Table 4. Sulfanilamide, Sulfathiazole, and Sulfapyridine as Inhibitory Analogues of 

 p-Aminobenzoic Acid 



Other organisms for which the toxicity of sulfonamides in vitro is prevented by p-aminobenzoic acid 

 include: Bacillus subtilis; 1 * 2 Brucella paramelitensis; im Eberthella typhosa; nl Proteus friedlanderi; 110 Pseu- 

 domonas pyocyanea; li2 Salmonella paratyphi; 111 Salmonella schottmuelleri;'" Shigella dysenteria; m Botrytis allii 

 Munn; ul Fusarium caeruleum (Lib.) Sacc.; 141 Penicillium diaitatum Sae<\;'» t'hlordla (pigmented and non- 

 pigmented) 143, l44 ; Nitzschia polea var. debilis (fresh water diatom) 145, 146 ' » 7 ; Flax seed; 148 Onion rootlets; 149 

 Pea roots 160 ' 151 and shoots. 151 



Ratio of the activity of the sulfonamide to sulfanilamide. 100 



b For half-maximum growth. 



e Molecular equivalents of sulfonamide neutralized by one molecular equivalent of p-aminobenzoic acid. 



d In the absence of purines. 



• Varies with different strains. 

 / AtpH 7.1, 2000 at pH 3.7. 



9 Either p-aminobenzoicless strains 1663 or 5359 or parent strain. 



* Inhibition index depends on strain. Mitis, intermedia*, and gravis strains are susceptible. 



