ANTIBACTERIAL EFFECTS 145 



good carbon sources. It is of particular interest to note that whereas 

 penicillin and flavicin are produced in media containing complex or- 

 ganic materials as sources of nitrogen, fumigacin, clavacin, and glio- 

 toxin are produced in synthetic media, the presence of complex nitrogen 

 sources often being deleterious. 



Gliotoxin was isolated from the culture filtrate by the use of lipoid 

 solvents, chloroform being most effective. Nonsterilized media ad- 

 justed to fH. 2.5 to 3.0 could be used for large-scale production, the high 

 acidity reducing the effect of contaminants (992). Gliotoxin is stable in 

 neutral and acid solutions at room temperature j at alkaline reactions, 

 it is very unstable, the rate of decomposition increasing with increasing 

 alkalinity and temperature. At ^H 2.4, heating to 122° C. for 30 min- 

 utes did not affect the active substance. With decreasing acidity, espe- 

 cially at ^H 5.0, it became less thermostable. 



Gliotoxin is also produced by a number of other fungi, including P. 

 obscurum {66$) a.nd A. fumigaius (631). 



Certain species of Trichoderma, including T. viridis, produce another 

 antibiotic substance that is particularly active against fungi, designated 

 as viridin (84). It is produced when the organism is grown in shallow 

 layers of nitrate-containing media for 4 to 6 days at 25° C. j the cultures 

 are characterized by a bright yellow color. It is isolated from the cul- 

 ture filtrate by extraction with chloroform, evaporation, and recrystalli- 

 zation from alcohol or benzene. It is stable only in acid solution. 



Fusarium Grouf 



The ability of species of Fusarium to produce antibiotic substances 

 was first observed in a survey of the antibacterial properties of fungi, as 

 pointed out above (p. 131). F. oxys forum was found (112) to pos- 

 sess antibacterial properties. One of the organisms, namely F. javanl- 

 cum', was studied in detail. A substance, designated as javanicin, was 

 isolated (26) from the medium by the use of ether or benzene. It was 

 removed from the solvent by extraction with aqueous NasCOs. It con- 

 tained a quinone group but no carboxyl. It was active against gram- 

 positive, including acid-fast, bacteria in concentrations of i : 50,000 to 

 1 : 400,000 but had little activity against gram-negative bacteria. It was 

 relatively nontoxic. 



