Novel lipid components of the Azotobacter vinelandii cyst membrane.

Phospholipids are ubiquitous components of biological membranes. In the vegetative cells of Azotobacter vinelandii, a Gram-negative free-living aerobic soil bacterium, the membrane lipids are phospholipids with polar head group and fatty acyl compositions similar to those of Escherichia coli. We report here that when A. vinelandii differentiates to form metabolically dormant cysts, the phospholipids in the membranes are replaced by a family of 5-n-alkylresorcinols and 6-n-alkylpyrones. These novel amphiphilic lipids form a unique membrane matrix which may contribute to the physiology and desiccation resistance of the cyst.