900 resultados para LEUCO-CRYSTAL VIOLET
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs) of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at subMICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that subMICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since subMICs may promote colonization of the oral cavity by S. mutans.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Pós-graduação em Medicina Veterinária - FCAV
Resumo:
Coordenação de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)
Resumo:
Objective In studies on Candida albicans adhesion to surfaces, diverse protocols have been used for collection and preparation of saliva samples. Thus, this study investigated whether variations in the centrifugation parameters and number of donors of saliva would influence the adhesion of C. albicans to a denture base resin. Methods Resin acrylic samples (n = 72) were made and then divided into four groups: (a) control – specimens were left without preconditioning in saliva; (b) three experimental groups, in which the specimens were preconditioned with saliva collected from 15 volunteers and centrifuged at 12 000 g for 5 min (G1); from 15 volunteers and centrifuged at 18 000 g for 30 min (G2); and from one volunteer and centrifuged at 12 000 g for 5 min (G3). Candida adhesion was evaluated by both the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction method and crystal violet staining. Data were analyzed by one-way analyses of variance (P = 0.05). Results For XTT reduction assay, groups G2, G3, and control were not significantly different, whereas group G1 showed significantly higher absorbance value than control. For crystal violet staining there were no significant differences among all groups. Conclusion Variations in the centrifugation parameters and number of donors of saliva may influence C. albicans adhesion to denture base resins.
Resumo:
Pós-graduação em Reabilitação Oral - FOAR
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Background: Solobacterium moorei is a volatile sulfide compound (VSC)-producing Gram-positive anaerobic bacterium that has been associated with halitosis. The aim of this study was to investigate the effects of green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) on growth and severalhalitosis-related properties of S. moorei.Methods: A microplate dilution assay was used to determine the antibacterial activity of green tea extract and EGCG against S. moorei. Their effects on bacterial cell membrane integrity were investigated by transmission electron microscopy and a fluorescence-based permeability assay. Biofilm formation was quantified by crystal violet staining. Adhesion of FITC-labeled S. moorei to oral epithelial cells was monitored by fluorometry. The modulation of beta-galactosidase gene expression in S. moorei was evaluated by quantitative RT-PCR.Results: The green tea extract as well as EGCG inhibited the growth of S. moorei, with MIC values of 500 and 250 mu g/ml, respectively. Transmission electron microscopy analysis and a permeabilization assay brought evidence that the bacterial cell membrane was the target of green tea polyphenols. Regarding the effects of green tea polyphenols on the S. moorei colonization properties, it was found that biofilm formation on EGCG-treated surfaces was significantly affected, and that green tea extract and EGCG can cause the eradication of pre-formed S. moorei biofilms. Moreover, both the green tea extract and EGCG were found to reduce the adherence of S. moorei to oral epithelial cells. The beta-galactosidase activity of S. moorei, which plays a key role in VSC production, was dose-dependently inhibited by green tea polyphenols. In addition, EGCG at 1/2 MIC significantly decreased the beta-galactosidase gene expression.Conclusion: Our study brought evidence to support that green tea polyphenols possess a number of properties that may contribute to reduce S. moorei-related halitosis. Therefore, these natural compounds may be of interest to be used to supplement oral healthcare products.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR