RESUMO
To throw light on the expression of ripening-related genes in prickly pear (Opuntia sp.) fruits and on the possible role of the gaseous hormone ethylene in nonclimacteric fruit ripening, cDNA fragments that showed high homologies with 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase cDNAs from other plants were cloned and partially characterized. Thus, the corresponding genes were accordingly named opaccs-1 and opacco-1, after Opuntia ACC synthase-1 and Opuntia ACC oxidase-1, respectively. Southern analysis suggests the presence of at least one copy of both genes, as well as other related homologous sequences in the Opuntia genome. Northern analysis of the opaccs-1 gene shows an enhanced expression in ripening fruit tissues, whereas opacco-1 expression is highly induced in ripe tissues with respect to the green fruits and mature cladodes. These results are in agreement with an active metabolic role of ethylene during nonclimacteric prickly pear fruit ripening. This is the first report on the analysis at the molecular level of ripening-related genes of the Opuntia genus.
Assuntos
Frutas/crescimento & desenvolvimento , Frutas/genética , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Opuntia , Aminoácido Oxirredutases/química , Aminoácido Oxirredutases/genética , Sequência de Aminoácidos , Sequência de Bases , DNA Complementar/química , DNA Complementar/genética , DNA Complementar/isolamento & purificação , DNA de Plantas/química , Frutas/metabolismo , Liases/química , Liases/genética , Dados de Sequência Molecular , Opuntia/genética , Opuntia/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de SequênciaRESUMO
Huitlacoche is the ethnic name applied to the young fruiting bodies (galls) of the fungus Ustilago maydis, which causes common smut of maize (Zea mays L). Biologists and agronomists have historically used U. maydis as a model to study a wide array of genetic, physiological, ecological, and phytopathological phenomena. In Mexico and other Latin American countries, huitlacoche has been used traditionally as human food, being highly regarded as an interesting dish or condiment. The food potential of huitlacoche is described here in terms of its chemical composition, which includes carbohydrates, proteins, fats, vitamins, and minerals. In addition, essential amino acids (especially lysine) and fatty acids (linoleate) are present in huitlacoche in considerable levels, adding to its nutritional attributes. The feasibility of growing U. maydis in submerged agitated culture has yielded a variety of fermentation products, including essential amino acids, proteins, vitamins, and flavorings, among others. Recent interest in developing huitlacoche as a cash crop has come from increasing acceptance by the North American public, who prize it as a new delicacy. However, research efforts are still needed to determine the biological factors involved in the establishment of U. maydis as a pathogen on the maize plant. This review deals with the role of huitlacoche as a food source, implicating the biological components that will determine the development of technologies for large scale production.
Assuntos
Alimentos , Ustilago , História do Século XX , Humanos , América Latina , México , Doenças das Plantas , Esporos Fúngicos , Ustilago/classificação , Ustilago/genética , Ustilago/fisiologia , Zea mays/microbiologiaRESUMO
Micro-Kjeldahl, Lowry and Bradford procedures were compared for determining the protein content of Phaseolus vulgaris seeds during their development. Micro-Kjeldahl and biuret techniques were also compared with mature seeds of a normal and a genetically-improved bean cultivar. The protein contents of casein and soy protein isolate were as well estimated by these four methods. For many samples of both bean and food protein products large disagreements were found between micro-Kjeldahl and the other three procedures.
