Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

Desarrollo embrionario en yuca (Manihot esculenta Crantz), receptividad de estigmas y potencial de cruzamientos con higuerilla (Ricinus communis L.) para la producción de dobles haploides

La técnica de dobles haploides (DH) permite en un solo paso la obtención de plantas completamente homocigotas y homogéneas. Esta se ha convertido en una herramienta de rutina en muchas especies de cultivos importantes, como el maíz en donde se han empleado líneas haploides para obtener híbridos diseñados altamente productivos. Sin embargo, en el mejoramiento vegetal de la yuca, -un cultivo también con crecientes demandas agrícolas-, este modelo no puede aplicarse actualmente, debido a lo largo del ciclo reproductivo, la naturaleza heterocigótica del cultivo y su sensibilidad a la endogamia. No obstante, para poder aplicar esta técnica en yuca, se requiere de investigación en la biología reproductiva del cultivo. Esto incluye investigación básica en la biología floral que contribuya a un mejor entendimiento de los procesos de polinización y formación de la semilla. En esta tesis estos conocimientos permiten desarrollar una guía de conceptos para el mejoramiento conducido por cruzamientos amplios, los cuales son un camino para inducir plantas haploides. Los objetivos de investigación fueron tres, dos de estos sobre el estudio del comportamiento de la biología reproductiva de la yuca, en el capítulo 2, la compatibilidad de polen en el pistilo y en el capítulo 3, el desarrollo del embrión, y finalmente en el capítulo 4, la estimación de la eficiencia de cruzamientos amplios en campo entre yuca con higuerilla para inducir plantas haploides. Para ello, se observó la interacción in vivo del polen de yuca e higuerilla en el pistilo de la yuca con microscopía de fluorescencia. También, se realizaron observaciones histológicas con la técnica de parafina del embrión en diferentes etapas de desarrollo. Y finalmente se realizaron polinizaciones con polen de higuerilla en estilos de yuca con el uso de aplicación de hormonas de crecimiento 2,4D y AG3 y se evaluó el cuajamiento de los frutos obtenidos.Doctorad

¿Cómo se da la construcción del saber ó conocimiento tradicional?

El conocimiento tradicional se construye a través de la experiencia y es difundido principalmente por el lenguaje oral. Es de esa forma en que dichos conocimientos pueden acoplarse a las actividades cotidianas de una comunidad o región y eventualmente pasan a ser parte de su cultura. En este sentido, toda construcción mental tendrá divergencias fuertemente vinculadas al contexto geográfico e histórico específico de la comunidad, en sus diferentes niveles, especialmente en términos de tecnología y aspiraciones de vida

Protocol and analysis of in vivo pollen tuve growth = Protocolo y análisis del crecimiento in vivo del tubo polínico en yuca/mandioca

This 9-minute video describes the protocol used in cassava for the analysis pollen tube grow in vivo. Then images of pollen tube growth taken with a fluorescence microscope are presented to illustrate the process. Finally an overall description of the time required for the pollen tube tip to reach the embryo sac is presented. Este video de 9 minutos describe el protocolo usado en yuca/mandioca para el análisis del crecimiento del tubo polínico in vivo. Luego se presentan numerosas fotografías, tomadas en microscopio de fluorescencia, para ilustrar el proceso hasta que el tubo polínico llega al saco embrionario. Finalmente se presenta información de los tiempos requeridos en todo el proceso

Reproductive biology in cassava: stigma receptivity and pollen tube growth

Knowledge on the reproductive biology of cassava, relevant to breeders and molecular geneticists, is still limited. Therefore, different studies were carried out to determine the duration of stigma receptivity and the rate of pollen tube growth. Inflorescences were covered for up to 3 days after the first opening of the bracts (e.g. anthesis day) to prevent open pollination. Results indicate that fruit and seed set are drastically reduced when flowers were covered for 2 or 3 days. However, fruits and seeds were obtained even from flowers that had been covered for 3 days after anthesis, although at low frequency. The rate of pollen tube growth was assessed in many combinations of female and male progenitors crossed through controlled pollinations and collecting the pistils at varying hours after pollination (HAP). Pollen tube growth is fast during the first 6 HAP reaching the tip of the nucellar beak. The growth slows down thereafter, taking 10 additional hours to reach the end of the beak. The growth of pollen tubes slows down even further until they enter the embryo sac. Only 10% of samples showed pollen tubes entering the embryo sac between 48 and 66 HAP. Although several tubes may reach the nucellar beak, only one was observed entering the embryo sac. Results, across the different experiments, were highly variable suggesting that the timeline of fertilization is influenced both by genotypic and environmental factors as well as the manual manipulation of inflorescences and cyathia

Description of embryo development in cassava = Descripción del desarrollo embrionario en yuca

This 16-minute video describes the protocol used for the preparation of sections for the histological analysis of cassava pistils of different ages after anthesis. Consolidated results after studying hundreds of samples, present a chronological description of embryo sac and the embryo appearance at different stages of development. Este video de 16 minutos describe el protocolo usado en la preparación de muestras para el estudio histológico de pistilos de yuca/mandioca a diferentes edades luego de la antesis. Resultados consolidados, después de analizar cientos de secciones, presentan una descripción cronológica de los diferentes estadios de desarrollo embrionario

Extrahypothalamic oxytocin neurons drive stress-induced social vigilance and avoidance.

Oxytocin increases the salience of both positive and negative social contexts and it is thought that these diverse actions on behavior are mediated in part through circuit-specific action. This hypothesis is based primarily on manipulations of oxytocin receptor function, leaving open the question of whether different populations of oxytocin neurons mediate different effects on behavior. Here we inhibited oxytocin synthesis in a stress-sensitive population of oxytocin neurons specifically within the medioventral bed nucleus of the stria terminalis (BNSTmv). Oxytocin knockdown prevented social stress-induced increases in social vigilance and decreases in social approach. Viral tracing of BNSTmv oxytocin neurons revealed fibers in regions controlling defensive behaviors, including lateral hypothalamus, anterior hypothalamus, and anteromedial BNST (BNSTam). Oxytocin infusion into BNSTam in stress naïve mice increased social vigilance and reduced social approach. These results show that a population of extrahypothalamic oxytocin neurons plays a key role in controlling stress-induced social anxiety behaviors

Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L-1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4 degrees C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature.Peer reviewe