• Title/Summary/Keyword: research activity

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Gene Cloning, Expression, and Characterization of Glucose-1-Phosphatase from Enterobacter cloacae B11

  • Kim, Young-Ok;Park, In-Suk;Nam, Bo-Hye;Kong, Hee-Jeong;Kim, Woo-Jin;Lee, Sang-Jun;Kim, Kyung-Kil
    • Fisheries and Aquatic Sciences
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    • v.13 no.1
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    • pp.49-55
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    • 2010
  • A bacterial strain with phytase and glucose-1-phosphatase activity was isolated from seawater. The colony was identified as an Enterobacter cloacae strain and named E. cloacae B11. A gene, agpEnB11, coding for an intracellular acid glucose phosphatase was cloned from the strain and sequenced. It comprised 1,242 nucleotides and encoded a polypeptide of 413 amino acids. Recombinant glucose-1-phosphatase (AgpEn) was overexpressed in Escherichia coli and purified using Ni-NTA column under native conditions. Purified protein displayed a single band of 47 kDa on SDS-PAGE. AgpEn hydrolyzed a wide variety of phosphorylated compounds, with high activity for glucose-1-phosphate and glucose-6-phosphate. Optimum pH and temperature for enzyme activity were pH 5.0 and $50^{\circ}C$, respectively. Enzyme activity was stimulated by $Ca^{2+}$ and $Co^{2+}$, and inhibited by $Cu^{2+}$.

Comparative antiplasmodial activity, cytotoxicity, and phytochemical contents of Warburgia ugandensis stem bark against Aspilia africana wild and in vitro regenerated tissues

  • Denis Okello;Jeremiah Gathirwa;Alice Wanyoko;Richard Komakech;Yuseong Chung;Roggers Gang;Francis Omujal;Youngmin Kang
    • Journal of Plant Biotechnology
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    • v.50
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    • pp.97-107
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    • 2023
  • Malaria remains to be one of the most severe global public health concerns. Traditionally, Aspilia Africana and Warburgia ugandensis have been used to treat malaria in several African countries for millennia. In the current study, A. africana calli (AaC), A. africana in vitro roots (AaIR), A. africana wild leaf (AaWL), and W. ugandensis stem bark (WuSB) were dried and pulverized. Fourier transform near-infrared spectroscopy was used to analyze the powdered samples, while 80% ethanolic extracts of each sample were assayed for antiplasmodial activity (against Plasmodium falciparum strains DD2 (chloroquine-resistant) and 3D7 (chloroquine-sensitive)) and cytotoxicity. WuSB showed the highest antiplasmodial activity (IC50 = 1.57 ± 0.210 ㎍/ml and 8.92 ± 0.365 ㎍/ml against P. falciparum 3D7 and DD2, respectively) and selectivity indices (43.90 ± 7.914 and 7.543 ± 0.051 for P. falciparum 3D7 and DD2, respectively). The highest total polyphenolic contents (total phenolic and flavonoid contents of 367.9 ± 3.55 mg GAE/g and 203.9 ± 1.43 mg RUE/g, respectively) were recorded for WuSB and the lowest were recorded for AaC. The antiplasmodial activities of the tested plant tissues correlated positively with total polyphenolic content. The high selectivity indices of WuSB justify its traditional applications in treating malaria and present it as a good candidate for discovering new antimalarial compounds. We recommend elicitation treatment for AaIR, which showed moderate antiplasmodial activity against P. falciparum DD2, to increase its secondary metabolite production for optimal antimalarial activity.

Antioxidant and Antimicrobial Activity of Zostera marina L. Extract

  • Choi, Han-Gil;Lee, Ji-Hee;Park, Hyang-Ha;Sayegh, Fotoon A.Q.
    • ALGAE
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    • v.24 no.3
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    • pp.179-184
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    • 2009
  • Methanol crude extract of the sea grass Zostera marina L. and organic solvent fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were screened for antioxidant activity (total phenolic contents, DPPH scavenging activity, and reducing power) and antimicrobial activity against three human skin pathogens, two bacteria and a yeast; Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Total phenolic contents and 2, 2- diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were highest in the ethyl acetate fraction with 968.50 $\mu$g gallic acid equivalent per milligram of extract, and ca. 95% scavenging activity on the DPPH radicals at 10 mg $ml^{-1}$. In antimicrobial activity tests, MICs (Minimum Inhibitory Concentration) of each Zostera marina extract partitioned ranged from 1mg to 8 mg $ml^{-1}$ (extract/ 10% DMSO) against all three human skin pathogens. The MICs of the ethyl acetate and n-butanol fractions were the same with 1 mg $ml^{-1}$ against S. aureus and C. albicans. The ethyl acetate fraction of Z. marina does protect against free radicals and may be used to inhibit the growth of human skin pathogens.

Synthesis of Cyclic Antifreeze Glycopeptide and Glycopeptoids and Their Ice Recrystallization Inhibition Activity

  • Ahn, Mija;Murugan, Ravichandran N.;Shin, Song Yub;Kim, Eunjung;Lee, Jun Hyuck;Kim, Hak Jun;Bang, Jeong Kyu
    • Bulletin of the Korean Chemical Society
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    • v.33 no.11
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    • pp.3565-3570
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    • 2012
  • Until now, few groups reported the antifreeze activity of cyclic glycopeptides; however, the tedious synthetic procedure is not amenable to study the intensive structure activity relationship. A series of N-linked cyclic glycopeptoids and glycopeptide have been prepared to evaluate antifreeze activity as a function of peptide backbone cyclization and methyl stereochemical effect on the rigid Thr position. This study has combined the cyclization protocol with solid phase peptide synthesis and obtained significant quantities of homogeneous cyclic glycopeptide and glycopeptoids. Analysis of antifreeze activity revealed that our cyclic peptide demonstrated RI activity while cyclic glycopeptoids showed no RI activity. These results suggest that the subtle changes in conformation and Thr orientation dramatically influence RI activity of N-linked glycopeptoids.

A Potent Anti-Complementary Acylated Sterol Glucoside from Orostachys japonicus

  • Yoon, Na-Young;Min, Byung-Sun;Lee, Hyeong-Kyu;Park, Jong-Cheol;Choi, Jae-Sue
    • Archives of Pharmacal Research
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    • v.28 no.8
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    • pp.892-896
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    • 2005
  • In order to isolate substances that inhibit the hemolytic activity of human serum against eryth-rocytes, we have evaluated whole plants of the Orostachys japonicus species with regard to its anti-complement activity, and have identified its active principles following activity-guided isolation. A methanol extract of the O. japonicus, as well as its n-hexane soluble fraction, exhibited significant anti-complement activity on the complement system, which was expressed as total hemolytic activity. A bioassay-guided chromatographic separation of the constituents resulted in the isolation of three known compounds 1-3 from the active n-hexane fraction. The structure of these compounds were analyzed, and they were identified as hydroxyhopanone (1), $\beta-sitosteryl-3-O-\beta-D-glucopyranosyl-6'-O-palmitate$ (2), and $\beta-sitosteryl-3-O-\beta-D-glucopyranoside$ (3), respectively. Of these compounds, compound 2 exhibited potent anti-complement activity $(IC_{50}=1.0\pm0.1{\mu}M)$ on the classical pathway of the complement, as compared to tiliroside $(IC_{50}=76.5\pm1.1{\mu}M)$, which was used as a positive control. However, compounds 1 and 3 exhibited no activity in this system.

Gamma Radiation Induced Mutagenesis of Lysobacter enzymogenes for Enhanced Chitinolytic Activity

  • Lee, Young-Keun;Kim, Kyoung Youl;Senthilkumar, M.
    • Journal of Radiation Industry
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    • v.4 no.1
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    • pp.65-71
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    • 2010
  • Two chitinase producing strains CHI2 and CHI4 were isolated from soybean rhizosphere soil. Both the strains belonged to Lysobacter enzymogenes as indicated by 16S rDNA sequence analysis. Though strain CHI2 and CHI4 produced extracellular chitinase, they differ in their chitinolytic activity. CHI4 produced approximately three times the higher amounts of enzyme than that of CHI2 under specified conditions. CHI2 produced $535.67U\;l^{-1}$ of chitinase after 48 h incubation with a specific activity of $3.91U\;mg^{-1}$ of protein while strain CHI4 produced $1584.13U\;l^{-1}$ of chitinase with a specific activity of $10.88U\;mg^{-1}$ protein. SDS-PAGE analysis indicated that the molecular weight of chitinase enzyme was approximately 45 kDa. A faint band with a molecular weight of 55 kDa reveals the possibility for the presence of another kind of chitin binding protein. Mutant library was developed by exposing the isolates to gamma rays at their $LD_{99}$ value (0.23 kGy). Totally, 11 mutants of CHI2 and CHI4 are reported to have enhanced chitinase activity. Several leaky mutant clones with decreased enzyme activity and a defective mutant (CHI2-M16) with complete loss of chitinase activity were also identified. CHI4-M18, CHI4-M8 and CHI4-M29 showed 78.8, 41.5, and 31.9% increased chitinase activity over wild type CHI4.

Comparison of the Lower Trapezius Muscle Activity during Three Different Shoulder Flexion Exercises in Healthy Subjects

  • Hwang, Byeong-Hun;Jang, Tae-Jin;Jeon, In-Cheol
    • The Journal of Korean Physical Therapy
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    • v.34 no.1
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    • pp.6-11
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    • 2022
  • Purpose: This study investigated the muscle activity of the lower trapezius (LT) during three different shoulder flexion exercises. Methods: Twenty-three subjects between 20 and 25 years of age were enrolled. The subjects were asked to perform three different shoulder flexion exercises: 1) shoulder flexion in prone (SFP), 2) shoulder flexion in push-up with a swiss ball (SFPUS) and 3) shoulder flexion in a quadruped position with a swiss ball (SFQPS) in random order. The muscle activity of LT during each shoulder flexion exercise was measured by using surface electromyography. The muscle activity of LT was compared using one-way analysis of variance (ANOVA) and Bonferroni post hoc test among three different shoulder flexion exercises. The statistical significance level was set at α=0.01. Results: The muscle activity of LT was significantly different among three different shoulder flexion exercises (SFP, SFPUS, and SFQPS). The LT muscle activity with SFQPS exercise was greater than SFP and SFPUS exercises (p<0.01). There was no significant difference in LT muscle activity between SFP and SFPUS exercises (p>0.01). Conclusion: The LT muscle activity was greater during SFQPS than SFP and SFPUS. Therefore, SFQPS exercise can be recommended for selectively activation of LT muscle.

Activity-based Costing in Government-supported Research Institutes (정부출연연구기관에서의 활동기준 원가관리)

  • 유승억;조성표;박구선
    • Journal of Technology Innovation
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    • v.8 no.1
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    • pp.173-195
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    • 2000
  • Activity-based costing(ABC) was developed in manufacturing companies. Recently, ABC has been also applied to cost analysis in service industries and government. In this paper, ABC is applied to research institutes, especially to cost management of government-supported research institutes. ABC is an effective tool in reengineering by removing non-value-added activities, costing R&D projects, managing indirect costs and evaluating performance in research institutes. A case of activity-based costing in a government-supported institutes is provided.

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Coumarins from Angelica gigas Roots having Rat Lens Aldose Reductase Activity

  • Lee, Sang-Hyun;Jung, Sang-Hoon;Lee, Yeon-Sil;Shin, Kuk-Hyun
    • Biomolecules & Therapeutics
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    • v.10 no.2
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    • pp.85-88
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    • 2002
  • Systematic fractionation of Angelica gigas roots led to the isolation of linear coumarins such as decursinol angelate, decursin and nodakenin. These compounds were tested for their effects on rat lens aldose reductase. Nodakenin was demonstrated to exhibit significant inhibition of rat lens aldose reductase activity with $IC_{50}$ value of $7.33\Mu\textrm{M}$.

Anticoagulant Activity of Acharan Sulfate In Vivo

  • Li, Da-Wei;Choi, Hyung-Seok;Lee, In-Sun;Toida, Toshihiko;Kim, Yeong-Shik
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.216.2-216.2
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    • 2003
  • We previously reported that acharan sulfate from the African giant snail Achatina futica showed the anticoagulant activity in vitro, but it was much less than that of heparin. In present study, the anticoagulant activity of acharan sulfate was investigated in vivo. Intravenous administration of acharan sulfate prolonged the clotting time (APTT) in mice and rats in a dose-dependent manner. (omitted)

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