• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.819-827
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• 2006

The stress-strain relation of aluminum (Al) alloy foam cell wall was evaluated by the instrumented sharp indentation method. The indentation in a few micron ranges was performed on the cell wall of Al-alloy foam having a composition or Al-3wt.%Si-2wt.%Cu-2wt.%Mg as well as its precursor (material prior to foaming). To extract the stress-stram relation in terms of yield stress ${\sigma}_y$, strain hardening exponent n and elastic modulus E, the closed-form dimensionless relationships between load-indentation depth curve and elasto-plastic property were used. The tensile properties of precursor material of Al-alloy foam were also measured independently by uni-axial tensile test. In order to verify the validity of the extracted stress-strain relation, it was compared with the results of tensile test and finite element (FE) analysis. A modified cubic-spherical lattice model was proposed to analyze the compressive behavior of the Al-alloy foam. The material parameters extracted by the instrumented nanoindentation method allowed the model to predict the compressive behavior of the Al-alloy foam accurately.

• 한국미생물·생명공학회지
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• 제27권5호
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• pp.378-384
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• 1999

Protopectinase (PPases) are heterologous group of enzymes that degrade pectin from the insoluble protopection which is constituent of the middle lamella and primary cell wall of higher plants by restricted depolymerization. From the previous report[6], enzymatically separated plant cells, which are produced from plant tissues by PPases treatment, showed well-conserved cellular components with their rigid cell wall and this characteristic is applicable to preparation of novel food material. The purpose of this study is to investigate the effect of medium composition of PPase production from Bacillus subtilis EK11 which was selected as a PPase producer. Various carbon sources and concentrations on PPase production were studied and corn starch at 0.7% was the most effective for production of PPase. Among the nitrogen sources, yeast extract was the most effective for PPase production and the effect of (NH4)2SO4 was notable as inotganic nitrogen source. Inorganic compounds such as KH2PO4, K2HPO4, Na3-citrate.2H2O and MgSO4 were optimized for PPase production. PPase activity was inhibited by the adition of Ba2+ or Zn2+. The optimal medium for PPase production was devised: 0.7% corn starch, 0.3% yeast extract, 1.4% KH2PO4, 0.6% K2HPO4, 0.1% Na3-citrate.2H2O and 0.02% MgSO4. PPase production by using the optimum medium was carried out with shaking cultivation at 37$^{\circ}C$. The maximum PPase activity of 256unit/ml could be obtained after the cultivation for 48hrs. The activity was increased about 2.2timesthan the activity, 112 unit/ml, in basal medium.

• 펄프종이기술
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• 제47권4호
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• pp.144-150
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• 2015

Stems of Pinus thunbergii Parl. grown with high salinity were analyzed for chemical characteristics. Stem of 2 years was rich in soluble compounds and stem of 3 years reduced the amount of the soluble compound. But, the lignin content have not seen a large change. Also, Klason lignins of stem of 2 and 3 years has not changed in nitrogen and hydrogen content. In Klason process, it was significantly increased the carbon concentration due to the hydrolysis of the carbohydrate. In addition, the accumulation of xylan from Pinus thunbergii Parl. with salinity treatment were increased noticeably. Finally, functional group of Pinus thunbergii Parl. with salinity treatment were not changed.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.138-146
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• 2008

본 연구에서는 잎담배처리공정 및 궐련제조공정에서 분리되어 배출되는 바이오매스 중에서 가장 많은 양을 차지하는 황색종 주맥 바이오매스의 화학성분, 세포벽 물질 조성 및 비등온 조건에서의 열분해 특성에 대해 분석평가 하였다. 주맥 바이오매스에는 전건시료 기준으로 조회분이 19.1%, 전당성분은 20.7%로 다량 함유되어 있었고, 무기원소 중에는 칼륨이 3.8%, 개별당 중에는 fructose 함량이 6.2%로 가장 많은 것으로 분석되었다. 세포벽 성분 중 리그닌 함량은 3%로 낮았지만 펙틴의 함량은 7%로 높았으며, 홀로셀룰로오스는 전체의 13% 정도를 차지하였고, 이중 $\alpha$-셀룰로오스의 함량은 약 60%, 나머지는 $\beta$와 $\gamma$-셀룰로오스로 나타났다. 공기기체 조건과 질소기체 조건에서 황색종 주맥의 열분해 특성은 서로 다르게 나타났는데, 특히 산소가 존재하는 공기기체 조건에서는 $473^{\circ}C$와 $581^{\circ}C$ 온도에서 질소기체 조건에서는 나타나지 않는 열감량 피크들이 DTG 곡선에서 나타났으며, 이 중 $581^{\circ}C$ 온도에서의 피크는 열수추출하여 용해성분을 제거한 주맥의 열분해 시에는 발생하지 않았다. 분리된 용해성 성분을 냉동건조 시킨 후 열감량 분석을 실시한 결과 이 피크가 용해성 성분에서 기인된 것임을 확인할 수 있었다. 주맥 바이오매스의 헤미셀룰로오스와 셀룰로오스 열분해 특성차이는 질소기체 조건에서 더욱 확실하게 구별되어 나타나는 것을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제2권1호
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• pp.27-34
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• 1989

Different fractions of maize plant and whole mixed fodder were analysed for their chemical composition and dry matter digestibility (DMD). Highest crude protein (CP) values were found in leaves as compared to the other portions. Younger plants contained more CP as compared to the matured ones. The crude fiber (CF) content of various fractions of the plant ranged between 19.12 to 35.60% with maximum values in the bottom portion of the stem. Matured plants contained more CF. The analysis of cell wall constituents indicated that the maximum values for neutral detergent fiber (NDF) were found in the bottom portion and in the whole mixed plant. The highest levels of acid detergent fiber (ADF) were observed in bottom fraction followed by whole mixed plant, whereas the other plant fractions did not show any differences. Variation in acid detergent lignin (ADL) values existed in different fractions of the plant and the lowest were in the top portion of the stem. Although there existed a variation in the mineral composition of different fractions of the plants, the results were non significant. Maximum DMD was found in leaves followed by the whole mixed plant, middle and bottom portion of the stem. The values of DMD were higher in younger plants as compared to the matured ones. It may be concluded that younger plants and the upper portion of the plants have a higher nutritive value as compared to the matured plants and lower portion of the plants.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.62-70
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• 2020

Zygosaccharomyces rouxii is an important yeast that is required in the food fermentation process due to its high salt tolerance. In this study, the responses and resistance strategies of Z. rouxii against salt stress were investigated by performing physiological analysis at membrane level. The results showed that under salt stress, cell integrity was destroyed, and the cell wall was ruptured, which was accompanied by intracellular substance spillover. With an increase of salt concentrations, intracellular Na⁺ content increased slightly, whereas intracellular K⁺ content decreased significantly, which caused the increase of the intracellular Na⁺/K⁺ ratio. In addition, in response to salt stress, the activity of Na⁺/K⁺-ATPase increased from 0.54 to 2.14 μmol/mg protein, and the ergosterol content increased to 2.42-fold to maintain membrane stability. Analysis of cell membrane fluidity and fatty acid composition showed that cell membrane fluidity decreased and unsaturated fatty acid proportions increased, leading to a 101.21% rise in the unsaturated/saturated fatty acid ratio. The results presented in this study offer guidance in understanding the salt tolerance mechanism of Z. rouxii, and in developing new strategies to increase the industrial utilization of this species under salt stress.

• Journal of Ginseng Research
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• 제44권2호
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• pp.321-331
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• 2020

Background: The patatin-related phospholipase AIII family (pPLAIIIs) genes alter cell elongation and cell wall composition in Arabidopsis and rice plant, suggesting diverse commercial purposes of the economically important medicinal ginseng plant. Herein, we show the functional characterization of a ginseng pPLAIII gene for the first time and discuss its potential applications. Methods: pPLAIIIs were identified from ginseng expressed sequence tag clones and further confirmed by search against ginseng database and polymerase chain reaction. A clone showing the highest homology with pPLAIIIβ was shown to be overexpressed in Arabidopsis using Agrobacterium. Quantitative polymerase chain reaction was performed to analyze ginseng pPLAIIIβ expression. Phenotypes were observed using a low-vacuum scanning electron microscope. Lignin was stained using phloroglucinol and quantified using acetyl bromide. Results: The PgpPLAIIIβ transcripts were observed in all organs of 2-year-old ginseng. Overexpression of ginseng pPLAIIIβ (PgpPLAIIIβ-OE) in Arabidopsis resulted in small and stunted plants. It shortened the trichomes and decreased trichome number, indicating defects in cell polarity. Furthermore, OE lines exhibited enlarged seeds with less number per silique. The YUCCA9 gene was downregulated in the OE lines, which is reported to be associated with lignification. Accordingly, lignin was stained less in the OE lines, and the expression of two transcription factors related to lignin biosynthesis was also decreased significantly. Conclusion: Overexpression of pPLAIIIβ retarded cell elongation in all the tested organs except seeds, which were longer and thicker than those of the controls. Shorter root length is related to auxinresponsive genes, and its stunted phenotype showed decreased lignin content.

• 한국토양비료학회지
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• 제45권4호
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• pp.622-627
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• 2012

The processes to determine the composition, dynamics, and activity of infection mechanisms by the rhizosphere microflora have attracted the interest of scientists from multiple disciplines although considerable progress of the infection pathways and plant-pathogen interactions by soil borne fungal pathogens have been made. Soilborne pathogens are confined within a three-dimensional matrix of mineral soil particles, pores, organic matter in various stages of decomposition and a biological component. Among the physical and chemical properties of soils soil texture and matric water potential may be the two most important factors that determine spread exudates by soil borne fungal pathogens, based on the size of the soil pores. Pathogenic invasion of plant roots involves complex molecular mechanisms which occur in the diffuse interface between the root and the soil created by root exudates. The initial infection by soilborne pathogens can be caused by enzymes which breakdown cell wall layers to penetrate the plant cell wall for the fungus. However, the fate and mobility of the exudates are less well understood. Therefore, it needs to develop methods to control disease caused by enzymes produced by the soilborne pathogens by verifying many other possible pathways and mechanisms of infection processes occurring in soils.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.633-637
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• 2004

The experiment of silage for preservation of fresh Italian ryegrass (Lolium multiflorum) was carried out to examine whether the fermentation quality and microbial degradation in the rumen can be altered by the treatment of amino acids fermentation byproduct (AFB). The plant was ensiled for 40 days with 4 treatments of different ratios of AFB and sugarcane molasses (SCM) mixture. The treatment 2 (T2, AFB:SCM=100:0) and treatment 3 (T3, AFB:SCM=40:60) silages showed higher (p<0.05) concentrations of lactic acids, lower (p<0.05) pH and dry matter (DM) losses than the Control (T1, none additive) and treatment (T4, AFB:SCM=0:100) silages. The treatments 2 and 3 contained higher (p<0.05) DM and crude protein contents in silages compared to treatments 1 and 4 silages. The NDF, ADF and cellulose contents were also lower (p<0.05) in T2, T3 and T4 silages than T1 silage and fresh material before ensiled. The in situ rumen DM, NDF, ADF, hemicellulose and cellulose degradability was also higher (p<0.05) in T2, T3 and T4 silages than T1 silage, while the highest improvement was achieved with addition of AFB:SCM at level of 40:60 at ensiling. The result in this study indicates that the addition of AFB and SCM additives improved the silage fermentation and cell wall degradability of Italian ryegrass silage.

• 한국식품영양과학회지
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• 제15권2호
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• pp.171-175
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• 1986

고추과실의 연화와 관련한 pectin질의 변화를 조사할 목적으로 성숙단계별 조세포벽 시료로부터 분리한 pectin질을 화학적인 방법에 의하여 IAP와 CBP로 분획한 후 gel여과를 통한 개략적인 분자량변화를 살펴보았다. 고추과실이 연화되는 동안 세포벽 pectin을 구성하는 polyuronide는 IAP에서 보다 CBP에서 증가율이 높았는데 이것은 이와 결합한 hemicellulose의 분해에 기인하였고 이 hemicellulose분해물 중에서는 galactose가 가장 많았다. IAP의 개략적인 평균분자량은 성숙 연화하는 동안 60만에서 250만으로 고분자화하였고 CBP는 450만에서 20만으로 저분자화하였는데 CBP저분자화의 주된 원인은 이에 결합된 hemicellulose의 분해에 기인되는 것 같았다.