chromatography on a poly(L-proline) column.
Resumo:
With x-ray absorption spectroscopy and polarized neutron reflectometry we studied how the magnetic proximity effect at the interface between the cuprate high-TC superconductor YBa_(2)Cu_(3)O_(7) (YBCO) and the ferromagnet La_(2/3)Ca_(1/3)MnO_(3) (LCMO) is related to the electronic and magnetic properties of the LCMO layers. In particular, we explored how the magnitude of the ferromagnetic Cu moment on the YBCO side depends on the strength of the antiferromagnetic (AF) exchange coupling with the Mn moment on the LCMO side. We found that the Cu moment remains sizable if the AF coupling with the Mn moments is strongly reduced or even entirely suppressed. The ferromagnetic order of the Cu moments thus seems to be intrinsic to the interfacial CuO_(2) planes and related to a weakly ferromagnetic intraplanar exchange interaction. The latter is discussed in terms of the partial occupation of the Cu 3d_(3z^(2)−r^(2)) orbitals, which occurs in the context of the so-called orbital reconstruction of the interfacial Cu ions.
Resumo:
Las prácticas clínicas de Enfermería, son un elemento fundamental para el proceso de enseñanza – aprendizaje de los estudiantes de Grado en Enfermería. En estos entornos, los estudiantes toman contacto con su futura profesión aplicando los conocimientos teóricos y desarrollando habilidades para la prestación de cuidados a los pacientes. En este trabajo de investigación acción, se describen y aportan resultados de las dos etapas determinadas en este estudio piloto. En primer lugar, se estudia y analiza la opinión de una muestra accidental de estudiantes del grado en Enfermería sobre la organización y distribución de puestos de prácticas en este momento, empleando como instrumento un cuestionario de 15 ítems. Posteriormente y tras el análisis de los datos obtenidos en la fase previa, se decide diseñar y aplicar un instrumento basado en la Web 2.0 y se formula un protocolo en el que la elección de las unidades de prácticas las realiza la estudiante o el estudiante, siguiendo los pasos establecidos.
Resumo:
El presente informe científico-técnico tiene como objetivo el presentar, sintetizar y analizar los aspectos más relevantes de las presentaciones orales presentadas en la Mesa de Comunicaciones número 2, de las XIII Jornadas de Redes de Investigación en Docencia Universitaria de la Universidad de Alicante (edición 2014-2015). Las contribuciones presentadas han sido realizadas por docentes de la Universidad de Castilla-La Mancha, la Universidad Católica de Murcia y la Universidad de Alicante. Asimismo, se presentan los temas de interés debatidos entre ponentes y asistentes en la fase final del encuentro.
Resumo:
Enantiomerically pure carbamate-monoprotected trans-cyclohexane-1,2-diamines are used as chiral organocatalysts for the addition of aryl ketones and acetone to nitroalkenes to give enantioenriched β-substituted γ-nitroketones. The reaction was performed in the presence of 3,4-dimethoxybenzoic acid as an additive, in chloroform as the solvent at room temperature, achieving enantioselectivities up to 96%. Theoretical calculations are used to justify the observed sense of the stereoinduction.
Resumo:
A simple change in the polarity of the solvent allows both enantiomers of substituted succinimides to be obtained in the enantioselective conjugate addition reaction of aldehydes, mainly α,α-disubstituted, to maleimides catalysed by chiral carbamate-monoprotected trans-cyclohexane-1,2-diamines. Using a single enantiomer of the organocatalyst, both enantiomers of the resulting Michael adducts are obtained in high yields by simply changing the reaction solvent from aqueous DMF (up to 84 % ee) to chloroform (up to 86 % ee). Theoretical calculations are used to explain this uncommon reversal of the enantioselectivity; two transition state orientations of different polarities are differently favoured in polar or nonpolar solvents.
Resumo:
[From the Introduction]. The EC Treaty in its present version contains a number of environmental principles. The following contribution will try to retrace the origins of these principles in the EC Treaty and how they were developed by the EC institutions and in particular by the Commission. This discussion concerns the principles of integration[1], prevention[2] and precaution[3], the principle that environmental damage should as a priority be rectified at source[4] and the polluter-pays principle[ 5].
Resumo:
From the Introduction. According to Article 220 of the EC Treaty, the Court of Justice and the Court of First Instance (hereinafter CFI) “each within its jurisdiction, shall ensure that in the interpretation and application of [the EC] Treaty the law is observed”. The “pre-Nice” allocation of jurisdiction between the two Community courts can be summarized as follows. At Court of Justice level, mention should first of all be made of references for a preliminary ruling. A national court, in a case pending before it, can - or in some circumstances must - refer to the Court of Justice a question relating to the interpretation of provisions of the EC Treaty or of secondary Community law, or relating to the validity of provisions of secondary Community law.1 Moreover, the Court of Justice ensures the observance of the law in the context of actions for annulment or failure to act brought before it by the Community institutions, the European Central Bank (hereinafter ECB) and the Member States.2 These actions concern, respectively, the legality of an act of secondary Community law and the legality of the failure of the institution concerned to adopt such act. The Court of Justice also has jurisdiction in actions brought by the Commission or by a Member State relating to the infringement of Community law by a Member State (hereinafter infringement actions)3 and in actions relating to compensation for non-contractual damage brought by Member States against the Community.4 Finally, as regards the jurisdiction of the Court of Justice, mention should be made of appeals which can be lodged on points of law only against rulings of the CFI.5
Resumo:
Introduction. The present overview covers the period starting from 2000 until the end of 2005.1 This is the follow-up to our overview covering the 1995-1999 period.2 The first striking feature of the present contribution is that it has to deal with almost 3,5 times as many cases as the previous one. Hence, the ECJ has gone from deciding 40 cases in the five year period between 1995- 1999 to deciding over 140 cases based on Art 49 between 2000-2005. This confirms, beyond any doubt, the tendency already observed in our previous overview, that a “third generation” case law on services is being developed at a very rapid pace by the ECJ. This third generation case law is based on the idea that Article 49 EC is not limited to striking down discriminatory measures but extends to the elimination of all hindrances to the free provision of services. This idea was first expressed in the Tourist Guide cases, the Greek and Dutch TV cases and most importantly in the Säger case.3 It has been confirmed ever since. As was to be expected, this broad brush approach of the Court’s has led to an ever-increasing amount of litigation reaching Luxemburg. It is clear that, if indicators were used to weight the importance of the Court’s case law during the relevant period, services would score much higher than goods, both from a quantitative and from a qualitative perspective.4 Hence, contrary to the previous overview, this one cannot deal in detail with any of the judgments delivered during the reference period. The aim of the present contribution is restricted to presenting the basic trends of the Court’s case law in the field of services Therefore, the analysis follows a fundamentally horizontal approach, fleetingly considering the facts of individual cases, with a view to identifying the conceptual premises of the Court’s approach to the free movement of services. Nonetheless, the substantial solutions adopted by the Court in some key topics, such as concession contracts, healthcare services, posted workers and gambling, are also presented as case studies. In this regard, the analysis is organized in four sections. First we explore the (ever expanding) scope of the freedom to provide services (Section 2), then we go on to identify the nature of the violations and of justifications thereto (Section 3), before carrying out some case studies to concretely illustrate the above (Section 4). Then, for the sake of completeness, we try to deduce the general principles running through the totality of the relevant case law (Section 5). Inevitably, some concluding remarks follow (Section 6).5
Resumo:
From the Introduction. By virtue of Council Regulation No. 1/2003, as of 1st May 2004 the full application of EC competition law will be entrusted to national competition authorities (hereinafter NCAs) and national courts. The bold reform of EC competition law enforcement adheres to the system of executive federalism1 which characterises the EC legal system. The repartition of competences within the Community allocates implementation of Community law mainly at Member States level. Pursuant to Article 10 EC, they are responsible for the implementation of the measures which have been adopted at Community level for the achievement of the objectives specified in the EC Treaty. Consequently, the attainment of the Community objectives depends very much upon the cooperation of national authorities, which act in accordance with their own national procedural rules.2 The various national procedural rules present themselves as conduits through which Community law is implemented and enforced. While as a rule Community law is not designed to alter national procedural rules, the Community legal order cannot afford to leave national procedural rules untouched when they are liable to hamper the effective application of Community law....For reason of space, this contribution intends only to highlight some aspects of Regulation No. 1/2003 with regard to which general principles of Community law are able to condition national procedural rules.