The biology of ophiobolins

Ophiobolin E and 8-epi-ophiobolin J produced by Drechslera gigantea, a potential mycoherbicide of weedy grasses

“…1). Considering that the name ophiobolin E does not appear to be attributed to any compound (Au et al, 2000), we decided to assign this name to 6.…”

Phytotoxin produced by Bipolaris euphorbiae in-vitro is effective against the weed Euphorbia heterophylla

“…Similarly, the toxin from H. nodulosum was stable at pH 3 -7, but unstable within the alkaline range (Vidhyasekaran, 1977), whereas the toxin from H. sativum was more stable at the alkaline range (Das and Srivastava, 1969). Although the chemical structures of the phytotoxins produced by several species of Bipolaris are known (Au et al, 2000), that produced by B. euphorbiae Strain I has not yet been determined. Our studies, however, conclude that it's phytotoxin is unlikely to be protein by nature, as the extreme temperatures it was exposed to would lead to it's denaturation and hence, loss of biological activity.…”

“…An isolated toxin from Helminthosporium sacchari when applied to host-specific sugarcane plants, caused disease symptoms similar to those produced by the fungus (Steiner and Byther, 1971). The phytotoxins produced by Bipolaris species generally belong to a group of sesterpenoids called ophiobolins (tricyclic 5-8-5 ring systems) and have recently been reviewed by Au et al, (2000). Another related species, B. cynodontis, however, produced phytotoxins that belonged to a different group called cochlioquinones (Lim et al, 1998).…”

Ca2+–Calmodulin Feedback Mediates Sensory Adaptation and Inhibits Pheromone-Sensitive Ion Channels in the Vomeronasal Organ

“…We found that the potent CaM antagonist ophiobolin A (Fig. 5A), a membrane-permeant phytotoxin produced by pathogenic fungi (Leung et al, 1984;Peters and Mayer, 1998;O'Connor et al, 1999;Au et al, 2000), is ideal for this approach. Ophiobolin A (20 M) applied by itself had no effect on the resting conductance measured before SAG application (data not shown) or on the SAG-sensitive conductance (Fig.…”