Emission of volatile halogenated compounds, speciation and localization of bromine and iodine in the brown algal genome model Ectocarpus siliculosus

This study explores key features of bromine and iodine metabolism in the filamentous brown alga and genomics model Ectocarpus siliculosus. Both elements are accumulated in Ectocarpus, albeit at much lower concentration factors (2-3 orders of magnitude for iodine, and < 1 order of magnitude for bromine) than e.g. in the kelp Laminaria digitata. Iodide competitively reduces the accumulation of bromide. Both iodide and bromide are accumulated in the cell wall (apoplast) of Ectocarpus, with minor amounts of bromine also detectable in the cytosol. Ectocarpus emits a range of volatile halogenated compounds, the most prominent of which by far is methyl iodide. Interestingly, biosynthesis of this compound cannot be accounted for by vanadium haloperoxidase since the latter have not been found to catalyze direct halogenation of an unactivated methyl group or hydrocarbon so a methyl halide transferase-type production mechanism is proposed

Applicability of DNA barcoding-based analyses on the diet of the gray brocket deer (Subulo gouazoubira) in xeric hillside forests

In this study, we explore the applicability of DNA barcoding, specifically targeting the chloroplast DNA (cpDNA) sequences, particularly the trnL (UAA) intron region, to analyze the diet of gray brocket deer. This approach offers improved taxonomic resolution and the ability to identify species with greater precision compared to traditional methods. The study was conducted in the "Reserva Natural Salus" in Uruguay, covering a range of vegetation types, where gray brocket deer coexist with other exotic ungulates. A local reference database of trnL (UAA) sequences was established, incorporating both GenBank data and sequences obtained from native species in the study area. Fecal samples were collected in summer and winter, and DNA was extracted and amplified for metabarcoding analysis in pooled samples for each season. For each sample 28,229 and 33,588 reads were obtained respectively, which together corresponded to 25 Operational Taxonomic Units (OTUs). The species Rubus ulmifolius and Schinus engleri were the most represented in the diet with 69.6 % of the summer reads, whereas in winter, 68.7 % of the reads corresponded only to Schinus engleri. These findings indicate that gray brocket deer consume species that have higher nutritional value, which may be linked to their capacity to thrive in young and productive ecosystems. This study demonstrates the feasibility of DNA barcoding for dietary analysis in gray brocket deer and provides valuable insights into their food habits in the "Reserva Natural Salus". Further improvements to increase the reference databases of native species and the exploration of additional genetic markers are recommended for enhanced species-level discrimination in dietary analysis studies. This methodology is promising for future research as diet studies have an impact on species management, habitat conservation and biodiversity conservation efforts.En este estudio, exploramos la aplicabilidad de los códigos de barras de ADN, utilizando la región de intrón del cloroplasto trnL (UAA), para analizar la dieta del guazubirá. Este enfoque ofrece una buena resolución taxonómica y la capacidad de identificar especies con mayor precisión que con los métodos tradicionales basados en análisis microhistológicos de fragmentos vegetales. El estudio se realizó en la "Reserva Natural Salus" de Uruguay, que presenta distintos tipos de vegetación, incluyendo bosques nativos, plantaciones de pinos y eucaliptos, y afloramientos rocosos, donde el guazubirá convive con otros ungulados exóticos. Para el estudio se estableció una base de referencia local de secuencias trnL (UAA), incorporando registros de GenBank y secuencias obtenidas de especies nativas en el área de estudio. Se recolectaron muestras fecales en verano e invierno, se extrajo y amplificó el ADN para análisis de metabarcoding, agrupando las muestras colectadas en cada estación. Para cada uno de los muestreos se obtuvieron 28,229 y 33,588 lecturas respectivamente, que en conjunto representaron 25 Unidades Taxonómicas Operativas (UTOs). Sin embargo, las especies Rubus ulmifolius y Schinus engleri fueron las más representadas con el 69.6 % de las lecturas de verano, para invierno el 68.7 % de las lecturas fueron para Schinus engleri. Estos hallazgos indican que el guazubirá consume especies que tienen alto valor nutricional, lo cual podría relacionarse con la habilidad de esta especie a adaptarse a ecosistemas jóvenes y altamente productivos. Este estudio demuestra la viabilidad de estudios de dieta basados en códigos de barras de ADN para ciervos neotropicales y proporciona información valiosa sobre los hábitos alimentarios del guazubirá en la "Reserva Natural Salus". Se recomienda ampliar las bases de secuencias de referencia de especies nativas y explorar otros marcadores genéticos adicionales para mejorar el poder de discriminación a nivel de especie en los estudios de metabarcoding de especies vegetales. Esta metodología es prometedora para futuras investigaciones, ya que los estudios de dieta tienen un impacto en el manejo de especies, la conservación del hábitat y los esfuerzos de conservación de la biodiversidad

Theoretical and experimental activities on opacities for a good interpretation of seismic stellar probes

Opacity calculations are basic ingredients of stellar modelling. They play a crucial role in the interpretation of acoustic modes detected by SoHO, COROT and KEPLER. In this review we present our activities on both theoretical and experimental sides. We show new calculations of opacity spectra and comparisons between eight groups who produce opacity spectra calculations in the domain where experiments are scheduled. Real differences are noticed with real astrophysical consequences when one extends helioseismology to cluster studies of different compositions. Two cases are considered presently: (1) the solar radiative zone and (2) the beta Cephei envelops. We describe how our experiments are performed and new preliminary results on nickel obtained in the campaign 2010 at LULI 2000 at Polytechnique.Comment: 6 pages, 4 figures, invited talk at SOHO2

Earthworms Use Odor Cues to Locate and Feed on Microorganisms in Soil

Earthworms are key components of temperate soil ecosystems but key aspects of their ecology remain unexamined. Here we elucidate the role of olfactory cues in earthworm attraction to food sources and document specific chemical cues that attract Eisenia fetida to the soil fungi Geotrichum candidum. Fungi and other microorganisms are major sources of volatile emissions in soil ecosystems as well as primary food sources for earthworms, suggesting the likelihood that earthworms might profitably use olfactory cues to guide foraging behavior. Moreover, previous studies have documented earthworm movement toward microbial food sources. But, the specific olfactory cues responsible for earthworm attraction have not previously been identified. Using olfactometer assays combined with chemical analyses (GC-MS), we documented the attraction of E. fetida individuals to filtrate derived from G. candidum colonies and to two individual compounds tested in isolation: ethyl pentanoate and ethyl hexanoate. Attraction at a distance was observed when barriers prevented the worms from reaching the target stimuli, confirming the role of volatile cues. These findings enhance our understanding of the mechanisms underlying key trophic interactions in soil ecosystems and have potential implications for the extraction and collection of earthworms in vermiculture and other applied activities

Reciprocal influence of the p53 and the hypoxic pathways

When cells sense a decrease in oxygen availability (hypoxia), they develop adaptive responses in order to sustain this condition and survive. If hypoxia lasts too long or is too severe, the cells eventually die. Hypoxia is also known to modulate the p53 pathway, in a manner dependent or not of HIF-1 (hypoxia-inducible factor-1), the main transcription factor activated by hypoxia. The p53 protein is a transcription factor, which is rapidly stabilised by cellular stresses and which has a major role in the cell responses to these stresses. The aim of this review is to compile what has been reported until now about the interconnection between these two important pathways. Indeed, according to the cell line, the severity and the duration of hypoxia, oxygen deficiency influences very differently p53 protein level and activity. Conversely, p53 is also described to affect HIF-1α stability, one of the two subunits of HIF-1, and HIF-1 activity. The direct and indirect interactions between HIF-1α and p53 are described as well as the involvement in this complex network of their respective ubiquitin ligases von Hippel Lindau protein and murine double minute 2. Finally, the synergistic or antagonistic effects of p53 and HIF-1 on some important cellular pathways are discussed

Residential mobility of middle-class and popular sectors: the city of Buenos Aires as an arrival destination

El artículo reflexiona acerca de los patrones de movilidad residencial de individuos y hogares de sectores populares y medios que residen en dos zonas de la Ciudad de Buenos Aires configuradas en torno a patrones disimiles de segregación. La movilidad residencial es un lente privilegiado para evidenciar de qué modo la experiencia de la clase es producida y reproducida en los modos de habitar. Mediante un abordaje cualitativo y biográfico hemos analizado las especificidades que presentan las movilidades residenciales de los diferentes sectores sociales. Se identifican patrones en tres dimensiones de la movilidad residencial: su espacialidad, los arreglos residenciales que los hogares despliegan y las motivaciones que guían sus desplazamientos. Los hallazgos presentados dan cuenta de los efectos que produce la posición en la estructura social sobre la movilidad residencial, así como su interacción con la propia estructuración del espacio.The article reconstructs residential mobility patterns of individuals and households from popular and middle-class sectors residing in two areas of the city of Buenos Aires, configured around dissimilar segregation patterns. Residential mobility is a powerful lens to show how the social class experience is produced and reproduced in modes of dwelling. Through a qualitative and biographical approach, we analyzed the specificities presented by residential mobilities of different social sectors. We identified patterns in the three dimensions of residential mobility: spatiality, the residential arrangements that households employ, and the motivations that guide their movements. The findings show the effects that the position in the social structure has on residential mobility, as well as its interaction with the spatial structure itself.publishedVersionFil: Cosacov, Andrea. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Cosacov, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas; Argentina.Fil: Di Virgilio, María Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación Gino Germani; Argentina.Fil: Najman, Mercedes. Universidad de Buenos Aires. Facultad de Ciencias Sociales; Argentina.Fil: Di Virgilio, María Mercedes. Universidad de Buenos Aires. Facultad de Ciencias Sociales; Argentina.Fil: Najman, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación Gino Germani; Argentina

The OASIS Mission

The Orbiting Astrophysical Observatory in Space (OASIS) is a mission to investigate Galactic Cosmic Rays (GCRs), a major feature of our galaxy. OASIS will use measurements of GCRs to determine the cosmic ray source, where they are accelerated, to investigate local accelerators and to learn what they can tell us about the interstellar medium and the processes that occur in it. OASIS will determine the astrophysical sources of both the material and acceleration of GCRs by measuring the abundances of the rare actinide nuclei and make direct measurements of the spectrum and anisotropy of electrons at energies up to approx.10 TeV, well beyond the range of the Fermi and AMS missions. OASIS has two instruments. The Energetic Trans-Iron Composition Experiment (ENTICE) instrument measures elemental composition. It resolves individual elements with atomic number (Z) from 10 to 130 and has a collecting power of 60m2.str.yrs, >20 times larger than previous instruments, and with improved resolution. The sample of 10(exp 10) GCRs collected by ENTICE will include .100 well-resolved actinides. The High Energy Particle Calorimeter Telescope (HEPCaT) is an ionization calorimeter that will extend the electron spectrum into the TeV region for the first time. It has 7.5 sq m.str.yrs of collecting power. This talk will describe the scientific objectives of the OASIS mission and its discovery potential. The mission and its two instruments which have been designed to accomplish this investigation will also be described