Key Points ATL involves genome-wide reprogramming of the H3K27me3 pattern that is distinct from other cell types. Druggable epigenetic mechanisms are associated with ATL cell development and HTLV-1–mediated transformation.

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Valanimycin, a new azoxy antibiotic, was isolated from culture broths of a streptomycete. Valanimycin is an unstable oil at room temperature and active against some Gram-positive and Gram-negative bacteria, mouse leukemia L1210 cells in cultures, and prolongs the life span of mice inoculated with Ehrlich carcinoma or L1210.During the course of prescreening of potential antitumor antibiotics by use of a recA-deficient mutant of Escherichia coli as a test organism, an active substance isolated from culture filtrates of a streptomycete was characterized chemically and biologically. The active substance was named valanimycin on the basis of its possible biosynthesis from valine and alanine. This paper deals with isolation procedures, structure determination and biological activities of valanimycin, as well as the taxonomy of the producing organism. Materials and MethodsInstruments IR, UV and NMR spectra were recorded on Hitachi IR spectrophotometer Model 260-10, Hitachi UV spectrophotometer Model 220S, and Jeol GX400 FT-NMR spectrometer, respectively. A secondary ionization mass spectrum (SI-MS) was obtained with Hitachi M-80H mass spectrometer. TaxonomyThe taxonomy of the producing organism was performed by the method Of SHIRLING and GOTTLIEB1). Diaminopimelic acid was determined according to BECKER, et al.2). Assay of Antibiotic ActivityProduction and purification of valanimycin were followed by the antibiotic activity determination by the paper disc-agar diffusion method with Escherichia coli BE1121++ as the test organism. See the legend to Table 6 for the genetic markers. Culture ConditionsSpores from a slant culture of the producing organism were inoculated into 500-ml flasks each containing 100 ml of the culture medium which consisted of maltose 2 %, peptone 0.5 %, meat extract + Present address:

Peptide antibiotics tripropeptins A, B, C, D and Z were isolated from cultured cells and broth of Lysobacter sp. The differences among these components are in the lengths of the alkyl side chain. Tripropeptins are active against Gram-positive bacteria including MRSA in vitro. Bactericidal activity of tripropeptin C disappeared in the simultaneous presence of chloramphenicol, a bacteriostatic agent.

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