270 resultados para Seleção clonal


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Enteropathogenic Escherichia coli ( EPEC) strains are important agents of infantile diarrhea all over the world, gaining even greater importance in developing countries. EPEC have also been isolated from various animal species, but most isolates belong to serotypes that differ from those recovered from humans. However, it has been demonstrated that several isolates from non- human primates belong to the serogroups and/ or serotypes related to those implicated in human disease. The objective of this study was to evaluate the genetic differences between thirteen strains isolated from non- human primates and the same number of strains isolated from human infections. Human isolates belonged to the same serogroup/ serotype as the monkey strains and the evaluation was done by analysis of random amplified polymorphic DNA. Dendrogram analysis showed that there was no clustering between human and monkey strains. Human and non- human isolates of the EPEC serotypes O127:H40 and O128:H2 shared 90 and 87% of their bands, respectively, indicating strong genomic similarity between the strains, leading to the speculation that they may have arisen from the same pathogenic clone. To our knowledge, this study is the first one comparing genomic similarity between human and non- human primate strains and the results provide further evidence that monkey EPEC strains correlate with human EPEC, as suggested in a previous investigation.

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The objectives of this study were to obtain heritability and genetic, phenotypic and environmental correlation estimates for birth (B), weaning (WW), yearling (YW) and 18 - (EW) and 24 - month (TW) weights, and to propose selection criteria for body weight in Canchim cattle. The data were analyzed by the least-squares method with models that included the fixed effects of herd, year and month of birth, sex of calf and age of cow at calving, and the random effects of sire within herd. The heritability estimates obtained were equal to 0.36 0.06 (BW), 0.47 0.06 (WW), 0.53 0.07 (YW), 0.54 0.08 (EW) and 0.27 0.06 (TW). The genetic correlations were equal to 0.51 (BW and WW), 0.36 (BW and YW), 0.14 (BW and EW), 0.00 (BW and TW), 0.92 (WW and YW), 0.77 (WW and EW), 0.75 (WW and TW), 0.94 (YW and EW), 0.86 (YW and TW) and 0.85 (EW and TW). The phenotypic correlations ranged from 0.19 to 0.72, and the environmental correlations from 0.11 to 0.61. The results showed that, in general, mass selection for weight will result in genetic progress, selection for weight at any age will result in correlated changes at other ages, and EW and TW are good selection criteria for increasing weight in the Canchim breed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The genetic relatedness among 96 invasive Escherichia coli belonging to several serogroups and 13 non-invasive of several serotypes that share the same O antigen was investigated by multilocus enzyme electrophoresis analysis. The invasive strains were isolated in different parts of the world and most of them recovered from dysentery. Twenty-nine electrophoretic types were distinguished and the most invasive strains were found to belong to two major lineages. These results suggested that the invasive ability in these strains has evolved in divergent chromosomal backgrounds, presumably through the horizontal spread of plasmid-borne invasion genes. The maintenance of invasive phenotypes in separate lineages suggests that this ability confers a selective advantage to invasive strains. Copyright (C) 1999 Federation of European Microbiological Societies.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Individual data of basic density and volume of wood, pulp kappa number, soluble lignin, cost of pulping process as well as gravimetric gross yield of pulping process were used from 64 trees of Eucalyptus grandis W. Hill ex Maiden from a commercial population at Lençóis Paulista, SP. The Eucalyptus grandis's seeds were originally from a Seed Production Area (SPA) of Duratex S/A at Botucatu, SP. Obtained data were quantified considering objective of maximization no-bleaching pulp and volume and mass wood restriction, mass of residual and soluble lignin, planted area and pulping process cost. it has also been aimed a selection method for matrix trees through mathematical programming techniques. Obtained strategy maximized the economical result, selected matrix trees and followed all limits of technological and organizing productivities imposed by the company. It also aimed the production of no-bleaching pulp within the planned time.

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Curcuma longa L. is used in many countries for its flavor, and medicinal and cosmetic attributes, as well as for its peculiar starch characteristics. These factors have driven an interest in the in vitro propagation of this species, looking for germplasm bank maintenance, production of disease free plants, genetic variability induction from callus, and as a tool for starch research. However, there are few reports concerning the micropropagation of Curcuma longa. The in vitro propagation rate of this species, cultured under two benzylaminopurine (BAP) concentrations, was the aim of this research.

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In breeding programs, the complexity of economically outstanding characters, most of which highly influenced by the environment, makes selection difficult. Using genetic parameters, like heritability and gain with selection, it is possible to identify superior genotypes in early generations. Therefore, the aim of the present research was to compare different selection criteria by the estimated gains and the selected progenies, determining the superior and more similar methods. Augmented block design was used with three additional checks. Twelve hundred genotypes were evaluated. The most expressive expected gains were obtained with direct selection. However, the indices have shown to be more appropriate for selecting superior progenies because of their higher total gains, distributed among all the evaluated characters. The Sum of Ranks Index allowed the highest gains in most of the situations analysed.

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Historically, the incorrect waste disposal has been related to epidemics which resulted in thousand of deaths. Despite the efforts to develop sanitary disposal methods in the 19 century, even today, uncontrolled dumps are often found in undeveloped countries. These places are responsible for environment pollution and for several diseases. The process of adequate waste disposal begins with the selection of suitable landfill areas, based on environmental characteristics. The goal of this research was to compare two methods of landfill site selection: the first one developed by IG-SMA (1999), and the other by Basílio (2001). Both methods were developed and applied in the same area - region of Campinas, São Paulo State, Brazil and this fact explains the choice for them; the comparison was made by superposing maps. Despite the same geographic area, the result was very different and few areas in common were found; IG-SMA (1999) obtained more suitable areas than Basílio (2001). This has been attributed to scale, criteria and attribute differences and, as a conclusion, Basílio (2001) was considered more restrictive than IG-SMA (1999).

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Clinical studies on nasal topical medications require the standardization of nasosinusal normality in order to establish control groups through a specific evaluation of the upper airways. Aim: to standardize the evaluation of candidates for control groups in clinical studies on nasal topical medications. Material and Methods: healthy male volunteers of 18 to 50 years of age, asymptomatic from the nasosinusal standpoint were subjected to a sequential and excluding assessment made up of clinical evaluation, immediate hypersensitivity skin test, saccharin test, flexible nasofibroscopy and nasal cytology. Study design: Crosssectional contemporary cohort. Results: Of the 33 people originally enrolled, 14 (42.4%) were excluded for clinical reasons. Of the 19 remaining, 2 (10.5%) had atopy diagnosed in the skin test and were excluded. 17 were tested with saccharin and presented normal mucociliary clearance. Evaluation by nasal endoscopy showed abnormality in 2 cases (11.8%) and these were excluded. The remaining 15 were submitted to nasal cytology, which proved normal, representing 45.5% of those initially included. Conclusion: The proposed protocol for sequential and excluding evaluation was effective in defining candidates for the establishment of control groups in clinical studies on nasal topical medications. © Revista Brasileira de Otorrinolaringologia. All Rights reserved.

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The velvetbean caterpillar Anticarsia gemmatalis Hübner attacks peanut leaves, and the use of resistant varieties has directly contributed to ecological and economic aspects of pest control. The aim of this work was to select resistant peanut genotypes to A. gemmatalis using cluster analyses (dendogram obtained by Ward's methods and K-means) and Principal Components analysis for data interpretation. The evaluated genotypes were: IAC 5, IAC 8112, IAC 22 and IAC Tatu ST with upright growth habit, and IAC 147, IAC 125, IAC Caiapó and IAC Runner 886 with runner growth habit, and soybean genotype BR 16 as a susceptible control. The biological parameters: leaf consumption, larval (4o instar) and pupal (24h old) weight, larval and pupal development time and adult longevity were evaluated at laboratory conditions. The genotypes IAC 147 and IAC Runner 886 were resistant to A. gemmatalis in both cluster tests, grouping apart from most of the other genotypes. Both dendrogram and K-means methods provided satisfactory biological explanation, and they can be complementary used together with Principal Component and vice-versa. These results suggest that cluster analyses may be an important statistical tool in the selection of host plant resistance.

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The aim of this study was to investigate the genetic variation, the genotype × soil interaction and the selection among and within Corymbia citriodora progenies in three different kinds of soils (Red Latossol, Quartz Sand and Purple Latossol), which occur in the Luiz Antônio Experimental Station, São Paulo State, Brazil. The progeny test was established 1983, using 56 open-pollinated families of C. citriodora. Twenty fve years after planting the following traits were measured: height, diameter at breast height (Dbh), stem form and survival. Best growth occurred in Purple Latossol. Significant differences among progenies were detected for most traits in all sites, suggesting the possibility of improvement by selection. In the analysis with sites, Significant differences among locals, progenies and genotypes × soil interaction were detected, confiming that the tested material has sufficient genetic variation to be explored by selection in all sites. The analysis of genotype × soil interaction indicates that growth traits present single interaction and the same progenies can be selected in each site. On the order hand, genotype × soil interaction for stem form and survival was complex; and specifc progenies need to be selected for each kind of soil. The population, due to its high genetic variation and strong genetic control of traits, permits to obtain considerable genetic gains by selection among and within progenies.