Studies on the Protein Biosynthesis in Mycobacteria
(III) Influence of Various Antibiotics on the Protein Biosynthesis in Mycobacteria
1964 Volume 19 Issue 11 Pages 437-442
Details
1964 Volume 19 Issue 11 Pages 437-442
In previous papers, it was demonstrated that ribosome fractions were obtained from the cell-free extracts of Mycobacterium 607 (M. 607) and BCG by means of preparative ultracentrifugation.
This report deals with influence of antibiotics on the14C-amino acids incorporation into the protein fraction by the ribosome systems prepared from M. 607 and BCG.
M. 607 and BCG were cultured with a tween 80 synthetic medium. The cells were harvested at an exponential phase, and washed with and resuspended in the 0, 01 M of tris buffer containing 0, 01 M of MgCl2. The cell-free extracts of the washed cells were prepared by passing through the French pressure cell at 400 kg/cm2 followed by centrifugation at 5, 000 g for 20 minutes. The ribosome fractions were isolated from the cell-free extracts by ultracentrifugation at 105, 000 g for 120 minutes after removal of fractions which were precipitated at 20, 000 g for 60 minutes.
Studies were carried out on influence of antibiotics on the14C-amino acids incorporation into the protein fractions by these ribosome systems and cell-free systems.
Results obtained were as follows:
1) The cell-free extract prepared from M. 607 was capable of incorporate 14C-amino acids into its, protein fraction in the presence of ATP and its generator. This 14C-amino acids incorporation was inhibited by the addition of 50 μg/ml of chloramphenicol (CM) and tetracycline (TC).
2) Furthermore, the 14C-amino acids incorporation into the protein fractions by the ribosome fractions prepared from M. 607 and BCG were inhibited by the addition of 50 μg/ml of CM, TC, erythromycin (EM) and streptmycin (SM), but not inhibited by isoniazid.
3) When the ribosomes isolated from normal cells of M. 607 were incubated with 100 μg/ml of EM and TC at 37°C for 2 hours, analytical centrifugation patterns revealed disappearance of 94, 1 S particles and dissociation of 74, 4 S particles into 45, 6 S and 30, 2 S particles.
From these results, the mode of action of TC, EM and SM, and Selective toxicitiesof them were discussed.
