THE METABOLISM OF PURINES IN AEROBACTER AEROGENES: A STUDY OF PURINELESS MUTANTS

Abstract

Two purineless mutants of Aerobacter aerogenes, strain 1033, were isolated. Strain P-14 is a guanlneless mutant which will grow only on guanine, guanosine, guanylic acid, or 2,6-diaminopurine. Strain PD-1 is nonexacting in its purine requirement and grew on all the purlnes, ribosides, and ribotides used in this work with the exception of 2,6-diaminopurlne, xanthosine, and xanthylic acid. It also grew on 4-amino-5-lmidazole carboxamide. Although it will not grow on 2,6-diaminopurine alone, this compound spares guanine or adenine when either of the latter compounds is present in the culture medium. In order to obtain maximum growth of strain PD-1 thlamin was required. Strain P-14 accumulates xanthosine in culture fluids, and its growth on guanine, guanosine, guanylic acid, or 2,6-diaminopurlne is inhibited by adenine or hypoxanthine and to a lesser extent by adenosine. It is not inhibited, at the levels tested, by either adenosine-3[image]-phosphate or adenosine-5[image]-phosphate. On the basis of these results the genetic blocks in both these mutants are postulated, and the pathway of purine synthesis in A. aerogenes is tentatively suggested.