STRUCTURES, PROPERTIES AND RELATIONSHIP TO THE ASPERGILLOMARASMINES OF TOXINS PRODUCED BY PYRENOPHORA-TERES

The structures have been determined of toxins A, B and C, all isolated from a cell-free sterile culture filtrate of Pyrenophora teres. Toxin A was n-(2-amino-2-carboxyethyl)aspartic acid, not previously known from natural sources. Toxin C was identical with aspergillomarasmine A, and toxin B, probably in an artefact, was identical with anhydroaspergillomarasine A. Toxin A and C were toxic at a concentration of 0·25 mmol l-1, whereas toxin B was toxic only at a concentration of 1 mmol l-1. The results support a wide distribution of toxins of the aspergillomarasmine group, but since systematically closely related plants reacted differently towards the pure toxins, a high specificity must be involved in their action. © 1979.