The surface charge of Toxoplasma gondii: a cytochemical and electrophoretic study.

摘要: The surface charge of Toxoplasma gondii tachyzoites was evaluated by means binding colloidal iron hydroxide particles at pH 1.8, cationized ferritin 7.2 and ruthenium red to the cell surface, as visualized electron microscopy direct measurements electrophoretic mobility (EPM) cells suspended in solutions different ionic strength pH. At 7.2, T. has a negative with mean EPM of--1.1272 +/- 0.0917 micron.s-1 X V-1 cm. No significant difference observed between living 25 degrees C that glutaraldehyde-fixed cells. lower pH, there is decrease charge, an isoelectric point 3.5. higher (greater than 10), increase reaching of--1.5675 0.0848 cm 7.2. These results indicate contains both negatively positively charged dissociating groups. Binding throughout observed. However, when parasites were incubated 4 presence some showed uniform distribution label, others patch-distribution still no label seen, indicating process shedding anionic sites. Colloidal hydroxyde did not bind gondii. Incubation neuraminidase from Clostridium perfringens or Vibrio cholerae proteolytic enzymes (trypsin protease) interfere charge.(ABSTRACT TRUNCATED AT 250 WORDS)