• The Korean Journal of Physiology and Pharmacology
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• 제1권5호
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• pp.495-504
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• 1997

Water transport is mediated by two distinct pathways, diffusional and channel-mediated water transport. The first molecular water channel was identified from human erythrocytes in 1992. Genetically-related proteins from other mammalian tissues have subsequently been identified to transport water, and the group is referred to as th "Aquaporins". Aquaporin-4 (AQP4) is most abundant in the brain, which may be involved in CSF reabsorption and osmoregulation. However, ontogeny and regulatory mechanisms of AQP4 channels have not been reported. Northern blot analysis showed that AQP4 mRNA began to be expressed in the brain just before birth and that its expression gradually increased by PN7 and then decreased at adult level. AQP4 was expressed predominantly in the ependymal cells of ventricles in newborn rats. And then its expression decreased in ependymal cells and increased gradually in other regions including supraoptic and paraventricular nuclei. AQP4 is also expressed in the subfornical organ, in which the expression level is not changed after birth. Cryogenic brain injury did not affect expression of AQP4 mRNA, while ischemic brain injury decreased it. Osmotic water permeability of AQP4 channel expressed in Xenopus oocytes was inhibited by the pretreatment of BAPTA/AM and calmidazolium, a $Ca^{2+}/Calmodulin$ kinase inhibitor, in a dose-dependent manner. These results indicate that the expression and the function of AQP4 channel are regulated by developmental processes and various pathophysiological conditions. These results will contribute to the understanding of fluid balance in the central nervous system and the osmoregulatory mechanisms of the body.

• Genomics & Informatics
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• 제2권2호
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• pp.67-74
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• 2004

Cells consistently face stressful conditions, which cause them to modulate a variety of intracellular processes and adapt to these environmental changes via regulation of gene expression. Hyperosmotic and oxidative stresses are significant stressors that induce cellular damage, and finally cell death. In this study, oligonucleotide microarrays were employed to investigate mRNA level changes in cells exposed to hyperosmotic or oxidative conditions. In addition, since heat shock protein 70 (HSP70) is one of the most inducible stress proteins and plays pivotal role to protect cells against stressful condition, we performed microarray analysis in HSP70-overexpressing cells to identify the genes expressed in a HSP70-dependent manner. Under hyperosmotic or oxidative stress conditions, a variety of genes showed altered expression. Down­regulation of protein phosphatase1 beta (PP1 beta) and sphingosine-1-phosphate phosphatase 1 (SPPase1) was detected in both stress conditions. Microarray analysis of HSP70-overexpressing cells demonstrated that diverse mRNA species depend on the level of cellular HSP70. Genes encoding Iysyl oxidase, thrombospondin 1, and procollagen displayed altered expression in all tested conditions. The results of this study will be useful to construct networks of stress response genes.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.522-525
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• 2002

A very rapid and efficient separation technique for cellular rhizobial cyclosophoraoses was developed based on fractional precipitation and partition chromatography. Cyclosophoraoses are known to function in the osmotic regulation and root nodule formation of legumes during the nitrogen fixation process. Cyclosophoraoses are produced as unbranched cyclic (1longrightarrow12)-${\beta}$-D-glucans in Agrobacterium or Rhizobium species. Recent research has shown that cyclosophoraoses can form inclusion complexation with various unstable or insoluble guest chemicals, thereby implying great potential for industrial application. Typical separation of pure cellular cyclosophoraoses has been so far carried out by several time-consuming steps, including size exclusion, anion exchange, and desalting liquid chromatographies, with a relatively poor recovery. However, the proposed method demonstrated that the successive application of fractional ethanol precipitation and one step of silica gel-based flash column chromatography was enough to simultaneously purify neutral or anionic forms of cyclosophoraoses. This novel technique is very rapid and provides a high recovery.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.81-90
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• 1992

Five buffaloes kept in normal ambient temperature ($30^{\circ}C$) showed no significant changes in the heart rate, respiratory rate, packed cell volume, plasma constituents and renal hemodymics during intravenous infusion of urea for 4 h. The rate of urine flow, fractional urea excretion, urinary potassium excretion and osmolar clearance significantly decreased while the renal urea reabsorption markedly increased during urea infusion. The decrease of fractional potassium excretion was concomitant with the reduction of the rate of urine flow and urine pH. In animals exposed to heat ($40^{\circ}C$) the rectal temperature heart rate and respiratory rate significantly increased while no significant changes in GFR and ERPF were observed. An intravenous infusion of urea in heat exposed animals caused the reduction of the rate of urine flow with no changes in renal urea reabsorption, urine pH and fractional electrolyte excretions. During heat exposure, there were marked increases in concentrations of total plasma protein and plasma creatinine whereas plasma inorganic phosphorus concentration significantly decreased. It is concluded that an increase in renal urea reabsorption during urea infusion in buffaloes kept in normal ambient temperature depends on the rate of urine flow which affect by an osmotic diuretic effect of electrolytes. The limitation of renal urea reabsorption in heat stressed animals would be attributed to an increases in either plasma pool size of nitrogenous substance or body metabolism.

• Molecules and Cells
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• 제22권2호
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• pp.203-209
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• 2006

TBP (TATA-binding protein)-related factor 2 (TRF2) regulates transcription during a nuber of cellular processes. We previously demonstrated that it is localized in the cytoplasm and is translocated to the nucleus by DNA-damaging agents. However, the cytoplasmic localization of TRF2 is controversial. In this study, we reconfirmed its cytoplasmic localization in various ways and examined its nuclear migration. Stresses such as heat shock, redox agents, heavy metals, and osmotic shock did not affect localization whereas genotoxins such as methyl methanesulfonate (MMS), cisplatin, etoposide, and hydroxyurea caused it to migrate to the nucleus. Adriamycin, mitomycin C and ${\gamma}$-rays had no obvious effect. We determined optimal conditions for the nuclear migration. The proportions of cells with nuclei enriched for TRF2 were 25-60% and 5-10% for stressed cells and control cells, respectively. Nuclear translocation was observed after 1 h, 4 h and 12 h for cisplatin, etoposide and MMS and hydroxyurea, respectively. The association of TRF2 with the chromatin and promoter region of the proliferating cell nuclear antigen (PCNA) gene, a putative target of TRF2, was increased by MMS treatment. Thus TRF2 may be involved in genotoxin-induced transcriptional regulation.

• 생명과학회지
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• 제18권11호
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• pp.1606-1611
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• 2008

Salmoenella를 포함한 그람 음성 세균의 외막 단백질들은 외부 환경 조건에 따라 그 발현에 변화가 생기는 경우가 많으며, 이렇게 발현된 외막 단백질들은 수송에 관여하는 통로, 외부 물질의 인지, 병원체의 부착인자 등 다양한 기능을 가진다. 본 연구에서는 이러한 외막 단백질 중 소수성 porin으로 알려진 OmpW 단백질에 주목하였다. ompW 유전자가 결손된 돌연변이주를 구축하여 CK10으로 명명하였으며, 야생주와 그 표현형적 특징을 비교한 결과 SDS에 대한 내성이 다소 증가함을 확인할 수 있었다. OmpW 특이적인 다클론성 항체를 조제하여 OmpW 단백질의 발현연구에 사용하였다. NaCl의 농도가 높아질수록 OmpW 단백질의 발현이 감소하였으며, OmpW의 발현이 최대인 조건은 NaCl이 배지에 첨가되지 않았을 경우이다. 따라서 OmpW는 Salmonella 균이 삼투환경에 대응하는데 관여할 것으로 예상되어 일차적으로 균의 생육을 조사한 결과, 다양한 삼투환경 하에서 Salmonella의 생육에는 OmpW 단백질의 결손이 큰 영향을 미치지는 않는 것을 확인하였다. 삼투환경 변화에 따른 OmpW 발현의 변화가 지니는 생물학적 의미는 앞으로 연구해야 할 숙제로 남는다.

• 한국식품영양학회지
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• 제28권3호
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• pp.404-414
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• 2015

Taurine is one of the most abundant free ${\beta}$-amino acids in the human body that accounts for 0.1% of the human body weight. It has a sulfonic acid group in place of the more common carboxylic acid group. Mollusks and meat are the major dietary source of taurine, and mother's milks also include high levels of this amino acid. The leukocytes, heart, muscle, retina, kidney, bone, and brain contain more taurine than other organs. Furthermore, taurine can be synthesized in the brain and liver from cysteine. There are no side effects of excessive taurine intake in humans; however, in case of taurine deficiency, retinal abnormalities, reduced plasma taurine concentration, and other abnormalities may occur. Taurine enters the cell via a cell membrane receptor. It is excreted in the urine (approximately 95%) and feces (approximately 5%). Taurine has a number of features and functions, including conjugation with bile acid, reduction of blood cholesterol and triglyceride levels, promotion of neuron cell differentiation and growth, antioxidant effects, maintenance of cell membrane stability, retinal development, energy generation, depressant effects, regulation of calcium level, muscle contraction and relaxation, bone formation, anti-inflammatory effects, anti-cancer and anti-atherogenic effects, and osmotic pressure control. However, the properties, functions, and effects of taurine require further studies in future.

• The Plant Pathology Journal
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• 제28권3호
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• pp.227-238
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• 2012

Mitogen-activated protein kinase (MAPK) cascades are conserved signaling modules in the eukaryotic cells. They are involved in many major cell processes in fungi such as stress responses, vegetative growth, pathogenicity, secondary metabolism and cell wall integrity. In this review, we summarized the advances of research on the MAPK signaling pathways in Alternaria species. As major phytopathogenic fungi, Alternaria species reduce crop production. In contrast to the five MAPK pathways known in yeast, only three MAPK pathways as Fus3/Kss1-type, Hog1-type, and Slt2-type have been characterized in Alternaria. The Fus3/Kss1-type MAPK pathway participates in regulation of vegetative growth, conidiation, production of some cell-wall-degrading enzymes and pathogenicity. The Hog1-type pathway is involved in osmotic and oxidative stress, fungicides susceptibility and pathogenicity. The Slt2-type MAP kinases play an important role on maintaining cell wall integrity, pathogenicity and conidiation. Although recent advances on the MAPK pathways in Alternaria spp. reveal many important features on the pathogenicity, there are many unsolved problems regarding to the unknown MAP kinase cascade components and network among other major signal transduction. Considering the economic loss induced by Alternaria spp., more researches on the MAPK pathways will need to control the Alternaria diseases.

• 한국잡초학회지
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• 제14권1호
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• pp.1-7
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• 1994

In vitro 조건에서 protoporphyrin IX(PPIX) 생합성에 미치는 제초제 S-23142와 acifluorfen의 영향을 알아보고자 시금치잎에서 엽록체내의 stroma와 membrane을 분리, 분획하고 형 광검출기가 장착된 역상HPLC를 이용하여 생합성된 PPIX 함량용 분석한 결과는 다음과 같다. 1. PPIX의 생합성이 이루어지는 부위는 엽록체 내의 stroma분획이었고 이는 모두 ALA(${\delta}$-aminolevulinic acid)에 의한 반응산물이었다. 2. PPIX의 생합성에 관련된 in vitro실험은 stroma분획을 이용하는 것이 가장 효율적이었다. 3. In vitro계에서 S-23142와 acifluorfen은 동일하게 PPIX의 생합성을 억제하였으며, 그 작용부위는 엽록체내의 stroma일 것으로 판단되었다.

• 환경영향평가
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• 제23권4호
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• pp.237-250
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• 2014

전 세계적으로 다양한 해양에너지 개발사업이 활발하게 추진되고 있으며 세계 각국은 해양에너지 개발에 대한 투자와 정책지원을 확대하고 있다. 삼면이 바다로 둘러싸인 우리나라는 풍부한 해양에너지 자원을 가지고 있으며 그 중에서도 해상풍력, 조류발전, 파력발전, 해수온도차 발전 등에 관심과 투자가 더욱 집중되고 있다. 하지만 친환경적이라 여겨지는 해양에너지 개발사업이 오히려 환경을 훼손하고 지역주민과의 갈등을 유발하는 대상으로 지적되기도 한다. 이러한 문제는 경제적 효율성만을 강조하여 입지를 선정하거나 발전시설의 건설과 운영이 미치는 해양생태계와 해양환경에 대한 영향조사가 소홀히 되거나 현실적으로 이에 대한 정보수집이 어렵다는데서 출발한다. 이에 본 연구는 국내외 사례분석을 통해 우리나라 해양에너지 개발사업이 보다 친환경적으로 추진될 수 있는 정책적, 제도적 방안은 무엇인지 모색하는데 목적을 두었다. 본 연구에서는 해양에너지 개발사업 계획 수립 시 전략환경영향평가를 실시하여 환경성을 고려한 선제적 입지선정을 진행할 것과 해양에너지 개발사업의 건설과 운영과정에서 지속적인 해양환경 모니터링을 실시하여 환경영향자료가 확대되는 방안이 강구 될 것 등을 제안하였다.