The Gross and Biochemical Effects of 1-β-D-Arabinofuranosyl Cytosine on an Actinobolin-Resistant Strain of Streptococcus faecalis 1

Summary

The availability of a unique strain of Streptococcus faecalis, designated S. faecalis Acb-r, allowed studies which revealed the subcellular mechanism by which 1-β-D-arabinofuranosyl cytosine (ara-c) inhibits the growth of this organism. In S. faecalis Acb-r, concentrations of 1.0 × 10^-4 or 3.5 × 10^-4 M ara-c strongly inhibited the synthesis of DNA while the synthesis of RNA and protein was not greatly diminished by the same concentrations of this inhibitor. Ara-c inhibited by approximately 60–90% the incorporation of various radiolabeled nucleic acid precursors into DNA but not to any marked extent the incorporation of these precursors into RNA. Among various nucleosides and nucleotides tested, only deoxy-cytidine prevented inhibition of S. faecalis Acb-r by ara-c. These observations indicate that the primary effect of ara-c on S. faecalis Acb-r is the inhibition of DNA synthesis.