Non-detergent Isolation of Membrane Structures from Beet Plasmalemma and Tonoplast Having Lipid Composition Characteristic of Rafts

Role of Plasmalemma Microdomains (Rafts) in Protection of the Plant Cell Under Osmotic Stress

“…In our investigations, some growth of USFAs was noted in the mass of FAs of the plasmalemma membrane fraction of zone 1 under osmotic stress. Meanwhile, the mass of SFAs in the check samples exceeded the mass of USFAs, and the marked growth of the mass of USFAs, obviously, did not play any role in the adaptation mechanisms, especially because about 5% of all the lipids introduced into the sucrose density gradient were present in zone 1 (Ozolina et al 2020b). The variations in the content of sterols, sterol esters, and SFAs may probably lead not only to some change in the membrane's biophysical characteristics.…”

“…In our experiments, the lipids in zone 4 under hyperosmotic stress (and, probably, likewise under salt stress) demonstrate credible growth of the content of SFAs (Table 5). Zone 4 contains most of the lipids (about 70% of all the lipids) added to the sucrose density gradient for separation at high-speed centrifugation (Ozolina et al 2020b). In our investigations, some growth of USFAs was noted in the mass of FAs of the plasmalemma membrane fraction of zone 1 under osmotic stress.…”

“…2.3, were frozen and, next, thawed, shaken at the range of 1,200-1,400 rpm in a shaker MS1 Minishaker (IKA Werke, Germany) at 4 ºC during 30 min in the buffer (20 mM Tris-HCl, 1 mM MgCl 2 , 1 mM CaCl 2 , 300 mM sucrose, 0.2 mM aminoethyl-benzenesulfonyl fluoride, 1 mg/ml aprotinin, 10 µM bestatin, 3 µM E-64, 10 mg/ml leupeptin, 2 µM pepstatin, pH 7.8) and were placed in the sucrose density gradient of 15-25-35-45-60%. The vesicles were centrifuged at 200,000 g during 18 h. After the centrifugation, the gradient appeared to be subdivided into the zones [Table 2, for details see (Ozolina et al 2020b)]. Zone 1 (15% sucrose) and zone 4 (35% sucrose) were analyzed for quantitative and qualitative composition of lipids (by TLC), sterols, and fatty acids (by GC-MS).…”

Eukaryotic Cell Membranes: Structure, Composition, Research Methods and Computational Modelling

“…While macroscopic domains are relatively well understood, the study of micro- and nanoclusters (or domains) that form a snapshot of the apportionment of dynamic, structural, electrical, hydrophobic, etc., properties at the membrane-water interface is of increasing interest. Many studies have proven that such nanodomains are very important for the proper functioning of cell membranes [ 9 , 43 , 53 , 88 , 91 , 92 ].…”

“…In 1997, Simons and Ikonen [ 41 ] suggested a concept of a ‘lipid raft’ to explain the lateral irregularity of the membrane; a lipid raft was described as a small (10–200 nm), heterogeneous, hugely dynamic region abundant in sterols, glyco- and phospho-sphingolipids and phospholipids (PhL) with saturated fatty acids (FA) [ 42 ]. Lipid rafts are characterised as microdomains of the lipid bilayer of the cell membrane, where areas with a higher packing density of lipid molecules are formed around particular proteins [ 43 , 44 ]. The functions of the cytoskeleton and glycocalyx have been subsequently outlined in the more complex membrane models [ 18 ].…”