• Title/Summary/Keyword: membrane chemistry

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Effect of Protective Compounds on the Survival, Electrolyte Leakage, and Lipid Degradation of Freeze-Dried Weissella paramesenteroides LC11 During Storage

  • Yao, Amenan A.;Wathelet, Bernard;Thonart, Philippe
    • Journal of Microbiology and Biotechnology
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    • v.19 no.8
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    • pp.810-817
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    • 2009
  • The effect of cryoprotectants (maltodextrin+glycerol) and cryoprotectants+antioxidant [ascorbic acid and/or butylated hydroxytoluene (BHT)] mixtures on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage was investigated and compared with that of the control (cells without additives) over a 90-day storage period at 4 or $20^{\circ}C$ in glass tubes with water activity ($a_w$) of 0.23. The survival, electrolyte leakage, and lipid degradation were evaluated through colony counts, electrical conductivity, and thiobarbituric acid reactive substances (TBARS) content, respectively. The fatty acids composition was determined by gas chromatography, in both the total lipid extract and the polar lipid fraction, and compared with that of the control after the 90-day storage period. As the storage proceeded, increases in leakage value and TBARS content, as well as a decrease in viability, were observed. After 90 days of storage, the major fatty acids found in both the total lipid extract and the polar lipid fraction were palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids. The survival, leakage value, TBARS content and 18:2/16:0 or 18:3/16:0 ratio were the greatest for the protected strain held at $4^{\circ}C$. Cells with the cryoprotectants+BHT mixture showed the highest percentage of survival and 18:2/16:0 or 18:3/16:0 ratio in both lipid extracts, as well as the lowest leakage value and TBARS content after the 90-day storage period. Drying cells with the cryoprotectants+BHT mixture considerably slowed down polar lipid degradation and loss of membrane integrity, resulting in improved viability during storage.

Overexpression and Refolding of BACE2 (BACE2의 대량발현 및 리폴딩)

  • Park, Sun Joo;Tai, Shuaiqi;Lee, Yeon-Ji;Jeon, You-Jin;Kim, Yong-Tae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.47 no.4
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    • pp.370-375
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    • 2014
  • BACE2 is a membrane-bound aspartic protease that is highly homologous with BACE1. While BACE1 processes the amyloid precursor protein (APP) at a key step in generating ${\beta}$-amyloid peptide and presumably causes Alzheimer's disease (AD), BACE2 has not been demonstrated to be involved in APP processing directly, and its physiological functions are unknown. To determine its function and to develop inhibitors from marine sources, we constructed an overexpression vector for producing BACE2. The gene encoding human BACE2 protease was amplified using the polymerase chain reaction and cloned into the pET11a expression vector, resulting in pET11a/BACE2. Recombinant BACE2 protease was overexpressed successfully in E. coli as inclusion bodies, refolded using the rapid-dilution method, and purified via two-step fast protein liquid chromatography using Sephacryl S-300 gel filtration and Resource-Q column chromatography. The BACE2 protease produced was an active form. This study provides an efficient method not only for studying the basic properties of BACE2, but also for developing inhibitors from natural marine sources.

Screening System for Chitin Synthase II Inhibitors from Natural Resources and its Inhibitor Prodigiosin

  • Hwang, Eui-Il;Kim, Young-Kook;Lee, Hyang-Bok;Kim, Hong-Gi;Kim, Sung-Uk
    • Journal of Microbiology and Biotechnology
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    • v.10 no.2
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    • pp.251-257
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    • 2000
  • Chitin synthases are identified as key enzymes of chitin biosynthesis in most of the fungi. Among them, chitin synthase II has been reported to be and essential enzyme in chitin biosynthesis, and exists as a membrane-bound form. To search and screen new antifungal agents from natural resources to inhibit chitin synthase II, the assay conditions were established using the enzyme isolated from Saccharomyces cerevisiae ECY38-38A(pAS6) that overproduces only chitin synthase II. This enzyme was activated only by partial proteolysis with trypsin. Its actibity reached the maximum at $80{\;}\mu\textrm{g}/ml$ of trypsin and was strongly stimulated by 2.0 mM $Co^{2+}$, 1.0 nM UDP-[$^{14}C$]-GicNAc, and 32 mM free-GlcNAc. Under these assay conditions, the highest chitin synthase II activity was observed by incubation at $30^{\circ}C$ for 90 min. However, and extremely narrow range of organic solvents up to as much as 25% of DMSO and 25% of MeOH was useful for determining optimal assay conditions. After a search or potent inhibitors of chitin synthase II from natural resources, prodigiosin was isolated from Serratia marcescens and purified by solvent extration and silica gel column chromatographies. The structure of prodigiosin was determined by UV, IR, Mass spectral, and NMR spectral analyses. Its molecular weight and formula were found to be 323 and $C_{20}H_{25}N_{3}O$, respectively. Prodigiosin ingibited chitin synthase II by 50% at the concentration of $115{\;}\mu\textrm{g}/ml$.

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Lipid-binding properties of TRIM72

  • Kim, Sung-Hyen;Seo, Jeong-Hwa;Ko, Young-Gyu;Huh, Young-Duk;Park, Heon-Yong
    • BMB Reports
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    • v.45 no.1
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    • pp.26-31
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    • 2012
  • TRIM72 is known to play a critical role in skeletal muscle membrane repair. To better understand the molecular mechanisms of this protein, we carried out an in vitro binding study with TRIM72. Our study proved that TRIM72 binds various lipids with dissociation constants ($K_d$) ranging from 88.2 ${\pm}$ 9.9 nM to 550.5 ${\pm}$ 134.5 nM. In addition, the intrinsic fluorescence of TRIM72 exponentially decreased when the protein was diluted with stirring. The time-resolved fluorescence decay occurred in a concentration-independent manner. The fluorescence-decayed TRIM72 remained in its secondary structure, but its binding properties were significantly reduced. The dissociation constants ($K_d$) of fluorescence-decayed TRIM72 for palmitate and stearate were 159.1 ${\pm}$ 39.9 nM and 355.4 ${\pm}$ 106.0 nM, respectively. This study suggests that TRIM72 can be dynamically converted by various stimuli. The results of this study also provide insight into the role of TRIM72 in the repair of sarcolemma damage.

Preliminary Evaluation of the in vitro Efficacy of 1, 2-di (Quinazolin-4-yl) Diselane against SiHa Cervical Cancer Cells

  • Huang, Yin-Jiu;Zhang, Yu-Yuan;Liu, Gang;Tang, Jie;Hu, Jian-Guo;Feng, Zhen-Zhong;Liu, Fang;Wang, Qi-Yi;Li, Dan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6301-6306
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    • 2014
  • Cervical cancer is one the most common malignancies among females. In recent years, its incidence rate has shown a rising trend in some countries so that development of anticancer drugs for cervical cancer is an urgent priority. In our recent anticancer drug discovery screen, 1, 2-di (quinazolin-4-yl)diselane (LG003) was found to possess wide spectrum anticancer efficacy. In the present work, the in vitro anticancer activity of LG003 was evaluated in the SiHa cervical cancer cell line. Compared with commercial anticancer drugs 10-hydroxycamptothecin, epirubicin hydrochloride, taxol and oxaliplatin, LG003 showed better anticancer activity. Furthermore, inhibition effects were time- and dose-dependent. Morphological observation exhibited LG003 treatment results in apoptosis like shrinking and blebbing, and cell membrane damage. Lactate dehydrogenase release assay revealed that LG003 exerts such effects in SiHa cells through a physiology pathway rather than cytotoxicity, which suggests that title compound LG003 can be a potential candidate agent for cervical cancer.

One-Step Simultaneous Immunochromatographic Strip Test for Multianalysis of Ochratoxin A and Zearalenone

  • Shim, Won-Bo;Dzantiev, Boris B.;Eremin, Sergei A.;Chung, Duck-Hwa
    • Journal of Microbiology and Biotechnology
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    • v.19 no.1
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    • pp.83-92
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    • 2009
  • Individual immunochromatographic assays (ICG) for ochratoxin A (OTA) and zearalenone (ZEA) were optimized and used in the development of a one-step simultaneous immunochromatographic assay (OS-ICG) for the rapid multianalysis of two mycotoxins in corn samples. The nitrocellulose membrane of the OS-ICG was treated with OTA-bovine serum albumin (BSA), ZEA-ovalbumin (OVA), and anti-mouse IgG in the OTA test, ZEA test, and control zones, respectively. Monoclonal antibody-gold conjugates (OTA3 MAb-gold and ZEA2C5 MAb-gold) were sprayed onto the conjugate pad. The visual detection limits were 2.5 and 5 ng/ml for OTA and ZEA, respectively, and the results were obtained within 15 min after starting the analysis. An efficient, simple, and rapid extraction method using 30% MeOH/PBS was established and validated by analyzing the corn samples spiked with OTA/ZEA mixtures (0/0, 5/10, 10/20, and $20/30\;{\mu}g/kg$). The cut-off values of the OS-ICG for the spiked corn were 5 and $10\;{\mu}g/kg$ for OTA and ZEA, respectively. Natural corn samples were analyzed by OS-ICG, direct competitive enzyme-linked immunosorbent assay (DC-ELISA), and HPLC. Results of the OS-ICG were in good agreement with those obtained by DC-ELISA and HPLC. The developed OS-ICG offers a rapid, easy-to-use, and portable analytical system and can be used as a convenient qualitative tool for the on-site simultaneous determination of OTA and ZEA in cereals, food, and agricultural products in one analytical cycle.

A Case of Struvite Urolithiasis in a One-month-old Korean Sapsal Dog (1개월령 삽살개에서 발생한 Struvite요도결석 1례)

  • Oh, Won-Seok;Oh, Tae-Ho
    • Journal of Veterinary Clinics
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    • v.27 no.4
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    • pp.453-456
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    • 2010
  • A one-month-old, 0.9 kg BW, male Korean Sapsal dog with anorexia, anuria, ataxia and depression was referred. On physical examination, the dog was showed tachycardia, hypothermia and pale mucous membrane. Hematologic values showed leukocytosis and mild anemia. Serum chemistry profile results revealed increased BUN (57.3 mg/dl) and $NH_3$ ($584\;{\mu}g/dl$), decreased albumin, sodium and potassium. Urinalysis showed hematuria, proteinuria, glucosuria, bacteriuria (Staphylococcus spp.) and magnesium ammonium phosphate crystalluria. On radiographic finding, urinary bladder was enlarged and 2 mm diameter radiopaque urolith was showed between os penis and prescrotal region. Urolithiasis was surgically corrected by urethrostomy.

Research on the Correlation of the Surface Tension and Sensory Quality of Bitter Substances (쓴 맛 물질의 표면 장력과 쓴 맛의 상관 관계)

  • Kim, Jeong-Mee;Pfeilsticker, Konrad
    • Korean Journal of Food Science and Technology
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    • v.27 no.5
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    • pp.646-651
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    • 1995
  • The correlation between the bitter taste and the surface tension was found for bitter tasting, aqueous solutions. By the Szyszkowski's equation, the surface tension (STR) and taste curves (JND) were derived more clearly using the Techplot program. The specific capillary activity (log b values) for bitter tasting solutions are negatively correlated to the recognition threshold. It was shown that a more bitter substances has greater capillary activity. The correlation between the recognition threshold $(log\;C_{1})$ and the substance specific constant (a and b values) of sensory (JND) and surface tension values indicates good agreement. This means that the model of surface area adsorption in the solution/air system can apply also for the sensory model microvillus membrane in the mouth.

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Application of Three-phase Hollow Fiber LPME using an Ionic Liquid as Supported Phase for Preconcentration of Malachite Green from Water Samples with HPLC Detection

  • Zou, Yanmin;Zhang, Zhen;Shao, Xiaoling;Chen, Yao;Wu, Xiangyang;Yang, Liuqing;Zhu, Jingjing;Zhang, Dongmei
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.371-376
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    • 2014
  • A novel three-phase hollow fiber liquid phase microextraction was developed for the determination of malachite green (MG) in environmental waters, which selected [BMIM][$PF_6$] mixed with 1% trioctylphosphine oxide (TOPO) as supported phase. Several parameters (accepter phase pH, sample pH, supported phase membrane, volume of accepter phase, salinity, extraction time) that could affect extraction performance were investigated. Under the optimal extraction conditions, the established approach showed excellent characters as: high enrichment factor (212), wide linear range ($0.20-100{\mu}gL^{-1}$), low detection limit ($0.01{\mu}gL^{-1}$), good reproducibility (RSD, 8.9%, n=5) and satisfactory recovery (84.0-106.2%). The method was applied to detect MG at Yangtze River and pond waters in Zhenjiang, Jiangsu province, and 4 sites among 15 sampling sites were found MG with the concentration of $1.73-11.06{\mu}gL^{-1}$, which confirmed that the proposed environmentally friendly method was simple and effective for monitoring MG in aquatic system.

A Case of Norepinephrine Secreting Pheochromocytoma in a Dog (개에서 Norepinephrine 분비 갈색세포종 증례1)

  • Choi, Ul-Soo;Kim, Dong-Hoon;Kim, Hyun-Wook;Choi, Ji-Hye;Jang, Jae-Young
    • Journal of Veterinary Clinics
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    • v.26 no.3
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    • pp.268-272
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    • 2009
  • An-11-year-old male Shih-tzu was admitted to emergency care unit of Haemaru Referral Animal Hospital with signs of dyspnea, anuria and depression. There were abnormalities on complete blood count and serum chemistry included leukocytosis with mild left shift, mild azotemia, and increased ALT activity. Fluid therapy(0.9% saline, 40 ml/hr) and antibiotics were immediately initiated. The patient began to vomit after 5 hours' rest and pale mucous membrane, bradycardia, and hypertension were noted. Abdominal ultrasonography revealed enlarged left adrenal gland and thrombus in caudal vena cava(CVC). Result of ACTH stimulation test was normal. Cytology of ultrasound-guided FNA smears showed numerous naked nuclei, which was suggestive of adrenal medullar tumor. Concentrations of 24 hour urine metanephrine and normetanephrine was moderately increased compared to those of a control dog. Adrenal mass was surgically removed, and biopsy of the CVC mass was obtained. After surgery the patient began to recover but the dog acutely developed cardiopulmonary arrest and died. On histopathology the adrenal mass and biopsy of the CVC mass were consistent with pheochromocytoma. On electron microscopic view norepinephrine specific granules were found in the cytoplasm of tumor cells.