FIG. 2.

purH mutants require thiamine under broad conditions. (A) The effect of carbon source on the thiamine requirement of DM2 (purH355) and DM1936 (purF2085) in minimal media and adenine is shown. Cultures of DM2 were grown with glucose (□) or gluconate (⋄) as sole carbon source. Also shown is growth when gluconate medium was supplemented with thiamine (♦). Cultures of DM1936 were grown with glucose (○) or gluconate (▵) as sole carbon source. (B) The effect a purE null mutation on the thiamine requirement of a purH355 and a purF2085 mutant in glucose medium is shown. Cultures of DM929 (purF purE mutant) (▵) and DM5976 (purH purE mutant) (⋄) were grown in the absence of thiamine. Growth of DM5976 in the presence of thiamine is shown (♦). Included for comparison are the purH (□) and purF (○) mutants in glucose medium, as in panel A.