sulfonated poly (ether ether ketone) (speek) with a low degree of sulfonation (ds = 40%) was prepared for proton exchange membrane fuel cells (pemfc). poly (ether ether ketone) (peek) was sulfonated in concentrated h2so4 under n2 atmosphere and characterized by the hydrogen nuclear magnetic resonance (h-nmr) technique. after preparation of the speek polymer, the obtained polymer was dissolved i...

Formation of pore-like structures in cell membranes could participate in exchange of matter between cell compartments and modify the lipid distribution between the leaflets of a bilayer. We present experiments on two model systems in which major lipid redistribution is attributed to few submicroscopic transient pores. The first kind of experiments consists in destabilizing the membrane of a gia...

We assessed changes in ultrastructure, membrane lipid peroxidation and antioxidant systems for cucumbner seedlings subjected to low temperature stress (day/night temperature of 8 oC /5 oC) that had been either pre-treated with 10% PEG for 2 days or not. We found extensive cell structure damage in the non-treated seedlings, whereas the seedlings pretreated with PEG to simulate drought remain...

The results of several lines of investigation indicate that membrane growth in Bacillus subtilis does not occur at one or a small number of discrete zones. No indications of large regions of membrane conservation were observed. Kinetic labeling experiments of mesosomal and plasma membrane lipids indicate that the mesosomal lipids are not precursors of the plasma membrane lipids. Density shift e...

Membrane lipid analyses and electron spin resonance (ESR) studies of membrane fluidity were carried out on the red cells of a Japanese patient with hereditary high red cell membrane phosphatidylcholine hemolytic anemia (HPCHA). Increased amounts of phosphatidylcholine (PC) and cholesterol were found in the membrane lipids of the affected patient, despite normal plasma lipids. The order paramete...

Membrane proteins interact with membrane lipids for their structural stability and proper function. However, lipid-protein interactions are poorly understood at a molecular level especially in the live cell membrane, due to current limitations in methodology. Here, we report that amphiphilic lipid probes can be used to link membrane lipids and membrane proteins in vivo. Cholesterol and a phosph...

Cell membranes are composed of a mixture of lipids. Many biological processes require the formation of spatial domains in the lipid distribution of the plasma membrane. We have developed a mathematical model that describes the dynamic spatial distribution of acidic lipids in response to the presence of GMC proteins and regulating enzymes. The model encompasses diffusion of lipids and GMC protei...