RESUMO
A simple and rapid method, Microbial adhesion to hexadecane, for estimating the cell surface charge is proposed. This method is based on the determination of cell affinity to hexadecane at low ionic strength and at high ionic strength. The difference between these two affinities can provide the relative cell surface charge. The application of this method for Staphylococcus aureus and Escherichia coli show that the profile of surface charge evolution as a function ofpH was similar to these obtained by microelectrophoresis method.
Assuntos
Aderência Bacteriana , Eletricidade , Hidrocarbonetos/química , Alcanos/química , Técnicas Bacteriológicas , Membrana Celular/química , Escherichia coli/química , Escherichia coli/fisiologia , Concentração de Íons de Hidrogênio , Concentração Osmolar , Staphylococcus aureus/química , Staphylococcus aureus/fisiologia , Propriedades de SuperfícieRESUMO
Escherichia coli surface characteristics including hydrophobicity, electrophoretic mobility and surface functional groups' composition were investigated. These characteristics were determined respectively by water contact angle measurements, microelectrophoresis and x-ray photoelectron spectroscopy (XPS). The relation between the physicochemical properties and functional groups' composition was also examined. The electrophoretic mobility at pH 7 appeared to be governed on the cell surface by the (O=C) functional groups. The cell surface's hydrophilicity was associated with high levels of (C-(O.N)) and (OH-(C-O-C)) functional groups, whereas the cell surface's hydrophobicity was associated with (C-(C,H)) functional groups.
Características de superfície de Escherichia coli, tais como hidrofobicidade, mobilidade eletroforética e composição dos grupos funcionais de superfície, foram estudadas. Essas características foram determinadas por medidas de angulo de contato com água, microeletroforese e espectroscopia fotoeletrônica de raio-X (XPS), respectivamente. A relação entre as propriedades fisicoquímicas e a composição dos grupos funcionais foi também examinada. Aparentemente, a mobilidade eletroforética em pH 7 é controlada na superfície celular pelos grupos funcionais (O=C). A hidrofilicidade da superfície celular estava associada com altos níveis dos grupos funcionais [C-(O.N)] e [OH-(C-O-C)], enquanto a hidrofobicidade estava associada com os grupos funcionais [C-(C,H)].
Assuntos
Eletroforese em Microchip , Escherichia coli/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Técnicas In Vitro , Infecções Urinárias , Métodos , Análise Espectral , MétodosRESUMO
Escherichia coli surface characteristics including hydrophobicity, electrophoretic mobility and surface functional groups' composition were investigated. These characteristics were determined respectively by water contact angle measurements, microelectrophoresis and x-ray photoelectron spectroscopy (XPS). The relation between the physicochemical properties and functional groups' composition was also examined. The electrophoretic mobility at pH 7 appeared to be governed on the cell surface by the (O=C) functional groups. The cell surface's hydrophilicity was associated with high levels of (C-(O.N)) and (OH- (C-O-C)) functional groups, whereas the cell surface's hydrophobicity was associated with (C-(C,H)) functional groups.
