195 resultados para dimorphic pathogenic fungi


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The ants of genus Atta belong to the Attine tribe (order Hymenoptera, family Formicidae, subfamily Myrmicinae) and are commonly known as leaf-cutting ants for having the habit of cutting several vegetable species used as substrate for growing mutualistic fungus (Agaricales: Lepiotaceae). Recent studies showed that, in addition to that, other fungi may occur in the nests in a dorment state or participate in the functioning dynamic of this symbiosis. Researches related to surveys of fungus biodiversity in nests of different Atta species have found important phytopathogenic representatives. In Brazil, studies about integrated management of plagues, developed by Embrapa Meio Ambiente (Embrapa Environment), point out the need of higher investments in projects that involve the phytopathogenic transmission by insects in order to reduce costs to control them or minimize environmental impact. The purpose of this study was to broaden the knowledge about the ecology of these fungi, isolating and identifying species associated with Attine tribe ants, thus understanding the scope of pathogenic and phytopathogenic species spread by these ants. For that reason, gynes were collected from Atta laevigata and Atta capiguara anthills located at Unesp Botucatu (São Paulo, Brazil) campus. In order to isolate the fungus, the mineral oil floating technique was used. The identification of the isolated fungi was done based on microscopic and molecular characteristics using DNA ribosomal sequencing. The most highly abundant genera found so far were: Cladosporium, Exophiala, Penicillium, Acremonium, Phialophora and Teratosphaeria. Representatives of the genera Exophiala, Phialophora and Cladosporium may be human pathogens, whereas Teratosphaeria and Penicillium are related to diseases in Eucalyptus and citric fruits, respectively. The results show that these ants may host important fungal species besides the ones already... (Complete abstract click electronic access below)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Soil management practices are konwn to affect the biomass and enzyme activities of microbial soil communities. To assess whether burning of sugarcane prior to harvesting affects the community of soilborne fungi, we collected soil simples in two sites: burned sugarcane culture prior harvesting (BS) and non-burned sugarcane culture (NBS). A total of 75 filamentous fungal isolates were recovered from soils in both sites. Trichoderma was the most prevalent genus in both sites, followed by Fusarium, Cunninghamella and Aspergillus. The Sorensen's index (0.60) suggested a slight difference in fungi associated with both areas, with high number of fungal isolates found on BB soil. The abundance of Trichoderma isolates in NBS soil was higher than BS soil; however, the abundance of Fusarium, Aspergillus and Cunninghamella was higher in the latter type of soil. In addition, fungi isolated from BS soil showed the highest production of xylanase and laccase in comparision with fungi isolated form NBS soil. Our results indicate that the different types of sugarcane harvesting apparently did not interfere with the diversity of fungal communnities as revealed by culture-dependent methods. In addition, our data indicates the potencial of fungi from soils of sugarcane crops to produce relevant enzymes related to biomass conversion.

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Fungi isolated from marine organisms have been shown to produce several interesting secondary metabolites with important biological activities. Such chemical diversity may be associated to environmental stress conditions and may represent an important source of NCE for bioprospection. Quinolactins belong to a rare fungi-alkaloid class with a unique N-methyl-quinolone moiety fused to a lactam ring and present several bioactivities1. Fungi strain Dm1 was isolated from red alga Dichotomaria marginata, collected from Brazil SE coast, and was grown in sterile rice solid media at 26oC 2, which was then extracted with MeOH. The MeCN fr. from the MeOH extract was chromatographed over Sephadex LH-20 and fr. 4 afforded quinolactin (QL) alkaloids B1, B2 and A, whereas fr. 5 afforded quinolactin D1 after purification by HPLC-DAD. Structural determination of pure compounds was based on HRMS, UV, and NMR spectral analyses, in addition to comparison with literature data and Antimarin® databank. UV data indicated the presence of similar chromophores with λmax at ca. 247 and 320nm. HRMS and tandem MS analyses using both negative and positive ion modes for the isolated compounds indicated their molecular formula and structural features, as for QL B1: C15H16O2N2 [M+H 257], which showed one fragment at m/z 214 [-CHNO]; QL B2: C15H16O3N2 [M+H 273], with product ions at m/z 230 [-CHNO.] and m/z 186 [-C4H9NO.]; for QL A: C16H18N2O2 [M+H 271], which presented one ion at m/z 214, due to loss of fragment (-C4H9) from the molecular ion; and for QL D1: C16H18N2O3 [M+H 287], with product ions at m/z 186 [-CHNO] and m/z 230 [-C4H9]. Such data suggested fragmentation proposals, e.g. for Quinolactin B1 (Fig. 1), which confirmed the structures of the isolated quinolactins, and may represent an important contribution for the sustainable exploration of marine biodiversity.

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The presence of environmental mycobacteria on surfaces in two public health institutions, namely a health center and a hospital in upstate São Paulo (Brazil), was identified by polymerase chain reaction-restriction enzyme analysis (PRA). The possible sources of contamination by these microorganisms were evaluated, contributing to epidemiology studies. Methods: From June 2005 to June 2006, a total of 632 samples were collected from exposed surfaces, such as washbasins, drinking fountains, and other accessible sites, and the mycobacteria present in the samples were isolated and cultured. Results: Sixty-five mycobacteria were isolated from the 632 samples; 47 of which were detected in samples from the health center and 18 in samples collected from the hospital. The isolates were identified by DNA restriction patterns obtained by PRA, and potentially pathogenic species were found to be prevalent among the identified mycobacteria. This study shows that the PRA technique can be employed as a fast and easy method for identification of nontuberculous mycobacteria in public areas. Conclusions: The isolation of environmental mycobacteria from the two health institutions demonstrates that these surfaces are reservoirs of potentially pathogenic mycobacteria and indicates the need for continuous maintenance and monitoring. These data will add to the study of the epidemiology of these microorganisms.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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The antimicrobials products from plants have increased in importance due to the therapeutic potential in the treatment of infectious diseases. Therefore, we aimed to examine the chemical characterisation (GC-MS) of essential oils (EO) from seven plants and measure antibacterial activities against bacterial strains isolated from clinical human specimens (methicillin-resistant Staphylococcus aureus (MRSA) and sensitive (MSSA), Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) and foods (Salmonella Enteritidis). Assays were performed using the minimal inhibitory concentration (MIC and MIC90%) (mg/mL) by agar dilution and time kill curve methods (log CFU/mL) to aiming synergism between EO. EO chemical analysis showed a predominance of terpenes and its derivatives. The highest antibacterial activities were with Cinnamomun zeylanicum (0.25 mg/mL on almost bacteria tested) and Caryophyllus aronzaticus EO (2.40 mg/mL on Salmonella Enteritidis), and the lowest activity was with Eugenia uniflora (from 50.80 mg/mL against MSSA to 92.40 mg/mL against both Salmonella sources and P aeruginosa) EO. The time kill curve assays revealed the occurrence of bactericide synergism in combinations of C. aromaticus and C. zeylanicum with Rosmarinus. officinalis. Thus, the antibacterial activities of the EO were large and this can also be explained by complex chemical composition of the oils tested in this study and the synergistic effect of these EO, yet requires further investigation because these interactions between the various chemical compounds can increase or reduce (antagonism effect) the inhibitory effect of essential oils against bacterial strains.

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Isolates of Paracoccidioides brasiliensis and Paracoccidioides lutzii, previously characterized by molecular techniques, were identified for the first time by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). All isolates were correctly identified, with log score values of >2.0. Thus, MALDI-TOF MS is a new tool for differentiating species of the genus Paracoccidioides.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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