C. A. Wood

Immunochemical studies of conjugates of isomaltosyl oligosaccharides to lipid: Specificities and reactivities of the antibodies formed in rabbits to stearyl-isomaltosyl oligosaccharides

Abstract The specificities and the sizes and shapes of the antibody combining sites of the 15 antisera raised against various stearyl-isomaltosyl oligosaccharides were studied by quantitative precipitin and precipitin inhibition. The antibodies precipitated well with dextrans B512 and B1424 but less well with B1299S and B1355S. Only 3 of the 15 antisera reacted with linear dextrans; however, with about 50% of the added antibodies being precipitated, showing that most of the antibodies cannot bind to internal determinants along the dextran molecules and are similar to myeloma protein W3129 in having cavity-type sites which bind only to terminal nonreducing ends of α1 → 6 dextran. Antibodies differing in the sizes of their antibody combining sites were elicited in different rabbits by the same antigen. Of the 15 antisera studied, four have antibody combining sites as large as IM3, five as large as IM4, three as large as IM5 and three as large as IM6. The association constants for various isomaltose oligosaccharides of an antiserum (R-862) showing fewest bands in isoelectric focusing gel were determined by affinity electrophoresis and were comparable to W3129.

Immunochemical studies of conjugates of isomaltosyl oligosaccharides to lipid: Fractionation of rabbit antibodies to stearyl-isomaltosyl oligosaccharides and a study of their combining sites by a competitive binding assay☆

Abstract An antiserum to stearyl-IM5 liposomes, R-856, with a high proportion of IgM and IgG antibodies was separated into IgM and IgG fractions by column chromatography. The IgM and IgG antibody binding sites were studied by quantitative precipitin, precipitin inhibition and competitive binding assays. Both were similar to unfractionated antibodies with sites complementary to IM4. Another antiserum, R-846, was separated into antibody fractions of restricted heterogeneity by preparative isoelectric focusing and their combining sites were studied by competitive binding. Two groups of site sizes were found, one complementary to IM5 was similar to the unfractionated antiserum whereas the other had smaller size sites complementary to IM4.

Origin of Olympus Mons Escarpment by erosion of pre-volcano substrate

OF all the large shield volcanoes of Mars, Olympus Mons is unique in being fringed by a nearly continuous scarp rising 1–4 km above the surrounding terrain1,2 (Fig. 1). We present evidence that the scarp was caused by preferential erosion of fragmental cratered terrain material previously adjacent to, and at present underlying the shield volcano. Removal of this material caused undercutting and collapse of the shield flanks, producing the observed terraces and scarps.