Membrane Composition and Modifications in Response to Aromatic Hydrocarbons in Gram-Negative Bacteria

Abstract

Bacterial cells are surrounded by a cellular envelope composed of the cytoplasmic membrane and the cell wall. The cytoplasmic membrane is a phospholipid bilayer that provides an appropriate matrix for membrane proteins involved in many different cellular processes. Membrane lipid composition can change in response to different environmental challenges such as the presence of toxic compounds (e.g., aromatic hydrocarbons). The changes in membrane fluidity induced by stressors are counteracted by the bacteria through variations in the length of fatty acids, in the degree of saturation, and in the cis/trans configuration of the unsaturated fatty acids. The presence of cyclopropane fatty acids and changes in phospholipid head groups has also been shown to be involved in this stress