美洲大蠊肠道链霉菌潜在新种G30的鉴定及全基因组分析OA

Objective To isolate and characterize a potential novel species of Streptomyces,designated G30,from the gut of Periplaneta americana and evaluate its secondary metabolic potential through polyphasic taxonomy and whole-genome analysis.Methods Bacterial isolation was performed using the dilution plating method.The isolated strain was subsequently identified through polyphasic taxonomy,which included 16S rRNA gene sequencing,morphological observation,and physiological and biochemical characterization.The antitumor activity of its crude extracts against MCF-7,A549,and HepG2 cells was evaluated using the CCK-8 assay.Additionally,whole-genome sequencing was carried out on the Nanopore platform,and the biosynthetic gene clusters(BGCs)were analyzed for novelty with antiSMASH 7.0.Results Strain G30 exhibited a 16S rRNA gene sequence similarity of 98.88%with the type strain Streptomyces physcomitrii LD120.However,significant differences were observed in carbon source utilization,biochemical reactions,and growth conditions,which supported its status as a potential novel species within the genus Streptomyces.The ethyl acetate crude extract of strain G30 demonstrated cytotoxic activity against MCF-7,A549,and HepG-2 cells,with the strongest inhibitory effect observed on MCF-7 cells(IC50=64.16 μg/mL).Genomic analysis identified a total of 33 BGCs.Among these,gene clusters with homology below 30%account for 30.3%of the total,and 18.2%were identified as orphan clusters,indicating a high degree of novelty.These BGCs were predicted to encode the synthesis of potentially antitumor compounds such as murayaquinone,chrysomycin,and ilamycin.Conclusion Strain G30 represents a potential novel species of Streptomyces with highly novel secondary metabolic potential,serving as an important microbial resource for the discovery of antitumor lead compounds.