LIPID DISTRIBUTION IN THE CELL 605 



they made up about three-fourths of the total lipid. The essential lipid 

 was composed of phospholipid to the extent of over 90%, sphingomyelin 

 making up less than 5% of the total. Butter yellow was shown to effect a 

 change in the structure of the liver cell, as indicated by the alterations in 

 the lipid pattern. Nuclei isolated from tumorous liver cells exhibited a 

 greatly reduced phospholipid concentration and an increased amount of 

 cholesterol ester. These authors suggest that the pathological derange- 

 ment of phospholipid occurs primarily in the nucleus. 



In a further examination of the nature of cell nuclei, Wang et al. 3Si dem- 

 onstrated that the lipid components were present in combination with 

 protein. These lipoproteins of the nuclei of rat liver, calf liver, ox spleen, 

 and chicken erythrocytes were found to contain approximately 10% of 

 lipids. In the case of those prepared from rat and calf liver, 20 to 30% of 

 the dry weight was found to consist of the lipoprotein. 



The lipid composition of mitochondria has also been studied. Mayer 

 and Schaeffer, 385 - 386 employing relatively crude methods, reported that mito- 

 chondria consist largely of phospholipids. Using the modern technic of 

 gravitational fractionation, Bensley 387 ' 388 reported that 35% of the guinea 

 pig mitochondria is lipid. Phospholipid (as lecithin) was shown to account 

 for 45 to 58% of the total lipid. 389 On the other hand, Chargaff 390 noted 

 that the phosphatides in rabbit liver made up only a small part of the ex- 

 tracted lipids of the mitochondrial fraction. 



Chargaff 390 listed the following composition for these mitochondria, ex- 

 pressed in per cent of dry matter: phosphatides, 4.0; glycerides (as tri- 

 olein), 5.4; cholesterol, 1.2; cerebrosides, 3.3; lysophosphatides (as pal- 

 mityl lysolecithin), 4.3; extraction residue, 72.0. However, Swanson and 

 Artom 391 have called attention to the fact that the lipids in mitochondria 

 are present in unusually firm combinations with protein, rendering their 

 complete extraction very difficult. Phospholipids were found to be pres- 

 ent to the extent of 79% in the lipids extracted from the trichloroacetic 

 acid precipitate of mitochondria. Neutral fat and other lipids made up 

 17%, and cholesterol comprised the remaining 4%. The phospholipid 

 fraction was composed of 45% lecithin, 8% sphingomyelin, and 47% non- 



384 1. Y. Wang, M. J. Carver, R. H. Ramsey, A. J. Funckes, and L. E. Thomas, 

 Federation Proc, 11, 306 (1952). 



385 A. Mayer and G. Schaeffer, J. physiol. et path, gen., 16, 325-336 (1914). 



386 A. Mayer and G. Schaeffer, J. physiol. et. path gen., 16, 344-359 (1914). 



387 R. R. Bensley, Anat. Record, 69, 341-352 (1937). 



388 R. R. Bensley and N. L. Hoerr, Anat. Record, 60, 449-455 (1934). 



389 R. R. Bensley, Science, 96, 389-393 (1942). 



390 E. Chargaff, J. Biol. Chem., lJfi, 491-504 (1942). 



391 M. A. Swanson and C. Artom, J. Biol. Chem., 187, 281-287 (1950). 



