Membrane Phase Transitions in Synechococcus sp. PCC7942 Cells Can be Probed with Chlorophyll a Fluorescence

The temperatures for liquid-crystalline to phase-separated state transitions of cyanobacterial membrane lipids have been determined by several methods and were found to lie 6–11 °C higher in thylakoid membranes (TM) than in plasma membranes (PM). PM and TM transition temperatures were higher in cells cultured at a higher temperature and lower in cells cultured at a lower temperature (1). Unsaturated fatty acids are more abundant, and membranes more fluid at lower culturing temperature (2).