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.

Purification of Actinomycin D from Streptomyces parvulus Isolated from Mangrove Ecosystem of Kerala, India

“…The characterization data support the fact that the compound belongs to actinomycin D (Fig 3).Mass spectral data were compatible with actinomycin D, as recorded by Lackner et al, (2000).Around 19 species ofStreptomyces (Kurosawa et al, 2006;Praveen, 2008), Micromonospora (Wagman, 1976) and Nocardia (El-Refai, 2011)reported are capable of producing various forms of actinomycins. …”

Production of actinomycin-D by a new isolate,Streptomyces sindenensis

“…Production of actinomycin-D is reported by various species of Streptomyces and Micromonospora (Wagman et al, 1976;Kurosawa et al, 2006). (Sousa et al, 2002).…”

Production of actinomycin-D by the mutant of a new isolate of Streptomyces sindenensis

“…Among the actinomycins, actinomycin-D (act-D) has been studied extensively and is used clinically for the treatment of Wilms' tumor (3). Various strains of Streptomyces and Micromonospora are reported to produce different forms of actinomycins (9). Production and optimization of act-D by S. sindenensis is not reported in literature.…”