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Photolithographic Fabrication of Poly(Ethylene Glycol) Microstructures for Hydrogel-based Microreactors and Spatially Addressed Microarrays

  • Baek, Taek-Jin;Kim, Nam-Hyun;Choo, Jae-Bum;Lee, Eun-Kyu;Seong, Gi-Hun
    • Journal of Microbiology and Biotechnology
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    • v.17 no.11
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    • pp.1826-1832
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    • 2007
  • We describe the fabrication of poly(ethylene glycol) diacrylate (PEG-DA) hydrogel microstructures with a high aspect ratio and the use of hydrogel microstructures containing the enzyme ${\beta}$-galactosidase (${\beta}$-Gal) or glucose oxidase (GOx)/horseradish peroxidase (HRP) as biosensing components for the simultaneous detection of multiple analytes. The diameters of the hydrogel microstructures were almost the same at the top and at the bottom, indicating that no differential curing occurred through the thickness of the hydrogel microstructure. Using the hydrogel microstructures as microreactors, ${\beta}$-Gal or GOx/HRP was trapped in the hydrogel array, and the time-dependent fluorescence intensities of the hydrogel array were investigated to determine the dynamic uptake of substrates into the PEG-DA hydrogel. The time required to reach steady-state fluorescence by glucose diffusing into the hydrogel and its enzymatic reactions with GOx and HRP was half the time required for resorufin ${\beta}$-D-galactopyranoside (RGB) when used as the substrate for ${\beta}$-Gal. Spatially addressed hydrogel microarrays containing different enzymes were micropatterned for the simultaneous detection of multiple analytes, and glucose and RGB solutions were incubated as substrates. These results indicate that there was no cross-talk between the ${\beta}$-Gal-immobilizing hydrogel micropatches and the GOx/HRP-immobilizing micropatches.

Isolation and Characterization of Thermostable Xylanase-producing Paenibacillus sp. DG-22. (내열성 Xylanase를 생산하는 Paenibacillus sp. DG-22 균주의 분리 및 효소 특성)

    • Microbiology and Biotechnology Letters
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    • v.32 no.1
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    • pp.22-28
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    • 2004
  • A new moderate thermophilic bacterial strain DG-22 which produces thermostable xylanase was isolated from a timber yard soil in Kyungju, Korea. On the basis of morphological, biochemical and phylogenetic studies the new isolate was identified as a Paenibacillus species. Production of xylanase in this strain was strongly induced by adding xylan to the growth medium and repressed by glucose or xylose. No cellulase activity was detected. The temperature and pH for optimum activity were 8$0^{\circ}C$ and 5.0-5.5, respectively. The crude xylanase was stable at $60^{\circ}C$ and retained 60% of initial activity after 2h at $70^{\circ}C$. Zymogram analysis of the culture supernatant showed two xylanase active bands with molecular masses of 22 and 30 kDa.

A study on the characteristics of corrosion-fatigue-crack propagation in the welded parts of high tensile steels under sea water (고장력강 용접부의 해수중 부식피로균열 성장특성에 관한 연구)

  • 김영식;박무창
    • Journal of Ocean Engineering and Technology
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    • v.1 no.2
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    • pp.113-122
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    • 1987
  • Ships and offshore strrctures are exposed to the corrosive surroundings, and the extablishment of the design criteria and the elucidation on the influence by this environment are requested to maintain the safety and to demonstrate the function of the structure. In this paper, the fatigue-crack-growth behavior on the compact tension specimens of quenched, tempered HT80 grade steels and RA36 high tensile steels having a single edge fatigue cracked notch respectively, were investigated under the repeated tensile stress with constant stroke in sea water for the welded parts by shielded metal arc welding. Main results obtained are summerized as follows; 1. The fatigue-crack-growth rates da/dN in sea water appeared to be greater behavior than those in air environment at the same stress intensisy factor range $\DeltaK$. 2. The correlation data of da/dN$\DeltaK$ of the two kinds of high tensile steels in sea water showed no great difference, however, the correlation data of da/dN$\DeltaK/\sigma_y$($\sigma_y$ stands for yield strength of the material) showed that the fatigue-crack-growth behavior of RA36 plate is affected by active path corrosion(APC) mechanism, while that of HT80 grade plate is mainly affected by hydrogen embrittlement mechanism.

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Cloning and Immunological Characterization of the 84-kDa Heat Shock Protein, ClpL, in Streptococcus pneumoniae (84-kDa의 폐렴구균 열충격단백질 ClpL의 Cloning 및 면역특성에 관한 연구)

  • 권혁영;김용환;최혜진;박연진;표석능;이동권
    • Biomolecules & Therapeutics
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    • v.9 no.2
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    • pp.79-87
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    • 2001
  • Heat shock proteins serve as chaperone by preventing the aggregation of denatured proteins and promote survival of pathogens in harsh environments. In this study, heat shock gene encoding a 84-kDa (p84) protein, which is one of the three major heat shock proteins in S. pneumoniae, was cloned and characterized. PCR with a forward primer derived from N-terminal amino acid sequence of the p84 and a reverse primer derived from the conserved second ATP-binding region of Clp family was used for amplification of the gene encoding the p84 and subsequently the PCR product was used for sequence determination. Sequence analysis of the p84 gene demonstrated that it is a member of ClpL. The deduced amino acid sequence of pneumococcal ClpL shows homology with other members of the Clp family, and particularly, even in variable leader region, with bovine Clp-like protein and L. lactis ClpL. S. pneumoniae clpL is the smallest clop member (701 amono acids) containing the two conserved ATP-binding regions, and hydrophilic N-terminal variable region of pneu-mococcal Clp ATPase is much shorter than any known Clp ATPases. Histidine tagged ClpL was overexpressed and purified from E. coli. Immunoblot analysis employing antisera raised against pneumococcus p84 demonstrated no cross-reactivity with Clp analog in Eschericha coli, Staphylococcus aureus and human HeLa cells. Preimmunization of mice with ClpL extended mice life partially but did not protect them from death.

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Differential expression of the 27 kDa cathepsin L-like cysteine protease in developmental stages of Spirometra erinacei

  • Kong, Yoon;Yun, Doo-Hee;Cho, Seung-Yull;Sohn, Woon-Mok;Chung, Young-Bae;Kang, Shin-Yong
    • Parasites, Hosts and Diseases
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    • v.38 no.3
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    • pp.195-199
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    • 2000
  • The 27 kDa cathepsin L-like cysteine protease of Spirometra erinocei plerocercoid is known to play an important function in tissue penetration, nutrient uptake and immune modulation in human sparganosis. In the present study, the expression of this enzyme was examined at different developmental stages of S. erinacei including immature egg, coracidium, plerocercoid in tadpole and rat, and adult Proteolytic activity against carboxybenzoyl-phenylalanyl-arginyl-7-amino-4-rnethylcournarin was do tooted in the extracts of coracidia and plerocercoid while no activity was observed in those of immature egg and adult. The specific activity in coraridial extracts was lower than that in the plerocercoid. Reverse transcription-polymerase chain reaction and Northern biol analysis demonstrated that the gene was expressed in the coracidium and plerocercoid but not in immature egg and adult. These results suggest that the 27 kDa cysteine protease is only expressed in the stages involving active migration of the parasite in the host tissue.

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Molecular Identification of Cryptosporidium viatorum Infection in a Patient Suffering from Unusual Cryptosporidiosis in West Bengal, India

  • Sardar, Sanjib Kumar;Ghosal, Ajanta;Saito-Nakano, Yumiko;Dutta, Shanta;Nozaki, Tomoyoshi;Ganguly, Sandipan
    • Parasites, Hosts and Diseases
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    • v.59 no.4
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    • pp.409-413
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    • 2021
  • In this study, we have collected and screened a total of 268 stool samples from diarrheal patients admitted to an Infectious disease hospital in Kolkata for the presence of Cryptosporidium spp. The initial diagnosis was carried out by microscopy followed by genus specific polymerase chain reaction assays based on 70 kDa heat shock proteins (HSP70). DNA sequencing of the amplified locus has been employed for determination of genetic diversity of the local isolates. Out of 268 collected samples, 12 (4.48%) were positive for Cryptosporidium spp. Sequences analysis of 70 kDa heat shock proteins locus in 12 Cryptosporidium local isolates revealed that 2.24% and 1.86% of samples were showing 99% to 100% identity with C. parvum and C. hominis. Along with the other 2 major species one recently described globally distributed pathogenic species Cryptosporidium viatorum has been identified. The HSP70 locus sequence of the isolate showed 100% similarity with a previously described isolate of C. viatorum (Accession No. JX978274.1, JX978273.1, and JN846706.1) present in GenBank.

Effect of Bio-logger Attachment Location on Blood Characteristics and Bio-logger Attachment Efficiency in Spotted Sea Bass Lateolabrax maculatus (바이오로거 부착 위치가 점농어(Lateolabrax maculatus)의 혈액 성상 및 바이오로거 부착효율에 미치는 영향)

  • Sung-Yong Oh
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.56 no.5
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    • pp.651-659
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    • 2023
  • The effect of bio-logger tagging location on blood characteristics and bio-logger attachment efficiency in spotted sea bass (mean body weight 2356.7 g) was investigated. The fish were tagged at four different tagging locations: no-tag (control), operculum attachment (OA), dorsal muscle attachment (DA), and cauda peduncle muscle attachment (CA). The blood properties and bio-logger attachment efficiencies were examined on days 1, 7, 14, and 35 after tagging the bio-logger at each tagging location. During the experimental periods, the concentrations of hematocrit and hemoglobin in whole blood, and GOT (glutamic oxaloacetic transaminase), GPT (glutamic pyruvic transaminase), total protein (TP), glucose, total cholesterol, cortisol, and superoxide dismutase in plasma were not affected by the attachment location of the bio-logger, however, the TP concentration was significantly lower in OA than in the control group on day 7. After tagging for 35 days, the efficiencies of bio-logger attachment in the OA, DA, and CA after tagging for 35 days were 33.3%, 100.0%, and 33.3%, respectively. These results indicate that, in our experimental condition, the most appropriate bio-logger attachment location is DA, providing basic information on bio-logger utilization methods for ecological and biological biotelemetry surveys of the spotted sea bass.