Mechanism of action of bilharcid and tartar-emetic

An investigation on the mechanism of action of bilharcid and tartar-emetic produced the following results. Deoxyribonucleic acid (DNA) synthesis by cell of E. coli B from either the maximum stationary phase or the exponential phase are inhibited by 3.62 mM of bilharcid or 16.81 mM of tartar-emetic immediately upon addition of the inhibitor. These drugs cause a downshift of the Tm of native DNA. They displace MG from the DNA-MG complex. They increase the specific viscosity of DNA solution. Also the synthesis of constitutive enzyme (alkaline phosphatase) was stopped, as was the induction of the synthesis of new enzyme (beta-galactosidase). Bilharcid and tartar-emetic act primarily on cell membrane and cause the release of 260 mM absorbing substances from E. coli B. Moreover, they lyse not only protoplasts of B. subtilis, but also spheroplasts of E. coli B.