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Selective transport of Li~(+) and Na~(+) through lipid bilayers by nanhumycin

Cui Jinjuan, Tang Shubem, Shi Yuliang, Wang Wenping

Department of Physiology, Henan Medical University. Zhengzhou,Henan；China(200031)

Abstract

Nanhumycin, a new polyether antibiotic, has potent growth inhibitory effect on hay bacillus and antagonistic activity against chicken coccidiosis. Previous experiments on nerve-muscle preparations have shown that all the effects of nanhumycin on biological membrane could be correlated with its ability to act as a Na~(+) carrier. In this paper, the effets of nanhumycin on the permeability of the lipid bilayers were characterized and the main results were that Nanhumycin caused a concentration-dependent increase in membrane conductance(G_(m))of the lipid bilayers. By measuring the reversal potential in an asymmetrical solution system, it was demonstrated that the changes of G_(m) were attributed to an increase in permeability of the lipid bilayers to the lipid bilayers to cations(P_(Li)/P_(Na)=0.02), especially to Li~(+) and Na~(+). The P_(Li):P_(Na): P_(K)=4.55:1.00:0.03. These results suggests that nanhumycin is a cation carrier with high permeability for Li~(+) and Na~(+).

Key words: Nanhumycin;Lipid bilayers;Na~(+) carrier;Ion selectivity

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Citing This Article：

Cui Jinjuan, Tang Shubem, Shi Yuliang, Wang Wenping. Selective transport of Li~(+) and Na~(+) through lipid bilayers by nanhumycin. Acta Physiol Sin 1994; 46 (3): (in Chinese with English abstract).