• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.165-173
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• 1979

Recovery component for cell division in UV-irradiated E. coli B was detected with use of the cell extract of E. coli B/r which is a resistant mutant of E. coli B against UV-irradiation. The active substance was non-dialyzable and increased the activity by adding B-NAD remarkably. One more factor for increasing or promoting the restoration recognized was magnesium. Magnesium was effective to stabilze the substance in procedure of isolation. Two active substances were obtained from sucrose gradient centrifugation. One of them was recovred from the botton area and the other from top area just below below surface. the former was not stabilized by magnesium, while the latter stabilized the activity by it remarkably. The former which did not require magnesium was insensitive to protease and the latter which required magnesium was sensitive to it. Both were insensitive to RNase and DNase. Recovery ratio was doubled by using nitrogen gas than aeration in purification process. DNA-ligase less mutant was revealed same activity on it's recovery ratio with the parent strain of E. coli K-12. The active substance stimulating the filament cell may exist as a complex which is inactivated easily in the dissociated state ana requrie B-NAD or magnesium.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.192-198
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• 1990

To determine whether the muc region of pKM101 and its mutant pSL4 is sufficient for the expression of these phenotypes, muc regions of pKM101 and pSL4 were subcloned onto the highcopy number vector pKB354 and were selected the cloned pJB200 and pJB210. The recombinant plasmids pJB200 and pJB210 were introduced into umu $C36^{-}$ uvr $A6^{-}$ (TK610) strain and determined the protection effect and mutagenecity for UV and MMS. The protection effect and mutagenecity of umu $C36^{-}$ uvr $A6^{-}$ (TK610) were supressed by muc gene of the recombinant plasmids. The muc gene of pSL4 has higher effect than that of pKM101. The recombiant plasmid pJB210(inclued muc gene of pKM101) did not affect uv-mutagenesis in the $recA^{-}$ (JC2926) mutant.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.1
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• pp.1-7
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• 2015

Cornus walteri Wanger has been used in folk medicine in Korea. Ultraviolet (UV) irradiation has been known as a major cause of photo damage in skin. In the present study, research on how to cure damaged cells by UVB was conducted using an extract of Cornus walteri Wanger leaves (CWE), which was treated with an enzyme. CWE was applied to human dermal fibroblasts (HDFs) affected by UVB. UVB-irradiated HS68 cells showed increased caspase-3 activity, phosphorylation of p53, ${\gamma}H2AX$, cyclobutane pyrimidine dimers (CPDs) formation, and DNA fragmentation compared with non-irradiated cells. However, all these effects were inhibited by treatment with CWE for 12 h after UVB irradiation. Furthermore, CWE has proved not to cause primary skin irritation through the human patch test. Collectively, these results suggest that CWE could be a new potential candidate as photoprotective agent against UVB-induced cellular damage in HDFs.

• Journal of Life Science
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• v.24 no.2
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• pp.112-117
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• 2014

We investigated the effects of extracts from Rubus coreanus (RC) and Artemisia princeps var. orientalis (AP) on DNA damage response in ultraviolet B (UVB)-exposed HaCaT cells. Cell activity upon treatment for 24 h with RC or AP alone was similar to or greater than that of the nontreated control. When UVB-exposed cells were postincubated for 24 h in medium containing RC or AP, cell activity increased in a concentration-dependent manner. Nuclear fragmentation analysis showed that postincubation with RC or AP decreased UVB-induced apoptosis by about 20% and 15%, respectively, of that in cells postincubated with growth medium. When UVB-exposed cells were postincubated for 24 h in medium containing RC or AP, the level of cyclobutane pyrimidine dimer decreased in a concentration- dependent manner. Western blot analysis showed that treatment of cells not exposed to UVB with RC or AP alone did not significantly change the levels of phospho-p53 and GADD45 protein. Interestingly, when UVB-exposed cells were postincubated for 24 h in medium containing RC or AP, phospho-p53 and GADD45 levels decreased in a concentration dependent manner. Our results suggest that RC and AP extract assist the survival of UVB-exposed cells in parallel with a decrease in levels of UVB-induced DNA damage and damage-response proteins, such as p53 and GADD45.

• Journal of Nutrition and Health
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• v.21 no.1
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• pp.1-11
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• 1988

The effect of maternal low protein diets during gestation and lactation on growth and development of young rats was investigated. Pregnant and/or lactating rats were fed the diet containing 20% or 11.7%casein. DNA, RNA and total protein were determined in liver, muscle and brain of 21-day-old young rats and lipid contents and acetylcholinesterase activity in brain. Body and organ weight of young rats were measured. DNA, RNA and protein contents of liver, muscle and brain of young rats were less in maternal low protein group than that of control group. Total lipid and cholesterol contents in brain were less(p<0.01) in low protein group than that of control group than that of control group. And also brain acety;cholnesterase activity of low protein group was significantly (p<0.01) lower than those of control group, but their each organ weight ratios in relation to body weight was higher than that of control group. It could be suggested that the maternal low protein during gestation and lactation has influenced on cell number, cell size, protein content, brain lipid content and acetyl-cholinesterase activity of the offsprings.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.629-633
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• 1992

Caffeine이 랫드의 간조직에서 diethylnitrosamine(200mg/kg B.W., DEN)에 의해 유도되는 preneoplastic altered foci형성의 promotion단계에 미치는 효과를 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase(GST-P)-positive foci의 수는 caffeine 음수 $m{\ell}$당 2mg 병행투여군($3.10{\pm}2.74$) 및 1mg병행 투여군($5.86{\pm}2.83$) 모두에서 DEN 단독투여 대조군($11.55{\pm}5.82$)에 비하여 현저히 낮게 나타났으며 면적 또한 caffeine 2mg 병행투여군($0.13{\pm}0.11$), 1mg 병행투여군($0.21{\pm}0.12$)에서 DEN 단독투여 대조군($0.76{\pm}0.33$)에 비하여 유의성있는 낮은 수치가 관찰되었다. 간 세포배양에서 unscheduled DNA synthesis(UDS)는 DEN($250{\mu}g/m{\ell}$ of medium)단독처리군에 비하여 caffeine($200{\mu}g/m{\ell}$ of medium) 처리시 약 70% 감소하였다. 이러한 결과는 caffeine이 간암발생의 promotion단계에 작용하여 억제효과를 나타냄을 암시하며 이는 DNA회복의 억제와 관계됨을 알 수 있었다.

• Journal of Environmental Health Sciences
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• v.19 no.4
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• pp.59-66
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• 1993

The cellular toxicity and antitumor effects of bleomycin are thought to be occurred by formation of O$_2$-Fe$^{2+}$-bleomycin complexes that degrade DNA and release O$_2^-$ and $^{\cdot}$OH radicals. Hydroxyl radicals derived from hydrogen peroxide seem most likely to be involved in the various stages of carcinogenesis, and transition metals such as iron play a central role in activation of bleomycin and in formation of hydroxyl radicals. This study was performed to investigate whether treatment with ferrous sulfate increase chromosome aberration induced by bleomycin and hydrogen peroxide, and whether there is different repair mechanism for DNA damage induced by those chemicals. Treatment with 3AB, Ara C, during G$_1$ and post-treatment with caffeine, and Hu during G$_2$ increased the frequency of chromosome aberration induced by bleomycin but post-treatment with caffeine only did function that way when hydrogen peroxide was treated. When 6.6X 10$^{-7}$ M of bleomycin or 5.0X10$^{-5}$M of hydrogen peroxide were treated simultaneously with iron, the frequency of chromosome aberration was reduced, if compared with the results by bleomycin or hydrogen per oxide alone.

• The Journal of Korean Society for Radiation Therapy
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• v.4 no.1
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• pp.71-77
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• 1990

The present study was undertaken to investigate effects of ionizing radiation on DNA synthesis and chromosomal abnormality in cultured submandibular gland(SG) cells. SG cells from C57BL/6N Crj mice were cultured in Dulbecco's modified Eagle's medium (DME) supplemented with $10\%$ fetal bovine serum, antibiotics and fungizone. The cultured SG cells were irradiated with graded doses of gamma ray ($^{60}Co$) at a dose rate of 58.4rad/min. The effect of irradiation of $^{60}Co$ on DNA synthesis in cultured cells was evaluated by measuring the incorporation of 3H-TdR. Using conventional chromosome techniques and Giemsa staining methods, chromosomal abnormalities in cultured SG cells, induced by irradiation of $^{60}Co$ werw examined. Cytological observations were carried out by a light microscope with high resolving power. The results obtained were as follows : 1. DNA synthesis of SG cells was quantitatively dependent on a radiation dose compare to control. 2. A polyploids and few chromosome-type break, such as single and double breaks, deltions and triradial figures were more predominantly in irradiated SG cells than in control. This increase of chromosomal abnormality was in the proposition to the irradiation doses.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.87-94
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• 2015

High voltage pulsed electric fields (PEF) treatment is one of the more promising nonthermal technologies to fully or partially replace thermal processing. The objective of this research was to investigate the microbial inactivation mechanisms of PEF treatment in terms of intra- and extracellular changes in the cells. Saccharomyces cerevisae cells treated with PEF showed cellular membrane damage. This resulted in the leakage of UV-absorbing materials and intracelluar ions, which increased with increasing treatment time and electric fields strength. This indicates that PEF treatment causes cell death via membrane damage and physical rupture of cell walls. We further confirmed this by Phloxine B staining, a dye that accumulates in dead cells. Using scanning and transmission electron microscopy, we observed morphological changes as well as disrupted cytoplasmic membranes in PEF treated S. cerevisae cells. In addition, PEF treatment led to damaged chromosomal DNA in S. cerevisiae.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.192-196
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• 2005

The SNF2/SW12 family comprises proteins from a variety of species with in vivo functions, such as transcriptional regulation, maintenance of chromosome stability during mitosis, and various types of DNA repair. This study was shown the characterization of hrp2+ gene which was isolated by PCR amplification using the conserved domain of SNF2 motifs. Sequence analysis of hrp2+ gene showed striking evolutionary conservation among the SNF2 family of proteins. The transcript of hrp2+ gene was found to be a 4.7 kb as identified by Northern hybridization. To investigate the inducibility of hrp2+ gene, transcript levels were examined after treating the cells to various DNA damaging agents. The transcripts of hrp2+ were induced by UV-irradiation. But the transcripts were not induced by treatment of $ 0.25\%$ Methylmethane sulfonate (MMS). These results implied that the effects of damaging agents are complex and different regulatory pathways exist for the induction of this gene. Hrp2 protein was purified near homogeneity by combination of affinity chromatography. We tested the purified Hrp2 protein for the helicase activity in an oligonucleotide release assay. However we were unable to detect any helicase activity associated with the Hrp2 protein, indicating that the helicase motifs in Hrp2 are merely indicators of a broader DNA-dependent ATPase activity.