Lateral domain diversity in membranes of callus and root cells of potato as revealed by EPR spectroscopy

Abstract

tected in either type of domain in the lipid ordering of the Lateral heterogeneity in terms of co-existing domains with a distinct molecular organization is an area of increasing inter-bilayer as characterized by order parameter S. However, the relative population of domains in the bilayer exhibited est in membrane biology. The structural and dynamic aspects of the in-plane domain organization of lipids are becoming stronger temperature dependence. Typically, the relative proportion of disordered domains with less molecular order well documented, especially for model membrane systems. Potato (Solanum tuberosum L. cv. Desirée) callus cells and (smaller S) was larger in the membranes of callus cells roots of plantlets from stem node culture were doped with a compared to those of root cells, indicating higher fluidity throughout the measured temperature range (5-35°C). The spin-labeled analog of the methyl ester of palmitic acid bear-Arrhenius activation energies for rearrangement of lipid ing the paramagnetic nitroxide group at position C 5 of the acyl chain, which serves as a monitor of membrane fluidity of molecules within the bilayer were found to be higher for root tissue membranes, indicating the ability of root cells to oppose the region close to the polar phospholipid head groups of the bilayer. Model reconstruction of the line-shapes of the experi-actively any drastic changes of membrane structuring under mental spectra revealed the co-existence of two types of temperature stress. The distinctions in organization of lateral membrane domains with different ordering and dynamics of domains between the callus and root cell membranes may be correlated with differences in growth rate and metabolic activ-lipids in the membranes of both callus and root cells. With changes in temperature, relatively small differences were de-ity between these two types of tissue.

An EPR study of the secretion of G‐CSF heterologous protein from Pichia pastoris

“…Our results showed that the domains described as fluiddisordered with smaller order parameters decreased their proportion of W 1 and turned into more ordered fluid domains. This observation is in accordance with our previous studies where we found that the proportions of lateral domains are sensitive parameters, by which the cells of various species respond to external stresses (Svetek et al, 1999).…”