Effects of the organophosphorus plant growth regulator melaphen on structural characteristics of animal and plant membranes

Effects of low (from 4 × 10 −12 to 2 × 10 −7 M) doses of the organophosphorus plant growth regulator Melaphen on structural characteristics of plant and animal cellular membranes were compared with special reference to changes in the microviscosity of free membrane lipid bilayers and annular lipids bound to protein clusters. It was found that effective concentrations of Melaphen were not only different for animal and plant membranes, but also discrete and equal to 2 × 10 −7 or 4 × 10 −12 M depending on the membrane origin and the nature of membrane lipid components. In parallel experiments, effects of Melaphen on the rate of lipid peroxidation (LPO) in biological membranes were studied under conditions of external cold stress. The intensity of LPO was decreased at all Melaphen concentrations able to modulate the microviscosities of free and annular membrane lipids. It is concluded that effects of low and ultra-low Melaphen concentrations on structural and functional states of biological membranes of plant and animal origin are mediated by its interaction with signaling receptors of cellular membranes and cell organelles of both plant and animal origin.