ANTIBACTERIAL EFFECTS 141 



tained that inhibited the growth of these bacteria in a dilution of ap- 

 proximately 1 : 200,000. 



A. flavus was found (46) to produce frequent variants j two of these 

 consistently gave far higher yields of aspergillic acid than those re- 

 ported by White. The substance was found to have wide activity, 

 especially against gram-positive cocci, but was less active against the 

 anaerobes of gas gangrene and the gram-negative bacteria. 



Bush and Goth (103) isolated from A. flavus a second substance 

 designated as flavicin. They grew the organism for 6 to 8 days on a 

 nitrate-glucose medium containing 2 per cent corn steep. The filtrate 

 was acidified to -pH 2.5 to 3.0 with phosphoric acid and extracted 

 with purified isopropyl ether. The ether was treated with a slight ex- 

 cess of o.2A^ NaHCO.j (5 to 10 cc. per liter of culture), giving a yield 

 of 75 to 100 per cent of active material obtained. Purification was ob- 

 tained by acidification of the NaHCOg extract with H3PO4 to ^H 

 2 to 3 and removal of the precipitate, the latter containing most of the 

 toxicity (due no doubt to aspergillic acid) and the filtrate most of the 

 activity. The filtrate was treated with ice-cold isopropyl ether, satu- 

 rated with COo, washed with cold distilled water, and reextracted. The 

 combined extracts were distilled at 0° C. to dryness under COo. A yel- 

 low-orange glassy residue was obtained. It had a low toxicity and was 

 active in vivo. 



The similarity to penicillin of the second antibiotic substance pro- 

 duced by A. flavus has been definitely established (605, 606) by chemi- 

 cal isolation and composition, solubility and stability, biological be- 

 havior, low toxicity to animals, and therapeutic activity. A sodium salt 

 assaying 240 O.U./mg. was obtained chromatographically and gave the 

 following composition: 45.36 per cent C, 4.16 per cent H, 3.02 per cent 

 N, and 13.36 per cent Na, [aj^ = + 108° (in water). 



Under submerged conditions, A . flavus thus produces two substances, 

 one of the aspergillic acid type and the other of the penicillin type. 

 Some strains produce little or no activity in submerged cultures, and 

 most strains produce very little activity in stationary cultures. No ac- 

 tivity is produced in synthetic media (950). The culture filtrate of A. 

 flavus grown on lactose-peptone media was active against Af . tubercu- 

 losis and other acid-fast bacteria in vitro. 



