지질의 첨가를 통한 포도당 기반 무세포 단백질 합성 시스템의 단백질 발현 효율 향상

이소정,김호철,김동명 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.7

Cell-free protein synthesis utilizes the translational machinery in a cell extract. Unlike the conventional cell-based expression methods, not being affected by the conditions for cell growth, cell-free protein synthesis enables flexible manipulation of individual factors affecting the efficiency protein biosynthesis. However, the high cost and low stability of the energy sources to regenerate ATP have limited the use of cell-free synthesis for large-scale production of recombinant proteins. One of the approaches to address this problem is to use glucose as an alternative energy source to regenerate ATP through the glucose-metabolizing pathways in a cell extract. In this study, in an attempt to improve the efficiency of ATP regeneration by reinforcing oxidative phosphorylation process, we supplemented with cellular lipids to a glucose-fueled reaction mixture for cell-free protein synthesis. As a result of the lipid supplementation, the productivity of chloramphenicol acetyltransferase in a cell-free synthesis system using glucose increased more than 6 fold compared to when the lipid was not supplemented. 무세포 단백질 합성 시스템은 세포를 파쇄한 후 파쇄액 내의 단백질 합성기구들을 이용하여 단백질을 발현하는 시스템으로 기존의 세포 기반 재조합 단백질 발현 기법들과 달리 세포의 생장조건에 영향을 받지 않으면서 발현 조절에관한 다양한 인자들을 인위적으로 조절 할 수 있는 장점이 있다. 그러나, 단백질 합성 과정 중 소모되는 ATP의 연속적 재생을 위해 사용되는 에너지원의 높은 비용과 낮은 안정성은 재조합 단백질 대량생산에의 적용을 제약하는 요인으로 작용하여 왔다. 이러한 문제를 해결하기 위한 대안들 중의 하나로 포도당을 에너지원으로 사용하여 세포 파쇄액내 대사과정을 통해 ATP를 재생하는 방법이 있다. 본 연구에서는 포도당을 에너지원으로 이용한 무세포 합성 시스템에서의 단백질 합성 효율 향상을 위하여 대장균 파쇄액으로부터 회수된 지질을 추가적으로 첨가함으로써 산화적 인산화 과정에서의 ATP재생을 증진시키고자 하였다. 그 결과, 지질이 추가된 무세포 단백질 합성 시스템은 지질이 추가되지 않은 대조군에 비하여 6배 이상 향상된 단백질 생산성을 나타내었다.

지질의 첨가를 통한 포도당 기반 무세포 단백질 합성 시스템의 단백질 발현 효율 향상

이소정 ( So Jeong Lee ),김호철 ( Ho-cheol Kim ),김동명 ( Dong-myung Kim ) 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.1

무세포 단백질 합성 시스템은 세포를 파쇄한 후 파쇄액 내의 단백질 합성기구들을 이용하여 단백질을 발현하는 시스템으로 기존의 세포 기반 재조합 단백질 발현 기법들과 달리 세포의 생장조건에 영향을 받지 않으면서 발현 조절에 관한 다양한 인자들을 인위적으로 조절 할 수 있는 장점이 있다. 그러나, 단백질 합성 과정 중 소모되는 ATP의 연속적 재생을 위해 사용되는 에너지원의 높은 비용과 낮은 안정성은 재조합 단백질 대량생산에의 적용을 제약하는 요인으로 작용하여 왔다. 이러한 문제를 해결하기 위한 대안들 중의 하나로 포도당을 에너지원으로 사용하여 세포 파쇄액내 대사과정을 통해 ATP를 재생하는 방법이 있다. 본 연구에서는 포도당을 에너지원으로 이용한 무세포 합성 시스템에서의 단백질 합성 효율 향상을 위하여 대장균 파쇄액으로부터 회수된 지질을 추가적으로 첨가함으로써 산화적 인산화 과정에서의 ATP재생을 증진시키고자 하였다. 그 결과, 지질이 추가된 무세포 단백질 합성 시스템은 지질이 추가되지 않은 대조군에 비하여 6배 이상 향상된 단백질 생산성을 나타내었다. Cell-free protein synthesis utilizes the translational machinery in a cell extract. Unlike the conventional cell-based expression methods, not being affected by the conditions for cell growth, cell-free protein synthesis enables flexible manipulation of individual factors affecting the efficiency protein biosynthesis. However, the high cost and low stability of the energy sources to regenerate ATP have limited the use of cell-free synthesis for large-scale production of recombinant proteins. One of the approaches to address this problem is to use glucose as an alternative energy source to regenerate ATP through the glucose-metabolizing pathways in a cell extract. In this study, in an attempt to improve the efficiency of ATP regeneration by reinforcing oxidative phosphorylation process, we supplemented with cellular lipids to a glucose-fueled reaction mixture for cell-free protein synthesis. As a result of the lipid supplementation, the productivity of chloramphenicol acetyltransferase in a cell-free synthesis system using glucose increased more than 6 fold compared to when the lipid was not supplemented.

A Power Control Scheme of a Fuel Cell Hybrid Power Source

Yujin Song(송유진),S. B. Han(한수빈),S. I. Park(박석인),H. G. Jeong(정학근),B. M. Jung(정봉만),G. D. Kim(김규덕),S. W. Yu(유승원) 한국조명·전기설비학회 2008 한국조명·전기설비학회 학술대회논문집 Vol.2008 No.10월

This paper describes a power control scheme to improve the performance of a fuel cell-battery hybrid power source for residential application. The proposed power control scheme includes a power control strategy to control the power flow of the fuel cell hybrid power system and a digital control technique for a front-end dc-dc converter of the fuel cell. The power control strategy enables the fuel cell to operate within the high efficiency region defined by the polarization curve and efficiency curve of the fuel cell. A dual boost converter with digital control is applied as a front-end ed-ed converter to control the fuel cell output power. The digital control technique of the converter employs a moving-average digital filter into its voltage feedback loop to cancel the low frequency harmonic current drawn from the fuel cell and then limits the fuel cell output current to a current limit using a predictive current limiter to keep the fuel cell operation within the high efficiency region as well as to minimize the fuel cell oxygen starvation.

Multi-cube UV source 이용한 PDP에서 광학시뮬레이션의 정확성 개선에 관한 연구

강정원,엄철환,Kang, Jung-Won,Eom, Chul-Whan 한국반도체디스플레이기술학회 2007 반도체디스플레이기술학회지 Vol.6 No.2

Optical simulation of the rear and front panel geometries were needed to improve the luminance and efficiency in PDP cells. The 3-dimensional optical code can be used to analyze the variation of geometries and changing of optical properties. In order to improve the accuracy of simulated results, a new UV source, called a multi-cubes UV source, was designed. To design the source, at first UV distribution was calculated with the plasma fluid code and then the UV distribution was transformed to the multi-cube structures in the optical code. Compared to the results from existing UV source, called a planar UV source, could be improved the accuracy of visible light distribution. Simulated results were also compared to the visible distribution measured with the ICCD in a real PDP cell.

Comprehensive Control Strategy and Verification for PEM Fuel Cell/Battery/Supercapacitor Hybrid Power Source

Hoai-An Trinh,Hoai Vu Anh Truong,Minh-Duc Pham,Tri Cuong Do,Hong-Hee Lee,Kyoung Kwan Ahn 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2

Using renewable energy is becoming a new tendency for vehicular applications to reduce fossil fuel consumption and minimize greenhouse gas emissions. Well-known as an eco-friendly energy source, the proton exchange membrane fuel cell (PEMFC) is extensively used in hybrid power systems to achieve the objective of zero-emission and air protection. However, this type of fuel cell offers slow dynamics and cannot adapt to abrupt load variations when used as a primary energy source. To overcome this shortcoming, battery (BAT) and/or supercapacitor (SC) are supplemented as auxiliary sources. In this paper, an innovative energy management strategy (EMS) for a PEMFC/BAT/SC hybrid power source (HPS) is proposed to improve the accuracy of power distribution from energy sources to the load. In detail, according to different characteristics of energy sources, a frequency decoupling (FD) method is designed to determine the required currents for PEMFC, BAT, and SC based on the load power demand. Besides, an adaptive DC bus control loop is utilized to guarantee a stable DC output voltage by using the BAT. The proposed EMS is simulated in a MATLAB/Simulink environment and experimentally implemented with a real-time DSP TMS320F28379D controller board. Subsequently, a test bench of a 200 W PEMFC, 24 V–12 Ah battery, and 25 V–60 F supercapacitor is conducted for experimental validation. The obtained results show that the proposed EMS is effective to coordinate energy flows between the three used sources and enhance the fuel cell performance in a hybrid power system.

플라스크 배양에서 Chlorella sp. KR-1의 균체 성장 및 지질 생산에 대한 질소원 및 유기탄소원의 영향

이자연,서경애,오유관,Lee, Ja-Youn,Seo, Kyoung Ae,Oh, You-Kwan 한국해양바이오학회 2014 한국해양바이오학회지 Vol.6 No.2

Recently microalgae have been proposed as a promising biodiesel feedstock, owing to their higher lipid productivity and non-arable land based cultivation system. Biomass and lipid productivities of microalgae are largely affected by various environmental and nutritional factors. In this study, the effects of nitrogen (nitrate and ammonium) and organic carbon (glucose and glycerol) sources on the cell growth and lipid production of Chlorella sp. KR-1 were examined in flask cultures. Under autotrophic culture conditions for 15 days, overall cell growth and lipid (fatty acid methyl ester, FAME) production with nitrate were better than those of ammonium, resulting in 1.06 g cell/L and 333 mg FAME/L, respectively. Maximal intracellular lipid contents (348 - 352 mg FAME/g cell) were observed at low concentrations of 1 mM for both nitrate and ammonium. In the supply of light, addition of glucose in the range of 1 - 20 g/L showed higher cell densities than the autotrophic cell growth condition. Higher lipid accumulation of 375 mg FAME/g cell could achieved at 5 g glucose/L albeit of relatively short incubation of 7 days. With glycerol, intracellular lipid contents were ~1.9 times lower than glucose cases although similar cell growths were observed for both carbon sources.

줄기세포 연구 방법들에 대한 이해와 그 윤리적 쟁점들

이상목 한국의료윤리학회 2011 한국의료윤리학회지 Vol.14 No.4

While stem cell research offers great hope for the development of the life sciences and the discovery of medical treatments for a variety of diseases, it also raises many controversial ethical issues. The ethical issues raised by stem cell research can be divided into two broad categories. The first category consists of the controversies relating to the destruction of human embryos during the process of stem cell extraction. The second category involves the ethical questions surrounding the use of adult stem cells or induced pluripotent stem cells. This article provides an overview of the current state of stem cell research and an analysis of some of the associated ethical issues. Furthermore, on the basis of the analysis provided in this article, suggestions are offered concerning the best direction for future stem cell research. While stem cell research offers great hope for the development of the life sciences and the discovery of medical treatments for a variety of diseases, it also raises many controversial ethical issues. The ethical issues raised by stem cell research can be divided into two broad categories. The first category consists of the controversies relating to the destruction of human embryos during the process of stem cell extraction. The second category involves the ethical questions surrounding the use of adult stem cells or induced pluripotent stem cells. This article provides an overview of the current state of stem cell research and an analysis of some of the associated ethical issues. Furthermore, on the basis of the analysis provided in this article, suggestions are offered concerning the best direction for future stem cell research.

Choice of ATP-regenerating energy sources affects the solubility and functionality of cell-free synthesized proteins

권진호,김동명 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

In this study, a series of ATP-regenerating energy sources have been compared for their efficiency to support the generation of active proteins in a cell-free synthesis system. We found that the ATP profile and pH during cell-free protein synthesis(CFPS) substantially changes depending upon the methods for ATP regeneration. Among the energy sources examined, creatine phosphate(CP) provided most stable supply of ATP with minimal changes in pH during cell-free protein synthesis reactions. Although the use of CP did not always lead to the synthesis of target proteins at maximal yields, most likely due to the stable maintenance of pH, the proportion of the soluble or active proteins was substantially higher in the reaction mixture utilizing CP. The presented results suggest that the proper choice of energy source is important for the generation of active proteins in the CFPS system.

Methods for energizing cell-free protein synthesis

Kim, H.C.,Kim, D.M. Society for Bioscience and Bioengineering, Japan ; 2009 Journal of bioscience and bioengineering Vol.108 No.1

The productivity of cell-free protein synthesis depends critically upon the efficiency of ATP regeneration. In addition, the expensive energy sources used in the conventional cell-free protein synthesis systems account for the major part of the overall cost for the expression of proteins. Therefore, it is essential to implement a cheaper and more efficient ATP regeneration method in order to make cell-free protein synthesis a viable option for industrial protein production. In this article, we review the recent progress in the methodologies for supplying ATP during cell-free protein synthesis in E. coli extracts.

소아 급성골수성백혈병에서 조혈모세포 근원에 따른 이식 성적 비교

이혜령,한동균,백희조,김영옥,김석주,송은송,국훈,황태주 대한혈액학회 2005 Blood Research Vol.40 No.4

Purpose: Postremission therapy is critical for long-term survival in patients with acute myelogenous leukemia (AML). Allogeneic bone marrow transplantation in the first complete remission (CR) using HLA-identical sibling may offer the best chance for long-term leukemia-free survival. Patients without matched siblings may have several treatment options including intensive chemotherapy alone or myeloablative therapy followed by autologous or allogeneic stem cell rescue. The aim of this study was to compare clinical outcomes after matched sibling transplantation (MST), unrelated stem cell transplantation (non-MST), or autologous peripheral blood stem cell transplantation (APBSCT) as postremission therapy in patients with AML. Methods: Thirty four hematopoietic stem cell transplantations (SCT) in 32 children with AML were done between June, 1996 and December, 2004. Two patients who failed prior APBSCT underwent 2nd unrelated transplantations. Disease status at the time of transplant, conditioning regimen, graft-versus-host disease (GVHD) prophylaxis, the incidence of GVHD, complications, cause of death, over-all survival and event-free survival were retrospectively compared in relation with stem cell sources. Results: There were 19 males and 13 females with the median age of 8 yr 10 mo. The median follow-up was 17 mo. Twenty-eight cases were transplanted in CR1. Most cases (5/6) of patients other than CR1 were allocated in non-MST group. APBSCT was done in 17 cases, and allo-transplants in 17, which included MST in 10, matched-unrelated BM transplant in 5, haploidentical CD34+selected peripheral blood transplant in 1, and 1-antigen mismatch unrelated cord blood transplantation in 1. Acute GvHD ≥ Grade 2 were found in 20% in MST vs. 85.7% in non-MST (P<.01). Two-year cumulative relapse risks were 46.4% in APBSCT, 20% in MST and 31.5% in non-MST. The Kaplan-Meier 2-year EFS in all cases were 55.7%: 46.3% in APBMT, 80.0% in MST, and 68.6% in non-MST, despite higher proportion of high risk patients in non-MST group. Conclusion: This study indicated that MST was the best option for pediatric AML. For patients without matched siblings, unrelated transplants fared better survival and lower relapse than APBSCT. However, further prospective, randomized study incorporating a larger number of patients and cord blood transplant arm is necessary to definitely answer the best option for pediatric AML.