Inhibitory effect of various nicotinic acid analogs on the growth of bacteria was investigated. 6-Aminonicotinamide inhibited the growth of Escherichia coli and other bacterial strains at a concentration of 5 × 10-4M. However, the growth was restored by the addition of 5 × 10-8M of nicotinamide. Instead, effect of pyridine-3-sulfoic acid was irreversible and the growth was never recovered by the addition of excess amount of nicotinamide. Mutants resistant to 6-aminonicotinamide and pyridine-3-sulfonic acid were obtained from the culture of E. coli and Achromobacter polymorph, respectively. These mutants were inclined to have a increased yield of nicotinic acid. Tracer experiments showed that intact cells of 6-aminonicotinamide-resistant strains of E. coli commonly devoided of the activity to synthesize NAD from nicotinic acid and nicotinamide. Disrupted cells also lacked the NAD synthesizing activity. However, A. polymorph and its pyridine-3-suifonic acid-resistant strains equally synthesized NAD from nicotinamide.

ニコチン酸アナログの細菌に対する生育阻害作用およびアナログ耐性株のNAD生合成の特徴について検討した. 6-アミノニコチンアミド, およびピリジン-3-スルホン酸は5 X 10-4Mの濃度で生育阻害作用を示した. 6-アミノニコチンアミドによるEscherichia coliの生育阻害は1/10 4当量のニコチンアミドの添加により回復されたのに対し, ピリジン-3-スルホン酸による阻害は過剰のニコチンアミドの添加によっても回復できなかった. 一般にE. coliの6-アミノニコチンアミド耐性株およびAchromobacter polymorphのピリジン-3-スルホン酸耐性株のニコチン酸含量は親株よりも高い傾向が認められた. またこれら耐性株はアナログの分解能は有していなかった. 6-アミノニコチンアミド耐性株E. coliではニコチンアミドおよびニコチン酸からのNAD生合成反応が認められず, 破砕菌体においても合成活性が認められなかった. ピリジン-3-スルホン酸耐性A. polymorphでは親株と同様のNAD生合成活性を示した.