An antibacterial agent produced by Staphylococcus epidermidis strain 5 was isolated from culture supernatants; its spectrum of activity is restricted to staphylococci and micrococci. The bacteriocin-like substance was purified to homogeneity by column chromatography on Servachrome XAD-2, CM-Sephadex C-25 and Sephadex G-50. Chemical analysis showed it to be a peptide with a molecular weight of about 6000 and an isoelectric point of about 10.5. Purified material was rapidly inactivated by trypsin, chymotrypsin and pronase and it was relatively heat-stable. After acidic hydrolysis 10 amino acid residues and two unidentified ninhydrin-positive substances were detected. Production of the bacteriocin-like substance was not inducible with mitomycin C.
Mycobacterium leprae separated from armadillo tissues stored at -80 0C is similar to that from human sources in its ability to take up 3H-labelled 3,4-dihydroxyphenylalanine (DOPA). Several inhibitors were studied which showed complete or partial inhibition of [3H]DOPA uptake. These findings suggest that M. leprae isolated from frozen tissue possesses an active uptake system for [3H]DOPA.