Description:
<jats:p>Two new ether lipids, 1‐<jats:italic>O</jats:italic>‐alkyl/alkenyl‐2‐<jats:italic>O</jats:italic>‐acyl‐glycero‐3‐phosphocholine and its lyso form, 1‐<jats:italic>O</jats:italic>‐alkyl/alkenyl‐glycero‐3‐phosphocholine, were identified in the cell membrane of <jats:italic>Mycoplasma fermentans</jats:italic> using chemical analyses, GLC‐MS, MALDI‐TOF MS, and 1D and 2D NMR spectroscopy. The lipids are heterogeneous with respect to both acyl and alkyl/alkenyl residues. The acyl residues at position 2 of glycerol are hexadecanoyl and octadecanoyl in a molar ratio of 3.6 : 1 with a trace amount of octadecenoyl. The alkyl/alkenyl residues at position 1 of glycerol are hexadecyl (78%), octadecyl (7%), octadecenyl (14%), and hexadecenyl (traces). In the octadecenyl residue, the double bond has a <jats:italic>cis</jats:italic> configuration and is located at either position 1′ (plasmalogen‐type lipid) or 9′ in a ratio ≈ 1 : 1. This is the first report of the presence of alkyl and vinyl (alk‐1′‐enyl) ether lipids in the cell membrane of aerobically grown mycoplasmas. Lipids of this type have been found in some Gram‐positive bacteria, thus supporting the hypothesized close taxonomical relationship of these bacteria to mycoplasmas. The ether lipids of <jats:italic>M. fermentans</jats:italic> are structurally similar to platelet activating factor; it was demonstrated that the 2‐<jats:italic>O</jats:italic>‐acetylated lyso form lipid can mimic platelet‐activating factor activity in isolated perfused and ventilated rat lungs.</jats:p>