• 한국식품저장유통학회지
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• 제3권1호
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• pp.93-104
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• 1996

The cell wall components of fruit include cellulose. hemicellulose, pectin, glycoprotein etc., and the cell wall composition differs according to the kind of fruit. Fruit softening occurs as a result of a change in the cell wall polysaccharides : the middle lamella which links primary cell walls is composed of pectin. and primary cell walls are decomposed by a solution of middle lamella caused due to a result of pectin degradation by pectin degrading enzymes during ripening and softening, During fruit ripening and softening, contents of arabinose and galactose among non-cellulosic neutral sugars are notably decreased, and this occurs as a result of the degradation of pectin during fruit repening and softening since they are side-chained with pectin in the form of arabinogalactan and galactan Enzymes involved in the degradation of the cell wall include polygalacturonase, cellulose, pectinmethylesterase, glycosidase, etc., and various studies have been done on the change in enzyme activities during the ripening and softning of fruit. Among cell wall-degrading enzymes, polygalacturonase has the greatest effect on fruit softening, and its activity Increases during the maturating and softening of fruit. This softening leads to the textural change of fruit as a result of the degradation of cell wall polysaccharides by a cell wall degrading enzyme which exists in fruit.

• 한국식품영양과학회지
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• 제14권2호
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• pp.157-163
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• 1985

Various cell wall polysaccharides and related enzyme activities in hot pepper fruit were determined at different stages of maturity. The uronic acid content of cell walls decreased between immature green and turning stage fruit and then increased by red ripe stage. In contrast, cellulose content of cell walls changed only a little during ripening. Total neutal sugar content of cell wall material decreased 50% and galactose content of the walls decreased about 80% by the turning stage. Polygalacturonase and ${\beta}-galactosidase$ activities, as well as total hemicellulose from isolated cell walls of ripening hot pepper fruit were studied using gel filtration chromatography. Polygalacturonase activity was not detectable but 5 isozymes of ${\beta}-galactosidase$ were resolved. The activities of the enzymes were relatively high and gel filtration showed that they differed in molecular weight. Hemicellulose content decreased during ripening and softening. The molecular weight profiles shifted from high molecular weight to low molecular weight polymers during ripening. The changes in cell walls that may be associated with fruit softening involve the alteration of hemicellulose prior to the degradation of wall-bound uronic acid. It is suggested that the decrease in cell wall galactose involved changes in turnover of new cell wall components.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2007년도 춘계학술발표회
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• pp.65-73
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• 2007

The objective of this study is to understand how regulatory mechanisms respond to sugar status for more efficient carbon utilization and source-sink regulation in plants. So, we need to identify and characterize many components of sugar-response pathways for a better understanding of sugar responses. For this end, genes responding change of sugar status were screened using Arabidpsis cDNA arrays, and confirmed thirty-six genes to be regulated by sucrose supply in detached leaves by RNA blot analysis. Eleven of them encoding proteins for amino acid metabolism and carbohydrate metabolism were repressed by sugars. The remaining genes induced by sugar supply were for protein synthesis including ribosomal proteins and elongation factors. Among them, I focused on three hydrolase genes encoding putative $\beta$-galactosidase, $\beta$-xylosidase, and $\beta$-glucosidase that were transcriptionally induced in sugar starvation. Homology search indicated that these enzymes were involved in hydrolysis of cell wall polysaccharides. In addition to my results, recent transcriptome analysis suggested multiple genes for cell wall degradation were induced by sugar starvation. Thus, I hypothesized that enzyme for cell wall degradation were synthesized and secreted to hydrolyze cell wall polysaccharides producing carbon source under sugar-starved conditions. In fact, the enzymatic activities of these three enzymes increased in culture medium of Arabidopsis suspension cells under sugar starvation. The $\beta$-galactosidase encoded by At5g56870 was identified as a secretory protein in culture medium of suspension cells by mass spectrometry analysis. This protein was specifically detected under sugar-starved condition with a specific antibody. Induction of these genes was repressed in suspension cells grown with galactose, xylose and glucose as well as with sucrose. In planta, expression of the genes and protein accumulation were detected when photosynthesis was inhibited. Glycosyl hydrolase activity against galactan also increased during sugar starvation. Further, contents of cell wall polysaccharides especially pectin and hemicellulose were markedly decreased associating with sugar starvation in detached leaves. The amount of monosaccharide in pectin and hemicellulose in detached leaves decreased in response to sugar starvation. These results supported my idea that cell wall has one of function to supply carbon source in addition to determination of cell shape and physical support of plant bodies.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1157-1162
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• 2017

The goal of this study was to identify and characterize selected Trichoderma isolates by metabolic profiling and enzyme assay for evaluation of their potential as biocontrol agents against plant pathogens. Trichoderma isolates were obtained from the Rural Development Administration Genebank Information Center (Wanju, Republic of Korea). Eleven Trichoderma isolates were re-identified using ribosomal DNA internal transcribed spacer (ITS) regions. ITS sequence results showed new identification of Trichoderma isolates. In addition, metabolic profiling of the ethyl acetate extracts of the liquid cultures of five Trichoderma isolates that showed the best anti-Phytophthora activities was conducted using gas chromatography-mass spectrometry. Metabolic profiling revealed that Trichoderma isolates shared common metabolites with well-known antifungal activities. Enzyme assays indicated strong cell wall-degrading enzyme activities of Trichoderma isolates. Overall, our results indicated that the selected Trichoderma isolates have great potential for use as biocontrol agents against plant pathogens.

• Applied Biological Chemistry
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• 제35권6호
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• pp.507-512
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• 1992

대두(Glycine max)의 ${\beta}$-1,3-glucanase를 분리동정하고 benzyladenine(BA)이 이 효소의 세포내 함량과 활동도에 미치는 영향을 조사하였다. 또 세포벽의 callose함량과 protoplast의 세포벽재생에 미치는 BA의 영향을 조사하여, cytokinin이 식물의 세포벽재생을 촉진하는 기능이 있음을 확인하고 세포벽재생에 있어서 cytokinin의 작용기구를 검토하였다. 대두 ${\beta}-1,3-glucanase$는 21 kD의 polypeptide로 동정되었는데 이 polypeptide의 세포내함량과 효소활성은 BA처리에 의하여 저하되었다. 그리고 callus세포벽의 callose함량과 protoplast의 세포벽재생율이 BA처리에 의하여 증가되었다. 이 결과들은 cytokinin이 세포의 ${\beta}-1,3-glucanase$수준을 저하시켜 callose분해를 억제함으로써 세포벽 재생을 촉진할 수 있음을 보여주었다.

• Ocean and Polar Research
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• 제24권1호
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• pp.47-53
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• 2002

To evaluate the effect of reed population on the distribution and activities of microorganisms, vertical distribution of heterotrophic bacteria, degradation rate of cellulose, extracellular aminopeptidase activity (APA) and metabolic diversity based on GN2 Microlog plate were measured at two salt marsh stations in Hogok-ri, Namyang Bay, west coast of Korea. The number of heterotrophic bacteria at station 1 (reed population inhabited area) showed 2 to 6 times higher than that of station 2 (exposed area) with exception in the surface layer. Cellulose degradation rates in station 1 showed more than 50%. month-I and higher than that of station 2 (10.2 to 38.4%. $month^{-1}$). Yet the APA at two stations did not show difference except surface layer and suggested that APA might not be a significant factor in degrading marsh plant debris. Lipid class compounds, cell wall polymers and L-alanine were widely used by microorganisms. The number and activities of bacterial populations especially concerned in plant debris degradation seemed to be stimulated by the reed communities.

• Applied Biological Chemistry
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• 제43권3호
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• pp.169-173
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• 2000

저온에서 높은 세척력을 갖는 호소세제의 개발을 위하여 토양으로부터 alkaline protease의 활성이 높은 균주를 분리, 동정하였으며, 호소의 성질을 조사하였다. 분리균주의 형태적 특징은 Gram 음성균 이고, 간균$(0.6{\sim}0.7{\times}1.3{\sim}2.6\;{\mu}m\;in\;size)$ 형태를 하고 있으며, 운동성을 보였다. 또한 catalase 양성, aesculin, gelatin 및 casein 분해능이 있었다. 분리균주의 세포벽 구성 성분은 meso-DAP를 함유하였으며, G+C mol 함량은 43.3%를 나타내었다. 이러한 형태적, 생리 생화학적 특성의 결과로부터 분리 균주는 Acinetobacter 속으로 동정되었다. 분리 균주를 이용한 alkaline protease의 생산은 초기 pH 10과 $40^{\circ}C$에서 36시간 배양하였을 때 3,300 D.U/mL로 최대 효소 활성을 보였으며, 최적 pH와 온도는 9와 $60^{\circ}C$이었다. 또한 본 균주에 의해 생산된 alkaline protease는 두개의 활성 band를 나타내었다.

• 한국미생물·생명공학회지
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• 제26권4호
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• pp.352-357
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• 1998

방향족 화합물의 기본을 이루고 있는 benzoate와 m-toluate 혼합물 분해를 위한 45일간의 배양 결과 benzoate와 m-toluate 최적 기질 혼합비는 benzoate(75%): m-toluate(25%)일 때 가장 높은 균 생장율과 COD 제거율을 나타내었다. 또한 45일간의 배양 중 혼합기질의 농도가 2,000ppm으로 교체된 30일째의 benzoate와 m-toluate의 기질 분해율은 각각 94%와 79%였고 이때의 COD 제거율은 약 80%였다. 한편 효소 활성측정 결과 초기에 거의 검출되지 않았던 catechol 1,2-dioxygenase의 활성이 검출되어 m-toluate에 의해 본 균주의 효소 대사계가 유도 되었음을 알 수 있었다. 또한 배양 중 기질 농도에 대한 본 균주의 형태변화를 전자현미경으로 관찰한 결과, 기질의 농도가 높을수록 균 형태가 변화된 것으로 볼 때 일정 농도 이상의 방향족 화합물에 대한 내성은 대사에 관련된 효소 활성에 기인할 뿐만 아니라 아니라 세포벽 또는 세포막의 특성에 기인할 수도 있는 것으로 추측된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.153-156
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• 2000

1. A. ficuum의 genomic library 검색을 통해 Axe 유전자를 포함하고 있는 5.0 kb의 XbaI DNA 절편을 cloning 했다. Cloning 된 절편의 부분 염기서열 결정 결과 약 1.4 kb의 AXE coding 부위를 확인했으며, cDNA cloning과 그 염기서열의 결정을 통해 AXE coding 부위 내에는 두 개의 intron 이 존재함이 확인되었다. 2. AXE coding 부위의 아미노산 잔기 서열 검색 결과 A. awamori의 AXE와 약 92%의 상동성과 95%의 유사성이 있음이 확인 되었다. 3. 약 900 kb의 AXE의 cDNA를 yeast의 YEp352 vector의 GAL1 promoter의 전사 방향으로 cloning한 후 발현시킨 결과 형질전환체에서 acetyl esterase 활성을 확인했으며, 활성도는 숙주균주에 비해 약 4-5배의 높은 OD unit로 나타내는 것을 확인할 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.379-389
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• 2018

A nucleobase adenine is a fundamental component of nucleic acids and adenine nucleotides. Various biological roles of adenine have been discovered. It is not produced from degradation of adenine nucleotides in mammals but produced mainly during polyamine synthesis by dividing cells. Anti-inflammatory roles of adenine have been supported in IgE-mediated allergic reactions, immunological functions of lymphocytes and dextran sodium sulfate-induced colitis. However adenine effects on Toll-like receptor 4 (TLR4)-mediated inflammation by lipopolysaccharide (LPS), a cell wall component of Gram negative bacteria, is not examined. Here we investigated anti-inflammatory roles of adenine in LPS-stimulated immune cells, including a macrophage cell line RAW264.7 and bone marrow derived mast cells (BMMCs) and peritoneal cells in mice. In RAW264.7 cells stimulated with LPS, adenine inhibited production of pro-inflammatory cytokines $TNF-{\alpha}$ and IL-6 and inflammatory lipid mediators, prostaglandin $E_2$ and leukotriene $B_4$. Adenine impeded signaling pathways eliciting production of these inflammatory mediators. It suppressed $I{\kappa}B$ phosphorylation, nuclear translocation of nuclear factor ${\kappa}B$ ($NF-{\kappa}B$), phosphorylation of Akt and mitogen activated protein kinases (MAPKs) JNK and ERK. Although adenine raised cellular AMP which could activate AMP-dependent protein kinase (AMPK), the enzyme activity was not enhanced. In BMMCs, adenine inhibited the LPS-induced production of $TNF-{\alpha}$, IL-6 and IL-13 and also hindered phosphorylation of $NF-{\kappa}B$ and Akt. In peritoneal cavity, adenine suppressed the LPS-induced production of $TNF-{\alpha}$ and IL-6 by peritoneal cells in mice. These results show that adenine attenuates the LPS-induced inflammatory reactions.