Abstract: | The action of penicillin taken at subbacterioscopic doses on Mycobacterium rubrum cells causes changes in the size and shape of the cells, in the structure of the cell wall, in the intracellular membrane systems and in functions associated with them, and in the structure of nucleoids whose DNA packing becomes more loose. If the antibiotic is added at bacteriostatic doses, the size and shape of the cells do not change, but peptidoglycan precursors being synthesized are not incorporated into the polymer and accumulate in the periplasm. DNA overspiralization in nucleoids is a non-specific reaction, which indicates that DNA is physiologically passive. DNA is isolated with a membrane from the cytoplasm in certain cells. It is possible that the resistance of cells against penicillin is associated with the capability of DNA to become inactive in physiological terms. |