The carbohydrate of the cell wall of group C streptococci is one of the best known group-specific streptococcal antigens with respect to its chemical structure. In the present paper, the ultrastructural location of the carbohydrate was investigated by means of immunoelectronmicroscopic techniques. Besides group-specific antibodies, the specific binding of an agglutinin (protectin Anti-AHP) of the edible snail (Helix pomatia) to structures with terminal N-acetylgalactosamine was used to demonstrate the antigen. The agglutinin was extracted from the albumen gland of the snail and purified by column chromatography. By means of glutardialdehyde it was coupled with ferritin or horesradish peroxidase. The investigations were done on strains of Streptococcus equisimilis and Streptococcus equi. Str. pyogenes (group A streptococci) was used as a control. On whole cells of group C streptococci the carbohydrate was demonstrated on the surface of the triple-layered cell wall. Near the cross-wall the carbohydrate seems to be more concentrated. In the presence of N-acety-D-galactosamine the labelling of the cell wall was inhibited. N-acetyl-D-glucosamine did not have such an effect. On isolated cell walls, both the outer and the inner surface were tagged. This suggests that the group-specific carbohydrate covers the peptidoglycan (mucopeptide) on both sides. The cytoplasmic membrane shows no reaction.

Agglutinins↗

PubMed1975

Effects in rodents of a 1-month exposure to magnetic fields (200-1200 Gauss).

Under the conditions of the present study, magnetic fields ranging from 200 to 2000 Gauss strength have no toxic or histopathological effects on rats. The in vivo study and the histopathological results show no alterations of the vascular tissues, except for a nonpathological congestion of the spleen, and no intravascular thrombosis related to the experimental conditions. An unexpected observation was that the increase in body and organ weight of young rats was significantly greater in the groups exposed to magnetic fields. Therefore, no undesirable effects should be expected when magnetic fields within the prescribed safety limits of 200 to 2000 Gauss are applied to human subjects for several hours.

Animals↗

PubMed1975

Sindbis virus infected L cells studied by ferritin-labelled antibodies.

Sindbis virus infected L cells were examined by immunoferritin technique at different times after infection. Initially virus-specific antigens appeared diffusely distributed in the cytoplasm and at the surface of vacuoles. Later on, both labelled nucleocapsids surrounding vacuoles and mature virus within their lumen were demonstrated. Maturation of virus occurred predominantly at the periphery of cells, and that mainly by budding from cell processes. The appearance of big crystals consisting of nucleocapsids is a typical event of late stages of infection. These findings are compared with corresponding fluorescent antibody results.

Antigens, Viral↗

PubMed1975