chemotaxis of rhizobium phaseoli towards flavones and other related compounds

The formation of nitrogen-fixing nodules on leguminous plants is the result of a highly specific interaction between the host plant and the soil bacterium Rhizobium. Two observations suggest that chemotaxis may play a role in the establishment of the legume-Rhizobium symbiosis: 1) The widespread occurence of Rhizobium species with flagella (Gotz, 1982; Carlile. 1980)2) The copious exudation into the soil surrounding legume roots of a wide variety of potentially chemotactic compounds which include amino acids, sugars and sugar-acids. (Beringer et.al.,1979). Recently the plant flavones luteolin (3,44,7 - Tetra - hydroxyflavone) and apigenin (4,5,7 - Trihydroxy-flavone) have been reported as inducers of Rhizobium nodulation genes (Peters, 1986, Rolfe 1986). We report here that R. phaseoli (RP8002) exhibits positive chemotaxis toward both flavones. Other diverse compounds tested elicited different responses. An understanding of the influence of flavones in two events such as chemotaxis and nodulation efficiency can be valuable to clarify their action in the intricate legume-rhizobia interaction

Computational Protein Design and Molecular Dynamics Simulations: A Study of Membrane Proteins, Small Peptides and Molecular Systems

Molecular design and modeling can provide stringent assessment of our understanding of the structure and function of proteins. Due to the subtleness of the interactions that largely stabilize proteins, computational methods have been particularly valuable in establishing practical, formal and physically grounded protocols to study the structure and function of these biomolecules. Especifically, computational protein design seeks to identify sequences that fold into a desired structure and have specific structural and functional properties using computational methodologies. Among current techniques, an entropy-based formalism that efficiently determines the number and composition of sequences satisfying a predefined set of constraints seems particularly promising and powerful. Complementary to this methodology are the well-established molecular dynamics simulation techniques that have been extensively used to study structure, function and dynamics of biologically relevant systems. Herein different studies of systems using computational techniques to address particular molecular problems are described. Efforts to redesign membrane proteins to generate water-soluble variants were applied to a widely studied pentameric ligand-gated ion channel, the nicotinic acetylchoilne receptor (nAChR). NMR structures and binding studies demostrated the robustness and applicability of the computational design approach. Toward the creation of water-soluble variants of a G protein–coupled receptor (GPCR), comparative modeling and docking calculations were used to investigate the structure of the human μ opioid receptor and presented in light of previous mutagenesis studies of structure and agonist-induced activation. Candidate peptides for possible therapeutic agents were computationally analyzed. Peptide design, loop modeling and MD simulations were applied to investigate the stromal cell-derived factor-1&a; (SDF-1&a;). SDF-1&a; displays promising therapeutic benefits to treat blood-supply related heart disease and elicit growth of microvasculature. Simplified analogs of SDF-1&a; exhibit enhanced therapeutic properties in cell-based assays. MD simulations provide insights about the molecular features of this enhancement. One simplified peptide offers a potentially clinically translatable neovasculogenic therapy. Lastly, MD simulations were utilized to analyze a molecule with hindered internal rotors, a tribenzylamine hemicryptophane. The molecule was characterized by different experimental and computational techniques. The structural and dynamic features of the hemicryptophane molecule make it an attractive starting point for controlling internal rotation of aromatic rings within molecular systems

Análisis de la distribución espacial de la malaria en el departamento de chocó para el año 2016

(Eng) The present investigation has as purpose the estimation of a generalized linear spatial regression model of Poisson distribution that allows to explain the geographic-spatial behavior of malaria for the department of Chocó for the year 2016. The probability maps were the result of statistical techniques spatial data type Lattice such as criteria of figures, distances and physical contiguity, in order to determine the existence of a spatial relationship of the disease in question. To verify this spatial autocorrelation among the municipalities of the department of Chocó, it was carried out based on the statistical interaction of sanitary, environmental and demographic variables such as the population of each municipality. However, it was necessary to perform a Gaussian anamorphosis process to guarantee the normalization of the data in standardized morbidity rates (SMR) and thus identify the statistical structure of the data that for this year were from a Poisson distribution. The study allowed the identification of positive spatial autocorrelation in some municipalities of Chocó, such as Paimado, Istmina and Tado, where ma - laria is more likely to occur due to its municipal proximity according to the physical relationship of certain study variables. It was obtained as a result that the variables that best explain malaria in the Chocó municipalities are the coverage of forests and unsatisfied basic needs that give as a product the map of spatial autocorrelation and the map of probability of occurrence among the municipalities of the department.(Spa) La presente investigación tiene como propósito la estimación de un modelo de regresión espacial lineal gen - eralizado de distribución Poisson que permita explicar el comportamiento espacio-geográfico de la malaria para el departamento de Chocó para el año 2016. Los mapas de probabilidad fueron resultado de técnicas de estadística espacial en datos tipo Lattice tales como criterios de figuras, distancias y de contigüidad física, con el fin de determinar la existencia de una relación espacial de la enfermedad en mención. Para verificar dicha autocorrelación espacial entre los municipios del departamento de Chocó se realizó basado en la interacción estadística de variables sanitarias, ambientales y demográficas como la población de cada municipio. Sin em - bargo, fue necesario realizar un proceso de anamorfosis gaussiana para garantizar la normalización de los datos en tasas de morbilidad estandarizada (SMR) y así identificar la estructura estadística de los datos que para este año fueron provenientes de una distribución Poisson. El estudio permitió identificar autocorrelación espacial positiva en algunos municipios del Chocó como Paimado, Istmina y Tado donde la malaria tiene mayor prob - abilidad de ocurrencia por su cercanía municipal de acuerdo a la relación física de ciertas variables del estudio. Se obtuvo como resultado que las variables que mejor explican espacialmente la malaria para los municipios del Chocó son la cobertura de bosques y necesidades básicas insatisfechas que dan como producto el mapa de autocorrelación espacial y el mapa de probabilidad de ocurrencia entre los municipios del departamento

Computational Design of Membrane Proteins

Membrane proteins are involved in a wide variety of cellular processes, and are typically part of the first interaction a cell has with extracellular molecules. As a result, these proteins comprise a majority of known drug targets. Membrane proteins are among the most difficult proteins to obtain and characterize, and a structure-based understanding of their properties can be difficult to elucidate. Notwithstanding, the design of membrane proteins can provide stringent tests of our understanding of these crucial biological systems, as well as introduce novel or targeted functionalities. Computational design methods have been particularly helpful in addressing these issues and this review discusses recent studies that tailor membrane proteins to display specific structures or functions, and how redesigned membrane proteins are being used to facilitate structural and functional studies

Evaluación del leasing como medio de financiamiento para la inversión en activos fijos y su impacto en la rentabilidad de la empresa Andina Cargo S.A.C.

El Perú en los últimos 10 años su PBI viene creciendo en forma sostenida, este desarrollo económico ha empujado a la expansión de las actividades comerciales en el país, como viene sucediendo en los negocios de RITAIL desde el 2010 hasta la fecha. Este crecimiento comercial ha permitido que se dé un importante desarrollo del transporte de carga, en el Perú de hoy en día, el 80% de las mercancías se traslada en camiones, así mismo según el INEI el crecimiento promedio de la industria del transporte de carga está en el orden del 8% anual, teniendo un parque automotor con vehículos nuevos que representan un 50%, pero aún hay un 43% de la flota con antigüedad mayor a 10 años. El presente trabajo de investigación tiene como finalidad de demostrar la mejor opción de financiamiento en activos fijos mediante Leasing con las mejores condiciones y tasas que ofrecen las entidades financieras, realizando una evaluación de Proyectos de inversión con diferentes vidas útiles, para poder incrementar la utilidad y la disminución de los costos de la empresa, por lo tanto se analizó 3 alternativas de financiamiento, la primera con un Leasing financiero con vida útil de dos años, la segunda de tres años y la tercera de cuatro años. Sobre esto, se obtuvo que la mejor alternativa que tiene los socios para su proyecto de inversión, es apalancándose a través de un leasing por un periodo de cuatro años con el Banco Continental del Perú.Tesi

Printed antenna for satellite communications

2010 Proceedings of the Fourth European Conference on Antennas and Propagation (EuCAP

Human μ Opioid Receptor Models with Evaluation of the Accuracy Using the Crystal Structure of the Murine μ Opioid Receptor

Models of the human μ opioid receptor were constructed using available G-protein-coupled receptor (GPCR) structures using homology (comparative) modeling techniques. The recent publication of a high-resolution crystal structure of a construct based on the murine μ opioid receptor offers a unique opportunity to evaluate the reliability of the homology models and test the relevance of introducing more templates (known structures) to increase the accuracy of the comparative models. In the first model two templates were used: the β2 adrenergic and bovine rhodopsin receptors. For the second model, four templates were utilized: the β2adrenergic, bovine rhodopsin, β1 adrenergic, and A2A adenosine receptors. Including additional templates improved the accuracy of structural motifs and other features of the model when the same sequence alignment was used. The predicted structures were especially relevant in the case of important receptor regions such as the DRY motif, which has been associated with receptor activation. Additionally, this study showed that receptor sequence similarity is crucial in homology modeling, as indicated in the case of the highly diverse EC2 loop. This study demonstrates the reliability of the homology modeling technique in the case of the μ opioid receptor, a member of the rhodopsin-like family class of GPCRs. The addition of more templates improved the accuracy of the model. The findings regarding the modeling has significant implication to other GPCRs where the crystal structure is still unknown and suggest that homology modeling techniques can provide high quality structural models for interpreting experimental findings and formulating structurally based hypotheses regarding the activity of these important receptors

Effects of flooding on mental health: a case-control study

3rd International Congress on Neurobiology, Psychopharmacology & Treatment guidance (May 30th - June 2nd, 2013)Background: Post-disaster mental health problems may affect population in different ways. Population exposure to a natural disaster has been associated with psychological distress, in particular, in the development of Posttraumatic Stress Disorder (PTSD). Most people experience distress after their exposure to an extreme event. For people with good psychosocial resilience and access to social support, mental health problems can be relatively less important since supporting relationships and inner capabilities may begin the adaptation processes. Mental disorders occur often, but less commonly than dis-tress, and in some cases they may require intensive and long term continuing interventions and treatment