1,284 research outputs found

    Genetic diversity of the sunflower caterpillar (Chlosyne lacinia saundersii Doubleday and Hewitson) ( Lepidoptera: Nymphalidae) populations determined by molecular RAPD markers.

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    Chlosyne lacinia saundersii is one of the most important pests of sunflower and it is the main target of insecticides applications. Larvae were collected in Londrina (PR), Santa Maria (RS), Dourados (MS), Ribeirão Preto (SP), Brasília (DF), Barreiras (BA), Uberaba (MG) and Vilhena (RO). Genomic DNA was extracted and amplified with ten-mer primers, which produced 101 loci. The size of the RAPD amplicons ranged from 180 to 2564 bp. Polymorphism among populations ranged from 31% to 67%, with the highest polymorphisms of 57% and 67% being detected in Uberaba and Vilhena populations, respectively. Populations with the highest similarity determined with Dice coefficient were from Ribeirão Preto and Barreiras, while insects from Londrina showed the highest similarity among them. Gene flow of C. lacinia saundersii 1.1 was lower than those previously observed for the noctuid Anticarsia gemmatalis Hübner, suggesting that C. lacinia saundersii populations are more isolated than the ones of this noctuid. Through the Analysis of Molecular Variance (AMOVA), RAPD variance was 33.64% among geographical populations and 66.36% within populations. These results suggest that populations of C. lacinia saundersii are genetically structured

    Inactivation of Geobacillus stearothermophilus spores by alkaline hydrolysis applied to medical waste treatment

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    Although alkaline hydrolysis treatment emerges as an alternative disinfection/sterilization method for medical waste, information on its effects on the inactivation of biological indicators is scarce. The effects of alkaline treatment on the resistance of Geobacillus stearothermophilus spores were investigated and the influence of temperature (80 degrees C, 100 degrees C and 110 degrees C) and NaOH concentration was evaluated. In addition, spore inactivation in the presence of animal tissues and discarded medical components, used as surrogate of medical waste, was also assessed. The effectiveness of the alkaline treatment was carried out by determination of survival curves and D-values. No significant differences were seen in D-values obtained at 80 degrees C and 100 degrees C for NaOH concentrations of 0.5 M and 0.75 M. The D-values obtained at 110 degrees C (2.3-0.5 min) were approximately 3 times lower than those at 100 degrees C (8.8-1.6 min). Independent of the presence of animal tissues and discarded medical components, 6 log10 reduction times varied between 66 and 5 min at 100 degrees C-0.1 M NaOH and 110 degrees C-1 M NaOH, respectively. The alkaline treatment may be used in future as a disinfection or sterilization alternative method for contaminated waste

    Optimizing potentiometric ionophore and electrode design for environmental on-site control of antibiotic drugs: Application to sulfamethoxazole

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    Potentiometric sensors are typically unable to carry out on-site monitoring of environmental drug contaminants because of their high limits of detection (LODs). Designing a novel ligand material for the target analyte and managing the composition of the internal reference solution have been the strategies employed here to produce for the first time a potentiometric-based direct reading method for an environmental drug contaminant. This concept has been applied to sulfamethoxazole (SMX), one of the many antibiotics used in aquaculture practices that may occur in environmental waters. The novel ligand has been produced by imprinting SMX on the surface of graphitic carbon nanostructures (CN) < 500 nm. The imprinted carbon nanostructures (ICN) were dispersed in plasticizer and entrapped in a PVC matrix that included (or not) a small amount of a lipophilic additive. The membrane composition was optimized on solid-contact electrodes, allowing near-Nernstian responses down to 5.2 μg/mL and detecting 1.6 μg/mL. The membranes offered good selectivity against most of the ionic compounds in environmental water. The best membrane cocktail was applied on the smaller end of a 1000 μL micropipette tip made of polypropylene. The tip was then filled with inner reference solution containing SMX and chlorate (as interfering compound). The corresponding concentrations were studied for 1 × 10−5 to 1 × 10−10 and 1 × 10−3 to 1 × 10−8 mol/L. The best condition allowed the detection of 5.92 ng/L (or 2.3 × 10−8 mol/L) SMX for a sub-Nernstian slope of −40.3 mV/decade from 5.0 × 10−8 to 2.4 × 10−5 mol/L

    High performance free-standing films by layer-by-layer assembly of graphene flakes and ribbons with natural polymers

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    In this work, novel free-standing (FS) films based on chitosan, alginate and graphene oxide (GO) were developed through layer-by-layer assembly. First, GO was synthesized from graphite and multi-walled carbon nanotubes using a modified Hummer's method, yielding oxidized graphene flakes (o-GFs) and oxidized graphene nanoribbons (o-GNRs), respectively, which were then characterized. Then FS films were produced and their morphological, thermal and mechanical properties, as well as the o-GF and o-GNR dispersion along the films were assessed. Their degradation and swelling profiles as well as their biological behavior were evaluated. Graphite and nanotubes were successfully oxidized and exfoliated forming stable suspensions that could be combined with chitosan (CHI) and alginate (ALG) solutions by layer-by-layer processing. The addition of o-GFs and o-GNRs resulted in rougher, hydrophilic FS films with significantly improved mechanical properties relative to CHI/ALG films. The presence of o-GFs or o-GNRs did not affect the thermal stability and the addition of o-GFs resulted in films with enhanced cytocompatibility. The results demonstrate the high potential of the GO reinforced films for biomedical applications, in particular o-GF films, for wound healing, and cardiac and bone engineering applications.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) and the European program FEDER/ COMPETE for the financial support through project BioSeaGlue: EXPL/CTM-BIO/0646/2013 (FCOMP-01-0124-FEDER-041105) and for project PEst-C/CTM/LA0025/2013 (Strategic Project – LA 25 – 2013-2014). This work was also financially supported by FCT through the scholarships SFRH/BPD/96797/2013 granted to Sofia G. Caridade, SFRH/BD/97606/2013 granted to Maria Sousa, and SFRH/BD/87214/2012 granted to Eunice Cunha

    Leaf Epidermal Descriptors of Forage from Caatinga, NE Brazil

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    In the Brazilian semi-arid region, the predominant vegetation is the Caatinga, which has a diversity of plant species, some endemic and presenting forage potential. The characterization of the plant anatomy is important for animal diet studies, using a microhistological technique (Scott and Dahl 1980) for estimating the diet botanical composition from ruminant faeces. This paper determined leaf epidermal descriptors for Caatinga species using microscopic slides

    The second International Symposium on Fungal Stress: ISFUS

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    The topic of ‘fungal stress’ is central to many important disciplines, including medical mycology, chronobiology, plant and insect pathology, industrial microbiology, material sciences, and astrobiology. The International Symposium on Fungal Stress (ISFUS) brought together researchers, who study fungal stress in a variety of fields. The second ISFUS was held in May 8-11 2017 in Goiania, Goiás, Brazil and hosted by the Instituto de Patologia Tropical e Saúde Pública at the Universidade Federal de Goiás. It was supported by grants from CAPES and FAPEG. Twenty-seven speakers from 15 countries presented their research related to fungal stress biology. The Symposium was divided into seven topics: 1. Fungal biology in extreme environments; 2. Stress mechanisms and responses in fungi: molecular biology, biochemistry, biophysics, and cellular biology; 3. Fungal photobiology in the context of stress; 4. Role of stress in fungal pathogenesis; 5. Fungal stress and bioremediation; 6. Fungal stress in agriculture and forestry; and 7. Fungal stress in industrial applications. This article provides an overview of the science presented and discussed at ISFUS-2017.Sao Paulo Research Foundation (FAPESP) 2010/06374-1, 2013/50518-6, 2014/01229-4Brazilian National Council for Scientific and Technological Development (CNPq) PQ2 302312/2011-0, PQ1D 308436/2014-8Coordenação de Aperfeiçoãmento de Pessoal de Nível Superior (CAPES) PAEP 88881.123209/2016-01Fundação de Amparo à Pesquisa do Estado de Goiás Brazil 20171026700011

    Relationship between Field Measurements in Three \u3cem\u3eBrachiaria\u3c/em\u3e Species with Leaf Area Index and Light Interception by Indirect Methods

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    Brachiaria species play a strategic role in ruminant production systems in Brazil, covering an estimated pasture area of approximately 90 million hectares (Karia et al., 2006), however, these pastures are subject to different degrees of degradation due to inadequate management. In pasture management, field measurements such as canopy height, for example, are used by managers as a tool to establish parameters for the optimal point to cut the forage and for the post-grazing residue, in order to maximize production by harvesting at maximum of herbage mass accumulation, and to avoid problems associated to overgrazing, by setting ideal post-grazing height for forage regrowth. The use of the variables light interception (LI) and leaf area index (LAI) has been recommended as a tool for pasture management, based on the theory that, when the canopy reaches a light interception of 95%, the forage is near its maximum growth rate, which is called critical LAI (Brougham, 1956). The residual LAI refers to the leaf area of the post-grazed stubble. Residual LAI is used to establish the minimum leaf area necessary to ensure an efficient pasture regrowth (Lemos et al., 2014). Light interception and the LAI are difficult to measure at the farm level, due to the high cost of the equipment and technical feasibility of the process. The objective of this study was to evaluate the relationship between LI and LAI measured by two different equipment, with canopy height and soil cover in three species of Brachiaria

    Adaptability and Stability of Productive Characteristics on the Selection of Pennisetum purpureum Schum. Clones Grazed by Sheep

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    Elephant grass (Pennisetum purpureum Schum.) is one of the most widely used forages in Brazil, due to its high potential productivity, forage quality, palatability, vigour and persistence. Dwarf types of elephant grass are the object of selection programs for their higher leaf/stem ratio and lower grazing height, resulting in more efficient pasture management. They have high potential for ruminant production (Almeida et al. 2000), but have markedly different morphological and productive characteristics (Cunha et al. 2011) to tall varieties of the same species. Adaptability and stability analyses are selection tools which allow identification of plant responses to different environments (Cruz and Regazzi 2001) and can identify stable productive clones across a range of environments. This study evaluated the genotype x environment interaction for productive characteristics of P. purpureum clones grazed by sheep
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