• Title/Summary/Keyword: pH sensitive

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Characterization of a Vibrio parahaemolyticus Phage Isolated from Marine (해양에서 분리한 Vibrio parahaemolyticus Phage의 특성)

  • Yoon, Sun-Ok;Ju, Seong-A;Heo, Moon-Soo;Jung, Cho-Rok;Ju, Jin-Woo
    • The Journal of the Korean Society for Microbiology
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    • v.34 no.5
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    • pp.423-433
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    • 1999
  • A novel bacteriophage, designated as VPP97, that infects the strains of Vibiro parahaemolyticus (hallophilic, Gram-negative bacterium) isolated most commonly from marine environments, has been discovered, and several of its properties have been determined. The plaques were clear and sized $0.6{\sim}1.0\;mm$ in diameter. The virion forms a single band on 70% sucrose gradient and ${\rho}1.50$ CsCl gradient by sucrose gradient centrifugation and CsCl gradient centrifugation respectively. It has a hexagonal head and a relatively long tail, as shown by electron microscopy. Vibrio alginolyticus, Vibrio fluvialis and Vibrio furnissii were also sensitive to this phage. It was almost totally inactivated at $70^{\circ}C$ and at pH below 5 or over 10. The nucleic acid of VPP97 is composed of DNA. The VPP97 had 9 specific structural proteins sized between 21.5 kDa and 97.4 kDa on SDS-PAGE. When V. parahaemolyticus cultures were treated with either phage VPP97 or one of the several antibiotics for 2 hours, the viable number of V. parahaemolyticus treated with the phage VPP97 is lower than that treated with chloramphenicol, erythromycin or penicillin, but not lower than that treated with tetracycline. Mice that have responded to the phage treatment revealed the lower numbers of V. parahaemolyticus in small intestine and less damage on small intestine compared to the untreated mice. Therefore, we suggest that the phage treatment appears effective to the infection by V. parahaemolyticus.

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Detection and Characterization of Novel Extracellular Phospholipase $A_2$ in Urine of Patients with Acute Pyelonephritis

  • Park, Jae-Hyeun;Lee, Jee-Hye;Baek, Suk-Hwan;Moon, Tae-Chul;Lee, Jong-Myung;Kim, Nung-Soo;Nam, Kyung-Soo;Chang, Hyeun-Wook
    • BMB Reports
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    • v.30 no.2
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    • pp.101-105
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    • 1997
  • Extracellular phospholipase $A_2$ activity has been detected in urine of patients with acute pyelonephritis (APN). This enzyme required micromolar $Ca^{2+}$ ion for its maximum activity and showed a broad range of pH (4.5~10) optimum. Urine enzyme hydrolyzed phosphatidylethanolamine (PE) and phosphatidylserine (PS) more effectively than phosphatidylcholine (PC). $PLA_2$ activity in the urine of patients with APN was about 5-fold higher than that of healthy individuals. When urine was subjected to heparinSepharose column chromatography, phospholipase $A_2$ activity was detected in both heparin-non-binding and binding fractions. Both phospholipase $A_2$ activities were sensitive less than a micromolar calcium concentration and did not react with anti-human 14-kDa group II phospholipase $A_2$ monoclonal antibody, HP-l. These findings suggest that two kinds of novel extracellular phospholipase $A_2$. which may not belong to the 14-kDa group II phospholipase $A_2$ family, exist in the urine of patients with APN.

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Effects of frequency ratio on bridge aerodynamics determined by free-decay sectional model tests

  • Qin, X.R.;Kwok, K.C.S.;Fok, C.H.;Hitchcock, P.A.
    • Wind and Structures
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    • v.12 no.5
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    • pp.413-424
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    • 2009
  • A series of wind tunnel free-decay sectional model dynamic tests were conducted to examine the effects of torsional-to-vertical natural frequency ratio of 2DOF bridge dynamic systems on the aerodynamic and dynamic properties of bridge decks. The natural frequency ratios tested were around 2.2:1 and 1.2:1 respectively, with the fundamental vertical natural frequency of the system held constant for all the tests. Three 2.9 m long twin-deck bridge sectional models, with a zero, 16% (intermediate gap) and 35% (large gap) gap-to-width ratio, respectively, were tested to determine whether the effects of frequency ratio are dependent on bridge deck cross-section shapes. The results of wind tunnel tests suggest that for the model with a zero gap-width, a model to approximate a thin flat plate, the flutter derivatives, and consequently the aerodynamic forces, are relatively independent of the torsional-to-vertical frequency ratio for a relatively large range of reduced wind velocities, while for the models with an intermediate gap-width (around 16%) and a large gap-width (around 35%), some of the flutter derivatives, and therefore the aerodynamic forces, are evidently dependent on the frequency ratio for most of the tested reduced velocities. A comparison of the modal damping ratios also suggests that the torsional damping ratio is much more sensitive to the frequency ratio, especially for the two models with nonzero gap (16% and 35% gap-width). The test results clearly show that the effects of the frequency ratio on the flutter derivatives and the aerodynamic forces were dependent on the aerodynamic cross-section shape of the bridge deck.

Study on the Spectrophotometric Determination of Rare Earth by Ternary Complex Using Xylenol Orange and Surfactant (Xylenol Orange와 계면활성제의 삼성분 착물에 의한 희토류원소의 분광광도법 정량에 관한 연구)

  • Cha, Ki-Won;Park, Chan-Il;Kang, Sun-Hee;Chang, Byung-Du
    • Analytical Science and Technology
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    • v.7 no.3
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    • pp.277-284
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    • 1994
  • The spectrophotometric determination of rare earth elements with XO was investigated in the presence of cetylpyridium chloride(CPC), dodecyltrimethylammonium bromide(DTMAB), cetyltrimetylammonium bromide (CTMAB), Triton X-100 at pH 6.2. The complex between XO and rare earth elements in the presence of cationic surfactants was very stable and more sensitive than in the absence of surfactants. The largest absorbance increase was provided by CTMAB, which was therefore chosen for determination of rare earth elements. REE-XO-CTMAB complex has absorption maxima at 618nm and obeys the Beer's law in the range of 0~0.5 ppm. Molar absorptivity was $1.5{\times}10^5mol^{-1}cm^{-1}l$.

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Simultaneous determination of fluorometholone and tetrahydrozoline hydrochloride in ophthalmic suspension by HPLC

  • Pham, Thuy-Vy;Mai, Xuan-Lan;Song, Ha-Ram;Ahn, Soo-Bin;Cha, Min-Jeong;Kang, Jong-Seong;Woo, Mi Hee;Na, Dong-Hee;Chun, In-Koo;Kim, Kyeong Ho
    • Analytical Science and Technology
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    • v.31 no.2
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    • pp.88-95
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    • 2018
  • A simple, sensitive, and selective high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous quantification of fluorometholone (FLU) and tetrahydrozoline hydrochloride (THZ) in combined ophthalmic formulations. The effects of several factors, including detection wavelength, buffer pH, buffer concentration, and organic solvent concentration, on the performance of the method were investigated. The performance of the developed method was validated in accordance with the requirements of the International Conference on Harmonization. The linearity of the calibration curves in the desired concentration range was high for both FLU and THZ ($r^2=0.9999$). The accuracy and precision of the method were determined by a recovery study at analyte concentrations of 80 %, 100 %, and 120 %. The recovery was 99.60-100.17 % for both analytes, with a relative standard deviation less than 1.0 % at any concentration level. The validated results indicate that the new HPLC method could be successfully applied for the simultaneous determination of FLU and THZ in ophthalmic suspensions.

Pharmacokinetic Analysis of Montelukast in Healthy Korean Volunteers by High Performance Liquid Chromatography-Tandem Mass Spectrometry

  • Jo, Min-Ho;Park, Mi-Sun;Seo, Ji-Hyung;Shim, Wang-Seob;Yim, Sung-Vin;Lee, Kyung-Tae
    • Journal of Pharmaceutical Investigation
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    • v.41 no.5
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    • pp.289-294
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    • 2011
  • A rapid and specific high performance liquid chromatography-tandem mass (LC/MS/MS) method for the analysis of montelukast in human plasma has been developed and validated. After cold acetonitrile-induced precipitation of the plasma samples, montelukast and glipizide (internal standard, IS) were eluted on a reverse-phase $C_{18}$ column by isocratic mobile phase consisted of 10 mM ammonium formate buffer (adjusted to pH 3.5 with formic acid) and acetonitrile (3:97, v/v). Acquisition was performed with multiple reaction monitoring (MRM) mode by monitoring the transitions: m/z 587.2${\rightarrow}$ 423.2 for montelukast and m/z 446.0${\rightarrow}$321.2 for IS. Ranges of concentration for calibration curves (10-1000 ng/mL) showed correlation coefficients ($r^2$) were better than 0.9948. Precision of intra- and inter-day ranged from 3.70 to 11.68% and from 3.04 to 12.95%, accuracy of intra-day and inter-day ranged from 93.34 to 102.75% and from 100.79 to 107.63%, respectively. The described method provides a fast and sensitive analytical tool for determining montelukast levels in plasma, and was successfully applied to a pharmacokinetic study in 16 healthy human subjects after oral administration of 10mg tablet formulation of montelukast sodium under fasting conditions.

Effects of enzymatic hydrolysis of buckwheat protein on antigenicity and allergenicity

  • Sung, Dong-Eun;Lee, Jeongok;Han, Youngshin;Shon, Dong-Hwa;Ahn, Kangmo;Oh, Sangsuk;Do, Jeong-Ryong
    • Nutrition Research and Practice
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    • v.8 no.3
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    • pp.278-283
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    • 2014
  • BACKGROUND/OBJECTIVES: Due to its beneficial health effects, use of buckwheat has shown a continuous increase, and concerns regarding the allergic property of buckwheat have also increased. This study was conducted for evaluation of the hydrolytic effects of seven commercial proteases on buckwheat allergens and its allergenicity. MATERIALS/METHODS: Extracted buckwheat protein was hydrolyzed by seven proteolytic enzymes at individual optimum temperature and pH for four hours. Analysis was then performed using SDS-PAGE, immunoblotting, and competitive inhibition ELISA (ciELISA) with rabbit antiserum to buckwheat protein, and direct ELISA with pooled serum of 21 buckwheat-sensitive patients. RESULTS: Alkaline protease, classified as serine peptidase, was most effective in reducing allergenicity of buckwheat protein. It caused decomposition of the whole buckwheat protein, as shown on SDS-PAGE, and results of immunoblotting showed that the rabbit antiserum to buckwheat protein no longer recognized it as an antigen. Allergenicity showed a decrease of more than 50% when pooled serum of patients was used in ELISA. Two proteolytic enzymes from Aspergillus sp. could not hydrolyze buckwheat allergens effectively, and the allergenicity even appeared to increase. CONCLUSIONS: Serine-type peptidases appeared to show a relatively effective reduction of buckwheat allergenicity. However, the antigenicity measured using rabbit antiserum did not correspond to the allergenicity measured using sera from human patients. Production of less allergenic buckwheat protein may be possible using enzymatic hydrolysis.

Simultaneous determination of four fluoroquinolones in chicken, pork and beef edible muscle by HPLC (식육 중 항균물질 (플루오르퀴놀론계) 동시 다성분 분석법 개선 연구)

  • Park Dong-Yeob;Hwang Bo-Won;Cho Sung-Suk;Choi Chan-Young;Cho Sang-Lae;Park Ae-Ra;Jung Eun-Hee;Byun You-Sung
    • Korean Journal of Veterinary Service
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    • v.29 no.2
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    • pp.111-122
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    • 2006
  • A direct, accurate and sensitive chromatographic analytical method for quantitative determination of four fluoroquinolones (norfloxacin, cirprofloxacin, danofloxacin and enrofloxacin) in chicken, pork and beef edible muscle is proposed in the present study. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. The samples were homogenized and the antimicrobials were added, then they were extracted twice with dichloromethane. Fluoroquinolone antibiotics were separated on an agilent $250x4mm,\;C_{18},\;5{\mu}m$, analytical column, at $25^{\circ}C$. The mobile phase consisted of a mixture of DW : acetonitrile : triethylamine(80:19:1%, v/v, pH 3.0) leading to retention times less than 14 min. at a flow rate 0.5 ml/min. These fluoroquinolones were detected by liquid chromatography with fluorescence at 290 nm excitation and 465 nm emission. The limits of quantification in each edible muscle (chicken, pork, and beef) were 0.32-6.54 ng/g. Using 0.5 g of each sample, average recovery rates at fortification levels of 0.05, 0.1 and 0.2 ${\mu}g/ml$ ranged 70.14-71.71% for NFX, 71.87-73.89% for CFX, 82.16-92.35% for DFX, and 90.13-98.12 for EFX This is a simple and economic method to quantify the presence of NFX, CFX, EFX and DFX in edible muscle of animal origin.

Role of the Neutrophil-to-Lymphocyte Ratio at the Time of Arrival at the Emergency Room as a Predictor of Rhabdomyolysis in Severe Trauma Patients

  • Bae, Jin Chul;Sun, Kyung Hoon;Park, Yong Jin
    • Journal of Trauma and Injury
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    • v.33 no.2
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    • pp.96-103
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    • 2020
  • Purpose: In patients with trauma, rhabdomyolysis (RM) can lead to fatal complications resulting from muscle damage. Thus, RM must be immediately diagnosed and treated to prevent complications. Creatine kinase (CK) is the most sensitive marker for diagnosing RM. However, relying on CK tests may result in delayed treatment, as it takes approximately 1 hour to obtain CK blood test results. Hence, this study investigated whether the neutrophil-to-lymphocyte ratio (NLR) could predict RM at an earlier time point in patients with trauma, since NLR results can be obtained within 10 minutes. Methods: This retrospective study included 130 patients with severe trauma who were admitted to the emergency room of a tertiary institution between January 2017 and April 2020. RM was defined as a CK level ≥1,000 U/L at the time of arrival. Patients with severe trauma were categorized into non-RM and RM groups, and their characteristics and blood test results were analyzed. Statistical analysis was performed using SPSS version 26.0 for Windows. Results: Of the 130 patients with severe trauma, 50 presented with RM. In the multivariate analysis, the NLR (odds ratio [OR], 1.252; 95% confidence interval [CI], 1.130-1.386), pH level (OR, 0.006; 95% CI, 0.000-0.198), presence of acute kidney injury (OR, 3.009; 95% CI, 1.140-7.941), and extremity Abbreviated Injury Scale score (OR, 1.819; 95% CI, 1.111-2.980) significantly differed between the non-RM and RM groups. A receiver operating characteristic analysis revealed that a cut-off NLR value of 3.64 was the best for predicting RM. Conclusions: In patients with trauma, the NLR at the time of arrival at the hospital is a useful biochemical marker for predicting RM.

Characterization and Methanol Biosynthesis of a Methane-Oxidizing Bacterium, Methylomonas sp. SM4, Isolated from Rice Paddy Field Soil (논에서 분리한 메탄산화세균 Methylomonas sp. SM4의 특성과 메탄올 생합성)

  • Park, Sung Min;Madhavaraj, Lavanya;Kim, Si Wouk
    • KSBB Journal
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    • v.32 no.2
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    • pp.124-132
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    • 2017
  • A methane-oxidizing bacterium was isolated from rice paddy field soil around Jeollanam-do province, Korea, and characterized. The isolate was gram-negative, orange pigmented and short rod ($1.1-1.2{\times}1.6-1.9{\mu}m$). It was catalase and urease-negative but oxidase-positive. The strain utilized methane and methanol as sole carbon and energy sources. It had an ability to grow with an optimum pH 7.0 and an optimum growth temperature $30^{\circ}C$. The strain was resistant to antibiotic polymyxin B but sensitive to streptomycin, kanamycin, ampicillin, chloramphenicol and rifampicin. The isolate required copper for their growth with concentration range of $2-25{\mu}M$, with an optimum of $10{\mu}M$. Under optimal culture condition, specific cell growth rate and generation time were found to be $0.046hr^{-1}$ and 15.13 hr, respectively. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain formed a tight phylogenetic lineage with Methylomonas koyamae with a value of 99.4% gene sequence homology. So, we named the isolate as Methylomonas sp. SM4. 8.6 mM methanol was accumulated in the reaction mixture containing 70 mM sodium formate and 40 mM $MgCl_2$ (MDH inhibitor) under atmosphere of methane:air (40:60) mixture for 24 hr at $30^{\circ}C$.