Climacostol, a Defense Toxin of the Heterotrich Ciliate Climacostomum virens Against Predators.

Abstract A toxic substance (climacostol) of the protozoan ciliate Climacostomum virens against the predatory ciliate Dileptus margaritifer was established as 1,3-dihydoxy-5-[(Z)-2′-nonenyl]benzene. The structure was rigorously confirmed by the total synthesis.