Caracterização da diversidade genética em feijão por meio de marcadores RAPD

RAPD (Random Amplified Polymorphic DNA) markers were used to evaluate the genetic diversity among 19 common bean (Phaseolus vulgaris L.) cultivars. Amplifications using 15 decamers primers revealed 108 RAPD loci, 70 of which were polymorphic. The relative genetic distance was estimated using the complement of Jaccard’s coefficient and grouping analyses were derived from UPGMA and Tocher. These two grouping analyses confirmed the broad genetic diversity among the common bean tropical germplasm, which was divided into two main groups. These groups correspond to the Andean (genotypes with medium and large size seeds) and Mesoamerican (genotypes with small seeds) domestication centers. The relative genetic diversity was greater among the Andean cultivars than that of the Mesoamerican cultivars.Marcadores RAPD (Random Amplified Polymorphic DNA) foram usados para avaliar a diversidade genética entre 19 cultivares de feijão (Phaseolus vulgaris L.). Dos cento e oito locos de RAPD obtidos de 15 primers decâmeros, 70 foram polimórficos. Para estimar a distância genética foi usado o coeficiente de similaridade de Jaccard e as análises de agrupamento foram feitas pelos métodos UPGMA e Tocher. As análises de agrupamento confirmaram a ampla diversidade genética existente entre germoplasmas tropicais de feijão, separando as cultivares em dois grupos principais, correspondendo aos centros de domesticação Andino (genótipos de sementes médias e grandes) e Mesoamericano (genótipos de sementes pequenas). No grupo Andino, a diversidade genética relativa foi maior do que no Mesoamericano

Foliar analyses of biochemical parameters of Licania tomentosa (Benth.) and Bauhinia forficata (Link.) species for air quality assessment

Foliar analysis of biochemical parameters were carried out in order to investigate the influence of air pollutants on two tropical tree species (Licania tomentosa (Benth.) and Bauhinia forfícata (Link.)). Special attention was given to tropospheric ozone due to the fact that concentration levels in the region were found to be up to 140 µg m-3 for a 4 h average time, which is well above the value that can cause injuries to orchides and tobacco (59 µg m-3). Other pollutants such as nitrogen and sulphur oxides were measured and their ambient concentrations were also associated to biochemical alterations in the investigated species

Lipase-producing fungi for potential wastewater treatment and bioenergy production

The use of fungal biomass as a lipase biocatalyst represents an attractive approach for the treatments of oil wastewater as well as for the production of biodiesel from oil and residual grease, due to its greater  stability, possibility of reuse, and lower cost. In this work, 20 filamentous fungi were isolated from the grease trap scum of a restaurant at the Federal University of Espírito Santo, Brazil. The fungi included those belonging to the genera Aspergillus, Beauveria, Botrytis, Cladosporium, Colletotrichum, Fusarium, Geotrichum, Penicillium, Rhizomucor, and Verticillium. Fungal lipase activity and biomass production were quantified. Lipase activity ranged from 0.13 U mg-1 protein of Rhizomucor sp. ECGF18 to 18.06 U mg-1 protein of Penicillium sp. ECGF02, and the biomass production ranged from 7.61 mg mL-1 for  Cladosporium sp. ECGF19 to 12.68 mg mL-1 for Rhizomucor sp. ECGF18. In the sequence, Penicillium sp. ECGF02 and Rhizomucor sp. ECGF18, were previously select and, further evaluated in solid-state fermentation. Results confirmed the high extracellular lipase-activity of Penicillium sp.ECG02 and the high intracellular lipase activity of Rhizomucor sp. ECG18. Rhizomucor sp. ECG18 showed potential for use in future research, in the form of whole-cell lipases, wastewater treatment, and as a biocatalyst in the production of biodiesel from oil residues.Key words: Lipase-producing fungi, wastewater treatment, bioenergy

Efeito de extratos de própolis verde sobre bactérias patogênicas isoladas do leite de vacas com mastite

Erro no DOI, por isso foi disponibilizado o link de acesso.A sensibilidade, in vitro, de amostras de Staphylococcus aureus, Staphylococcus sp. coagulase negativos, Streptococcus agalactiae e bactérias do grupo dos coliformes, isoladas do leite de vacas com mastite, a diferentes extratos de própolis, na concentração de 100 mg/ml, foi avaliada pela técnica do antibiograma em discos de papel de filtro com sobrecamada de meio de cultura. Os resultados mostraram que o extrato etanólico de própolis comercial, os extratos etanólico e, em menor proporção, o metanólico inibiram o crescimento das amostras de bactérias Gram-positivas, Staphylococcus aureus, Staphylococcus sp. coagulase negativos e Streptococcus agalactiae. Os extratos obtidos através da água, do acetato de etila e do clorofórmio não inibiram nenhuma amostra bacteriana, assim como os veículos etanol e metanol puros utilizados como controle. A bactéria Gram-negativa testada, do tipo coliforme, não apresentou sensibilidade a nenhum dos extratos. Verificaram-se diferenças significativas (p < 0,05) na sensibilidade aos extratos entre amostras bacterianas de uma mesma espécie, mas de origens diferentes. Nas amostras de Streptococcus agalactiae, os diâmetros dos halos de inibição do crescimento bacteriano ao redor do disco foram maiores que aqueles observados para as amostras de Staphylococcus aureus e Staphylococcus sp. coagulase negativos. Todos estes resultados estimulam o prosseguimento de novas pesquisas sobre a utilização de extratos de própolis, em veículos adequados, com vistas ao tratamento da mastite bovina.In vitro, the sensitivity to different propolis extracts, at a concentration of 100 mg/ml, of Staphylococcus aureus, Staphylococcus sp. coagulase negative, Streptococcus agalactiae and bacteria of the coliform group, isolated from the milk of cows with mastitis, was evaluated using the technique of an agar disk diffusion with a medium doublelayer. The results showed that the commercial propolis, the ethanolic extract, and, in a minor proportion, the methanolic extract inhibited the growth of the Gram positive bacteria, Staphylococcus aureus, Staphylococcus sp. coagulase negative and Streptococcus agalactiae. The extracts obtained through water, etila acetate and chloroform did not inhibit any bacterial strains, nor did the pure ethanol and methanol vehicles that were utilized as controls. The Gram negative bacterium tested, from the coliform group, did not show sensitivity to any extract. Bacterial strains of the same species collected from different sources presented significant differences in sensitivity to the extracts (p < 0.05). In the Streptococcus agalactiae samples, the diameters of the zone of inhibition around the disks were bigger than those observed for samples of Staphylococcus aureus and Staphylococcus sp. coagulase negative. The results of this experiment stimulate the continuation of studies on the use of propolis extracts, by means of using the appropriate vehicles for the treatment of bovine mastitis

Not available

Trinta e seis estirpes de Rhizobium phaseoli foram estudadas quanto às suas características culturais, eficiência de fixação de nitrogênio, nível de resistência a drogas antimicrobianas, produção de bacteriocinas e capacidade competitiva entre determinadas estirpes. A maioria das estirpes de R. phaseoli caracterizaram-se como produtoras de ácido e crescimento rápido (3-5 dias) em cultura pura. A eficiência de fixação de nitrogênio variou de estirpe para estirpe, verificando-se em algumas delas, uma eficiência relativa em torno de 50%. Os níveis de resistência natural das estirpes, frente a sete drogas antimicrobianas, variaram, em µg/ml, de 1 a 10 para Estreptomicina, 1 a 20 para Espectinomicina, 1 a 50 para Cloranfenicol, 1 a 50 para Penicilina, 1 a 10 para Rifampicina, 0,01 a 0,1 para Tetraciclina e de 1 a 5 para Bicloreto de Mercúrio. Com base nas frequências destes níveis na população ensaiada, constatou-se em praticamente todos os casos, uma distribuição unimodal que a caracteriza como uma população sensível a tais drogas. Detectou- se a produção de bacteriocinas em 25% das estirpes analisadas, sendo que o antagonismo observado é altamente específico e a atividade bacteriocinogênica se mantém estável após passagem pela planta hospedeira. Os ensaios de competição entre três estirpes consideradas, não evidenciaram a vantagem seletiva da bacteriocinogênica sobre as demais. Observou-se, porém, a baixa capacidade de nodulação e eficiência de fixação de nitrogênio das estirpes mutantes resistentes a antibióticos em relação às mesmas estirpes normais. Verificou-se ainda, a alta capacidade competitiva das estirpes nativas em relação às estirpes normais e mutantes utilizadas como inoculante.Thirty six strains of Rhizobium phaseoli were studied in relation to several growth characteristics, ineffectiveness and effectiveness on plant host, levels of resistance to antimicrobial drugs, bacteriocin production and competitive ability among strains. Most of the strains were acid producers and showed rapid growth (3-5 days) in pure culture. Nitrogen fixation varied among strains, some showing an effectiveness of about 50%. The strain natural level of resistance in relation to seven antimicrobial drugs varied, in µg/ml, from 1 to 10 for Streptomycin, 1 to 20 for Spectinomycin, 1 to 50 for Chloramphenicol, 1 to 50 for Penicillin, 1 to 10 for Rifampicin, 0.01 to 0.1 for Tetracyclin and 1 to 5 of HgCl<sub2. A unimodal distribution was found for practically all drugs tested. lt can be them concluded that the strains are non-resistant to these drugs. Bacteriocin production was found in 25% of the strains analyzed. Such bacteriocins are very specific and their activity is maintained even after growth of the bacteria in the host plant. There is no selective advantage of the bacteriocinogenic strain in competition with two non-producers strains. On the other hand, antibiotic resistant strains showed low ineffectiveness and low effectiveness when compared with normal strains. High competitive advantage for indigenous strains in relation to normal and mutant strains used as inoculant was also observed

Sulfate and dissolved sulfide variation under low COD/Sulfate ratio in Up-flow Anaerobic Sludge Blanket (UASB) treating domestic wastewater

In this study, the dynamics of sulfate reduction and dissolved sulfide generation (S2-, HS-, H2Saq) in liquid phase was evaluated in an UASB reactor treating domestic wastewater with low COD/Sulfate content. The evaluation in the UASB reactor was performed at three sludge heights (0.25, 1.25, 2.25 taps) and effluent of the reactor. Sulfate reduction was verified in the reactor, with an average reduction of 24 % throughout the experiment period. However, the dissolved sulfide concentration in the reactor was not higher than 5.0 mg Sdiss/L. The kinetic model of first order showed good fit to describe the sulfate reduction under different COD/sulfate ratio, with K1app between 2.94x10-5 s-1 and 1.17x10-5 s-1 with correlation coefficients for data over 91%. The maximum rate to sulfate reduction was 18.0 mg SO42-/L.h-1 and small variation in COD/sulfate ratio promotes a significant change both in sulfate and sulfide concentrations

Validação de método analítico livre de acetonitrila para análise de microcistinas por cromatografia líquida de alta eficiência

Blooms of cyanobacteria represent a public health risk due to their cyanotoxins such as microcystins. Liquid chromatography techniques to separate and quantify microcystins invariably use acetonitrile as the organic component of the mobile phase. The price and availability of acetonitrile together with its elevated toxicity encourage the validation of acetonitrile-free methods of microcystin analysis. In this work, methanol was employed as the organic solvent of the mobile phase and the validation method was performed with different environmental water samples. The method showed limits of detection between 0.17 and 0.25 µg/L and of quantification between 0.55 and 0.82 µg/L for the microcystin variants: -RR, -YR, -LR, -LA