238 research outputs found

    Prediction of genotypic values of maize for the agricultural frontier region in northeastern Maranhao, Brazil

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    Mora, F (Mora, Freddy). Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, ChileAgricultural research, mainly focused on the evaluation of maize cultivars along agricultural frontiers, are scarce. This study assessed 128 maize genotypes in the agricultural frontier region of the State of Maranhao, between 2008 and 2009. The experiment was arranged in a lattice design with two replications. The genotypes were evaluated for grain yield in a mixed model, with fixed intercept and experimental effects. The random effects were genotype, genetic class (single-, double or triple-cross hybrid and variety), and incomplete block/replication/environment. The genotype effect was significant by the likelihood ratio test in all models, highlighting the genotypic values of the single-cross hybrids DKB177, AG8088 and DKB390, the triple-cross PL6882, the double-cross BM502 and of the open-pollinated variety SHS3031

    Free heme and amyloid-β: a fatal liaison in Alzheimer's disease

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    While the etiology of Alzheimer's disease (AD) is still unknown, an increased formation of amyloid-β (Aβ) peptide and oxidative processes are major pathological mechanism of the disease. The interaction of Aβ with free heme leads to the formation of peroxidase-active Aβ-heme complexes. However, enzyme-kinetic data and systematic mutational studies are still missing. These aspects were addressed in this study to evaluate the role of Aβ-heme complexes in AD. The enzyme-kinetic measurements showed peroxidase-specific pH- and H2O2-dependencies. In addition, the enzymatic activity of Aβ-heme complexes constantly increased at higher peptide excess. Moreover, the role of the Aβ sequence for the named enzymatic activity was tested, depicting human-specific R5, Y10, and H13 as essential amino acids. Also by studying Y10 as an endogenous peroxidase substrate for Aβ-heme complexes, ratio-specific effects were observed, showing an optimal dityrosine formation at an about 40-fold peptide excess. As dityrosine formation promotes Aβ fibrillation while free heme disturbs protein aggregation, we also investigated the effect of Aβ-heme complex-derived peroxidase activity on the formation of Aβ fibrils. The fluorescence measurements showed a different fibrillation behavior at strong peroxidase activity, leading also to altered fibril morphologies. The latter was detected by electron microscopy. As illustrated by selected in vivo measurements on a mouse model of AD, the disease is also characterized by Aβ-derived microvessel destructions and hemolytic processes. Thus, thrombo-hemorrhagic events are discussed as a source for free heme in brain tissue. In summary, we suggest the formation and enzymatic activity of Aβ-heme complexes as pathological key features of AD.Solid state NMR/Biophysical Organic Chemistr

    Manual and automated blood cells count in ocelots (Leopardus pardalis - Linnaeus, 1758)

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    Aparelhos de automação, cujo uso está estabelecido na hematologia dos animais domésticos, ainda não são empregados rotineiramente em felídeos selvagens. Esse estudo objetivou avaliar a técnica automatizada na contagem de células sanguíneas de jaguatiricas (Leopardus pardalis), comparando-a com a técnica manual. Foram coletadas amostras sanguíneas de oito jaguatiricas, que se submeteram à contagem de eritrócitos, leucócitos, plaquetas e à determinação do volume globular pelo método manual padrão e por meio do aparelho BC - 2800 VET® com a configuração para gatos domésticos. Os resultados foram avaliados por meio do teste t para dados pareados, e as técnicas submetidas à análise de correlação de Pearson. A técnica automatizada demonstrou resultados estatisticamente semelhantes para eritrócitos e leucócitos. Apenas para volume globular houve diferença significativa entre as técnicas manual e automatizada, mas a correlação foi alta. Apesar de não haver diferença significativa entre as técnicas para plaquetas, a correlação foi baixa. Conclui-se que o aparelho BC - 2800 VET® com a configuração para gatos domésticos é uma técnica confiável na realização do eritrograma e do leucograma para jaguatiricas. Para a determinação do parâmetro volume globular, o aparelho pode ser utilizado, desde que se faça a correção. Para a contagem de plaquetas, a técnica manual é recomendada.Automated equipment, whose use is established in hematology of domestic animals, is not yet routinely used in blood cells count of wildlife, due to lack of studies that validate its use. The purpose of this study was to evaluate the automated technique for blood cells count of ocelots (Leopardus pardalis), comparing it with the manual technique. Blood samples were collected from eight ocelots, which were submitted to counting of erythrocytes, leukocytes, platelets and packed cell volume by the standard manual method and by the device VET ® 2800 BC with the configuration for domestic cats. The results were evaluated using the t test for paired data and the techniques submitted to Pearson correlation. The automated technique showed statistically similar results to erythrocytes and leukocytes. Significant difference was found only for packed cell volume between the manual and automated techniques, but the correlation was high. Although there was no significant difference between the techniques for platelets, the correlation was low. We concluded that the 2800 BC VET ® device with the configuration for domestic cats is a reliable technique in performing the erythrocyte and leukocyte counts for ocelots. The device may be used to determine packed cell volume, provided the correction is made. The manual technique is recommended for the platelet count

    Avaliação fenotípica qualitativa como critério para implantação de programas de acasalamentos em rebanhos da raça Curraleiro Pé-Duro.

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    Objetivou-se com este estudo implantar programas de acasalamentos em rebanhos de bovinos da raça Curraleiro Pé-Duro, utilizando a avaliação fenotípica como principal critério de seleção, com vistas à conservação destes recursos genéticos animais. Foram avaliadas características fenotípicas de 180 animais da raça Curraleiro Pé-Duro em duas explorações, com o objetivo de comprovar a existência de similaridade e dissimilaridade entre eles, para orientar futuros acasalamentos. Para obter a matriz de dissimilaridade e o dendrograma o coeficiente de Jaccard. Nas duas explorações observou-se que alguns reprodutores não apresentaram dissimilaridade e que outros apresentaram pouca dissimilaridade em relação às fêmeas. Entretanto algumas fêmeas demonstraram ser dissimilares a vários machos. O programa de acasalamentos sugerido para cada exploração contou com a divisão do rebanho em lotes, rodízios de reprodutores e a troca de touros pouco dissimilares por outros touros de rebanhos diferentes, visando aumentar a variabilidade genética dos rebanhos

    Spatial distribution and evaluation of risk factors for bovine neosporosis in Rondônia, Brazil

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    ABSTRACT Neospora caninum is an important worldwide parasite responsible for causing abortion in animals. Due to limited information on the occurrence of infection by this parasite in the state of Rondônia, Brazil, this study aimed to determine the seroprevalence and identify the risk factors associated with the infection in slaughtered cattle, from 19 municipalities distributed in seven microregions of the state. A total of 494 samples were obtained and subjected to anti-N. caninum antibodies, using the Indirect Immunofluorescence Reaction technique. Antibodies were detected in 5.06% (25/494) of the samples, in 30.30% (10/33) of farms, in nine municipalities located in four microregions of Rondônia. Of all the animals analyzed, 4.81% of the females (20/416) and 6.41% of the males (05/78) were seropositive for the parasite, with “abortion in the last 12 months” being considered an important risk factor for the occurrence of infection (OR = 9.54; p = 0.01). The present study points out the prevalence of anti-N. caninum antibodies in 5.06% of slaughtered animals and abortion as the main risk factor associated with infection by N. caninum, thus contributing to the elucidation of the epidemiology of this protozoan in Rondônia, Brazil
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