Modulation of membrane fluidity by catalytic hydrogenation affects the chilling susceptibility of the blue-green alga, Anacystis nidulans

All the changes, i.e. the phase separation temperature of thylakoid lipids, shift in the chilling induced increase of K⁺ permeability and decline in photosynthetic O₂-production, respectively, brought about by temperature acclimation in Anacystis nidulans, can be accomplished by homogeneous catalytic hydrogenation of the fatty acids, as well, using a new water-soluble Pd(II) complex, hitherto unknown in biological applications. Since the thermo-adaptation replaced by proper hydrogenation conducted under isothermal condition results in a similar modification of chilling susceptibility, it afforts direct evidence that chilling response is mediated by changing the degree of fatty acid unsaturation in Anacystis nidulans.