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Adobati Elena; Panza Luigi; Russo Giovanni; Colnaghi Maria I.; Canevari Silvana 《Glycobiology》1997,7(2):173-178
The murine monoclonal antibody (Mab) MBr1, raised against thebreast cancer cell line MCF7, recognizes a saccharidic epitopeoverexpressed on a high percentage of human breast, ovary, andlung carcinomas. This antigen was originally identified on theimmunogen as a globo-series glycosphingolipid with an H-likedeterminant at its terminus (globo-H). We report here the biologicalcharacterization of the entire globo-H hexasaccharide and fivesynthetic oligosaccharides representing fragments of the entirestructure andlor different anomeric configurations. Using competitivebinding assays on live cells, we identified the residues andthe linkages essential for mimicry of the cellular antigensrecognized by Mab MBr1 on the breast carcinoma cell line MCF7and small cell lung cancer cell line POVD. The terminal tetrasaccharidicfragment of globo-H is the oligosaccharide that most resemblesthe MBr1-defined epitope both on glycolipids and on glycoproteins.This information will help in the rational design of a highlyspecific reagent for active specific immunotherapy of carcinomasoverexpressing the MBr1-defined antigen. CaMBr1 immunotherapy monoclonal antibody oligosaccharides tumor-associated antigen 相似文献
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The initiation of sporangiophores of Phycomyces was analyzed under oxygen-limiting conditions. Mutants lacking -carotene have a higher oxygen threshold than the wild type depending on the residual amount of -carotene. The supersensitivity to low oxygen tension is specific for sporangiophore initiation and can be suppressed by addition of either retinal, retinol or retinol acetate to the medium. It is suggested that retinol is a natural regulator of differentiation in Phycomyces. 相似文献
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A fluorescent probe, 1-p-toluidinylnapthalene-8-sulfonate (1,8-TNS), was used to study the nonpolar sites on salmine AI. Fluorescence enhancement resulting from binding between the probe and the protein occurs at a wavelength of maximum emission of 497-500 nm, indicating the existence of moderately nonpolar binding sites on salmine AI.Fluorescence enhancement decreases as the ionic strength of the solvent is increased from 0.002 M to 0.050 M. Fluorescence increases with increasing acidity although this effect is not correlated to the pKa of 1,8-TNS. Positive cooperative binding takes place between 1,8-TNS and salmine AI. Equilibrium dialysis indicates that binding occurs only under conditions resulting in significant fluorescent enhancement. The binding was also studied using thin film dialysis, which is much faster than equilibrium dialysis and avoids the observed changes in probe-protein interaction that occur over long time periods with the latter system. 相似文献
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Starting from ancient reports that rare samples of methylene blue were apparently sufficiently contaminated with azures to give red plasmodial and red purple nuclear chromatin in Chenzinsky type methylene blue eosin stains, it was decided to determine how little azure B would suffice for such staining in methylene blue eosin stains. The traditional 1902 Giemsa had an azure : methylene blue : eosin ratio of about 6 : 3 : 6.3 : 10; Lillie's 1943 formula had a 5 : 7 : 10 ratio. In the current series of tests 5 : 7 : 10 (I), 4 : 8 : 10 (II), 3 : 9 : 10 (III), 2 : 10 : 10 (IV), 1 : 11 : 10 (V), and 0 : 12 : 10 (VI) were used. Malaria and blood stains were better than the standard 5 : 7 : 10 (I) in III, IV and II in that order. Normal and leukemic human blood, mouse blood with Plasmodium berghei, and monkey blood with the CDC strain of Pl. falciparum were used as test materials. The staining mixtures were made from highly purified samples of azure B and methylene blue. Staining mixtures contained 12 ml 0.1% thiazin dye, 10 ml 0.1% eosin, 2 ml each of glycerol, methanol and 0.1 M phosphate buffer pH 6.5, 3 ml acetone as accelerator, and distilled water to make 40 ml; staining times of 10--30 min were used. 相似文献
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S. Parodi C. Balbi M. L. Abelmoschi M. Pala P. Russo L. Santi 《Cell biochemistry and biophysics》1983,5(4):285-300
Alkaline elution is a well-known method for detecting DNA damage. Recently we have developed a viscosimetric method that is even more sensitive than alkaline elution. Here we report that the two methods, although apparently both revealing alkaline DNA fragmentation, can give dramatically different results for a significant series of compounds. We suspect that alkaline elution might reveal not only DNA fragmentation but also the extent of disentanglement of chromatin structure, whereas this DNA disentanglement rate, when evaluated viscosimetrically, is more strictly correlated with the initiation of DNA unwinding. 相似文献
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An ultrastructural and cytochemical study of normal human mammary epithelial cells cultured from post-weaning breast fluids is described. Cells were examined at the time of plating and at intervals up to 28 days in culture. Three different stages in the morphological differentiation of these cells in vitro were observed: (1) the first stage was the formation of a monolayer of single cells, which occurred between days 1 and 10 in culture. The cells in this stage were not interconnected by junctional complexes and lacked Mg++- dependent ATPase activity in the plasma membranes, but did contain a large quantity of lipid and exhibited some secretory characteristics. (2) The second stage, occurring at 10 to 16 days in culture, was characterized by the formation of junctional complexes, the appearance of Mg++-dependent ATPase in the plasma membrane and a decrease in the number of dense bodies with peroxidase activity. (3) The third stage, occurring at 16 to 28 days in culture, was characterized by the formation of stratified layers of epithelial cells, which were interconnected by a larger number of desmosomes with numerous pleomorphic microfilaments. The Mg++-dependent ATPase activity in the plasma membrane was retained and the dense bodies with peroxidase activity were rarely observed at this stage. During the last seven days were prominent in the cells of the stratified layer. After 28 days in the culture, the cells began to round up and slough off the culture plate. 相似文献
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The activation energy and the optimum pH of guanine deaminase in man, the rat, guinea pig and mouse were studied using 8-azaguanine as a substrate. The serum guanase in man and in all the animal species studied differs in activation energy from the guanase of the liver. In man, moreover, the serum guanase is also different from the brain and kidney enzyme. In the rat and guinea pig the brain enzyme has thermic activation energy different from the liver and kidney enzyme. The guanase of the serum and tissues of the guinea pig differs from the enzyme of the serum and tissues of man, rat and mouse for optimum pH. 相似文献