High levels of ergonovine and lysergic acid amide in toxic Achnatherum inebrians accompany infection by an Acremonium-like endophytic fungus

Achnatherum inebrians (drunken horse grass) causes symptoms in sheep and horses reminiscent of ergot alkaloid intoxication. Microscopical examination of seed and leaf tissues revealed the presence of an endophytic fungus that did not produce spores when grown in culture and which was serologically related to endophytic Acremonium species of the Albo-lanosa section Morgan-Jones & Gams. ELISA indicated the presence of high concentrations of ergot alkaloids. Ergonovine and lysergic acid amide were identified by HPLC-at levels up to 2500 and 400 mg kg(-1), respectively-as the major ergot alkaloids by their retention times and their UV and fluorescence scans. Their identities were confirmed by HPLC analysis of epimerized extracts, and the identity of ergonovine was further confirmed by high-resolution FAB-MS and HPLC-FAB-MS. These are the highest levels of ergonovine and lysergic acid amide so far reported in an endophyte-infected grass, and the similarity of many of the symptoms of A. inebrians intoxication to those previously reported for ergonovine and lysergic acid amide implicates these alkaloids as causative agents of the toxicosis. Endophyte-free A. inebrians did not contain detectable levels of ergot alkaloids and may therefore be useful for stock fodder. A. inebrians was also examined for the presence of other alkaloids that are commonly found in endophyte-grass associations. N-Acetylloline and N-formylloline were not detected by GC, and peramine was not detected by HPLC, in endophyte-infected A. inebrians. However, ELISA and HPLC analyses were consistent with the presence of low levels of analogues of the indole-diterpenoids paxilline and lolitrem B.