The fatty acid composition of C. elegans TAG revealed a high content
of dietary fatty acids in lipid droplets. This is consistent with a previous
study showing that TAG fractions contained relatively smaller proportions
of de novo synthesized fatty acids compared to phospholipid fractions
[49]. Similarly, in yeast lipid droplets the cholesterol ester/TAG
ratio depends on carbon source [37]. The low amounts of sterols in
C. elegans lipid droplets is likely a reflection of dietary requirements, in
which very low sterol levels are required for growth [49]. It has previously
been shown that cholesterol levels are very low in C. elegans membranes
[38,50], and the main function of cholesterol is for the
production of steroid hormones regulating growth and reproduction,
rather than as structural components of cellular membranes [51].