CELL LIPIDS 47 



preparation of the mycelium may contribute to the high apparent acid 

 value of fungal lipids. 



The fatty acid composition of some fungal lipids is summarized in 

 Table 6. These and other data (10, 53, 97) show that the 16- and 18- 

 carbon acids are the most abundant, and that with few exceptions the 

 unsaturated acids — especially oleic and linoleic — predominate. The 

 low Reichert-Meissl number of fungal lipids reflects the relative ab- 

 sence of the lower fatty acids (10). 



The antibiotic activity of a strain of Penicillium crustosum has been 

 traced to the presence of linoleic acid in its mycelium (142). 



A number of fatty acids which are not known to be constituents of 

 fats have been isolated from fungi. Three of these — agaric, spiculis- 

 poric, and mineoluteic acids — are long chain hydroxy-tricarboxy acids 

 similar to some of the lichen acids (136). Actinomyces (Streptomyces) 

 flavas forms a wax, the dodecyl ester of 5-keto-octadecanoic acid (82), 

 and 6-keto-octadecanoic acid has been isolated from sporophores of 

 Lactarius spp. (21). The ustilic acids, identified as di- and trihydroxy- 

 hexadecanoic acids, occur as constituents of the glucolipid ustilagic 

 acid, a metabolic product of Ustilago zeae (98). 



The phosphatides, determined by their solubility, are usually less 

 than 10 per cent of the total lipid, but in Blastomyces dermatitidis 

 may amount to as much as one-third of the lipid fraction (122). In 

 Aspergillus spp. the phosphatides constitute at least 0.15 to 0.7 per 

 cent of the dry weight (138, 193). 



Excluding earlier studies, reviewed by Czapek (30), which employed 

 inadequate methods, well-characterized phosphatides are a lecithin and 

 a cephalin from Aspergillus sydowi (193) and a lecithin and a cephalin, 

 not identical with these, from Blastomyces dermatitidis (122). These 

 have been characterized by their physical properties and their hydroly- 

 sis products; structures have not been determined. In addition, a 

 cephalin fraction from Neurospora crassa has been described and evi- 

 dently comprises more than one compound, since both serine and 

 ethanolamine are present (39). The phospholipid fraction of Peni- 

 cillium chrysogenum yields inositol phosphate (84), and an inositol 

 phospholipid occurs in Neurospora crassa (57). Similarly the positive 

 Molisch reaction of the acetone-insoluble lipids of several fungi indi- 

 cates that a carbohydrate-containing phospholipid may be present 

 (122). 



The mycelium of Aspergillus sydowi contains at least 0.1-0.4 per 

 cent of a cerebrin (19); this partially characterized nitrogenous lipid 

 is probably identical with that isolated earlier from yeast, Claviceps 

 purpurea, and from the sporophores of several basidiomycetes. The 



