HYDROXY FATTY ACIDS AS VALUABLE CHEMOSYSTEMATIC MARKERS IN GLIDING BACTERIA AND FLAVOBACTERIA

Abstract

The fatty acid patterns of Cytophaga-like bacteria are dominated by 2- and 3-hydroxy fatty acids with iso-branched carbon-chains. Several flavobacteria with DNA in the low GC-range have patterns nearly identical to those from cytophagas. With other flavobacteria, particularly such with DNA in the high GC-range, fatty acids with branched chains are almost completely lacking, and hydroxy fatty acids are present in small quantities only. Myxobacteria clearly form two groups with respect to their fatty acid patterns. While the representatives of the suborder Cystobacterineae (Myxococcus, Cystobacter, Stigmatella) contain substantial quantities of hydroxy fatty acids, the representatives of the suborder Sorangineae (Sorangium, Nannocystis) contain no hydroxy fatty acids at all, at least not in total cell hydrolysates. The main fatty acids of all myxobacteria have iso-branched carbon chains. As has been known for some time, the fatty acid patterns of gliding bacteria are usually dominated by compounds with (iso-) branched carbon chains /3, 9, 10, 11, 12, 13/. This is uncommon for strictly aerobic gram-negative bacteria. Recently another peculiarity of the fatty acid patterns of gliding bacteria has been discovered: i.e. that many of these organisms contain substantial amounts of hydroxy fatty acids /3/. In some cases up to 50 % of the total fatty acids were hydroxylated. While up to this time hydroxy fatty acids had only been demonstrated in lipopolysaccharide preparations from gliding bacteria /9/, they have now been found even in total cell hydrolysates, and in addition to the more common 3-hydroxy compounds, 2-hydroxy fatty acids could be identified. Branched-chain 2-hydroxy fatty acids are quite unusual and seem not to have been isolated from living organisms before. It was interesting to see, that the different groups of gliding bacteria each seem to have their own special fatty acid patterns, with the characteristic differences usually in the hydroxy acid fraction. Thus Flexibacter elegans and several other Cytophaga-like bacteria (CLB) have as the main components (besides Cig: C161 and iso Cis) 2- and 3-0H iso Cis> and 3-0H iso C17 acids, while the myxobacteria Myxococcus fulvus and Stigmatella aurantiaca yielded mainly (besides Ce: Ge: and iso Cis) iso C17 and 2-0H iso C7 acids. It thus appeared to us that the fatty acid pattern might be used in this group of bacteria as a systematic lead. We therefore analyzed more strains and species of gliding bacteria for their fatty acid patterns, and also included several flavobacteria in this study, because there may be taxonomic relations between certain flavobacteria and some of the CLB.