RESUMO
The effect of the addition of (2,6-O-dimethyl)-beta-cyclodextrin (Me beta CD) during growth of Bordetella pertussis in synthetic Stainer-Scholte liquid medium (SS) on lipopolysaccharide (LPS; endotoxin) release was investigated. The Me beta CD concentration used (3 mg/ml) was chosen according to the optimal level found in previous studies to enhance major soluble antigen production. The profiles in SDS-PAGE (sodium dodecyl sulphate/polyacrylamide gel electrophoresis) of LPS extracted from cells grown in SS and SS + Me beta CD media revealed similar patterns. Although the LPS content of whole cells decreased during cell growth, yields obtained at different growth periods in cyclodextrin medium were lower than those corresponding to SS medium alone. Consequently, the level of LPS released in supernatants of both media increased during cellular growth. This amount of free LPS was higher in the cyclodextrin liquid medium and became significant at the beginning of the stationary growth phase. Binding of cyclodextrin to pertussis cells could account for the data obtained. Similar results were obtained with all species of the genus Bordetella.
Assuntos
Bordetella pertussis/crescimento & desenvolvimento , Ciclodextrinas/farmacologia , Lipopolissacarídeos/análise , Proteínas da Membrana Bacteriana Externa/análise , Bordetella pertussis/efeitos dos fármacos , Bordetella pertussis/metabolismo , Meios de Cultura , Eletroforese em Gel de Poliacrilamida , Técnicas In VitroRESUMO
The production of Bordetella pertussis extracytoplasmic filamentous haemagglutinin (FHA) and pertussis toxin (PT) in a bioreactor under stirring conditions was studied in order to investigate the effect of hydromechanical forces on yields of both antigens. It was shown that FHA loses its haemagglutinin activity when the power transmitted by the agitator and the aerator per unit volume increases, whereas PT production is not affected. The loss of FHA activity can be explained by the action of shear forces on the filamentous structure of this antigen.