• Journal of Microbiology and Biotechnology
• /
• v.17 no.9
• /
• pp.1460-1468
• /
• 2007

In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

• Korean Journal of Veterinary Research
• /
• v.37 no.3
• /
• pp.541-546
• /
• 1997

There are two conserved regions with a significantly high amino acid sequence homology among the A subunits of STX, SLTs and ricin. To produce an inactive Verotoxin-2 (VT-2), two different mutants, pE167D and pDE5A, were constructed by site-directed mutagenesis, respectively, on the basis of the previous reports that two regions lie within the active-site clefts of the A subunits of ricin and STX family. The cytotoxicity ($10^3$ $CD_{50}/ml$) of VT-2 holotoxin with E167D mutation was reduced by $10^3$-fold compared with wild-type level. In addition, VT-2 with DE5A ($Trp_{202}GlyArgIleSer_{206}$) deletion mutation showed a significantly low cytotoxicity ($10^1$ $CD_{50}/ml$), resulting in $10^5$- and $10^2$-fold reductions, respectively, compared with the wild-type and E167D mutatant. SDS-PAGE for protein samples showed a 33-kDa band corresponding to the A subunit of VT-2. These results indicate that reduction in cytotoxic activity was affected not by amount of VT-2 protein produced but by mutation.

• Applied Biological Chemistry
• /
• v.38 no.2
• /
• pp.118-122
• /
• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• Journal of the Korean Magnetics Society
• /
• v.7 no.4
• /
• pp.191-195
• /
• 1997

$Co_{84}Hf_{16}$ (1300$\AA$, 2150$\AA$) thin films were prepared by dc magnetron sputtering method. To investigate the uniaxial anisotrpy of the sample, the saturation and effective magnetization of the thin films were measured by VSM and FMR, respectively. The spectroscopic splitting g factor were estimated from the ferromagnetic resonance curves. For 1300$\AA$, 2150$\AA$, the effective magnetization was measured at the temperatures from T=77K to T=300K. The results were analyzed in terms of Bloch's law $M_s(T)=M_s(0)(1BT^{3/2}CT^{5/2}$. The Bloch coefficient B and C were determined by fitting. $M_{eff}(0)$ was obtained by extrapolating $M_{eff}$ to 0 K. From this result, the spinwave stiffness constants D was also determined and the exchange stiffness constants $A_{eff}$ were calculated by Kittel's resonance conditions.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.7
• /
• pp.455-463
• /
• 2001

In this Paper, an approximate processing method is proposed and tested. The proposed method uses variable CSD (VCSD) coefficients which approximate filter stopband attenuation by controlling the precision of the CSD coefficient sets. A decimation filter for Audio Codec '97 specifications has been designed having processor architecture that consists of program/data memory, arithmetic unit, energy/level decision, and sinc filter blocks, and fabricated with 0.6${\mu}{\textrm}{m}$ CMOS sea-of-gate technology. For the combined two halfband FIR filters in decimation filter, the number of addition operations were reduced to 63.5%, 35.7%, and 13.9%, compared to worst-case which is not an adaptive one. Experimental results show that the total power reduction rate of the filter is varying from 3.8 % to 9.0 % with respect to worst-case. The proposed approximate processing method using variable CSD coefficients is readily applicable to various kinds of filters and suitable, especially, for the speech and audio applications, like oversampling ADCs and DACs, filter banks, voice/audio codecs, etc.

• Journal of Convergence for Information Technology
• /
• v.7 no.4
• /
• pp.83-89
• /
• 2017

This study aims to investigate the impact of a mobile-based human coaching healthcare service provided for diabetic patients by nurses on their self-management ability. This study collected data from 311 persons who were diagnosed with diabetes from all over the country, and the collected data were analyzed through SPSS Win 23. The results of the study are summarized as follows: First, it was found that the utilization of a glucose meter by the provision of the mobile-based human coaching healthcare service was men group, and there was a statistically significant difference (${\chi}^2=6.059$, p= .048*). Second, there was a positive correlation in the utilization between the glucose meter and an activity tracker band by the provision of the mobile-based human coaching healthcare service, which was statistically significant (r=.660, p< .001). Third, as a result of checking the changes of the utilization of the glucose meter by the provision of the mobile-based human coaching healthcare service, it was maintained between 79% and 41% from Week 1 through 49. In conclusion, this study partially confirmed that the mobile-based human coaching health service was easily accessible and cost-effective in enhancing the participants'self-healthcare ability.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.151-151
• /
• 2013

무기물 기반, Si-based 태양전지에 비해 가볍고 저렴하다는 관점에서 유기태양전지에 대한 연구가 진행되고 있다. 유기태양전지는 Si-based 태양전지에 비해 그 효율이 낮다는 점이 문제로 제기되어 왔지만, 억셉터와 도너의 nanocomposite 구조인 bulk-heterojunction (BHJ) 구조가 개발이 되면서 유기물의 짧은 엑시톤(exciton) 거리를 극복할 수 있게 되어 그 효율이 비약적으로 증가되는 결과를 낳았다. 또한 넓은 범위의 파장을 흡수 할 수 있는 작은 band-gap을 갖는 물질이 개발됨으로써 유기 태양전지의 효율은 점차 증가하고 있다. 최근에는 독일 회사인 Heliatek에서 12%가 넘는 유기태양전지를 발표함으로써 유기태양전지가 Si-based 태양전지를 대체할 수 있는 차세대 에너지 공급원으로의 가능성을 충분히 보였다. 이런 유기 태양전지는 하부 투명전극인 인듐주석산화물(ITO)/정공이동층(PEDOT:PSS)/광흡수층/전자이동층(LiF)/낮은 일함수를 갖는 상부전극인 Al 구조의 일반적인 구조; ITO/전자이동층/광흡수층/정공이동층/높은 일함수를 갖는 상부전극(Ag), 전하의 이동방향이 반대인 역구조 태양전지, 두 가지로 분류할 수 있다. 하지만 소자 안정성의 관점에서 일반적인 구조의 태양전지는 ITO/PEDOT:PSS 계면에서의 화학적 불안정성과, 낮을 일함수를 갖는 상부전극이 쉽게 산화되는 등의 문제가 있어 상부전극으로 높은 일함수를 갖는 전극을 사용하는 역구조 태양전지가 더 유리하다. 이러한 역구조 태양전지에서 효율을 높일 수 있는 요인 중 하나는 전자이동층에 있다. 광흡수층에서 형성되어 분리된 전자가 전극으로 이동하기위해서는 전자이동층을 거쳐야 한다. 하지만 이 전자이동층 내에서의 전자 이동속도가 느리다면, 즉 저항이 크다면 광흡수증과의 계면에서 Back electron trasnfer현상으로 재결합이 일어나게 되어 전극으로 도달하는 전자의 양이 줄어들게 되고, 이는 유기태양전지 효율을 낮추는 요인이 된다. 전자이동층 자체의 저항뿐만 아니라, 전자이동층의 표면 거칠기(morphology) 또한 유기 태양전지의 효율을 좌우하는 요인 중 하나이다. 광흡수층과 전자이동층의 계면에서 전자의 이동이 일어나는데, 전자이동층의 표면 거칠기가 크게되면 그 위에 박막으로 형성되는 광흡수층과의 계면저항이 증가하게 되고, 이는 광흡수층에서 전자이동층으로의 원활한 전자이동을 저해함으로써 소자 효율의 감소를 일으키게 된다. 따라서 우리는 전자이동층인 ZnO 박막의 스퍼터링 조건을 변화시킴으로써 ZnO 층의 두께에 따른 광투과도, 전기전도성 변화 및 유기태양전지의 효율변화와, 표면 거칠기에 따른 광변환 효율 변화를 관찰하고자 한다.

• Journal of fish pathology
• /
• v.31 no.1
• /
• pp.9-13
• /
• 2018

We previously monitored nervous necrosis virus (NNV) in brain samples of artificially produced walleye Pollock (Gadus chalcogrammus) seedlings, with a low prevalence (1.8%, 1/55) but no clinical symptoms. Given that this virus is considered one of the most serious viral threats for almost all marine aquaculture fish species and characterized by both vertical and horizontal transmission, it would be interesting to monitor NNV in the fertilized eggs as well. We collected fertilized walleye pollock eggs from the farms located in Goseong during January to March, 2017. Approximately 50 mg of eggs were periodically taken from 4 each different batches, and 37 different pooled sample sets in total were made during sampling period. RNA was extracted from the eggs by using Trizol and cDNA was synthesized for RT-PCR for detecting NNV. Primers and PCR conditions are the same as previously described. As a result, NNV was not detected from any of the sample sets by one step PCR (0%, 0/37), suggesting NNV may not be a threat in walleye pollock aquaculture in Korea at present time. However, continuous monitoring for NNV should be conducted because introducing a new species into aquaculture industry involves potentials of disease outbreak and NNV is already known to cause outbreaks in gadoid fishes.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.4
• /
• pp.375-383
• /
• 2009

This study was carried out to develop transgenic rice cultivars with the CAX1 (accession no. U57411) gene. We successfully selected the transgenic rice plants over-expressing the Arabidopsis H+/$Ca^{2+}$ antiporter CAX1 (accession no. U57411) gene in T6 generation. The brown rice of the CAX1 expressing rice contained 13.4~68.0 % more calcium $(Ca^{2+})$ than that of the wild type and 5 lines were selected based on the phenotypes compared to the control cultivar at the GMO field. The CAX1 expressing transgenic rice plants were similar in phenotype to the wild type during the whole growth period. Also these selected 4 lines appeared to be resistant to blast, cold and water solution compared with the wild type. Difference in 1,000 grain weight of brown rice was observed among each line but grain shape did not show any morphological alternations. These results suggest the enhanced Ca-substrate specificity of CAX1 exchanger in donor plant. Therefore, intact CAX1 exchanger can be functionally useful for $Ca^{2+}$ nutrient enrichment of rice with reduced accumulation of undesirable cation.

• The Korean Journal of Food And Nutrition
• /
• v.20 no.1
• /
• pp.79-87
• /
• 2007

An evaluation of the influence of nutritional health camp for in obese elementary students was assessed. Anthropometric measurement, 24-hour recall of dietary intake, MMTIC(Murphy-Meisgeier Type Indicator for Children) and questionnaire response(nutritional knowledge, nutritional attitude, and self-satisfaction) was documented in 43 obese elementary students(29 boys and 14 girls). The mean age of the elementary students was 11.2 years. The mean height, body weight and obesity index was 144.7 cm, 55.4 kg and 41.0% in boys, and 136.1 cm, 45.2 kg, 40.0% in girls. The mean energy intake was 1,522.4 kcal in boys and 1,494.9 kcal in girls. The subjects taking less than estimated average requirement(EAR) for vitamin ${B_2}$, folate, vitamin C and calcium was over 70%. A considerable number of students(65.1%) showed U band(undetermined character). The students demonstrated a propensity towards increased average nutritional knowledge and self-satisfaction after attending the nutritional health camp. In addition, a significant increase in average nutritional attitude was observed(p<0.001). The results of this study suggest that nutritional health camp positively influenced the nutritional attitude of elementary students.