Streptomyces macrolidinus sp. nov., a novel soil actinobacterium with potential anticancer and antimalarial activity

A novel actinomycete, strain RY43-2 , belonging to the genus , was isolated from a peat swamp forest soil collected from Rayong Province, Thailand. The strain was characterized by using a polyphasic approach. The cell-wall peptidoglycan contained ll-diaminopimelic. Ribose and glucose were detected in its whole-cell hydrolysates. The strain contained anteiso-C , iso-C and iso-C as the predominant fatty acids, and MK-9(H ), MK-9(H ) and MK-9(H ) as the major menaquinones. The phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, three unidentified ninhydrin-positive phospholipids and two unidentified phospholipids. Strain RY43-2 showed the highest 16S rRNA gene similarity to JCM 4497 (98.9 %) and LCR6-01 (98.9 %). The draft genome of RY43-2 was 6.7 Mb with 6078 coding sequences with an average G+C content of 70.8 mol%. Genomic analysis revealed that the average nucleotide identity (ANI) values based on blast (ANIb) and MUMmer (ANIm) between strain RY43-2 and JCM 4497 were 80.1 and 86.1%, respectively. The ANIb and ANIm values between strain RY43-2 and LCR6-01 were 77.0 and 85.5%, respectively. The digital DNA-DNA hybridization values were 25.2 and 23.0% in comparison with the draft genomes of JCM 4497 and LCR6-01 , respectively. The results of taxonomic analysis suggested that strain RY43-2 represented a novel species of the genus for which the name sp. nov. is proposed. The type strain is RY43-2 (=TBRC 7286 =NBRC 115640 ). Strain RY43-2 exhibited antimicrobial activity against ATCC 51559, BMGC 106 and BMGC 107 with the minimum inhibitory concentration values of 25.0, 12.5, and 6.25 µg ml . It also exhibited potent antimalarial activity against K1 with IC of 0.0031 µg ml . In addition, it showed cytotoxicity against Vero, KB, MCF-7 and NCI-H187 with IC values of 0.0347, 6.15, 3.36 and 0.0352 µg ml , respectively.