engleski

The infuence of carbon source on the level and composition of ceramides of the Candida lipolytica yeast

Candida lipolytica yeast was grown batchwise on two different carbon sources, glucose and n-hexadecane. Free ceramides were quantitatively isolated from sphingolipid fractions of total lipids by a combination of column chromatography and preparative thin-layer chromatography. Their composition, after acid methanolysis, was analysed by gas-liquid chromatography. The ceramide content accounted for 2.6% of the total cell lipids in hexadecane-grown cell, which was 1.5 times higher then in glucose-grown cells. The fatty acids composition of ceramides was characterized by the predominance of fatty acids shorter then 20 carbon atoms and by high concentrations of fatty acids with 16 carbon atoms after growth on both carbon sources. The dominant fatty acid was hydroxylated 16:0 in glucose-grown cells and 16:0 in the hexadecane-grown cells. The striking finding was the low degree of fatty acid hydroxylation and relatively high portion of odd-number fatty acids in ceramide of the n-hexadecane-grown cells. The ceramide contained an unusual long-chain base composition. In hexadecane-grown cells more then 60% of the long-chain bases were C19 phytosphingosine. In glucose-grown cells more then one-half of the total long-chain bases were tetrahydroxy bases, 4,5-dihydroxysphinganine and 4,5-dihydroxyeicosasphinganine.

Candida lipolytica; sphingolipids; ceramides; fatty acids; long-chain bases

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