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Structure and Function of Sterols in Fungi

1989; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-12-024923-7.50007-8

0065-2849

John D. Weete,

Natural product bioactivities and synthesis

This chapter discusses the structure and function of sterols in fungi. The distribution of sterols among fungi follows the taxonomic separation of fungi at the subdivision level. The Mastigomycotina, or lower fungi, produce mainly cholesterol and/or its C-24 alkyl and/or alkylidene derivatives, but no ergosterol. There is less distinction among fungi at the class level with respect to sterol composition among the Mastigomycotina. Fucosterol is a major sterol of many sterol-producing Oomycetes and may be accompanied by cholesterol and 24-methylene cholesterol. Cholesterol is produced by some but not all Chytridiomycetes, which, along with the Hypochytriomycetes, have 24-alkyl rather than 24-alkylidene derivatives as major sterols. It is well-known that the pythiaceous fungi (Oomycetes) do not produce sterols because they cannot carry out the epoxidation of squalene, and it is believed that Plasmodiophoromycetes, which are obligate parasites, also do not produce sterols. Sterols are synthesized by enzymes located mainly in the endoplasmic reticulum, but they do not tend to accumulate there or in endomembranes derived from the endoplasmic reticulum.