Study of the Putative Fusion Regions of the preS Domain of Hepatitis B Virus

In a previous study, it was shown that purified preS domains of hepatitis B virus (HBV) could interact with acidic phospholipid vesicles and induce aggregation, lipid mixing and leakage of internal contents which could be indicative of their involvement in the fusion of the viral and cellular membranes (Núñez, E. et al. 2009. Interaction of preS domains of hepatitis B virus with phospholipid vesicles. Biochim. Biophys. Acta 17884:417-424). In order to locate the region responsible for the fusogenic properties of preS, five mutant proteins have been obtained from the preS1 domain of HBV, in which 40 amino acids have been deleted from the sequence, with the starting point of each deletion moving 20 residues along the sequence. These proteins have been characterized by fluorescence and circular dichroism spectroscopy, establishing that, in all cases, they retain their mostly non-ordered conformation with a high percentage of β structure typical of the full-length protein. All the mutants can insert into the lipid matrix of dimyristoylphosphatidylglycerol vesicles. Moreover, we have studied the interaction of the proteins with acidic phospholipid vesicles and each one produces, to a greater or lesser extent, the effects of destabilizing vesicles observed with the full-length preS domain. The ability of all mutants, which cover the complete sequence of preS1, to destabilize the phospholipid bilayers points to a three-dimensional structure and/or distribution of amino acids rather than to a particular amino acid sequence as being responsible for the membrane fusion process

Socio-Demographic Variables and Successful Aging of the Angolan Elderly

The proportion of elderly people is growing faster than any other age group. Amongst them, the group of oldest old is indeed the segment of the elderly population with the fastest growth rate. The increase in the proportion of elderly in the Angolan population makes research on this area badly needed. Within the theoretical framework of successful aging, the study aims to test for sociodemographic group differences in perceived health, life satisfaction, and social relations in Angolan elderly. The dependent variables are three of the components of what has been called successful aging. Data came from a cross-sectional survey of elderly people living in Luanda. 1003 Angolan elderly were surveyed on sociodemographic information, perceived health, life satisfaction, and social support. MANOVAs were calculated to test for mean differences in the dependent variables. Results permit to conclude that the factors associated with the largest differences on the Angolan elderly’s quality of life and social relations were age (becoming oldest old) and institutionalization. The interactions of several factors with age pointed out that the oldest old were clearly a group in which the decreased quality of life due to becoming oldest old could not be compensated by other factors, as it was the case in the group of young old

Technological and infrastructure collaborative seismic research in Western Mexico

In February and March 2014, Spanish, Mexican and British scientists and technicians explored the western margin of Mexico, a region with a high occurrence of large earthquakes (> Mw = 7.5) and tsunami generation, on board the British Royal Research Ship James Cook. This successful joint cruise, named TSUJAL, was made possible thanks to a cooperative agreement between NERC and CSIC as part of the Ocean Facilities Exchange Group (OFEG), a major forum of European oceanographic institutions for the exchange of ship time, equipment and personnel. A dense geophysical data set was acquired using for the first time 6 km length seismic streamer facilities from Spain’s Consejo Superior de Investigaciones Cientificas (CSIC), usually operating in the Spanish RV Sarmiento de Gamboa, onboard the British RRS James Cook by solving all mechanical, electrical and electronic problems. The RRS James Cook in turn provides the seismic source and the acoustic, hullmounted echosounder operated by the British Natural Environment Research Council (NERC). Multiscale seismic and echosounder images unravel the subduction geometry, nature of the crust, and evidence faults and mass wasting processes. The data are crucial to estimating fault seismic parameters, and these parameters are critical to carrying out seismic hazard in Mexico, especially when considering largemagnitude earthquakes (Mw 8.0), and to constrain tsunami models.Peer Reviewe

El perfil de los inversores y las entidades financieras: una aproximación desde el entorno de la economía social

Este trabajo pretende presentar un análisis, de los resultados de perfiles de ahorro e inversión de la familia española, específicamente, de aquellas familias que han optado por los servicios financieros ofrecidos por las cajas de ahorros y las cooperativas de crédito, al, entre otros, financiar la compra de la vivienda principal, financiar la compra de otros inmuebles, adquirir créditos de consumo, contratar activos financieros y contratar seguros o planes de pensiones. A través de un análisis de conglomerados, efectuado sobre los datos publicados en 2006de La Encuesta Financiera de las Familias Españolas, realizada a familias de cuatro estratos de riqueza diferentes, distribuidas en todas las comunidades del país, llevada a cabo en el año 2002 por el Banco de España, se hallan y se describen en esta investigación, las principales características demográficas y de la estructura financiera de 687 familias, que de un total de 5143, han preferido y efectivamente seleccionado a las cooperativas de crédito o a las cajas de ahorro, como proveedoras de los más básicos servicios financieros.This paper aims to present an analysis of the saving and investment profiles of the Spanish family, more specifically, those families who have opted for the financial services offered by savings and credit cooperatives in order to finance the purchase of a primary residence or other property, acquire consumer credit, purchase financial assets or acquire insurance or pension plans. Through a cluster analysis performed on the data published in The Financial Survey of Spanish Families in 2006, which surveyed families of four different wealth strata throughout the country, conducted in 2002 by the Bank of Spain, this research describes the main demographic characteristics and financial structures of the 687 families, of a total of 5143, that actually preferred credit unions or savings banks as their providers of basic financial services

Multi-GPU Development of a Neural Networks Based Reconstructor for Adaptive Optics

Aberrations introduced by the atmospheric turbulence in large telescopes are compensated using adaptive optics systems, where the use of deformable mirrors and multiple sensors relies on complex control systems. Recently, the development of larger scales of telescopes as the E-ELT or TMT has created a computational challenge due to the increasing complexity of the new adaptive optics systems. The Complex Atmospheric Reconstructor based on Machine Learning (CARMEN) is an algorithm based on artificial neural networks, designed to compensate the atmospheric turbulence. During recent years, the use of GPUs has been proved to be a great solution to speed up the learning process of neural networks, and different frameworks have been created to ease their development. The implementation of CARMEN in different Multi-GPU frameworks is presented in this paper, along with its development in a language originally developed for GPU, like CUDA. This implementation offers the best response for all the presented cases, although its advantage of using more than one GPU occurs only in large networks

Circular dichroism and fluorescence spectroscopic properties of the major core protein of feline immunodeficiency virus and its tryptophan mutants: Assignment of the individual contribution of the aromatic side chains

The gene coding for the major capsid protein of feline immunodeficiency virus (FIV) has been cloned into the expression vector pQE60, which allows protein purification by affinity chromatography on a nitrilotriacetic acid/Ni/agarose column. The gene was expressed in Escherichia coli and the resultant soluble protein (FIV-rp24) purified to electrophoretic homogeneity. The amino-acid composition of the recombinant protein is almost identical to that predicted from the DNA sequence. This protein has two tryptophan residues at positions 40 and 126 that have been replaced by phenylalanine by site-directed mutagenesis to obtain two single mutants and a double mutant. Circular dichroism and fluorescence spectroscopy were employed to study the structural features of FIV-rp24 protein and its tryptophan mutants. The analysis of the CD spectra indicated that α-helix is the major secondary structural element (48-52%) and that the overall three-dimensional structure is not modified by the mutations. The fluorescence emission spectra showed that both tryptophan residues occupy a highly hydrophobic environment. Moreover, the different tyrosine fluorescence intensities of wild-type and mutant proteins are indicative of the existence of resonance energy transfer processes to nearby tryptophan. The individual contributions of each tryptophan residue to the spectroscopic properties of the wild-type protein were obtained from the spectra of all these proteins. Thermal denaturation studies indicate that the two tryptophan residues do not contribute equally to the stabilization of the three-dimensional structure

Effect of fermented, hardened, and dehulled of chickpea (Cicer arietinum) meals in digestibility and antinutrients in diets for tilapia (Oreochromis niloticus)

Among the most typical feed sources for tilapia, plants represent a low-cost source in substituting for traditional high-cost feed ingredients. Fermentation, hardening and dehulling are common grains processing techniques to make plant nutrients available and more digestible to fish. Apparent digestibility coefficients (ADC) of dry matter and protein, and antinutrients (phytic acid and tannins) in fermented, hardened and dehulled chickpea (Cicer arietinum) meals were determined for juvenile Nile tilapia (Oreochromis niloticus). The highest ADC was obtained with processed (fermented, hardened and dehulled) chickpea meals compared with non-processed. Results indicated that fermentation increased the protein content by 13.1%, decreased the content of ash and phytic acid (47.5 and 45%, respectively), and increased the ingredient apparent digestibility of dry matter (ADM) by 23.2%, and the ingredient apparent digestibility of protein (ADP) by 41.9%. Dehulling meal increased the protein (5.7%) and lipid (6.4%) content of chickpea grains; decreased fiber, ash and tannin content (75.3%, 19.1%, and 84.5%, respectively); and increased ADM by 12.8%, and ADP by 10.4%. We conclude that fermented, hardened and dehulled chickpea meals represent a potential alternative in diets for juvenile O. niloticus

Expression and structural properties of a chimeric protein based on the ectodomains of E1 and E2 hepatitis C virus envelope glycoproteins

Hepatitis C virus encodes two enveloped glycoproteins, E1 and E2, which are involved in viral attachment and entry into target cells. We have obtained in insect cells infected by recombinant baculovirus a chimeric secreted recombinant protein, E1341E2661, containing the ectodomains of E1 and E2. The described procedure allows the purification of approximately 2 mg of protein from 1 L of culture media. Sedimentation velocity experiments and SDS-PAGE in the absence of reducing agents indicate that the protein has a high tendency to self-associate, the dimer being the main species observed. All the oligomeric forms observed maintain a conformation which is recognized by the conformation-dependent monoclonal antibody H53 directed against the E2 ectodomain. The spectroscopic properties of E1341E2661 are those of a three-dimensionally structured protein. Moreover, the chimeric protein is able to bind to human antibodies present in HCV-positive human sera. Accordingly, this chimeric soluble polypeptide chain may be a valuable tool to study the structure-function relationship of HCV envelope proteins

Fusogenic properties of the ectodomains of hepatitis C virus envelope proteins

We have used an isolated chimeric protein E1340E2661 that includes the ectodomains of the envelope proteins of epatitis C virus to study its interaction with model membranes. E1340E2661 has some of the membrane destabilization properties, vesicle aggregation, lipid mixing and the release of internal aqueous content, which have previously been ascribed to fusion proteins. The effects are preferentially produced on vesicles of acidic phospholipids which would indicate the importance of the electrostatic interactions. In fact, an increase of the ionic strength of the buffer induced a considerable decrease of the destabilizing properties. Moreover, fluorescence polarization studies show that the recombinant protein reduces the amplitude of the thermal transition of dimyristoylphosphatidylglycerol vesicles and increases the transition temperature at pH 5.0 in a dose-dependent manner, indicating its insertion into the bilayer. Furthermore, a decrease of the pH induces a onformational change in the protein structure as videnced by fluorescence of tryptophan residues and 4,4-bis(1-anilinonaphthalene-8-sulfonate). A model for the fusion of hepatitis C virus with the host cell membrane can be postulated. The dissociation of E1E2 dimers would uncover the fusion peptides which can then interact with the polar lipid heads of the outer leaflet of the lipid bilayer and next insert into the hydrophobic moiety producing the destabilization of the bilayer which finally leads to fusion