Nonomuraea corallina sp. nov., isolated from coastal sediment in Samila Beach, Thailand: insights into secondary metabolite synthesis as anticancer potential

A novel marine actinomycete, designated strain MCN248T, was isolated from the coastal sediment in Songkhla Province, Thailand. Based on the 16S rRNA gene sequences, the new isolate was closely related to Nonomuraea harbinensis DSM45887T (99.2%) and Nonomuraea ferruginea DSM43553T (98.6%). Phylogenetic analyzes based on the 16S rRNA gene sequences showed that strain MCN248T was clustered with Nonomuraea harbinensis DSM45887T and Nonomuraea ferruginea DSM43553T. However, the digital DNA-DNA hybridization analyzes presented a low relatedness of 40.2% between strain MCN248T and the above closely related strains. This strain contained meso-diaminopimelic acid. The acyl type of the peptidoglycan was acetyl, and mycolic acids were absent. The major menaquinones were MK-9(H2) and MK-9(H4). The whole cell sugars consisted of madurose, ribose, mannose, and glucose. Diphosphatidylglycerol, hydroxyl-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylglycerol were detected as the major phospholipids. The predominant cellular fatty acids were iso-C16:0 (40.4%), 10-methyl-C17:0 (22.1%), and C17:1ω 8c (10.9%). The DNA G + C content of the genomic DNA was 71.7%. With in silico analyzes, the antiSMASH platform uncovered a diverse 29 secondary metabolite biosynthesis arsenal, including non-ribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) of strain MCN248T, with a high prevalence of gene cluster encoding pathways for the production of anticancer and cytotoxic compounds. Consistently, the crude extract could inhibit colorectal HCT-116 cancer cells at a final concentration of 50 μg/mL. Based on the polyphasic approach, strain MCN248 was designated as a novel species of the genus Nonomuraea, for which the name Nonomuraea corallina sp. nov. is proposed. The type strain of the type species is MCN248T (=NBRC115966T = TBRC17110T).

Nonomuraea sediminis sp. nov., a novel actinobacterium with antimicrobial activity, isolated from sediment of Dianchi Lake

A novel actinobacterium with antimicrobial activity, designated strain H16431^T, was isolated from a sediment sample collected from Dianchi Lake, Yunnan Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain H16431^T was most closely related to Nonomuraea rhizosphaerae CGMCC 4.7431^T and Nonomuraea guangzhouensis CGMCC 4.7101^T (98.1% similarity), but formed a monophyletic clade with Nonomuraea ceibae KCTC 39826^T (98.0% similarity). Phylogenomic analysis based on whole-genome sequence showed that strain H16431^T formed a separate clade within the genus Nonomuraea. The average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values between strain H16431^T and its closely related Nonomuraea species were 80.0-81.5%, 71.2-74.6%, and 23.2-25.0%, respectively, which were significantly lower than the widely accepted species-defined threshold. The DNA G + C content was 70.2% based on the whole-genome sequence. The menaquinones were identified as MK-9(H₄), MK-9(H₆), and MK-9(H₂). The major fatty acids were iso-C_16:0, 10 methyl-C_17:0, and iso-C_16:0 2OH. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, and phosphatidylinositol. These chemotaxonomic characteristics were corresponded to those of the genus Nonomuraea. On the basis of the taxonomic evidence, strain H16431^T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea sediminis sp. nov. is proposed. The type strain is H16431^T (=JCM 34852^T=CICC 25119^T).