Study on the isolation,culture and antibacterial activity of actinomyces derived from Chinese herbal medicine Kirkaldyia deyrolli and whole genome sequencing of a Gordonia strain
Object To explore the diversity of symbiotic actinomycetes in the gut of the medicinal insect Kirkaldyia deyrolli,and provide new microbial resources for the development of antimicrobial drugs.Methods Isolation and purification of symbiotic actinomycetes from the gut of the Kirkaldyia deyrolli were carried out by the plate dilution method;Antibacterial activity of the strains was determined by the Oxford cup method.Classification and identification were performed by visual observation,scanning electron microscopy,and 16S rDNA sequence analysis.Strains exhibiting significant antibacterial activity were subjected to Nanopore third-generation sequencing,Genome data were annotated and analyzed by tools such as Antismash,Prism,Circos,Prodigal,eggNOG,GO,and KEGG.Results 34 strains of various actinomycetes were isolated from the gut of the Kirkaldyia deyrolli by six different culture media,including 32 strains belonging to the Streptomyces genus,1 strain to the Gordonia genus,and 1 strain to the Tsukamurella genus.Strain GHC 11 was likely a new species of Streptomyces.73.5%of the isolates were antagonistic to at least one pathogen.Strain GHC 54 exhibited significant antibacterial activity against S.aureus and MRSA.Based on morphological and molecular identification,strain GHC 54 was confirmed to belong to Gordonia terrae.The genome of strain GHC 54 had a size of 5 346 952 bp,including a circular chromosome of 5 210 251 bp and a plasmid of 136,601 bp,encoding a total of 4 828 genes with a GC content of 67.91%,which included 50 tRNA genes and 9 rRNA genes.Functional annotation of the encoded genes with eggNOG,GO,KEGG,Nr,Pfam,Swiss-prot,and TrEMBL identified a total of 4 776 annotated proteins.Strain GHC 54 contained 14 biosynthetic gene clusters,including 6 NRPS,2 Terpene,1 Ectoine,1 Arylpolyene,1 Redox-cofactor,1 NAPAA,1 Ripp-like,and 1 PKS gene clusters.The homogeneity of 85.7%of the gene clusters was less than 20%,indicating a high level of novelty.Conclusion The symbiotic actinomycetes associated with the Kirkaldyia deyrolli have good antibacterial activity,with strain GHC 54 showing potential for synthesizing novel antimicrobial compounds.This study will contribute new microbial resources for the development of antimicrobial drugs.
万方数据
维普
