Navegando por Assunto "Aspergillus flavus"

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Acesso aberto (Open Access)
Avaliação do efeito antifúngico do óleo resina e do óleo essencial de copaíba (Copaifera multijuga Hayne)
(2011) DEUS, Ricardo Jorge Amorim de; ALVES, Claudio Nahum; ARRUDA, Mara Silvia Pinheiro
Copaifera multijuga Hayne oil in natura and its fractions were evaluated as to their fungitoxic activities against five filamentous fungus species belonging to the genus Aspergillus and three yeast species of the genus Candida. Oleoresin and essential oil concentrations ranging from 0.08 mg mL-1 to 1.6 mg mL-1 were used for qualitative and quantitative analyses. The samples were placed onto 5mm-diameter paper discs distributed on Sabouraud's medium in Petri dishes inoculated with spores of the microorganisms and incubated at 28ºC for 10 days. A solution containing 1.6 mg mL-1 miconazole nitrate was used as positive control. Qualitative results showed that the oleoresin presented good activity, while a fraction of the essential oil was highly effective against Candida parapsilosis IOC-2882, Aspergillus flavus IOC-3874 and A tamarii IOC-187 with 16.0±1.4 mm, 19.5±2.1 mm and 12.5±3.5 mm inhibition halos, respectively. The quantitative evaluation showed that 0.3 mg mL-1 oleoresin inhibited the growth of Aspergillus flavus and Candida parapsilosis, while 0.08 mg mL-1 of the essential oil fraction reached this same activity.
Acesso aberto (Open Access)
Biotransformation of chalcones by the endophytic fungus Aspergillus flavus isolated from Paspalum maritimum trin
(2011-07) CORRÊA, Marivaldo José Costa; NUNES, Fátima Miranda; BITENCOURT, Heriberto Rodrigues; BORGES, Fábio Cardoso; GUILHON, Giselle Maria Skelding Pinheiro; ARRUDA, Mara Silvia Pinheiro; MARINHO, Andrey Moacir do Rosário; SANTOS, Alberdan Silva; ALVES, Claudio Nahum; BRASIL, Davi do Socorro Barros; SANTOS, Lourivaldo da Silva
The fungus Aspergillus flavus isolated as endophytic of the plant Paspalum maritimum Trin. was evaluated for its potential application in biotransformation reactions. The compounds chalcone (1), 3,4,5-trimethoxychalcone (2) and 2,3,4,4'-tetramethoxychalcone (3) were biotransformed, respectively, in dihydrochalcone (4), 3,4,5-trimethoxydihydrochalcone (5) and 2,3,4,4'-tetramethoxydihydrochalcone (6). The structures were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and MS analysis. The dihydrochalcones 5 and 6 are new compounds.
Acesso aberto (Open Access)
Biotransformation of sucrose into 5-hydroxy-2-hydroxymethyl-γ-pirone by Aspergillus flavus
(2010-09) FERREIRA, Nelson Rosa; SARQUIS, Maria Inez de Moura; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
The sucrose hydrolysis and the preference of consumption of glucose instead of fructose were investigated for the production of 5-hydroxy-2-hydroxymethyl-γ-pyrone (HHMP) in the presence of Aspergillus flavus IOC 3974 cultivated in liquid Czapeck medium. Standardized 0.5g of pellets were transferred as inoculum into twelve conical flasks of 250 ml containing 100 ml of medium with different sucrose concentration, which was kept at 120 rpm and 28"C for 16 days without pH adjustment. Aliquots of 500μl of the broth culture were withdrawn at 24 h intervals and analyzed. The major yield of HHMP was 26g l-1 in 120g l-1 of sucrose. At these conditions, A. flavus produced an invertase capable of hydrolyzing 65% of total sucrose concentration in 24h, and an isomerase capable of converting fructose into glucose. In this work, it focused the preference for glucose and, then, of fructose by A. flavus and the strategy used to produce HHMP.