Neutralizing activity in the gastrointestinal contents of piglets vaccinated with an ethylenimine-inactivated porcine enterovirus.
(33/145)
The T80 strain of porcine enterovirus was rapidly and completely inactiviated by ethylenimine in a reaction which appeared to follow first order kinetics. The virus was effectively concentrated 35- to 88-fold, with recovery rates of 23 t0 53%, by adsorption to the polyelectrolyte PE60. Multiple doses of adjuvanted, PE60-concentrated, ethylenimine-inactivated T80 virus given by both the oral and subcutaneous routes induced the appearance of significant levels of virus neutralizing activity in the gastrointestinal tract of piglets vaccinated at four weeks of age. This activity, found predominantly in large intestine, was present 14 days after administration of the first dose of vaccine and significant levels of activity were still detectable six weeks later. Titres of serum virus neutralizing activity were higher and more persistent than in piglets which received live or formaldehyde-inactivated T80 virus by the oral or intramuscular routes. (+info)
The hydrophobic photoreagent 3-(trifluoromethyl)-3-m-([125I] iodophenyl) diazirine is a novel noncompetitive antagonist of the nicotinic acetylcholine receptor.
(34/145)
We have shown previously that the lipophilic photoreagent 3-(trifluoromethyl)3-m-([125I]iodophenyl)-diazirine ([125I]TID) photolabels all four subunits of the Torpedo nicotinic acetylcholine receptor (AChR) and that greater than 70% of this photoincorporation is inhibited by cholinergic agonists and some noncompetitive antagonists, including histrionicotoxin (HTX), but not phencyclidine (PCP; White, B.H., and Cohen, J.B. (1988) Biochemistry 27, 8741-8751). We have now examined the effects of nonradioactive TID on (a) AChR photoincorporation of [125I]TID, (b) AChR-mediated ion transport, and (c) AChR binding of several cholinergic ligands. We find that TID inhibits [125I]TID photoincorporation into the AChR to the same extent as carbamylcholine. The saturable component of [125I]TID photolabeling is half-maximal at 4 microM [125I]TID with 0.5 mol specifically incorporated per mol of AChR after 30 min photolysis with 60 microM [125I]TID. Repeated labeling of membranes at a fixed [125I]TID concentration gave results consistent with a maximal incorporation of one [125I]TID molecule per AChR. Nonradioactive TID also noncompetitively inhibits agonist-stimulated 22Na+ efflux from Torpedo vesicles with an IC50 of 1 microM. Furthermore, TID inhibits allosterically the binding of [3H]HTX, decreasing its affinity for the AChR 5-fold both in the presence and absence of agonist. In contrast, TID has little effect on [3H]PCP binding in the absence of agonist but completely inhibits it in the presence of agonist. TID enhances the cooperativity of [3H]nicotine binding. [125I]TID is thus a photoaffinity label for a novel noncompetitive antagonist binding site on the AChR that is linked allosterically to the binding sites of both agonists and other noncompetitive antagonists. The [125I]TID site is presumably located within the central pore of the AChR. (+info)
Photoaffinity labeling and fatty acid permeation in 3T3-L1 adipocytes.
(35/145)
Long chain fatty acid uptake was investigated in 3T3-L1 cells. Differentiation of these cells from fibroblasts to adipocytes was accompanied by an 8.5-fold increase in the rate of oleate uptake. This was saturable in adipocytes with apparent Kt and Vmax values of 78 nM and 16 nmol/min/mg cell protein, respectively. A number of proteins in various subcellular fractions of differentiated cells were labeled with the photoreactive fatty acid 11-m-diazirinophenoxy[11-3H]undecanoate. A 15-kDa cytoplasmic protein was induced upon differentiation to adipocytes. This protein was labeled with the photoreactive fatty acid in cytoplasm isolated from differentiated adipocytes, but not in cytoplasm from undifferentiated, fibroblastic cells. Furthermore, a high affinity fatty acid binding protein of 22 kDa was identified in plasma membranes of undifferentiated cells, and its level of labeling increased 2-fold upon differentiation. These results indicate the usefulness of the photoreactive fatty acid in identifying cellular fatty acid binding proteins, and its potential to elucidate the spatial and temporal distribution of fatty acids in intact cells. (+info)
Determination of the dissociation constants for Ca2+ and calmodulin from the plasma membrane Ca2+ pump by a lipid probe that senses membrane domain changes.
(36/145)
Synthesis and properties of diazirinyl organo-platinum compounds for manipulations of photoaffinity labeled components.
(39/145)
Synthesis of diazirinyl organo-platinum complexes, which specifically interact with purine base, characterization of photoreactivity and interaction between guanosine 5'-monophosphate (GMP) were examined. The results indicated that the diazirinyl organo-platinum complex was useful for manipulations of photoaffinity labeled components. (+info)
Fe(II)-catalyzed amination of aromatic C-H bonds via ring opening of 2H-azirines: synthesis of 2,3-disubstituted indoles.
(40/145)