• Toxicological Research
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• v.17
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• pp.185-188
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• 2001

Genetically modified foods and food additives are derived from organisms that have been inserted foreign genetic materials by recombinant DNA techniques to improve the quality or any other pur-poses. The problems such as toxicity, allergenicity and antibiotics resistance in the safety of genetically modified foods are usually concerned. In Korea, the safety of foods is ensured by the Food Sanitation Act. Although there is no specific provision regarding the genetically modified foods in it, any foods that might cause negative effect(s) on public health or human life are prohibited to sell in the market. In order to systematically evaluate safety of genetically modified foods, the Korea Food and Drug Administration (KFDA) promulgated "Guidelines regarding review of safety assessment data for genetically modified foods and food additives (KFDA Notification 1999-46)". The objectives of these guidelines are to ensure safety of genetically modified foods and food additives. In order to evaluate the safety of genetically modified foods. KFDA operates a special expert committee composed by experts from government, universities, research institutes. and consumer's unions. Recently. manufacturers and consumers are interested in the issues on safety and labeling of genetically modified foods, because of increment of imported genetically modified crops and processed foods. Since government and consumers unions have different viewpoints, their positions regarding the issue are different each other. Therefore, the regulation of labeling on genetically modified foods is prepared and should be enforced at July 2000 in Korea. in Korea.

• Toxicological Research
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• v.25 no.2
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• pp.85-92
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• 2009

4,4'-Methylenedianiline (MDA) is an aromatic amine that is widely used in the industrial synthetic process. Genotoxic MDA forms DNA adducts in the liver and is known to induce liver damage in human and rats. To elucidate the molecular mechanisms associated with MDA-induced hepatotoxicity, we have identified genes differentially expressed by microarray approach. BALB/c male mice were treated once daily with MDA (20 mg/kg) up to 7 days via intraperitoneal injection (i.p.) and hepatic damages were revealed by histopathological observation and elevation of serum marker enzymes such as AST, ALT, ALP, cholesterol, DBIL, and TBIL. Microarray analysis showed that 952 genes were differentially expressed in the liver of MDA-treated mice and their biological functions and canonical pathways were further analyzed using Ingenuity Pathways Analysis (IPA). Toxicological functional analysis showed that genes related to hepatotoxicity such hyperplasia/hyperproliferation (Timp1), necrosis/cell death (Cd14, Mt1f, Timp1, and Pmaip1), hemorrhaging (Mt1f), cholestasis (Akr1c3, Hpx, and Slc10a2), and inflammation (Cd14 and Hpx) were differentially expressed in MDA-treated group. This gene expression profiling should be useful for elucidating the genetic events associated with aromatic amine-induced hepatotoxicity and for discovering the potential biomarkers for hepatotoxicity.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.153-157
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• 2006

A soil metagenomic library was constructed using an E. coli-fosmid cloning system with environmental DNAs extracted from Kwangreung forest topsoil. We targeted the genes involved in the biosynthesis of bacterial polyketides. Initially, a total of 36 clone pools (10,800 clones) were explored by the PCR-based method using the metagenomic DNAs from each pool and a degenerate primer set, which has been designed based on the highly conserved regions among ketoacyl synthase (KS) domains in actinomycete type I polyketide synthases (PKS Is). Six clone pools were tentatively selected as positive and further examined through a hybridization-based method for selecting a fosmid clone containing PKS I genes. Colony hybridization was performed against fosmid clones from the 6 positive pools, and finally 4 clones were picked out and confirmed to contain the conserved DNA fragment of KS domains. In this study, we present a simple and feasible sorting method for a desired clone from metagenomic libraries.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1230-1237
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• 2009

The selective plugging strategy of Microbial Enhanced Oil Recovery (MEOR) involves the use of microbes that grow and produce exopolymeric substances, which block the high permeability zones of an oil reservoir, thus allowing the water to flow through the low permeability zones leading to increase in oil recovery. Bacillus licheniformis TT33, a hot water spring isolate, is facultatively anaerobic, halotolerant, and thermotolerant. It produces EPS as well as biosurfactant and has a biofilm-forming ability. The viscosity of its cell-free supernatant is $120\;mPa{\cdot}s$ at $28^{\circ}C$. Its purified EPS contained 26% carbohydrate and 3% protein. Its biosurfactant reduced the surface tension of water from 72 to 34 mN/m. This strain gave $27.7{\pm}3.5%$ oil recovery in a sand pack column. Environmental scanning electron microscopy analysis showed bacterial growth and biofilm formation in the sand pack. Biochemical tests and Amplified Ribosomal DNA Restriction Analysis confirmed that the oil recovery obtained in the sand pack column was due to Bacillus licheniformis TT33.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1016-1023
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• 2008

Lichens are predominant and important components of flora in the terrestrial ecosystem of Antarctica. However, relatively few researches on the phylogenetic position of Antarctic lichen-forming fungi have been accomplished. In this study, partial sequences of nuclear large subunit rDNAs from 50 Antarctic specimens were obtained and the phylogeny was reconstructed. Antarctic lichen species were distributed in 4 orders, including the monophyletic order Agyrales, paraphyletic orders Pertusariales and Teloschistales, and polyphyletic order Lecanorales. Species diversity was highest in the order Lecanorales, followed by Teloschistales and Pertusariales. Based on the phylogeny and sequence similarity analyses, it is proposed that the taxonomy of Stereocaulon alpinum, Physcia caesia, Usnea aurantiacoatra, and Cladonia species should be revised by careful examination of their phenotypic and molecular characteristics. Six species known to be endemic to Antarctica, Catillaria corymbosa, Himantormia lugubris, Leptogium puberulum, Pertusaria pertusa, Rhizoplaca aspidophora, and Umbilicaria antarctica, formed unique lineages, implying independent origins in the Antarctic area.

• Journal of Applied Biological Chemistry
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• v.60 no.1
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• pp.41-47
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• 2017

Genetic differentiation and antioxidant activities in ethanolic extracts from leaves of Bouea macrophylla Griffith were determined. The result revealed genetic differentiation among sour ma-praang, ma-yong and sweet ma-praang of B. macrophylla Griffith (${\phi}_{PT}=0.772$, p-value=0.000). In addition, high genetic diversities were found in sour ma-praang and sweet ma-praang populations (P: 51.4 and 57.1 %; He: 0.1900.035 and 0.2240.036, respectively), but low genetic diversity was found in ma-yong population (P: 8.6 %; He: 0.0350.021). Total phenolic contents of sour ma-praang, ma-yong and sweet ma-praang were estimated as $680.51{\pm}89.81$, $701.03{\pm}59.89$ and $530.85{\pm}41.23mg$ gallic acid/g extract, respectively. Free radical scavenging activities of sour mapraang, ma-yong and sweet ma-praang were found (1/EC50=4.17, 1.43 and 1.37, respectively) corresponding with metalchelating activities (1/EC50=0.83, 0.65 and 0.17, respectively). Therefore, the obtained data may be applied to cultivation and utilization of their leaves as source of natural phenolics and antioxidants.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.183-189
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• 2007

Shigellosis is the most common bacterial gastroenteritis both in developing and developed countries, but bacteremia due to Shigella spp. is very rare. In developed countries recent shigellosis is mostly caused by S. sonnei, but S. flexeri infection is rare. We had rare cases of S. flexeri infections in a family in the Jeonbuk Province: an 8-year-old boy with bacteremic shigellosis and 10- and 12-year-old brothers with diarrhea. The isolates had identical biochemical characteristics, and were resistant to ampicillin, chloramphenicol, and co-trimoxazole. PFGE pattern of Not I-restricted genomic DNA suggested that the isolate from blood was closely related to the two strains isolated from stool which had an identical PFGE pattern.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1135-1139
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• 2005

Psychrotrophic phenanthrene-degrading bacteria were identified in the sediment samples collected from Lake Baikal, Russia. Among 70 phenanthrene-degrading isolates, the seven that had the highest phenanthrene-degradation rates were identified by 16S rDNA sequencing. Isolate P25, identified as the Gram-positive rod-shaped organism Rhodococcus erythropolis, had the highest growth and degradation rate at $15^{\circ}C$. It could remove $26.0\%$ of 100 mg $1^{-1}$ phenanthrene in 20 days at $15^{\circ}C$, and degradation was less at $5^{\circ}C\;and\;25^{\circ}C$. The addition of surfactants to enhance degradation was tested. Brij 30 and Triton X-100 inhibited degradation at all surfactant concentrations tested, but Tween 80 stimulated phenanthrene degradation, especially at low concentrations. When $20{\times}$ CMC (critical micelle concentration) of Tween 80 was added, $38.0\%$ of 100 mg $1^{-1}$ phenanthrene was degraded in 12 days at $15^{\circ}C$. This psychrotrophic phenanthrene-degrading bacterium is a candidate for use in bioremediation of polycyclic hydrocarbon contamination in low temperature environments.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.394-399
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• 2003

The in vitro cytotoxic effects of newly synthesized copper (II) glycinate complex were investigated in two gastric cancer cell lines of SNU484 and SNU638 cells. The complex inhibited the growth and decreased the viability of both gastric cancer cells in a dose-dependent manner. Gastric cancer tells treated with the complex exhibited the features of apoptosis, as demonstrated by fragmentation of chromosomal DNA, activation of caspase-3-like enzyme, and cleavage of poly［ADP-ribose］ polymerase (PARP). With the treatment of copper (II) glycinate complex, the active form of caspase-3 was observed in SNU484 cells, but not in SNU638 cells, indicating that an alternative pathway of apoptosis might have been triggered in SNU638 cells. In conclusion, copper (II) glycinate complex induces apoptosis of SNU484 and SNU638 gastric cancer cells, and it is suggested that novel copper (II) glycinate complex is highly active against human gastric cancer cells.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.913-918
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• 2007

A Gram-positive, aerobic, rod-shaped, nonmotile, endospore-forming bacterium, designated Gsoil $349^T$, was isolated from soil of a ginseng field and characterized using a polyphasic approach. Comparative analysis of 16S rRNA gene sequences revealed that the strain Gsoil $349^T$ belongs to the family Paenibacillaceae, and the sequence showed closest similarity with Cohnella thermotolerans DSM $17683^T$ (94.1%) and Cohnella hongkongensis DSM $17642^T$ (93.6%). The strain showed less than 91.3% 16S rRNA gene sequence similarity with Paenibacillus species. In addition, the presence of MK-7 as the major menaquinone and $anteiso-C_{15:0},\;iso-C_{16:0},\;and\;C_{16:0}$ as major fatty acids suggested its affiliation to the genus Cohnella. The G+C content of the genomic DNA was 53.4 mol%. On the basis of its phenotypic characteristics and phylogenetic distinctiveness, strain Gsoil $349^T$ should be treated as a novel species within the genus Cohnella for which the name Cohnella panacarvi sp. nov. is proposed. The type strain is Gsoil $349^T\;(=KCTC\;13060^T=\;DSM\;18696^T)$.