• Title/Summary/Keyword: isolation and structure determination

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Isolation and Structure Determination of a Proteasome Inhibitory Metabolite from a Culture of Scytonema hofmanni

  • Shim, Sang-Hee;Chlipala, George;Orjala, Jimmy
    • Journal of Microbiology and Biotechnology
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    • v.18 no.10
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    • pp.1655-1658
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    • 2008

  • Cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. The ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitors can be potential anticancer agents. Cyanobacteria have been shown to be a rich source of highly effective inhibitors of proteases. A proteasome inhibitor was screened from an extract of the culture of Scytonema hofmanni on the basis of its inhibitory activity, which led to the isolation of nostodione A with an $IC_{50}$ value of 50${\mu}M$. Its structure was determined by spectroscopic methods such as $^{1}H$-NMR and ESI-MS spectral analyses.

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New Antibiotics Produced by Streptomyces melanosporofaciens II. Antimicrobial Activities and Isolation, Purification, and Structure Determination of the Active Compound (Streptomyces melanosporofaciens가 생산하는 새로운 항생물질 II. 물질의 항균활성과 황성물질의 분리.정제 및 구조결종)

  • 김시관;김상석;김근수;정영륜;김창한
    • Microbiology and Biotechnology Letters
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    • v.19 no.3
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    • pp.235-241
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    • 1991

  • - A phthalic acid derivative and basic macrolide antibiotics, with antimicrobial activity against Gram positive bacteria and phytopathogenic fungi, respectively, were found to be produced by a strain 88-GT-161 identified as being a variety of Streptomyces melanosporofaciens. This paper describes an isolation procedure of the active compounds produced by this strain, their in vitro and in vivo (pot test) antimicrobial activites, and structure determination of one of the compounds, bis (2-ethylhexyl) phthalate, a phthalic acid derivative antibiotic. This compounds, upon cornparision with authentic bis (2-ethylhexyl) phthalate, dioctyl phthalate, revealed a difference in antimicrobial activity even though physico-chemical properties of these two compounds seemed indentical. This is the first report that dioctyl phthalate is biosynthetically produced by a Streptomyces sp. and shows antimicrobial activity.

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Investigation on seismic isolation retrofit of a historical masonry structure

  • Artar, Musa;Coban, Keziban;Yurdakul, Muhammet;Can, Omer;Yilmaz, Fatih;Yildiz, Mehmet B.
    • Earthquakes and Structures
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    • v.16 no.4
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    • pp.501-512
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    • 2019

  • In this study, seismic vulnerability assessment and seismic isolation retrofit of Bayburt Yakutiye Mosque is investigated. Bayburt Yakutiye Mosque was built in the early 19th century at about 30-meter distance to Coruh river in the center of Bayburt in Turkey. The walls of historical masonry structure were built with regional white and yellow stones and the domes of the mosque was built with masonry bricks. This study is completed in four basic phases. In first phase, experimental determination of the regional white stone used in the historical structure are investigated to determine mechanical properties as modulus of elasticity, poison ratio and compression strengths etc. The required information of the other materials such as masonry brick and the regional yellow stone are obtained from literature studies. In the second phase, three dimensional finite element model (FEM) of the historical masonry structure is prepared with 4738 shell elements and 24789 solid elements in SAP2000 software. In third phase, the vulnerability assessment of the historical mosque is researched under seismic loading such as Erzincan (13 March 1992), Kocaeli (17 August 1999) and Van (23 November 2011) earthquakes. In this phase, the locations where damage can occur are determined. In the final phase, rubber base isolators for seismic isolation retrofit is used in the macro model of historical masonry mosque to prevent the damage risk. The results of all analyses are comparatively evaluated in details and presented in tables and graphs. The results show that the application of rubber base isolators can prevent to occur the destructive effect of earthquakes.

  • https://doi.org/10.12989/eas.2019.16.4.501 인용 KSCI