Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland

Indexación: Web of Science; Scopus.Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1). Diversity increased at noon, when the highest irradiances were measured (3.3-3.9 H', 1125 W m(-2)) compared to morning and afternoon (0.6-2.8 H'). This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (< 0.5%) in the pyrolibraries. A potential increase in the activity of Cyanobacteria and other phototrophic groups, e.g., Rhodobacterales, was observed and associated with UVR, suggesting the presence of photo activated repair mechanisms to resist high levels of solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite, and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in situ, but both functional groups (Nitrosomona and Nitrospira) appeared mainly in pyrolibraries generated from dark incubations. In total, our results reveal that both the structure and the diversity of the active bacteria community was extremely dynamic through the day, and showed marked shifts in composition that influenced nutrient recycling, highlighting how abiotic variation affects potential ecosystem functioning.http://journal.frontiersin.org/article/10.3389/fmicb.2016.01823/ful

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano

Indexación: Web of Science; Scopus.In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, H-3-leucine incorporation) response from short-term exposures to solar radiation. We sampled during austral spring seven stations categorized as: (a) source stations, with recently emerged groundwater (no-previous solar exposure); (b) stream running water stations; (c) stations connected to source waters but far downstream from source points; and (d) isolated ponds disconnected from ground sources or streams with a longer isolation and solar exposure history. Very high values of 0.25 mu E m(-2) s(-1), 72 W m(-2) and 12 W m(-2) were measured for PAR, UVA, and UVB incident solar radiation, respectively. The environmental factors measured formed two groups of stations reflected by principal component analyses (near to groundwater sources and isolated systems) where isolated ponds had the highest BSP and microbial abundance (35 microalgae taxa, picoeukaryotes, nanoflagellates, and bacteria) plus higher salinities and PO43- concentrations. BSP short-term response (4 h) to solar radiation was measured by H-3-leucine incorporation under four different solar conditions: full sun, no UVB, PAR, and dark. Microbial communities established in waters with the longest surface exposure (e.g., isolated ponds) had the lowest BSP response to solar radiation treatments, and thus were likely best adapted to solar radiation exposure contrary to ground source waters. These results support our light history (solar exposure) hypothesis where the more isolated the community is from ground water sources, the better adapted it is to solar radiation. We suggest that factors other than solar radiation (e.g., salinity, PO43-, NO3-) are also important in determining microbial productivity in heterogeneous environments such as the Salar de Huasco.http://journal.frontiersin.org/article/10.3389/fmicb.2016.01857/ful

Evaluation of direct sample injection as a fast, no-sample handling, approach for the LC-MS/MS monitoring of pharmaceuticals in different water matrices

The determination of drug residues in water, particularly in environmental water, is a hot topic due to the usual presence of these emerging contaminants in the aquatic environment and their potential negative impact on water quality. The most widely approach applied at present for their determination is the use of a solid phase extraction (SPE) step followed by the LC-MS/MS measurement. This is due to the theoretical need to preconcentrate the analytes and to produce “clean” sample extracts leading to less inferences in subsequent analysis. However, in LC-MS/MS based methods, the main interferences are not “visible” and are mostly due to matrix effects, which in fact are produced by unknown compounds that co-elute with the analytes and therefore not easily removed by SPE. As an alternative, an increasing trend is observed towards the use of direct injection (DI) of the samples, which is nowadays possible thank to the notable improvement in sensitivity of modern LCMS/MS instrumentation. In this work, both approaches, SPE and DI, have been evaluated for the determination of 16 pharmaceuticals in three different types of water: groundwater, surface water and effluent wastewater. The study has been performed by using pharmaceutical reference standards and their corresponding isotope-labelled internal standards (ILIS) for efficient matrix effects correction. Both methodologies have been compared in terms of matrix effects, sensitivity, and suitability for the analysis of real-world water samples. Our data show that DI is an efficient alternative to SPE, with satisfactory analyte recoveries for most pharmaceuticals, matrix effects even lower than in SPE, and sufficient sensitivity for most of applications. In addition, the absence of sample treatment minimizes potential errors associated with this step, and there is a notable saving in the analysis time and costs. The analysis of Quality Control (QC) samples included in different sample batch sequences has been used to support the feasibility of using DI in this type of analysis.Funding for open access charge: CRUE-Universitat Jaume

El precedente judicial y la excepción de inconstitucionalidad: Una revisión de la sentencia SU-140/19 y la vulneración del principio de seguridad jurídica y progresividad

The present article tries to highlight the thesis that the judicial precedent is not absolute for the judicial operators and that they can depart from it protected in the power of exception for unconstitutionality, based on a revision of Judgment SU140 / 19, analyzing the failure in the argumentative system of the same and emphasizing that it violates constitutional principles of the social state of lawsuch as the principle of legal certainty and the principle of progressivity, sufficient reason for the judges of instance to ignore said judicial precedent and in instead apply the preceding precedent recognizing the pension increases requested prior to March 29, 2020.El presente artículo pretende resaltar la tesis de que el precedente judicial no es absoluto para los operadores judiciales y que estos se pueden apartar del mismo amparados en la facultad de excepción por inconstitucionalidad, partiendo para ello de una revisión de Sentencia SU140/19, analizando la falencia en el sistema argumentativo de la misma y acentuando en que la misma vulnera principios constitucionales propios del estado social de derecho como el principio de la seguridad jurídica y el principio de progresividad, razón suficiente para que los jueces de instancia desconozcan dicho precedente judicial y en su lugar apliquen el precedente anterior reconociendo los incrementos pensionales solicitados con anterioridad al día 29 de marzo de 2020

Efecto de la adición de epicarpio de maracuyá (Passiflora edulis var. Flavicarpa) en la calidad de helado a base de leche

El objetivo de este estudio fue evaluar el efecto de la adición de epicarpio de maracuyá (EM) (Pasiflora edulis var. Flavicarpa) en las características de calidad de un helado a base de leche. Inicialmente se determinaron propiedades fisicoquímicas, tecnológicas, microbiológicas y antioxidantes presentes en el epicarpio de maracuyá, identificando su potencial uso como fuente de fibra dietaria para enriquecer alimentos con bajo contenido calórico. Se optimizó la incorporación de EM como sustituto parcial de grasa en la formulación de un helado de leche. Por último, se evaluó la estabilidad de una formulación optimizada de helado a base de leche, con incorporación de EM en comparación a un helado control y otro comercial, durante 60 días de almacenamiento. Los resultados demostraron que el contenido de grasa láctea se puede reducir de 4 a 3% (alrededor de 25% menos) empleando 0.97% de EM como sustituto parcial de grasa sin afectar las propiedades fisicoquímicas de un helado a base de leche. Durante 60 días de almacenamiento las muestras de helado con incorporación de EM presentaron variaciones significativas con lo cual las características de calidad se vieron afectadas positivamente en relación a las muestras control y comercial, siendo aptas microbiológicamente.//Abstract: The objective of this study was to evaluate the effect of the addition of passion fruit epicarp (EM) (Pasiflora edulis var. Flavicarpa) on the quality characteristics of a milk-based ice cream. Initially physicochemical, technological, microbiological and antioxidant properties present in the passion fruit epicarp were determined, identifying its potential use as a source of dietary fiber to enrich foods with low caloric content. Secondly, the incorporation of passion fruit epicarp (EM) as a partial fat substitute in the formulation of a milk-based ice cream was optimized. Finally, the stability of an optimized formulation milk-based ice cream based was evaluated, with incorporation of EM compared to a control and a commercial ice cream, during 60 days of storage. The results showed that the milk fat content can be reduced from 4 to 3% (around 25% less) using 0.97% EM as a partial fat substitute without affecting the physicochemical properties of a milk-based ice cream. During the 60 days of storage, the samples of ice cream with EM showed positive variations in the quality characteristics in relation to the control and commercial samples, being suitable microbiologically.Maestrí