The unusual sensitivity of a isolate to three inhibitors of prokaryote protein synthesis [tetracycline (TET), chloramphenicol (CAM), erythromycin (ERY)] was investigated. TET inhibited growth in shake culture by 40% at 10 μg ml and 99% at 100 μg ml within 5 h (one doubling period). CAM inhibited growth by 40% at 500 μg ml and 70% at 1 mg ml. Cycloheximide (CHI), a eukaryote protein synthesis inhibitor, blocked growth completely at 1 μg ml. These agents reduced incorporation of leucine and phenylalanine into protein by 40 to 50% (100 μg TET ml, 500 μg CAM ml) or 93% (1 μg CHI ml) within 20 min. This rapid inhibitory effect could not be attributed to impaired mitochondrial energy generation. TET inhibition increased to 90% by 60 min, but CAM inhibition did not change for 5 h. TET inhibited both the transport and protein synthetic (cytoplasmic) components of amino acid incorporation, but CAM impaired only the transport activity. CHI blocked protein synthesis, but did not inhibit transport de-tectably. In contrast to these results, growth inhibition by ERY did not increase with dose (40% inhibition at 10 to 500 μg ml), and ERY at 500 μg ml inhibited neither amino acid transport nor protein synthesis in 5 h. The results indicate that the sensitivity of to these prokaryote inhibitors reflects unusual permeability properties, which account for impaired transport (CAM, TET) and allow access of the drugs to sensitive intracellular sites, the cytoplasmic (TET) and mitochondrial (ERY) protein synthetic systems.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error