Study on secondary metabolites and antibacterial activity of Streptomyces sp. KC17012
Streptomyces belongs to the Gram positive bacteria, prokaryotes, Actinobacterales, Streptomyces family, and Streptomyces genus. Streptomyces is an important microbial resource that mainly exists in ecosystems such as soil, ocean, and freshwater. It is widely used in drug research, agricultural insecticides, herbicides, and other fields. Streptomyces have a magical creative ability to produce a large number of structurally novel and biologically active secondary metabolites, most of which are nitrogen-containing compounds. According to statistics, secondary metabolites produced by Streptomyces account for about 2/3 of the total microbial active products discovered so far. The antibiotics used in medical applications are mostly metabolites of Streptomyces, such as aminoglycoside antibiotics, which play a crucial role in medical and agricultural production. In recent years, with the increasing maturity of research on ordinary environmental microorganisms, special environmental microorganisms, such as extreme environments such as oceans, volcanic vents, and polar regions, have become a hot research topic. Li et al. isolated compounds with anti Vibrio parahaemolyticus from marine Streptomyces HS-34. Ye et al. isolated two strains of Streptomyces from mangrove soil in Guangxi and found that the secondary metabolites of both strains had good inhibitory effects on Staphylococcus aureus; Zhou et al. discovered cyclic dipeptides with tumor cytotoxic activity from the secondary metabolites of the polar fungus Geomycespannorum SA3-2-YM. Streptomyces KC17012 was isolated by our research group from the soil of Dongchuan copper mine. Based on the morphology and characteristics of the strain, combined with systematic evolutionary analysis of the 16SrRNA gene, it was determined to be a new strain (GenBank number: MW526995). Therefore, our research group continues to study Streptomyces spp KC 17012 is undergoing in-depth research with the aim of elucidating its secondary metabolites and laying the foundation for its further development.

 

Streptomyces have magical creative functions, and their secondary metabolites often have significant physiological activities. This article isolated the fermentation broth of Streptomyces KC17012 from Dongchuan copper mine and obtained 18 components, mainly including dipeptides, indole alkaloid derivatives, abscisic acid analogues, etc. Compounds 1 and 10 were tested for in vitro antibacterial activity, with MIC values of 11 and 33 μ mol/L, respectively. The remaining compounds showed no activity. Compounds 1-4 are dipeptide components with high content, while compound 3 is composed of D-type proline and L-type tyrosine, which are rare in nature as peptide substances involving D-type amino acids. Compounds 11-14 are components of abscisic acid (ABA) analogues. ABA is an important plant hormone that plays a crucial role in regulating plant growth and resisting extreme external environments. However, the production cost of ABA is high and difficult to industrialize on a large scale, so utilizing microbial metabolism to produce ABA has broad application space. This article studies the antibacterial activity of secondary metabolites and monomer components in the fermentation broth of Streptomyces KC17012, providing scientific reference for further exploration of other antibacterial activities and mechanisms of this compound.