[Search for new antitumor antibiotics in the bleomycin group]

The culture of Penicillium avellaneum 444 and its bleomycin resistant variant may serve a rather valuable specific test for detecting organisms producing new antitumor antibiotics of the bleomycin group. The organisms producing antitumor antibiotics of the group of anthracyclines (rubomycin and carminomycin), actinomycins and other chemical groups do not inhibit the growth of these test-organisms. Such tests are also resistant to the effect of antibacterial antibiotics.