1,254 research outputs found

    Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)

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    ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence. Key words: Molecular markers; VNTRs; Genetic diversity; Population genetics; Black Sigatok

    Multivariate Study Of Nile Tilapia Byproducts Enriched With Omega-3 And Dried With Different Methods

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    The present work aimed at studying the effect of different drying methods applied to tilapia byproducts (heads, viscera and carcasses) fed with flaxseed, verifying the contents of omega-3 fatty acids. Two diets were given to the tilapia: a control and a flaxseed formulation, over the course of 60 days. After this period, they were slaughtered and their byproducts (heads, viscera and carcasses) were collected. These fish parts were analyzed in natura, lyophilized and oven dried. Byproducts from tilapia fed with flaxseed presented docosapentaenoic, eicopentaenoic and docosahexanoic fatty acids as a result of the enzymatic metabolism of the fish. The byproducts from the oven drying process had lower levels of polyunsaturated fatty acids. In the multivariate analysis, the byproducts from fish fed with flaxseed had a greater composition of fatty acids. The addition of flaxseed in fish diets, as well as the utilization of their byproducts, may become a good business strategy. Additionally, the byproducts may be dried to facilitate transport and storage. © 2016 Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA. All rights reserved.361182

    Genetic Divergence Among Accessions Of Cassava (manihot Esculenta Crantz) Sampled In The Tapajós Region, State Of Pará, Using Agronomic Characters And Microsatellite Markers

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    The aim of this work was to estimate the genetic divergence among accessions of cassava sampled in the Tapajós region in the State of Pará, Brazil, and conserved at the Regional Germplasm Bank of Eastern Amazon, using agronomic descriptors and molecular markers. Twenty-two accessions of cassava were evaluated in the field for two successive years, based on six agronomic descriptors in twelve-months-old plants without a specific experimental design. Accessions were also evaluated with eleven microsatellite loci in an automatic DNA analyser. Descriptive and multivariate statistical analyses were applied. Based on principal components analysis, the character weight of the aerial portion of the plant contributed most to the phenotypical variation. The six traits were used in the analysis of genetic dissimilarity between accessions, and the correlation between matrices generated by morphological and molecular data was estimated. The matrices of genetic dissimilarity were used in the construction of dendrograms using the UPGMA method. We observed a high variation of agronomical descriptors and molecular markers evaluated, which were capable to separate the accessions into distinct groups. A weak positive correlation was detected among the two matrices of genetic distances, which indicates the possibility to explore the genetic diversity using crossings and accessions Amarelinha 36 and Olho roxo 13 are divergent and potentially promising for the generation of heterotic hybrids.3752989300

    Infestação pré-histórica por Pediculus humanus capitis: análise quantitativa e por microscopia de varredura de baixo vácuo

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    A pre-Columbian Peruvian scalp was examined decades ago by a researcher from the Oswaldo Cruz Foundation. Professor Olympio da Fonseca Filho described nits and adult lice attached to hair shafts and commented about the origin of head lice infestations on mankind. This same scalp was sent to our laboratory and is the subject of the present paper. Analysis showed a massive infestation with nine eggs/cm2 and an impressive number of very well preserved adult lice. The infestation age was roughly estimated as nine months before death based on the distance of nits from the hair root and the medium rate of hair growth. A small traditional textile was associated with the scalp, possibly part of the funerary belongings. Other morphological aspects visualized by low-vacuum scanning electron microscopy are also presented here for adults and nits.Há décadas um escalpo peruano, datado do período pré-colombiano, foi examinado por um pesquisador da Fundação Oswaldo Cruz. O Professor Olympio da Fonseca Filho descreveu lêndeas e adultos fixos a fios de cabelos e fez comentários sobre a origem da infecção por piolhos na espécie humana. Este mesmo escalpo foi enviado ao nosso laboratório e é objeto deste artigo. Sua análise mostrou maciça infestação, com nove lêndeas/cm2 em impressionante número de adultos muito bem preservados. O tempo de infestação foi estimado em cerca de nove meses antes da morte, baseado na maior distância entre lêndeas e o couro cabeludo, levando em consideração taxa média de crescimento capilar de 1 cm por mês. Um pequeno pedaço de tecido tradicional peruano foi encontrado associado ao escalpo, provavelmente pertencente ao conjunto de peças usado no ritual funerário. Aqui, apresentamos alguns aspectos morfológicos de adultos e lêndeas vizualizados por microscopia eletrônica de varredura de baixo vácuo

    Avaliação Da Assistência Oftalmológica Na Perspectiva Dos Usuários

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    The prevalence of need of, access to, and dissatisfaction with ophthalmic assistance was estimated among those who were assisted in such services in the last year; factors associated with dissatisfaction were identified. Complex probabilistic sample was used. A descriptive, bivariate, and multiple analysis with correction for design effect was conducted. Of 2.582 participants, 76% needed assistance and, of those, 82.5% possessed access to it. Among patients who received assistance in the last year, 13.1% were dissatisfied. Dissatisfaction was higher among older patients, those who went walking or cycling to the location of assistance, and those who described the following aspects as regular/bad/terrible: being received and treated with respect, the clarity with which the service provider explained things, and their autonomy to choose their provider of ophthalmic assistance. Most of them was in need of and possessed access to assistance. Dissatisfaction was low. Patient’s age, means of transport used to get to the local of the assistance, patient-professional relationship, and autonomy to choose are factors that interfere for the outcome of dissatisfaction. © 2016, Assocaicao Brasileira de Pos, Gradacao em Saude Coletiva. All rights reserved.19239040

    Hidrogenionic potential (pH) of the attractant, trap density and control threshold for Ceratitis capitata (Diptera: tephritidae) on Hamlin oranges in São Paulo central region, Brazil

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    This study evaluated the effect of initial pH values of 4.5, 6.5 and 8.5 of the attractant (protein bait) Milhocina® and borax (sodium borate) in the feld, on the capture of fruit flies in McPhail traps, using 1, 2, 4 and 8 traps per hectare, in order to estimate control thresholds in a Hamlin orange grove in the central region of the state of São Paulo. The most abundant fruit fly species was Ceratitis capitata, comprising almost 99% of the fruit flies captured, of which 80% were females. The largest captures of C. capitata were found in traps baited with Milhocina® and borax at pH 8.5. Captures per trap for the four densities were similar, indicating that the population can be estimated with one trap per hectare in areas with high populations. It was found positive relationships between captures of C. capitata and the number of Hamlin oranges damaged, 2 and 3 weeks after capture. It was obtained equations that correlate captures and damage levels which can be used to estimate control thresholds. The average loss caused in Hamlin orange fruits by C. capitata was 2.5 tons per hectare or 7.5% of production.Esta pesquisa teve como objetivos: avaliar o efeito do pH inicial, 4.5; 6.5 e 8.5, do atrativo proteico Milhocina® e bórax (tetraborato de sódio) na captura de moscas-das-frutas em armadilhas McPhail; estudar densidades de armadilhas, 1; 2; 4 e 8 por hectare, para estimar níveis de controle em laranja cv. Hamlin, na região central de São Paulo. A espécie predominante, com 99% das moscas-das-frutas capturadas, foi Ceratitis capitata, sendo 80% de fêmeas. As maiores capturas de C. capitata ocorreram nas armadilhas com Milhocina® e bórax em pH 8.5. As capturas, nas 4 densidades, foram semelhantes, indicando que a população pode ser estimada com uma armadilha por hectare em áreas de altas populações. Houve relações positivas entre capturas de C. capitata e o número de frutos danificados, 2 e 3 semanas após a captura. Assim, foram obtidas equações que relacionam a captura e o dano, possibilitando estimar níveis de controle desse inseto. As perdas médias causadas por C. capitata em laranja cv. Hamlin chegaram a 2,5 toneladas de frutos por hectare ou 7,5% da produção.info:eu-repo/semantics/publishedVersio

    Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems

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    A transfer matrix scaling technique is developed for randomly diluted systems, and applied to the site-diluted Ising model on a square lattice in two dimensions. For each allowed disorder configuration between two adjacent columns, the contribution of the respective transfer matrix to the decay of correlations is considered only as far as the ratio of its two largest eigenvalues, allowing an economical calculation of a configuration-averaged correlation length. Standard phenomenological-renormalisation procedures are then used to analyse aspects of the phase boundary which are difficult to assess accurately by alternative methods. For magnetic site concentration pp close to pcp_c, the extent of exponential behaviour of the Tc×pT_c \times p curve is clearly seen for over two decades of variation of p−pcp - p_c. Close to the pure-system limit, the exactly-known reduced slope is reproduced to a very good approximation, though with non-monotonic convergence. The averaged correlation lengths are inserted into the exponent-amplitude relationship predicted by conformal invariance to hold at criticality. The resulting exponent η\eta remains near the pure value (1/4) for all intermediate concentrations until it crosses over to the percolation value at the threshold.Comment: RevTeX 3, 11 pages +5 figures, uuencoded, to appear in Phys. Rev. B (1994), PUC/RJ preprin

    Cellulose nanocrystal-based poly(butylene adipate-co-terephthalate) nanocomposites covered with antimicrobial silver thin films

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    In this study, we reported the preparation and prospective application of the nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) reinforced with cellulose nanocrystals (CNCs). CNCs were isolated from bleached sugarcane bagasse by acid hydrolysis and functionalized with adipic acid. Nanocomposites were prepared with different concentration of CNCs (0.8, 1.5, and 2.3 wt% CNC) by solution-casting method and then were covered with silver thin film by magnetron sputtering. The results showed that the surface modification increased the degree of crystallinity of nanocrystals from 51% to 56%, decreasing their length and diameter. Moreover, AFM-IR spectroscopy revealed that the modified CNCs were covered by adipic acid molecules, improving the dispersion of nanocrystals in PBAT. Well-dispersed modified CNCs acted as heterogeneous nuclei for crystallization of PBAT, and increased the storage modulus of the polymer by more than 200%. These improvements in thermal and mechanical properties of CNC-based PBAT associated with the decrease of 56% in the Escherichia coli biofilm formation on nanocomposites (antibacterial properties) qualify the CNC/PBAT nanocomposites covered with silver thin films to be used as food packaging. POLYM. ENG. SCI., 59:E356-E365, 2019. (c) 2019 Society of Plastics Engineers59s22E356E365CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoNÃO CONSTANÃO CONSTA2016/09588-9CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paul

    Variables associated with the tolerance to water deficit in forage grasses

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    Avaliou-se, sob condições de campo, a tolerância ao déficit hídrico de quatro gramíneas forrageiras. Determinaram-se o potencial hídrico da folha, a resistência estomática, a altura dos perfilhos e o comprimento do limbo foliar do capim-carimagua (Andropogon gayanus), capim-bufel (Cenchrus ciliaris) cvs. Gayndah e Biloela, e quicuio-da-amazônia (Brachiaria humidicola). Os capins carimagua, 'Gayndah' e 'Biloela' sob regime seco, não atingiram um valor crítico de potencial hídrico da folha para o fechamento estomático. O capim quicuio-da-amazônia atingiu mais baixo potencial hídrico da folha (-21 bares) e mais alta resistência estomática (20 seg.cm-1) em relação aos demais capins estudados neste trabalho. Com relação a altura do perfilho e comprimento do limbo foliar, os capins carimagua, 'Gayndah' e 'Biloela' também se comportaram como mais tolerantes ao déficit hídrico. Dessa forma, os capins carimagua, 'Gayndah' e 'Biloela' são opções mais seguras para as áreas onde ocorrem estiagens de mais de 120 dias.The tolerance to water deficit of four tropical grasses was evaluated under field conditions. The leaf water potential, stomatal resistance, sprout height and leaf blade length were determined for Carimagua grass (Andropogon gayanus) buffel grass (Cenchrus ciliaris) cvs. Gayndah and Biloela, and Brachiaria Amazonian kikuyo grass (Brachiaria humidicola). The carimagua, 'Gayndah' and Biloela' grasses, under water deficit conditions, did not attain the critical level of leaf water potential for stomatal closing. The Amazonian kikuyo grass attained the lowest leaf water potential (-21 bars) and greatest diffusive stomatal resistance (20 seg. Cm-1) of the grasses studied here. The carimagua 'Gayndah' and 'Biloela' grasses also demonstrated, in relation to sprout height and leaf blade length, greater tolerance to water deficit than Amazonian kikuyo grass. Hence, the carimagua, 'Gayandah' and Biloela' grasses are a choice for areas where drought occurs for more than 120 days
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