INFLUENCE OF MEMBRANE-COMPOSITION OF VARIOUS PARASITES ON THE INHIBITORY ACTIVITY OF A SERIES OF BIPYRIDYL ANALOGS

In a previous report the dependence of the antimycoplasmal activity of bipyridyl analogues on the presence of Cu+ ions has been shown. The i nhibitory activity of these compounds has now been studied against Esc herichia coli mycobacteria and Candida albicans in the absence and pre sence of Cu2+ ions using growth kinetic techniques. It was found that the inhibitory activity against E. coli increases in the presence of C u2+ ions. In contrast, no additional effect of Cu2+ ions is observed f or the inhibitory activity against mycobacteria. Some of the derivativ es show very promising activity even against Mycobacterium avium strai ns. More complicated is the effect of Cu2+ ions On the inhibitory acti vity of the derivatives against C. albicans. For isoquinolones the obs erved delay in onset of inhibitors is reduced and no influence on the inhibitory activity is observed. The addition of Cu2+ ions to the phen anthrolines leads in contrast to a decrease in antifungal activity. Th e possible influence of membrane properties of the studied microorgani sm on the effect of Cu2+ ions is discussed.