Taxonomic and functional responses of macroinvertebrates to riparian forest conversion in tropical streams.

Land use change threatens the ecological integrity of tropical rivers and streams; however, few studies have simultaneously analyzed the taxonomic and functional responses of tropical macroinvertebrates to riparian forest conversion. Here, we used community structure, functional diversity, and stable isotope analyses to assess the impacts of riparian deforestation on macroinvertebrate communities of streams in southern Mexico. Monthly sampling during the dry season was conducted in streams with riparian forest (forest streams), and in streams with pasture dominating the riparian vegetation (pasture streams). Samples were collected for water quality (physical-chemical variables, nutrient concentrations, and total suspended solids), organic matter (leaf litter abundance and algal biomass), and macroinvertebrate abundance and diversity. Higher temperature, conductivity, suspended solids, and chlorophyll a were detected in pasture streams, while nitrate concentrations and leaf litter biomass were greater in forest streams. Macroinvertebrate density was higher in pasture sites, while no differences in taxonomic diversity and richness were found between land uses. Functional evenness was greater in forest streams, while richness and divergence were similar between land uses, despite differences in taxonomic composition. Environmental variables were associated with taxa distribution but not with functional traits, suggesting current conditions still promote redundancy in ecological function. Isotopic analyses indicated consumers in pasture streams were enriched in 13C and 15N relative to forest streams, potentially reflecting the higher algal biomass documented in pasture systems. Isotopic niches were broader and more overlapped in pasture streams, indicating more generalist feeding habits. No significant losses of taxonomic or functional diversity were detected in pasture streams. However, changes in trophic ecology suggest landscape-level processes are altering macroinvertebrate feeding habits in streams. The changes we observed in habitat, water quality, and macroinvertebrate community were related to the removal of the riparian vegetation, suggesting the structure and function of the focal systems would benefit from riparian restoration.

Global patterns and drivers of ecosystem functioning in rivers and riparian zones.

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth's biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented "next-generation biomonitoring" by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

Evaluación de los niveles séricos de la interleuquina-8 y de la proteína C reactiva en sujetos obesos / Serum interleukin-8 levels and C-reactive protein in obese subjects

La obesidad incrementa el riesgo de sufrir enfermedad cardiovascular y favorece el desarrollo de aterosclerosis. Los mecanismos que unen la obesidad con la aterosclerosis están en estudio. La IL-8 es una citoquina con propiedades aterogénicas y la proteína C reactiva (PCR) es una molécula proinflamatoria. El objetivo de este estudio es determinar las concentraciones séricas de IL-b y de PCR en sujetos obesos y relacionar las concentraciones séricas de IL-8 y de PCR con los parámetros antropométricos y bioquímicos. La población en estudio estuvo conformada por 48 sujetos obesos y 25 sujetos normopeso como grupo control. Los niveles séricos de IL-8 y de PCR se determinaron en estado de ayuno, así como los parámetros bioquímicos sanguíneos y los parámetros antropométricos. No se observó un aumento de los niveles séricos de IL-8 en los sujetos obesos en comparación con el grupo control (p = 0,57). Las concentraciones séricas de IL-8 no se correlacionan con el índice de masa corporal (IMC) ni con el índice cintura-cadera (ICC) en ninguno de los grupos estudio. Los niveles de PCR se encontraron aumentados en sujetos obesos en comparación con sujetos normopeso (p = 0,006). Los niveles séricos de PCR se correlacionan positivamente con el IMC en sujetos obesos (r = 0,22 p = 0,29). En conclusión, aunque el tejido adiposo puede producir IL-8, esta producción contribuye poco con los niveles séricos de IL-8 en sujetos obesos. Los niveles séricos de PCR se encuentran aumentados en sujetos obesos, los cual puede ser consecuencia del exceso de tejido adiposo

Polyphasic characterization of Pseudomonas stutzeri CLN100 which simultaneously degrades chloro- and methylaromatics: a new genomovar within the species.

Strain CLN100 was isolated after enrichment on mineral medium with chloronaphthalene as the only carbon and energy source. It was able to use simultaneously and productively chloro- and methyl-derivatives of naphthalene and salicylate through a chromosomally encoded meta pathway. Phenotypic, chemotaxonomic and genotypic characterization classified strain CLN100 as a member of the species Pseudomonas stutzeri. DNA-DNA hybridizations, 16S rDNA, gyrB, rpoD sequences, and molecular fingerprinting indicate that strain CLN100 is a representative of a new genomovar (genomovar 10) within the species.