• 보존과학회지
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• 제36권1호
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• pp.15-27
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• 2020

The Main Hall of the Fengguo monastery in Yixian county, Liaoning province, China, is the best preserved and largest wooden Buddhist structure, typical of the Liao dynasty style, in China. However, some degradation to the timber frame of the Main Hall has been noted, and this is causing concern in terms of the long-term preservation of the structure. In this study, wooden pillars showing the degradation phenomena of whitening, for areas in contact with the stone floor, and extensive surface damage at higher locations(mostly above 1 m) have been examined. Samples taken from wooden pillar surfaces were analyzed using X-ray powder diffraction, Fourier-transform infrared spectroscopy(FTIR), ion chromatography, and pH measurements. With respect to the whitening phenomenon, we found inorganic calcium precipitates and oxalate ions, along with higher pH values. These symptoms indicated that chemical changes were taking place in response to alkaline conditions, suggesting that alkaline mixtures with calcium content in the foundations may be responsible. Regarding the upper surface-damaged areas, no valid evidence for chemical degradation was found using FTIR analysis, while damaged areas exhibited the presence of more bat guano-related materials than which were apparent in undamaged areas. The occurrence of this surface-damaged phenomenon has therefore been attributed to physical damage caused by bat activity over long periods of time.

• 공업화학
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• 제16권3호
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• pp.323-327
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• 2005

Pentachlorophenol (PCP)은 독성이 강한 발암성 물질로 미국환경청(Environmental Protection Agency, USA)이 정한 대표적인 환경호르몬이다. 본 연구에서는 종이 중에 함유된 극미량의 PCP 측정을 목적으로 하였다. 종이의 전처리는 고상추출법(SPE)을 이용하였고 분석을 위해 PCP를 유도체화시켜 gas chromatography/mass spectroscopy-selected ion monitoring (GC/MS-SIM)으로 분석하였다. GC/MS-SIM의 분석 결과 실릴화 PCP의 분석감도가 증가되었다. 본 실험에서는 실험군으로 사무용지와 벽지를 사용하였다.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1132-1138
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• 2006

Three types of xylanases (EC 3.2.1.8) were detected in the strain Aspergillus niger A-25, one of which, designated as XynIII, also displayed ${\beta}-(l,3-1,4)-glucanase$ (EC 3.2.1.73) activity, as determined by a zymogram analysis. XynIII was purified by ultrafiltration and ion-exchange chromatography methods. Its apparent molecular weight was about 27.9 kDa, as estimated by SDS-PAGE. The purified XynIII could hydrolyze birchwood xylan, oat spelt xylan, lichenin, and barley ${\beta}-glucan$, but not CMC, avicel cellulose, or soluble starch under the assay conditions in this study. The xylanase and ${\beta}-(l,3-1,4)-glucanase$ activities of XynIII both had a similar optimal pH and pH stability, as well as a similar optimal temperature and temperature stability. Moreover, the effects of metal ions on the two enzymatic activities were also similar. The overall hydrolytic rates of XynIII in different mixtures of xylan and lichenin coincided with those calculated using the Michaelis-Menten model when assuming the two substrates were competing for the same active site in the enzyme. Accordingly, the results indicated that XynIII is a novel bifunctional enzyme and its xylanase and ${\beta}-(l,3-1,4)-glucanase$ activities are catalyzed by the same active center.

• Applied Biological Chemistry
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• 제31권4호
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• pp.331-338
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• 1988

칡뿌리로 부터 칡뿌리 acetone분말을 제조하고 polyphenol oxidase를 추출, 정제하여 정제효소의 효소학적 특성을 검토하였다. 조효소는 DEAE-Cellulose, DEAE-Sephadex A-50, Sephadex G-100 column chromatography에 의하여 정제되었으며, 정제효소의 비활성은 94배, 정제수율은 45.4%이었다. 정제효소는 catechol 및 pyrogallol에 대하여 감한 친화성을 나타내었으며, km 값은 catechel을 기질로 하였을 때 16.67mM이었다. 작용 최적 pH는 7.5, 최적온도는 $50^{\circ}C$에서 가장 잘 작용하였고 1mM L-ascorbic acid, sodium bisulfite, EDTA, KCN 및 $Fe^{3+}$ 이온에 의하여 심한 저해를 나타내었으며, $Zn^{2+}$ 이온을 약 1.7배 정도의 활성을 증가시켰다. 조효소액을 전기영동하여 catechol로 활성염색 하였을 때 5개 isoenzyme이 확인되었으며 그 중 분자량 35,000의 것이 가장 강한 활성을 나타내었다.

• 분석과학
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• 제14권5호
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• pp.392-399
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• 2001

생물시료에 존재하는 휘발성 유기화합물 중 n-butylbenzene과 1,2-dibromo-3-chloropropane (DBCP)를 기체크로마토그래피/질량분석기-선택이온검색법에 의해 수행하였다. 시료 중 휘발성 유기화합물은 $100{\mu}m$ polydimethyl siloxane (PDMS) fiber를 사용하여 headspace solid phase microextractio (SPME) 및 purge & trap 방법에 의해 추출 및 비교하였다. SPME에 의한 회수율은 n-butylbenzene의 경우 85.8%, DBCP의 경우 92.4%로 나타났고 검출한계는 각각 $0.15{\mu}g/kg$, $0.05{\mu}g/kg$로 나타났다. 반면, purge & trap의 경우 회수율은 n-butylbenzene의 경우 115.2%, DBCP의 경우는 80.9%로 나타났고 검출한계는 각각 $0.04{\mu}g/kg$ 및 $0.70{\mu}g/kg$로 나타나 두 방법에 있어 국내에서 규제하는 검출한계측면에서 큰 차이는 없었다.

• 분석과학
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• 제24권4호
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• pp.298-303
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• 2011

셀레늄은 인체의 필수영양소로써 환경에서 또한 많은 관심을 가지고 있는 원소이다. 셀레늄은 자연수에서 주로 +4가의 selenite ($SeO_3^{-2}$)와 +6가의 selenate ($SeO_4^{2-}$)로 용해되어 있는데, 이들의 독성 및 화학적 성질은 매우 다르다. 따라서 자연수에서 셀레늄의 거동을 이해하기 위해서는 이들 두 화학종을 분리하는 것이 필요하다. 기존에 알려진 알루미나 충전 컬럼과 이온크로마토그래피를 이용한 selenite와 selenate의 분리방법들은 silicate 때문에 자연수에 직접 적용하기가 곤란하였다. 따라서 마그네타이트가 용액의 pH에 따라 selenite와 selenate를 흡착하는 정도가 다르므로 마그네타이트가 충전된 컬럼을 이용하여 이들의 분리를 수행한 결과, 성공적으로 분리할 수 있었다. 아울러 자연수에 존재하는 다른 음이온들 중에서 silicate는 selenite의 흡착을 방해하므로 silicate의 농도를 고려하여 충분한 양의 마그네타이트를 사용하여야만 한다.

• 한국수산과학회지
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• 제26권2호
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• pp.159-172
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• 1993

Collagenase existed in the internal organs of filefish Novoden modestrus was isolated with ammonium sulfate and was purified by ion exchange column chromatography with DEAE-Sephadex A-50 and gel filtration with Sephadex G-150. The activity of the purified enzyme was increased 92.4 folds than that of the crude one and the yield of the purified one was $10.9\%$. The optimum conditions showing the maximum activity of the crude enzyme to digest insoluble collagen(Type I) were $55^{\circ}C$ and pH 8.0, while those showing the maximum activity of the purified one were $55^{\circ}C$ and pH 7.75. However, the use of the crude enzyme for skinning of filefish was more profitable because the yield was 800 folds higher than that of the purified one and the cost was also able to economy. When hydrolysis for skinning of filefish was conducted with $0.3\%$(w/w) crude collagenase at $50^{\circ}C$ and pH 8.0 for 3hrs, there was some problem to cause a damage on muscle of the fish by heat. To solve such problem for the skinning, the hydrolysis at $18^{\circ}C$ for 4hrs with $0.3\%$ (w/w) crude enzyme after pretreated with 0.5M acetic acid for 10 min provided a good result for skinning of filefish.

• 한국미생물·생명공학회지
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• 제17권6호
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• pp.545-551
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• 1989

알칼리성 Bacillus속 8-16 균주의 내열ㆍ알칼리성단백질 분해효소를 정제하여 그 특성을 조사하였다. 본 균주의 알칼리성 protease를 아세톤침전, CM-셀룰로즈크로마토그래피, Sephadex G-100 및 G-75 젤 여과법으로 정제하였고 비활성이 37배되게 하여 단일단백질이 될 때까지 순수정제하였다. 이 효소는 7$0^{\circ}C$ pH 11에서 pH 12 사이에서 최대 활성을 나타냈고 6$0^{\circ}C$에서는 한시간 동안 안정하였다. 이 효소의 $K_m$치는 1.3mg/$m\ell$이며 분자량 33,000으로 추정된다. 또한 이 효소는 Cu$^{2+}$ 및 Mn$^{2+}$에 의해서 약간 활성화되고 Ag$^+$, Hg$^{2+}$ 및 PMSF에 의해서 저해되므로 활성부위에 serine기가 관여하는 것으로 추정된다.

• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1536-1543
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• 2013

Proteases produced by Xenorhabdus are known to play a significant role in virulence leading to insect mortality. The present study was undertaken to purify and characterize protease from Xenorhabdus indica, an endosymbiont of nematode Steinernema thermophilum, and to decipher its role in insect mortality and its efficacy to control Helicoverpa armigera. A set of 10 strains of Xenorhabdus isolated from different regions of India were screened for protease activity on the basis of zone of clearing on gelatin agar plates. One potent strain of Xenorhabdus indica was selected for the production of protease, and the highest production (1,552 U/ml) was observed at 15-18 h of incubation at $28^{\circ}C$ in soya casein digest broth. The extracellular protease was purified from culture supernatant using ammonium sulfate precipitation and ion-exchange chromatography. The enzyme was further characterized by SDS-PAGE and zymography, which confirmed the purity of the protein and its molecular mass was found to be ~52 kDa. Further MALDI-TOF/TOF analysis and effect of metal chelating agent 1,10-phenanthrolin study revealed the nature of the purified protease as a secreted alkaline metalloprotease. The bioefficacy of the purified protease was also tested against cotton bollworm (Helicoverpa armigera) and resulted in $67.9{\pm}0.64%$ mortality within one week. This purified protease has the potential to be developed as a natural insecticidal agent against a broad range of agriculturally important insects.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.367-372
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• 2013

Effects of the Epstein-Barr virus (EBV) on cellular protein expression are essential for viral pathogenesis. To characterize the cellular response to EBV infection, differential proteomes of gastric epithelial AGS cells were analyzed with two-dimensional gel electrophoresis (2-DE) followed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) and liquid chromatography electrospray/ionization ion trap (LC-ESI-IT) mass spectrometry identification. Mass spectrometry identified 9 altered cellular proteins, including 5 up-regulated and 4 down-regulated proteins after EBV infection. Notably 2-DE analysis revealed that EBV infection induced increased expression of heat shock cognate 71 kDa protein, actin cytoplasmic 1, pyridoxine-5'-phosphate oxidase, caspase 9, and t-complex protein 1 subunit alpha. In addition, EBV infection considerably suppressed those cellular proteins of zinc finger protein 2, cyclin-dependent kinase 2, macrophage-capping protein, and growth/differentiation factor 11. Furthermore, the differential expressional levels of partial proteins (cyclin-dependent kinase 2 and caspase 9) were confirmed by Western blot analysis.Thus, this work effectively provided useful protein-related information to facilitate further investigation of the mechanisms underlying EBV infection and pathogenesis.