Diagnóstico de los diferentes tipos de agresividad del perro dirigida hacia las personas

El objetivo de este trabajo es describir los diferentes tipos de agresividad del perro dirigida hacia las personas. La agresividad puede clasificarse en dos grandes grupos: agresividad debida a problemas orgánicos y agresividad sin causa orgánica. La agresividad sin causa orgánica es la más frecuente e incluye agresividad por dominancia, agresividad maternal, agresividad por miedo, agresividad por competencia dirigida hacia niños y agresividad territorial. El diagnóstico de cada uno de estos tipos se basa en la postura adoptada por el perro durante el episodio de agresividad, las circunstancias que desencadenan la conducta agresiva y la conducta del perro entre episodios de agresividad.The aim of this paper is to describe the diffirent types of human-directed aggresion in dogs. Aggression can be broadly divided in medical and non-medical. Non-medical aggression is the most common type and includes dominance aggression, maternal aggression, fiar aggression, sibling rivalry and territorial aggression. The diagnosis is based on the posture of the dog whtle being aggressive, the circumstances in which aggression appears and the behaviour of the dog between aggressive incidents

Introducción al diagnóstico y tratamiento del marcaje territorial con orina en el gato

El marcaje territorial con orina es uno de los problemas de comportamiento más frecuentes en el gato. Si bien es más frecuente en machos no castrados, puede manifestarse también en machos castrados y en hembras. Los principales criterios de diagnóstico que permiten distinguirlo de otros problemas de eliminación son la presencia o ausencia de heces junto con la orina, ia localización de la orina, el volumen de orina y la postura del animal al orinar. La castración soluciona el problema en el 90 % de los animales aproximadamente. En aquellos animales que no responden a la castración o a los que no se desea castrar, los tranquilizantes son el tratamiento de elección, puesto que son igualo más eficaces que los progestágenos sintéticos y presentan menos efectos secundarios.Urine marking is one of the most common behavioural problems in cats. Although it is most frequent in intact males, urine marking can also occur in both castrated males and females. The amount and location of urine, the pasture of the cat while urinating and thepresence or absence of faeces are important criteria to rule out any other cause of inappropriate elimination. Urine marking is treated by castration, which is effective in 90 % of cases. When castration is unsuccesful or undesired, anxiolytic drugs are the treatment of choice, because they are at least as effictive as synthetic progestins and have less side effects

La temporalidad del subjuntivo en relación con el nodo «flexión».

Sin resume

Streptomyces coelicolor: DNA methylation and differentiation

DNA cytosine methylation is an epigenetic modification regulating many biological processes in eukaryotes, including chromatin organization, genome maintenance and gene expression. The role of DNA cytosine methylation in prokaryotes has not been deeply investigated. In Escherichia coli it was recently demonstrated that cytosine methylation regulates gene expression during stationary phase [1] and that an induced state of cytosine hypermethylation leads to chromosomal DNA cleavage and cell death [2]. Streptomyces coelicolor is a mycelial soil microorganism, which exhibits a complex life cycle that includes three different cell types: unigenomic spores, a compartmentalized mycelium (MI) and a multinucleated mycelium (substrate and aerial mycelium, MII) [3]. The importance of DNA methylation was already described in Streptomycetes [4], but its biological role remains unknown. The main objectives of this study are to analyze cytosine methylation pattern of Streptomyces coelicolor M145 during growth in liquid and on solid media, and to investigate the relationship between DNA cytosine methylation and morphological/physiological differentiation. Cytosine methylation of total genomic DNA extracted from different developmental stages was investigated by dot-blot experiments using antibody anti-5-methylcytosine. Cytosine methylome was analyzed by BiSulphite sequencing. The biological effect of cytosine methylation was studied adding 5-aza-2\u2019-deoxycytidine (aza-dC), a hypomethylating agent, to the cultures. Dot blot analysis revealed that the level of cytosine methylation changes during development (MI, MII and spores). Specifically, DNA methylation is higher at the MI stage than in the MII or spores. BiSulphite sequencing revealed that 30% of S. coelicolor genes contained a methylated motif in their upstream regions. Genes harbouring these motifs included genes related to differentiation (aerial mycelium formation and sporulation), genes involved in DNA repair/replication/condensation, as well as genes encoding proteins with unknown functions. Phenotypic analyses of cultures treated with aza-dC demonstrated that DNA methylation influences germination, aerial mycelium formation and sporulation on solid medium and antibiotic production both, on solid and in liquid medium. Overall, our preliminary results suggest a role for DNA cytosine methylation in morphological and physiological differentiation of S. coelicolor. Further experiments are ongoing to demonstrate the molecular mechanisms and pathways behind the observed phenotypes

Protein phosphorylation plays a major rol in streptomyces differenciation

Comunicaciones a congreso

Epigenetic control of Streptomyces coelicolor differentiation

DNA cytosine methylation is one of the most important epigenetic modifications in eukaryotes regulating chromatin organization, genome maintenance and gene expression. The role of DNA cytosine methylation in prokaryotes has not been deeply investigated. In Escherichia coli cytosine methylation regulates gene expression during the stationary phase and cytosine hypermethylation leads to chromosomal DNA cleavage and cell death. Streptomyces coelicolor is a mycelial soil microorganism, which exhibits a complex life cycle that includes three different cell types: unigenomic spores, a compartmentalized mycelium (MI) and a multinucleated mycelium (substrate and aerial mycelium, MII). The importance of DNA methylation was already described in Streptomycetes, but its biological role remained unknown. The main objectives of this study were to analyze the pattern of cytosine methylation in Streptomyces coelicolor and to investigate the relationship between DNA cytosine methylation and morphological/physiological differentiation. Dot-blot analysis of genomic DNA using antibody anti-5-methylcytosine revealed that DNA methylation is modulated during hyphae differentiation. Specifically DNA cytosine methylation is higher at the MI stage than in the MII or spores. Cytosine methylome was investigated by bisulphite DNA sequencing showing that 30% of S. coelicolor genes contain a methylated motif in their upstream region. The biological effect of cytosine methylation was studied using 5-aza-2’-deoxycytidine (aza-dC), a hypomethylating agent. Phenotypic analyses of cultures treated with aza-dC demonstrated that they were impaired in germination, aerial mycelium formation and sporulation. In addition, they showed a strong reduction in antibiotic production. Overall, our results suggest a role for DNA cytosine methylation in morphological and physiological differentiation of S. coelicolor. Further experiments are ongoing to characterize the molecular mechanisms and pathways behind the observed phenotypes

A low energy core-collapse supernova without a hydrogen envelope

The final fate of massive stars depends on many factors, including mass, rotation rate, magnetic fields and metallicity. Theory suggests that some massive stars (initially greater than 25-30 solar masses) end up as Wolf-Rayet stars which are deficient in hydrogen because of mass loss through strong stellar winds. The most massive of these stars have cores which may form a black hole and theory predicts that the resulting explosion produces ejecta of low kinetic energy, a faint optical display and a small mass fraction of radioactive nickel(1,2,3). An alternative origin for low energy supernovae is the collapse of the oxygen-neon core of a relatively lowmass star (7-9 solar masses) through electron capture(4,5). However no weak, hydrogen deficient, core-collapse supernovae are known. Here we report that such faint, low energy core-collapse supernovae do exist, and show that SN2008ha is the faintest hydrogen poor supernova ever observed. We propose that other similar events have been observed but they have been misclassified as peculiar thermonuclear supernovae (sometimes labelled SN2002cx-like events(6)). This discovery could link these faint supernovae to some long duration gamma-ray bursts. Extremely faint, hydrogen-stripped core-collapse supernovae have been proposed to produce those long gamma-ray bursts whose afterglows do not show evidence of association with supernovae (7,8,9).Comment: Submitted 12 January 2009 - Accepted 24 March 200