Isolamento e avaliação da atividade nematicida de constituintes químicos de Mucuna cinerea contra Meloidogyne incognita e Heterodera glycines

Phytochemical investigation of the aerial parts and roots of Mucuna cinerea led to the isolation of a mixture of fatty acids, triacylglicerols, beta-sitosterol, stigmasterol, stigmasterol glucoside, daucosterol, asperglaucide (4) and the isoflavonoids prunetin (1), genistein (2), medicarpin (3), daidzein (5), 7-O-alpha-glycopiranosyl daidzein (6). An in vitro bioassay was carried out with compounds 1-4, at the concentration of 50 and 5 mug mL-1 against the phytonematodes M. incognita and H. glycines. Although the four compounds showed some nematocidal property, the most active was (1), causing 70% mortality of M. incognita at the concentration of 50 mug mL-1.

Planejamento fatorial aplicado à digestão de amostras de feijão assistida por radiação microondas

The use of factorial design was evaluated for optimization of focused-microwave-assisted digestion of bean samples. Calcium, Fe, Mg, Mn and Zn percentual recoveries were determined in digestates after focused-microwave-assisted digestion according to factorial design procedures. A cavity microwave digestion was carried out to certify the elemental compositions obtained. The accuracy was checked using a standard reference material, the NIST SRM 8433 - Corn Bran. Results are in agreement with certified values at the 95% confidence limit when the Student t-test was used. Volumes of nitric and sulfuric acid, temperature, and the interplay between HNO3 and H2SO4 initial volumes were significant variables according to P-values in the analysis of variance (ANOVA).

Produção de matéria seca e de grãos por plantas de feijoeiro (Phaseolus vulgaris L.) cultivadas em solos tratados com metais pesados

This work aimed at evaluating the contents of extractable Cd, Pb, Zn and Cu with a solution of DTPA (diethyleneaminopentacetic acid) and to relate them with the production of dry material and grain production of bean plants under two conditions of experimentally contaminated soil materials with Cd, Pb, Cu and Zn: (i) samples of distrofic red latosol and (ii) humic yellow-red latosol. A decrease in the yield of dry matter was observed for all treatments, if compared with the zero-dose control sample; the grain yield was affected for the soil samples treated with Cd and Cu but only slightly for those treated with Pb and Zn.

Produção de etanol a partir de torta de mamona (Ricinus communis L.) e avaliação da letalidade da torta hidrolisada para camundongos

The castor bean cake is rich in starch (48 ± 0.53%) and bears a problem linked to the occurrence of a toxic protein (ricin). The chemical hydrolysis (ratio solid:liquid = 1:6; H2SO4= 0.1 mol L-1; 120 °C; 40 min) generated a medium with 27 g L-1 of reducing sugars (hydrolysis efficiency= 32%). The hydrolyzed product was fermented and produced 11 g L-1 of ethanol (volumetric productivity=1.38 g L-1 h-1 and ethanol yield on substrate consumed=0.45 g g-1). In vivo experiments (DL50) revealed a reduction of roughly 240 times in the CBC toxicity (2.11 µg g-1).

Biodiesel: visão crítica do status atual e perspectivas na academia e na indústria

This article presents a bibliographic review of research carried out on different alternative processes for biodiesel production. The supercritical and subcritical (non catalytic) reaction conditions, the use of solid basic, solid acid and other heterogeneous catalysts, including the use of immobilized enzymes and whole-cell catalysts are also critically compared with the traditional homogeneous alkaline or acid catalysts that are common on industrial applications. Advantages and limitations of all these processes for the transference from the laboratory to the industry are discussed. A correlation of the chemical composition with the quality parameters of the produced biodiesel is done with aim to stablish adequate procedures for the right selection of the raw-material. Castor bean oil is used as an example of inappropriate oil in order to produce a B100 that fulfill all the international physico-chemical quality standards. In this article are presented research results to adequate the values of viscosity, density and iodine number of the castor and soybean biodiesel to the international standard limits by means blending these both biodiesels at the right ratio.

Produção e caracterização de carvão ativado produzido a partir do defeito preto, verde, ardido (PVA) do café

The black, green and sour coffee defect (PVA) contributes with 20% of the total coffee production. It should be separate from the normal coffee grains in order to improve the final quality of the beverage. In this way, the present work has the objective to use the PVA reject for the production of activated carbon. The activated carbon (CA) was prepared from PVA defect using zinc chloride as activating agent. The prepared material (CA PVA) was characterized and the adsorption tests were carried out using as organic models methylene blue (AM) and reactive red (VR). The CA PVA revealed to be more efficient in the removal of the organic contaminants compared to a commercial activated carbon.

Nutrientes (K, P, Ca, Na, Mg e Fe) em sedimentos (solos aluviais) e cultivares (feijão e milho) de praias e barrancos de rios de água branca: a bacia do purus no estado do Acre, Brasil

The present research highlights the macronutrient abundance in the sediments of beaches and cliffs and cultivates in the river Purus and flowing, southwest of Amazon. The concentrations found in leaves and bean seeds and corn leaves reflect the mineralogical and chemical nature of those rich sediments in K2O and Na2O, which are formed by smectite, illite and K-feldspar. The factors of transfer of the elements in the corn leaves and bean (Ca>K>Na) and bean seeds (Na>K>Ca) demonstrate that the nutrient needs of the cultivate were found appropriately in the sediments (soils) of the beaches and cliffs.

Preparação, caracterização e propriedades de filmes poliméricos com potencial aplicação no recobrimento de sementes

Films of sodium carboxymethyl cellulose, sodium alginate and their mixture were evaluated in terms of interactions between the polymers, morphology, water absorption and application as seed coatings. FTIR analysis suggested that only hydrophobic interactions occurred between the polymers. The coating of bean seeds was confirmed by microscopy, indicating the formation of dense and homogeneous films with 7 μm thickness. The obtained films did not affect the germination capacity of the seeds. In summary, the characteristics and properties of the films formed and the water absorption capacity, indicate that these systems are viable for use in seed coating processes.

Produção de concentrados de ácidos graxos por hidrólise de óleos vegetais mediada por lipase vegetal

The aim of this work was to verify the ability of enzymatic crude extract from dormant castor bean seeds to yield concentrated fatty acids by hydrolysis of polyunsaturated vegetable oils such as corn and sunflower. The enzymatic extract exhibited higher activity towards corn oil, which was selected for further studies to determine optimum hydrolysis conditions by factorial design. Maximum hydrolysis percentage (≈84%) was reached at 60% wt. oil:buffer acetate 100 mM pH 4.5, 33 ºC and 5.0% wt. of crude extract after 70 min of reaction. These results suggest that the use of low-cost lipase from castor bean seeds has potential for oil hydrolysis.

NANOPARTÍCULAS DE PROTEÍNA ISOLADA DE SOJA EM ÁGUA: EFEITO DA FORÇA IÔNICA E DAS CONCENTRAÇÕES DE PROTEÍNA E SURFACTANTE

Soft nanoparticles of size 200-400 nm were obtained from soybean protein isolate (SPI). The particles were formed and suspended in water by the coacervation of aqueous suspensions of SPI in hostile buffered aqueous solutions in the presence of surfactants. We investigate the effect of storage, ionic strength, and concentrations of SPI and surfactant on nanoparticle size and zeta potential. Transmission electron microscopy images and scattering techniques (SLS/ DLS) revealed that the particles are spherical, with hydrophilic chains at the surface.

Distribuição de geminivírus nas culturas do tomate e pimentão em doze municípios do Submédio do Vale São Francisco

Em 1996 e 1997, observaram-se sintomas de viroses causadas por geminivírus transmitidos por mosca branca em plantas de tomateiro (Lycopersicon esculentum) e pimentão (Capsicum annuum) no Submédio do Vale São Francisco, situado nos Estados de Pernambuco e Bahia. De outubro de 1996 a dezembro de 1998, foram coletadas 1.368 amostras foliares de tomateiro e 194 de pimentão, exibindo sintomas similares àqueles causados por geminivírus, em 104 e 16 plantios, respectivamente, de 12 municípios dessa região e em dois municípios vizinhos. A incidência de geminiviroses nas áreas amostradas foi estimada entre 5 e100% para tomate e entre 10 e 20% para pimentão. A detecção de geminivírus nas amostras foi feita por "dot blot" ou "squash blot" utilizando-se sondas heterólogas. Para as amostras de tomate, a sonda foi constituída pelos componentes A completos de dois isolados, um de Bean golden mosaic virus (BGMV) do Brasil e outro de Bean golden yellow mosaic virus (BGYMV) da Guatemala, enquanto que para pimentão, esta foi constituída apenas por um fragmento do componente A de um isolado de geminivírus de tomate do Distrito Federal. Do total de 1562 amostras analisadas, em 908 (58,1%) confirmou-se a presença de geminivírus, sendo 823 (60,2%) de tomate e 85 (43,8%) de pimentão. A presença de plantas infetadas foi detectada em todos os 120 plantios, com incidência entre 20 e 100%, indicando ampla disseminação de geminivírus nestas culturas no Submédio do Vale São Francisco.

Identification of Phaeoisariopsis griseola pathotypes from five States in Brazil

Due to the increased importance of angular leaf spot of common bean (Phaseolus vulgaris) in Brazil, monitoring the pathogenic variability of its causal agent (Phaeoisariopsis griseola) is the best strategy for a breeding program aimed at developing resistant genotypes. Fifty one isolates of P. griseola collected in five Brazilian States were tested on a set of 12 international differential cultivars in the greenhouse. When inoculated plants showed symptoms but no sporulation was observed, they were transferred to a moist chamber for approximately 20-24 h. After this period of time, if no sporulation was observed, the plants were considered resistant; otherwise, they were considered susceptible. From the fifty-one tested isolates, seven different pathotypes were identified. No Andean pathotypes were identified; consequently, all isolates were classified as Middle American pathotypes. Pathotype 63-31 was the most widespread. Pathotype 63-63 overcame resistance genes present in all differential cultivars and also the resistance gene(s) present in the cultivar AND 277. This fact has important implications for breeding angular leaf spot resistance in beans, and suggests that searching for new resistance genes to angular leaf spot must be pursued.

Uptake and translocation of nitrogen, phosphorus and calcium in soybean infected with Meloidogyne incognita and M. javanica

Two soybean (Glycine max) cultivars were used in this study, Ocepar 4, rated as moderately resistant to Meloidogyne incognita race 3 but susceptible to M. javanica, and 'BR 16', susceptible to both nematodes. The effect of nematodes infection on the uptake and transport of N, P and Ca to the shoot was studied in plants growing in a split root system. The upper half was inoculated with 0, 3,000, 9,000 or 27,000 eggs/plant while the lower half received 15N, 32P or 45Ca. Infected plants showed an increase of root but a decrease of shoot mass with increasing inoculum levels. In general, total endogenous nutrients increased in the roots and tended to decrease in the shoots with increasing inoculum levels. When concentrations were calculated, there was an increase in the three nutrients in the roots, and an increase of Ca but no significant variation of N and P was observed in the shoots. The total amount of 15N in the roots increased at the highest inoculum levels but 32P and 45Ca decreased. In the shoots there was a reduction of 32P and 45Ca. The specific concentrations of the labelled nutrients (abundance or radioactivity/tissue mass) also showed a decrease of 32P and 45Ca in the shoots and roots of infected plants and an increase of 15N in the shoots. Considering that overall nutrient concentrations reflect cumulative nutrient uptake and the data from labelled elements gave information at a specific moment of the infection, thus nematodes do interfere with nutrient uptake and translocation.

Telomere and microsatellite primers reveal diversity among Sclerotinia sclerotiorum isolates from Brazil

Sclerotinia sclerotiorum, the causal agent of white mold, is a problem of winter bean (Phaseolus vulgaris) production in Brazil under center-pivot irrigation. Isolates of S. sclerotiorum were obtained from a center-pivot-irrigated field near Guaíra-SP, Brazil. Mycelial compatibility group (MCG) studies revealed the presence of only two MCG. PCR/RFLP analysis of the ITS1-5.8S-ITS2 ribosomal subunit regions of these field isolates of S. sclerotiorum failed to show any genetic differences between these two MCGs. DNA amplification with a chromosomal telomere sequence-based primer and one microsatellite primer revealed genetic polymorphisms among isolates within the same MCG. Isolates taken from beans and two other crops from another region of Brazil showed the same two MCG and had identical banding patterns for the telomere and microsatellite primers. These findings support the use of telomere sequence-based primers for revealing genotypic differences among S. sclerotiorum isolates.

Análise molecular de segmento do RNA2 de comovirus isolados de soja no estado do Paraná

Nas áreas produtoras de feijão (Phaseolus vulgaris) do Estado do Paraná observa-se anualmente a ocorrência do vírus do mosaico em desenho do feijoeiro (Bean rugose mosaic virus, BRMV), principalmente em infecções mistas com o vírus do mosaico dourado do feijoeiro (Bean golden mosaic virus, BGMV), acarretando maior severidade de sintomas e causando perdas na produção. Recentemente constatou-se a presença do vírus do mosaico severo do caupi (Cowpea severe mosaic virus, CPSMV) associado a sintomas de queima do broto em plantações de soja (Glycine max) na região de Londrina, sendo este um fato novo no Estado. Neste trabalho, parte do RNA2 de dois comovirus isolados de soja no Paraná foram clonados e sequenciados, sendo 600 pares de bases (pb) do BRMV-PR e 594 pb do CPSMV-PR. Posteriormente, as seqüências correspondentes de aminoácidos foram comparadas com seis seqüências de vírus do gênero Comovirus depositadas no GenBank. Com base nestes dados observou-se que o segmento do RNA2 do isolado CPSMV-PR apresentou homologia de 85% com parte de uma seqüência já conhecida do RNA2 do CPSMV, enquanto que o segmento do RNA2 do isolado BRMV-PR apresentou homologia de 39% com o CPSMV, e de 44% com o Bean pod mottle virus (BPMV). Este trabalho apresenta pela primeira vez dados de sequenciamento parcial do BRMV, o que poderá contribuir para sua completa caracterização molecular e para o estabelecimento de estratégias para obtenção de plantas resistentes ao vírus.