691 results on '"Vargas, Rodrigo"'
Search Results
652. Application of Metagenomics to Chilean Aquaculture
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Tello, Mario, Gonzalez, Alex, Gajardo, Gonzalo, Valdes, Natalia, Vargas, Rodrigo, Rojas, Joselin, and Parra, Mick
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Science / Life Sciences / Biochemistry - Abstract
Aquaculture is a rapidly expanding food production sector, facing the challenge of growth both increasing its efficiency and reducing its negative impact on the environment. Metagenomics is an emerging tool in aquaculture that helps to understand the complex host (fish-shellfish)-microbiota-pathogen-environment relationship underlying disease outbreaks, monitoring the dynamics of microbial diversity in farmed animals subject to different environmental conditions or perturbations. As Chile takes an important share of world aquaculture market, this chapter reviews the actual and potential applications of metagenomics to support a sustainable expansion and diversification of Chilean aquaculture. The focus is on (i) the role and function of the gut microbiota in the proper immunostimulation and disease control and (ii) the role of metagenomics in monitoring environmental microbial biodiversity and dynamics in relation to disease persistence and ecosystem stability. We conclude that despite the importance of the aquaculture sector in Chile, the application of metagenomics to deal with disease control and ecosystem preservation is still an emerging field of study. Understanding host (fish-shellfish)-microbiota-pathogen-environment diversity of interactions in a more holistic view, i.e., the holobiome approach, could be key to develop rational strategies to improve productivity by increasing resistance to diseases and reducing the use of antibiotics and their negative environmental impact.
- Published
- 2019
653. Schwarzian derivatives for pluriharmonic mappings.
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Efraimidis, Iason, Ferrada-Salas, Álvaro, Hernández, Rodrigo, and Vargas, Rodrigo
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A pre-Schwarzian and a Schwarzian derivative for locally univalent pluriharmonic mappings in C n are introduced. Basic properties such as the chain rule, multiplicative invariance and affine invariance are proved for these operators. It is shown that the pre-Schwarzian is stable only with respect to rotations of the identity. A characterization is given for the case when the pre-Schwarzian derivative is holomorphic. Furthermore, it is shown that if the Schwarzian derivative of a pluriharmonic mapping vanishes then the analytic part of this mapping is a Möbius transformation. Some observations are made related to the dilatation of pluriharmonic mappings and to the dilatation of their affine transformations, revealing differences between the theories in the plane and in higher dimensions. An example is given that rules out the possibility for a shear construction theorem to hold in C n , for n ≥ 2. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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654. Carbon dioxide dynamics in a residential lawn of a tropical city.
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Velasco, Erik, Segovia, Elvagris, Choong, Amy M.F., Lim, Benjamin K.Y., and Vargas, Rodrigo
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LAND cover , *CARBON dioxide , *GLOBAL environmental change , *SOIL respiration , *SOIL air , *BIOMASS production - Abstract
Turfgrass is an important component of the urban landscape frequently considered as an alternative land cover to offset anthropogenic CO 2 emissions. However, quantitative information of the potential to directly remove CO 2 from the atmosphere by turfgrass systems is lacking, especially in the tropics. Most assessments have considered the carbon accumulated by grass shoots and soil, but not the release of CO 2 to the atmosphere by soil respiration (i.e., soil CO 2 efflux). Here, we measured at high-temporal resolution (30-min) soil CO 2 efflux, production, and storage rate for nearly three years in a residential lawn of Singapore. Furthermore, we quantified the carbon capture related to biomass production and CO 2 emissions from fossil fuel consumption associated with maintenance activities (e.g., mowing equipment). Warm and humid conditions resulted in relatively constant rates of soil CO 2 efflux, CO 2 storage in soil, and aboveground biomass production (3370, 652, 1671 Mg CO 2 km−2 yr−1; respectively), while the systematic use of mowing machinery emitted 27 Mg CO 2 km−2 yr−1. Soil CO 2 efflux and CO 2 mowing emissions represent carbon losses to the atmosphere, while CO 2 storage in soil and biomass productivity represent gains of carbon into the ecosystem. Under a steady state in which soil CO 2 losses are only compensated by atmospheric CO 2 uptake by photosynthesis, an ideal clipping waste disposal management, in which no CO 2 molecule returns to the atmosphere (i.e., clippings are not burnt), and a 3-week mowing regime, this site can act as a sink of 2296 Mg CO 2 km−2 yr−1. In the scenario of incinerating all clippings, the lawn acts as an emission source of 1046 Mg CO 2 km−2 yr−1. Thus, management practices that reduce mowing frequency together with clipping disposal practices that minimize greenhouse gas emissions are needed to make urban lawns a potential natural solution to mitigate global environmental change. Image 1 • Urban lawns in the tropics can act either as a sink or as an emission source of CO 2. • Belowground carbon accumulation was observed under steady state conditions. • Warm and humid conditions increase biomass production and mowing frequency. • If grass clippings are incinerated, the lawn acts as a net CO 2 emission source. • Locally derived empirical models can be used to account for carbon stocks and fluxes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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655. Utilidad de la tomografía en el diagnóstico y tratamiento de fracturas proximales del humero en tres y cuatro partes en mayores de 65 años
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Sarmiento Velandia, William Giovanni, Blanco Vargas, Edgar, Vargas, Rodrigo, and Morón Duarte, Lina Sofía
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FRACTURA ,Fracture ,Elderly ,ANCIANO ,Fracturas del húmero ,Proximal Humerus ,HUMERO ,Tomografía - Utilización ,treatment ,Fracturas óseas en ancianos - Abstract
Las fracturas proximales del húmero en tres y cuatro partes en mayores de 65 años son un reto diagnóstico y de tratamiento por su complejidad. La clasificación de Neer ha sido una herramienta de ayuda para la caracterización y el tratamiento de las fracturas proximales del húmero y se basa en la evaluación radiográfica la cual puede no dejar claros patrones fractuarios complejos; la tomografía computarizada logra identificar estos patrones complejos los cuales son comunes en pacientes mayores de 65 años, aun así, no es claro el impacto de realizar la tomografía. Este estudio está diseñado para evidenciar si existe un cambio en la clasificación e indicación de manejo en fracturas proximales del húmero en tres y cuatro partes interpretadas con radiografías al ser posteriormente valoradas con tomografía. 15 expertos interpretan e indican manejo de 20 estudios radiográficos de fracturas en tres y cuatro partes del húmero proximal de pacientes mayores de 65 años, previamente asintomáticos, funcionales con única fractura, se realiza la valoración tomográfica y se relaciona a los resultados radiográficos, allí se evidencia si existe o no el cambio de clasificación y manejo de las fracturas. Mediante un estudio observacional, descriptivo y retrospectivo se encuentra que la valoración de la tomografía puede variar la clasificación y el tratamiento indicados inicialmente por los estudios radiográficos en un 60.3% y 54.3% respectivamente, siendo una variación de conducta en más de la mitad de los casos se aprecia la necesidad de realizar el estudio tomográfico. Proximal humeral fractures in three and four parts presented in patients older than 65 years are a diagnostic and therapeutic challenge due to its complexity. Neer classification has been a helpful tool for the characterization and treatment of fractures of the proximal humerus and is based on radiographic evaluation which can not make clear complex fractuares patterns; computed tomography can identify these complex patterns which are common in patients over 65 years, even so, it is not clear the tomography impact. This study is intended to show whether there is a change in the classification and indication of management for fractures in three and four parts of the proximal humerus assessed with radiographs to be subsequently measured with tomography. 15 experts reviewers interpret and indicate treatment of 20 radiographic studies of fractures in three and four parts of the proximal humerus of patients over 65 years, previously asymptomatic, functional with isolated fracture , then the tomographic assessment is conducted and related to radiographic results, then the evidence whether or not there is a change in the classification and management of fractures is seen. Through an observational, descriptive and retrospective study we find that the evaluation of the tomography can vary the classification and treatment initially indicated by radiographic studies in 60.3% and 54.3% respectively, with a variation of conduct in over half of the cases there is seen the need for the tomographic study.
- Published
- 2014
656. El fuero penal militar en la jurisprudencia constitucional colombiana
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Torres Chinchilla, Mauricio, Callejas Bastos, Lina Johanna, and Vargas, Rodrigo
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Delitos relacionados con el servicio ,Jurisprudencia constitucional ,Recomendaciones internacionales ,FUERO MILITAR - DERECHO ,DELITOS - DERECHO ,Fuero penal militar ,DERECHO MILITAR - COLOMBIA - Abstract
El artículo 221 de la Constitución Política de Colombia establece el fuero penal militar, determinando que los miembros de la Fuerza Pública han de ser juzgados por tribunales castrenses cuando cometan delitos relacionados con el servicio y con ocasión al mismo, siendo importante el estudio de los pronunciamientos jurisprudenciales que la Corte Constitucional ha proferido al respecto y las dimensiones que esta figura jurídica ha adquirido con los mismos.
- Published
- 2011
657. La prescripción del seguro de responsabilidad civil en Colombia
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Perico Ramírez, Claudia Liliana, Rodríguez Corci, Luis Eduardo, and Vargas, Rodrigo Ernesto
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SEGURO - DERECHO ,Legislación ,PRESCRIPCION (DERECHO) ,Responsabilidad civil ,Jurisprudencia ,CONTRATOS - SEGUROS ,Patrimonio - Abstract
Establecer si las obligaciones que impone el Código Civil Colombiano a las personas, de responder por los actos propios, indemnizando al que le cause un daño, por la comisión de un acto culposo, se encuentran respaldadas, durante el mismo periodo de exposición patrimonial con que cuenta desde el punto de vista civil el causante de las mismas, por el contrato de seguro de responsabilidad civil, que contrata con una aseguradora para esa finalidad Pregrado
- Published
- 2010
658. Systèmes quantiques d'interactions répétées: l'approche perturbative
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Vargas Le-Bert, Rodrigo, Institut Fourier (IF ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Joseph-Fourier - Grenoble I, Alain Joye, Attal-Claude, Stephane, Institut Fourier (IF), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Vargas, Rodrigo
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Limite de van Hove ,État asymptotique ,États stationnaires hors équilibre ,[MATH] Mathematics [math] ,[MATH]Mathematics [math] ,Systèmes d'interactions répétées - Abstract
Repeated interaction quantum systems are both simple and flexible models which arise naturally in several domains including, particularly, quantum optics and the theory of quantum noises. In this thesis, I became interested in their perturbative study. I generalized a theorem by Attal and Joye [Weak Coupling and Continuous Limits for Repeated Quantum Interactions, J. Stat. Phys., 126, (2007)] on the existence of van Hove limit for those systems to the framework of general von Neumann algebras. Then, I proved that, when the reference system is finite dimensional, the existence of a unique asymptotic state for its van Hove limit implies the convergence of the reference system's state towards a unique periodic asymptotic state, provided that the perturbation parameter is sufficiently small. Moreover, the zero-th order term in a power series expansion on the perturbation parameter of this periodic asymptotic state coincides with the asymptotic state of the van Hove limit, except for their difference in time scale which has to be taken into account (giving rise to the periodicity). This result is important in the physical justification for the use of the thermodynamic formalism in the weak coupling regime developed in [Lebowitz and Spohn, Irreversible thermodynamics for quantum systems weakly coupled to thermal reservoirs, Adv. Chem. Phys. 38 (1978)]., Les systèmes quantiques d'interactions répétées sont des modèles à la fois simples et flexibles qui apparaîssent de façon naturelle dans plusieurs domaines, dont notamment l'optique quantique et la théorie des bruits quantiques. Dans cette thèse, on s'est intéressé à leur étude perturbative. On a généralisé un théorème dû a Attal et Joye [Attal and Joye, Weak Coupling and Continuous Limits for Repeated Quantum Interactions, J. Stat. Phys., 126, (2007)] sur l'existence de limite de van Hove pour ces systèmes au cadre des algèbres de von Neumann quelconques. Ensuite, on a montré que si le système de référence est de dimension fini, alors l'existence d'un état asymptotique unique pour la limite de van Hove implique la convergence vers un état asymptotique périodique unique pour le système de référence, pourvu que le paramètre de perturbation soit suffisamment petit. De plus, le terme d'ordre zéro du développement en puissances du paramètre de perturbation de cet état asymptotique périodique coïncide avec l'état asymptotique de la limite de van Hove, sauf pour la différence d'échelle temporelle qui doit être prise en compte (donnant lieu à la periodicité). Ce résultat est important pour la justification physique de l'utilisation du formalisme thermodynamique dans le régime de couplage faible développé dans [Lebowitz and Spohn, Irreversible thermodynamics for quantum systems weakly coupled to thermal reservoirs, Adv. Chem. Phys. 38 (1978)].
- Published
- 2009
659. Protein-caloric-restriction diet during lactation programs lean phenotype and improves the antioxidative system in adult female rat offspring.
- Author
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Vargas R, Martins IP, Souza ACH, Oliveira JB, Almeira AM, Matiusso CCI, Zara CB, Pavanello A, Rickli S, Neves CQ, Rodrigues WNS, Besson JCF, Becker TCA, Malta A, and Mathias PCF
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- Animals, Female, Rats, Body Weight physiology, Lactation physiology, Diet, Protein-Restricted, Phenotype, Antioxidants metabolism, Rats, Wistar, Caloric Restriction
- Abstract
Nutritional insults early in life, such as during the suckling phase, are associated with phenotypic alterations and promote adverse permanent effects that impair the capacity to maintain energy balance in adulthood. This study aimed to evaluate the long-term effects of a low-protein (LP) diet during lactation on the metabolism and antioxidant systems of adult female rat offspring. Dams were fed a low-protein diet (4% protein) during the first two weeks of lactation or a normal-protein (NP) diet (20% protein) during the entire lactation period. The female offspring received a standard diet throughout the experiment. At 90 days of age, female LP offspring exhibited decreased body weight, feeding efficiency, and fat pad stores. The adult LP female offspring displayed brown adipose tissue hyperplasia without alterations in glucose homeostasis. The LP diet decreased liver triglyceride content and improved the antioxidant system compared to the NP group. The LP diet during the suckling phase promotes a lean phenotype and improves the hepatocyte antioxidant system in adult female offspring. Thus, the LP diet may play an important role in homeostasis and the prevention of metabolic damage.
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- 2024
- Full Text
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660. Worldwide analysis of actionable genomic alterations in lung cancer and targeted pharmacogenomic strategies.
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Echeverría-Garcés G, Ramos-Medina MJ, González A, Vargas R, Cabrera-Andrade A, Armendáriz-Castillo I, García-Cárdenas JM, Ramírez-Sánchez D, Altamirano-Colina A, Echeverría-Espinoza P, Freire MP, Ocaña-Paredes B, Rivera-Orellana S, Guerrero S, Quiñones LA, and López-Cortés A
- Abstract
Based on data from the Global Cancer Statistics 2022, lung cancer stands as the most lethal cancer worldwide, with age-adjusted incidence and mortality rates of 23.6 and 16.9 per 100,000 people, respectively. Despite significant strides in precision oncology driven by large-scale international research consortia, there remains a critical need to deepen our understanding of the genomic landscape across diverse racial and ethnic groups. To address this challenge, we performed comprehensive in silico analyses and data mining to identify pathogenic variants in genes that drive lung cancer. We subsequently calculated the allele frequencies and assessed the deleteriousness of these oncogenic variants among populations such as African, Amish, Ashkenazi Jewish, East and South Asian, Finnish and non-Finnish European, Latino, and Middle Eastern. Our analysis examined 117,707 variants within 86 lung cancer-associated genes across 75,109 human genomes, uncovering 8042 variants that are known or predicted to be pathogenic. We prioritized variants based on their allele frequencies and deleterious scores, and identified those with potential significance for response to anti-cancer therapies through in silico drug simulations, current clinical pharmacogenomic guidelines, and ongoing late-stage clinical trials targeting lung cancer-driving proteins. In conclusion, it is crucial to unite global efforts to create public health policies that emphasize prevention strategies and ensure access to clinical trials, pharmacogenomic testing, and cancer research for these groups in developed nations., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)
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- 2024
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661. Methane fluxes in tidal marshes of the conterminous United States.
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Arias-Ortiz A, Wolfe J, Bridgham SD, Knox S, McNicol G, Needelman BA, Shahan J, Stuart-Haëntjens EJ, Windham-Myers L, Oikawa PY, Baldocchi DD, Caplan JS, Capooci M, Czapla KM, Derby RK, Diefenderfer HL, Forbrich I, Groseclose G, Keller JK, Kelley C, Keshta AE, Kleiner HS, Krauss KW, Lane RR, Mack S, Moseman-Valtierra S, Mozdzer TJ, Mueller P, Neubauer SC, Noyce G, Schäfer KVR, Sanders-DeMott R, Schutte CA, Vargas R, Weston NB, Wilson B, Megonigal JP, and Holmquist JR
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- United States, Temperature, Environmental Monitoring, Seasons, Methane analysis, Methane metabolism, Wetlands, Greenhouse Gases analysis
- Abstract
Methane (CH
4 ) is a potent greenhouse gas (GHG) with atmospheric concentrations that have nearly tripled since pre-industrial times. Wetlands account for a large share of global CH4 emissions, yet the magnitude and factors controlling CH4 fluxes in tidal wetlands remain uncertain. We synthesized CH4 flux data from 100 chamber and 9 eddy covariance (EC) sites across tidal marshes in the conterminous United States to assess controlling factors and improve predictions of CH4 emissions. This effort included creating an open-source database of chamber-based GHG fluxes (https://doi.org/10.25573/serc.14227085). Annual fluxes across chamber and EC sites averaged 26 ± 53 g CH4 m-2 year-1 , with a median of 3.9 g CH4 m-2 year-1 , and only 25% of sites exceeding 18 g CH4 m-2 year-1 . The highest fluxes were observed at fresh-oligohaline sites with daily maximum temperature normals (MATmax) above 25.6°C. These were followed by frequently inundated low and mid-fresh-oligohaline marshes with MATmax ≤25.6°C, and mesohaline sites with MATmax >19°C. Quantile regressions of paired chamber CH4 flux and porewater biogeochemistry revealed that the 90th percentile of fluxes fell below 5 ± 3 nmol m-2 s-1 at sulfate concentrations >4.7 ± 0.6 mM, porewater salinity >21 ± 2 psu, or surface water salinity >15 ± 3 psu. Across sites, salinity was the dominant predictor of annual CH4 fluxes, while within sites, temperature, gross primary productivity (GPP), and tidal height controlled variability at diel and seasonal scales. At the diel scale, GPP preceded temperature in importance for predicting CH4 flux changes, while the opposite was observed at the seasonal scale. Water levels influenced the timing and pathway of diel CH4 fluxes, with pulsed releases of stored CH4 at low to rising tide. This study provides data and methods to improve tidal marsh CH4 emission estimates, support blue carbon assessments, and refine national and global GHG inventories., (© 2024 Smithsonian Institution and The Author(s). Global Change Biology published by John Wiley & Sons Ltd. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)- Published
- 2024
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662. Oral administration of a new copper (I) complex with coumarin as ligand: modulation of the immune response and the composition of the intestinal microbiota in Onchorhynchus mykiss .
- Author
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Parra M, Aldabaldetrecu M, Arce P, Soto-Aguilera S, Vargas R, Guerrero J, Tello M, and Modak B
- Abstract
[Cu(NN
1 )2 ]ClO4 is a copper (I) complex, where NN1 is an imine ligand 6-((quinolin-2-ylmethylene) amino)-2H-chromen-2-one obtained by derivatization of natural compound coumarin, developed for the treatment of infectious diseases that affect salmonids. In previous research, we showed that the Cu(I) coordination complex possesses antibacterial activity against Flavobacterium psychrophilum , providing protection against this pathogen in rainbow trout during challenge assays (with an RPS of 50%). In the present study, the effects of administering [Cu(NN1 )2 ]ClO4 to Oncorhynchus mykiss over a 60-days period were evaluated with regard to systemic immune response and its potential to alter intestinal microbiota composition. In O. mykiss , an immunostimulatory effect was evident at days 30 and 45 after administration, resulting in an increment of transcript levels of IFN-γ, IL-12, TNF-α, lysozyme and perforin. To determine whether these immunomodulatory effects correlated with changes in the intestinal microbiota, we analyzed the metagenome diversity by V4 16S rRNA sequencing. In O. mykiss , both [Cu(NN1 )2 ]ClO4 and commercial antibiotic florfenicol had comparable effects at the phylum level, resulting in a predominance of proteobacteria and firmicutes. Nonetheless, at the genus level, florfenicol and [Cu(NN1 )2 ]ClO4 complex exhibited distinct effects on the intestinal microbiota of O. mykiss . In conclusion, our findings demonstrate that [Cu(NN1 )2 ]ClO4 is capable of stimulating the immune system at a systemic level, while inducing alterations in the composition of the intestinal microbiota in O. mykiss ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Parra, Aldabaldetrecu, Arce, Soto-Aguilera, Vargas, Guerrero, Tello and Modak.)- Published
- 2024
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663. Gastric cancer actionable genomic alterations across diverse populations worldwide and pharmacogenomics strategies based on precision oncology.
- Author
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Echeverría-Garcés G, Ramos-Medina MJ, Vargas R, Cabrera-Andrade A, Altamirano-Colina A, Freire MP, Montalvo-Guerrero J, Rivera-Orellana S, Echeverría-Espinoza P, Quiñones LA, and López-Cortés A
- Abstract
Introduction: Gastric cancer is one of the most prevalent types of cancer worldwide. The World Health Organization (WHO), the International Agency for Research on Cancer (IARC), and the Global Cancer Statistics (GLOBOCAN) reported an age standardized global incidence rate of 9.2 per 100,000 individuals for gastric cancer in 2022, with a mortality rate of 6.1. Despite considerable progress in precision oncology through the efforts of international consortia, understanding the genomic features and their influence on the effectiveness of anti-cancer treatments across diverse ethnic groups remains essential. Methods: Our study aimed to address this need by conducting integrated in silico analyses to identify actionable genomic alterations in gastric cancer driver genes, assess their impact using deleteriousness scores, and determine allele frequencies across nine global populations: European Finnish, European non-Finnish, Latino, East Asian, South Asian, African, Middle Eastern, Ashkenazi Jewish, and Amish. Furthermore, our goal was to prioritize targeted therapeutic strategies based on pharmacogenomics clinical guidelines, in silico drug prescriptions, and clinical trial data. Results: Our comprehensive analysis examined 275,634 variants within 60 gastric cancer driver genes from 730,947 exome sequences and 76,215 whole-genome sequences from unrelated individuals, identifying 13,542 annotated and predicted oncogenic variants. We prioritized the most prevalent and deleterious oncogenic variants for subsequent pharmacogenomics testing. Additionally, we discovered actionable genomic alterations in the ARID1A, ATM, BCOR, ERBB2, ERBB3, CDKN2A, KIT, PIK3CA, PTEN, NTRK3, TP53 , and CDKN2A genes that could enhance the efficacy of anti-cancer therapies, as suggested by in silico drug prescription analyses, reviews of current pharmacogenomics clinical guidelines, and evaluations of phase III and IV clinical trials targeting gastric cancer driver proteins. Discussion: These findings underline the urgency of consolidating efforts to devise effective prevention measures, invest in genomic profiling for underrepresented populations, and ensure the inclusion of ethnic minorities in future clinical trials and cancer research in developed countries., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Echeverría-Garcés, Ramos-Medina, Vargas, Cabrera-Andrade, Altamirano-Colina, Freire, Montalvo-Guerrero, Rivera-Orellana, Echeverría-Espinoza, Quiñones and López-Cortés.)
- Published
- 2024
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664. Importance of Probiotics in Fish Aquaculture: Towards the Identification and Design of Novel Probiotics.
- Author
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Torres-Maravilla E, Parra M, Maisey K, Vargas RA, Cabezas-Cruz A, Gonzalez A, Tello M, and Bermúdez-Humarán LG
- Abstract
Aquaculture is a growing industry worldwide, but it faces challenges related to animal health. These challenges include infections by parasites, bacteria, and viral pathogens. These harmful pathogens have devastating effects on the industry, despite efforts to control them through vaccination and antimicrobial treatments. Unfortunately, these measures have proven insufficient to address the sanitary problems, resulting in greater environmental impact due to the excessive use of antimicrobials. In recent years, probiotics have emerged as a promising solution to enhance the performance of the immune system against parasitic, bacterial, and viral pathogens in various species, including mammals, birds, and fish. Some probiotics have been genetically engineered to express and deliver immunomodulatory molecules. These promote selective therapeutic effects and specific immunization against specific pathogens. This review aims to summarize recent research on the use of probiotics in fish aquaculture, with a particular emphasis on genetically modified probiotics. In particular, we focus on the advantages of using these microorganisms and highlight the main barriers hindering their widespread application in the aquaculture industry.
- Published
- 2024
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665. Microfilariae infection by Acanthocheilonema reconditum and Dirofilaria immitis and their molecular detection in a dog with lymphoma: Case report.
- Author
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Lugo-Vargas R, Perez-Ramirez RD, Carrillo-Godoy N, and Rondón-Barragán IS
- Abstract
Objective: Microfilariae parasites are common in tropical regions, and some species are reported as potentially zoonotic. The diagnosis of filarial infection in dogs by cytology or hematologic techniques showed lower sensibility and specificity, which may result in misdiagnosis. Thus, molecular techniques seem to be an alternative to identifying and detecting microfilariae infections. On the other hand, lymphoma is one of the main tumors in domestic animals, with a high prevalence in domestic canines. This study aims to report a mixed infection with microfilariae in a dog with lymphoma, emphasizing its diagnosis and the possible role of this infection in the development of the neoplasia., Materials and Methods: An 8-year-old male mixed breed dog was referred to consultation due to the presence of lethargy, recumbency, skin ulceration lesions, nonspecific pain manifestations, emesis, myoclonus in the left temporalis muscle, and seizures. Routine blood and biochemistry tests were normal, and cytology of the skin evidenced a microfilariae infection. The dog died due to a cardiorespiratory arrest, and tissue sampling was done for histopathology and molecular analysis at the necropsy examination., Results: Skin lesions were related to a microfilarial pyogranuloma related to Acanthocheilonema reconditum . Histopathology of the spleen and liver revealed a diffuse lymphoma composed of blast cells and large lymphocytes, distributed diffusely in the parenchyma and surrounding the vasculature. In the skin, microfilariae were seen in some superficial capillaries., Conclusion: This study describes a microfilariae mixed infection with A. reconditum and Dirofilaria immitis in a dog with a lymphoma and its molecular detection. To the knowledge of the authors, this is the first report of a mixed microfilariae infection in a tumor of a dog and highlights the use of molecular techniques, i.e., polymerase chain reaction, for an accurate diagnosis., Competing Interests: The authors declare that there is no conflict of interest., (Copyright: © Journal of Advanced Veterinary and Animal Research.)
- Published
- 2023
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666. An updated examination of the perception of barriers for pharmacogenomics implementation and the usefulness of drug/gene pairs in Latin America and the Caribbean.
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Salas-Hernández A, Galleguillos M, Carrasco M, López-Cortés A, Redal MA, Fonseca-Mendoza D, Esperón P, González-Martínez F, Lares-Asseff I, Lazarowski A, Loera-Castañeda V, Remírez D, Martínez MF, Vargas R, Rios-Santos F, Macho A, Cayún JP, Perez GR, Gutierrez C, Cerpa LC, Leiva T, Calfunao S, Xajil L, Sandoval C, Suárez M, Gonzalez A, Echeverría-Garcés G, Sullón-Dextre L, Cordero-García E, Morales AR, Avendaño A, Sánchez E, Bastone LC, Lara C, Zuluaga-Arias P, Soler AM, Da Luz J, Burgueño-Rodríguez G, Vital M, Reyes-Reyes E, Huaccha A, Ariza YV, Tzul N, Rendón AL, Serrano R, Acosta L, Motta-Pardo A, Beltrán-Angarita L, Brand E, Jiménez MA, Hidalgo-Lozada GM, Romero-Prado MMJ, Escobar-Castro K, Umaña-Rivas M, Vivas JD, Lagos P, Martínez YB, Quesada S, Calfio C, Arias ML, Lavanderos MA, Cáceres DD, Salazar-Granara A, Varela NM, and Quiñones LA
- Abstract
Pharmacogenomics (PGx) is considered an emergent field in developing countries. Research on PGx in the Latin American and the Caribbean (LAC) region remains scarce, with limited information in some populations. Thus, extrapolations are complicated, especially in mixed populations. In this paper, we reviewed and analyzed pharmacogenomic knowledge among the LAC scientific and clinical community and examined barriers to clinical application. We performed a search for publications and clinical trials in the field worldwide and evaluated the contribution of LAC. Next, we conducted a regional structured survey that evaluated a list of 14 potential barriers to the clinical implementation of biomarkers based on their importance. In addition, a paired list of 54 genes/drugs was analyzed to determine an association between biomarkers and response to genomic medicine. This survey was compared to a previous survey performed in 2014 to assess progress in the region. The search results indicated that Latin American and Caribbean countries have contributed 3.44% of the total publications and 2.45% of the PGx-related clinical trials worldwide thus far. A total of 106 professionals from 17 countries answered the survey. Six major groups of barriers were identified. Despite the region's continuous efforts in the last decade, the primary barrier to PGx implementation in LAC remains the same, the "need for guidelines, processes, and protocols for the clinical application of pharmacogenetics/pharmacogenomics". Cost-effectiveness issues are considered critical factors in the region. Items related to the reluctance of clinicians are currently less relevant. Based on the survey results, the highest ranked (96%-99%) gene/drug pairs perceived as important were CYP2D6 /tamoxifen, CYP3A5 /tacrolimus, CYP2D6 /opioids, DPYD /fluoropyrimidines, TMPT /thiopurines, CYP2D6 /tricyclic antidepressants, CYP2C19 /tricyclic antidepressants, NUDT15 /thiopurines, CYP2B6 /efavirenz, and CYP2C19 /clopidogrel. In conclusion, although the global contribution of LAC countries remains low in the PGx field, a relevant improvement has been observed in the region. The perception of the usefulness of PGx tests in biomedical community has drastically changed, raising awareness among physicians, which suggests a promising future in the clinical applications of PGx in LAC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Salas-Hernández, Galleguillos, Carrasco, López-Cortés, Redal, Fonseca-Mendoza, Esperón, González-Martínez, Lares-Asseff, Lazarowski, Loera-Castañeda, Remírez, Martínez, Vargas, Rios-Santos, Macho, Cayún, Perez, Gutierrez, Cerpa, Leiva, Calfunao, Xajil, Sandoval, Suárez, Gonzalez, Echeverría-Garcés, Sullón-Dextre, Cordero-García, Morales, Avendaño, Sánchez, Bastone, Lara, Zuluaga-Arias, Soler, Da Luz, Burgueño-Rodríguez, Vital, Reyes-Reyes, Huaccha, Ariza, Tzul, Rendón, Serrano, Acosta, Motta-Pardo, Beltrán-Angarita, Brand, Jiménez, Hidalgo-Lozada, Romero-Prado, Escobar-Castro, Umaña-Rivas, Vivas, Lagos, Martínez, Quesada, Calfio, Arias, Lavanderos, Cáceres, Salazar-Granara, Varela and Quiñones.)
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- 2023
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667. Protein-caloric restriction induced HPA axis activation and altered the milk composition imprint metabolism of weaned rat offspring.
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Martins IP, Vargas R, Saavedra LPJ, Rickli S, Matiusso CCI, Pavanello A, Casagrande L, Pastre MJ, Oliveira JB, de Almeida AM, de Souza ACH, de Oliveira JC, Malta A, and Mathias PCF
- Subjects
- Female, Rats, Animals, Male, Humans, Caloric Restriction, Hypothalamo-Hypophyseal System, Corticosterone, Pituitary-Adrenal System, Lactation physiology, Proteins metabolism, Adipose Tissue, Brown metabolism, Maternal Nutritional Physiological Phenomena, Milk, Obesity metabolism
- Abstract
Objectives: Maternal protein-caloric restriction during lactation can malprogram offspring into having a lean phenotype associated with metabolic dysfunction in early life and adulthood. The aim of this study was to investigate the relationships between nutritional stress, maternal behavior and metabolism, milk composition, and offspring parameters. Additionally, we focused on the role of hypothalamus-pituitary-adrenal axis hyperactivation during lactation., Methods: Dams were fed a low-protein diet (4% protein) during the first 2 wk of lactation or a normal-protein diet (20% protein) during all lactation. Analyses of dams, milk, and offspring were conducted on postnatal days (PD) 7, 14, and 21., Results: Body weight and food intake decreased in dams, which was associated with reduced fat pad stores and increased corticosterone levels at PD 14. The stressed low-protein diet dams demonstrated alterations in behavior and offspring care. Despite nutritional deprivation, dams adapted their metabolism to provide adequate energy supply through milk; however, we demonstrated elevated corticosterone and total fat levels in milk at PD 14. Male offspring also showed increased corticosterone at PD 7, associated with a lean phenotype and alterations in white and brown adipose tissue morphology at PD 21., Conclusion: Exposure to protein-caloric restriction diet of dams during lactation increased the glucocorticoid levels in dams, milk, and offspring, which is associated with alterations in maternal behavior and milk composition. Thus, glucocorticoids and milk composition may play an important role in metabolic programming induced by maternal undernutrition., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2023
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668. Analysis of microbiota-host communication mediated by butyrate in Atlantic salmon.
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Vargas RA, Soto-Aguilera S, Parra M, Herrera S, Santibañez A, Kossack C, Saavedra CP, Mora O, Pineda M, Gonzalez O, Gonzalez A, Maisey K, Torres-Maravilla E, Bermúdez-Humarán LG, Suárez-Villota EY, and Tello M
- Abstract
Butyrate is a microbiota-produced metabolite, sensed by host short-chain fatty acid receptors FFAR2 (Gpr43), FFAR3 (Gpr41), HCAR2 (Gpr109A), and Histone deacetylase (HDAC) that promotes microbiota-host crosstalk. Butyrate influences energy uptake, developmental and immune response in mammals. This microbial metabolite is produced by around 79 anaerobic genera present in the mammalian gut, yet little is known about the role of butyrate in the host-microbiota interaction in salmonid fish. To further our knowledge of this interaction, we analyzed the intestinal microbiota and genome of Atlantic salmon ( Salmo salar ), searching for butyrate-producing genera and host butyrate receptors. We identified Firmicutes, Proteobacteria, and Actinobacteria as the main butyrate-producing bacteria in the salmon gut microbiota. In the Atlantic salmon genome, we identified an expansion of genes orthologous to FFAR2 and HCAR2 receptors, and class I and IIa HDACs that are sensitive to butyrate. In addition, we determined the expression levels of orthologous of HCAR2 in the gut, spleen, and head-kidney, and FFAR2 in RTgutGC cells. The effect of butyrate on the Atlantic salmon immune response was evaluated by analyzing the pro and anti-inflammatory cytokines response in vitro in SHK-1 cells by RT-qPCR. Butyrate decreased the expression of the pro-inflammatory cytokine IL-1β and increased anti-inflammatory IL-10 and TGF-β cytokines. Butyrate also reduced the expression of interferon-alpha, Mx, and PKR, and decreased the viral load at a higher concentration (4 mM) in cells treated with this molecule before the infection with Infectious Pancreatic Necrosis Virus (IPNV) by mechanisms independent of FFAR2, FFAR3 and HCAR2 expression that probably inhibit HDAC. Moreover, butyrate modified phosphorylation of cytoplasmic proteins in RTgutGC cells. Our data allow us to infer that Atlantic salmon have the ability to sense butyrate produced by their gut microbiota via different specific targets, through which butyrate modulates the immune response of pro and anti-inflammatory cytokines and the antiviral response., Competing Interests: “The authors declare no conflict of interest.” “The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results”., (© 2023 The Authors.)
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- 2023
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669. Protein restriction during lactation causes transgenerational metabolic dysfunction in adult rat offspring.
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Vargas R, Martins IP, Matiusso CCI, Casagrande RA, Zara CB, Huppes de Souza AC, Horst WP, Sieklicki TC, Becker TCA, Lucredi NC, Comar JF, Malta A, and Mathias PCF
- Abstract
Introduction: Protein restriction during lactation can induce metabolic dysfunctions and has a huge impact on the offspring's phenotype later in its life. We tested whether the effects of a maternal low-protein diet (LP) in rats can be transmitted to the F2 generation and increase their vulnerability to dietary insults in adulthood., Methods: Female Wistar rats (F0) were fed either a low-protein diet (LP; 4% protein) during the first 2 weeks of lactation or a normal-protein diet (NP; 23% protein). The female offspring (F1 generation) were maintained on a standard diet throughout the experiment. Once adulthood was reached, female F1 offspring from both groups (i.e., NP-F1 and LP-F1) were bred to proven males, outside the experiment, to produce the F2 generation. Male F2 offspring from both groups (NP-F2 and LP-F2 groups) received a standard diet until 60 days old, at which point they received either a normal fat (NF; 4.5% fat) or a high fat diet (HF; 35% fat) for 30 days., Results: At 90 days old, LPNF-F2 offspring had increased lipogenesis and fasting insulinemia compared to NPNF-F2, without alteration in insulin sensitivity. HF diet caused increased gluconeogenesis and displayed glucose intolerance in LPHF-F2 offspring compared to LPNF-F2 offspring. Additionally, the HF diet led to damage to lipid metabolism (such as steatosis grade 3), higher body weight, fat pad stores, and hepatic lipid content., Discussion: We concluded that an F0 maternal protein restricted diet during lactation can induce a transgenerational effect on glucose and liver metabolism in the F2 generation, making the offspring's liver more vulnerable to nutritional injury later in life., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Vargas, Martins, Matiusso, Casagrande, Zara, Huppes de Souza, Horst, Sieklicki, Becker, Lucredi, Comar, Malta and Mathias.)
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- 2023
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670. First study on microscopic and molecular detection of Acanthocheilonema reconditum and Leishmania infantum coinfection in dogs in Southwest Colombia.
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Pérez-Ramírez RD, Lugo-Vargas R, Petano-Duque JM, Cruz-Méndez JS, and Rondón-Barragán IS
- Abstract
Background and Aim: Canine vector-borne diseases represent an important issue for the welfare and health of animals, but also have great zoonotic potential. These diseases are caused by bacteria, nematodes such as filariae, and other parasites such as Leishmania spp. Given the difficulty in differentiating common microfilariae in dogs by microscopy and serological methods, molecular techniques such as polymerase chain reaction (PCR) and sequencing should be valuable for reaching a reliable diagnosis. This study aimed to use microscopy and PCR to identify the microfilarial species in dogs from Valle del Cauca, Colombia, and a possible association with Leishmania infantum parasites., Materials and Methods: This study was conducted on 270 dogs from Pradera and Florida municipalities. Microfilariae were detected in dogs by optical microscopy and amplification with 5.8S-ITS2-28S . Species identification was achieved through the amplification of the gene cytochrome oxidase I ( COX1 )., Results: Microscopic detection of microfilariae was possible in 4.81% (13/270) of the dogs. In addition, by PCR of COX1 and Sanger sequencing of ITS2 , Acanthocheilonema reconditum was identified as the circulating microfilarial species in 12 dogs, coinfecting with the species L. infantum ( Leishmania donovani complex)., Conclusion: To the best of our knowledge, this is the first report on A. reconditum and L. infantum mixed infection in dogs in Colombia, particularly in the Valle del Cauca., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Pérez-Ramírez, et al.)
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- 2023
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671. Practical Guide to Measuring Wetland Carbon Pools and Fluxes.
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Bansal S, Creed IF, Tangen BA, Bridgham SD, Desai AR, Krauss KW, Neubauer SC, Noe GB, Rosenberry DO, Trettin C, Wickland KP, Allen ST, Arias-Ortiz A, Armitage AR, Baldocchi D, Banerjee K, Bastviken D, Berg P, Bogard MJ, Chow AT, Conner WH, Craft C, Creamer C, DelSontro T, Duberstein JA, Eagle M, Fennessy MS, Finkelstein SA, Göckede M, Grunwald S, Halabisky M, Herbert E, Jahangir MMR, Johnson OF, Jones MC, Kelleway JJ, Knox S, Kroeger KD, Kuehn KA, Lobb D, Loder AL, Ma S, Maher DT, McNicol G, Meier J, Middleton BA, Mills C, Mistry P, Mitra A, Mobilian C, Nahlik AM, Newman S, O'Connell JL, Oikawa P, van der Burg MP, Schutte CA, Song C, Stagg CL, Turner J, Vargas R, Waldrop MP, Wallin MB, Wang ZA, Ward EJ, Willard DA, Yarwood S, and Zhu X
- Abstract
Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions., Supplementary Information: The online version contains supplementary material available at 10.1007/s13157-023-01722-2., Competing Interests: Competing InterestsThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© The Author(s) 2023.)
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- 2023
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672. Exposure to glyphosate-based herbicide during early stages of development increases insulin sensitivity and causes liver inflammation in adult mice offspring.
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Gomes ECZ, Teleken JL, Vargas R, Alegre-Maller ACP, Amorim JPA, Bonfleur ML, and Balbo SL
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- Animals, Female, Glucose metabolism, Glycine analogs & derivatives, Humans, Inflammation chemically induced, Insulin, Liver metabolism, Mice, Pregnancy, Rats, Rats, Wistar, Glyphosate, Herbicides metabolism, Herbicides toxicity, Insulin Resistance, Prenatal Exposure Delayed Effects chemically induced, Prenatal Exposure Delayed Effects metabolism
- Abstract
Objective: To investigate the effect of pre and postnatal exposure to a glyphosate-based herbicide on glucose metabolism and liver histology in adult F1 mice offspring., Methods: Female mice (C57Bl/6) received 0.5% of glyphosate (Roundup Original DI®) in drinking water or purified water (Glyphosate Group and Control Group respectively) during pregnancy and lactation. Offspring (F1) were submitted to glucose and insulin tolerance tests and euthanized on postnatal day 150. Body and plasma parameters, and liver histology were analyzed., Results: Exposure to glyphosate reduced maternal body weight gain during pregnancy and lactation, with no impacts on litter size. Pre and postnatal exposure to glyphosate did not affect body parameters but increased glucose tolerance on postnatal day 60. In spite of glucose tolerance normalization by postnatal day 143, this effect was associated with higher insulin sensitivity relative to mice in the Control-F1 Group. Mice in the Glyphosate-F1 Group had mild and moderate lobular inflammation in the liver., Conclusion: Maternal exposure to glyphosate affected insulin sensitivity and caused hepatic inflammation in adult F1 mice offspring.
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- 2022
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673. Historically inconsistent productivity and respiration fluxes in the global terrestrial carbon cycle.
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Jian J, Bailey V, Dorheim K, Konings AG, Hao D, Shiklomanov AN, Snyder A, Steele M, Teramoto M, Vargas R, and Bond-Lamberty B
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- Carbon, Carbon Dioxide, Respiration, Carbon Cycle, Climate Change
- Abstract
The terrestrial carbon cycle is a major source of uncertainty in climate projections. Its dominant fluxes, gross primary productivity (GPP), and respiration (in particular soil respiration, R
S ), are typically estimated from independent satellite-driven models and upscaled in situ measurements, respectively. We combine carbon-cycle flux estimates and partitioning coefficients to show that historical estimates of global GPP and RS are irreconcilable. When we estimate GPP based on RS measurements and some assumptions about RS :GPP ratios, we found the resulted global GPP values (bootstrap mean [Formula: see text] Pg C yr-1 ) are significantly higher than most GPP estimates reported in the literature ([Formula: see text] Pg C yr-1 ). Similarly, historical GPP estimates imply a soil respiration flux (RsGPP , bootstrap mean of [Formula: see text] Pg C yr-1 ) statistically inconsistent with most published RS values ([Formula: see text] Pg C yr-1 ), although recent, higher, GPP estimates are narrowing this gap. Furthermore, global RS :GPP ratios are inconsistent with spatial averages of this ratio calculated from individual sites as well as CMIP6 model results. This discrepancy has implications for our understanding of carbon turnover times and the terrestrial sensitivity to climate change. Future efforts should reconcile the discrepancies associated with calculations for GPP and Rs to improve estimates of the global carbon budget., (© 2022. The Author(s).)- Published
- 2022
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674. Spatiotemporal variability and origin of CO 2 and CH 4 tree stem fluxes in an upland forest.
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Barba J, Poyatos R, Capooci M, and Vargas R
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- Carbon Dioxide, Forests, Methane, Nitrous Oxide, Soil, Ecosystem, Trees
- Abstract
The exchange of multiple greenhouse gases (i.e., CO
2 and CH4 ) between tree stems and the atmosphere represents a knowledge gap in the global carbon cycle. Stem CO2 and CH4 fluxes vary across time and space and are unclear, which are their individual or shared drivers. Here we measured CO2 and CH4 fluxes at different stem heights combining manual (biweekly; n = 678) and automated (hourly; n > 38,000) measurements in a temperate upland forest. All trees showed CO2 and CH4 emissions despite 20% of measurements showing net CH4 uptake. Stem CO2 fluxes presented clear seasonal trends from manual and automated measurements. Only automated measurements captured the high temporal variability of stem CH4 fluxes revealing clear seasonal trends. Despite that temporal integration, the limited number of automated chambers made stand-level mean CH4 fluxes sensitive to "hot spots," resulting in mean fluxes with high uncertainty. Manual measurements provided better integration of spatial variability, but their lack of temporal variability integration hindered the detection of temporal trends and stand-level mean fluxes. These results highlight the potential bias of previous studies of stem CH4 fluxes solely based on manual or automated measurements. Stem height, temperature, and soil moisture only explained 7% and 11% of the stem CH4 flux variability compared to 42% and 81% for CO2 (manual and automated measurements, respectively). This large unexplained variability, in combination with high CH4 concentrations in the trees' heartwood, suggests that stem CH4 fluxes might be more influenced by gas transport and diffusivity through the wood than by drivers of respiratory CO2 flux, which has crucial implications for developing process-based ecosystem models. We postulate that CH4 is likely originated within tree stems because of lack of a consistent vertical pattern in CH4 fluxes, evidence of CH4 production in wood incubations, and low CH4 concentration in the soil profile but high concentrations within the trees' heartwood., (© 2021 John Wiley & Sons Ltd.)- Published
- 2021
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675. High light and temperature reduce photosynthetic efficiency through different mechanisms in the C 4 model Setaria viridis.
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Anderson CM, Mattoon EM, Zhang N, Becker E, McHargue W, Yang J, Patel D, Dautermann O, McAdam SAM, Tarin T, Pathak S, Avenson TJ, Berry J, Braud M, Niyogi KK, Wilson M, Nusinow DA, Vargas R, Czymmek KJ, Eveland AL, and Zhang R
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- Carbon metabolism, Setaria Plant radiation effects, Hot Temperature adverse effects, Light adverse effects, Photosynthesis radiation effects, Setaria Plant metabolism, Transcriptome radiation effects
- Abstract
C
4 plants frequently experience high light and high temperature conditions in the field, which reduce growth and yield. However, the mechanisms underlying these stress responses in C4 plants have been under-explored, especially the coordination between mesophyll (M) and bundle sheath (BS) cells. We investigated how the C4 model plant Setaria viridis responded to a four-hour high light or high temperature treatment at photosynthetic, transcriptomic, and ultrastructural levels. Although we observed a comparable reduction of photosynthetic efficiency in high light or high temperature treated leaves, detailed analysis of multi-level responses revealed important differences in key pathways and M/BS specificity responding to high light and high temperature. We provide a systematic analysis of high light and high temperature responses in S. viridis, reveal different acclimation strategies to these two stresses in C4 plants, discover unique light/temperature responses in C4 plants in comparison to C3 plants, and identify potential targets to improve abiotic stress tolerance in C4 crops., (© 2021. The Author(s).)- Published
- 2021
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676. Lactococcus lactis Expressing Type I Interferon From Atlantic Salmon Enhances the Innate Antiviral Immune Response In Vivo and In Vitro .
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Muñoz C, González-Lorca J, Parra M, Soto S, Valdes N, Sandino AM, Vargas R, González A, and Tello M
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- Animals, Birnaviridae Infections immunology, Birnaviridae Infections microbiology, Birnaviridae Infections virology, Cell Line, Fish Proteins genetics, Fisheries, Host-Pathogen Interactions, Infectious pancreatic necrosis virus growth & development, Infectious pancreatic necrosis virus immunology, Interferon Type I genetics, Lactococcus lactis genetics, Lactococcus lactis immunology, Myxovirus Resistance Proteins metabolism, Salmo salar genetics, Salmo salar immunology, Salmo salar virology, Viral Load, eIF-2 Kinase metabolism, Birnaviridae Infections prevention & control, Fish Proteins metabolism, Immunity, Innate, Infectious pancreatic necrosis virus pathogenicity, Interferon Type I metabolism, Lactococcus lactis metabolism, Probiotics, Salmo salar microbiology
- Abstract
In salmon farming, viruses are responsible for outbreaks that produce significant economic losses for which there is a lack of control tools other than vaccines. Type I interferon has been successfully used for treating some chronic viral infections in humans. However, its application in salmonids depends on the proper design of a vehicle that allows its massive administration, ideally orally. In mammals, administration of recombinant probiotics capable of expressing cytokines has shown local and systemic therapeutic effects. In this work, we evaluate the use of Lactococcus lactis as a type I Interferon expression system in Atlantic salmon, and we analyze its ability to stimulate the antiviral immune response against IPNV, in vivo and in vitro . The interferon expressed in L. lactis , even though it was located mainly in the bacterial cytoplasm, was functional, stimulating Mx and PKR expression in CHSE-214 cells, and reducing the IPNV viral load in SHK-1 cells. In vivo , the oral administration of this L. lactis producer of Interferon I increases Mx and PKR expression, mainly in the spleen, and to a lesser extent, in the head kidney. The oral administration of this strain also reduces the IPNV viral load in Atlantic salmon specimens challenged with this pathogen. Our results show that oral administration of L. lactis producing Interferon I induces systemic effects in Atlantic salmon, allowing to stimulate the antiviral immune response. This probiotic could have effects against a wide variety of viruses that infect Atlantic salmon and also be effective in other salmonids due to the high identity among their type I interferons., Competing Interests: Authors MT and AS were employed by the company IctioBiotic SpA and ActivaQ S.A., respectively. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Muñoz, González-Lorca, Parra, Soto, Valdes, Sandino, Vargas, González and Tello.)
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- 2021
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677. Oral Administration of Lactococcus lactis Producing Interferon Type II, Enhances the Immune Response Against Bacterial Pathogens in Rainbow Trout.
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Santibañez A, Paine D, Parra M, Muñoz C, Valdes N, Zapata C, Vargas R, Gonzalez A, and Tello M
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- Administration, Oral, Animals, Cell Line, Fish Proteins genetics, Fish Proteins immunology, Flavobacteriaceae Infections immunology, Flavobacteriaceae Infections metabolism, Flavobacteriaceae Infections microbiology, Flavobacterium immunology, Host-Pathogen Interactions, Interferon-gamma genetics, Interferon-gamma immunology, Interleukin-12 metabolism, Interleukin-6 metabolism, Lactococcus lactis genetics, Lactococcus lactis immunology, Oncorhynchus mykiss genetics, Oncorhynchus mykiss immunology, Oncorhynchus mykiss metabolism, Phylogeny, Fish Proteins metabolism, Flavobacteriaceae Infections prevention & control, Flavobacterium pathogenicity, Interferon-gamma metabolism, Lactococcus lactis metabolism, Oncorhynchus mykiss microbiology, Probiotics administration & dosage
- Abstract
Lactic acid bacteria are a powerful vehicle for releasing of cytokines and immunostimulant peptides at the gastrointestinal level after oral administration. However, its therapeutic application against pathogens that affect rainbow trout and Atlantic salmon has been little explored. Type II interferon in Atlantic salmon activates the antiviral response, protecting against viral infection, but its role against bacterial infection has not been tested in vivo. In this work, through the design of a recombinant lactic acid bacterium capable of producing Interferon gamma from Atlantic salmon, we explore its role against bacterial infection and the ability to stimulate systemic immune response after oral administration of the recombinant probiotic. Recombinant interferon was active in vitro , mainly stimulating IL-6 expression in SHK-1 cells. In vivo , oral administration of the recombinant probiotic produced an increase in IL-6, IFNγ and IL-12 in the spleen and kidney, in addition to stimulating the activity of lysozyme in serum. The challenge trials indicated that the administration of the IFNγ-producing probiotic doubled the survival in fish infected with F. psychrophilum . In conclusion, our results showed that the oral administration of lactic acid bacteria producing IFNγ managed to stimulate the immune response at a systemic level, conferring protection against pathogens, showing a biotechnological potential for its application in aquaculture., Competing Interests: Author MT was employed by company Ictio Biotechnologies SA. The authors declare that the research carried out as well as the results present in this work have been in common agreement with Ictio Biotechnologies SA and the licensee Ictiobiotic SpA. Part of these results have been included in the patent application number 2897-2017 requested in the Chilean industrial property registry (INAPI). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Santibañez, Paine, Parra, Muñoz, Valdes, Zapata, Vargas, Gonzalez and Tello.)
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- 2021
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678. Substantial hysteresis in emergent temperature sensitivity of global wetland CH 4 emissions.
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Chang KY, Riley WJ, Knox SH, Jackson RB, McNicol G, Poulter B, Aurela M, Baldocchi D, Bansal S, Bohrer G, Campbell DI, Cescatti A, Chu H, Delwiche KB, Desai AR, Euskirchen E, Friborg T, Goeckede M, Helbig M, Hemes KS, Hirano T, Iwata H, Kang M, Keenan T, Krauss KW, Lohila A, Mammarella I, Mitra B, Miyata A, Nilsson MB, Noormets A, Oechel WC, Papale D, Peichl M, Reba ML, Rinne J, Runkle BRK, Ryu Y, Sachs T, Schäfer KVR, Schmid HP, Shurpali N, Sonnentag O, Tang ACI, Torn MS, Trotta C, Tuittila ES, Ueyama M, Vargas R, Vesala T, Windham-Myers L, Zhang Z, and Zona D
- Abstract
Wetland methane (CH
4 ) emissions ([Formula: see text]) are important in global carbon budgets and climate change assessments. Currently, [Formula: see text] projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent [Formula: see text] temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that [Formula: see text] are often controlled by factors beyond temperature. Here, we evaluate the relationship between [Formula: see text] and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between [Formula: see text] and temperature, suggesting larger [Formula: see text] sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.- Published
- 2021
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679. Amplicon of 16S rRNA Gene Sequencing of Fertilized Volcanic Soils from Southern Chile.
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Vargas RA, Valdés N, Balic I, Contreras EI, Venegas C, Aranada CP, Tello M, and Gonzalez AR
- Abstract
The volcanic soils of Chiloé Island, Chile, have physical and chemical characteristics that affect their productivity. We report here a 16S rRNA gene analysis that characterizes the predominant microbial communities in volcanic soils of Chiloé either in the presence or absence of fertilization. The major phyla identified were Proteobacteria , Acidobacteria , and Actinobacteria ., (Copyright © 2021 Vargas et al.)
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- 2021
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680. COSORE: A community database for continuous soil respiration and other soil-atmosphere greenhouse gas flux data.
- Author
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Bond-Lamberty B, Christianson DS, Malhotra A, Pennington SC, Sihi D, AghaKouchak A, Anjileli H, Altaf Arain M, Armesto JJ, Ashraf S, Ataka M, Baldocchi D, Andrew Black T, Buchmann N, Carbone MS, Chang SC, Crill P, Curtis PS, Davidson EA, Desai AR, Drake JE, El-Madany TS, Gavazzi M, Görres CM, Gough CM, Goulden M, Gregg J, Gutiérrez Del Arroyo O, He JS, Hirano T, Hopple A, Hughes H, Järveoja J, Jassal R, Jian J, Kan H, Kaye J, Kominami Y, Liang N, Lipson D, Macdonald CA, Maseyk K, Mathes K, Mauritz M, Mayes MA, McNulty S, Miao G, Migliavacca M, Miller S, Miniat CF, Nietz JG, Nilsson MB, Noormets A, Norouzi H, O'Connell CS, Osborne B, Oyonarte C, Pang Z, Peichl M, Pendall E, Perez-Quezada JF, Phillips CL, Phillips RP, Raich JW, Renchon AA, Ruehr NK, Sánchez-Cañete EP, Saunders M, Savage KE, Schrumpf M, Scott RL, Seibt U, Silver WL, Sun W, Szutu D, Takagi K, Takagi M, Teramoto M, Tjoelker MG, Trumbore S, Ueyama M, Vargas R, Varner RK, Verfaillie J, Vogel C, Wang J, Winston G, Wood TE, Wu J, Wutzler T, Zeng J, Zha T, Zhang Q, and Zou J
- Subjects
- Atmosphere, Carbon Dioxide analysis, Ecosystem, Methane analysis, Nitrous Oxide analysis, Reproducibility of Results, Respiration, Soil, Greenhouse Gases analysis
- Abstract
Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO
2 flux, commonly though imprecisely termed soil respiration (RS ), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open-source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long-term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS , the database design accommodates other soil-atmosphere measurements (e.g. ecosystem respiration, chamber-measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package., (© 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)- Published
- 2020
- Full Text
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681. Representing the function and sensitivity of coastal interfaces in Earth system models.
- Author
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Ward ND, Megonigal JP, Bond-Lamberty B, Bailey VL, Butman D, Canuel EA, Diefenderfer H, Ganju NK, Goñi MA, Graham EB, Hopkinson CS, Khangaonkar T, Langley JA, McDowell NG, Myers-Pigg AN, Neumann RB, Osburn CL, Price RM, Rowland J, Sengupta A, Simard M, Thornton PE, Tzortziou M, Vargas R, Weisenhorn PB, and Windham-Myers L
- Abstract
Between the land and ocean, diverse coastal ecosystems transform, store, and transport material. Across these interfaces, the dynamic exchange of energy and matter is driven by hydrological and hydrodynamic processes such as river and groundwater discharge, tides, waves, and storms. These dynamics regulate ecosystem functions and Earth's climate, yet global models lack representation of coastal processes and related feedbacks, impeding their predictions of coastal and global responses to change. Here, we assess existing coastal monitoring networks and regional models, existing challenges in these efforts, and recommend a path towards development of global models that more robustly reflect the coastal interface.
- Published
- 2020
- Full Text
- View/download PDF
682. Downscaling satellite soil moisture using geomorphometry and machine learning.
- Author
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Guevara M and Vargas R
- Subjects
- Environmental Monitoring, Remote Sensing Technology methods, Reproducibility of Results, Machine Learning, Satellite Imagery, Soil chemistry, Water analysis
- Abstract
Annual soil moisture estimates are useful to characterize trends in the climate system, in the capacity of soils to retain water and for predicting land and atmosphere interactions. The main source of soil moisture spatial information across large areas (e.g., continents) is satellite-based microwave remote sensing. However, satellite soil moisture datasets have coarse spatial resolution (e.g., 25-50 km grids); and large areas from regional-to-global scales have spatial information gaps. We provide an alternative approach to predict soil moisture spatial patterns (and associated uncertainty) with higher spatial resolution across areas where no information is otherwise available. This approach relies on geomorphometry derived terrain parameters and machine learning models to improve the statistical accuracy and the spatial resolution (from 27km to 1km grids) of satellite soil moisture information across the conterminous United States on an annual basis (1991-2016). We derived 15 primary and secondary terrain parameters from a digital elevation model. We trained a machine learning algorithm (i.e., kernel weighted nearest neighbors) for each year. Terrain parameters were used as predictors and annual satellite soil moisture estimates were used to train the models. The explained variance for all models-years was >70% (10-fold cross-validation). The 1km soil moisture grids (compared to the original satellite soil moisture estimates) had higher correlations (improving from r2 = 0.1 to r2 = 0.46) and lower bias (improving from 0.062 to 0.057 m3/m3) with field soil moisture observations from the North American Soil Moisture Database (n = 668 locations with available data between 1991-2013; 0-5cm depth). We conclude that the fusion of geomorphometry methods and satellite soil moisture estimates is useful to increase the spatial resolution and accuracy of satellite-derived soil moisture. This approach can be applied to other satellite-derived soil moisture estimates and regions across the world., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
- Full Text
- View/download PDF
683. Greenhouse Gas Fluxes From Tree Stems.
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Vargas R and Barba J
- Subjects
- Carbon Dioxide, Greenhouse Effect, Methane, Nitrous Oxide, Soil, Trees, Greenhouse Gases
- Abstract
Tree stems exchange carbon dioxide, methane, and nitrous oxide with the atmosphere. The biophysical mechanisms controlling these fluxes are not fully understood, and consequently are not included in process-based models. We highlight advances and opportunities that will allow quantification of the role of these plant structures in the local-to-global balance of greenhouse gases (GHGs)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
684. Benign rolandic epilepsy and generalized paroxysms: A study of 13 patients.
- Author
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Vargas R, Beltrán L, Lizama R, Valenzuela GR, and Caraballo R
- Subjects
- Anticonvulsants, Child, Child, Preschool, Epilepsy, Rolandic drug therapy, Female, Humans, Levetiracetam, Male, Piracetam analogs & derivatives, Piracetam therapeutic use, Retrospective Studies, Seizures diagnosis, Seizures drug therapy, Seizures physiopathology, Valproic Acid therapeutic use, Brain physiopathology, Electroencephalography, Epilepsy, Rolandic diagnosis, Epilepsy, Rolandic physiopathology
- Abstract
Purpose: To present a retrospective study of 13 children with benign epilepsy with centrotemporal spikes (BECTS), also known as benign rolandic epilepsy (BRE), associated with generalized spikes and waves as the only EEG manifestation at onset., Method: Charts of children with typical clinical criteria of BRE electroclinically followed-up between February 2000 and February 2015 were reviewed., Results: Among 309 patients who met the electroclinical criteria of BRE, we identified 13 children who presented with the typical clinical manifestations but who, on the EEG, only had generalized paroxysms at onset that continued along the course of the syndrome. Generalized spike-and-wave discharges were observed in all patients when awake and during sleep (100%). During the evolution no particular electroclinical pattern was observed. The patients responded well to antiepileptic drugs, such as valproic acid and levetiracetam. Outcome was good in all patients., Conclusions: We found evidence that patients with BRE may have generalized EEG discharges at onset as the sole manifestation lasting throughout the course of the syndrome. In some, focal paroxysms developed later. The course was benign. In our group of patients, clinical features and evolution were similar to those of typical cases of BRE. Response to valproic acid and levetiracetam was found to be particularly good., (Copyright © 2018 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
685. Potential bias of daily soil CO 2 efflux estimates due to sampling time.
- Author
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Cueva A, Bullock SH, López-Reyes E, and Vargas R
- Abstract
Soil respiration (Rs) has been usually measured during daylight hours using manual chambers. This approach assumes that measurements made during a typical time interval (e.g., 9 to 11 am) represent the mean daily value; locally, this may not always be correct and could result in systematic bias of daily and annual Rs budgets. We propose a simple method, based on the temporal stability concept, to determine the most appropriate time of the day for manual measurements to capture a representative mean daily Rs value. We introduce a correction factor to adjust for biases due to non-optimally timed sampling. This approach was tested in a semiarid shrubland using 24 hr campaigns using two treatments: trenched plots and plots with shrubs. In general, we found optimum times were at night and potential biases ranged from -29 to + 40% in relation to the 24 hr mean of Rs, especially in trenched plots. The degree of bias varied between treatments and seasons, having a greater influence during the wet season when efflux was high than during the dry season when efflux was low. This study proposes a framework for improving local Rs estimates that informs how to decrease temporal uncertainties in upscaling to the annual total.
- Published
- 2017
- Full Text
- View/download PDF
686. A multi-species synthesis of physiological mechanisms in drought-induced tree mortality.
- Author
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Adams HD, Zeppel MJB, Anderegg WRL, Hartmann H, Landhäusser SM, Tissue DT, Huxman TE, Hudson PJ, Franz TE, Allen CD, Anderegg LDL, Barron-Gafford GA, Beerling DJ, Breshears DD, Brodribb TJ, Bugmann H, Cobb RC, Collins AD, Dickman LT, Duan H, Ewers BE, Galiano L, Galvez DA, Garcia-Forner N, Gaylord ML, Germino MJ, Gessler A, Hacke UG, Hakamada R, Hector A, Jenkins MW, Kane JM, Kolb TE, Law DJ, Lewis JD, Limousin JM, Love DM, Macalady AK, Martínez-Vilalta J, Mencuccini M, Mitchell PJ, Muss JD, O'Brien MJ, O'Grady AP, Pangle RE, Pinkard EA, Piper FI, Plaut JA, Pockman WT, Quirk J, Reinhardt K, Ripullone F, Ryan MG, Sala A, Sevanto S, Sperry JS, Vargas R, Vennetier M, Way DA, Xu C, Yepez EA, and McDowell NG
- Subjects
- Climate Change, Cycadopsida physiology, Magnoliopsida physiology, Population Dynamics, Stress, Physiological, Carbon deficiency, Droughts, Plant Transpiration physiology, Trees physiology, Xylem physiology
- Abstract
Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.
- Published
- 2017
- Full Text
- View/download PDF
687. On the multi-temporal correlation between photosynthesis and soil CO2 efflux: reconciling lags and observations.
- Author
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Vargas R, Baldocchi DD, Bahn M, Hanson PJ, Hosman KP, Kulmala L, Pumpanen J, and Yang B
- Subjects
- Carbon metabolism, Cell Respiration, Poaceae metabolism, Seasons, Temperature, Time Factors, Trees metabolism, Carbon Dioxide metabolism, Ecosystem, Photosynthesis, Poaceae physiology, Soil chemistry, Trees physiology
- Abstract
Although there is increasing evidence of the temporal correlation between photosynthesis and soil CO(2) efflux, no study has so far tested its generality across the growing season at multiple study sites and across several time scales. Here, we used continuous (hourly) data and applied time series analysis (wavelet coherence analysis) to identify temporal correlations and time lags between photosynthesis and soil CO(2) efflux for three forests from different climates and a grassland. Results showed the existence of multi-temporal correlations at time periods that varied between 1 and 16 d during the growing seasons at all study sites. Temporal correlations were strongest at the 1 d time period, with longer time lags for forests relative to the grassland. The multi-temporal correlations were not continuous throughout the growing season, and were weakened when the effect of variations in soil temperature and CO(2) diffusivity on soil CO(2) efflux was taken into account. Multi-temporal correlations between photosynthesis and soil CO(2) efflux exist, and suggest that multiple biophysical drivers (i.e. photosynthesis, soil CO(2) diffusion, temperature) are likely to coexist for the regulation of allocation and transport speed of carbon during a growing season. Future studies should consider the multi-temporal influence of these biophysical drivers to investigate their effect on the transport of carbon through the soil-plant-atmosphere continuum., (No claim to original US government works. New Phytologist © 2011 New Phytologist Trust.)
- Published
- 2011
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688. Looking deeper into the soil: biophysical controls and seasonal lags of soil CO2 production and efflux.
- Author
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Vargas R, Baldocchi DD, Allen MF, Bahn M, Black TA, Collins SL, Yuste JC, Hirano T, Jassal RS, Pumpanen J, and Tang J
- Subjects
- Ecosystem, Seasons, Temperature, Time, Trees, Water, Carbon Dioxide chemistry, Carbon Dioxide metabolism, Soil analysis, Soil Microbiology
- Abstract
We seek to understand how biophysical factors such as soil temperature (Ts), soil moisture (theta), and gross primary production (GPP) influence CO2 fluxes across terrestrial ecosystems. Recent advancements in automated measurements and remote-sensing approaches have provided time series in which lags and relationships among variables can be explored. The purpose of this study is to present new applications of continuous measurements of soil CO2 efflux (F0) and soil CO2 concentrations measurements. Here we explore how variation in Ts, theta, and GPP (derived from NASA's moderate-resolution imaging spectroradiometer [MODIS]) influence F0 and soil CO2 production (Ps). We focused on seasonal variation and used continuous measurements at a daily timescale across four vegetation types at 13 study sites to quantify: (1) differences in seasonal lags between soil CO2 fluxes and Ts, theta, and GPP and (2) interactions and relationships between CO2 fluxes with Ts, theta, and GPP. Mean annual Ts did not explain annual F0 and Ps among vegetation types, but GPP explained 73% and 30% of the variation, respectively. We found evidence that lags between soil CO2 fluxes and Ts or GPP provide insights into the role of plant phenology and information relevant about possible timing of controls of autotrophic and heterotrophic processes. The influences of biophysical factors that regulate daily F0 and Ps are different among vegetation types, but GPP is a dominant variable for explaining soil CO2 fluxes. The emergence of long-term automated soil CO2 flux measurement networks provides a unique opportunity for extended investigations into F0 and Ps processes in the near future.
- Published
- 2010
- Full Text
- View/download PDF
689. Ecosystem CO2 fluxes of arbuscular and ectomycorrhizal dominated vegetation types are differentially influenced by precipitation and temperature.
- Author
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Vargas R, Baldocchi DD, Querejeta JI, Curtis PS, Hasselquist NJ, Janssens IA, Allen MF, and Montagnani L
- Subjects
- Geography, Light, Plants classification, Carbon Dioxide physiology, Climate, Ecosystem, Mycorrhizae physiology, Plant Physiological Phenomena, Rain, Temperature
- Abstract
Here, we explore how interannual variations in environmental factors (i.e. temperature, precipitation and light) influence CO(2) fluxes (gross primary production and ecosystem respiration) in terrestrial ecosystems classified by vegetation type and the mycorrhizal type of dominant plants (arbuscular mycorrhizal (AM) or ectomycorrhizal (EM)). We combined 236 site-year measurements of terrestrial ecosystem CO(2) fluxes and environmental factors from 50 eddy-covariance flux tower sites with information about climate, vegetation type and dominant plant species. Across large geographical distances, interannual variations in ecosystem CO(2) fluxes for EM-dominated sites were primarily controlled by interannual variations in mean annual temperature. By contrast, interannual variations in ecosystem CO(2) fluxes at AM-dominated sites were primarily controlled by interannual variations in precipitation. This study represents the first large-scale assessment of terrestrial CO(2) fluxes in multiple vegetation types classified according to dominant mycorrhizal association. Our results support and complement the hypothesis that bioclimatic conditions influence the distribution of AM and EM systems across large geographical distances, which leads to important differences in the major climatic factors controlling ecosystem CO(2) fluxes.
- Published
- 2010
- Full Text
- View/download PDF
690. [Physiological response of experimental challenge of Ichthyophthirius multifiliis (Fouquet, 1876) in jundiá (Rhamdia quelen Quoy and Gaimard, 1824) fingerlings rather fed with different lipid sources].
- Author
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Vargas RJ, de Souza SM, Mabilia RG, Carlet F, and Baggio SR
- Subjects
- Animals, Catfishes immunology, Fish Diseases immunology, Fish Diseases mortality, Fish Diseases parasitology, Survival Rate, Catfishes parasitology, Ciliophora physiology, Ciliophora Infections veterinary, Diet, Fatty Acids administration & dosage
- Abstract
A limiting factor in the early stage of the jundiá (Rhamdia quelen Quoy; Gaimard, 1824) culture is the presence of diseases such as ichthyophthiriasis or "Ich". Dietary polyunsaturated fatty acids (PUFAs) have a potent immunomodulatory activity; and this activity depend of the fish species, quantity/quality of the dietary PUFAS. The aim of this study was evaluate the physiologic response of jundiá, rather fed diets with different sources of fatty acids when challenge to Ich disease. Fingerlings of jundiá (7.6+/-0.8g) were fed during seven weeks with five diets with a different lipid source: fish, linseed and corn oils. Then, the fish were challenged with the Ichthyophthirius multifiliis (Fouquet, 1876). On the 5(th) day, the presence of the disease was detected. Survival rate, blood samples and infection grade were recorded. Diets affect the survival rate of fingerlings, thus fish fed with diet with fish oil showed a higher survival. Hematocrit and infestation grade no recorder differences among treatment. The differential analysis of white blood cells shows difference. The results point out, at first time in jundiá, that dietary lipids caused diversity physiologic response, this may be represent an opportunity for the disease treatment. New studies must be carrying out to deep knowledge found.
- Published
- 2008
- Full Text
- View/download PDF
691. Beta-carotene from cassava (Manihot esculenta Crantz) leaves improves vitamin A status in rats.
- Author
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Siqueira EMA, Arruda SF, de Vargas RM, and de Souza EMT
- Subjects
- Animals, Biological Availability, Liver metabolism, Male, Plant Extracts administration & dosage, Plant Leaves chemistry, Rats, Rats, Wistar, Weight Gain drug effects, beta Carotene analysis, beta Carotene pharmacokinetics, Diet, Manihot chemistry, Vitamin A metabolism, Vitamin A Deficiency diet therapy, beta Carotene administration & dosage
- Abstract
The bioavailability of beta-carotene from cassava (Manihot esculenta Crantz) leaves was assayed in vitamin A deficient Wistar rats (Rattus norvegicus). Rats were separated into three groups and fed with a modified AIN-93G--vitamin A deficient--diet. Deficient rat received this diet without any additional vitamin A source. Controls received the diet with 7200 microg of synthetic beta-carotene (control), while experimentals (test) received 19.5 g of cassava leaves powder per kg of diet. The cassava leaves with beta-carotene promotes similar growth and tissue weight in rats to the synthetic beta-carotene. The relative bioavailability, estimated as the Retinol Accumulation Factor (RAF), was 16.5 and 27.5 for control and test groups, respectively, indicating that control and test rats should have an intake of 16.5 microg or 27.5 microg of beta-carotene from synthetic form or cassava leaves powder for each 1 microg of hepatic retinol stored, respectively. The cassava leaves beta-carotene bioavailability was lower than the synthetic beta-carotene probably because the beta-carotene from the leaf matrix may be bounded to protein complex or inside organelles, which impair carotenoid absorption. Our findings showed that beside the hepatic retinol recovery, cassava leaf beta-carotene could maintain rat growth and avoid vitamin A deficient symptoms.
- Published
- 2007
- Full Text
- View/download PDF
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