Topic summary
Tunicates
Extracted from the Wikipedia article Tunicate.
Physiology and internal anatomy
Tunicates are unusual among animals in that they produce a large fraction of their tunic and some other structures in the form of cellulose. The production in animals of cellulose is so unusual that at first some researchers denied its presence outside of plants, but the tunicates were later found to possess a functional cellulose synthesizing enzyme, encoded by a gene horizontally transferred from a Actinobacterium. When, in 1845, Carl Schmidt first announced the presence in the test of some ascidians of a substance very similar to cellulose, he called it "tunicine", but it is now recognized as cellulose rather than any alternative substance.