2,257 research outputs found
PATHOGENICITY, TOXIGENIC POTENTIAL, AND GENOMICS OF \u3cem\u3eFusarium graminearum\u3c/em\u3e AND \u3cem\u3eF. meridionale\u3c/em\u3e CAUSING EAR AND STALK ROT OF MAIZE
Gibberella ear (GER) and stalk rot (GSR) diseases of maize in Brazil are caused mainly by Fusarium meridionale, a species belonging to the Fusarium graminearum species complex (FGSC). Another species within this complex, F. graminearum sensu stricto (hereafter F. graminearum), is second in importance on maize, but is the most common species found causing Fusarium Head Blight disease of wheat in Brazil. The latter species is the predominant cause of GER and GSR in North America, where F. meridionale has not been found thus far. In this dissertation I undertook a comparative analysis of pathogenic, saprophytic, toxigenic and genomic traits among a collection of strains representative of the two species and two hosts of origin to address possible explanations for the observed shift in the species dominance between maize and wheat. I initially hypothesized that the shift was due to their differential aggressiveness. To address this hypothesis, four field trials were conducted at different locations in order to study the aggressiveness (percent GER severity) of two F. meridionale and two F. graminearum strains, all isolated from maize, on maize hybrids with different levels of resistance. Plants were inoculated with single isolates, or with pairs of isolates sequentially and alternately at the silking stage. The results indicated that F. meridionale was more aggressive to maize than F. graminearum. Fusarium meridionale was also more competitive in ears that were co-inoculated with both species. In a second study I used a larger and more representative sample of strains of each species, isolated from both maize and wheat, to inoculate maize ears and stalks in the field. Consistent with my previous study, I found that F. meridionale was, on average, more aggressive than F. graminearum on maize ears. In contrast, F. graminearum was slightly more aggressive on maize stalks than F. meridionale. Both species contaminated maize ears with trichothecene mycotoxins, but F. graminearum strains produced primarily deoxynivalenol (DON) and its acetylated derivative 15ADON, whereas F. meridionale strains produced only nivalenol (NIV). The host of origin made no difference, and there was a lot of intraspecies variation in GER or GSR severity caused by isolates of both species. In a third study, an expanded collection of isolates of the two species was compared for 17 additional saprophytic, pathogenic, and toxigenic traits. Although there was significant intraspecies variation for most of these traits as well, the strains were strongly structured by species regardless of the host of origin, based on a multivariate analysis. Fusarium graminearum was a more aggressive pathogen of wheat, and produced primarily DON in rice cultures or in wheat heads. DON is known to be an important factor driving aggressiveness of F. graminearum in wheat. On the other hand, F. meridionale grew faster in culture. All F. meridionale strains produced mainly NIV both in vitro and in planta, with the exception of two strains from maize that produced more DON than NIV in wheat heads. In a fourth study, whole genome analysis of selected representatives of both species showed that they were genetically divergent, based on patterns of conservation of single-nucleotide polymorphisms (SNPs) across alignments. There was evidence of frequent outcrossing among strains within both species. The genome analysis also provided clear evidence of recombination between the two phylogenetic species, indicating that they are not genetically isolated, and thus belong to a single biological species. Genetic and phenotypic divergence of F. meridionale and F. graminearum may indicate adaptive selection to different environmental niches. The results of this study suggest differential aggressiveness and toxigenicity as partial explanations for the predominance of F. meridionale on maize and F. graminearum on wheat, and they lay a foundation for future studies to explore these associations
Healthcare gamification: Science mapping the body of literature
Healthcare gamification is a research topic being investigated in numerous contexts. As it is an interdisciplinary subject, it is hard for researchers to keep up with the research published in these venues. This paper aims to unveil the intellectual structure of the healthcare gamification research field through a systematic literature review. We apply a science map strategy to a 520- document database. This database was analyzed to build an evolutionary map revealing the most co-cited authors, their publications, and the theories used. Results evidence that referenced research can be classified into six research traditions. Finally, research opportunities are presented
La metamorfosis autopoiética de la vía emprendedora
It is essential to escape from the ignorance that we have created, for this reason the Via indicated by Edgar Morín (2011) is assumed. A new civilization is needed to achieve a better quality of life. It is observed how the existence of man is promoted through entrepreneurs. If entrepreneurship is done with community awareness, destination, productive, cultural and communicative processes develop on planet Earth in a rooted way. From this perspective, entrepreneurship in Latin America, technological adaptation, cultural autopoiesis as a way of transforming social systems in contemporary societies is approached
Evaluación de la Calidad del Paté Elaborado con Hígados de Diferentes Especies de Animales de Abasto 2011
La presente investigación se desarrollo en el centro de Producción de Cárnicos de la Facultad de Ciencias Pecuarias de la ESPOCH y tuvo como objetivo la evaluación de la calidad del paté con hígados de diferentes especies de animales de abasto. Se utilizaron hígados de res, cerdo y pollo y se diseño una formula de elaboración de paté única para las tres especies. Los patés elaborados, fueron sometidos a evaluación bromatológica, microbiológica y de aceptabilidad. Los resultados obtenidos, determinaron que el contenido grasa es muy alto por lo que su uso debe ser ocasional y en pequeñas cantidades. El pate que presenta mejor características sensoriales es el de pollo; los aportes de la proteína son inferiores a los que se reportan en hígados solo una razón de que en la formulación se utilizo 66.6 gr para cada 100 gr de pate. La elaboración del pate constituye una alternativa comercial para utilizar el hígado de animales comestibles.This research was developed in the center of meat production, Faculty of animal Science of the ESPOCH and aimed at the evaluation of the quality of liver pate with different species of animals for slaughter. Livers were used beef, pork y chicken and design a formula for making pate only for the three species. The elaborate pates underwent bromatological evaluation, microbiological and acceptability. The results, determined the fat content is very high so that its use should be occasional and in small quantities. The manhole provides the best sensory characteristics is the chicken, the contributions of the protein are lower than those reported in livers only one reason that the formulation was used in 66.6 gr per 100 gr of pate. The preparation of pate is a commercial alternative to using the liver of food animal
Short-and long-term exposure to heavy metals induced oxidative stress response in Pseudokirchneriella subcapitata
Algal cells can be exposed to toxicants for a short term due to accidental discharges or, more commonly, for a long term. The present work aimed to assess the ability of Cd, Cr, Cu and Zn to induce accumulation of reactive oxygen species (ROS) in the alga Pseudokirchneriella subcapitata after a short (6?h) or a long (72?h) exposure time. The relationship between the ROS induction and the content of reduced glutathione (GSH) was also examined. For this purpose, three nominal concentrations of each metal were used corresponding approximately to 72 h-EC10 and 72 h-EC50 values and a high concentration (>72 h-EC90 values). Intracellular ROS accumulation and GSH content were evaluated using a fluorescent-based approach. A long-term (chronic) exposure of algal cells to Cd, Cu and Zn, at the highest concentrations tested, induced an increase of intracellular ROS and GSH content. The increase of GSH content might be a form of algal cells to redress the imbalance caused by the oxidative stress. However, the increase of GSH was not enough to protect the algal cells against the long-term exposure to oxidative stress. The exposure of algal cells to low or intermediate metals concentrations induced a modification of GSH content; however, no increase of ROS production was detected, which indicates that the toxic symptoms exhibited by algal cells, under these conditions, cannot be attributed to intracellular ROS accumulation.This study was supported by the Portuguese Foundation for Science
and Technology (FCT) under the scope of the strategic founding of
UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-
006684), and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-
FEDER-027462). Manuela D. Machado gratefully acknowledges the
post-doctoral grant from FCT (SFRH/BPD/72816/2010)
Blood Vessels Under the Microscope
This paper looks at blood vessels. All humans and animals have blood vessels, including your pet rabbit or dog, a whale or a giraffe! We need blood vessels to stay alive. This paper answers many questions, including what blood vessels are used for and why we need them. It looks at how and why blood vessels grow and what they look like. It also explores what happens when things go wrong with blood vessels and if blood vessels are ever bad for us. So, if you want to know how many miles of blood vessels there are in your body, learn about problems astronauts have in space, see real blood vessels through a microscope, or learn how to keep your blood vessels healthy, you are reading the right article
Maternal environment on seed germination and viability in cowpea / Ambiente materno na germinação e viabilidade de sementes de feijão-caupi
Seed quality is determined by the environmental conditions to which they were exposed during their formation. Thus, the objective of this study was to evaluate the seed viability and seedling formation of cowpea cultivars produced in a high-temperature environment. Seeds of the cowpea cultivars Carijó, Itaim and Tapahium produced in growth chambers under temperature regimes T°1: 20-26-33 °C and T°2: 24.8-30.8-37.8 °C were used. The experimental design was completely randomized, with four replicates of 25 seeds, placed to germinate at a temperature of 25 °C in B.O.D chambers. Increase in air temperature during seed production did not hamper germination percentage. However, the 4.8 °C increase in air temperature reduced the vigor of seeds of the cultivar Tapahium, resulting in an increase in the number of abnormal seedlings. Seeds of the cultivars Carijó and Itaim produced under temperature regime 24.8-30.8-37.8 °C showed higher performance
Digital game for education and dissemination of nuclear energy applications
Students are immersed in a society with many possibilities of interaction, either computer or smart phones. In addition, students demand more innovation, dynamism and interactivity in classrooms. The form of education that can motivate students to engage in the learning process can get them to be interested in the lessons and not prematurely abandon schools. On the other hand, educational materials based on Virtual Reality (VR), as computer games, havebeen considered an important educational tool for making dynamic, motivating, innovative, in addition to achieving those areas where traditional methods are not reaching its goal. Motivated by the above, and given the competence developed by the Virtual Reality Laboratory of the Instituto de Engenharia Nuclear / CNEN and the collaboration of the University Center UniCarioca, was developed a digital game based on virtual reality tools for the teaching of a subject of area of science that needs to be addressed to society more contextualized way: the different applications of nuclear energy. It is expected that this digital game is an important tool for the dissemination, teaching and learning the benefits of nuclear energy
Use of a fluorescence-based approach to assess short-term responses of the alga Pseudokirchneriella subcapitata to metal stress
This work explores the use of fluorescent probes to evaluate the responses of the green alga Pseudokirchneriella subcapitata to the action of three nominal concentrations of Cd(II), Cr(VI), Cu(II) and Zn(II) for a short time (6 h). The toxic effect of the metals on algal cells was monitored using the fluorochromes SYTOX Green (SG, membrane integrity), fluorescein diacetate (FDA, esterase activity) and rhodamine 123 (Rh123, mitochondrial membrane potential). The impact of metals on chlorophyll a (Chl a) autofluorescence was also evaluated. Esterase activity was the most sensitive parameter. At the concentrations studied, all metals induced the loss of esterase activity. SG could be used to effectively detect the loss of membrane integrity in algal cells exposed to 0.32 or 1.3 mol L1 Cu(II). Rh123 revealed a decrease in the mitochondrial membrane potential of algal cells exposed to 0.32 and 1.3 mol L1 Cu(II), indicating that mitochondrial activity was compromised. Chl a autofluorescence was also affected by the presence of Cr(VI) and Cu(II), suggesting perturbation of photosynthesis. In conclusion, the fluorescence-based approach was useful for detecting the disturbance of specific cellular characteristics. Fluorescent probes are a useful diagnostic tool for the assessment of the impact of toxicants on specific targets of P. subcapitata algal cells.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Manuela D. Machado gratefully acknowledges the post-doctoral grant from FCT (SFRH/BPD/72816/2010)
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