Effects of Extracts of Blue-Green Algae on Pigment Production by Serratia marcescens

Abstract

Two extract preparations from each of twelve species of blue-green algae were tested for possible anti-pigmentation activities when applied to unpigmented cultures of Serratia marcescens. Extracts from eight of these species inhibited pigment formation, two of them completely. The two extraction methods gave similar results and there appears to be no difference in the effects produced by extracts from pure and impure algal cultures. Living or preserved samples of the algae containing the anti-pigmentation factor (APF) were also toxic to mice when whole or homogenized organisms were injected intraperitoneally. Numerous tests showed that the bacterial associates of the algae did not enter into the production of the APF or the toxic substance. The most effective extract concentration was 0-2 ml. extract/ml. broth, and within the range of concentrations employed, the degree of pigment inhibition was inversely proportional to the extract concentration. The possibility of using the anti-pigmentation test to determine the presence of toxic substances in blue-green algae is suggested.