The Demonstration of a Nucleus in the Cell of a Staphylococcus

Abstract

In the cells of Staphylococcus flavo-cyaneus forming greenish black colonies and spontaneously dissociating into a yellow strain, the author was able to demonstrate granules which stain with methylene blue at pH 1.8-2, are insoluble in boiling water for 10 min. or in 0.02% NaHC03 for 2 hrs., give the Millon and the Sharp tests for protein and a positive Feulgen reaction. Those granules are hydrolyzed by 10% HC1 in water within 24 hrs. at room temp, and to a much less extent with the same cone, of the acid in alcohol. They are not hydrolyzed by 2% aqueous HN03 for over 12 hrs. at room temp. They recolor the Schiff reagent without partial hydrolysis, but lose this property and become Feulgen-negative when hydrolysis is complete, although they continue to give positive tests for protein. The hydrolyzed granules also do not stain with methylene blue below pH 4.6-6.8. Moreover, the granules do not give the microchem. tests for fat or glycogen, and they are not used up by starving cells, indicating that they are not reserve material. The above reactions are considered sufficient to identify the granules as consisting of nucleo-protein. The resting cell usually contains a single granule, round or slightly ellipsoidal. Actively growing cells contain 2-4 granules of shapes indicating elongation and division. It is therefore concluded that those granules are, both chemically and morphologically, of nuclear nature. The Staphylococcus is considered to be a new species and is given the name Staphylococcus flavo-cyaneus.