Production and characterization of Amanitin toxins from a pure culture of Amanita exitialis.

Amanita exitialis Zhu L. Yang and T.H. Li is a lethal mushroom species recently isolated in Guangdong Province, China. In this report, a pure culture of this species was obtained for the first time. To confirm the identity of the pure culture, the internal transcribed spacer regions of the nuclear ribosomal DNA of the pure culture and of a typical fruiting body of the species were sequenced and compared. Further, amatoxins produced by pure cultures were analyzed and characterized by high-performance liquid chromatography and mass spectrometry analysis. The results showed that the pure cultures produced 728.3 +/- 43.8 microg g(-1) (dry matter) of alpha-Amanitin and 60.0 +/- 20.7 microg g(-1) (dry matter) of beta-Amanitin, respectively, a yield which is about 10% of that produced by fruiting bodies.