• Korean Journal of Materials Research
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• v.3 no.3
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• pp.272-275
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• 1993

To modify the toughness of epoxy for matrix, succinonitrile(SN) was introduced to diglycidy1 ether of bisphenol-A (DGEBA)/methylene dianiline(MDA)system. Cure reaction mdchanism of the DGEBA/MDA/SN system was strdied through Fourier transform infrared(FT-IR) spectrometry. As a result, the reaction of nitrile group of SN with secondary amine and with hydroxy1 group prevented the reaction of hydroxy1 group with epoxide group from crossoinding. Nitrile groups produced amide group by reacting with hydroxy1 groups and made a lowered crosslind density in chain networks.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1742-1750
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• 2015

Human insulin is composed of 21 amino acids of an A-chain and 30 amino acids of a B-chain. This is the protein hormone that has the role of blood sugar control. When the recombinant human proinsulin is expressed in Escherichia coli, a serious problem is the formation of an inclusion body. Therefore, the inclusion body must be denatured and refolded under chaotropic agents and suitable reductants. In this study, H27R-proinsulin was refolded from the denatured form with β-mercaptoethanol and urea. The refolding reaction was completed after 15 h at $15^{\circ}C$, whereas the reaction at $25^{\circ}C$ was faster than that at $15^{\circ}C$. The refolding yield at $15^{\circ}C$ was 17% higher than that at $25^{\circ}C$. The refolding reaction could be carried out at a high protein concentration (2 g/l) using direct refolding without sulfonation. The most economical and optimal refolding condition for human preproinsulin was 1.5 g/l protein, 10 mM glycine buffer containing 0.6 M urea, pH 10.6, and 0.3 mM β-mercaptoethanol at $15^{\circ}C$ for 16 h. The maximum refolding yield was 74.8% at $15^{\circ}C$ with 1.5 g/l protein. Moreover, the refolded preproinsulin could be converted into normal mature insulin with two enzymes. The average amount of human insulin was 138.2 g from 200 L of fermentation broth after enzyme reaction with H27R-proinsulin. The direct refolding process for H27R-proinsulin was successfully set up without sulfonation. The step yields for refolding and enzyme reaction were comparatively high. Therefore, our refolding process for production of recombinant insulin may be beneficial to the large-scale production of other biologically active proteins.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.715-718
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• 2012

The current research concerns the clinicopathological significance of MHC class I chain-related protein A (MICA) expression in oral squamous cell carcinomas (OSCCs). The expression and location of MICA protein in 14 normal oral mucous and 45 cancerous and para-cancerous tissues were assessed by immunohistochemistry and levels of MICA mRNA expression in 29 cancerous and para-cancerous tissues were determined by the real-time polymerase chain reaction. Data were analyzed with the SPSS16.0 software package. MICA was found to be located in the cytoplasm and plasma membrane. Expression was higher in para-cancerous than in cancerous tissues (P < 0.05). However, no statistical difference was found between the following: 1) para-cancerous tissue with normal mucosa; 2) normal mucosa with cancerous tissue;and 3) among different clinicopathological parameters in OSCC (P > 0.05). The level of MICA mRNA was higher in OSCCs than in para-cancerous tissues, and was correlated with the regional lymph node status and disease stage (P < 0.05). The levels of MICA protein and mRNA expression differ among normal oral mucosa, para-cancerous tissue, and cancerous tissue. MICA may contribute to the tumorigenesis and progression of OSCC.

• Elastomers and Composites
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• v.40 no.1
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• pp.3-11
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• 2005

The ruling kinetics of epoxy resins with 3 different kinds or alkenylsuccinic anhydride (ASA) having C-8, C-12, and C-16 pendant side chain length with two different catalysts was studied by using differential scanning calorimetry (DSC). Nonisothermal and isoconversional method has been used for characterizing the effect of the pendant side chain length in the curing process. Results or nonisothermal method showed that there was no significant difference in the effect of the pendant side chain length of ASA. But isoconversional analysis showed that the value of the activation energy for the initiation reaction or C-8, C-12, and C-16 were $61.7{\sim}57.7kJ/mol$, $63.0{\sim}57.3 kJ/mol$, and $130.4{\sim}94.2 kJ/mol$, respectively, depending on the catalyst used. The values of activation energy for the initiation is different as reported value of 20 kJ/mol which indicating the difference in the effect of the pendant side chain length of ASA in the initial stage of the reaction.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.704-708
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• 2015

For the analysis of multiple-reaction intermediates for long-chain dicarboxylic acid biotransformation, simple and reproducible methods of extraction and derivatization were developed on the basis of gas chromatography with flame ionization detector (GC-FID) instead of mass spectrometry. In the derivatization step, change of the ratio of pyridine to MSTFA from 1:3 to 9:1 resulted in higher peak intensity (p = 0.021) and reproducibility (0.6%CV) when analyzing 32 g/l ricinoleic acid (RA). Extraction of RA and ω-hydroxyundec-9-enoic acid with water containing 100 mM Tween 80 showed 90.4-99.9% relative extraction efficiency and 2-7%CV compared with those with hydrophobic ethyl acetate. In conclusion, reduction of the pyridine content and change of the extraction solvent to water with Tween 80 provided compatible derivatization and extraction methods to GC-FID-based analysis of longchain carboxylic acids.

• Pediatric Infection and Vaccine
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• v.3 no.2
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• pp.207-213
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• 1996

Herpes simplex virus(HSV) infections of the CNS are associated with significant morbidity and mortality even when appropriate antiviral therapy is administered. HSV infections of the brain can be subdivided into two categories : neonatal HSV infections, which usually are caused by HSV type 2, and herpes simplex encephalitis(HSE), which occur in patients over 3 months old and is nearly uniformly caused by HSV type 1. The clinical presentation of HSE is one of the focal encephalopathic process associated with altered levels of consciousness, fever, focal seizures and hemiparesis. But because of the lack of pathognomic clinical presentation and diagnostic procedure, the efforts to develop alternative diagnostic procedure have led to the use of new diagnostic technique such as polymerase chain reaction(PCR). We report a case of HSV type 1 encephalitis in 13 month old male infant who presented with altered level of consciousness, fever and focal seizures. With the use of the PCR, HSV-1 DNA was detected in cerebrospinal fluid from the patient. The symptoms and signs of encephalitis subsided by treatment with acyclovir in 14 days.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.45-52
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• 2000

Nowadays, there are a lot of evidence that mutation of the p53 tumor suppressor gene is one of the most common genetic abnormalities in neoplastic progression. In this study, we analyzed 20 specimens of oral tumors(squamous cell carcinoma 14 cases, ameloblastoma 3 cases, adenoid cystic carcinoma 2 cases, malignant schwannoma 1 case)using polymerase chain reaction and direct sequencing which used an automated DNA sequencer and software for detection of mutations. Polymerase chain reactions were performed with 4 sets of primers encompassing exon 5, 6, 7, 8, and direct sequencing method was employed. The results were as followings. 1. We detected 10 point mutations out of 20 specimens (50%). 2. The genetic alterations included 7 mis-sense mutations resulting in single amino acid subtitutions, 2 silent mutations, 1 non-sense mutations encoding a stop codon. 3. Mutations were mostly in exon 7(7 out of 10 mutations, 70%) and involved codons 225, 234, 235, 236, 238, 247. 4. Therse were 4 cases of $T{\rightarrow}A$ transversion, 2 cases of $C{\rightarrow}A$ transversion, $A{\rightarrow}G$ transition, 1 case of $C{\rightarrow}G$, $T{\rightarrow}G$ transversion respectively. 5. We could find out point mutations more conveniently using PCR - Automated Direct Sequencing method.

• Macromolecular Research
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• v.17 no.8
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• pp.557-562
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• 2009

The free radical polymerization of styrene was initiated with azobis(isobutyronitrile) in the presence of benzene sulfonyl chloride. Analysis of the terminal structures of the obtained polystyrene with $^1H$ NMR spectroscopy revealed the presence of a phenyl sulfonyl group at the ${\alpha}$-end and a chlorine atom at the ${\omega}$-end of each polystyrene chain. The terminal chlorine atom in the polystyrene chains was further confirmed through atom transfer radical polymerization (ATRP) of styrene and methyl acrylate using the obtained polystyrenes as macroinitiators and CuCl/2,2'-bipyridine as the catalyst system. GPC traces of the products obtained in ATRP at different reaction times were clearly shifted to higher molecular weight direction, indicating that nearly all the macroinitiator chains initiated ATRP of the second monomers. In addition, the number-average molecular weights of the polystyrenes increased directly proportional to the monomer conversions, and agreed well with the theoretical ones.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.162-166
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• 1996

The protein coding sequence of the 4-aminobutyrate aminotransferase was amplified by polymerase chain reaction (PCR) from a previously cloned cDNA of pig brain using a pair of primers based on the published sequence. The amplified DNA was introduced into a T7 expression vector. Recombinant 4-aminobutyrate aminotransferases were overexpressed in Escherichia coli. The inclusion bodies were formed when enzyme was overexpressed. The unfolded, overproduced proteins were purified by chromatography with hydroxyapatite and refolded by a sequential dialysis method. The renatured 4-aminobutyrate aminotransferase regained the catalytic activity. However, the purified mutant protein did not show the catalytic function of 4-aminobutyrate aminotransferase.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.592-595
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• 2000

In human chromosome, a short sequence of DNA has been repeated a number of times. These repeats are called variable number of tandem repeat(VNTR) or short tandem repeat(STR) which has short repeat core. VNTR and STR are used in the field of forensic science, evolution, and anthropology. In this work, we examined allele frequencies of 3 VNTR(YNZ22, NeuR, D21S11) and one STR(Humth01) in a Korean population sample by polymerase chain reaction(PCR) followed by high-resolution polyacrylamide gelelectrophoresis(PAGE) with silver staining. Subsequently, the polymorphism information content(PIC) was calculated : the highest PIC was observed for the NeuR locus(0.95680) and lowest for the Humth01 locus(0.75809).