• BMB Reports
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• 제38권6호
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• pp.683-689
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• 2005

Antibody to hepatitis B surface antigen (HBsAb) is the important serological marker of the hepatitis B virus (HBV) infection. Conventionally, the hepatitis B surface antigen (HBsAg) obtained from the plasma of HBV carriers is used as the diagnostic antigen for detection of HBsAb. This blood-origin antigen has some disadvantages involved in high cost, over-elaborate preparation, risk of infection, et al. In an attempt to explore the suitable recombinant HBsAg for the diagnostic purpose, the HBV S gene was expressed in Pichia pastoris and the product was applied for detection of HBsAb. Hepatitis B virus S gene was inserted into the yeast vector and the expressed product was analyzed by sodium dodecyl sulphate polyacrolamide gel electrophoresis (SDS-PAGE), immunoblot, electronic microscope and enzyme linked immunosorbent assay (ELISA). The preparations of synthesized S protein were applied to detect HBsAb by sandwich ELISA. The S gene encoding the 226 amino acid of HBsAg carrying ahexa-histidine tag at C terminus was successfully expressed in Pichia pastoris. The His-Tagged S protein in this strain was expressed at a level of about 14.5% of total cell protein. Immunoblot showed the recombinant HBsAg recognized by monoclonal HBsAb and there was no cross reaction between all proteins from the host and normal sera. HBsAb detection indicated that the sensitivity reached 10 mIu (micro international unit)/ml and the specificity was 100% with HBsAb standard of National Center for Clinical Laboratories. A total of 293 random sera were assayed using recombinant S protein and a commercial HBsAb ELISA kit (produced by blood-origin HBsAg), 35 HBsAb positive sera and 258 HBsAb negative sera were examined. The same results were obtained with two different reagents and there was no significant difference in the value of S/CO between the two reagents. The recombinant HBV S protein with good immunoreactivity and specificity was successfully expressed in Pichia pastoris. The reagent for HBsAb detection prepared by Pichia pastoris-derived S protein showed high sensitivity and specificity for detection of HBsAb standard. And a good correlation was obtained between the reagent produced by recombinant S protein and commercial kit produced by blood-origin HBsAg in random samples.

• BMB Reports
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• 제39권1호
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• pp.9-15
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• 2006

To prove whether error catastrophe /lethal mutagenesis is the primary antiviral mechanism of action of ribavirin against foot-and-mouth disease virus (FMDV). Ribavirin passage experiments were performed and supernatants of $Rp_1$ to $Rp_5$ were harvested. Morphological alterations as well as the levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected using the supernatants of $Rp_1$ to $Rp_5$ and control were measured by microscope, real-time RT-PCR, western-blotting and plaque assays, respectively. The mutation frequency was measured by sequencing the complete P1- and 3D-encoding region of FMDV after a single round of virus infection from ribavirin-treated or untreated FMDV-infected cells. Ribavirin treatment for FMDV caused dramatically inhibition of multiplication in cell cultures. The levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected were more greatly reduced along with the passage from $Rp_1$ to $Rp_5$, moreover, nucleocapsid protein could not be detected and no recovery of infectious virus in the supernatant or detection of intracellular viral RNA was observed at the $Rp_5$-infected cells. A high mutation rate, giving rise to an 8-and 11-fold increase in mutagenesis and resulting in some amino acid substitutions, was found in viral RNA synthesized at a single round of virus infection in the presence of ribavirin of $1000\;{\mu}M$ and caused a 99.7% loss in viral infectivity in contrast with parallel untreated control virus. These results suggest that the antiviral molecular mechanism of ribavirin is based on the lethal mutagenesis/error catastrophe, that is, the ribavirin is not merely an antiviral reagent but also an effective mutagen.

• BMB Reports
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• 제39권4호
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• pp.432-440
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• 2006

A tuber lectin from Arisaema jacquemontii Blume belonging to family Araceae was purified by employing a single step affinity chromatography using column of asialofetuin-linked amino activated silica beads and the bound lectin was eluted with 100 mM glycine-HCl buffer pH 2.5. The purified A. jacquemontii lectin (AJL) showed a single protein band with an apparent molecular mass of 13.4 kDa when submitted to SDS-polyacrylamide gel electrophoresis under reducing as well as non-reducing conditions. The native molecular mass of AJL determined by gel filtration on a Biogel P-200 column was 52 kDa and its carbohydrate content was estimated to be 3.40%. Thus AJL is a tetrameric glycoprotein. The purified lectin agglutinated erythrocytes from rabbit but not from human. Its activity was not inhibited by any of the mono- and disaccharides tested except N-acetyl-D-lactosamine having minimal inhibitory sugar concentration (MIC) 25 mM. Among the glycoproteins tested only asialofetuin was found to be inhibitory (MIC $125\;{\mu}g/mL$). A single band was obtained in native PAGE at pH 4.5 while PAGE at pH 8.3 showed two bands. Isoelectric focusing of AJL gave multiple bands in the pI range of 4.6-5.5. When incorporated in artificial diet AJL significantly affected the development of Bactrocera cucurbitae (Coquillett) larvae indicating the possibility of using this lectin in a biotechnological strategy for insect management of cucurbits. Larvae fed on artificial diet containing sub-lethal dose of AJL showed a significant decrease in acid phosphatase and alkaline phosphatase activity while esterase activity markedly increased as compared to larvae fed on diet without lectin. Out of various human cancer cell lines employed in sulphorhodamine B (SRB) assay, this lectin was found to have appreciable inhibitory effect on the in vitro proliferation of HCT-15, HOP-62, SW-620, HT-29, IMR-32, SKOV-3, Colo-205, PC-3, HEP-2 and A-549 cancer cell lines by 82, 77, 73, 70, 41, 41, 37, 29, 21 and 21% respectively.

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.135-143
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• 2017

Chemical Exchange Saturation Transfer (CEST) imaging is a method to detect solutes based on the chemical exchange of mobile protons with water. The solute protons exchange with three different patterns, which are fast, slow, and intermediate rates. The CEST contrast can be obtained from the exchangeable protons, which are hydroxyl protons, amine protons, and amide protons. The CEST MR imaging is useful to evaluate tumors, strokes, and other diseases. The purpose of this study is to review the mathematical model for CEST imaging and for measurement of the chemical exchange rate, and to measure the chemical exchange rate using a 3T MRI system on several amino acids. We reviewed the mathematical models for the proton exchange. Several physical models are proposed to demonstrate a two-pool, three-pool, and four-pool models. The CEST signals are also evaluated by taking account of the exchange rate, pH and the saturation efficiency. Although researchers have used most commonly in the calculation of CEST asymmetry, a quantitative analysis is also developed by using Lorentzian fitting. The chemical exchange rate was measured in the phantoms made of asparagine (Asn), glutamate (Glu), ${\gamma}-aminobutyric$ acid (GABA), glycine (Gly), and myoinositol (MI). The experiment was performed at a 3T human MRI system with three different acidity conditions (pH 5.6, 6.2, and 7.4) at a concentration of 50 mM. To identify the chemical exchange rate, the "lsqcurvefit" built-in function in MATLAB was used to fit the pseudo-first exchange rate model. The pseudo-first exchange rate of Asn and Gly was increased with decreasing acidity. In the case of GABA, the largest result was observed at pH 6.2. For Glu, the results at pH 5.6 and 6.2 did not show a significant difference, and the results at pH 7.4 were almost zero. For MI, there was no significant difference at pH 5.6 or 7.4, however, the results at pH 6.2 were smaller than at the other pH values. For the experiment at 3T, we were only able to apply 1 s as the maximum saturation duration due to the limitations of the MRI system. The measurement of the chemical exchange rate was limited in a clinical 3T MRI system because of a hardware limitation.

• 한국토양비료학회지
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• 제23권3호
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• pp.214-219
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• 1990

빨간지렁이와 그분(糞)의 특성(特性)을 구명(究明)하기 위하여 제지박(製紙粕), 제지박(製紙粕)(50)+스럿지(50), 우분(牛糞)(50)+스럿지(50)으로 처리(處理)하여 6개월간 조사(調査)한 결과(結果)는 다음과 같다. 1. 지렁이의 생육적온(生育適溫)은 $16{\sim}25^{\circ}C$였으며,월평균증체량(月平均增體量)은 $m^2$당(當) 1kg 정도였다. 2. 제지박(製紙粕) 단일처리에 비(比)하여 제지박(製紙粕)(50)+스럿지(50) 처리(處理), 우분(牛糞)(50)+스럿지(50)처리(處理)에서 각각 9~11% 증가(增加)되었다. 3. 지렁이에는 필수(必須) 아미노산인 lysine의 함량(含量)이 건물중당 3% 정도로 많아 사료첨가제(飼料添加製)로의 이용가치(利用價値)가 매우 높을 것으로 추정되었다. 4. 지렁이분(糞) 생산량(生産量)은 건물중(乾物重)으로 연간(年間) 10a당 90~95톤이었다. 5. 지렁이엽(糞)은 CEC(19.4~49.9me/100g)및 각종 무기물(無機物) 함량(含量)이 높아 비료자원(肥料資源)으로의 활용가치(活用價値)가 높을 것으로 보인다.

• International Journal of Industrial Entomology and Biomaterials
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• 제17권1호
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• pp.125-129
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• 2008

The purpose of this study was to investigate the characteristics of Mamestra brassicae nucleopolyhedrovirus (MabrNPV)-K1 isolated in Korea. Polyhedra of MabrNPV-K1 showed irregular appearance in shape with the average diameter $1.8{\mu}m$. MabrNPV-K1 contained a number of nucleocapsids within a viral envelope embedded in polyhedron. The polyhedrin of MabrNPV-K1 was composed of single polypeptide with a M.W. of approximate 31 kDa which is identical to the commercialized MabrNPV, Mamestrin, as a biological control agent. The nucleotide and amino acid sequences within the coding region of MabrNPV-K1 polyhedrin shared 99.0% similarity with the polyhedrin gene from previous reported MabrNPVs. The median lethal concentrations ($LC_{50}$) of MabrNPV-K1 and Mamestrin to M. brassicae larvae were $3.9{\times}10^3$ PIBs/larva and $6.0{\times}10^4$ PIBs/larva, respectively. Mortality of the MabrNPV-K1 against to the third instars larvae was 15 times higher than that of the Mamestrin. The median lethal times ($LT_{50})$ of MabrNPV-K1 by the concentration of polyhedra were lower ($4.4{\sim}6.1$ days) than those of Mamestrin ($4.1{\sim}8.6$ days). These results suggest that a local strain MabrNPV-K1 has high pathogenicity to M. brassicae and may be useful for the development of biological control agent to control this.

• The Plant Pathology Journal
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• 제25권4호
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• pp.344-351
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• 2009

A biocontrol bacterium Bacillus licheniformis N1 grown in nutrient broth showed no chitinolytic activity, while its genome contains a gene which encodes a chitinase. The gene for chitinase from B. licheniformis N1 was amplified by PCR and the deduced amino acid sequence analysis revealed that the chitinase exhibited over 95% identity with chitinases from other B. licheniformis strains. Escherichia coli cells carrying the recombinant plasmid displayed chitinase activity as revealed by the formation of a clear zone on chitin containing media, indicating that the gene could be expressed in E. coli cells. Chitinase gene expression in B. licheniformis N1 was not detected by RT-PCR analysis. The protein was over-expressed in E. coli BL21 (DE3) as a glutathione S-transferase fusion protein. The protein could also be produced in B. subtilis 168 strain carrying the chitinase gene of N1 strain. The crude protein extract from E. coli BL21 carrying GST fusion protein or culture supernatant of B. subtilis carrying the chitinase gene exhibited enzyme activity by hydrolyzing chitin analogs, 4-methylumbelliferyl-$\beta$-D-N,N'-diacetylchitobioside and 4-methylumbelliferyl-$\beta$-D-N,N',N"-triacetylchitotrioside. These results indicated that even though the chitinase gene is not expressed in the N1 strain, the coding region is functional and encodes an active chitinase enzyme. Furthermore, B. subtilis 168 transformants expressing the chitinase gene exhibited antifungal activity against Fulvia fulva by suppressing spore germination. Our results suggest that the proper engineering of the expression of the indigenous chitinase gene, which will lead to its expression in the biocontrol strain B. licheniformis N1, may further enhance its biocontrol activity.

• 식물병연구
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• 제19권4호
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• pp.326-330
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• 2013

2012년 국내 양앵두나무에서 발생하는 CGRMV를 조사하기 위해 화성, 평택, 경주, 김천, 대구, 영주 음성의 양앵두 재배과원 7개 지역에서 잎 시료 154점을 채집하였다. 채집한 시료에 대해 CGRMV 유전자 검정을 수행한 결과 6점의 시료에서 807 bp 크기의 PCR 증폭산물이 검출되었다. 이들 PCR 증폭산물은 클로닝과 유전자 염기서열 분석 결과 GeneBank에 등록된 외국의 CGRMV 분리주들과 88% 이상의 외피단백질 유전자 염기서열 상동성을 보였다. 국내 양앵두나무에서 분리된 분리주들, CGR-KO 1-6 간에는 98.8-99.8%의 염기서열 및 99.6-100%의 아미노산 서열 상동성을 나타내었다. 국내 CGRMV 분리주들은 외피단백질 유전자 계통도 분석에서 기존에 분류된 I, II, III 그룹 중 II 그룹에 속하였다. 또한 CGRMV가 감염된 국내 양앵두나무 이병주들은 ACLSV 등 10종 바이러스에 대해서도 RT-PCR을 수행한 결과 모든 시료에서 ACLSV가 검출되어 CGRMV와 ACLSV가 복합 감염된 것을 확인하였다.

• ALGAE
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• 제30권3호
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• pp.233-239
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• 2015

Microalgae research is gaining momentum because of their potential biotechnological applications, including the generation of biofuels. Genome sequencing analysis of two model microalgal species, polar free-living Coccomyxa sp. C-169 and symbiotic Chlorella sp. NC64A, revealed insights into the factors responsible for their lifestyle and unravelled biotechnologically valuable proteins. However, genome sequence analysis under-explored cytochrome P450 monooxygenases (P450s), heme-thiolate proteins ubiquitously present in species belonging to different biological kingdoms. In this study we performed genome data-mining, annotation and comparative analysis of P450s in these two model algal species. Sixty-nine P450s were found in two algal species. Coccomyxa sp. showed 40 P450s and Chlorella sp. showed 29 P450s in their genome. Sixty-eight P450s (>100 amino acid in length) were grouped into 32 P450 families and 46 P450 subfamilies. Among the P450 families, 27 P450 families were novel and not found in other biological kingdoms. The new P450 families are CYP745-CYP747, CYP845-CYP863, and CYP904-CYP908. Five P450 families, CYP51, CYP97, CYP710, CYP745, and CYP746, were commonly found between two algal species and 16 and 11 P450 families were unique to Coccomyxa sp. and Chlorella sp. Synteny analysis and gene-structure analysis revealed P450 duplications in both species. Functional analysis based on homolog P450s suggested that CYP51 and CYP710 family members are involved in membrane ergosterol biosynthesis. CYP55 and CYP97 family members are involved in nitric oxide reduction and biosynthesis of carotenoids. This is the first report on comparative analysis of P450s in the microalgal species Coccomyxa sp. C-169 and Chlorella sp. NC64A.

• 한국식품영양학회지
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• 제16권4호
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• pp.379-387
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• 2003

동결건조 녹용을 물과 단백질 가수분해 효소로 추출하였다. 동결건조녹용을 물추출하는 경우, 추출효율은 5% 농도로 5$0^{\circ}C$에서 6시간 추출하는 것이 가장 높았다. 추출물을 HPLC 분석한 결과, 물추출액에 존재하던 고분자 단백질은 단백질 가수분해 효소에 의해 저분자화되었다. 저분자화율은 세균 protease를 사용한 경우가 가장 높고 다음 pepsin인데, papain의 효과는 적었다. 생녹용에 단백질 가수분해 효소를 5시간 작용시켜서 얻은 추출액의 추출율은 세균 protease는 33.4% (280nm의 흡광도 13.25), papain은 22.4%(흡광도 10.06), pepsin은 30.2%(흡광도 11.34)였다. 30분 동안 끓인 녹용에 단백질 가수분해 효소를 5시간 작용시킨 용액의 추출율은 세균 protease는 47.6%(흡광도 12.54), papain은 26.4%(흡광도 7.48), pepsin은 45.6%(흡광도 7.23)였다. 단백질함량은 물추출액은 52.1%, 세균 protease 추출액은 37.8%였고, 아미노산 함량은 물추출액은 16.3%, 세균 protease 추출액은 31.9%였다. 회분함량은 물추출액은 8.8%, 세균 protease 추출액은 5.6%였다. 무기물 함량은 물추출액의 경우 Ca 3.6%, P 8.6%, Mg0.01%, Na 1.4%, F 0.02%, 세균 pretense의 경우 Ca 2.5%, P 11.8%, Mg 0.046%, Na 2.1%, F 0.018%였다.