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 glyco lipids (HGs) content. While the HGs found in Nostocaceae are dominated by the presence of triols and of the corresponding C-3 ketones as agl ycones, those found in the ;ther families reported here are mainly cha racterized by tetrols and by the corresponding ketones at the omega-3 position. The latter were found in four out of the six species examine d, Scytonema hofmanni, Calothrix desertica, Chlorogloeopsis fritschii and Fischerella muscicola. Triols and the corresponding ketone glycosi des were found only in a Microchaete sp. and in Tolyporhrix tenuis, th e latter showing the most complex array of HGs found so far. In Calotr hix desertica and Chlorogloeopsis fritschii, a-mannosides have been fo und for the first time. The relevance of these data as a chemotaxonomi c tool is discussed. (C) 1998 Elsevier Science Ltd. All rights reserve d.