Peculiarities of fatty acid composition of the genusCaulobacter

Lipid composition and taxonomy of [Pseudomonas] echinoides: transfer to the genus Sphingomonas

Lipid components of [Pseudomonas] echinoides NCIMB 9420 have been studied as an aid to taxonomic relocation of the organism. Non-polar lipids include the carotenoid nostoxanthin and the ubiquinone Q-10. The major fatty acids are cis-vaccenic acid [18:1(11c)], hexadecanoic acid (16:0) and 2-hydroxy-tetradecanoic acid (2-OH-14:0), but 11-methyloctadec-11-enoic acid[11-Me-18:1(11)] is a significant minor component. The preponderant phospholipids are phosphatidylethanolamine and phosphatidylglycerol; minor lipids include bis(phosphatidyl)glycerol and an unidentified aminophospholipid. Several glycolipids are present, the major one being a glucuronosylceramide derived from sphinganine with amide-bound 2-OH-14:0. The lipid profile supports a proposal to reclassify the organism as Sphingomonas echinoides.

Evolutionary relationship of some stalked and budding bacteria (genera Caulobacter, "Hyphobacter", Hyphomonas and Hyphomicrobium) as studied by the new integral taxonomical method

A new approach was developed for the determination of taxonomic and evolutional relationships among four genera of oligotrophic bacteria. The main idea of this approach is the algorithmized integrative analysis of the morphological and physiological specificity of these bacteria, their 5S rRNA sequences, fatty acid and lipid composition of their membranes, as well as their sensitivity to a large variety of antibiotics. It was shown that the genera Caulobacter and Hyphomonas are closely related to each other, but they are both distant from Hyphomicrobium species. The new genus, "Hyphobacter", is placed between Caulobacter and Hyphomonas. Taxonomic heterogeneity was found to exist within the genera Caulobacter and Hyphomicrobium. Evolutional pathways from Caulobacter to Hyphomicrobium are proposed on the basis of the present data. No correlations were found between the cell morphology of the organisms and their geno- and chemotaxonomy.