156 research outputs found

    Effect of Selected Volatiles on Two Stored Pests: The Fungus Fusarium verticillioides and the Maize Weevil Sithophilus zeamais

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    New agronomic practices and technology enabled Argentina a larger production of cereal grains, reaching a harvest yield of 26.5 million metric tons of maize, of which, about 40% was exported. However, much of the maize production is lost annually by the attack of fungi and insects (2.6 million tons). In this study, the antifungal effect of selected volatiles on Fusarium verticillioides, its mycotoxin production, and the repellent and insecticidal activities against the weevill Sithophilus zeamais, an insect vector of F. verticillioides, were evaluated. The compounds tested were (2E)-2-hexenal, (2E)-2-nonenal,(2E,6Z)-2,6-nonadienal, 1-pentanol, 1-hexanol, 1-butanol, 3-methyl-1-butanol, pentanal, 2-decanone, and 3-decanone, which occur in the blend of volatile compounds emitted by various cereal grains. The most active antifungals were the aldehydes (2E)-2-nonenal, (2E)-2-hexenal, and (2E,6Z)-2,6-nonadienal (minimum inhibitory concentration values of <0.03, 0.06, and 0.06 mM,respectively). The occurrence of fumonisin B1 also was prevented because these compounds completely inhibited fungal growth.The best insecticidal fumigant activities against the maize weevil were shown by 2-decanone and 3-decanone (lethal concentration ≤ 54.6 μL/L (<0.28 mM)). Although, all tested compounds showed repellent activity against S. zeamais at a concentration of 4 μL/L, (2E,6Z)-2,6-nonadienal was the most active repellent compound. These results demonstrate the potential of (2E,6Z)-2,6-nonadienal to be used as a natural alternative to synthetic pesticides on F. verticillioides and S. zeamais.Fil: Zunino, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Herrera, Jimena María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); ArgentinaFil: Pizzolitto, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Rubinstein, Héctor Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Bioquímica Clínica E Inmunología; Argentina; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Zygadlo, Julio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Dambolena, Jose Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba; Argentin

    Archaeological memory and urban morphology: the republican model in the imperial E42

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    The idea that the modern city should rise on a tabula rasa of the ancient city has been promoted since the Plan Voisin (Lecorbusier, 1925), and was essentially conceived on the ideology of the destruction of the ancienne regime, or to better say the destruction of its space, as a base to build a new world. Nowadays we recognize that demolitions of urban fabric inside historical cities are not conceivable, they were accomplished mostly by absolutist regimes or war bombings, upholding in substance the very same effect. Therefore we should reconsider critically the foundation of the E42 in Rome (1941), shown by fascist propaganda as a modern foundation, but planned outside the city centre. Even though meaningful demolitions were accomplished inside the monumental area of the Roman forums in the ‘30, in a very subtle manner, the archaeological topography of the ancient republican Rome became part of the new E42. The foundation was based on analogous orientations, in relationship with the foundation day of ancient Rome. Form and meaning of architectures, recalling the memory urban parts of ancient Rome, were used as archetypes to symbolize the past glory of Rome. This study presents the comparative analysis of the Palace of Receptions and Congresses (Adalberto Libera, 1938) and of the Temple of Venus and Rome (Hadrian, 121 ad), analyzing the city through models, proposing a new interpretation of the E42 as an analogous city. This comparative analysis recognizes in the plan elements of non-immediate perception, tracing a key to understand the meaning of the spaces of the city.Publisher versio

    Larvicidal effects of endophytic and basidiomycete fungus extracts on Aedes and Anopheles larvae (Diptera, Culicidae)

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    Introduction In vitro bioassays were performed to access the larvicidal activity of crude extracts from the endophytic fungus Pestalotiopsis virgulata (Melanconiales, Amphisphaeriaceae) and the saprophytic fungus Pycnoporus sanguineus (Basidiomycetes, Polyporaceae) against the mosquitoes Aedes aegypti and Anopheles nuneztovari. Methods The extracts were tested at concentrations of 100, 200, 300, 400 and 500ppm. Ethyl acetate mycelia (EAM) extracts and liquid culture media (LCM) from Pe. virgulata and Py. sanguineus were tested against third instar larvae of Ae. aegypti and An. nuneztovari. Results The larvicidal activity of the EAM extracts from Pe. virgulata against Ae. aegypti had an LC50=101.8ppm, and the extract from the basidiomycete fungus Py. sanguineus had an LC50=156.8ppm against the Ae. aegypti larvae. The Pe. virgulata extract had an LC50=16.3ppm against the An. nuneztovari larvae, and the Py. sanguineus extract had an LC50=87.2ppm against these larvae. Conclusions These results highlight the larvicidal effect of EAM extracts from the endophyte Pe. virgulata against the two larval mosquitoes tested. Thus, Pe. virgulata and Py. sanguineus have the potential for the production of bioactive substances against larvae of these two tropical disease vectors, with An. nuneztovari being more susceptible to these extracts
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