• 생명과학회지
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• 제23권4호
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• pp.487-494
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• 2013

T-DNA가 표지된 집단에서 AlaAT 유전자가 깨어진 돌연변이체(alaat)를 분리하고, AlaAt1 특이 프라이머를 이용하여 유전자형을 결정하였다. Alaat의 표현형은 대조구와 비교해서 생장의 감소를 보였고, 종자 역시 작고 생산성의 감소를 보였다. 돌연변이체의 AlaAT 활성은 거의 검출되지 않았다. 고염 스트레스 하에서 alaat의 반응을 엽록소 형광과 항산화 효소들의 활성 및 RT-PCR을 이용하여 대조구와 비교하였다. 고염, 건조 및 저온과 같은 모든 비생물적 스트레스에 대한 Fv/Fm은 대조구와 alaat 둘 다 감소를 보였으며, 비생물적 스트레스에 대한 엽록소 형광은 거의 유사하였다. 항산화 효소인 peroxidase (POX)의 활성은 고염 스트레스에 의해 대조구는 증가하나 alaat에서는 오히려 감소하였다. RT-PCR에 의한 cAPX, POX 및 AlaAT mRNA의 수준을 분석한 결과, 효소 활성과 마찬가지로 AlaAt mRNA는 alaat에서 나타나지 않았고, POX2 mRNA는 대조구는 약간의 증가를 보이나 alaat는 거의 검출할 수 없었다. cAPX mRNA는 대조구와 alaat 모두 고염 스트레스에 의해 크게 증가하였다. 이 같은 결과는 AlaAT 유전자 기능의 상실은 염 스트레스 하에서 벼 식물의 생장에 대해 광합성능 보다는 항산화 효소, 특히 POX 활성 및 합성을 변화시킬 수 있음을 제안한다.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1377-1383
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• 2006

Among 46 Acinetobacter baumannii isolates collected in 2004, two imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Republic of Korea. Two carbapenemase-producing isolates were further investigated to determine the mechanism of resistance. These isolates were analyzed by antibiotic susceptibility testing, microbiological tests of carbapenemase activity, determination of pI, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. Two cases of infection by A. baumannii producing the IMP-1 ${\beta}$-lactamase were detected. The isolates were characterized by a modified cloverleaf synergy test and EDTA-disk synergy test. Isoelectric focusing of crude bacterial extracts revealed nitrocefin-positive bands with a pI value of 9.0. PCR amplification and characterization of the amplicons by direct sequencing indicated that the isolates carried a $bla_{IMP-l}$ determinant. The isolates were characterized by a multidrug resistance phenotype, including penicillins, extended-spectrum cephalosporins, carbapenems, and aminoglycosides. These results indicate that the observed imipenem resistance of two Korean A. baumannii isolates was due to the spread of an IMP-1-producing clone. Our microbiological test of carbapenemase activity is simple to screen class B metallo-${\beta}$-lactamase-producing clinical isolates to determine their clinical impact and to prevent further spread. This study shows that the $bla_{IMP-l}$ resistance determinant, which is emerging in Korea, may become an emerging therapeutic problem, since clinicians are advised not to use extended-spectrum cephalosporins, imipenem, and aminoglycosides. This observation emphasizes the importance of having effective control measures in Asian hospitals, such as early detection of colonized patients, isolation procedures, and a judicious use of antibiotics.

• 미생물학회지
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• 제44권4호
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• pp.293-298
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• 2008

HCV는 HIV등과 함께 수혈이나 혈장된 획물질을 통하여 감염되는 주요 바이러스이다. 주로 혈액이나 혈장에서 HCV에 대한 항체를 검출함으로서 HCV의 감염을 방지하고 있다. 그러나 바이러스에 감염되었으나 항체가 생성되기 이전이나 항체의 양이 적은 경우에는 HCV의 검출이 어렵다. 따라서 핵산중폭시험(nucleic acid amplification tests, NAT)을 이용한 HCV 유전자를 검출하려는 시도들이 진행되고 있다. 이 연구의 목적은 혈장분획물질에서 HCV RNA를 검출할 수 있는 핵산증폭시험 방법을 개발하는 것이다. 5종류의 PCR primer를선별하여 실험에 이용하였다. 혈장분획물질의 HCV RNA 추출에는 컬럼 방법을 이용하는 것이 유용한 것으로나타났다. 핵산중폭시험의 결합 온도는 $48^{\circ}C$가 가장 적절한 것으로 나타났다. 또한 2차 PCR의 경우, 1차 PCR 산물 $1{\mu}l$와 30 pmol의 primer즐 사용하였을 때 높은 민감도와 특이성을 보이는 것을 알 수 있었다. 혈장 분획물질에 HCV를 주입하여 혈장중폭시험을 수행한 결과, 100 IU/ml까지 검출 할 수 있었다. 한편 근육주사용항체(IMIG)의 경우 핵산중폭시험을 통한 검출한계는 100IU/ml로 COBAS amplicor HCV2.0의 500 IU/ml 이상의 검출한계보다 민감도가 더 높은 것으로 나타났다. 이러한 결과들로 보아 본 실험에 이용된 핵산증폭시험이 혈장분획물질에서 HCV RNA를 검출하는데 유용한 방법으로 사용될 수 있을 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1344-1352
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• 2007

An opportunistic human pathogen, Pseudomonas aeruginosa, contains the major catalase KatA, which is required to cope with oxidative and osmotic stresses. As an attempt to uncover the $H_2O_2$-dependent regulatory mechanism delineating katA gene expression, four prototrophic $H_2O_2$-sensitive mutants were isolated from about 1,500 TnphoA mutant clones of P. aeruginosa strain PA14. Arbitrary PCR and direct cloning of the transposon insertion sites revealed that one insertion is located within the katA coding region and two are within the coding region of oxyR, which is responsible for transcriptional activation of several antioxidant enzyme genes in response to oxidative challenges. The fourth insertion was within PA3815 (IscR), which encodes a homolog of the Escherichia coli iron-sulfur assembly regulator, IscR. The levels of catalase and SOD activities were significantly reduced in the iscR mutant, but not in the oxyR mutant, during the normal planktonic culture conditions. These results suggest that both IscR and OxyR are required for the optimal resistance to $H_2O_2$, which involves the expression of multiple antioxidant enzymes including KatA.

• The Plant Pathology Journal
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• 제20권3호
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• pp.229-233
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• 2004

The bacterial leaf blight, which is caused by Xantho-monas oryzae pv. oryzae, is the most damaging and intractable disease of rice. To identify the genes involved in the virulence mechanism of transposon TnS complex, which possesses a linearized transposon and transposase, was successfully introduced into X. oryzae pv. oryzae by electroporation. The transposon mutants were selected and confirm the presence of transposition in X. oryzae pv. oryzae by the PCR amplification of transposon fragments and the Southern hybridization using these mutants. Furthermore, transposon insertion sites in the mutant bacterial chromosome were deter-mined by direct genomic DNA sequencing using transposon-specific primers with ABI 3100 Genetic Analyzer. Efficiency of transposition was influenced mostly by the competence status of X. oryzae pv. oryzae cells and the conditions of electroporation. These results indicated that the insertion mutagenesis strategy could be applied to define function of uncharacterized genes in X. oryzae pv. oryzae.

• Asian-Australasian Journal of Animal Sciences
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• 제23권3호
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• pp.326-332
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• 2010

Daidzein, a natural isoflavonoid phytoestrogen, structurally resembles estradiol (E2) and possesses estrogenic activity. This study was designed to test the hypothesis that daidzein may mimic the effects of E2 on ovine follicle development by regulation of the mRNA expression of bone morphogenetic protein receptor genes and thereby influence the reproductive system. Granulosa cells were cultured in serum-free McCoy's 5A medium with and without supplementation of daidzein. Results showed that daidzein (10-100 ng/ml) significantly increased the proliferation of ovine granulosa cells (p<0.05), but inhibited the growth of granulosa cells at a dose of 1,000 ng/ml (p<0.01). Daidzein inhibited progesterone production in a dose dependent manner; however, it did not affect estradiol production by granulosa cells. We also investigated the effects of daidzein on BMPRII, BMPRIB and ALK-5 mRNA expression in ovine granulosa cells by quantitative real-time PCR. Treatment of granulosa cells with daidzein increased significantly expression of these genes at 10-100 ng/ml. Thus, these data suggested that a low concentration of daidzein (10-100 ng/ml) had a direct stimulatory effect on ovine granulosa cells while a high concentration was toxic.

• 대한치과교정학회지
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• 제25권6호
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• pp.723-731
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• 1995

Type I and type II collagens are considered the major collagens of bone and cartilage respectively. Monitoring the patterns of those gene and protein expressions during development will provide a basis for the understanding of the normal and abnormal growths. This study was undertaken to investigate the expression of collagen genes and proteins involved in the developing human mandible. Fifty embryos and fetuses were studied with Alcian blue-PAS, Masson's Trichrome, reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and Southern blot analysis. Our results showed that $pro-{\alpha}1(II)$ collagen gene expression begins in the 5th week. Type II collagen is synthesized in mesenchymal cells in advance: of overt chondrogenesis. The gene expression for type II collagen was highest during the appearance of Meckel's cartilage. There was a switch in collagen protein expression from type I to type II during the appearance stage of Meckel's cartilage. The distribution of the mRNA for type II collagen corresponded well with the pattern of type II collagen protein. The endochondral ossification was observed where there was direct replacement of cartilage by bone.

• International Journal of Industrial Entomology and Biomaterials
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• 제2권1호
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• pp.87-89
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• 2001

The nucleotide sequence of the domestic silkworm (Bombyx mori) mitochondrial (mt) control region and its flanking genes was determined from PCR clones. The control region of the silkworm mt genome was located between the small ribosomal RNA gene and transfer RN $A^{Met}$. This 499 bp control region hale 95.4% A+T content. Extensive comparative analysis studies performed with similar control region of other insect genomes could not reveal a highly conserved region containing conserved motifs of animal mito-chondrial genome. The remarkable feature that found in this control region was the presence of tandem motifs containing nine repetitive sequences. The potential usefulness of this motif sequences for Bombyx species or their taxonomically related species is enhanced by its unique localization in the maternally inheritance mitochondrial molecule.e.

• Molecular & Cellular Toxicology
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• 제1권1호
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• pp.40-45
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• 2005

Ursodeoxycholic acid (UDCA) has long been used as an adjuvant or first choice of therapy for liver disease. Commonly, UDCA has been reported to play a role in improving hyperbilirubinemia and disorder of bromsulphalein. More commonly, UDCA has been used in reducing the rate of cholesterol level in bile juice that can cause cholesterol stone. The effects on the promotion of bile acid release that leads an excretion of toxic materials and wastes produced in liver cells as well as various arrays of liver disease such as hepatitis. Other than already reported in clinical use, immunosuppressive effect has been studied, especially in transplantation. In the study, we hypothesized that UDCA might have a certain role in anti-inflammation through a preventive effect of pro-inflammatory potentials in the brain macrophages, microglia. We found that the treatment of $200\;{\mu}g/ml$ UDCA effectively suppressed the pro-inflammatory mediators (i.e. nitric oxide and interleukin-$1{\beta}$) in rat microglia compared to comparators. Interestingly, RT-PCR analysis suggested that UDCA strongly attenuated the expression of $IL-1{\beta}$ that was comparable with cyclosporine A at 48 h incubation. Conclusively, we found that UDCA may playa cytoprotective role in microglial cells through direct or indirect pathways by scavenging a toxic compound or an anti-inflammatory effect, which are known as major causes of neurodegenerative diseases.

• Asian Journal of Atmospheric Environment
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• 제5권3호
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• pp.172-180
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• 2011

The transfer of microorganisms is important process for ecosystems. Microorganisms in dryland can transport itself to wetland through atmospheric diffusion, but only few papers reported about the atmospheric bioaerosol present over dryland. We carried out the direct sampling using a tethered balloon over Dunhuang City, China's northwestern dryland. Bioaerosols were collected using a tethered balloon with a bioaerosol collector at 820 m above the ground (1,960 m above the sea level) around noon on August 17, 2007. The bioaerosols were cultured after the collection at Dunhuang Meteorological observatory. Two strains of molds were isolated using the Nutrient agar medium. About 400-bp 18S rRNA partial sequences were amplified by PCR and determined afterwards. The results of a homology search by 18S rRNA sequences of isolates in DNA databases (GenBank, DDBJ, and EMBL) and an observation of the form revealed that two bioaerosols in the convective mixed layer over Dunhuang City were Cladosporium sp. and Aspergillus sp.