Abstract
Ether and vinylether (also called plasmalogens) lipids are present in the biomembranes. In comparison with conventional glycerophospholipids they differ in the acyl chain attachment to the glycerol backbone by ether bond and plasmalogens have a cis double bond adjacent to the ether linkage. Ether lipids represent approximately 20 % of total phospholipids in mammals, with enriched amount in brain, heart, spleen, and skeletal muscle1,2. In the process of aging the content of these lipids is decreasing3. Though their influence in the process of aging is not fully understood and our aim is to investigate physico-chemical properties in membranes containing mono ether- and mono vinylether lipids.
Large unilamelar vesicles (LUVs), were used as the model membrane system, containing phospholipids with various amounts of ether and vinyl-ether lipids. We utilized GP (generalized polarization) of Laurdan measurements for temperature range (10-30°C) to determine how the fluidity of the membrane changes with temperature and whether the lipids are in gel or liquid-crystalline phase4. We performed time resolved emission spectra (TRES) for LUVs containing Laurdan for control sample (without ether lipids) and for samples with varying amount of mono-ether and mono vinylether lipids. There are two parameters we get from TRES measurements: the total amount of fluorescence shift ∆v and relaxation time τr. In the case of extreme samples (containing the biggest amount of ether or vinylether lipids) the relaxation time seems to be decreased in comparison to the control sample (POPC/POPE in the ratio 70/30). For control averaged τr=2,08 ns ±0,17 ns, for POPC/ethPE (70/30) τr = 1,25 ns, for vinethPC/POPE (70/30) is averaged τr = 0,916 ns ± 0,17 ns and for POPC/vinylethPE (70/30) τr = 2,13 ns (all were measured at 23 °C). For further investigation also with samples with lower content of ether and vinyl ether lipids more measurements are needed.