Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS...Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were determined.Results:The 16 S rDNA sequencing analysis revealed that Streptomyces sp.strain MJM 10778.which was isolated from Hambak Mountain.Korea,has 99.9% similarity to Streptomyces misionensis(S.misionenis) NBRC 13063.The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC.13063.The entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging activity.The IC_(50) values of the strain MJM 10778 extract on DPPH,.NO.and ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,respectively.The ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability assay.Conclusions:The results obtained suggesl that the ethyl acetate extract of Streptomyces sp.strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.展开更多
[Objective] The paper was to screen the biocontrol agents with good control effects against tobacco bacterial wilt. [Method] The strains with antagonistic activity against tobacco bacterial wilt were isolated from 36 ...[Objective] The paper was to screen the biocontrol agents with good control effects against tobacco bacterial wilt. [Method] The strains with antagonistic activity against tobacco bacterial wilt were isolated from 36 copies of rhizosphere soil sample. The strain with best inhibition effect was identified, and carried out pot test and growth-promoting experiment. [Result] The strain with best inhibtion effect was Tra69, which was identified to be Streptomyces flavogriseus. The fermentation liquid of Tra69 had good control effect against Ralstonia solanacarum, and also had good growth-promoting effect on tobacco. [Conclusion] Tra69 was the biocontrol agent with excellent control effect against R. solanacarum, which could be further developed and used in biological control against tobacco diseases.展开更多
Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramyc...Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S. ambofaciens XC 2-37 were studied. The potency of S. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.展开更多
The usefulness of genetic/metabolic engineering for further improvement of industrial strains is subject of discussion because of the general lack of knowledge on genetic alterations introduced by iterative cycles of ...The usefulness of genetic/metabolic engineering for further improvement of industrial strains is subject of discussion because of the general lack of knowledge on genetic alterations introduced by iterative cycles of random mutagenesis in such strains.An industrial clavulanic acid(CA)-overproducer Streptomyces clavuligerus DEPA was assessed to understand proteome-wide changes that have occurred in a local industrial CA overproducer developed through succesive mutagenesis programs.The proteins that could be identified corresponded to 33 distinct ORFs for underrepresented ones and 60 ORFs for overrepresented ones.Three CA biosynthetic enzymes were overrepresented in S.clavuligerus DEPA;carboxyethylarginine synthase(Ceas2),clavaldehyde dehydrogenase(Car)and carboxyethyl-arginine betalactam-synthase(Bls2)whereas the enzymes of two other secondary metabolites were underrepresented along with two important global regulators[two-component system(TCS)response regulator(SCLAV_2102)and TetR-family transcriptional regulator(SCLAV_3146)]that might be related with CA production and/or differentiation.g-butyrolactone biosynthetic protein AvaA2 was 2.6 fold underrepresented in S.clavuligerus DEPA.The levels of two glycolytic enzymes,2,3-bisphosphoglycerate-dependent phosphoglycerate mutase and phosophoglycerate kinase were found decreased while those of dihydrolipoyl dehydrogenase(E3)and isocitrate dehydrogenase,with two isoforms were found as significantly increased.A decrease of amino acid metabolism,methionine biosynthesis in particular,as well as S-adenosylmethionine synthetase appeared as one of the prominent mechanisms of success of S.clavuligerus DEPA strain as a prolific producer of CA.The levels of two enzymes of shikimate pathway that leads to the production of aromatic amino acids and aromatic secondary metabolites were also underrepresented.Some of the overrepresented stress proteins in S.clavuligerus DEPA included polynucleotide phosphorylase/polyadenylase(PNPase),ATP-dependent DNA helicase,two isoforms of an anti-sigma factor and thioredoxin reductase.Downregulation of important proteins of cell wall synthesis and division was recorded and a protein with b-lactamase domain(SCLAV_p1007)appeared in 12 isoforms,5 of which were drastically overrepresented in DEPA strain.These results described herein provide useful information for rational engineering to improve CA production in Streptomyces clavuligerus.展开更多
基金supported by a grant from next-generation BioGreen 21 pmjcet(No.PJ009643).RDA Korea
文摘Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were determined.Results:The 16 S rDNA sequencing analysis revealed that Streptomyces sp.strain MJM 10778.which was isolated from Hambak Mountain.Korea,has 99.9% similarity to Streptomyces misionensis(S.misionenis) NBRC 13063.The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC.13063.The entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging activity.The IC_(50) values of the strain MJM 10778 extract on DPPH,.NO.and ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,respectively.The ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability assay.Conclusions:The results obtained suggesl that the ethyl acetate extract of Streptomyces sp.strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.
基金Supported by Key Science and Technology Project of Hubei Tobacco Company(027Y2012-083)
文摘[Objective] The paper was to screen the biocontrol agents with good control effects against tobacco bacterial wilt. [Method] The strains with antagonistic activity against tobacco bacterial wilt were isolated from 36 copies of rhizosphere soil sample. The strain with best inhibition effect was identified, and carried out pot test and growth-promoting experiment. [Result] The strain with best inhibtion effect was Tra69, which was identified to be Streptomyces flavogriseus. The fermentation liquid of Tra69 had good control effect against Ralstonia solanacarum, and also had good growth-promoting effect on tobacco. [Conclusion] Tra69 was the biocontrol agent with excellent control effect against R. solanacarum, which could be further developed and used in biological control against tobacco diseases.
文摘Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S. ambofaciens XC 2-37 were studied. The potency of S. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.
基金We acknowledge the Scientific and Technical Research Council of Turkey[TÜB_ITAK-KBAG,Grant No:114Z648]Middle East Technical University Research Fund[BAP-07-02-2014-007-050]for partially supporting this study.
文摘The usefulness of genetic/metabolic engineering for further improvement of industrial strains is subject of discussion because of the general lack of knowledge on genetic alterations introduced by iterative cycles of random mutagenesis in such strains.An industrial clavulanic acid(CA)-overproducer Streptomyces clavuligerus DEPA was assessed to understand proteome-wide changes that have occurred in a local industrial CA overproducer developed through succesive mutagenesis programs.The proteins that could be identified corresponded to 33 distinct ORFs for underrepresented ones and 60 ORFs for overrepresented ones.Three CA biosynthetic enzymes were overrepresented in S.clavuligerus DEPA;carboxyethylarginine synthase(Ceas2),clavaldehyde dehydrogenase(Car)and carboxyethyl-arginine betalactam-synthase(Bls2)whereas the enzymes of two other secondary metabolites were underrepresented along with two important global regulators[two-component system(TCS)response regulator(SCLAV_2102)and TetR-family transcriptional regulator(SCLAV_3146)]that might be related with CA production and/or differentiation.g-butyrolactone biosynthetic protein AvaA2 was 2.6 fold underrepresented in S.clavuligerus DEPA.The levels of two glycolytic enzymes,2,3-bisphosphoglycerate-dependent phosphoglycerate mutase and phosophoglycerate kinase were found decreased while those of dihydrolipoyl dehydrogenase(E3)and isocitrate dehydrogenase,with two isoforms were found as significantly increased.A decrease of amino acid metabolism,methionine biosynthesis in particular,as well as S-adenosylmethionine synthetase appeared as one of the prominent mechanisms of success of S.clavuligerus DEPA strain as a prolific producer of CA.The levels of two enzymes of shikimate pathway that leads to the production of aromatic amino acids and aromatic secondary metabolites were also underrepresented.Some of the overrepresented stress proteins in S.clavuligerus DEPA included polynucleotide phosphorylase/polyadenylase(PNPase),ATP-dependent DNA helicase,two isoforms of an anti-sigma factor and thioredoxin reductase.Downregulation of important proteins of cell wall synthesis and division was recorded and a protein with b-lactamase domain(SCLAV_p1007)appeared in 12 isoforms,5 of which were drastically overrepresented in DEPA strain.These results described herein provide useful information for rational engineering to improve CA production in Streptomyces clavuligerus.
