Heterocyst glycolipids from nitrogen-fixing cyanobacteria other than Nostocaceae

Six cyanobacteria representative of families able to form heterocysts, other than Nostocaceae, have been examined for their heterocyst glycolipids (HGs) content. While the HGs found in Nostocaceae are dominated by the presence of triols and of the corresponding C-3 ketones as aglycones, those found in the ;ther families reported here are mainly characterized by tetrols and by the corresponding ketones at the omega-3 position. The latter were found in four out of the six species examined, Scytonema hofmanni, Calothrix desertica, Chlorogloeopsis fritschii and Fischerella muscicola. Triols and the corresponding ketone glycosides were found only in a Microchaete sp. and in Tolyporhrix tenuis, the latter showing the most complex array of HGs found so far. In Calotrhix desertica and Chlorogloeopsis fritschii, a-mannosides have been found for the first time. The relevance of these data as a chemotaxonomic tool is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.