• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.265-272
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• 2006

Dental plaque, a biofilm consisting of more than 500 different bacterial species, is an etiological agent of human periodontal disease, It is therefore important to characterize interactions among periodontopathic microorganisms in order to understand the microbial pathogenesis of periodontal disease. Previous data have suggested a synergistic effect of tow major periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia in the periodontal lesion. In the present study, to better understand interaction between P. gingivalis and T. forsythia, the coaggregation activity between these bacteria was characterized. The coaggregation activity was observed by a direct visual assay by mixing equal amount (1 ${\times}$ $10^9$)of T. forsythia and P. gingivaJis cells. It was found that the first aggregates began to appear after 5-10 min, and that the large aggregates completely settled within 1 h. Electron and epifluorescence microscopic studies confirmed cell-cell contact between two bacteria. The heat treatment of P. gingivalis completely blocked the activity, suggesting an involvement of a heat-labile component of P. gingivalis in the interaction. On the other hand, heat treatment of T. forsythia significantly increased the coaggregation activity; the aggregates began to appear immediately. The coaggregation activity was inhibited by addition of protease, however carbohydrates did not inhibit the activity, suggesting that coaggregation is a protein-protein interaction. The results of this study suggest that coaggregation between P. gingivalis and T. forsythia is a result of cell-cell physical contact, and that coaggregation is mediated by a heat-labile component of P. gingivalis and T. forsythia component that can be activated on heat treatment.

• 한국물환경학회지
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• 제25권3호
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• pp.419-424
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• 2009

Characteristics of humic substances on the changes in dissolved organic matter (DOM) characteristics by biodegradation was investigated using three types of the artificial water samples composed of glucose and Suwannee River fulvic acid (SRFA). Some selected DOM characteristics including the specific UV absorbance (SUVA), the synchronous fluorescence spectra and the molecular weight (MW) were compared for the artificial water samples before and after 28-day microbial incubation. The changes of the DOM characteristics were minimal for SRFA during the incubation whereas they were significant for glucose. SUVA, dissolved organic carbon (DOC)-normalized fluorescence intensity, and MW values of glucose increased, suggesting that such labile organic compounds could be exclusively transformed into more humidified materials by biodegradation. For glucose-SRFA mixture, the selected DOM characteristics were greater than those estimated using the assumption that the individual changes of either glucose or SRFA are conservative for the mixture of the two materials. Our results suggest that the presence of humic substances (HS) may lead to the enhancement of the formation of refractory organic materials during biodegradation of labile compounds. Detailed analyses of size exclusion chromatography (SEC) revealed that the enhancement occurred for the DOM mixture with a MW range between 500 Da to 4000 Da.

• BMB Reports
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• 제38권2호
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• pp.225-231
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• 2005

Acid-labile subunit (ALS) is a component of the 150-kDa insulin-like growth factor-binding protein-3 (IGFBP-3) complex, which, by sequestering the majority of IGFs-I and -II and thereby prolonging the half-life of them in plasma, serves as a circulating reservoir of IGFs in mammalian species. A pGEX-2T plasmid and a baculovirus expression constructs harboring a coding sequence for glutathione-S transferase (GST)-porcine ALS (pALS) fusion protein were expressed in BL21(DE3) E. coli and Sf9 insect cells, respectively. The expressed protein was purified by glutathione or Ni-NTN affinity chromatography, followed by cleavage of the fusion protein using Factor Xa. In addition, pALS and hIGFBP-3 were also produced in small amounts in the Xenopus oocyte expression system which does not require any purification procedure. A 65-kDa pALS polypeptide was obtained following the prokaryotic expression and the enzymatic digestion, but biochemical characterization of this polypeptide was precluded because of an extremely low expression efficiency. The baculovirus-as well as Xenopus-expressed pALS exhibited the expected molecular mass of 85 kDa which was reduced into 75 and 65 kDa following deglycosylation of Asn-linked carbohydrates by Endo-F glycosidase, indicating that the expressed pALS was properly glycosylated. Moreover, irrespective of the source of pALS, the recombinant pALS and hIGFBP-3 formed a 130-kDa binary complex which could be immunoprecipitated by anti-hIGFBP-3 antibodies. Collectively, results indicate that an authentic pALS protein can be produced by the current expression systems.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.532-534
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• 2000

The inhibitory effects of different Bifidobacterium spp. on the growth of Helicobacter pylori (HP) were investigated. A significant suppression of HP growth occurred only when HP was inoculated onto a petri dish containing 0.1 mg/ml of Bifidobacterium spp. When HP was separately cultured with B. breve K-110, B. catenulatum K-309, B magnum K-311, B. magnum K-321, and B. cuniculi K-513, the urease activity was also inhibited by these Bifidobacterium spp. Therefore, it appears that these Bifidobacterium spp. excrete a heat-labile inhibitory component for HP growth into the culture medium. Although most organic acids produced by the Bifidobacterium spp. inhibited the growth of HP, the HP growth was not inhibited by the physiological concentrations of organic acids produced in bifidobacteria-cultured media. Accordingly, these results suggest that some Bifidobacterium spp. may produce antibiotic-like compounds (bacteriocins).

• Macromolecular Research
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• 제12권5호
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• pp.493-500
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• 2004

We have developed a novel method for patterning functional images in thin polymer films. The key materials we utilized for the imaging were dihydroxyanthraquinones protected with acid-labile tert-butoxycarbonyl (t-Boc) blocking groups. Among the tested compounds, 1,4-dihydroxyanthraquinone (quinizarin; 1) underwent the most drastic change in terms of its color and fluorescence upon protection. We prepared the t-Boc-protected quinizarin and polymers bearing the protected quinizarins as pendent groups. To investigate the possibility of a single-component imaging system, we synthesized a styrenic monomer 14 incorporating protected quinizarin and a maleimide derivative 15 bearing a photoacid generating group and subjected them to polymerization. Selective removal of the protecting groups of the quinizarin moieties in the exposed area using photolithographic techniques allowed regeneration of quinizarin and patterned fluorescence images in the polymer films.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2004년도 학술대회
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• pp.26-26
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• 2004

This study was conducted to evaluate the characteristics of dissolved orgamc matters based on their origins. The dissolved organic carbon(DOC) represents an index for dissolved organic matter and basically regarded as a source of organic pollution. The monthly variations and vertical profiles of dissolved organic carbon(DOC) in Kumoh reservoir were surveyed from May 2001 to April 2002. In addition, other areas such as river, reservoir, sewage and industrial wastewater were also surveyed in summer 2001. Kumoh reservoir was divided with depth into three layers .: epilimnion, metalimnion and hypolimnion. The proportion of total DOC(T-DOC) was classified by labile DOC(L-DOC) and refractory DOC(R-DOC) on the basis of long-term incubation. DOC of freshwater and Kumoh reservoir was ranged to be 1.6~4.1 mgC/L and 2.1~4.0 mgC/L, respectively. L-DOC accounted for 3~30% of DOC from watershed. Therefore, refractory dissolved organic carbon(R-DOC) was major component of DOC in the watershed. The decomposition rate(k) ranged from 0.008 $d^{-1}$ to 0.083 $d^{-1}$ in Kumoh reservoir. The highest decomposition rate(k) was observed at River Hoein III freshwater. Therefore, modified total organic carbon analyzer is needed to be applied for effective management of dissolved organic matter.

• Journal of the korean society of oceanography
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• 제32권3호
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• pp.103-111
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• 1997

Biogeochemical cycling of organic carbon is quantitatively partitioned in terms of 1) flux to the ocean bottom, 2) benthic utilization at or near the sediment-water interface, 3) remineralization and 4) burial within sediments, by making an independent determination for each component process from a single coastal site in Kwangyang Bay. The partitioning suggests that the benthic utilization at or near the sediment-water interface is the major mode of organic carbon cycling at the site. The benthic utilization takes 61.8% (441.6 gCm$^{-2}$ yr $^{-1}$) of the total near-bottem organic carbon flux, 714.6 gCm $^{-2}$yr$^{-1}$, and far exceeds the remineralization of organic carbon within the sediments which amounts only to 6% (41.24 gCm$^{-2}$yr$^{-1}$) of the total near-bottom flux. The residence time is about 1.6 years for the sedimentary metabolic organic carbon in the upper 45 cm. The dominant partitioning of the benthic utilization in the carbon budget suggests that most of labile organic carbons are consumed at or near the sediment-water interface and are left over to the sediment column by significantly diminished amounts.

• 농업과학연구
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• 제46권4호
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• pp.981-989
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• 2019

Coffee is a popular beverage worldwide, and the scale of consumption is growing rapidly. Many studies have shown that increased coffee consumption has various effects on human health, including beneficial effects on liver diseases, clinical type 2 diabetes, and Parkinson's disease. However, the influences of coffee or caffeine (a component of coffee) on the gut microbiota have not been examined in detail. Here, we tested whether caffeine could alter the antimicrobial activity of L. casei against E. coli. Interestingly, we found that treatment with 0.3 mg/mL caffeine increased the antimicrobial activity of L. casei against E. coli. This activity was not associated with the release of lactic acid but did appear to be related to a heat-labile factor present in the L. casei culture supernatant. Our analyses suggest that the putative antimicrobial factor found in the culture supernatant of L. casei treated with caffeine may be bacteriocin. Taken together, our results suggest that caffeine, which is an ingredient of coffee, increases the antimicrobial activity of L. casei against E. coli through the enhanced production of bacteriocin. These findings also suggest that coffee consumption affects the ability of beneficial bacteria to decrease pathogenic bacteria and/or prevent the progression of bacterial infection-associated diseases in the gut.

• Archives of Pharmacal Research
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• 제24권1호
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• pp.44-50
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• 2001

To search for cytotoxic components from Allium victoriallis , MTT assays on each extract and an isolated component, gitogenin 3-O-lycotetroside, were performed against cancer cell lines. Cytotoxicities of most extract were shown to be comparatively weak, though $IC_50$ values of $CHCl_3$fraction was found to be <31.3-368.4 $\mu\textrm{g}/ml$. From the incubated methanol extract at $36^{\circ}C, eleven kinds of organosulfuric flavours were predictable by CG-MS performance. The most abundant peak was revealed to be 2-vinyl-4H-1,3-dithiin(1) by its mass spectrum. Further, this extract showed significant cytotoxicities toward cancer cell lies. Silica gel column chromatography of the n-butanol fraction led to the isolation of gitogenin 3-O-lycotetroside (3) along with astragalin (4) and kaempferol 3, 4'-di-O-$\beta$-D-glycoside (5). This steroidal saponin exhibited significant cytotoxic activities ($IC_50$, 6.51-36.5 $\mu\textrm{g}/ml$) over several cancer cell lines. When compound 3 was incubated for 24 h with human intestinal bacteria, a major metabolite was produced and then isolated by silica gel column chromatography. By examining parent and prominent ion peak in FAB-MS spectrum of the metabolite, the structure was speculated not to be any of prosapogenins of 3, suggesting that spiroketal ring were labile to the bacterial reaction. These suggest that disulfides produced secondarily are the antitumor principles.

• 한국미생물·생명공학회지
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• 제8권1호
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• pp.1-8
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• 1980

쌀막걸리 제국중의 핵산관련물질 및 핵산분해효소의 소장을 시험하고 이들 조효소의 효소학적 성질에 대하여 실험한 결과는 다음과 같다. 1) 제국중 산하용성인은 약간 증가하였으나 총인은 그다지 변화가 없었다. 2) 제국중 AMP, IMP등은 약간 증가하였으나 ADP, ATP는 점차 감소하였다. 3) 시간의 경과에 따라 핵산분해효소의 활성은 증가하였다. 4) 국으로 부터 추출한 조효소액에서의 최적 pH는 대체로 RNase가 pH4.0~5.0, PDase와 PMase는 pH 4.0 이었다. 5) RNase와 PMase는 PH 4.0~5.0 부근에서 안정하였고 PDase는 pH4.0에서 대체로 안정하였다. 6) RNase, PDase, PMase의 최적온도는 모두 50~55$^{\circ}C$ 범위였다. 7) 세가지 효소의 열안정성은 RNase>PDase> PMase의 순이었고 특히 PMase는 열안정성이 낮아 7$0^{\circ}C$ 10분간 처리로서 거의 실활되었다. 8) C $u^{++}$, $Zn^{++}$은 RNase의 활성을 저해하였고, C $u^{++}$, NaF, $Na_2$HP $O_4$는 PDase, C $u^{++}$ NaF는 PMase의 활성을 저해하였다.