Composition and physical state of phospholipids in calanoid copepods from India and Norway

Abstract

The fatty acid composition and physical state of isolated phospholipids obtained from marine copepods collected on the Southwest coast of India (Calanus spp.) and the west coast of Norway (Calanus finmarchicus) were investigated to compare the adaptation of membrane lipids with seawater temperatures Phospholipid vesicles obtained from the tropic copepods proved more rigid than those from C finmarchicus, as assessed by diphenylhexatriene fluorescence polarization techniques In each case, there were two breaks present on the fluorescence polarization vs 1/T plots, suggesting that the onset and completion of phase separation to occurred above 0 C For the tropic copepods, the onset of phase separation roughly corresponded to the ambient water temperature, while for C finmarchicus some discrepancies were observed, depending on the time of the year Phospholipids in copepods from both habitats contained more than 50% unsaturated fatty acids, the animals from Norway containing slightly higher amounts The data indicate an adaptation of membranes to temperature