• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1460-1468
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• 2007

In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.1-8
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• 2015

In this study, a DNA-launched reverse genetics system was developed from a type 2 porcine reproductive and respiratory syndrome virus (PRRSV) strain, KNU-12. The complete genome of 15,412 nucleotides was assembled as a single cDNA clone and placed under the eukaryotic CMV promoter. Upon transfection of BHK-tailless pCD163 cells with a full-length cDNA clone, viable and infectious type 2 progeny PRRSV were rescued. The reconstituted virus was found to maintain growth properties similar to those of the parental virus in porcine alveolar macrophage (PAM) cells. With the availability of this type 2 PRRSV infectious clone, we first explored the biological relevance of ORF5a in the PRRSV replication cycle. Therefore, we used a PRRSV reverse genetics system to generate an ORF5a knockout mutant clone by changing the ORF5a translation start codon and introducing a stop codon at the 7^th codon of ORF5a. The ORF5a knockout mutant was found to exhibit a lack of infectivity in both BHK-tailless pCD163 and PAM-pCD163 cells, suggesting that inactivation of ORF5a expression is lethal for infectious virus production. In order to restore the ORF5a gene-deleted PRRSV, complementing cell lines were established to stably express the ORF5a protein of PRRSV. ORF5a-expressing cells were capable of supporting the production of the replicationdefective virus, indicating complementation of the impaired ORF5a gene function of PRRSV in trans.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.83-89
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• 2001

Recent advances in the structural and molecular biology uncovered that a set of translation factors resembles a tRNA shape and, in one case, even mimics a tRNA function for deciphering the genetic ：ode. Nature must have evolved this 'art' of molecular mimicry between protein and ribonucleic acid using different protein architectures to fulfill the requirement of a ribosome 'machine'. Termination of protein synthesis takes place on the ribosomes as a response to a stop, rather than a sense, codon in the 'decoding' site (A site). Translation termination requires two classes of polypeptide release factors (RFs)： a class-I factor, codon-specific RFs (RFI and RF2 in prokaryotes; eRFI in eukaryotes), and a class-IT factor, non-specific RFs (RF3 in prokaryotes; eRF3 in eukaryotes) that bind guanine nucleotides and stimulate class-I RF activity. The underlying mechanism for translation termination represents a long-standing coding problem of considerable interest since it entails protein-RNA recognition instead of the well-understood codon-anticodon pairing during the mRNA-tRNA interaction. Molecular mimicry between protein and nucleic acid is a novel concept in biology, proposed in 1995 from three crystallographic discoveries, one, on protein-RNA mimicry, and the other two, on protein-DNA mimicry. Nyborg, Clark and colleagues have first described this concept when they solved the crystal structure of elongation factor EF- Tu：GTP：aminoacyl-tRNA ternary complex and found its overall structural similarity with another elongation factor EF-G including the resemblance of part of EF-G to the anticodon stem of tRNA (Nissen et al. 1995). Protein mimicry of DNA has been shown in the crystal structure of the uracil-DNA glycosylase-uracil glycosylase inhibitor protein complex (Mol et al. 1995; Savva and Pear 1995) as well as in the NMR structure of transcription factor TBP-TA $F_{II}$ 230 complex (Liu et al. 1998). Consistent with this discovery, functional mimicry of a major autoantigenic epitope of the human insulin receptor by RNA has been suggested (Doudna et al. 1995) but its nature of mimic is. still largely unknown. The milestone of functional mimicry between protein and nucleic acid has been achieved by the discovery of 'peptide anticodon' that deciphers stop codons in mRNA (Ito et al. 2000). It is surprising that it took 4 decades since the discovery of the genetic code to figure out the basic mechanisms behind the deciphering of its 64 codons.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.82-90
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• 2016

Most Araliaceae plant species distributed in Korea are economically important because of their high medicinal values. This study was conducted to develop barcode markers from sequence analysis of chloroplast DNA in 14 taxa of Araliaceae species grown in South Korea. Sequencing of seven chloroplast DNA regions was performed to establish the DNA barcode markers, as suggested by the Consortium for the Barcode of Life (CBOL). From the sequence analysis of chloroplast DNA, we identified specific sequences and nucleotides that allowed us to discriminate among each other 14 Korean Araliaceae species. The sequence in the region of psbA-trnH revealed the most frequent DNA indels and substitutions of all 7 regions studied. This psbA-trnH marker alone can discriminate among all 14 species. There are no differences between Korean and Chinese Panax ginseng in all seven sequenced chloroplast DNA regions. A phylogenetic tree constructed using the seven chloroplast DNA regions revealed that Tetrapanax papyriferus should be classified as an independent clade. The Aralia and Panax genera showed a close phylogenetic relationship. Five species in the Eleutherococcus genus were more closely related to Kalopanax septemlobus than to any Panax species.

• The Plant Pathology Journal
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• v.18 no.5
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• pp.251-258
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• 2002

A potyvirus was isolated from cultivated Iris plants showing leaf streak mosaic symptom. Reverse transcription and polymerase chain reaction (RT-PCR) product of 1 kb long which encoded partial nuclear inclusion B and N-terminal region of viral coat protein (CP) genes for potyviruses was successfully amplified with a set of potyvirus-specific degenerate primers with viral RNA samples from the infected leaves: The RT-PCR product was cloned into the plasmid vector and its nucleotide sequences were determined. The nucleotide sequence of a CDNA clone revealed that the virus was an isolate of Ornithogalum moseic virus (OrMV) based on BLAST search analysis and was denoted as OrMV Korean isolate (OrMV-Ky). To further characterize the CP gene of the virus, a pair of OrMV-specific primers was designed and used for amplification of the entire CP gene of OrMV-Kr, The virus was easily and reliably detected from virus-infected Iris leaves by using the RT-PCR with the set of virus-specific primers. The RT-PCR product of the CP gene of the virus was cloned and its sequences were determined from selected recombinant CDNA clones. Sequence analysis revealed that the CP of OrMV-Kr consisted of 762 nucleotides, which encoded 253 amino acid residues. The CP of OrMV-Ky has 94.1-98.0% amino acid sequence identities (20 amino acid alterations) with that of other three isolates of OrMV, Two NT rich potential N-glycosylation motif sequences, NCTS and NWTM, and a DAC triple box responsible for aphid transmission were conserved in CPs of all the strains of OrMV. The virus has 58.5-86.2% amino acid sequence identities with that of other 16 potyviruses, indicating OrMV to be a distinct species of the genus. OrMV-Ky was the most related with Pterostylia virus Yin the phylogenetic tree analysis of CP at the amino acid level. This is the first report on the occurrence of OrMV in Iris plants in Korea. Data in this study indicate that OrMV is found in cultivated Iris plants, and may have mixed infection of OrMV and Iris severe mosaic virus in Korea.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.241-245
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• 1995

Focusing on quality problems of delayed chilling porcine muscle, the effects of delayed chilling and aging on the contents of ATP-related compounds and taste of pork were investigated. Twelve Landrace pigs were employed and bisected: left sides were delay-chilled(DC) at room temperature($20^{\circ}C$) for 3 hrs, whereas right sides were conventionally chilled(CC). ATP-related compounds tested were adenosine triphosphate(ATP) and its derivatives in pork muscle, inosine monophosphate(IMP), guanosine monophosphate(GMP) and L-glutamate in cooked broth. DC sides showed more rapid pH decline and degradation of nucleotides than did CC sides. The levels of ATP and adenosine monophosphate(AMP) were not changed significantly. However, adenosine diphosphate(ADP) and IMP showed the highest levels at the 1st and 5th day, respectively. Hypoxanthine(Hx) was gradually increased(p<0.05) during aging. During aging, the IMP contents cooked broth tended to decrease, while the GMP and L-glutamate contents increase. As a result of these, the taste score got better and finally the results of sensory evaluation became increased(p<0.05). However, compared to CC sides, DC sides did not seem to lower taste of pork.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.293-302
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• 1988

This study was performed to identify detailed informations on the nonvolatile flavor of Chinese quince fruits, Chaenomeles sinensis koehne. About 72% of the free amino acids were shown to be valine, asparagine, ${\gamma}-aminobutyric\;acid$, aspartic acid and serine. Arginine, tyrosine, methionine and tryptophan were not present. Glutamic acid and glutamine as a amino acid for peptides were the major components, whereas cysteic acid, methionine sulfone and tryptophan were not detected. The nucleotides attained were composed of cytosine, uridine-5'-monophosphate and cytidine-5'-monophosphate, and these were proved to be a very small quantity. Guanosine-5'-monophosphate, inosine-5'-monophosphate and adenosine-5'-monophosphate were not present. The major sugars were shown to be glucose, sorbose, sucrose and fructose. Fructose was the most abundant one among them. A total of 11 organic acids were identified by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The major components identified were tartaric acid and α-ketoglutaric acid. The total content of vitamin C determined was 386.6mg%, and those of ascorbic, dehydroascorbic, and 2, 3-diketo-L-gulonic acid were 28.8mg%, 154.5mg% and 197.3mg%, respectively. Calcium and phosphorus were the major components, while heavy metals such as cadmium, copper and lead were determined to be a small amount. In the result of organoleptic test on the natural and synthetic extract of Chinese quince fruits, the principal taste components consisted of free amino acids, sugars, organic acids, vitamin C and minerals. Five groups mentioned would have a favorable influence upon the taste of fresh Chinese quince fruits.

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.37-46
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• 1987

SULNONGTANG is a kind of “goomkok”-korean typical soup made with beef, tone and organs, and is belived to be as a good source of portein and calcium, but there is no standard formulation for that. In order to set up the standard formulation of SULNONGTANG cooking method, I have performed a nutritional analysis of change in the components of SULNONGTANG, which contained the proximate composition, free amino acids, nucleotides, cholesterol, calium, phosphorus and iron. The conventional SULNONGTANG were cooked by conventional methods varing cooking time and ingredient. And also the current Market SULNONGTANG were cooked by the same methods for conventional SULNONGTANG and adding beef's head, hooves or knee tones. The result obtained in this study were as fallows: 1. In case of conventional SULNONGTANG, the most desirable cooking time was from 12 to 18 hours, the preparation method for group A was the best to maintain the optimal amount of nutrients and 5'-IMP. 2. In Market SULNONGTANG, nutritional contents were poorer than that of conventional SULNONGTANG. When the beef's head was added to the Market SULNONGTANG, nutritional status were more desirable than those added hooves or knee bones.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.254-259
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• 1992

The processing conditions and food components of meaty textured sardine burgers were studied to develope a new form of burger, The separated sardine meat was chopped, mixed with 14.1% emulsion curd, 1.5% table salt, 2.0% sugar, 0.4% sodium bicarbonate, 0.2% polyphosphate, 0.1% monosodium glutamate, 8.0% bread powder, 0.4% onion powder, 0.1% garlic powder, 0.1% ginger powder and 3.0% soybean protein by remodeled stone mortar. This seasoned sardine meat was fried in soybean oil $(165{\pm}2^{\circ}C,\;3min)$. The main fatty acids of sardine burger were palmitic acid, oletic, acid, linoleic acid, eicosapentaenoic acid and docosahexaenoic acid. Amino acid composition of sardine burger were mainly consisted of histidine, glutamic acid, leucine and lysine. The major taste compounds in the product were revealed nucleotides and their related compounds $(11.19{\sim}11.96\;{\mu}mole/g)$ such as IMP and free amino acids (1824.8 mg/100g) such as histidine, glutamic acid, leucine and lysine. Total creatinine, betaine and trimethylamine oxide were seemed to act an auxiliary role in taste of product.

• Korean Journal of Human Ecology
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• v.3 no.2
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• pp.77-89
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• 2000

In this study, to activate the industrialization and to improve the quality of Toha-jeot by shortening the fermentation period, we investigated the changes in the nutritional components of Toha-jeot. salt-fermented Toha shrimp( Caridina denticulata denticulata $D_{E}$ $H_{AAN}$) which was salted with a low-salt group and high-salt group during fermentation. In this experiment. there are four groups of Toha-jeot which were manufactured with 15% ratio of common salt: the first group containing 2% wheat bran (w2%-L). the second high-salt group containing 2% wheat bran( w2%-H) , the third low-salt group containing 4% wheat bran (w4%-L) and the last high-salt group containing 4% wheat bran(w4%-H). These four groups were refrigerated at 4${\pm}$1$^{\circ}C$ and then taken out for analysis at three month intervals during 9 month. Among the free amino acid contents in Toha-jeot, 22 kinds were detected. 6 month after the fermentation when the quantity of the amino acid contents in Toha-jeot is highest, ornitine, glutamic acid, leucine. alanine. lysine and valine occupy the majority, in the order of abundance. In cases of nucleotides. 6 month after the fermentation. from the groups w2%-L, w2%-H and w4%-L, inosine and IMP were not detected. and hypoxanthine, AMP, ADP were detected but 9 month after the fermentation ADP was not detected. The main constituents of fatty acid were as follows : (a) from w2%-L, w2%-H, 6 month after the fermentation. $C16:0$, $C12:0$, $C18:1$, $C18:3$, and $C16:1$. (b) from w4%-L. 6 month after the fermentation, $C18:3$, $C16:0$, $C12:0$ and $C18:1$. (c) from W4%-H, $C16:0$, $C12:0$, $C18:3$ and $C18:1$. In case of mineral contents. Na, Ca. K. Mg, Fe. Zn, Mn and Cu were detected according to the magnitude of the quantity. From the group w4%-H, high quantity of Na was detected during the total fermentation period. In case of color value, from the groups w2%. the values of L. a. b were highest after 6 month fermentation and were decreased after 9 month fermentation, while from groups w4%, the values of L, a, b were gradually decreased after 3 month fermentation.ion.