Glycine betaine: Reserve form of choline in Penicillium fellutanum in low-sulfate medium

In spite of choline's importance in fungal metabolism, its sources in cytoplasm have not been fully established. ¹³C nuclear magnetic resonance analysis of mycelial extracts from day-5 Penicillium fellutanum cultures showed that, as well as choline-O-sulfate, intracellular glycine betaine is another reserve form of choline, depending on the availability of sulfate in the culture medium. These observations are discussed relative to the multiple roles of choline and its precursors in P. fellutanum.