Pathway of C6-NBD-Ceramide on the host cell infected with Toxoplasma gondii.

Fluorescence microscopy, with dyes analog of ceramide, and transmission electron microscopy, were used to analyze lipid traffic during interaction of Toxoplasma gondii with host cells. It is C6-NBD-Ceramide (C6-NBD-Cer), a fluorescent analog of ceramide, stained the Golgi complex where was metabolized into fluorescent sphingolipid and glucosylceramide, and translocated via the Golgi complex to the plasma membrane of living cells. In uninfected cells, C6-NBD-Cer initially concentrated at the perinuclear region, and after its fluorescent products were present in the cytoplasm and the plasma membrane. In infected cells, the probe initially is stained the Golgi complex. After 4 hours incubation with C6-NBD-Cer, the parasites within the parasitophorous vacuole began to be stained, and at 5 hours incubation, the parasites are completely fluorescent. The Golgi complex, as revealed by fluorescent probe and electron microscopy, maintained its perinuclear position throughout the evolution of intracellular parasitism. These results suggested that the intracellular parasite used the lipid pathway of the host cell.