RESUMO
Toxoplasma gondii membrane fluidity was investigated by fluorescence polarization. We used 1,6-diphenyl 1,3,5-hexatriene (DPH) as a fluorescent hydrophobic probe. Fluorescence anisotropy (r) and degree of order (s) showed high fluidity properties. Chemical analysis was performed on this parasite. We found a low cholesterol/phospholipid ratio, many unsaturated fatty acids chains, and high phosphatidylcholine and low sphingomyelin amounts. These results were in good agreement with the observed high fluidity. This may be related to the great adaptability of Toxoplasma gondii in infesting a wide variety of host cells.
Assuntos
Fluidez de Membrana , Toxoplasma/fisiologia , Animais , Membrana Celular/fisiologia , Colesterol/análise , Difenilexatrieno , Ácidos Graxos/análise , Polarização de Fluorescência , Cinética , Lipídeos/análise , Fosfolipídeos/análise , Toxoplasma/análise , Toxoplasma/crescimento & desenvolvimentoRESUMO
Tachyzoites of Toxoplasma gondii have been radioiodinated under various conditions with or without lactoperoxidase, with glucose oxidase being used to generate hydrogen peroxide. Erythrocytes were iodinated simultaneously as a control. In our conditions, tachyzoites were more intensely labelled in the absence of lactoperoxidase. This result can be explained by the existence of an intrinsic peroxidase activity which interfere with the exogenously added enzyme during surface radioiodination.