• Title/Summary/Keyword: screening

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Molecular Cloning and Expression in Escherichia coli of a Rabbit Globin Gene (유전공학적 방법에 의한 토끼 글로빈 유전자의 재조합과 대장균에서의 발현)

  • Jang, Sung-Key;Park, Hyune-Mo
    • The Korean Journal of Zoology
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    • v.27 no.2
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    • pp.103-116
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    • 1984
  • The structural gene of rabbit hemoglobin was cloned into Pst I site of pBR322 in E. coli. The complementary DNA (cDNA) was synthesized from rabbit globin mRNA with avian myeloblastosis viral reverse transcriptase, and then RNA was destroyed at pH 11. The double stranded cDNA was synthesized with both Klenow fragment of E. coli DNA polymerase I and reverse transcriptase and then the hairpin loop was opened with Sl nuclease. Double stranded cDNA was subsequently tailed with dCTP and annealed to dGMP-tailed vector DNA. After transformation and initial screening of appropriate clones by plasmid size, the cloned colonies were identified by in situ colony hybridization using by plasmid size, the cloned colonies were identified by in situ colony hybridization using $[^32P]$-labeled cDNA probes and characterized the inserts with restriction endonucleases. The expression of cloned globin gene was investigated by standard radioimmunoassay using rat anti-rabbit Hb serum as primary antibody and goat antirat IgG serum as secondary antibody. The result suggested that the chimeric proteins (the part of $\\beta$-lactamase from the vector pBR322 and globin from rabbit) were supposedly produced in E. coli and the product had the antigenic determinant of rabbit hemoglobin.

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The Detection of Irradiated Composite Seasoning Foods by Analyzing Photostimulated Luminescence (PSL), Electron Spin Resonance (ESR) and Thermoluminescence (TL) (PSL, ESR 및 TL 측정에 의한 복합조미식품의 방사선 조사여부 검지)

  • Kwon Joong-Ho;Kim Mi-Yeung;Kim Byeong-Keun;Chung Hyung-Wook;Kim Tae-Cheol;Kim Soo-Jin
    • Food Science and Preservation
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    • v.13 no.1
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    • pp.55-60
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    • 2006
  • Two kinds of composite seasoning products (beef broth powder, polk bone extract powder) were used for a detection trial of gamma irradiation treatment up to 10 kGy by analyzing photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence(TL). PSL results showed that the photon counts of non-irradiated samples were lower than 700, while those of irradiated samples were higher than 5000, which makes it possible to screen irradiated composite seasoning products at 1 kGy or over from the non-irradiated control. ESR signals measured for both irradiated samples were not irradiation-specific, even though they were dose dependent in the signal intensity. Radiation-induced TL glow curves were found in irradiated beef broth powder and furthernmore, TL ratio $(TL_4/TL_2)$ obtained by a re-irradiation step could verify the detection result of TL1 glow curves, showing ratios lower than 0.05 in the non-irradiated sample and higher than 1.00 in irradiated ones.

Radical scavenging and α-glucosidase inhibitory effects of Mongolian Iris bungei extract (몽골산 Iris bungei 추출물의 자유 라디칼 소거 및 α-glucosidase 저해 활성)

  • Jeong, Yun Hee;Jeong, Gyeong Han;Kim, Tae Hoon
    • Food Science and Preservation
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    • v.24 no.6
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    • pp.879-884
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    • 2017
  • In a continuing screening of selected medicinal plants native to Mongolia, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of methanol extract of Iris bungei were investigated. After extraction with 80% of methanol, the methanol fraction was further extracted with n-hexane, EtOAc and n-BuOH in order to obtain four different solvent-soluble fractions, namely n-hexane-soluble, EtOAc-soluble, n-BuOH-soluble and $H_2O$ residue. The antioxidant properties were evaluated by radical scavenging assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. The anti-diabetic efficacy of I. bungei extract was investigated by ${\alpha}$-glucosidase assay. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. Among the tested extracts, the EtOAc-soluble fractions showed the greatest radical scavenging activity and ${\alpha}$-glucosidase inhibitory properties among other solvent-soluble fractions. This result suggested that there was a significant relationship between the total phenolic content and biological efficacy. Thus, I. bungei extract might be considered as a new potential source of natural antioxidant and as a ${\alpha}$-glucosidase inhibitory source. A more systematic investigation of this biomass sill be performed for further investigation of activity against antioxidative and anti-diabetic effects.

Effect of commercial sanitizers on microbial quality of fresh-cut iceberg lettuce during storage (세척용 시판 살균제 종류에 따른 신선편의 양상추의 저장 중 미생물 변화)

  • Hwang, Tae-Young
    • Food Science and Preservation
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    • v.24 no.6
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    • pp.827-833
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    • 2017
  • This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

The Extracts from Natural Product Complex (DW) Suppress Lipid reroxidation and Inhibit Liver Fibrosis (Cirrhosis) in Rats (실험동물에서 복합천연물(DW)의 지질 과산화 억제와 간섬유화 저해 효과 검색)

  • 정재열;임진아;박선영;서의석;제갈승주;김기영
    • YAKHAK HOEJI
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    • v.45 no.5
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    • pp.513-521
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    • 2001
  • The chronic cholestasis induce to biliary liver fibrosis (cirrhosis) and the increased products of ROS(reactive oxygen species) cause to the liver damage. In this study ; the antioxidant and antifibrotic effect of dried extracts of oriental medicine (DW) was investigated under the liver fibrotic (cirrhotic) condition. The female Sprague-Dawley rats were divided in 5 groups (Normal, Op-2, Op-4, OpDW-2, OpDW-4). Except for normal group, the rats were induced to biliary liver fibrosis (cirrhosis) by the operation of bile duct ligation/scission (BDU/S) and were observed in 2 weeks or 4 weeks. And the prepared DW was treated p.o.2 ml/day/rats in 2 weeks or 4 weeks for OpDW groups. At the time of sacrifice, the liver, kidney, spleen were weighed and the ratio of organ weight/body weight was calculated. The MDA, the hyp and biochemical parameters (GOT GTP, ALP, t-bili) were measured in sera and liver tissue of rats. The biochemical change was observed on liver tissue. In the result, the hepatomegaly and spleenomegaly appeared in all BDL/S operated rats, and significantly lower liver weight was observed in OpDW-4 group compared with in Op-4 group (p<0.05). The level of clinical parameters in sera of all liver fibrosis (cirrhosis) developed rats was higher than in normal group. Especial1y, the value of GOT in OpDW-2 group and ALP in OpDW-4 group showed significantly lower than in Op-2 group and Op-4 group (p<0.01, p<0.005). The content of hyp in all operation groups was significantly higher than in normal group (p<0.05∼<0.005), and showed significantly lower value in the OpDW-4 group than in Op-4 group (p<0.05). The product of lipid peroxidationUDA) increased significantly under the fibrotic(cirrhotic) condition (p<0.05∼ <0.005), and the MDA value in OpDW-4 group decreased significantly in Op-4 group (p<0.005). The histological change (bile duct proliferation, fibrosis, collagen bundle) was similarly observed in Op-2 group and in OpDW-2 group, but the weak fibrosis and bile duct proliferation were observed in OpDW-4 group compared with in Op-4 group. In conclusion, lipid peroxidation and severe liver damage were activated by bile duct obstruction, and the measurement of MDA and hap can be useful monitor for the screening of antioxidant and antifibrotic effect in experimental liver fibrosis (cirrhosis). The 4 weeks treatment with DW extracts suppressed lipid peroxidation and inhibited fibrotic (cirrhotic) process in BDL/S operated rats.

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Screening of Staphylococcus aureus and Staphylococcal Enterotoxin a, b, c gene in Strains Isolated from Strawberry Farms in Western Gyeongnam (서부 경남지역 딸기 농장에서의 Staphylococcus aureus의 분리와 Staphylococcal enterotoxin a, b, c gene 검색)

  • Kim, Se-Ri;Shim, Won-Bo;Kim, Ji-Hun;Hwang, Seung-Jae;Park, Seon-Ja;Ha, Sang-Do;Kim, Keun-Sung;Lee, Kyu-Ho;Kim, Min-Gon;Kim, Kwang-Yup;Kim, Cheol-Ho;Chung, Duck-Hwa
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.321-327
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    • 2005
  • Staphylococcus aureus is spread worldwide and can result in food poisoning outbreaks. Among samples collected from soil, water, protected houses, packing houses, employees, strawberries, and leaves, and analyzed for S. aureus contamination, 16% samples 'showed S. aureus contamination, particularly on employees' hands, scissors, and strawberries. Examination of enterotoxins A, B, and C genes of S. aureus by PCR revealed sea and seb in 92 and 38% of total strains, respectively, whereas sec was not detected. In conclusion, implementation of Good Agricultural Practice is necessary for preventing food-borne diseases of staphylococcal origin, thereby ensuring the safety of farm-to-table products.

Potential Detection and Quality Properties of ${\gamma}-Irradiated$ Corn Starch of Korean and Chinese Origins by Viscosity Measurement during Storage (저장 기간 중 감마선 조사 옥수수 전분의 검지를 위한 점도 측정법의 적용과 품질특성)

  • Choi, Mal-Gum;Kwon, Joong-Ho;Kim, Hyun-Ku
    • Korean Journal of Food Science and Technology
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    • v.35 no.2
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    • pp.173-181
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    • 2003
  • Physicochemical changes in corn starch caused by irradiation were investigated, and irradiated samples were identified. Viscosity, TBA value, Hunter color, and total viable count were measured after irradiation of corn starch. Corn starches from Korea and China were irradiated at 0, 2.5, 5, 7.5, 10, and 15 kGy using a $Co^{60}$ irradiator and stored for 9 months at $0^{\circ}C$ and $20^{\circ}C$. Viscosity and specific parameter values decreased in all samples with increasing irradiation dosage at 50 rpm, showing a dose-dependent relationship $(above\;R^2=0.80)$ between non-irradiated and irradiated samples during storage. These results suggest that detection of irradiated corn starches is possible using viscometric method during storage. Total viable count, TBA value, and Hunter color were determined as supplemental indices for measuring viscosities of samples. Total viable count and TBA values showed dose-dependent relationship $(2.5{\sim}15 kGy)$. Differences in viscosity and total viable count, and TBA values among non-irradiated samples showed little changes with the lapse of post-irradiation time, but were still distinguishable for more than 6 months at $0^{\circ}C$ and $20^{\circ}C$ for corn starches from korea and China.

The STAR RNA Binding Proteins SAM68, SLM-1 and SLM-2 Interact with Kinesin-I (Kinesin-I과 직접 결합하는 STAR RNA 결합 단백질인 SAM68, SLM-1과 SLM-2의 규명)

  • Seog, Dae-Hyun
    • Journal of Life Science
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    • v.21 no.9
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    • pp.1226-1233
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    • 2011
  • In neurons, kinesin is the molecular motor that transport cargos along microtubules. KIF5s (alias kinesin-I), are heterotetrameric motor conveying cargos, but the mechanism as to how they recognize and bind to a specific cargos has not yet been completely elucidated. To identify the interaction proteins for KIF5C, yeast two-hybrid screening was performed, and specific interaction with the $\underline{S}$am68-$\underline{l}$ike $\underline{m}$ammalian protein $\underline{2}$ (SLM-2), a member of the $\underline{s}$ignal $\underline{t}$ransducers and $\underline{a}$ctivators of $\underline{R}$NA (STAR) family of RNA processing proteins, was found. SLM-2 bound to the carboxyl (C)-terminal region of KIF5C and to other KIF5 members. The C-terminal domain of Sam68, SLM-1, SLM-2 was essential for interaction with KIF5C in the yeast two-hybrid assay. In addition, glutathione S-transferase (GST) pull-downs showed that SAM68, SLM-1, and SLM-2 specifically interacted to Kinesin-I complex. An antibody to SAM68 specifically co-immunoprecipitated SAM68 associated with KIF5s and coprecipitated with a specific set of mRNA. These results suggest that Kinesin-I motor protein transports RNA-associated protein complex in cells.

Screening of Antimicrobial Activity Compounds from Korea Ginseng Fine Root (고려인삼의 세근을 이용한 항균성 물질 탐색)

  • Kim, Ah-Reum;Lee, Myung-Suk
    • Journal of Life Science
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    • v.21 no.9
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    • pp.1244-1250
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    • 2011
  • The study was performed to evaluate the antibacterial and antiviral activities of ginseng fine root in order to search for antibacterial substances. Among 8 kinds of fermentation strains, Lactobacillus plantarum was selected based on viable cell count and antibacterial activities during incubation. Optimum conditions of ginseng fine root fermentation for L. plantarum were incubation at $35^{\circ}C$ for 48 hr in 5% ginseng fine root broth. That methanolic extract of fermented ginseng fine root broth was observed to be antibacterial and have antiviral activities. The results of paper disc method of non-fermented extract and fermented extract measured against E. coli was 11 mm and 20 mm, S. aureus was 15 mm and 22 mm, respectively. Shaking flask method was observed to inhibit the growth E. coli and S. aureus in fermented extract by 99.9%. However, antiviral activity of Feline calicivirus (FCV) was mostly activated. Fermented extract was used to investigate the compositional changes of ginsenosides on HPLC analysis. By fermentation, ginsenoside Rg1, Re and Rd were increased, with Rd showing a significant increase of 50 ${\mu}g/g$. These results suggest that ginseng fine root extract is a useful resource.

Intersubunit Communication of Escherichia coli Tryptophan Synthase (대장균 트립토판 생성효소의 소단위체간 상호조절)

  • Cho, Won Jin;Lim, Woon Ki
    • Journal of Life Science
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    • v.27 no.12
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    • pp.1410-1414
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    • 2017
  • Escherichia coli tryptophan synthase (TS) contains ${\alpha}_2{\beta}_2$, which catalyzes the final two steps in Trp biosynthesis. A molecular tunnel exists between the two active sites of ${\alpha}$ and ${\beta}$ subunits in TS. Via intersubunit communication, TS increases catalytic efficiency, including substrate channeling. The ${\beta}$ subunit of TS is composed of two domains, one of which, the COMM (communication) domain, plays an important role in intersubunit communication. The ${\alpha}$ subunit has a TIM barrel structure. This protein has functional regions at the C terminal of ${\beta}$ pleated sheets and in its loop regions. Three regions of the ${\alpha}$ subunit (${\alpha}L6$ [${\alpha}-loop$ L6], ${\alpha}L2$, and ${\alpha}L3$) are implicated in intersubunit communication. In the present study, conformational changes in ${\alpha}L6$ were monitored by measuring the sensitivity of mutant proteins in these regions to trypsin. The addition of a ${\alpha}$ subunit-specific ligand, D,L-${\alpha}$-glycerophosphate (GP), partially restored the sensitivity of mutant proteins to trypsin. In contrast, the addition of the ${\beta}$ subunit-specific ligand L-serine (Ser) resulted in varied sensitivity to trypsin, with an increase in PT53 (substitution of Pro with Thr at residue 53) and DG56, decrease in NS104 and wild type, and no change in GD51 and PH53. This finding may be related to several reaction intermediates formed under this condition. The addition of both GP and Ser led to a highly stable state of the complex. The present results are consistent with the current model. The method used herein may be useful for screening residues involved in intersubunit communication.