title: Characterization of Streptomyces MITKK-103, a newly isolated actinomycin X2-producer.
abstract: A new actinomycete strain designated MITKK-103 was isolated from the soil of a flowerpot using a humic acid agar medium. The newly isolated strain was able to produce a large amount of actinomycin X2 even under nonoptimized growing conditions and serves as a promising source of this antibiotic. Actinomycin X2 has higher cytotoxicity toward cultured human leukemia (HL-60) cells than does actinomycin D, and it induces cell death via apoptosis. A nearly complete 16S ribosomal DNA (rDNA) sequence from the isolate was determined and found to have high identity (98.5-100%) with Streptomyces galbus, Streptomyces griseofuscus, and Streptomyces padanus, indicating that MITKK-103 belongs to the genus Streptomyces. The isolate clustered with species belonging to the S. padanus clade in a 16S-rDNA-based phylogenetic tree and showed 75% overall homology to S. padanus ATCC 25646 in DNA-DNA relatedness analysis. Although the growth of the isolate was somewhat different from the three species mentioned, the strain MITKK-103 most closely resembles S. padanus on the basis of the morphological and phenotypic characteristics, phylogenetic analysis, and genotypic data. As such, this is the first report of a strain of S. padanus capable of producing actinomycins.
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kurosawa
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: V P
authors.initials: VP
authors.lastname: Bui
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: VanEssendelft
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: L B
authors.initials: LB
authors.lastname: Willis
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Lessard
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA.
authors.forename: I
authors.initials: I
authors.lastname: Ghiviriga
authors.affiliation: Biomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors.forename: T G
authors.initials: TG
authors.lastname: Sambandan
authors.affiliation: Biomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Rha
authors.affiliation: Department of Biology, Building 68-370, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. asinskey@mit.edu.|Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. asinskey@mit.edu.
authors.forename: A J
authors.initials: AJ
authors.lastname: Sinskey
mesh_terms: D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003609:Dactinomycin / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000633:toxicity; D018922:HL-60 Cells; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D010860:Pigments, Biological / Q000096:biosynthesis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012988:Soil Microbiology; D013302:Streptomyces / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D010860:Pigments, Biological; D012336:RNA, Ribosomal, 16S; D003609:Dactinomycin; C041783:actinomycin X