Metabolism of leptospires. II. The action of 8-azaguanine.

Abstract

Both the pathogen Leptospira pomona and the saprophyte L. biflexa Patoc I can convert exogenous adenine, guanine, and 8-azaguanine to the corresponding nucleotide and incorporate them into nucleic acids. L. pomona is inhibited by low concentrations of 8-azaguanine (50 μg/ml) and this inhibition is associated with less than a 5% replacement of the ribonucleic acid (RNA) guanine residues by the analogue. Guanine possessed the highest activity for antagonizing the inhibitory effect of 8-azaguanine. The biosynthetic process of L. pomona most affected by the analogue was a relative increase in RNA synthesis. The analogue-resistant L. biflexa incorporated 1/10 as much 8-azaguanine as L. pomona. The higher rate of purine biosynthesis, in addition to the lesser amount of 8-azaguanine incorporated, may account for the analogue resistance of L. biflexa.