956 resultados para PATHOGENIC FUNGUS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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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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Polygalacturonases are enzymes involved in the degradation of pectic substances, being extensively used in food industries, textile processing, degumming of plant rough fibres, and treatment of pectic wastewaters. Polygalacturonase (PG) production by thermophilic fungus Thermoascus aurantiacus on solid-state fermentation was carried out in culture media containing sugar cane bagasse and orange bagasse in proportions of 30% and 70% (w/w) at 45°C for 4 days. PG obtained was purified by gel filtration and ion-exchange chromatography. The highest activity was found between pH 4.5 and 5.5, and the enzyme preserved more than 80% of its activity at pH values between 5.0 and 6.5. At pH values between 3.0 and 4.5, PG retained about 73% of the original activity, whereas at pH 10.0 it remained around 44%. The optimum temperature was 60–65°C. The enzyme was completely stable when incubated for 1 hour at 50°C. At 55°C and 60°C, the activity decreased 55% and 90%, respectively. The apparent molecular weight was 29.3 kDa, Km of 1.58 mg/mL and Vmax of 1553.1μmol/min/mg. The presence of Zn+2, Mn+2, and Hg+2 inhibited 59%, 77%, and 100% of enzyme activity, respectively. The hydrolysis product suggests that polygalacturonase was shown to be an endo/exoenzyme.
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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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.