Studies on a new antibiotic XXXX produced by Micromonospora. III. Biological activities.

@entity9463 @entity137 @entity19 @entity71237 @entity794 @entity71238 @entity14284 @entity8270
The six major components of @entity71237 , a new antibiotic complex produced by Micromonospora verruculosa MCRL 0404 showed a similar type of antimicrobial spectrum. Among these components, VA-2 exhibited the most potent antimicrobial activity, particularly significantly against some Gram-positive bacteria and Neisseria. VA-2 and @entity14284 also exhibited marked inhibitory effects against L-forms of @entity794 209P and @entity9463 . The MICs of VA-2, @entity71238 and @entity14284 were remarkably affected by the pH of the test medium, the inoculum size and the amount of horse serum added in the medium. By intraperitoneal administration, these components showed good protective effects in @entity19 infected intraperitoneally with @entity794 Smith. However, the protective effect decreased remarkably by other administration routes. In addition, components such as VA-2 and @entity14284 exhibited @entity137 against HeLa S-3 cells in vitro and excellent in vivo antitumor activity against @entity8270 . VA-2 possessed a high order of acute @entity137 to @entity19 [LD50:1.9 mg/kg (i.p.); 1.8 mg/kg (i.v.)], but others were relatively less toxic.
