Free sterols of the historically important green algal genera, Acetabularia and Acicularia (Polyphysaceae): a modern interpretation

Abstract

Ecology and Evolution Group, Department of Biology, P.O. Box 60, Middle Tennessee State University, Murfreesboro, TN 37132 USA With 1 figure and 1 table Abstract: The genus Acetabularia represents a group of historically important, macroscopic, single-celled green algae initially used by Joachim Hammerling to demonstrate localization of genetic material within the nucleus of a cell (by grafting one species onto another and allowing it to regenerate its original form). Acetabularia, and the related genus Acicularia, are considered to be “living fossils” within the family Polyphysaceae because of their long and uninterrupted fossil record, and, as such, are important taxa in the evolutionary progression of green algae (and plants). To date, there is just a single published study on the sterols of Acetabularia mediterranea. Sterols, tetracyclic lipids which act to reinforce eukaryotic plasma membranes, are often used as chemotaxonomic indicators to assess relationships between eukaryotes. Examination of sterols within Acetabularia and Acicularia may help further identify an ancestral set of sterols that has since radiated throughout many green algae. Two C28 and three C29 sterols commonly found in green algae, all with Δ5 unsaturations and with the dominant one being 24-ethylcholest-5-en-3β-ol, were observed in four species of Acetabularia and one of Acicularia. The chemotaxonomic and evolutionary aspects of this finding are discussed herein.