HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by SATTA, G. Articles by VARALDO, P. E. Search for Related Content PubMed Articles by SATTA, G. Articles by VARALDO, P. E. Agricola Articles by SATTA, G. Articles by VARALDO, P. E.

Micrococci Demonstrate a Phosphatase Activity Which Is Repressed by Phosphates and Which Can Be Differentiated from That of Staphylococci

¹ Institute of Microbiology, Faculty of Medicine, Catholic University of the Sacred Heart, Rome
² Institute of Microbiology, University of Siena, Siena, Italy
³ Institute of Microbiology, University of Genoa, Genoa, Italy
⁴ Institute of Microbiology, University of Ancona, Ancona, Italy

^* Corresponding author.

ABSTRACT

The phosphatase activities of 114 micrococcal strains belonging to seven different species and of an additional 150 unspeciated micrococcal strains were evaluated on solid media at various pHs containing or not containing phosphates. In the presence of phosphates, only nine strains (five unspeciated strains, one Micrococcus luteus strain, and three Micrococcus varians strains) yielded a positive reaction on plates at pH 8. In media (at pH 8) deprived of phosphates, in contrast, all but 15 strains demonstrated clear-cut phosphatase activity. Acid phosphatase could not be evaluated on solid media since none of the strains grew satisfactorily on plates at pH 5. The phosphatase activities of seven (one or two for each species, which included phosphatase-negative strains) of the strains whose colonies proved phosphatase negative at pH 8 and of 18 (two or three strains per species) of those with phosphatase-positive colonies were evaluated at pH 5 and 8.5 in toluene-treated cells which had been grown in liquid media at pH 7 containing or not containing phosphates. All strains demonstrated distinct phosphatase activity at both pHs when grown in media not containing phosphates. In contrast, when strains were grown in the presence of such substances, virtually no activity was observed at pH 8.5, and, generally, a much reduced activity was observed at pH 5. The phosphatase activity of micrococci of the various species (three to eight strains per species) was also compared with that of staphylococci of different species (5 to 10 strains per species) by the methyl green-phenolphthalein diphosphate method, the sensitivity of which can be varied by using different enzyme substrates. By using phenolphthalein diphosphate as an enzyme substrate, it was found that virtually all the different species of staphylococci yielded a positive reaction on plates not containing phosphates while almost all micrococci proved phosphatase negative with the methyl green-phenolphthalein diphosphate method. This indicates that the phosphatase activity of micrococci can easily be differentiated from that of staphylococci.