The Isolation,Identification And Research Of Bioactivitiy Of New Myxobacteria

Myxobacteria are Gram-negative,unicell?Lar bacteria with rod-shaped vegetative cells that exhibit gliding motility on solid surfaces and display complex group behavior and they are common dwelling in the soil.They can produce various secondary metabolites with unique structures,various species and high-effciency.They have important application values in medicine,agric?Lture and ecological environment.Myxobacteria attract more and more researchers.Using inactive bacterium Escherichia.coli-dependent or filter paper-dependent fruiting baiting techniques,we isolated 8 myxobacterial strains(S84?S85?S86?S87?S88?S89?S90?S91).Based on the phylogenetical characteristic,physiological and biochemical property and 16S rRNA gene sequence homology analysis,we identified that they belonged to the following 4 genera:5 strains belonged to Sorangium,1 belonged to Polyangium,1 belonged to Myxococcus and 1 belonged to Nannocystis.Based on the 16S rRNA gene sequence catalog data,we found that S84?S85?S86?S89 had the highest similarity to Sorangium cell?Losum strain KYC3047,the numerical value was 99%,S87 had the highest similarity to Sorangium cell?Losum strain DSM14731,the numerical value was 99%,S88 had the highest similarity to Polyangium cell?Losum strain So02007-3,the numerical value was 99%,S90 had the highest similarity to Myxococcus sp.XAC 03,the numerical value was 99%,S91 had the highest similarity to Nannocystis pusilla strain Na p29,the numerical value was 99%.This res ? Lt identified them as S84(S.cell?Losum STXZ84),S85(S.cell?Losum STXZ85),S86(S.cell?Losum STXZ86),S87(S.cell?Losum STXZ87),S88(P.cell?Losum STXZ88),S89(S.cell?Losum STXZ89),S90(Myxococcus sp.STXZ90),S91(N.pusilla STXZ91)respectively.The 8 strains showed different degrees of proliferation inhibition to various tumor cell lines by anticancer experiment in vitro,including B16,SMMC-7721,4T1,HeLa,Hep-3B and HUVEC.Based on the res ? Lts,we chosed S90 for further anticancer experiment,separation,purification and antibacterial test.We incubated fermentation supernatant of S90 with Amberlite XAD-16 adsorber resin.Then XAD-16 adsorber resin was thoroughly eluted with organic solvent methanol.We found that the methanol elution showed broad spectrum and high effect on various tumor cell lines and the IC50 to Hep-3B,Hela,SMMC-7721,B16,4T1,SW480,HUVEC were 0.328 gg/mL?0.454 ?g/mL?0.279 ?g/mL?0.453 ?g/mL?0.633?g/mL?0.926 ?g/mL?1.228 ?g/mL,respectly.The methanol elution was further purificated by RP-HPLC.And 1 single peak fragment showing strong inhibitory activity to cancer cells was obtained.LC-MS/MS identification res?Lts showed its molec?Lar size was 183.07 Da.S90 showed inhabition to different human pathoges and fish pathogens,including Enterobacter aerogenes,Salmonella typhimurium,Proteus v?Lgaris,Staphylococcus aureus,Monilia albican,Aeromonas hydrophila,Aeromonas veronii,Aeromonas caviae,Edwardsiella tarda by Plate Confrontation C?Lture Method.This work not only enriched the microbial resource for drug discovery because of having discovered new myxobacterial strains with antibacterial and tumor-toxicitivity,but also laid a foundation for further development and application of pharmaceutical leading molec?Le because of the isolating and purifying work of anti-tumor secondary products from the strain S90.