“…This substance (for the chemistry see section 3, Tables 1 and 3) was found in the eggs of rainbow trout [740], and the egg jelly coat from the amphibians Pleurodeles waltlii [48], Axolotl mexicanum [105], and Xenopus laeuis [741]. In trout, it is part of gangliosides [ 1221 and glycoproteins, where it can terminate long sialic acid chains or form poly-Kdn chains [267].…”