Sphingomyelin synthesis in Fasciola hepatica

Free ceramides of Echinococcus multilocularis metacestodes

Free ceramides were isolated and purified from the metacestodes of Echinococcus multilocularis. Two different fractions were obtained by preparative thin-layer chromatography. Their structure was determined by gas chromatography and electron impact mass spectrometry of trimethylsilylated derivatives. The ceramide with the higher thin-layer chromatographic migration rate contained exclusively erythro-sphinganine associated with saturated C16, C18 and very-long-chain fatty acids (up to C30) and unsaturated C24 fatty acid. The second ceramide contained 90.3% sphingosine and 9.7% sphinganine associated with saturated C16 and C24 and unsaturated C18 and C24 fatty acids. These findings were discussed with regard to the structure and metabolic pathway of neutral and acid glycosphingolipids found in the metacestodes.

Sphingomyelin synthesis in Ascaridia galli

Adult Ascaridia galli incorporate label from [U-14C] serine into various intermediates of sphingomyelin synthesis (ketosphinganine, sphinganine, sphingosine, ceramide and sphingomyelin). From the results it is concluded that A. galli possesses the five enzymes involved in sphingomyelin synthesis, namely: serine palmitoyltransferase, 3-ketosphinganine reductase, flavoprotein sphinganine reductase, sphingosine acyltransferase and ceramide choline phosphotransferase.

Replacement of vertebrate serum with lipids and other factors in the culture of invertebrate cells, tissues, parasites, and pathogens

Culture medium supplementation with vertebrate serum results in the selection of fibroblastoid insect cell lines and a general decline during continuous subculturing of both morphologic and functional differentiation of the surviving cells. Essential lipid mixtures can substitute for vertebrate serum in the culture of insect and some vertebrate cells, tissues, parasites, and pathogens. The provision of sterols and essential (with nonessential) polyunsaturated fatty acids as phospholipids in oxidation-protected peptoliposomes or proteoliposomes allows cells in culture to duplicate in vivo specific membranes more accurately. Such lipid-corrected membranes allow cultured cells to communicate with neighboring cells through the extracellular matrix, effectively transmit hormonal signals directly and via receptor control, and respond with various tissue-specific functions and differentiation states as directed.