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221.
Antigenic Heterogeneity of Human IgD Immunoglobulins 总被引:3,自引:0,他引:3
SUBCLASSES of the three major classes of human immunoglobulins, IgG, IgA and IgM, are recognized: four of IgG are well defined1,2 and at least two of IgA3–5 and two of IgM6,7 have been demonstrated. This communication presents evidence for the existence of an antigenic heterogeneity in the heavy chains of IgD, which may also be indicative of subclasses within this class of immunoglobulin. 相似文献
222.
Coexistence of Intraspecies and Interspecies Specific Antigenic Determinants on the Major Structural Polypeptide of Mammalian C-type Viruses 总被引:41,自引:0,他引:41
THE report of a shared viral antigen (termed gs-3) among mammalian C-type viruses from four species1, extending an earlier report of cross reactivity between mouse and cat viral antigens2, has far reaching implications in the search for human cancer viruses or their gene products. The report is confirmed both by the data presented here and also by the data obtained by another laboratory3. Our gel diffusion assays using various selected sera against mouse, hamster and cat crude and purified C-type viral antigens indicate that the cross reactive antigenic determinants are specifically present on the major structural polypeptide of C-type viruses. The polypeptide also carries species specific determinants. These conclusions are drawn from complement fixation and gel diffusion tests using six types of antisera (either individual sera or pools) prepared as described in Table 1. 相似文献
223.
Binding of Radioactively Labelled Concanavalin A and Wheat Germ Agglutinin to Normal and Virus-transformed Cells 总被引:32,自引:0,他引:32
VARIOUS substances isolated from plants cause animal cells to clump. Several of these lectins1 preferentially agglutinate cells which have been transformed spontaneously or by chemicals or viruses2–7. The best known lectins of this class are concanavalin A (Con A) isolated from jack beans8 and wheat germ agglutinin4, which seem to bind to carbohydrate groups on the cell surface. The determinants recognized by the lectins seem to be N-acetyl-D-glucosamine for WGA4 and probably α-methyl-D-glucopyranoside for Con A6. 相似文献
224.
The polytenization of rRNA cistrons in Drosophila species is studied in an attempt to follow the course of under-representation of heterochromatic compared with euchromatic chromosome regions. 相似文献
225.
Peptidyl transferase, the ribosomal enzyme which synthesizes peptide bonds, can catalyse the formation of ester linkages between α-hydroxyacyl-tRNA and aminoacyl-tRNA when ribosomes carry out a specific translation of phage R17 RNA in vitro. 相似文献
226.
Structure of the Purple Membrane 总被引:34,自引:0,他引:34
IN the preceding article1 it has been shown that a cell membrane fragment, the purple membrane, isolated from Halobacterium halobium2 contains retinal bound in a mole ratio of 1 : 1 to a protein of molecular weight 26,000 which is the only protein present. We now describe the structure of the purple membrane and its localization in the bacterial cell envelope. 相似文献
227.
228.
Virus Specific RNA in Cells transformed by RNA Tumour Viruses 总被引:21,自引:0,他引:21
Virus specific RNA comprises 5% of the nuclear RNA and 0.5–1.0% of the cytoplasmic RNA of cells transformed by murine sarcoma viruses. Even cryptically transformed cells which possess no detectable virus or viral proteins synthesize detectable amounts of viral RNA. 相似文献
229.
230.
Cell-free Studies on the Regulation of the Arabinose Operon 总被引:17,自引:0,他引:17
A DNA directed, cell-free system which synthesized L-ribulokinase coded by the L-arabinose operon ara OIBAD, has been developed. L-arabinose but not the araC gene product is required for the expression of this operon and, in addition, cyclic AMP and guanosine tetraphosphate are needed for optimal synthesis. 相似文献