[Objective] The screening method and the pathogenic function of pathogenic bacteria X46（Micromonospora）of crabgrass was studied.[Method] Improved Gaoshi No.I medium was adopted to isolate a strain of pathogenic bact...[Objective] The screening method and the pathogenic function of pathogenic bacteria X46（Micromonospora）of crabgrass was studied.[Method] Improved Gaoshi No.I medium was adopted to isolate a strain of pathogenic bacteria X46 of crabgrass from the rhizosphere soil of crabgrass and barnyardgrass,the optimal toxin production condition was determined,and the preliminary assessment of its security was conducted.[Result] Pathogenic bacteria X46（Micromonospora）of crabgrass was identified to be Micromonospora.When the liquid volume of 300 ml flask was 30 ml,initial pH was 6.0-6.5,inoculation amount was 10%,fermentation was conducted at 180 r/min,28 ℃ for 120 h,the production amount of toxin in improved Gaoshi No.I medium was the largest,these were the optimum culture condition.The bacteria had significant promotion effect on the growth of maize,tomato and soybean,which had slight inhibition effect on wheat growth and significant inhibition effect on cucumber growth.[Conclusion] X46 is a potential strain that can be developed as the biological herbicide in North China.展开更多
[Objective] The purpose of the study is to breed Micromonospora car- bonacea highly producing antibiotics and then to improve the antibiotic production. [Method] Sodium Nitrite mutagenesis, combined with rifampicin re...[Objective] The purpose of the study is to breed Micromonospora car- bonacea highly producing antibiotics and then to improve the antibiotic production. [Method] Sodium Nitrite mutagenesis, combined with rifampicin resistance screening, was used in mutation breeding of M. carbonacea highly producing antibiotics from the strain of M. carbonacea JXNU-I. [Result] The overproducing strain JXNU-1-16- Y65 was screened with the production of antibiotics 266.05% more than that of the original strain. [Conclusion] The effectiveness of sodium nitrite mutation in breeding microorganisms highly producing antibiotic was proved, and the study may lay the foundation on further development and application of the antibiotic from M. car- bonacea JXNU-1.展开更多
[Objective] In this study, the feasibility of resins to extract antibacterial substances in ferrfientation broth of Micromonospora carbonacea JXNU-1 was investigated. Various parameters including the type of resin, th...[Objective] In this study, the feasibility of resins to extract antibacterial substances in ferrfientation broth of Micromonospora carbonacea JXNU-1 was investigated. Various parameters including the type of resin, the time of adsorption and the initial pH on the extraction efficiency were investigated and optimized. [Method] The antibacterial activity of antibiotics was determined by agar diffusion method. [Result] The 717 anion resin was selected as the optimal, and its adsorption capacity reached 1 221 U/g within 2.5 h at the acidic range of pH （pH 5）. The Freundlich model was fit for the adsorption model of the 717 anion resin for antibiotics. [Conclusion] The results laid the foundation for further separating and purifying antibiotics in fermentation broth of Micromonospora carbonacea JXNU-1.展开更多
Members of the genus Micromonospora show a complex life cycle which normally involves the presence of substrate or vegetative mycelia and sporulation with single spores born on the vegetative hyphae followed by the sy...Members of the genus Micromonospora show a complex life cycle which normally involves the presence of substrate or vegetative mycelia and sporulation with single spores born on the vegetative hyphae followed by the synthesis of a dark extracellular polysaccharide. Bergey’s Manual states that micromonosporae rarely produces aerial mycelia (AM) and if so, is considered “sterile”. During the characterisation of novel micromonosporae from the Sea of Cortes, it was observed that AM is produced reproducibly in the presence of certain carbon and/or nitrogen sources. Micromanipulation of the AM subcultured onto fresh media produced colonies;hence, this structure should not be called “sterile”. TEM of the AM producing isolates suggests that the spores also show activity as reported for bacilli of marine origin. This would be the first report of the presence of “inducible” AM in micromonosporae of marine sources and that the spores of this genus have a role other than just dispersal.展开更多
To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified me...To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.展开更多
基金Supported by Funded Project in Department of Education,Hebei Province:Research on Microorganism Herbicide of Crabgrass Pathogenic bacteria(No.Z2007443)~~
文摘[Objective] The screening method and the pathogenic function of pathogenic bacteria X46（Micromonospora）of crabgrass was studied.[Method] Improved Gaoshi No.I medium was adopted to isolate a strain of pathogenic bacteria X46 of crabgrass from the rhizosphere soil of crabgrass and barnyardgrass,the optimal toxin production condition was determined,and the preliminary assessment of its security was conducted.[Result] Pathogenic bacteria X46（Micromonospora）of crabgrass was identified to be Micromonospora.When the liquid volume of 300 ml flask was 30 ml,initial pH was 6.0-6.5,inoculation amount was 10%,fermentation was conducted at 180 r/min,28 ℃ for 120 h,the production amount of toxin in improved Gaoshi No.I medium was the largest,these were the optimum culture condition.The bacteria had significant promotion effect on the growth of maize,tomato and soybean,which had slight inhibition effect on wheat growth and significant inhibition effect on cucumber growth.[Conclusion] X46 is a potential strain that can be developed as the biological herbicide in North China.
基金Supported by Science and Technology Planning Project of Jiangxi Province of China(20112BBF60026)~~
文摘[Objective] The purpose of the study is to breed Micromonospora car- bonacea highly producing antibiotics and then to improve the antibiotic production. [Method] Sodium Nitrite mutagenesis, combined with rifampicin resistance screening, was used in mutation breeding of M. carbonacea highly producing antibiotics from the strain of M. carbonacea JXNU-I. [Result] The overproducing strain JXNU-1-16- Y65 was screened with the production of antibiotics 266.05% more than that of the original strain. [Conclusion] The effectiveness of sodium nitrite mutation in breeding microorganisms highly producing antibiotic was proved, and the study may lay the foundation on further development and application of the antibiotic from M. car- bonacea JXNU-1.
基金Supported by the National Natural Science Foundation of China(31360018,31160029)the Natural Science Foundation of Jiangxi Province(20132BAB204007,20122BAB204008)+1 种基金Science and Technology Planning Project from Educational Commission of Jiangxi Province(GJJ12181)Special Fund for Agro-scientific Research in the Public Interest(201203072)~~
文摘[Objective] In this study, the feasibility of resins to extract antibacterial substances in ferrfientation broth of Micromonospora carbonacea JXNU-1 was investigated. Various parameters including the type of resin, the time of adsorption and the initial pH on the extraction efficiency were investigated and optimized. [Method] The antibacterial activity of antibiotics was determined by agar diffusion method. [Result] The 717 anion resin was selected as the optimal, and its adsorption capacity reached 1 221 U/g within 2.5 h at the acidic range of pH （pH 5）. The Freundlich model was fit for the adsorption model of the 717 anion resin for antibiotics. [Conclusion] The results laid the foundation for further separating and purifying antibiotics in fermentation broth of Micromonospora carbonacea JXNU-1.
文摘Members of the genus Micromonospora show a complex life cycle which normally involves the presence of substrate or vegetative mycelia and sporulation with single spores born on the vegetative hyphae followed by the synthesis of a dark extracellular polysaccharide. Bergey’s Manual states that micromonosporae rarely produces aerial mycelia (AM) and if so, is considered “sterile”. During the characterisation of novel micromonosporae from the Sea of Cortes, it was observed that AM is produced reproducibly in the presence of certain carbon and/or nitrogen sources. Micromanipulation of the AM subcultured onto fresh media produced colonies;hence, this structure should not be called “sterile”. TEM of the AM producing isolates suggests that the spores also show activity as reported for bacilli of marine origin. This would be the first report of the presence of “inducible” AM in micromonosporae of marine sources and that the spores of this genus have a role other than just dispersal.
文摘To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.
