PEPTIDOS TOXICOS Y NO TOXICOS DE CIANOBACTERIAS EN CUERPOS DE AGUA DULCE DE LA V REGION, CHILE

En Chile se ha detectado la presencia de algunos géneros de cianobacterias que pueden producir potentes hepatotoxinas y neurotoxinas, las que pueden ser letales para humanos y animales. En el presente trabajo se determinó la presencia de dos géneros de cianobacterias no tóxicos: Chroococcus y Spirulina; y cuatro génerosde cianobacterias productores de toxina, Anabaena, Anabaenopsis, Microcystis y Oscillatoria en tres diferentes cuerpos de agua de la V Región: Lago Peñuelas (Valparaíso), Tranque Recreo (Villa Alemana) y Embalse Los Aromos (Limache). Además se detectó la presenciade hepatotoxinas por MALDI-TOF MS encontrándose microcistina-RR, -LA, -YR y nodularina en Embalse Los Aromos, microcistina-LA en Tranque Recreo y microcistina- RR y LA en Lago Peñuelas. Adicionalmente enalgunas de las muestras se detectó la presencia de péptidos no tóxicos, que presentan actividad biológica tales como aeruginosinas, cianopeptolinas y microgininas. Como estos cuerpos de agua dulce sonutilizados para abastecimiento público y para la recreación, es importante diseñar planes de tratamiento y monitoreo para detectar y evitar los riesgos a la salud  humana y animal provocado por estos microorganismos

Preliminary application of a simulation model to reproduce hazelnut development and growth in Italy, Georgia and Chile

Process-based simulation models have been increasingly used in agriculture for crop yield forecasting and in-season monitoring of crop growth, to support stakeholders, from farmers to agribusiness companies, and regional policies. The study shows the application of a modelling solution for hazelnut trees, which provides a dynamic simulation of the plant physiological processes associated with development and growth, as affected by variable agro-pedo-climatic conditions. The modelling solution was tested using reference data collected in 2015-2016 in four hazelnut orchards placed in Italy (Baldissero d\u2019Alba, Oriolo Romano), Georgia (Chitaskari) and Chile (Camarico). The data collection (i.e., growth stage, LAI, fruit biomass, crown size, soil water content) was carried out on ten adjacent plants grown in a homogenous area of the field. Simulation results indicated a good correlation with observed phenological development, with R 2 >0.7 and relative root mean square error RRMSE <20% for vegetative and reproductive phases. The modelling solution was able to reproduce the LAI dynamics (mean absolute error MAE <0.77 m 2 m -2 ; RRMSE <23.24%), characterized by large differences across sites, being reproduced by adjusting parameters related to crown shape and leaf area density. Similarly, the yield trend, that shows an average production for the four sites higher in 2016 (6.32 kg plant -1 ) than in 2015 (4.45 kg plant -1 ), was correctly reproduced, with simulations leading to MAE between 0.25 and 1.02 kg plant -1 . This modelling solution is a promising tool to provide information on the orchard status and to support evaluations on crop performance in different areas and climate change scenarios, even if further tests are needed to consolidate these preliminary results

Dynamics of Lignin: Molecular Dynamics and Neutron Scattering

Lignocellulosic biomass, the major secondary plant cell wall material, is composed of three major components: lignin, hemicellulose, and cellulose. Lignin, an amorphous polymer that does not have a regular chemical structure, plays an important role in the recalcitrance of lignocellulosic biomass to deconstruction by blocking enzymatic hydrolysis of cellulose. Understanding the dynamics of the lignin polymer is fundamental for technological applications involving biomass, such as biofuel production. In this chapter, we discuss the application of neutron scattering and molecular dynamics simulation used to study the atomic dynamics of lignin. We focus on glass transition, the technologically most important dynamical processes of lignin. We explain the impact of environmental factors, such as hydration and temperature, on the magnitude of lignin atomic fluctuations and the relaxation processes at temperatures above and below the glass transition temperature. © 2019 American Chemical Society.Office of Science U.S. Department of Energy U.S. Department of Energy: FWP ERKP752This research was supported by the Genomic Science Program, Office of Biological and Environmental Research, U. S. Department of Energy (DOE), under Contract FWP ERKP752. This research used resources of the (i) National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231; and (ii) the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory