Unsaturation of fatty acids of glycerolipids in biological membranes can be altered by changing the growth temperature of the organism. Such temperature-induced changes in unsaturation of fatty acids are explained in terms of the regulation of membrane fluidity that is necessary for the proper functioning of biological membranes. Desaturases are responsible for the regulation of levels of the fatty acid unsaturation by introducing double bonds (unsaturation bonds) into fatty acids.
In this review, we describe recent research on acyl-lipid desaturases and their importance in the tolerance and acclimation to cold of cyanobacteria. We include a discussion of the basic characteristics of fatty acid desaturation, the characterization of acyl-lipid desaturases, the genetic manipulation of desaturases in relation to modification of cold tolerance, and the temperature-regulated expression of genes for desaturases.