1980 Volume 33 Issue 2 Pages 199-204
New antibiotics, macbecins I and II, have been found in the culture fluid of an actinomycete, which has the following properties: delayed fragmentation of vegetative mycelia, formation of coremia on solid media, the occurrence of meso-diaminopimelic acid in the cell wall, lysozyme resistance, and guanine-cytosine content of 71±1 mol%. The organism has been designated Nocardia sp. No. C-14919 (N-2001). A marked enhancement of the production of macbecins I and II was observed in cultures containing L-tyrosine. The antibiotics are moderately active against several Gram-positive bacteria and fungi. The antibiotics also inhibit the growth of Tetrahymena pyriformis W at 2μg/ml but show no activity against the regeneration of cilia in partially deciliated Tetrahymena at 10μg/ml.