Worcester Foundation for Biomedical Research

About: Worcester Foundation for Biomedical Research is a based out in . It is known for research contribution in the topics: Estrone & Estrogen. The organization has 2195 authors who have published 2646 publications receiving 115809 citations. The organization is also known as: Worcester Foundation for Experimental Biology.

Biochemistry of ATP-dependent red cell membrane shape change

Abstract: Red cell membranes prepared by hemolysis and washing in hypotonic Tris buffer crenate when suspended at 0 degrees C in isotonic medium. At 37 degrees C, in the presence of 1 mM MgATP, the crenated membranes are progressively converted to smooth-contoured discs and cup-forms. The phosphorylation of proteins and lipids during shape transformation in the presence of [gamma-32P]ATP has been studied. Spectrin phosphorylation and shape change could be dissociated in several ways, demonstrating that spectrin phosphorylation is neither necessary nor sufficient for the membrane smoothing reaction. Adenosine markedly inhibited phosphoinositide regeneration without altering shape change. Phosphatidic acid synthesis from endogenous diacylglycerol was not affected by adenosine and comparison of sheep, human and rabbit ghosts, which vary greatly in shape change capacity, demonstrated a direct correlation between phosphatidic acid synthesis and shape change rate. The results suggest that membrane curvature may be induced by diacyglycerol phosphorylation at the inner surface of the membrane bilayer, while the membrane skeleton limits the curvature and determines the shape ultimately assumed.

Deposition of cholesterol in experimental rabbit atherosclerosis.

Abstract: SummaryCholesterol-C14 and cholesterol-H3 were fed to rabbits for 1 week and cholesterol was isolated from aortae, livers, small intestines, adrenals, kidneys, brains and blood. Isolated material from all tissues had a lower count than the material fed. It was surprising that cholesterol-H3 counts were always comparatively lower than cholesterol-C14 counts. This discrepancy may be explained by a peripheral oxidation of the cholesterol-H3 molecule, in which it loses radioactive hydrogen and therefore radioactivity. This peripheral oxidation is apparently mainly operative in blood. If after feeding of radioactive material non-radioactive cholesterol is fed for 7 or 11 weeks, radioactivity in both types of experiments is reduced to a small fraction of original values. From these data one can calculate that about 0.03 mg cholesterol are laid down in the aorta/animal/day/g of wet tissue, a very small part of the 900 mg fed/day/animal. The experiments show that there is a continuous exchange of radioactive chol...