Fig.1.

Lipid droplets are ubiquitous. All eukaryotes produce and often accumulate neutral lipids as cytoplasmic or secreted particles. A: In budding yeast (Saccharomyces cerevisiae), lipid droplets (envisaged here by fluorescence staining with Nile red) accumulate as cells approach stationary phase. B: The accumulation of fatty deposits in the liver (oil red O staining; Liu and Sturley, unpublished data) is the pathological determinant of steatosis and nonalcoholic fatty liver disease (NAFLD). C, D: Lipid deposition in algae (e.g., diatoms stained with Nile red grown in media lacking and containing free fatty acids, respectively; Ruggles and Sturley, unpublished data) form the basis of our oil reserve. E: A similar structure, triglyceride-rich lipoproteins (negative staining, electron micrograph; Iqbal and Hussain, unpublished data), such as very low density lipoproteins, form in the ER lumen and accumulate in plasma of many patients at risk for coronary artery disease. OA, oleic acid.