• Bulletin of the Korean Chemical Society
• /
• 제35권4호
• /
• pp.1105-1109
• /
• 2014

While single strand DNAs have been widely used for the scaffold of brightly fluorescent silver nanoclusters (Ag NCs), double strand DNAs have not been as successful. Herein, we report a novel synthetic approach for bright Ag NCs using branched double strand DNAs as the scaffolds for synthesis. X-shaped DNA (X-DNA) and Y-shaped DNA (Y-DNA) effectively stabilized Ag NCs, and both X-DNA and Y-DNA resulted in brightly fluorescent Ag NCs. The concentration and molar ratio of silver and DNA were found important for the fluorescence efficiency. The brightest Ag NC with the photoluminescence quantum efficiency of 19.8% was obtained for the reaction condition of 10 ${\mu}M$ X-DNA, 70 ${\mu}M$ silver, and the reaction time of 48 h. The fluorescence lifetime was about 2 ns for the Ag NCs and was also slightly dependent on the synthetic condition. Addition of Cu ions at the Ag NC preparations resulted in the quenching of Ag NC fluorescence, which was different to the brightening cases of single strand DNA stabilized Ag NCs.

• 한국식품영양학회지
• /
• 제5권2호
• /
• pp.77-83
• /
• 1992

The optimum conditions and mechanisms for the plasmid-mediated genetic transformation of intact cells of Bacillus brevis Pl76-2, an extracellular protein producing bacterium by electroporation were investigated. It was found that pUB110 Plasmid DNA can be introduced into intact bacterial cells by electroporation. The frequency of transformation by this electroporation system depended upon the initial electric field strength, the capacity of the electric discharge capacitor, growth stage, number of successive pulses and composition of electroporation buffer. It was effective for transformation that cells were harvested, washed and resuspended with HSM [7M HEPES(PH 7.4), 272mM sucrose, 1 mM MgCl2] electroporation buffer when cell growth was attained to 1.2 at OD660. A maximum frequency of transformation of 2.40$\times$104 transformants per$\mu$g plasmid DNA was obtained by two succesive Pulses with an initial electric field strength of 12.5kV/cm and with a capacitance of 7.3uF.

• Journal of Microbiology and Biotechnology
• /
• 제34권9호
• /
• pp.1826-1835
• /
• 2024

Paracoccus denitrificans has been identified as a representative strain with heterotrophic nitrificationaerobic denitrification capabilities (HN-AD), and demonstrates strong denitrification proficiency. Previously, we isolated the DYTN-1 strain from activated sludge, and it has showcased remarkable nitrogen removal abilities and genetic editability, which positions P. denitrificans DYTN-1 as a promising chassis cell for synthetic biology engineering, with versatile pollutant degradation capabilities. However, the strain's low stability in plasmid conjugation transfer efficiency (PCTE) hampers gene editing efficacy, and is attributed to its restriction modification system (R-M system). To overcome this limitation, we characterized the R-M system in P. denitrificans DYTN-1 and identified a DNA endonuclease and 13 DNA methylases, with the DNA endonuclease identified as HNH endonuclease. Subsequently, we developed a plasmid artificial modification approach to enhance conjugation transfer efficiency, which resulted in a remarkable 44-fold improvement in single colony production. This was accompanied by an increase in the frequency of positive colonies from 33.3% to 100%. Simultaneously, we cloned, expressed, and characterized the speculative HNH endonuclease capable of degrading unmethylated DNA at 30℃ without specific cutting site preference. Notably, the impact of DNA methylase M9 modification on the plasmid was discovered, significantly impeding the cutting efficiency of the HNH endonuclease. This revelation unveils a novel R-M system in P. denitrificans and sheds light on protective mechanisms employed against exogenous DNA invasion. These findings pave the way for future engineering endeavors aimed at enhancing the DNA editability of P. denitrificans.

• 한국환경보건학회지
• /
• 제27권1호
• /
• pp.124-130
• /
• 2001

Ginkgo biliba has been used for bronchitis and asthma in oriental countries and its leaf extract(GBE) contains 24% ginkgoflavone glycoside and 6% terpenoid. Flavonoids and terpenoids are known to have various antioxidant effects such as scavenging of free radicals and chelation of transtional metals. Antioxidant effect of GBE against 1,2,4-benzenetriol(BT), one of toxic metabolites of benzene, was demonstrated throughbsister chromatid exchange(SCE) analysis, single cell gel electrophoresis(SCGE) analysis, DNA cleavage assay and lipid peroxidation production analysis. The means of SCE frequencies at 10, 25 and 50$\mu$M concentration of BT were 7.72, 8.02, 9.22 respectively. In addition of GBE with concentration of 50, 200 and 500$\mu\textrm{g}$/$m\ell$, SCE frequencies were decreased significantly.(p<0.05) According to SCGE analysis, BT induced DNA damage in a dose-dependent manner at concentration of 10 and 50 $\mu$m and the DNA damage induced by BT was significantly protected by GBE(p<0.001). No genotoxicity was observed by GBE treatment alone on DNA cleavage. The effect of BT on lipid peroxidation product, Malondiadehyde(MDA), was increased with concentration of BT(10 and 50 $\mu$M) and reduction in MDA was noted when GBE was added. From above results it is suggested that GBE could protect the cell and DNA from pro-oxidant effect by reactive oxigen species induced by BT.

• 대한의생명과학회지
• /
• 제12권4호
• /
• pp.349-354
• /
• 2006

Induction of apoptosis allows the organism to get rid of abnormal cells and also of tumor cells. Understanding the mechanism involved in Ultraviolet radiation (UV) induced apoptosis may improve its therapeutic efficacy. In this study, we present expression of poly (ADP-ribose) polymerase (PARP) during apoptosis induced by UV in HeLa $S_3$ cells. Four different assays were performed in this study: morphological assessment of apoptotic cells and cell viability, DNA fragmentation analysis by agarose gel electrophoresis, quantitative assay of fragmented DNA, and expression of PARP by the western blot analysis. The percentages of apoptotic HeLa $S_3$ cells irradiated with $75J/m^2$ UV was increased continuously from 3 hrs incubation. DNA ladder pattern was appeared at 6 hrs. The amount of nucleosomal DNA fragments in cells treated UV increased from 3 to 12 hrs incubation and gradually decreased. The cleavage of PARP in HeLa $S_3$ cells irradiated with UV was induced, and the cleavage of PARP was more delayed in the cells pretreated with $5J/m^2$ UV and subsequently irradiated with $75J/m^2$ UV. than that in the cells only irradiated with $75J/m^2$ UV. Thus these data suggest that the cleavage of PARP relates with DNA fragmentation associated with apoptosis.

• 대한수의학회지
• /
• 제39권4호
• /
• pp.797-805
• /
• 1999

T sergenti cDNA library were constructed to get a more broad information about the structural, functional or antigenic properties of the proteins, and analyzes for their partial cDNA sequences and expression sequences tags(ESTg). The mRNA were purified from T sergenti isolates to identify the information of antigen gene, then first and second strand cDNA was synthesized. EcoR I adaptor ligation and Xho I enzyme restriction were used to the synthesized cDNA, and ligated into a Uni-ZAP XR vector. T sergenti cDNA library was constructed with packaging and amplification in vitro. Antibody screening was performed with constructed T sergenti cDNA library using antisera against T sergenti. Among those clones, eight phagemids were rescued from the recombinant in vivo excision with f1 helper phage. Using the analysis of endonuclease restriction and PCR, the recombinant cDNA were proved having a 0.5-3.0kb of inserts. The eight of partial cDNA clones' sequences were obtained and examined for their homology using BLASTN and BLASTX. The eight of sequenced clones were classified into three groups according to the basis of database searches. A total 3,045bp of partial cDNA sequence were determined from six clones. The putatively identified clones contain a cytochrome c gene, a heat shock protein gene, a cyclophilin gene, and a ribosomal protein gene. The unidentified clones have a homology to ATP-binding protein(mtrA) gene of S argillaceus, DNA-binding protein(DBP) gene of Pseudorabies virus 85kDa merozoite protein gene of B bovis, mRNA spm1 protein of T annulata and glycine-rich RNA-binding protein mRNA of O sativa etc.

• Asian-Australasian Journal of Animal Sciences
• /
• 제27권10호
• /
• pp.1493-1498
• /
• 2014

Epigenetic factors, such as DNA methylation status, may regulate adipogenesis and lipogenesis, thus affecting intramuscular fat (IMF) deposition in longissimus dorsi muscle (LM) of beef cattle. In Korean cattle steers, the LM consists mainly of muscle tissue. However, the LM tissue also contains IMF. We compared the gene expression levels between the IMF and muscle portions of the LM after tissue separation. Real-time polymerase chain reaction analysis showed that the mRNA levels of both adipogenic peroxisome proliferator-activated receptor gamma isoform 1 (PPARG1) and lipogenic fatty acid binding protein 4 (FABP4) were higher (p<0.01) in the IMF than in the muscle portion of the LM. We determined DNA methylation levels of regulatory regions of the PPARG1 and FABP4 genes by pyrosequencing of genomic DNA. DNA methylation levels of two of three CpG sites in the PPARG1 gene promoter region were lower (p<0.05) in the IMF than in the muscle portion of the LM. DNA methylation levels of all five CpG sites from the FABP4 gene promoter region were also lower (p<0.001) in the IMF than in the muscle portion. Thus, mRNA levels of both PPARG1 and FABP4 genes were inversely correlated with DNA methylation levels in regulatory regions of CpG sites of the corresponding gene. Our findings suggest that DNA methylation status regulates tissue-specific expression of adipogenic and lipogenic genes in the IMF and muscle portions of LM tissue in Korean cattle.

• Journal of Microbiology and Biotechnology
• /
• 제12권3호
• /
• pp.417-422
• /
• 2002

Gene fusions were constructed by the transcriptional fusion of the dnaK promoter of pseudomonas sp. DJ-12 or E. coli to the lux or luc marker gene. The dnaKp-DJ::luxCDABE bioluminescent fusion in the biosensor using the Pseudomonas sp. DJ-12 dnaK promoter exhibited about 5-fold more extensive response to ethanol than that of dnaKp-EC::luxCDABE. The bioluminescent response of the dnaK-DJ::luc fusion to ethanol was much weaker than those of the other fusions. The biosensor harboring the dnaKp-DJ::luCDABE fusion was examined for its bioluminescence production based on exposure to aromatic compounds, such as biphenyl, 4-chlorobiphenyl (4CB), 4-hydroxybenzoate (4HBA), and catechol. In particular, the bioluminescence produced by the dnaKp-DJ::luxCDABE fusion was most sensitive to 1 mM biphenyl and 4CB when exposed for 80 min, and the responses were also very strong to other aromatics. Therefore, the biosensor bearing the dnaKp-DJ::luxCDABE fusion would appear to be the most useful for the detection of aromatics and other pollutants.

• 식물분류학회지
• /
• 제39권3호
• /
• pp.193-198
• /
• 2009

국내에 자생하는 Maackia속 2종(솔비나무, 다릅나무)의 염색체수 및 핵형을 분석하고 5S와 45S rDNAs를 이용한 bicolor FISH를 수행하였다. 솔비나무와 다릅나무의 체세포 염색체수는 동일하게 2n = 2x = 18로 관찰되었고, 염색체의 길이는 $3.58{\sim}5.82{\mu}m$이였다. 솔비나무의 염색체 조성은 2쌍의 중부 염색체(염색체 1과 7번), 4쌍의 차중부 염색체(염색체 4, 6, 8, 9번), 그리고 3쌍의 차단부 염색체(염색체 2, 3, 5번)로 확인되었다. 다릅나무의 염색체는 4번이 차단부 염색체, 7번이 차중부 염색체로 솔비나무와 차이를 보였으나 다른 염색체의 동원체 위치는 유사하게 관찰되었다. 5S와 45S rDNA를 이용한 FISH 결과, 45S rDNA 유전자는 솔비나무와 다릅나무에서 각각 1쌍으로 관찰되었고 2번 염색체의 2차 협착 부위에서 확인되었다. 5S rDNA유전자를 이용한 물리지도 작성에서는 두 종 사이를 구별할 수 있는 결과를 확인할 수 있었다. 솔비나무의 경우 염색체 7번과 8번의 동원체 부위에서 2쌍이 각각 관찰되었고, 다릅나무에서는 염색체 7번과 8번뿐만 아니라 3번과 4번 염색체에서도 관찰되어 모두 4쌍으로 확인되었다. 따라서, 5S rDNA유전자를 이용한 FISH방법을 통해 세포학적으로 두 종을 구분할 수 있었다.

• 한국작물학회지
• /
• 제53권2호
• /
• pp.131-136
• /
• 2008

With the development of diverse agricultures worldwide, biofortified rice noted for its preferable marketability and palatability plays an important role in the world's agricultural economics and rice breeding programs. In this report, several $M_5$ of T-DNA inserted lines derived from the donor cultivars, 'Hwayong' and 'Dongjin', were selected for high or low protein, high lipid and low amylose content, respectively. The coefficients and ranges of variation for the chemical constituents between $M_4$ and $M_5$ T-DNA inserted lines were evaluated in comparison with those of the donor varieties. Results indicated that T-DNA insertion might be an effective way to generate useful variations for chemical composition of rice grains which could be used for the development of biofortified rice cultivars.