ALGAL INHIBITION BY YELLOW ULTRAVIOLET-ABSORBING SUBSTANCES FROM FUCUS VESICULOSUS

Abstract

The yellow extracellular phenolic substances produced by Fucus vesiculosus were found to be toxic to all unicellular algae examined. Concentrations which completely inhibited growth varied from approximately 25 μg/ml for Monochrysis lutheri to more than 150 μg/ml for Porphyridium sp. The toxicity appeared to result from cellular lysis rather than a deficiency of trace metals or vitamins. After fractionation on a charcoal column, only the ethanolic eluate was found to be markedly toxic. Concentrations of 100 μg/ml of the aqueous eluate caused almost no inhibition of growth of Monochrysis. The toxic factor was largely destroyed by autoclaving. It could be passed through an ultrafilter of 24A pore size, and was active both in acidic and alkaline media. It is suggested that this excretory product from Fucus may have ecological significance.