High Quality Content by WIKIPEDIA articles! Yessotoxins (YTXs) are a group of lipophilic sulphated polyester) compounds that are structurally related to brevetoxins and ciguatoxins. They are produced by a number of planktonic algal species particularly the dinoflagellates, Lingulodinium polyedrum, Gonylaulax spiniferia and Protoceratium reticulatum.