• Journal of fish pathology
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• v.28 no.1
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• pp.43-51
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• 2015

The pharmacokinetic properties and residue levels of amoxicillin (AMOX) were studied after intramuscular injection to cultured olive flounders ($100{\pm}50g$), Paralichthys olivaceus. For pharmacokinetic studies, AMOX of 20 to 80 mg/kg body weight was administered at $17{\pm}2^{\circ}C$ or $22{\pm}2^{\circ}C$ and AMOX concentrations were determined in plasma, the liver, and the kidney by HPLC-UVD. Plasma samples were assessed at 0.25, 0.5, 1, 3, 6, 12, 24, 48, 72, 96, 168 hours post-dose, whereas liver and kidney concentrations were measured at 0.25 to 48 hours post-dose. The kinetic profiles of AMOX were analyzed by fitting to a 2-compartmental model with PKSolver program. The following parameters were obtained for a single dosage of 20, 40 and 80 mg/kg of body weight at $22^{\circ}C$ and 20 and 40 mg/kg of body weight at $17^{\circ}C$ in plasma, liver and kidney, respectively: $C_{max}$ (the peak concentration)= $27.23-257.36{\mu}g/m{\ell}$, $5.49-41.65{\mu}g/g$, $16.75-129.31{\mu}g/g$; $t_{max}$ (the time for peak concentration)= 0.05-0.91, 1.36-3.28, 1.95-4.49 h. For residue studies, AMOX of 40 and 400mg/kg was administered, and muscle samples were taken at 2, 5, 7, 14 and 21 days post-dose. The residueof AMOX in the muscle were found under the MRLs (maximum residue levels) within 7 days for the two doses.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.459-463
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• 2015

This study evaluated the microbial conversion of coconut oil waste, a major agro-residue in tropical countries, into single cell oil (SCO) feedstock for biodiesel production. Copra cake was used as a low-cost renewable substrate without any prior chemical or enzymatic pretreatment for submerged growth of an oleaginous tropical mangrove fungus, Aspergillus terreus IBB M1. The SCO extracted from fermented biomass was converted into fatty acid methyl esters (FAMEs) by transesterification and evaluated on the basis of fatty acid profiles and key fuel properties for biodiesel. The fungus produced a biomass (8.2 g/l) yielding 257 mg/g copra cake SCO with ~98% FAMEs. The FAMEs were mainly composed of saturated methyl esters (61.2%) of medium-chain fatty acids (C12-C18) with methyl oleate (C18:1; 16.57%) and methyl linoleate (C18:2; 19.97%) making up the unsaturated content. A higher content of both saturated FAMEs and methyl oleate along with the absence of polyunsaturated FAMEs with ≥4 double bonds is expected to impart good fuel quality. This was evident from the predicted and experimentally determined key fuel properties of FAMEs (density, kinematic viscosity, iodine value, acid number, cetane number), which were in accordance with the international (ASTM D6751, EN 14214) and national (IS 15607) biodiesel standards, suggesting their suitability as a biodiesel fuel. The low cost, renewable nature, and easy availability of copra cake, its conversion into SCO without any thermochemical pretreatment, and pelleted fungal growth facilitating easier downstream processing by simple filtration make this process cost effective and environmentally favorable.

• Korean Journal of Clinical Pharmacy
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• v.15 no.1
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• pp.46-49
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• 2005

A simple HPLC method was employed for the determination of pentoxifylline in human serum. After addition of internal standard (IS, 50 uL of 3 ug/mL chloramphenicol methanol solution) into the serum sample, the drug and IS were extracted by dichloromethane. Following a 1-min vortex-mixing and a 15-min centrifugation at 3500 게m, the organic phase was transferred and evaporated to dryness under a vacuum. The residue was reconstituted with 120 ${\mu}L$ of mobile phase and 50 ${\mu}L$ was injected into C18 column with a mobile phase composed of 0.034 M phosphoric acid adjusted to pH 4 with 10 M NaOH and acetonitrile (75:25, v/v). The samples were detected using an ultraviolet detector at 273 nm. The method was simple, specific and validated with a limit of 10 ng/mL. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was evaluated by analysis of human serum after oral administration of a single 400 mg dose to 8 healthy subjects. The pharmacokinetic parameters for pentoxifylline in human subjects were calculated using WinNonlin program. As a result, $AUC_{t},\;C_{max},\;T_{max}$ and $t_{1/2}$ were $962.28{\pm}645.69\;ng{\cdot}/mL$, $132.82{\pm}42.05$ ng/mL, $2.06{\pm}2.68$ hr and $8.74{\pm}4.38$ hr, respectively. Based on the results, this validated method appears to be useful fur the pharmnacokinetic study of pentoxifylline in humans.

• Mass Spectrometry Letters
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• v.3 no.1
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• pp.10-14
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• 2012

Artificially oxidized cysteine residues in peroxiredoxin 6 (Prx6) were detected by electrospray interface capillary liquid chromatography-linear ion trap mass spectrometry after the preparation of two-dimensional gel electrophoresis (2D-GE). We used Prx6 as a model protein because it possesses only two cysteine residues at the 47th and 91st positions. The spot of Prx6 on 2D-GE undergoes a basic (isoelectric point, pI 6.6) to acidic (pI 6.2) shift by exposure to peroxide due to selective overoxidation of the active-site cysteine Cys-47 but not of Cys-91. However, we detected a tryptic peptide containing cysteine sulfonic acid at the 47th position from the basic spot and a peptide containing both oxidized Cys-47 and oxidized Cys-91 from the acidic spot of Prx6 after the separation by 2D-GE. We prepared two types of oxidized Prx6s: carrying oxidized Cys-47 (single oxidized Prx6), and other carrying both oxidized Cys-47 and Cys-91 (double oxidized Prx6). Using these oxidized Prx6s, the single oxidized Prx6 and double oxidized Prx6 migrated to pIs at 6.2 and 5.9, respectively. These results suggest that oxidized Cys-47 from the basic spot and oxidized Cys-91 from the acidic spot are generated by artificial oxidation during sample handling processes after isoelectric focusing of 2D-GE. Therefore, it is important to make sure of the origin of cysteine oxidation, if it is physiological or artificial, when an oxidized cysteine residue(s) is identified.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.470-477
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• 1995

Flavonoids from Scutellariae Radix possessed a dual function both as an anti-inflammatory agent and an enhancer of cellular activity in gingival fibroblast. The purpose of this study was to evaluate on the toxicity of ethanolic extract from the root of Scutellariae Radix Georgi and its flavonoids, Wogonin, Baicalein, and Baicalin were isolated and purified by the following method. The crude drug was extracted with ethyl acetate and the residue was dissolved in ethyl alcohol. The ethyl alcohol soluble fraction was separated, concentrated, and then chromatographed on a silica gel column. The acute oral LD 50 in rats was determined for EtOH ex. of Scutellariae Radix and three compounds were evaluated with a single oral gavage at three graded dosage levels. The acute intravenous LD 50 was determined with a single intravenous injection via the jugular vein at three graded dosage levels. Groups of 5 male and 5 female rats, 6 week of age at the start of the study, were fed diets containing 3 graded dosage levels for 14 days. Groups of 5 male and 5 female hamster received O.5ml of the test article at once in a day for 5 days to the buccal cheek pouch for two minutes each. The acute oral LD50 for EtOH ex. of Scutellariae Radix is 1430mg/kg, and for Wogonin 1320mg/kg, for Baicalein 1250mg/kg, for Baicalin 1330mg/kg. The acute intravenous toxicity of EtOH ex. of Scutellariae Radix and its extracts was found to be 27mg/kg body weight No toxic effects were observed in rats fed up to 200mg/kg of EtOH ex. of Scutellariae Radix, Wogonin, Baicalein and Baicalin in the diet for 14 days. The acute Mucouse Membrane LD 50 in hamsters was found to be greater than 100mg/kg. These results suggested that EtOH ex. of Scutellariae Radix and its flavonoids are safe for oral care products using limited amount of extract.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.389-394
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• 2006

Fragmentation efficiencies of various ‘activated-ion’ electron capture dissociation (AI-ECD) methods are compared for a model system of bovine ubiquitin 7+ cations. In AI-ECD studies, sufficient internal energy was given to protein cations prior to ECD application using IR laser radiation, collisions, blackbody radiation, or in-beam collisions, in turn. The added energy was utilized in increasing the population of the precursor ions with less intra-molecular noncovalent bonds or enhancing thermal fluctuations of the protein cations. Removal of noncovalent bonds resulted in extended structures, which are ECD friendly. Under their best conditions, a variety of activation methods showed a similar effectiveness in ECD fragmentation. In terms of the number of fragmented inter-residue bonds, IR laser/blackbody infrared radiation and ‘in-beam’ activation were almost equally efficient with ~70% sequence coverage, while collisions were less productive. In particular, ‘in-beam’ activation showed an excellent effectiveness in characterizing a pre-fractionated single kind of protein species. However, its inherent procedure did not allow for isolation of the protein cations of interest.

• BMB Reports
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• v.30 no.3
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• pp.222-228
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• 1997

Protein phosphatase 2C (PP2C) is one of the four major serine/threonine phosphatases which is dependent on $Mg^{2+}$ for its activity. PP2C was purified from rat liver cytosol and its characteristics were investigated. The substrate employed for routine assay was $[^{32}P]casein$ phosphorylated by PKA. The purification process involved DEAE chromatography, ammonium sulfate fractionation, phenyl sepharose chromatography, sephacryl 5-200 gel filtration, and histone agarose chromatography. The SDS-PAGE of PP2C showed one major single protein band at a position corresponding to a molecular mass of 43 kd and the purification fold was 637. The enzyme showed a pH optimum of 8 and $K_M$ value was $1.9\;{\mu}M$. However, when the substrate was changed to $[^{32}P]histone$, the pH optimum was shifted to 7 and $K_M$ value was $2.3\;{\mu}M.\;Mg^{2+}$ was essential to the enzyme activity and okadaic acid did not exert any inhibitory effect on the enzyme. To examine residue in the active site of PP2C effects of some protein-modifying reagents were tested.

• BMB Reports
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• v.42 no.12
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• pp.812-816
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• 2009

To screen chaperone proteins from Schizosaccharomyce pombe (S. pombe), we prepared recombinant citrate synthase of the fission yeast as a substrate of anti-aggregation assay. Purified recombinant citrate synthase showed citrate synthase activity and was suitable for the substrate of chaperone assay. Several heat stable proteins including aspartyl aminopeptidase (AAP) for candidates of chaperone were screened from the supernatant fraction of heat-treated crude extract of S. pombe. The purified AAP migrated as a single band of 47 kDa on SDS-polyacrylamide gel electrophoresis. The native size of AAP was estimated as 200 kDa by a HPLC gel permeation chromatography. This enzyme can remove the aspartyl residue at N-terminus of angiotensin I. In addition, AAP showed the heat stability and protected the aggregation of citrate synthase caused by thermal denaturation. This study showed that S. pombe AAP is a moonlight protein that has aspartyl aminopeptidase and chaperone activities.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1038-1046
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• 2008

This study was carried out to develop a small-sized biosensor based on surface plasmon resonance (SPR) for the rapid identification of insecticide residues for food safety. The SPR biosensor module consists of a single 770 nm-light emitting diodes (LED) light source, several optical lenses for transferring light, a hemisphere sensor chip, photo detector, A/D converter, power source, and software for signal processing using a computer. Except for the computer, the size and weight of the sensor module are 150 (L)$\times$70 (W)$\times$120 (H) mm and 828 g, respectively. Validation and application procedures were designed to assess refractive index analysis, affinity properties, sensitivity, linearity, limits of detection, and robustness which includes an analysis of baseline stability and reproducibility of ligand immobilization using carbamate (carbofuran and carbaryl) and organophosphate (cadusafos, ethoprofos, and chlorpyrifos) insecticide residues. With direct binding analysis, insecticide residues were detected at less than the minimum 0.01 ppm and analyzed in less than 100 sec with a good linear relationship. Based on these results, we find that the binding interaction with active target groups in enzymes using the miniaturized SPR biosensor could detect low concentrations which satisfy the maximum residue limits for pesticide tolerance in Korea, Japan, and the USA.

• Parasites, Hosts and Diseases
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• v.40 no.3
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• pp.131-138
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• 2002

The cyclophilins (Cyps) are family members of proteins that exhibit peptidylprolyl cis-trans isomerase (PPIase, EC 5.2.1.8) activity and bind the immunosuppressive agent cyclosprin A (CsA) in varying degrees. During the process of random sequencing of a cDNA library made from Giardia intestinalis WB strain, the cyclophilin gene (gicypl) was isolated. An open reading frame of gicyp1 gene was 576 nucleotides, which corresponded to a translation product of 176 amino acids (Gicypl). The identity with other Cyps was about 58-71%. The 13 residues that constituted the CsA binding site of human cyclophilin were also detected in the amino acid sequence of Gicypl, including tryptophan residue essential for the drug binding. The single copy of the gicypl gene was detected in the G. intestinalis chromosome by southern hybridization analysis. Recombinant Gicyp 1 protein clearly accelerated the rate of cis ${\rightarrow}$ trans isomerization of the peptide substrate and the catalysis was completely inhibited by the addition of $0.5{\;}{\mu}M$ CsA.