Cytology of Staphylococci Before and After Treatment with Penicillin

Abstract

IN a previous communication¹, we showed that, by means of enzymes, it is possible to localize both the nucleic acids of bacteria : (1) ribonucleic acid in the cytoplasm, (2) desoxyribonucleic acid in the nucleus. Thus, we have found a method, which seems to be general, of demonstrating the nuclei of bacteria. This method has enabled us to observe the. nuclei, already known to exist, of the bacteria of the enteric and the anthracis-subtilis group and to discover the nuclei of bacillus diphtheria, gonococci and staphylococci. We have continued our investigations which enabled us to demonstrate the nuclei of meningococci, streptococci and pneumococci. In our first group, the staphylococcus was most difficult to investigate, and we were able to show its nucleus only by treatment with an alkali (lithium carbonate) previous to the action of ribonuclease ; but it was not very suitable because only isolated nuclei remained. We have overcome this difficulty by using higher concentrations of ribonuclease. It appears now that the method with ribonuclease, without previous alkaline treatment, has a quite general significance; but for each micro-organism it is necessary to study optimal conditions of ribonuclease concentration and duration of enzyme contact required to eliminate the whole content of cytoplasmic ribonucleic acid, while avoiding the non-specific lixiviation effect on the desoxyribonucleic acid of the nuclei due to long exposure to hot solutions.