Accumulation of 5(4)-Amino-4(5)-Imidazolecarboxamide Riboside by Bacillus pumilus

Abstract

Nonexacting purineless mutants were isolated from an inosine-forming adenine auxo-troph of Bacillus pumilus. Some of them accumulated Bratton-Marshall reaction-positive material in their culture fluid. The product was isolated in crystalline form and identified with 5(4)-amino-4(5)-imidazolecarboxamide riboside (AICA-Riboside).
AICA-Riboside accumulated by the nonexacting purineless mutants was less than inosine accumulated by their parent adenine auxotroph.
A number of mutants that require adenine specifically were isolated from AICA-Riboside-forming purineless mutants. More than half of them accumulated a large amount of AICA-Riboside as compared with their parents, nonexacting purine auxotrophs. The rest of adenine-requiring mutants from purineless mutants lost the ability to accumu-late AICA-Riboside.
The effect of hypoxanthine on the accumulation of ACIA-Riboside by these auxotrophs was also examined.