Biochemical changes accompanying brefeldin A formation in Curvularia lunata.

Extracellular brefeldin A was detected in 4% glucose--peptone--mineral salts cultures of Curvularia lunata at the start of the exponential growth phase. Some fluctuations in brefeldin A levels occurred during the exponential growth phase followed by a significant reduction in level at the stationary growth phase. Broth glucose levels decreased according to a sigmoid relationship with time whereas broth pH remained fairly constant during the exponential growth phase followed by a gradual increase into the stationary growth phase. Mycelial brefeldin A levels were low throughout the various growth phases. The principal fatty acids present in decreasing order during the exponential growth phase were linoleic, oleic and palmitic acids. However, the content of linoleic acid was significantly reduced at the onset and during the stationary growth phase.