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Fermentation and Metabolic Pathway Optimization to De Novo Synthesize (2S)-Naringenin in Escherichia coli

  • Zhou, Shenghu;Hao, Tingting;Zhou, Jingwen
    • Journal of Microbiology and Biotechnology
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    • v.30 no.10
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    • pp.1574-1582
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    • 2020
  • Flavonoids have diverse biological functions in human health. All flavonoids contain a common 2-phenyl chromone structure (C6-C3-C6) as a scaffold. Hence, in using such a scaffold, plenty of high-value-added flavonoids can be synthesized by chemical or biological catalyzation approaches. (2S)-Naringenin is one of the most commonly used flavonoid scaffolds. However, biosynthesizing (2S)-naringenin has been restricted not only by low production but also by the expensive precursors and inducers that are used. Herein, we established an induction-free system to de novo biosynthesize (2S)-naringenin in Escherichia coli. The tyrosine synthesis pathway was enhanced by overexpressing feedback inhibition-resistant genes (aroGfbr and tyrAfbr) and knocking out a repressor gene (tyrR). After optimizing the fermentation medium and conditions, we found that glycerol, glucose, fatty acids, potassium acetate, temperature, and initial pH are important for producing (2S)-naringenin. Using the optimum fermentation medium and conditions, our best strain, Nar-17LM1, could produce 588 mg/l (2S)-naringenin from glucose in a 5-L bioreactor, the highest titer reported to date in E. coli.

FOURWING SALTBUSH AS A WINTER MAINTENANCE FORAGE FOR SHEEP IN UPLAND BALOCHISTAN

  • Rehman, Atiq-ur;Rafique, Shahid;Aro, Richard S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.3 no.2
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    • pp.85-89
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    • 1990
  • Sixteen Harnai lambs were used in a completely randomized design to study the nutritive value of fourwing saltbush as a winter maintenance browse in comparison to native range grazing with or without protein and energy supplementation at Tomagh Range Livestock Research Station, in Loralai District, Balochistan. The animals were divided into four groups of four lambs each. These four groups were assigned four treatments at random: fourwing saltbush grazing alone, range grazing plus lucerne hay (100 g/head/day), range grazing plus barley grain (100 g/head/day) and range grazing alone for ten weeks. The results indicate that the two range grazing plus supplementation treatments produced weight gains which were not significantly different from each other (p < 0.05). Both of these treatments yielded significantly higher weight gains (p < 0.05) than did range grazing alone except for the last week of the study. Fourwing saltbush grazing provided cumulative weight gains at 3, 4, 6, 7 and 8 weeks which were not significantly different from the range grazing plus lucerne hay treatment and gained an average of 6 percent in body weight over the 10 week period of study. The carrying capacity for sheep of a mature stand of fourwing saltbush was approximately 20 Sheep-kg-days (SKD) of grazing per cubic meter of foliage. Results of this study suggest that under fourwing saltbush grazing alone, lambs do not only maintain their body weights but can also gain weight in winter.

The Investigation on Color Change of Dis-azo Acid Dye in Wool Dyeing (양모섬유의 염색시 디스아조계 산성염료의 변색현상 규명)

  • 김미경;김태경;윤석한;임용진
    • Textile Coloration and Finishing
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    • v.15 no.2
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    • pp.86-92
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    • 2003
  • It is already known that the color of wool fabric dyed with disazo acid dyes could be changed in dyeing process and this is accelerated under alkaline condition. Focus was given to figuring out the mechanism of this color change, through the LC-MS analysis. In this study, no color change was seen in wool fabrics dyed with C. I. Acid Blue 113 under weak acidic, neutral and weak alkaline conditions for 1hour. However, the wool fabrics dyed under weak alkaline condition for a long time over 3 hours fumed reddish orange. When the wool fabrics dyed under weak acidic, neutral and weak alkaline conditions were treated with $0.5g/L\;Na_2C0_3$ solution, all of them turned reddish orange. On the other hand, the color of silk fabrics dyed with C. I. Acid Blue 113 were not changed after the same alkaline treatment. Wool contains cystine and cysteine, whereas silk does not. Due to the reversible reduction/oxidation process of cystine and cysteine in wool dyeing, the C. I. Acid Blue 113 of the dis-azo type is decomposed by reduction and consequently turned them into the reddish orange mono-azo types dye.

Development of Rainfall - Delayed Response Model for the Calculation of Baseflow Proportion (기저유출량추정을 위한 강우 지연반응모형 개발)

  • 홍종운;최예환
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.30 no.2
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    • pp.31-43
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    • 1988
  • The Purpose of this study is to develop the rainfall-delayed response model (RDR Model) which influences the baseflow proportion of rivers as a result of the antecedent precipitation of the previous several months. The assesment of accurate baseflows in the rivers is one of the most important elements for the planning of seasonal water supply for agriculture, water resources development, hydrological studies for the availability of water and design criteria for various irrigation facilities. The Palukan river gauging site which is located in the Pulukan catchment on Bali Island, Indonesia was selected to develop this model. The basic data which has been used comprises the available historic flow records at 19 hydrologic gauging stations and 77 rainfall stations on Bali Island in the study. The methology adopted for the derivation of the RDR model was the water balance equation which is commonly used for any natural catcbment ie.P=R+(catchment losses) -R+(ET+DP+DSM+DGW). The catchment losses consist of evapotranspiration, deep percolation. change in soil moisture, and change in groundwater storage. The catchment areal rainfall has been generated by applying the combination method of Thiessen polygon and Isohyetal lines in the studies. The results obtained from the studies may be summarized as follows ; 1. The rainfall-runoff relationship derived from the water balance equation is as shown below, assuming a relationship of the form Y=AX+B. Finally these two equations for the annual runoff were derived ; ARO$_1$=0.855 ARF-821, ARF>=l,400mm ARO$_2$=0.290ARF- 33, ARF<1,400mm 2. It was found that the correction of observed precipitation by a combination of Thiessen polygons and Isohyetal lines gave good correlation. 3. Analysis of historic flow data and rainfall, shows that surface runoff and base flow are 52 % and 48% (equivalent to 59.4 mm) of the annual runoff, respectively. 4. Among the eight trial RDR models run, Model C provided the correlation with historic flow data. The number of months over which baseflow is distributed and the relative proportions of rainfall contributing in each month, were estimated by performing several trial runs using data for the Pulukan catchment These resulted in a value for N of 4 months with contributing proportions of 0.45, 0.50, 0.03 and 0.02. Thus the baseflow in any month is given by : P$_1$(n) =0.45 P(n) +0.50 P(n-I ) +0.03 P(n-$_2$) +0.02 P(n-$_3$) 5. The RDR model test gave estimated flows within +3.4 % and -1.0 % of the observed flows. 6. In the case of 3 consecutive no rain months, it was verified that 2.8 % of the dependable annual flow will be carried over the following year and 5.8 % of the potential annual baseflow will be transfered to the next year as a result of the rainfall-delayed response. The results of evaluating the pefformance of the RDR Model was generally satisfactory.

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Roundtable Discussion at the UICC World Cancer Congress: Looking Toward the Realization of Universal Health Coverage for Cancer in Asia

  • Akaza, Hideyuki;Kawahara, Norie;Nozaki, Shinjiro;Sonoda, Shigeto;Fukuda, Takashi;Cazap, Eduardo;Trimble, Edward L.;Roh, Jae Kyung;Hao, Xishan
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.1
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    • pp.1-8
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    • 2015
  • The Japan National Committee for the Union for International Cancer Control (UICC) and UICC-Asia Regional Office (ARO) organized a Roundtable Discussion as part of the official program of the UICC World Cancer Congress 2014 in Melbourne, Australia. The theme for the Roundtable Discussion was "Looking Toward the Realization of Universal Health Care 'UHC' for Cancer in Asia" and it was held on December 5, 2014. The meeting was held based on the recognition that although each country may take a different path towards the realization of UHC, one point that is common to all is that cancer is projected to be the most difficult disease to address under the goals of UHC and that there is, therefore, an urgent and pressing need to come to a common understanding and awareness with regard to UHC concepts that are a priority component of a post-MDG development agenda. The presenters and participants addressed the issue of UHC for cancer in Asia from their various perspectives in academia and international organizations. Discussions covered the challenges to UHC in Asia, collaborative approaches by international organizations, the need for uniform and relevant data, ways to create an Asia Cancer Barometer that could be applied to all countries in Asia. The session concluded with the recognition that research on UHC in Asia should continue to be used as a tool for cancer cooperation in Asia and that the achievement of UHC would require research and input not only from the medical community, but from a broad sector of society in a multidisciplinary approach. Discussions on this issue will continue towards the Asia-Pacific Cancer Conference in Indonesia in August 2015.

Development of L-Threonine Producing Recombinant Escherichia coli using Metabolic Control Analysis (대사 조절 분석 기법을 이용한 L-Threonine 생산 재조합 대장균 개발)

  • Choi, Jong-Il;Park, Young-Hoon;Yang, Young-Lyeol
    • KSBB Journal
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    • v.22 no.1
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    • pp.62-65
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    • 2007
  • New strain development strategy using kinetic models and metabolic control analysis was investigated. In this study, previously reported mathematical models describing the enzyme kinetics of intracellular threonine synthesis were modified for mutant threonine producer Escherichia coli TF5015. Using the modified models, metabolic control analysis was carried out to identify the rate limiting step by evaluating the flux control coefficient on the overall threonine synthesis flux exerted by individual enzymatic reactions. The result suggested the production of threonine could be enhanced most efficiently by increasing aspartate semialdehyde dehydrogenase (asd) activity of this strain. Amplification of asd gene in recombinant strain TF5015 (pCL-$P_{aroF}$-asd) increased the threonine production up to 23%, which is much higher than 14% obtained by amplifying aspartate kinse (thrA), other gene in threonine biosynthesis pathway.

Testing of Common Electromagnetic Environments for Risk of Interference with Cardiac Pacemaker Function

  • Tiikkaja, Maria;Aro, Aapo L.;Alanko, Tommi;Lindholm, Harri;Sistonen, Heli;Hartikainen, Juha E.K.;Toivonen, Lauri;Juutilainen, Jukka;Hietanen, Maila
    • Safety and Health at Work
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    • v.4 no.3
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    • pp.156-159
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    • 2013
  • Background: Cardiac pacemakers are known to be susceptible to strong electromagnetic fields (EMFs). This in vivo study investigated occurrence of electromagnetic interference with pacemakers caused by common environmental sources of EMFs. Methods: Eleven volunteers with a pacemaker were exposed to EMFs produced by two mobile phone base stations, an electrically powered commuter train, and an overhead high voltage transmission lines. All the pacemakers were programmed in normal clinically selected settings with bipolar sensing and pacing configurations. Results: None of the pacemakers experienced interference in any of these exposure situations. However, often it is not clear whether or not strong EMFs exist in various work environments, and hence an individual risk assessment is needed. Conclusions: Modern pacemakers are well shielded against external EMFs, and workers with a pacemaker can most often return to their previous work after having a pacemaker implanted. However, an appropriate risk assessment is still necessary after the implantation of a pacemaker, a change of its generator, or major modification of its programming settings.