Argyrins are a group of anticancer and antibacterial octapeptide bioactive substances isolated from myxobacteria. In this study, we showed that the myxobacterium Archangium gephyra MEHO_001, isolated ...in Korea, produces argyrins A and B. MEHO_001 cells tend to aggregate when cultured in liquid media. Hence, a dispersion mutant, MEHO_002, was isolated from MEHO_001. The MEHO_002 strain produced approximately 3.5 times more argyrins than that produced by the wild-type strain MEHO_001. We determined the whole-genome sequence of A. gephyra MEHO_002 and identified a putative argyrin biosynthetic gene cluster comprising five genes, arg1-arg5, encoding non-ribosomal peptide synthases and tailoring enzymes. Inactivation of arg2 by plasmid insertion disrupted argyrin production. The amino acid sequences of the proteins encoded by arg2-arg5 of A. gephyra MEHO_002 were 90-98% similar to those encoded by the argyrin biosynthetic genes of Cystobacter sp. SBCb004, an argyrin-producing myxobacterium with identical domain organization.
Argyrins are a group of anticancer and antibacterial octapeptide bioactive substances isolated from myxobacteria.
In this study, we showed that the myxobacterium Archangium gephyra MEHO_001, isolated ...in Korea, produces argyrins A and B. MEHO_001 cells tend to aggregate when cultured in liquid media.
Hence, a dispersion mutant, MEHO_002, was isolated from MEHO_001. The MEHO_002 strain produced approximately 3.5 times more argyrins than that produced by the wild-type strain MEHO_001. We determined the whole-genome sequence of A. gephyra MEHO_002 and identified a putative argyrin biosynthetic gene cluster comprising five genes, arg1-arg5, encoding non-ribosomal peptide synthases and tailoring enzymes.
Inactivation of arg2 by plasmid insertion disrupted argyrin production. The amino acid sequences of the proteins encoded by arg2-arg5 of A. gephyra MEHO_002 were 90-98% similar to those encoded by the argyrin biosynthetic genes of Cystobacter sp. SBCb004, an argyrin-producing myxobacterium with identical domain organization. KCI Citation Count: 0
Tubulysins are a group of secondary metabolites produced by myxobacteria that inhibit the function of the eukayotic cytoskeleton. We developed a pair of PCR primers that specifically amplified ...tubulysin biosynthetic genes. Using these primers, eight out of the eighty-one strains of myxobacteria belonging to the Cystobacteraceae family that harbored putative tubulysin biosynthetic genes were screened through PCR analysis. The selected strains included two Archangium gephyra, two Stigmatella sp., two Vitiosangium cumulatum, and two unidentified myxobacteria. LC-MS analysis of the culture extracts from the selected strains revealed that A. gephyra KYC4066 produced putative tubulysin A and B.
Tubulysin은 다양한 암세포주에 대해 강한 항암활성을 보이는 점액세균 유래 이차대사 생리활성물질이다. 본 연구에서는 tubulysin을 생산하는 두 균주의 점액세균 Archangium gephyra MEHO_002와 MEHO_004의 유전체 분석을 통해 tubulysin 생합성 유전자들로 추정되는 유전자군을 발견하였으며, 플라스미드 삽입에 의한 ...유전자 불활성화를 통해 이들 유전자들이 tubulysin 생산과 직접 연관되어 있음을 확인하였다. A. gephyra MEHO_002와 MEHO_004 균주의 tubulysin 생합성 유전자군(tubA~tubF)은 DNA 염기서열이 서로 97% 동일하였으며, 암호화하는 단백질들의 아미노산 서열도 서로 97-100% 유사하였다. MEHO_002와 MEHO_004 균주의 tubulysin 생합성 유전자군은 tubulysin 생산 점액세균으로 알려진 Cystobacter sp. SBCb004의 tubulysin 생합성 유전자군과 DNA 염기서열이 86% 동일하였다. 유전자군의 구성은 tubZ 유전자가 존재하지 않는다는 점을 제외하고는 SBCb004의 tubulysin 생합성 유전자군 구성과 동일하였다. 각 유전자가 암호화하는 단백질의 아미노산 서열은 Cystobacter sp. SBCb004의 tubulysin 생합성 유전자가 암호화하는 단백질들과 88-97% 유사하였으며, 각 단백질들의 도메인 구성도 동일하였다.
Tubulysins are a group of bioactive secondary metabolites from myxobacteria exhibiting strong anticancer activity against various cancer cell lines. In this study, we describe the identification of putative tubulysin biosynthetic gene clusters (tubA~tubF) in the genome sequences of two tubulysin-producing myxobacterial strains, Archangium gephyra MEHO_002 and MEHO_004. The inactivation of the putative tubulysin biosynthetic genes resulted in a tubulysin-production defect. The DNA sequences of the A. gephyra MEHO_002 and MEHO_004 tubulysin biosynthetic genes were 97% identical, and the amino acid sequences of the encoded proteins shared a similarity of 97-100%. The nucleotide sequences of the tubulysin biosynthetic gene clusters in MEHO_002 and MEHO_004 were 86% identical to that in Cystobacter sp. SBCb004 known as a tubulysin-producing myxobacterium, and the organization of the clusters was identical except for the lack of a tubZ gene in the clusters in MEHO_002 and MEHO_004. The amino acid sequences of the proteins encoded by each gene were 88-97% similar to those encoded by SBCb004, and the domain compositions of the proteins were also identical.
Tubulysins are a group of bioactive secondary metabolites from myxobacteria exhibiting strong anticancer activity against various cancer cell lines. In this study, we describe the identification of ...putative tubulysin biosynthetic gene clusters (tubA~tubF) in the genome sequences of two tubulysin-producing myxobacterial strains, Archangium gephyra MEHO_002 and MEHO_004. The inactivation of the putative tubulysin biosynthetic genes resulted in a tubulysin-production defect. The DNA sequences of the A. gephyra MEHO_002 and MEHO_004 tubulysin biosynthetic genes were 97% identical, and the amino acid sequences of the encoded proteins shared a similarity of 97−100%. The nucleotide sequences of the tubulysin biosynthetic gene clusters in MEHO_002 and MEHO_004 were 86% identical to that in Cystobacter sp. SBCb004 known as a tubulysin-producing myxobacterium, and the organization of the clusters was identical except for the lack of a tubZ gene in the clusters in MEHO_002 and MEHO_004. The amino acid sequences of the proteins encoded by each gene were 88-97% similar to those encoded by SBCb004, and the domain compositions of the proteins were also identical. KCI Citation Count: 0
Tubulysins are a group of secondary metabolites produced by myxobacteria that inhibit the function of the eukayotic cytoskeleton. We developed a pair of PCR primers that specifically amplified ...tubulysin biosynthetic genes. Using these primers, eight out of the eighty-one strains of myxobacteria belonging to the Cystobacteraceae family that harbored putative tubulysin biosynthetic genes were screened through PCR analysis. The selected strains included two Archangium gephyra, two Stigmatella sp., two Vitiosangium cumulatum, and two unidentified myxobacteria. LC-MS analysis of the culture extracts from the selected strains revealed that A. gephyra KYC4066 produced putative tubulysin A and B. KCI Citation Count: 1
A thermoeconomic analysis of an ocean thermal energy conversion (OTEC) system was performed using the modified productive structure analysis (MOPSA) method. In this analysis, the unit cost of ...electricity from the 20-kW OTEC pilot plant built and operated at the Korea Research Institute of Ships and Ocean Engineering was estimated. The unit cost of electricity from the OTEC plant with thermal efficiency of 0.66% is approximately $0.363/kWh. The unit cost of electricity of the OTEC plant increases linearly with the unit cost of supplied heat to the evaporator and increases inversely to the exergy efficiency of the system independently. The OTEC system was found to be economically viable renewable energy source in the regions where the temperature of warm sea water remains to be 25 °C and the condenser effluent from a power plant is available.
•20-kW ocean thermal energy conversion (OTEC) plant was built and operated.•Thermal efficiency of 0.66% was obtained for the OTEC plant with temperature difference of 22 K.•Thermoeconomic analysis of the OTEC plant was performed based on the obtained data.•Unit cost of electricity from the OTEC plant is approximately $0.363/kWh.•Unit cost of electricity increased linearly with the unit cost of heat supplied to the evaporator.
•Integration of new and renewable energy systems (NRESs) in public buildings is studied.•The utilization factor of NREs depends on the energy demand patterns for the buildings.•Unit cost for the ...products from NRESs depends on the utilization factor of NERSs.•Proper mix of NRES for public buildings was determined by the unit cost of products from NRESs.
Public buildings in Korea have an obligation to supply 10% of the total energy consumption from new and renewable energy sources, which requires proper tools for installation of the energy systems. In this study, a cost-effective method for integration of existing grids with new and renewable energy sources in public buildings in Korea is suggested. A key factor of the method is based on the fact that the unit costs of the products from the energy systems depends on the capacity factor or the utilization factor which is crucially dependent on the interaction between the energy demand pattern for the building and the production time of the specific energy from the new and renewable energy sources. For several public buildings such as two business buildings located at quite different weather conditions, a welfare center and a fire station at different locations, the proper combination of new and renewable energy sources is suggested by detailed numerical calculation based on the hourly energy demand pattern data obtained from field studies for the buildings to minimize the additional cost by installing the energy systems.
Various policies such as feed-in tariffs, quota obligations and capital subsides were enacted to expand the uses of renewable energy (RE) in many countries. This study examined whether capital ...subsidies are cost effective in relation to the installation of solar photovoltaic (PV) facility. To do this, the capacity factor, which is one of the crucial factors for determining the unit cost of electricity from a solar PV system, was estimated from the monthly average clearness index data collected at various cities in Korea. Thermoeconomic analysis was applied to calculate the unit cost of electricity based on the calculated capacity factor of the solar PV system. Instead of subsidizing the same percent of the capital cost of each PV system installation, it is reasonable for the government to adopt a measure to match the subsidy paid to the payback period of the initial investment for all 5 million potential solar PV users in Korea.
► The unit cost of electricity from solar PV depends crucially on its capacity factor. ► We calculated the capacity factor of solar PV at various cities from the clearness index. ► We estimated the unit cost of electricity from solar PV using thermoeconomic analysis. ► We examined whether the capital subsidy program in Korea to solar PV is cost effective. ► This study determined that a measure based on the same payback period is better policy.
An ideal off-grid island can become 100% energy-sufficient if one installs renewable energy systems such as solar photovoltaic (PV) and wind turbine (WT) systems. However, the intermittent and ...uncertain nature of the power supply from renewable energy systems hinders a 100% autonomy level (AL) without an infinite energy storage capacity. The thermoeconomic installation limit (TEIL) of a PV/WT hybrid energy system was studied using hourly weather data and the energy demand profile for off-grid islands. An appropriate battery size for the TEIL was also determined. Given the current installation cost of the hybrid energy system and the battery unit, the AL for a PV/WT hybrid energy system at the TEIL is calculated to be approximately 70%. Above the limit, the size of the energy storage unit and, correspondingly, the total annual cost of the PV/WT hybrid energy system increase sharply.
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