Seleção de bactérias endofíticas com potencial para controle biológico in vitro de Fusarium oxysporum f. sp. cubense.

Controle biológico é o uso de organismos através de uma ação direta sobre outro antagônico, podendo este atuar por meio de antibiose, parasitismo, competição, predação, ou hipovirulência. O controle biológico tem sido utilizado em diferentes campos da biologia, principalmente na entomologia e fitopatologia, contribuindo em uma primeira fase na transição agroecológica para a redução do uso de agroquímicos. O mal-do-Panamá é uma doença endêmica por todas as regiões produtoras de banana do mundo, causada pelo fungo Fusarium oxysporum f. sp. cubense (E.F. Smith) Sn e Hansen., que apresenta alta capacidade de sobrevivência mesmo na ausência do hospedeiro. Uma forma de controle de F. oxiporum f. sp. cubense pode ser o uso de bactérias endofíticas com intuito controlar e inibir o desenvolvimento do mesmo. Deste modo o presente teve como objetivo selecionar bactérias endofíticas de bananeira para uso no controle biológico in vitro de F. oxysporum f. sp. cubense. Foram analisados 148 isolados obtidos de cultivares de bananeiras Pisang, FHIA18, BRS conquista, e Pacovan. O teste de antagonista in vitro entre F. oxysporum f. sp. cubense e bactétias endofíticas foi realizado em meio TSB. Fragmentos de micélio foram incubados à 28ºC (fotoperíodo de 12 horas) e após 3 dias crescimento as batectérias endofíticos foram inoculados e incubados à 28ºC (fotoperíodo de 12 horas) durante 4 dias. Das 148 bactérias avaliadas, nenhuma apresentou halo de inibição, contudo 18 apresentaram atividade antagônica contra F. oxysporum f. sp. cubense por competição. Os dados obtidos indicam que o agente de biocontrole apresenta boa capacidade de competição por espaço e nutrientes. Bactérias isoladas de bananeiras dos diferentes cultivares, apresentaram o mesmo potencial para controle de F. oxysporum f. sp. cubense, in vitro

Nitrogen oxides measurements in an Amazon site and enhancements associated with a cold front

International audienceAn intensive atmospheric chemistry study was carried out in a pristine Amazonian forest site (Balbina), Amazonas state, Brazil during the 2001 wet season, as part of the LBA/CLAIRE 2001 (The Large Scale Biosphere Atmosphere Experiment in Amazonia/Cooperative LBA Airborne Regional Experiment) field campaign. Measurements of nitrogen oxide (NO), nitrogen dioxide (NO2) and ozone (O3) were performed simultaneously with aerosol particles and black carbon concentrations and meteorological parameters observations. Very low trace gases and aerosol concentrations are typically observed at this pristine tropical site. During the measurement period, there was a three-day episode of enhancement of NO2 and black carbon concentration. NO2 concentration reached a maximum value of 4 ppbv, which corresponds to three times the background concentration observed for this site. Black carbon concentration increased from the approximated 100 ng/m3 average value to a 200 ng/m3 maximum during the same period. Biomass burning spots were detected southward, between latitudes 15 to 10° S, 5?6 days before this episode from GOES-8 WF_ABBA (Wildfire Automated Biomass Burning Algorithm). An atmospheric numerical simulation of the whole measurement period was carried out using the RAMS model coupled to a biomass burning emission and transport model. The simulation results pictured a smoke transport event from Central Brazil associated to an approach of a mid-latitude cold front, reinforcing the hypothesis of biomass burning products being long-range transported from the South by the cold front and crossing the Equator. This transport event shows how the pristine atmosphere pattern in Amazonia is impacted by biomass burning emissions from sites very far away

Coleção espécies arbóreas da Amazônia: glossário de termos botânicos.

bitstream/item/223529/1/Colecao-especies-arboreas.pdfVolume especial

Isolation and identification of pigment-producing endophytic fungi from the Amazonian species Fridericia chica.

Pigments of fungal origin have aroused increasing interest in the food dye and cosmetic industries since the global demand for natural dyes has grown. Endophytic microorganisms are a source of bioactive compounds, and Amazonian plant species can harbor fungi with a wide range of biotechnological applications. Popularly known in Brazil as crajiru, Fridericia chica is a medicinal plant that produces a red pigment. In this study, a total of 121 fungi were isolated in potato dextrose agar from three plants. We identified nine pigment-producing endophytic fungi isolated from branches and leaves of F. chica. The isolates that showed pigment production in solid media were molecularly identified via multilocus analysis as Aspergillus welwitschiae, A. sydowii, Curvularia sp., Diaporthe cerradensis (two strains), Hypoxylon investiens, Neoscytalidium sp. (two strains) and Penicillium rubens. These isolates were subjected to submerged fermentation in two culture media to obtain metabolic extracts. The extracts obtained were analyzed in terms of their absorbance between 400 and 700 nm. The pigmented extract produced by H. investiens in medium containing yeast extract showed maximum absorbance in the red absorption range (UA700 = 0.550) and significant antioxidant and antimicrobial activity. This isolate can thus be considered a new source of extracellular pigment

Leishmanicidal activity of the venoms of the Scorpions Brotheas amazonicus and Tityus metuendus

Abstract Leishmaniasis is a vector-transmitted zoonosis caused by different species of the genus Leishmania, with a wide clinical spectrum. It is a public health problem aggravated by a series of limitations regarding treatment. In the search for new therapeutic alternatives, scorpion venoms are a source of multifunctional molecules that act against the natural resistance of pathogens. This work evaluated the antileishmanial potential of Brotheas amazonicus and Tityus metuendus venoms against the promastigote forms of Leishmania amazonensis e Leishmania guyanensis. The venoms of B. amazonicus and T. metuendus were evaluated for their constituents using Fourier Transform Infrared (FTIR). Growth inhibition and death of promastigotes were evaluated in the presence of diferente crude venom concentrations (100 µg/mL, 50 µg/mL, 10 µg/mL, 1 µg/mL) after one hour of incubation at 25 °C. The FTIR spectra of both venoms exhibited bands in approximate regions, revealing that both exhibit similar functional groups. Crude venom from both scorpion species showed similar or superior leishmanicidal effects to the standart drug N-methylglucamine antimoniate. At the highest concentration of 100 µg/mL, cultures of L. guyanensis treated with the venom of B. amazonicus showed the highest mortality percentages, above 28%, while T. metuendus venom showed the highest activity against L. amazonensis, with mortality above 7%. This preliminar study demonstrates that B. amazonicus and T. metuendus venoms can be important tools in the search for new drugs Against leishmaniasis. Next step involves evaluating the activity against the amastigote forms and purifying the venom proteins in order to identify the best anti-leishmania candidates

Desempenho de plantas de cobertura em sobressemeadura na cultura da soja.

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Atividade antiparasitária de Streptomyces spp. frente a Trypanosoma cruzi.

Os medicamentos disponíveis para as tripanossomíases são poucos e apresentam toxicidade, e o surgimento de parasitas resistentes tem dificultado o tratamento, os Streptomyces tem sido nas últimas décadas uma fonte valiosa para desenvolver medicamentos eficazes contra várias doenças. Neste trabalho observamos que Streptomyces isolados dos Rios Madeira e Purus, foram capazes de inibir o crescimento de Trypanosoma cruzi in vitro e a análise foi realizada considerando-se a redução do desenvolvimento da infecção estabelecida, promovida pelo composto testado, em relação ao cultivo de células infectadas pelo parasito na ausência de extratos