Navegando por Autor "Ribon, Andréa O. B."
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Item Plant extracts display synergism with different classes of antibiotics(Anais da Academia Brasileira de Ciências, 2019-05) Silva, Danielle M.; Costa, Priscilla A. da; Ribon, Andréa O. B.; Purgato, Gislaine A.; Diaz-Muñoz, Gaspar; Diaz, Marisa A.N.One manner in which plant-derived compounds exert their antibiotic potential is the synergism, a positive interaction between two compounds. Studies indicate that the use of plant extracts combined with antimicrobials may promote a significant reduction of the minimum inhibitory concentrations of antibiotics for bacterial strains. This study aimed to evaluate the activity of plant extracts and antibiotics as well as their combination on Staphylococcus aureus. The activity of 15 plant extracts was evaluated using diffusion assay. The minimum inhibitory concentrations (MICs) and the interactions between the extracts and antibiotics as well as compound emodin were evaluated with the checkerboard method. The active extracts were a hexane extract of the leaves of Baccharis dracunculifolia and the ethanol extracts of the leaves of Plectranthus ornatus, Inga edulis, Salvia officinalis and Senna macranthera. The Plectranthus ornatus extract displayed synergism with ampicillin (a β-lactam), kanamycin and gentamicin (aminoglycosides), with 8-fold reductions in the MIC. The same reduction was observed for the extracts of Salvia officinalis and Senna macranthera, which displayed the lowest MIC. Using these combinations resulted in a reduction in the minimum dose required for effective antimicrobial effects, which is interesting because it may decrease both the risk of side effects and the costs of treatment.Item Structural organization of polygalacturonase-encoding genes from Penicillium griseoroseum(Genetics and Molecular Biology, 2002) Ribon, Andréa O. B.; Queiroz, Marisa V.; Araújo, Elza F. deThe pectinolytic system of Penicillium griseoroseum has been studied as a model to investigate aspects of gene organization in filamentous fungi. Here we show that the endopolygalacturonase-coding genes previously isolated exist as single copies in the fungus genome. DNA blot analysis revealed the presence of corresponding genes in other Penicillium species, although only one or two genes were found in opposition to the endoPG gene family reported for other filamentous fungi. The nucleotide and amino acid sequences of Penicillium PG genes of retrieved from data banks were compared for intron length and number, codon usage, and consensus sequences for translation initiation sites. The introns are conserved in the same position, although there was no conservation of their nucleotide sequences. Other sequence features resemble those seen in Aspergillus and Neurospora genes