• 분석과학
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• 제7권3호
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• pp.271-276
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• 1994

셀룰로스에 대한 +2와 +3가 금속이온들의 흡착성을 최적 조건에서 실험하였는데, +2가 금속이온으로 Cu(II), Zn(II), Pb(II) 및 Cd(II) 이온을 선택하였으며, +3가 금속이온으로 Cr(III)와 Fe(III) 이온을 선택하여 실험하였다. 셀룰로스에 대한 흡착능을 증대시키기 위하여 셀룰로스를 2M NaOH로 처리하여 Na-셀룰로스를 제소하였다. 셀룰로스에 대한 금속이온 흡착능은 매우 작아서 고분자 흡착제로서의 효과가 없었으나 Na-셀룰로스는 고분자 흡착제로서 매우 효과적이었다. Na-셀룰로스에 대한 금속이온들의 흡착은 뱃치법으로 실험하였다. 최적 조건에서 Na-셀룰로스에 대한 금속이온들의 흡착은 +2가 금속이온들은 1:2, +3가 금속이온들은 1:3의 흡착비로 흡착하는 이온교환 흡착이었다. Na-셀룰로스에 대한 금속이온들의 흡착엔탈피는 -18kcal/mol 정도였으며, carboxymethylcellulose(CMC)와 Dowex 50W-X8 수지와 비교 실험한 결과, Na-셀룰로스에 대한 금속이온들은 흡착은 이온교환흡착으로, 비슷한 작용기를 가지고 있는 CMC와 비슷한 흡착엔탈피를 보였다.

• Fisheries and Aquatic Sciences
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• 제19권4호
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• pp.21.1-21.11
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• 2016

Background: The evaluation of suitable reference genes as normalization controls is a prerequisite requirement for launching quantitative reverse transcription-PCR (RT-qPCR)-based expression study. In order to select the stable reference genes in abalone Haliotis discus hannai tissues (gill and hepatopancreas) under heavy metal exposure conditions (Cu, Zn, and Cd), 12 potential candidate housekeeping genes were subjected to expression stability based on the comprehensive ranking while integrating four different statistical algorithms (geNorm, NormFinder, BestKeeper, and ${\Delta}CT$ method). Results: Expression stability in the gill subset was determined as RPL7 > RPL8 > ACTB > RPL3 > PPIB > RPL7A > EF1A > RPL4 > GAPDH > RPL5 > UBE2 > B-TU. On the other hand, the ranking in the subset for hepatopancreas was RPL7 > RPL3 > RPL8 > ACTB > RPL4 > EF1A > RPL5 > RPL7A > B-TU > UBE2 > PPIB > GAPDH. The pairwise variation assessed by the geNorm program indicates that two reference genes could be sufficient for accurate normalization in both gill and hepatopancreas subsets. Overall, both gill and hepatopancreas subsets recommended ribosomal protein genes (particularly RPL7) as stable references, whereas traditional housekeepers such as ${\beta}-tubulin$ (B-TU) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were ranked as unstable genes. The validation of reference gene selection was confirmed with the quantitative assay of MT transcripts. Conclusions: The present analysis showed the importance of validating reference genes with multiple algorithmic approaches to select genes that are truly stable. Our results indicate that expression stability of a given reference gene could not always have consensus across tissue types. The data from this study could be a good guide for the future design of RT-qPCR studies with respect to metal regulation/detoxification and other related physiologies in this abalone species.

• 한국대기환경학회지
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• 제27권3호
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• pp.347-357
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• 2011

The TSP aerosols were collected at Gosan site of Jeju Island between 2003 and 2007, and their aerosol components were analyzed to examine the variations of chemical compositions with the corresponding pathways of inflowing air parcels. According to the comparison of seasonal aerosol compositions, the soil-originated components showed remarkably high concentrations during spring season. On the other hand, the concentrations of anthropogenic components were somewhat high in spring and summer seasons, but low in fall season. Based on the comparison of TSP compositions in relation to the pathways of inflowing air mass, the concentrations of anthropogenic components (nss-$SO_4^{2-}$, S, $NO_3^-$), soil-originated components (nss-$Ca^{2+}$, Al, Fe, Ca), and the heavy metals (e,g., Mn, Zn, Cr, Pb, Cu, Cd, etc.) have relatively increased with the air mass moving from China continent into Jeju area. Meanwhile, the marine-originated components showed an increasing trend with the air mass coming from North Pacific Ocean. In the seasonal and sectional comparison, the nss-$SO_4^{2-}$, $NO_3^-$, nss-$Ca^{2+}$, and Al showed comparatively high concentrations when the air mass moved from China continent during all seasons. Especially, the $NO_3^-$, nss-$Ca^{2+}$, and Al concentrations were somewhat high when the air mass moved from Korean Peninsula during summer season. It was also recognized that the Na+ concentration were high, when the air mass moved from Pacific Ocean through all seasons.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.873-880
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• 2009

A novel xylanase gene, Kxyn, was cloned from Kocuria sp. Mn22, a bacteria isolated from the deep sea of the east Pacific. Kxyn consists of 1,170 bp and encodes a protein of 390 amino acids that shows the highest identity (63%) with a xylanase from Thermohifida fusca YX. The mature protein with a molecular mass of approximately 40 kDa was expressed in Escherichia coli BL21 (DE3). The recombinant Kxyn displayed its maximum activity at $55^{\circ}C$ and at pH 8.5. The $K_m,\;V_{max}$, and $k_{cat}$ values of Kxyn for birchwood xylan were 5.4 mg/ml, $272{\mu}mol/min{\cdot}mg$, and 185.1/s, respectively. Kxyn hydrolyzed birchwood xylan to produce xylobiose and xylotriose as the predominant products. The activity of Kxyn was not affected by $Ca^{2+},\;Mg^{2+},\;Na^+,\;K^+$, ${\beta}$-mercaptoethanol, DTT, or SDS, but was strongly inhibited by $Hg^{2+},\;Cu^{2+},Zn^{2+}$, and $Pb^{2+}$. It was stable over a wide pH range, retaining more than 80% activity after overnight incubation at pH 7.5-12. Kxyn is a cellulase-free xylanase. Therefore, these properties make it a candidate for various industrial applications.

• Ocean and Polar Research
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• 제25권1호
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• pp.21-30
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• 2003

Seasonal fluctuations of physico-chemical and biological aspects of the environment were studied in Vladivostok harbour (Golden Horn Bay, the East Sea/Sea of Japan). The benthic community structure was described with a focus on size-spectra (bacteria, meio- and macrofauna) related with the chemical environment and chemical fluxes in sediment and to reveal their possible ecological role in the process of bioremediation of the environment. Samples from two sites with different concentrations of heavy metals (Fe, Zn, Cu, Pb, Mn, Cr, Ni Cd, Co) and petroleum hydrocarbon were assessed by a number of methods. These included plate counts of culturable bacteria, observation through a scanning electron (SEM) and transmission electron microscope (TEM). These approaches were complemented with microscopic assessments of the diversity of the benthic community. The specific communities had a limited number of species, tolerant to abnormally high levels of toxic compounds. The dominant species were presented by several sho.1-lived small polychaetes (Capitella capitata) and nematodes (Oncholaimium ramosum). The highest population density was recorded in microbenthos, in various diatoms, various physiological groups of bacteria which participate in biomineralization: marine heterotrophic bacteria, which oxidized oil, black oil in addition to groups resistant to heavy metals. They have the entire set of mechanisms for neutralizing the negative effect of those compounds, forming the detrital food web and biogeochemical circulation of material in sediments, which results in the biological self-recycling of sea basins. Macro- and meiobenthic organisms were more sensitive to a greater extent of $H_2S$ and petroleum hydrocarbons than to metal content, but the within-site rankings were the same as those achieved for microbiological analyses.

• Ocean and Polar Research
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• 제25권1호
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• pp.31-40
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• 2003

In August-September 2001, 15 samples of bottom sediments were collected in the inner, middle and open parts of Amursky Bay near Vladivostok, Russia, and barfin plaice Pleuronectes pinnifasciatus was sampled from the inner and the middle locations of the bay. In the sediments from all three sites elevated concentrations of several heavy metals, i.e. Zn ($102-115{\mu}/g$ dry weight), Ni $(70-73{\mu}g/g)$ and Cu $(27-35{\mu}g/g)$ were discovered. The contents of oil hydrocarbons were very close to or slightly higher than the maximal normal environmental background level, $100{\mu}g/g$ dry weight. The sediments contained negligible amounts of hexachlorocyclohexane, while DDT concentrations were quite high (1.7-16.3ng/g dry weight). Generally, there were no substantial differences in the pollution levels of the locations studied and our results resembled those reported for Amursky Bay in the 1990s. Surprisingly, in 2001 'fiesh' DDT comprised 70-85% of the total DDT content in sediment from all the locations studied. In fish liver total DDTs concentrations were 212.8 and 122.54 ng/g wet weight for the inner and the middle locations, respectively, and 'fresh' DDT comprised 35 and 64% of DDTs, respectively. These results provide evidence of recent input of DDT from an unknown source into the ecosystem of Amursky Bay. Histopathological changes revealed in the plaice liver (vacuolization of hepatocytes, coagulative necrosis of hepatocytes, inflammatory reaction, and necrosis of epithelial cells of bile ducts) are probably connected with an intensive metabolism of DDT in the fish organism. No histological and histomorphometric differences were found in the state of the interrenal tissue. Similar condition of the liver and the interrenal tissue in barfin plaice sampled from the inner and the middle locations of Amursky Bay may be explained by the absence of great differences in the pollution levels of these sites.

• 한국토양비료학회지
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• 제43권4호
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• pp.478-483
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• 2010

전라북도 장수군 오미자 과원을 대상으로 토양의 이 화학적 특성을 조사하여 오미자의 품질향상, 수량증대 및 유해물질 종합관리 시스템 구축을 위한 기초조사를 수행하였다. 오미자 재배과원 토양은 대부분 양질사토였으며, 토양입단화도는 약 33.12%로 입단의 발달이 부족한 상태였으며, 토양공극율은 약 60% 수준으로 적당한 것으로 나타났다. 토양 pH는 평균 5.51이었으며, 양이온교환용량은 평균 4.11 $cmol_c\;kg^{-1}$으로 매우 낮게 나타났다. 식물영양성분은 적정 수준으로 유지되고 있었으나, 장수군 오미자 재배지 토양의 이화학적 특성 개량을 위해서는 유기물 및 석회처리 등의 토양관리가 필요한 것으로 나타났다. 조사대상 중금속의 함량은 자연함유량 수준으로 중금속 오염으로 인한 작물 안정성은 확보된 것으로 조사되었다.

• 미생물학회지
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• 제31권3호
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• pp.230-236
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• 1993

Micrococcus luteus 가 생산하는 isocitrate lyase 의 효소단백질을 ammonium sulfate precipitation, DEAE-cellulose, DEAE-sephacel, 1차 Sephadex G-200, 2 차 Sephadex G-200 column chromatography 과정을 통하여 분리 정제하였으며 정제된 효소의 분자량과 효소학적 특성을 조사하였다. 정제된 isocitrate lyase 는 상기 정제 과정을 통하여 10.2%의 회수율과 38.8 의 정제도를 나타내었으며, 전기영동시 단일밴드를 얻을 수 있었고, SDS-PAGE 에 의해 측정된 분자량을 약 60,000이며 1개의 subunit 로 나타났다. 본 효소의 최적 pH 는 7.5이었으며, 최적 온도는 $40^{\circ}C$ 부근이었고 $45^{\circ}C$까지는 안정하였다. 2가 금속염의 첨가시$ Mg^{2+}$ 를 제외한 다른 금속이온들은 효소활성을 저해하는 것으로 나타났으며 $Mg^{2+}$의 농도는 5 mM 에서 최대활성을 나타내었다. 또한 기질인 DL-isocitrate 의 $K_{m}$ 치는 0.95 mM 로 나타났으며, thiol 화합물의 첨가시 cysteine 은 1mM, glutathione과 $\beta$-mercaptoethanol 은 5 mM 의 농도에서 효소활성이 최대에 달하였다.

• Journal of Microbiology
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• 제35권2호
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• pp.109-116
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• 1997

An extracellular proteinase of Candida albicans was purified by a combination of 0~75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephacryl S-200 HR molecular sieve chromatography. Its mlecular weight was approximately 41 kDa on SDS-PAGE and isoelectric point was 4.4. The enzyme was inhibited by pepstain A. Optimum enzyme activity ranged from pH 2.0 to 3.5 with its maximum at pH 2.5 and a temperature of 45$^{\circ}C$. The addition of divalent cations, $Ca^{2+}$, Zn$^{2+}$ and $Mg^{2+}$, resulted in no significant inhibition of enzymatic activity. However, some inhibitory effects were observed by Fe$^{2+}$, Ag$^{2+}$ and Cu$^{2+}$. With BSA as substrate, an apparent $K_m$ was determined to be 7$\times$10$^{-7}$ M and $K_i$, using pepstatin A as an inhibitor, was 8.05$\times$10$^{-8}$ M. N-terminal amino acid sequence was QAVPVTLXNEQ. Degradation of BSA and fibronectin was shown but not collagen, hemoglobin, immunoglobulin G, or lysozyme. The enzyme preferred peptides with Glu and Leu at the P$_1$ position, but the enzyme activity was highly reduced when the P$_2$ position was phe or pro. This enzyme showed antigenicity against sera of patients with candidiasis.

• 한국환경과학회지
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• 제16권12호
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• pp.1337-1343
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• 2007

The aim of this study was to isolate chicken feather-degrading bacteria with high keratinolytic activity and to investigate cultural conditions affecting keratinolytic enzyme production by a selected isolate. A chicken feather-degrading bacterial strain CH3 was isolated from poultry wastes. Isolate CH3 degraded whole chicken feather completely within 3 days. On the basis of phenotypical and 16S rDNA studies, isolate CH3 was identified as Bacillus thuringiensis CH3. This strain is the first B. thuringiensis described as a feather degrader. The bacterium grew with an optimum at pH 8.0 and $37^{\circ}C$, where maximum keratinolytic activity was also observed. The composition of optimal medium for keratinolytic enzyme production was feather 0.1%, sucrose 0.7%, casein 0.3%, $K_2HPO_4$ 0.03%, $KH_2PO_4$ 0.04%, $MgCl_2$ 0.01% and NaCl 0.05%, respectively. The keratinolytic enzyme had a pH and temperature optima 9.0 and $45^{\circ}C$, respectively. The keratinolytic activity was inhibited ethylenediaminetetraacetic acid, phenylmethylsulfonyl fluoride, and metal ions like $Hg^{2+},\;Cu^{2+}\;and\;Zn^{2+}$. The enzyme activated by $Fe^{2+}$, dithiothreitol and 2-mercaptoethanol.