ABSTRACT
A study was made of the inductive-resonance energy transfer between chromophore pairs, tryptophan--pyren, tryptophan--1.8-anilinonaphthalene sulfonate (ANS), puren--1.8-ANS, diphenylhexatrien--ethidium, and 1,8-ANS--ethidium, in irradiated (250 Gy) and nonirradiated preparations of erythrocytic membranes. The radiation--induced decrease in the energy transfer was noted in the pairs in which one of the chromophores was localized in a lipid phase. On the basis of the data obtained it is suggested that irradiation of membranes causes the lesions in them which lead to a reduction of the effective thickness of a hydrophobic part of the lipid bilayer.
Subject(s)
Erythrocyte Membrane/radiation effects , Anilino Naphthalenesulfonates/radiation effects , Animals , Cobalt Radioisotopes , Diphenylhexatriene/radiation effects , Energy Transfer/radiation effects , Ethidium/radiation effects , Gamma Rays , In Vitro Techniques , Pyrenes/radiation effects , Rats , Tryptophan/radiation effectsABSTRACT
Low doses of radiation reduce the rate and magnitude of fluorescent probe interaction with spleen cells. The uptake of 8-anilino-naphthalene sulfonic acid (ANS), but not diphenyl-hexatriene (DPH), is reduced in a dose-dependent fashion in cells that receive 25-100 rads. The effects of irradiation are most evident in a "medium" fluorescent subpopulation with no effect observed for a "dim" subpopulation. Splenic lymphocytes enriched for T cells show lower uptake of ANS, compared with a B-cell-enriched population. In addition, the normal decrease in ANS fluorescence polarization that occurs during the initial 10 minutes of probe interaction is attenuated in irradiated cells. These findings are consistent with the notion that low doses of radiation limit the penetration of ANS, but not DPH, into a less restrictive microenvironment within the plasma membranes of T, but not B, cells.