1,634 research outputs found

    Hyperbolastic type-III diffusion process: Obtaining from the generalized Weibull diffusion process

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    The modeling of growth phenomena has become a matter of great interest in many different fields of application and research. New stochastic models have been developed, and others have been updated to this end. The present paper introduces a diffusion process whose main characteristic is that its mean function belongs to a wide family of curves derived from the classic Weibull curve. The main characteristics of the process are described and, as a particular case, a di usion process is considered whose mean function is the hyperbolastic curve of type III, which has proven useful in the study of cell growth phenomena. By studying its estimation we are able to describe the behavior of such growth patterns. This work considers the problem of the maximum likelihood estimation of the parameters of the process, including strategies to obtain initial solutions for the system of equations that must be solved. Some examples are provided based on simulated sample paths and real data to illustrate the development carried out.This work was supported in part by the Ministerio de Economía, Industria y Competitividad, Spain, under Grant MTM2017-85568-P

    Caracterización de endófitos simbióticos aislados de leguminosas nativas de la Amazonía peruana

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    Se aisló y determino la capacidad infectiva y efectiva en FBN de 10 cepas endófitas, de tres especies de leguminosas (macrosimbiontes): Inga edulis C. Mart.; Desmodium adscendens (Sw.) DC.; Ormosia coccinea (Aubl.) Jacks., aisladas de bosques primarios, secundarios e intervenidos. De las 10 cepas aisladas se logró identificar genotípicamente 06. Las 10 cepas aisladas (microsimbiontes) fueron inoculadas en sus respectivos tratamientos (macrosimbiontes) en condiciones controladas, reportándose infectividad (nódulos) en 4 de estos. Se registró diferencia significativa en las cepas IeBS-C1 y IeBS-C2 frente al control empleado, pero ambas tienen la misma efectividad (CFN) con o sin la presencia de los endófitos simbióticos. Se registró diferencia significativa en las cepas IeBI-C1 y IeBI-C2 frente al control empleado, porque ambas tienen mejor efectividad (CFN) con la presencia de los endófitos simbióticos. No se registró diferencia significativa en las cepas DaBS-C1, DaBs-C2, DaBI-C1 y DaBI-C2 frente al control empleado, todas tienen la misma efectividad (CFN) con o sin la presencia de los endófitos simbióticos

    Sesquiterpene lactones affect the redox system of trypanosoma cruzi

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    Chagas disease is caused by Trypanosoma cruzi (T. cruzi) and affects millions of people worldwide, mostly in Latin America. Despite its sanitary importance, there are currently only two drugs available for its treatment: benznidazole and nifurtimox, both exhibiting serious adverse effects on patients. In order to complete its life cycle, T. cruzi faces extreme environmental conditions ?i.e. oxidative stress- as it propagates from an insect vector to a mammalian host, driving the transition from non-infective epimastigote to the infective form trypomastigote. It is known that the antioxidant defense system in the trypanosomatids is different from that in mammalian cells since the parasites have exclusive molecules and reducing enzymes. Because of this, the parasite redox machinery is an attractive target for antiparasitic therapies. The sesquiterpene lactone dehydroleucodine (DhL), is a trypanocidal molecule containing an alpha-methylene group that could react with sulfhydryl groups of key redox enzymes. This study was focused on elucidating the DhL mechanism of action and extended to ten DhL derivatives (DC-X1 to DC-X10) obtained by chemical substitutions on the methylene group. We firstly confirmed an antiproliferative effect of DhL and its chemical derivatives, being DC- X6 one of the most active. The effect of DhL and DC-X6 was blocked by reduced glutathione, suggesting that compounds are reactive to sulfhydryl groups of certain molecules. Moreover, parasites overexpressing reducing enzymes, such as Tc-CPX, showed a protective effect against these STLs. Consistent with these results, both STLs increased ROS concentration in the wild type parasites. These results indicate that STLs induce oxidative stress on the parasites, possibly by affecting some crucial enzymes of the redox system.Fil: Gomez, Jessica Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Histología y Embriología D/mend Dr.m.burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Guarise, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Histología y Embriología D/mend Dr.m.burgos; ArgentinaFil: Tello Faral, P.. Instituto Pasteur de Montevideo; UruguayFil: Robello, Carlos. Instituto Pasteur de Montevideo; UruguayFil: Caballero, P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Histología y Embriología D/mend Dr.m.burgos; ArgentinaFil: Cifuente, Diego Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Sosa, M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Histología y Embriología D/mend Dr.m.burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Barrera, Patricia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Histología y Embriología D/mend Dr.m.burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaXXXVII Reunión Científica Anual de la Sociedad de Biología de CuyoSan LuisArgentinaSociedad de Biología de Cuy

    Predicting the Impact of Climate Change on the Distribution of Rhipicephalus sanguineus in the Americas

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    Climate change may influence the incidence of infectious diseases including those transmitted by ticks. Rhipicephalus sanguineus complex has a worldwide distribution and transmits Rickettsial infections that could cause high mortality rates if untreated. We assessed the potential effects of climate change on the distribution of R. sanguineus in the Americas in 2050 and 2070 using the general circulation model CanESM5 and two shared socioeconomic pathways (SSPs), SSP2-4.5 (moderate emissions) and SSP2-8.5 (high emissions). A total of 355 occurrence points of R. sanguineus and eight uncorrelated bioclimatic variables were entered into a maximum entropy algorithm (MaxEnt) to produce 50 replicates per scenario. The area under the curve (AUC) value for the consensus model (\u3e0.90) and the partial ROC value (\u3e1.28) indicated a high predictive capacity. The models showed that the geographic regions currently suitable for R. sanguineus will remain stable in the future, but also predicted increases in habitat suitability in the Western U.S., Venezuela, Brazil and Bolivia. Scenario 4.5 showed an increase in habitat suitability for R. sanguineus in tropical and subtropical regions in both 2050 and 2070. Habitat suitability is predicted to remain constant in moist broadleaf forests and deserts but is predicted to decrease in flooded grasslands and savannas. Using the high emissions SSP5-8.5 scenario, habitat suitability in tropical and subtropical coniferous forests and temperate grasslands, savannas, and shrublands was predicted to be constant in 2050. In 2070, however, habitat suitability was predicted to decrease in tropical and subtropical moist broadleaf forests and increase in tropical and subtropical dry broadleaf forests. Our findings suggest that the current and potential future geographic distributions can be used in evidence-based strategies in the design of control plans aimed at reducing the risk of exposure to zoonotic diseases transmitted by R. sanguineus

    Low-Scale Expression and Purification of an Active Putative Iduronate 2-Sulfate Sulfatase-Like Enzyme from Escherichia coli K12

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    The sulfatase family involves a group of enzymes with a large degree of similarity. Until now, sixteen human sulfatases have been identified, most of them found in lysosomes. Human deficiency of sulfatases generates various genetic disorders characterized by abnormal accumulation of sulfated intermediate compounds. Mucopolysaccharidosis type II is characterized by the deficiency of iduronate 2-sulfate sulfatase (IDS), causing the lysosomal accumulation of heparan and dermatan sulfates. Currently, there are several cases of genetic diseases treated with enzyme replacement therapy, which have generated a great interest in the development of systems for recombinant protein expression. In this work we expressed the human recombinant IDS-Like enzyme (hrIDS-Like) in Escherichia coli DH5α. The enzyme concentration revealed by ELISA varied from 78. 13 to 94. 35 ng/ml and the specific activity varied from 34. 20 to 25. 97 nmol/h/mg. Western blotting done after affinity chromatography purification showed a single band of approximately 40 kDa, which was recognized by an IgY polyclonal antibody that was developed against the specific peptide of the native protein. Our 100 ml-shake-flask assays allowed us to improve the enzyme activity seven fold, compared to the E. coli JM109/pUC13-hrIDS-Like system. Additionally, the results obtained in the present study were equal to those obtained with the Pichia pastoris GS1115/pPIC-9-hrIDS-Like system (3 L bioreactor scale). The system used in this work (E. coli DH5α/pGEX-3X-hrIDS-Like) emerges as a strategy for improving protein expression and purification, aimed at recombinant protein chemical characterization, future laboratory assays for enzyme replacement therapy, and as new evidence of active putative sulfatase production in E. coli. © 2013 The Microbiological Society of Korea and Springer-Verlag Berlin Heidelberg.Fil: Morales Álvarez, Edwin David. Universidad del Quindio; ColombiaFil: Rivera Hoyos, Claudia Marcela. Universidad del Quindio. Facultad de Medicina; ColombiaFil: Baena Moncada, Angelica Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Landázuri, Patricia. Universidad del Quindio. Facultad de Medicina. Centro de Investig. Biomédicas; ColombiaFil: Poutou Piñales, Raúl A.. Pontificia Universidad Javeriana; ColombiaFil: Sáenz Suárez, Homero. Universidad del Quindio; ColombiaFil: Barrera, Luis A.. Pontificia Universidad Javeriana; ColombiaFil: Echeverri Peña, Olga Y.. Pontificia Universidad Javeriana; Colombi

    Mineralocorticoid Receptor Modulation by Dietary Sodium Influences NAFLD Development in Mice

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    Introduction and Objectives Nonalcoholic-fatty-liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome (MetS). Mineralocorticoid receptor (MR) activation is associated with increased risk of MetS but few studies have assessed the role of liver MR on NAFLD. We aimed to evaluate the effect of MR modulation by sodium intake in liver injury in experimental models of NAFLD. Materials and Methods C57BL/6J mice were fed either a high-fat-diet (HFD) or a choline/methionine deficient (MCD) diet with different sodium concentrations. Hepatic concentration of lipid species, serum aldosterone levels, expression of MR, proinflammatory and profibrotic markers and liver histology were assessed. Results Mice fed with High-Na+/HFD showed a lower MR expression in liver (p = 0.01) and less steatosis on histology (p = 0.04). Consistently, animals from this group exhibited lower levels of serum aldosterone (p = 0.028) and lower hepatic triglyceride content (p = 0.008). This associated to a reduced expression of lipogenic genes, significant changes in lipid subspecies, lower HOMA-IR (p < 0.05), and lower expression of pro-inflammatory and profibrotic markers compared to those mice fed a Low-Na+/HFD. Additionally, mice fed a High-Na+/HFD showed higher expression of salt-inducible kinase (SIK)-1 and lower expression of serum-and-glucocorticoid-inducible kinase (SGK)-1. Similar results were observed with the MCD diet model. Conclusion We identified in two experimental models of NAFLD that High-Na+ diet content is associated to lower serum aldosterone levels and hepatic MR downregulation, associated to decreased steatosis and reduced de novo hepatic lipogenesis, proinflammatory and profibrotic markers. Decreased activation of hepatic MR seems to generate beneficial downstream inhibition of lipogenesis in experimental NAFLD.This work was funded, in part, by grants from the Chilean Government [FONDECYT #1150327 and #1191145 to M.A.; #1200227 to JPA; #1190419 to R.B and #1191183 to F.B.; #1211879 to D.C.) and the Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, AFB170005, CARE Chile UC)]. MA is part of the European- Latin American ESCALON consortium funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement no. 825510. Funding from Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT971-16 to P.A.), MCIU/AEI/FEDER, UE (RTI2018-095134-B-100 to P.A) is also acknowledged

    Human sulfatase transiently and functionally active expressed in E. coli K12

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    The recombinant human iduronate 2-sulfate sulfatase (hrIDS) was transiently and functionally active expressed in E. coli K12. The enzyme activity (crude extract) at 100 ml and 400 ml oscillated between 0.25 and 10.58 nmol h-1 mg-1. The wide Western-blot peptide profile suggest that hrIDS is proteolitically processed \u201crandomly\u201d which agrees with the ultrafiltration assay in which the hrIDS activity was found in all fractions (&lt;30kDa, 30-100kDa and &gt;100kDa). No glycation sites were found by computer analysis of the hIDS sequence; discarding the possibility of marks for glycation and proteolytic processing

    Characterization of a Novel Interaction between Bcl-2 Members Diva and Harakiri

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    Interactions within proteins of the Bcl-2 family are key in the regulation of apoptosis. The death-inducing members control apoptotic mechanisms partly by antagonizing the prosurvival proteins through heterodimer formation. Structural and biophysical studies on these complexes are providing important clues to understand their function. To help improve our knowledge on protein-protein interactions within the Bcl-2 family we have studied the binding between two of its members: mouse Diva and human Harakiri. Diva has been shown to perform both prosurvival and killing activity. In contrast, Harakiri induces cell death by interacting with antiapoptotic Bcl-2 members. Here we show using ELISA and NMR that Diva and Harakiri can interact in vitro. Combining the NMR data with the previously reported three-dimensional structure of Diva we find that Harakiri binds to a specific region in Diva. This interacting surface is equivalent to the known binding area of prosurvival Bcl-2 members from the reported structures of the complexes, suggesting that Diva could function at the structural level similarly to the antiapoptotic proteins of the Bcl-2 family. We illustrate this result by building a structural model of the heterodimer using molecular docking and the NMR data as restraints. Moreover, combining circular dichroism and NMR we also show that Harakiri is largely unstructured with residual (13%) α-helical conformation. This result agrees with intrinsic disorder previously observed in other Bcl-2 members. In addition, Harakiri constructs of different length were studied to identify the region critical for the interaction. Differential affinity for Diva of these constructs suggests that the amino acid sequence flanking the interacting region could play an important role in binding

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

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    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected
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