Ultrastructural demonstration of a glycoproteinic surface coat in allergenic pollen grains by combined cetylpyridinium chloride precipitation and silver proteinate staining

Summary In allergenic birch pollen grains, highly watersoluble surface substances were precipitated by the cationic detergent cetylpyridinium chloride (CPC) during aqueous fixation. After processing the pollen for electron microscopy, ultrathin sections of pollen grains were subjected to the periodic acid — thiocarbohydrazide — silver proteinate (PA-TCH-SP) procedure according to Thiery (1967) for the detection of vicinal glycol groups. It was found that the material precipitated by CPC on the surface and within the exine cavities of the pollen wall strongly reacted with the PA-TCH-SP reagent thus indicating the presence of polysaccharides on the surface of birch pollen grains. In samples which had not been treated with the cationic detergent, PA-TCH-SP reactivity was reduced to thin linings on the surface and within the exine cavities. In both cases the exine proper did not stain whereas the intine showed moderate staining. Within the aperture region of the intine, PA-TCH-SP reactivity is preferably associated with fibrillar or reticular structures. The results are discussed with special reference to biochemical findings on allergenic birch pollen proteins.     

Immunoelectron-microscopic localization of diffusible birch-pollen antigens in ultrathin sections using the protein-A/gold technique

Pollen grains from Betula pendula were fixed in a mixture of p-formaldehyde and cetylpyridinium chloride (CPC) for the precipitation of soluble pollen glycoproteins. After dehydration and embedding at low temperatures in the water-soluble resin, Lowicryl K4M, ultrathin sections of the pollen grains were incubated using specific antibodies against birch-pollen extract and protein-A/gold complexes. Antigen activity was found in the CPC-precipitated surface material and within the exine (bacular cavities) and the cytoplasm (except for starch grains and lipidic droplets). There was no labelling within the intine. The region of the germinal aperture also showed a very low degree of antigen activity. The control sections were almost completely free of background staining.     

Effect of 6-aminonicotinamide in teratogenic doses on the DNA- and RNA-concentration in rabbit embryos.

Pregnant rabbits were injected ip with 5 mg/kg 6-ANA at day 10, 11, 12 or 12.5 respectively of gestation. Embryos removed at day 13 of gestation had reduced DNA and RNA concentrations. The differences (DNA: 14 percent; RNA: 22.4 percent) were significant in the group treated on the twelfth day. Some possible mechanisms are discussed.     

Immunoelectron-microscopic localization of diffusible Birch-pollen antigens in ultrathin sections using the protein-A/gold technique

Summary Pollen grains from Betula pendula were fixed in a mixture of p-formaldehyde and cetylpyridinium chloride (CPC) for the precipitation of soluble pollen glycoproteins. After dehydration and embedding at low temperatures in the water-soluble resin, Lowicryl K4M, ultrathin sections of the pollen grains were incubated using specific antibodies against birch-pollen extract and protein-A/gold complexes. Antigen activity was found in the CPC-precipitated surface material and within the exine (bacular cavities) and the cytoplasm (except for starch grains and lipidic droplets). There was no labelling within the intine. The region of the germinal aperture also showed a very low degree of antigen activity. The control sections were almost completely free of background staining.     

Effect of products from heated amino acids on conductance in lipid bilayer membranes and non-aqueous solvents

The electrical conductance of lipid bilayer membranes of oxidized cholesterol is elevated 10²–10³ times by the addition of various products of the heating of amino acids. Solution of such products in chloroform yields a greater increase in conductance. The results are obtained with both water-soluble and water-insoluble fractions. They are discussed in the context of the origin of electroconductive tissue.     

Beitrag zur Kenntnis der Vogelfauna des Graslandes von Neukamerun

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