RESUMEN

Neem (Azadirachta indica) is an Indian tree well known for its several pharmacological activities, including antimicrobial activity. More than 300 composites have already been isolated and azadirachtin (AZA) is its main active component. In the present work, Neem leaves hydroalcoholic extracts were prepared by percolation in 96 percent ethanol different concentrations (50 percent, 60 percent, 70 percent, 80 percent and 90 percent (v/v)). The presence of AZA was tested by TLC by eluting the extracts and a standard solution of AZA through a chromatographic plate developed with anisaldehyde/sulfuric acid solution followed by heating. By HPLC, extracts elution took place on a C18 column, water:acetonitrile (60:40) as mobile phase, 1.0 mL/min flow rate and detection at λ217 nm. The extracts did not display AZA spots or peaks, however, they were tested against Gram-positive and Gram-negative bacteria, yeasts and a mold fungus. The extracts were tested in different increasing concentrations, in order to detect a dose-dependent relationship of the activity. Despite the absence of AZA, the 70 percent and 80 percent (v/v) ethanol extracts showed activity against Staphylococcus aureus. However, this activity was not dose-dependent according to Tukey's test (q0,05;3;7).

O Nim (Azadirachta indica A. Juss., Meliaceae) é uma árvore indiana conhecida por suas várias atividades farmacológicas, entre elas, a ação antimicrobiana. Dentre mais de 300 compostos já isolados, a azadiractina (AZA) é seu principal componente ativo. No presente trabalho, foram preparados extratos hidroalcoólicos de folhas de Nim em diferentes concentrações de etanol 96 por cento V/V (50 por cento, 60 por cento, 70 por cento, 80 por cento e 90 por cento (V/V)) por meio de percolação estática. A presença de AZA foi verificada por CCD, com eluição dos extratos e da solução padrão de trabalho AZA em cromatoplaca e revelação por solução de anisaldeído/ácido sulfúrico, seguida de aquecimento. Por CLAE, os extratos e da solução padrão de trabalho AZA foram eluídos em coluna C18, fase móvel água:acetonitrila (60:40), fluxo 1,0 mL/min e detecção em λ217 nm. Não foi verificada a presença de manchas ou picos correspondentes a AZA nos extratos. Entretanto, a sua atividade foi investigada contra bactérias Gram-positivas, Gram-negativas, leveduras e um fungo filamentoso. Os extratos foram testados em diferentes concentrações para avaliar a relação dose-resposta. Apesar da ausência de AZA, os extratos hidroalcoólicos a 70 por cento e 80 por cento (V/V) de etanol 96 por cento apresentaram atividade contra Staphylococcus aureus. Porém, não houve relação dose-efeito, de acordo com o teste de Tukey (q0,05;3;7).

RESUMEN

We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms.

O objetivo deste trabalho foi estudar as comunidades de leveduras associadas a frutos, cogumelos, exudatos de árvores e moscas do gênero Drosophila, em dois fragmentos de Mata Atlântica no Estado de Minas Gerais, Brasil. Foram coletadas 456 amostras no Parque Estadual do Rio Doce e 142 na Estação Ecológica da Universidade Federal de Minas Gerais. Destas amostras foram obtidas 608 isolados de levedura, distribuídas em 71 espécies. Entre os isolados obtidos a partir do Parque Estadual do Rio Doce, 17 foram provenientes de frutos, 12 de cogumelos, 13 de exudatos de árvores e 299 de Drosophila spp. A Estação Ecológica da Universidade Federal de Minas Gerais possibilitou a obtenção de 24 isolados de frutos e 243 de Drosophila spp. Foram observadas comunidades distintas de leveduras associadas a Drosophila, frutos, cogumelos e exudatos de árvores. O maior número de espécies foi obtido em drosófilas, sugerindo que estas moscas são vetores naturais destes microrganismos.

Asunto(s)

RESUMEN

We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms.

RESUMEN

Staphylococcus aureus causes disease in humans and a wide array of animals. Of note, S. aureus mastitis of ruminants, including cows, sheep, and goats, results in major economic losses worldwide. Extensive variation in genome content exists among S. aureus pathogenic clones. However, the genomic variation among S. aureus strains infecting different animal species has not been well examined. To investigate variation in the genome content of human and ruminant S. aureus, we carried out whole-genome PCR scanning (WGPS), comparative genomic hybridizations (CGH), and the directed DNA sequence analysis of strains of human, bovine, ovine, and caprine origin. Extensive variation in genome content was discovered, including host- and ruminant-specific genetic loci. Ovine and caprine strains were genetically allied, whereas bovine strains were heterogeneous in gene content. As expected, mobile genetic elements such as pathogenicity islands and bacteriophages contributed to the variation in genome content between strains. However, differences specific for ruminant strains were restricted to regions of the conserved core genome, which contained allelic variation in genes encoding proteins of known and unknown function. Many of these proteins are predicted to be exported and could play a role in host-pathogen interactions. The genomic regions of difference identified by the whole-genome approaches adopted in the current study represent excellent targets for studies of the molecular basis of S. aureus host adaptation.

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RESUMEN

Four strains of an asexual arthroconidial yeast species were isolated from Drosophila flies in two Atlantic rain forest sites in Brazil and two strains from oak tasar silkworm larvae (Antheraea proylei) in India. Analysis of the sequences of the D1/D2 large subunit rRNA gene showed that this yeast represented a novel species of the genus Geotrichum, described as Geotrichum silvicola sp. nov. The novel species was related to the ascogenous genus Galactomyces. The closest relatives of Geotrichum silvicola were Galactomyces sp. strain NRRL Y-6418 and Galactomyces geotrichum. The type culture of Geotrichum silvicola is UFMG-354-2T (=CBS 9194T=NRRL Y-27641T).

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