Inhibition of Growth and RNA Biosynthesis of Bacillus cereus by Quinacrine

Abstract

SUMMARYThe addition of 0.4 mmquinacrine to exponential cultures of Bacillus cereus led to the complete inhibition of growth, measured turbidimetrically. Certain metal ions such as Ca2+ and Mg2+ were partially effective in preventing growth inhibition, as was the polyamine spermine.Quinacrine inhibited most biosynthetic processes measured to the same extent as the reduction in the rate of growth. Thus the incorporation of amino acids into protein, that of diaminopimelic acid into bacterial wall, the accumulation of Kf and the uptake of nicotinic acid were diminished only in accordance with the decreased rate of turbidimetric increase. DNA biosynthesis was decreased to a lesser extent than was turbidity and continued even after growth had ceased altogether, thus indicating less inhibition of this process than that of protein formation. RNA synthesis, on the other hand, was selectively inhibited in these cells. The depressant effect was most pronounced when ribosomal or rRNA formation was examined. RNA isolated from drug-treated cells still exhibited messenger function. An additional effect of quinacrine on the uptake of certain nucleic acid bases is also postulated. The relative content of ATP in the cells was considerably increased by drug treatment.It appears that quinacrine did not exert its major action on DNA biosynthesis but selectively blocked RNA formation while that of DNA was permitted to continue.

Stimulatory Effect of Xenobiotics on Oxidative Electron Transport of Chemolithotrophic Nitrifying Bacteria Used as Biosensing Element

“…Activity of these channels may be modulated in the presence of CN which causes their opening [39], [43] and efflux of K + to the environment making the cytoplasm more negative, as compared to the environment. Such increase of the potential in the presence of cyanide was reported in other experimental systems [44], including bacterial [40], [45]. One should also note that efflux of potassium would facilitate entry cationic probe of electric potential, JC-1 (used in this study).…”

Giardiasis: clinical and therapeutic aspects.

“…Though there is no specific feature which distinguishes tropical sprue, it usually improves in response to a prolonged course of antibiotics, often with folate or vitamin B12 supplements (Guerra et al, 1965;O'Brien and England, 1971;Rickles et al, 1972). Mepacrine, a commonly used anti-giardial drug, is known to have antibacterial actions in vitro (Seligman and Mandel, 1971), but in the short courses used in the treatment of giardiasis (five to 10 days) it seems unlikely to produce the same results as prolonged antibiotic treatment in tropical sprue.…”

Bacterial target sites for biocide action

“…The attachment results from the intercalation of an acridine molecule between two layers of base pairs. Quinacrine, an antimalarial drug, blocks DNA synthesis and strongly inhibits the syntheses of RNA and proteins in E. coli (Ciak and Hahn 1967) but selectively blocks RNA formation in B. cereus (Seligman and Mandel 1971). Crystal violet has also been shown to interact with nucleic acids in E. coli (Adams 1968).…”