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T Bächi

Publications and source records attributed to T Bächi.

52 records · Page 3Linked to original sources
PubMed1977

Freeze-fracture electron microscopy of human erythrocytes lacking the major membrane sialoglycoprotein.

Human erythrocytes of blood group En (a-), a rare homozygous condition involving a complete lack of the major sialoglycoprotein of the cell membrane (glycophorin A), were compared with erythrocytes from normal (En (a+)) individuals by freeze-fracture electron microscopy. No decrease in number, or variation in morphology, of the intramembranal particles of En (a-) cells was detectable. The results show that the erythrocyte sialoglycoprotein is not essential for the maintenance of the integrity of the intramembranal particles of the human erythrocyte membrane.

Erythrocyte Membrane↗
PubMed1977

Staphylococcal protein A in immunoferritin techniques.

Protein A (pA) of Staphylococcus aureus, by virtue of its reactivity with the Fc portion of a variety of mammalian immumoglobulins (IgG), can be used for electron-microscopical immunoferritin techniques. The conjugation of pA with ferritin (pA-F) by means of bis(4-fluoro-3-nitrophenyl) sulfone results in a highly specific marker for IgG in indirect labeling experiments. Native pA can be used as a noncovalent bridging agent between specific antibodies and antiferritin capturing the marker molecule. The use of pA and pA-F is demonstrated with a model system involving human erythrocytes and two rabbit antisera directed against different surface antigens of the human erythrocyte membrane.

Antibodies, Bacterial↗
PubMed1975

A simple titration assay for anti-concanavalin A sera.

A method for the titration of anti-Con A sera is described. The test is based on the fact that agglutination of Con A-coated human erythrocytes can be prevented by agitation; subsequent addition of Con A-specific antisera and IgG to Con A-coated cells leads to immediate clumping.

Antibodies↗
PubMed1975

Idiotype positive T cells visualized by autoradiography and electron microscopy.

Anti-idiotypic antibodies were prepared in (CBA X C57BL/6)F1 hybrid mice by immunization either with CBA anti-C57BL/6 alloantiserum or with purified CBA thymus-processed lymphoid cells (T cells) Iodinated anti-mouse Ig or triple sandwich ferritin-labeling techniques served to visualize the reaction between idiotype and anti-idiotype. From 5 to 10% of purified CBA T cells appeared to carry receptors for C57BL/6 antigens. Heavily labeled cells had the morphology of small lymphocytes.

Animals↗
PubMed1973

Fusion of erythrocytes by Sendai virus studied by immuno-freeze-etching.

Extensive fusion of human erythrocytes agglutinated by Sendai virus was observed after 30 s of incubation at 37 C. Electron microscopy of thin sections failed to reveal the presence of virions, viral fragments, or discrete viral antigens reactive with ferritin-labeled antibody at the sites of fusion. Immuno-freezeetching of membrane surfaces demonstrated the dispersal of viral envelope antigens from what appeared to be original sites of viral attachment. Virus-induced clustering of membrane glycoproteins was interpreted as resulting from interaction of viral antigens with membrane receptor proteins and forming the structural basis for fusion of membranes with one another.

Absorption↗
PubMed1973

Morphogenesis and ultrastructure of respiratory syncytial virus.

Respiratory syncytial (RS) virus was grown in Vero cells and fixed for electron microscopy at various stages of maturation. Both filamentous and round or kidney-shaped particles, either with (complete) or without (incomplete) internal structure, were observed. All four morphological forms were identical with respect to their reactivity with ferritin-labeled antibody to RS virus. Freezeetching revealed a structural feature apparently unique for RS virus, namely helical striations around the core on the internal aspect of the envelope. This specific configuration was already detectable during the early stages of viral differentiation of the host cell membrane. Concentration of free virus by zonal ultracentrifugation of culture fluids onto sucrose cushions yielded predominantly filamentous forms up to 10 mum in length.

Animals↗
PubMed1969

Morphogenesis of influenza A virus in Ehrlich ascites tumor cells as revealed by thin-sectioning and freeze-etching.

The budding of a tumor-adapted strain of influenza A(0) virus at the surface of Ehrlich ascites tumor cells was studied by electron microscopy. Thin sections of budding sites showed the formation of a fuzzy coat on the outside of the cell membrane and simultaneously the apposition of a dark layer on the inner side. The continuity of cellular and viral membrane seemed to be preserved up to the point where the virion remained attached by only a thin stalk. Freeze-etching of virus budding sites yielded pictures in which a clear differentiation between the viral membrane and the host cell membrane was visible. The breaks across the fuzzy coat revealed striations corresponding to the "spikes" seen in negative contrast, whereas tangentially broken virus particles were best interpreted by assuming that splitting occurred midway between the two outer layers of the envelope.

Animals↗