• Fisheries and Aquatic Sciences
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• 제21권4호
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• pp.9.1-9.7
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• 2018

To establish a comprehensive management strategy, as part of the optimization of cultural practice for an oyster rack culture system, we used a numerical model to estimate the primary production in the waters on the eastern coast of Wando island, South Korea. The estimated primary production ranged from 17.12 to $1052.55mgC\;m^{-2}day^{-1}$ ($204.22{\pm}224.75mgC\;m^{-2}day^{-1}$ in average). Except for the times of peak phytoplankton blooms, the estimated primary production (PP) was consistently under $200mgC\;m^{-2}day^{-1}$, which is more similar to the value of PP measured off the western coast of South Korea than the southern coast. No clear relationship was observed between nitrogen content and rainfall with the exception of heavy rainfall events, indicating that precipitation might not be the main source of nutrients in these waters. No clear influence was observed from Doam tidal discharge, located 24 km north from these waters due to main tide comes in this area from the channel between Gunwe-myeon in Wando island and Pukpyeong-myeon in Haenam-gun. Because of the shallow water depth and strong tidal current, resuspension of sediments, which causes an input of nitrogen into the system, could be easily caused by even mild wind and the infrequent passing of ships. Microscopic examination of the phytoplankton composition showed additional contribution of benthic species such as Paralia sulcata into the waters, which increase the productivity of oyster farms in the waters. The availability of nitrate and phosphate for primary production was temporarily limited throughout most of the spring and autumn blooming season.

• 대기
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• 제26권2호
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• pp.243-256
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• 2016

Total number concentration of aerosols larger than 10 nm ($N_{CN10}$), 3 nm ($N_{CN3}$), and cloud condensation nuclei ($N_{CCN}$) were measured during four different ship cruises over the Yellow Sea. Average values of $N_{CN10}$ and $N_{CCN}$ at 0.6% supersaturation were 6914 and $3353cm^{-3}$, respectively, and the minimum value of $N_{CN10}$ was $2000cm^{-3}$, suggesting significant anthropogenic influence even at relatively clean marine environment. Although $N_{CN10}$ and $N_{CN3}$ increased near the coast due to anthropogenic influence, $N_{CCN}$ was relatively constant and therefore $N_{CCN}/N_{CN10}$ ratio tended to decrease, suggesting that coastal aerosols were relatively less hygroscopic. In general $N_{CN10}$, $N_{CN3}$, and $N_{CCN}$ during the cruises seemed to be significantly influenced by wet scavenging effects (e.g. fog) and boundary layer height variation. Only one new particle formation (NPF) event was observed during the measurement period. Interestingly, the NPF event occurred during a dust storm event and spatial scale of the NPF event was estimated to be larger than 100 km. These results demonstrate that aerosol and CCN concentration over the Yellow Sea can vary due to various different factors.

• Archives of Pharmacal Research
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• 제22권5호
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• pp.464-473
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• 1999

Regulation of phosphcholine-hydrolyzing phosphatase (phosphocholine-phosphatase) activity, purified from bovine brain, was examined under physiological conditions. Various endogenous phosphomonoesters, which were utilized as substrate, inhibited the phosphocoline-phosphatase activity competitively (Ki 5.5-$82.0 {\mu}M$); among phosphomonoesters tested, there was a similar order of capability between the binding affinity of substrate and the inhibitory potency. In addition, phosphate ions also inhibited the phosphatase activity competitively with a Ki value of approximately $16{\mu}M$. Although leucine or theophylline inhibited the phosphatase activity at pH 9.0, their inhibitory action decreased greatly at pH 7.4. The pH-Km and pH-Vm profiles indicate that ionizable amino acids are involved in substrate binding as well as catalysis, alluding that the phosphatase activity may be highly dependent on the intracellular pH. Amino acid modification study supports the existence of tyrosine, arginine or lysine residue in the active site, and the participation of tyrosine residue in the catalytic action may e suggested positively for the susceptibility to the action of tetranitromethane or HOl-generator. Separately, the oxidative inactivation of phosphocholine-phosphatase activity was investigated. Of oxidants tested, HOONO, HOCl, HOl and $ascorbate/Cu^{2+}$ system were effective to inactivate the phosphatase activity. Noteworthy, a remarkable inativation was accomplished by $30{\mu}M$ HOCl in combination with 1 mM Kl. Inaddition, $Cu^{2+}(3{\mu}M) $in combination with ascorbate at concentrations as low as 0.1-0.3 mM reduced the phosphatase activity to a great extent. From these results, it is proposed that the phosphocholine-phosphatase activity may be regulated endogenously and susceptible to the various oxidant system in vivo.

• Journal of Ginseng Research
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• 제40권4호
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• pp.395-399
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• 2016

Background: Korean ginseng (Panax ginseng) is one of the most important medicinal plants in the Orient. Among nine cultivars of P. ginseng, Chunpoong commands a much greater market value and has been planted widely in Korea. Chunpoong has superior quality "Chunsam" ($1^{st}$ grade ginseng) when made into red ginseng. Methods: A rapid and reliable method for discriminating the Chunpoong cultivar was developed by exploiting a single nucleotide polymorphism (SNP) in the auxin repressed protein gene of nine Korean ginseng cultivars using specific primers. Results: An SNP was detected between Chunpoong and other cultivars, and modified allele-specific primers were designed from this SNP site to specifically identify the Chunpoong cultivar and P. quinquefolius via multiplex polymerase chain reaction (PCR). Conclusion: These results suggest that great impact to prevent authentication of precise Chunpoong and other cultivars using the auxin repressed protein gene. We therefore present an effective method for the authentication of the Chunpoong cultivar of P. ginseng and P. quinquefolius.

• 한국철도학회논문집
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• 제12권3호
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• pp.348-356
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• 2009

본 연구의 목적은 SP 조사를 통해 화물별 DMT 효용함수 추정에 목적을 두고 있다. 추정된 효용함수는 화물별 OD 자료를 바탕으로 DMT 수요예측에 기초자료로 이용될 수 있다. 설문조사에서는 컨테이너와 위험물을 다루고 있는 업체와 철강운송 업체 중 연안 해운을 하고 있지 않은 운송업체를 대상으로 철도운송, 도로운송, DMT, 이렇게 세 가지의 선택대안을 사용하였다. 선택상황은 품목별/운송방향별로 가상 상황을 설정하였고 선정한 주요 화물품목은 컨테이너, 철강, 위험물이다. 또한 각각의 화물품목들에 대한 운송거리별 운송수단 선택모형은 통계적으로 다르지 않은 것으로 분석되었기 때문에 거리별(장거리, 중거리, 단거리)로 모형을 구축하지 않고 가장 물동량이 많은 장거 리(300km 이상)의 경우에 한해 화물별로 모형구축을 시도하였다. 사용할 속성변수로는 운송시간, 운송비용 그리고 신뢰성을 선정하였다. 수준 수는 일반적으로 가장 많이 사용되는 3수준으로 정하였으며 수준 값은 기준 값을 중심으로 +10%와 -20%로 정하였다.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1287-1291
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• 2009

시안화물을 포름아미드로 변환시키는 nitrilase의 일종인 시안 수화효소 (cyanide hydratase, CHT) 를 진균류인 Neurospora crassa 와 Aspergillus nidulans로부터 유전자 조작을 통하여 His에 태그 또는 언태그된 형태로 대장균에 형질변환시켜 발현하였다. 발현된 효소를 고정 metal affinity chromatography로 정제하였다. 정제된 효소들의 pH 안정성, 동력학적 매개변수의 값을 검토하였다. 실험 결과 N. crassa 의 CHT가 50% 정도 더 넓은 pH 안정 범위를 가졌고 3배 가량 turnover rate도 높았다. 반면 A. nidulans CHT의 Km 값 (효소포화 용량)이 N. crassa CHT보다 더 크게 나타났다. 두 진균류에서 CHT의 유도발현은 질소성분과 상관없이 KCN에 의해 가능하였으며, 생분해 실험결과 N. crassa CHT에 의해 최대 82%/h의 시안분해가 가능하였다.

• Journal of Plant Biology
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• 제35권1호
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• pp.91-95
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• 1992

저온처리($4^{\circ}C$)하에서 보리(Hordeum vulgare L. cv. Chalssal) 유식물 잎의 당함량과 sucrosephosphate synthase, sucrose synthease, invertase의 활성의 변화를 측정하고, 또한 acid invertase의 성질을 조사하였다. 저온처리 3일만에 보리유식물의 환원당과 설탕의 함량은 1.3배 및 2.4배로 각각 증가하였다. 그리고 sucrosephosphate synthase, sucrose synthase 및 alkaline invertase의 활성에는 별다른 변화가 없었으나 acid invertase의 활성은 크게 저하하였다. Ammonium sulfate 분획과 DEAE-Sephacel 컬럼으로 부분정제한 acid invertase에서, 설탕에 대한 Km은 9.5mM이고 최적 pH는 5.5, 최적온도는 $35^{\circ}C$로 측정되었다. 여러 가지 기질에 대한 특이성을 조사한 결과 본 효소는 ${\beta}-fructosidase로$ 추정할 수 있었으며, 효소의 분자량은 Sephadex G-200 컬럼 크로마토그래피로 산출하였을 때 63 Kd이었다.

• Journal of Microbiology
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• 제44권2호
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• pp.185-191
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• 2006

The photosynthetic bacterium, Rhodospirillum rubrum S1, when grown under anaerobic conditions, generated three different types of catalases. In this study, we purified and characterized the highest molecular weight catalase from the three catalases. The total specific catalase activity of the crude cell extracts was 88 U/mg. After the completion of the final purification step, the specific activity of the purified catalase was 1,256 U/mg. The purified catalase evidenced an estimated molecular mass of 318 kDa, consisting of four identical subunits, each of 79 kDa. The purified enzyme exhibited an apparent Km value of 30.4 mM and a Vmax of 2,564 U against hydrogen peroxide. The enzyme also exhibited a broad optimal pH $(5.0{\sim}9.0)$, and remained stable over a broad temperature range $(20^{\circ}C{\sim}60^{\circ}C)$. It maintained 90% activity against organic solvents (ethanol/chloroform) known hydroperoxidase inhibitors, and exhibited no detectable peroxidase activity. The catalase activity of the purified enzyme was reduced to 19 % of full activity as the result of the administration of 10 mM 3-amino-1,2,4-triazole, a heme-containing catalase inhibitor. Sodium cyanide, sodium azide, and hydroxylamine, all of which are known heme protein inhibitors, inhibited catalase activity by 50 % at concentrations of $11.5{\mu}M,\;0.52{\mu}M,\;and\;0.11{\mu}M$, respectively. In accordance with these findings, the enzyme was identified as a type of monofunctional catalase.

• Applied Biological Chemistry
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• 제26권1호
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• pp.41-46
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• 1983

송이버섯[Tricholoma matsutake(S. Ito et Imai);Sing.]에서 polyphenol oxidase 조효소액(粗酵素液)을 추출(抽出), 그 성질(性質)을 조사(調査)하여 다음과 같은 결과(結果)를 얻었다. Trihydroxyphenol류(類)와 o-diphenol류(類)에 활성(活性)을 보였고 이들중 pyrogaroll이 최고활성(最高活性)을 보였으며 m-diphenol, p-diphenol 그리고 monophenol류(類)에서는 활성(活性)을 보이지 않았다. 최적(最適) pH는 4.0 부근이었고, 최적온도(最適溫度)는 $45{\sim}55^{\circ}C$였으며, 효소(酵素)의 활성(活性)이 $70^{\circ}C$에서 2분(分) 가열(加熱)로 완전(完全)히 실활(失活)되었다. $Cu^{++}$, $Fe^{++}$ 및 $Mg^{++}$은 $10^{-1}mM$이상(以上) 농도(濃度)에서는 효소력(酵素力)이 증가(增加)되었으나, 그 이상(以上)의 농도(濃度)에서는 오히려 저하(低下)되었다. 저해제(沮害劑)로는 Na-DETC, L-ascorbic acid, L-cysteine 및 NaCl이 양호(良好)하였다. pyrogaroll에 대한 km치(値)는 0.88mM이었다.

• Journal of Microbiology and Biotechnology
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• 제3권1호
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• pp.31-38
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• 1993

A bacterial strain KY-l isolated from sewage was able to produce an extracellular agarase(agarose 4-glycanohydrolase. EC 3.2.1.81). The strain KY-1 was identified as Cytophaga fermentans subsp. agarovorans based on its morphological and physiological characteristics. The agarase was purified by ammonium sulfate precipitation followed by DEAE-Sephadex A-50. Bio-Gel P-100. and CM-Cellulose column chromatography. The molecular weight of the purified enzyme was 24 kDa by SDS-polyacrylamide gel electrophoresis. The optimum temperature and pH for the enzyme activity were 30^{circ}C and 7.5, respectively. The enzyme activity was significantly inhibited in the presence of 0.1 mM $HgCl_2$. whereas it was elevated 3 times by $MnSO_4$ at 1 mM concentration. The Km value and Vmax were 16.67 mg/ml and 3.77 unit/ml.min. The agarase gene was cloned into Escherichia coli MC1061 using the plasmid vector pBR322. A 1.4 Kb DNA fragment of PstI-digested chromosomal DNA of C. fermentans KY-l was inserted into the PstI site of pBR322. expressed in the E. coli. and up to 60% of the total enzyme was extracellularly secreted. Enzymatic properties of the extracellular agarases produced by both the transformant and the donor were very similar in terms of optimal pH and temperature.