ABSTRACT
An acylation reaction of biological polyamines by thalidomide has been postulated to explain the teratogenic activity of this drug (Fabro et al. 1965). In a further study, thalidomide has been reported to acylate polyamines at physiological pH; the teratogenic activity of this drug appears to be linked to its high acylating power towards polyamines (Audit 1994). In the present study, the action of the thalidomide molecule and its two chemical moieties (phthalimide and glutarimide rings) on Pleurodeles embryonic development has been investigated. The phthalimide moiety, which displays acylating activity, appears to generate Pleurodeles teratogenesis. The occurrence of a correlation between acylating activity and teratogenicity was confirmed using homothalidomide and partially hydrolyzed thalidomide. The glutarimide moiety has been found to act as an enhancer of phthalimide activity and to cause moderate alterations of newt development. As the acylation of polyamines by thalidomide would deprive the embryo of these essential compounds, the effects of polyamine biosynthesis inhibitors have been compared to those of thalidomide. Both thalidomide and polyamine antimetabolites altered the early cleavage process of the Pleurodeles egg and arrested early development.
ABSTRACT
Differences in the carbohydrate composition were found in the jellies and the cortex of the unfertilized Xenopus laevis egg using lectins and blood group antibodies. Blood group H trisaccharide was detected in the outer jelly and "A-like" oligosaccharide was found in the inner jelly. The blood group A trisaccharide was detected in the vitelline envelope and the cortex. The plasma membranes were isolated and partially purified by differential centrifugation on sucrose cushion. The phospholipid composition of the membrane was assessed by quantitative two-dimensional thin layer chromatography. The major phospholipids were sphingomyelin (8%), phosphatidylcholine (55%), phosphatidylinositol and phosphatidylserine (7%), and phosphatidylethanolamine (26%). The external application of phospholipase A2 indicated a possible asymmetry of the phospholipids in the membrane such as the acidic phospholipids are preferentially located at the inner leaflet. The membrane protein and glycoprotein pattern was examined by gel electrophoresis using Triton and selective staining. Six major glycoproteins ranging from 250 to 32 kDa, were detected among the Triton-insoluble components.
