188 research outputs found
Melhoramento do cafeeiro: ênfase na aplicação dos marcadores moleculares.
O melhoramento genético de plantas constitui em metodologias para a criação, seleção e fixação de plantas contendo fenótipos superiores, visando o desenvolvimento de cultivares melhoradas para as necessidades dos agricultores e consumidores. Dessa forma, o melhoramento de plantas tem sido definido como ?a ciência e a arte de modificar as plantas em benefício da sociedade? ou ?a ciência, arte e o gerenciamento dos recursos visando o aperfeiçoamento das plantas para o benefício da sociedade?. Como arte, o melhoramento depende da intuição e das experiências passadas que são únicas para cada melhorista, e como ciência, depende dos princípios da agronomia, genética e outras ciências correlatas. No entanto, a tendência é aumentar a ?ciência? e depender menos da arte para tornar o processo cada vez mais eficiente. Dessa forma, o programa de melhoramento eficiente é aquele que, além da intuição do melhorista, se baseia no amplo conhecimento da cultura, biologia da planta, genética clássica, genética de populações, biometria e genética quantitativa, citogenética, genética molecular, fisiologia da planta e processo evolutivo da cultura
Caracterização molecular de mutantes de bananeira da cv. terra por meio de marcadores ISSR.
A técnica de indução de mutação por irradiação tem sido muito empregada em programas de melhoramento de plantas visando a seleção de mutantes com características agronômicas desejáveis. Os marcadores moleculares são importantes ferramentas para a detecção dos efeitos da radiação gama com precisão, uma vez que, com o advento das técnicas modernas de biologia molecular, surgiram diversos métodos de detecção de polimorfismo genético direto; ou seja, em nível de DNA. O maior interesse na aplicação dos marcadores genéticos no melhoramento vegetal é a perspectiva de estabelecer ligações entre os marcadores e os genes que controlam determinada característica (OLIVEIRA et al., 1996).pdf 159
Variabilidade genética de populações naturais de caroá por meio de marcadores RAPD.
O objetivo deste trabalho foi quantificar a variabilidade genética entre e dentro de populações de caroá (Neoglaziovia variegata), por meio de marcadores "" (RAPD). Foram analisados 180 genótipos de caroá, provenientes dos municípios de Guanambi, Juazeiro e Valente, no Estado da Bahia. Foi observado elevado polimorfismo entre as populações de caroá. As dissimilaridades genéticas entre os genótipos variaram de 0,08 a 0,95, com média de 0,44. A variância molecular mostrou que 56% da variação total foi explicada pelas diferenças entre indivíduos dentro de locais. As diferenças entre municípios explicaram 17% da variação total, enquanto as diferenças entre locais dentro dos municípios explicaram 26% da variação
Fingerprint molecular de híbridos e porta-enxertos (PEs) de citros via marcadores moleculares ISSRs e SSR.
O Brasil é o primeiro produtor mundial de citros e o maior exportador de suco de laranja doce, principal produto do complexo agroindustrial da citricultura brasileira. De expressiva importância socioeconômica, a citricultura é responsável por integrar o país na liderança internacional
Caracterização agronômica e molecular de mutantes de bananeira 'Pacovan'.
A indução de mutação por raios gama, juntamente com as técnicas de cultivo in vitro, constitui uma ferramenta para os programas de melhoramento visando à redução do porte em bananeira. Essa técnica de mutação induzida tem como objetivo promover o melhoramento de uma única característica governada por um ou poucos genes, conservando as outras características do fenótipo original. Os ISSRs (Inter Simple Sequence Repeats) são marcadores dominantes e reproduzíveis, com a vantagem de gerar grandes quantidades de bandas, sendo amplamente distribuídos ao longo do genoma de eucariontes (FANG & ROOSE, 1997). O objetivo deste trabalho foi selecionar mutantes putativos com porte reduzido da cultivar Pacovan submetida a irradiação com raios gama e estimar a variabilidade genética mediante a utilização de marcadores moleculares ISSR.pdf 159
Artificial neural networks compared with Bayesian generalized linear regression for leaf rust resistance prediction in Arabica coffee.
The objective of this work was to evaluate the use of artificial neural networks in comparison with Bayesian generalized linear regression to predict leaf rust resistance in Arabica coffee (Coffea arabica). This study used 245 individuals of a F2 population derived from the self-fertilization of the F1 H511-1 hybrid, resulting from a crossing between the susceptible cultivar Catuaí Amarelo IAC 64 (UFV 2148-57) and the resistant parent Híbrido de Timor (UFV 443-03). The 245 individuals were genotyped with 137 markers. Artificial neural networks and Bayesian generalized linear regression analyses were performed. The artificial neural networks were able to identify four important markers belonging to linkage groups that have been recently mapped, while the Bayesian generalized model identified only two markers belonging to these groups. Lower prediction error rates (1.60%) were observed for predicting leaf rust resistance in Arabica coffee when artificial neural networks were used instead of Bayesian generalized linear regression (2.4%). The results showed that artificial neural networks are a promising approach for predicting leaf rust resistance in Arabica coffee.Título em português: Redes neurais artificiais comparadas com modelos lineares generalizados sob o enfoque bayesiano para predição de resistência à ferrugem em café arábica
Developing resources to facilitate culturally-sensitive service planning and delivery – doing research inclusively with people with learning disabilities
Background Black, Asian and minority ethnic people with learning disabilities face inequities in health and social care provision. Lower levels of service uptake and satisfaction with services have been reported, however, this is largely based on the views of carers. The ‘Access to Social Care: Learning Disabilities (ASC-LD)’ study sought to explore the views and experiences of social support services among adults with learning disabilities from Black, Asian and minority ethnic communities. Interviews with 32 Black, Asian and minority ethnic adults with learning disabilities were conducted to explore participants’ cultural identities, their understanding and experience of ‘support’. The views and experiences expressed in the ASC-LD study were used in the ‘Tools for Talking project’ to develop a suite of resources designed to facilitate culturally-sensitive communication and information-sharing, service planning and delivery through improved mutual understanding between providers and users of services. This paper describes the Tools for Talking project which sought to co-develop the resources through a partnership event. Methods An inclusive approach was adopted to address issues that are important to people with learning disabilities, to represent their views and experiences, and to involve Black, Asian and minority ethnic people with learning disabilities in the research process. Partnerships were developed with provider organisations and service users who were invited to a ‘Partnership Event’. Collaborators at the partnership event were asked to comment on and evaluate draft resources which included a series of videos and activities to explore topics that emerged as important in the ASC-LD study. Their comments were collated and the tools developed as they suggested. Results Using the results from the ASC-LD study helped to ensure that the draft resources were relevant to service users, addressing topics that were important to them. The partnership event was an effective method to collaborate with a relatively large number of stakeholders. However, the event was resource intensive and required substantial planning to ensure active and meaningful participation. Considerations, such as inviting stakeholders, developing the programme and selecting a venue are discussed. Conclusions The partnership approach has led to the development of a set of five illustrative videos and accompanying activities that address issues that emerged from the collaborative process including: culture, activities, support from staff, important people, choices and independence. These resources are freely available at: www.Toolsfortalking.co.uk. They are designed to be used by users and providers of services, but may also be useful in other settings
Identificação e análise da expressão de genes relacionados com o mal-do-Panamá em bananeira, por meio de PCR em Tempo Real.
A banana é a fruta mais consumida no mundo. No Brasil é cultivada em todo país, destacando-se como cultura de maior expressão econômica. Dentre as doenças que ocorrem o 'mal-do-Panamá', causado pelo fungo Fusarium oxysporum f.sp. cubense (Foc), altamente destrutivo limitando a produção
Protein N-terminal acetylation: NAT 2007–2008 Symposia
Protein N-terminal acetylation is a very common modification, but has during the past decades received relatively little attention. In order to put this neglected field back on the scientific map, we have in May 2007 and September 2008 arranged two international NAT symposia in Bergen, Norway. This supplement contains selected proceedings from these symposia reflecting the current status of the field, including an overview of protein N-terminal acetylation in yeast and humans, a novel nomenclature system for the N-terminal acetyltransferases (NATs) and methods for studying protein N-terminal acetylation in vitro and in vivo
A Grassmann integral equation
The present study introduces and investigates a new type of equation which is
called Grassmann integral equation in analogy to integral equations studied in
real analysis. A Grassmann integral equation is an equation which involves
Grassmann integrations and which is to be obeyed by an unknown function over a
(finite-dimensional) Grassmann algebra G_m. A particular type of Grassmann
integral equations is explicitly studied for certain low-dimensional Grassmann
algebras. The choice of the equation under investigation is motivated by the
effective action formalism of (lattice) quantum field theory. In a very general
setting, for the Grassmann algebras G_2n, n = 2,3,4, the finite-dimensional
analogues of the generating functionals of the Green functions are worked out
explicitly by solving a coupled system of nonlinear matrix equations. Finally,
by imposing the condition G[{\bar\Psi},{\Psi}] = G_0[{\lambda\bar\Psi},
{\lambda\Psi}] + const., 0<\lambda\in R (\bar\Psi_k, \Psi_k, k=1,...,n, are the
generators of the Grassmann algebra G_2n), between the finite-dimensional
analogues G_0 and G of the (``classical'') action and effective action
functionals, respectively, a special Grassmann integral equation is being
established and solved which also is equivalent to a coupled system of
nonlinear matrix equations. If \lambda \not= 1, solutions to this Grassmann
integral equation exist for n=2 (and consequently, also for any even value of
n, specifically, for n=4) but not for n=3. If \lambda=1, the considered
Grassmann integral equation has always a solution which corresponds to a
Gaussian integral, but remarkably in the case n=4 a further solution is found
which corresponds to a non-Gaussian integral. The investigation sheds light on
the structures to be met for Grassmann algebras G_2n with arbitrarily chosen n.Comment: 58 pages LaTeX (v2: mainly, minor updates and corrections to the
reference section; v3: references [4], [17]-[21], [39], [46], [49]-[54],
[61], [64], [139] added
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