• Journal of the Korean Wood Science and Technology
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• 제35권2호
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• pp.9-15
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• 2007

A comparative study of the structure and organization of the primary and secondary walls in different types of tropical plant waste fibers was carried out using transmission electron microscopy (TEM). The thickness of each layer was also measured using Image Analyzer. TEM micrographs haveconfirmed that cell wall structure of all six types of tropical plant waste fibers (empty fruit bunch, oil palm frond, oil palm trunk, coir, banana stem and pineapple leaf) has the same ultrastructure with wood fibre. The fibers consisted of middle lamella, primary and thick secondary wall with different thickness for different types of fibers. The secondary wall was differentiated into a $S_1$ layer, a unique multi-lamellae $S_2$ layer, and $S_3$ layer.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.207-210
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• 2007

We fabricated an optically compensated bend cell with pixel-isolating polymer wall. The polymer wall was formed by phase separation of LCs and UVcurable polymer. The fabricated cell had initially ${\pi}-twist$ state. It showed low driving voltage, wide viewing angle and fast response properties. Also, polymer wall provided the mechanical stability preventing distortion of a display image from pressure.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.81-81
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• 1998

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.333-337
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• 2000

An oil-degrading yeast, Yarrowia lipolytica 180, exhibits interesting cell surface characteristics under the growth on hydrocarbons. An electron microscopic study revealed that the cells grown on crude oil showed protrusions on the cell surface, and thicker periplasmic space and cell wall than the cell surface, and thicker periplasmic space and cell wall than the cells grown on glucose. Y. lipolytica cells lost its cell hydrophobicity after pronase(0.1 mg/ml) treatment. The strain produced two types of emulsifying materials during the growth on hydrocarbons; one was water-soluble extracellular materials and the other was cell wall-associated materials. Both emulsifying materials at lower concentration (0.12%) enhanced the oil-degrading activity of Moraxella sp. K12-7, which had medium emulsifying activity and negative cell hydrophobicity; however, it inhibited the oil-degrading activity of Pseudomunas sp. K12-5, which had medium emulsifying activity and cell hydrophobicity. These results suggest that the oil-degrading activity of Y. lipolytica 180 is closely associated with cell surface structure, and that a finely controlled application of Y.lipolytica 180 in combination with other oil-degrading microorganisms showed a possible enhancing efficiency of oil degradation.

• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.37-45
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• 2022

The fungal cell wall and membrane are the principal targets of antifungals. Herein, we report that myricetin exerts antifungal activity against Candida albicans by damaging the cell wall integrity and notably enhancing the membrane permeability. In the presence of sorbitol, an osmotic protectant, the minimum inhibitory concentration (MIC) of myricetin against C. albicans increased from 20 to 40 and 80 ㎍/ml in 24 and 72 h, respectively, demonstrating that myricetin disturbs the cell wall integrity of C. albicans. Fluorescence microscopic images showed the presence of propidium iodide-stained C. albicans cells, indicating the myricetin-induced initial damage of the cell membrane. The effects of myricetin on the membrane permeability of C. albicans cells were assessed using crystal violet-uptake and intracellular material-leakage assays. The percentage uptakes of crystal violet for myricetin-treated C. albicans cells at 1×, 2×, and 4× the MIC of myricetin were 36.5, 60.6, and 79.4%, respectively, while those for DMSO-treated C. albicans cells were 28.2, 28.9, and 29.7%, respectively. Additionally, myricetin-treated C. albicans cells showed notable DNA and protein leakage, compared with the DMSO-treated controls. Furthermore, treatment of C. albicans cells with 1× the MIC of myricetin showed a 17.2 and 28.0% reduction in the binding of the lipophilic probes diphenylhexatriene and Nile red, respectively, indicating that myricetin alters the lipid components or order in the C. albicans cell membrane, leading to increased membrane permeability. Therefore, these data will provide insights into the pharmacological worth of myricetin as a prospective antifungal for treating C. albicans infections.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1806-1816
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• 2019

Candida albicans is an opportunistic fungus possessing multiple virulence factors controlling pathogenicity. Cell wall proteins are the most important among these factors, being the first elements contacting the host. Ddr48 is a cell wall protein consisting of 212 amino acids. A DDR48 haploinsufficient mutant strain was previously found necessary for proper oxidative stress response and drug resistance. In this study, we aimed to further elucidate the role of Ddr48 by performing additional phenotypic characterization assays. A combinatory proteomic and bioinformatics approach was also undertaken to determine differentially expressed cell wall proteins. Results showed that the mutant strain exhibited a 10% decrease in adhesion mirrored by a 20% decrease in biofilm formation, and slight sensitivity to menadione, diamide, and SDS. Both strains showed similar hyphae formation, virulence, temperature tolerance, and calcofluor white and Congo red sensitivities. Furthermore, a total of 8 and 10 proteins were identified exclusively in the wild-type strain grown under filamentous and non-filamentous conditions respectively. Results included proteins responsible for superoxide stress resistance (Sod4 and Sod6), adhesion (Als3, Hyr4, Pmt1, and Utr2), biofilm formation (Hsp90, Ece1, Rim9, Ipp1, and Pra1) and cell wall integrity (Utr2 and Pga4). The lack of detection of these proteins in the mutant strain correlates with the observed phenotypes.

• 한국식품영양과학회지
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• 제34권10호
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• pp.1633-1637
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• 2005

Driselase, Cellulase, Macerozyme R-200, Macerozyme R-10및 Sumyzyme MC 등 5종의 시판 식물세포벽분해효소가 당근의 세포벽물질(CWM)로부터 제조한 알콜불용성 잔사(AIR)와 cellulose fraction의 f-hydroxybenzoic acid 추출에 미치는 영향을 조사하였다. 당근AIR의 주된 페놀화합물은 P-hydroxybenzoic acid로 1,977 $\mu$g/g AIR였으며, vanillin, ferulic acid, p-hydroxybenzaldehyde가 각각 55.9, 13.6, 10.6 $\mu$g/g AIR인 것으로 나타났다. 효소에 함유되어있는 ferulic acid의 함량은 Driselase, Cellulase, Macerozyme R-200, Macerozyme R-10, Sumyzyme MC에서 각각 2,319, 2,060, 391, 95.2, 34.1 $\mu$g/g인 것으로 나타났다. 이들 효소와 세포벽물질과의 반응을 조사한 결과, Driselase와 AIR의 반응 후 유리된 p-hydroxybenzoic acid의 함량은 56 $\mu$g/g AIR로 알칼리 (4 M NaOH) 추출한 총량의 2.8$\%$에 해당한다. 따라서 p-hydroxybenzoic acid는 AIR과 셀룰로오스 분획으로부터 이들 효소에 의해 분리되기 어려운 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.508-514
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• 2001

A stuructural gene (ycl) encoding novel yeast cell wall hydrolase, YCL, was cloned from alkalophilic Bacillus alcalophilus subsp. YB380 by PCR, and transformed into E. coli JM83. Based on the N-terminal and internal amino acid sequences of the enzyme, primers were designed for PCr. The positive clone that harbors 1.8 kb of the yeast cell wall hydrolase gene was selected by the colony hybridization method with a PCR fragment as a probe. According to the computer analysis, this gene contained a 400-base-paired N-terminal domain of the enzyme. Based on nucletide homology of the cloned gene, a 850 bp fragment was amplified and the C-terminal domain of the enzyme was sequenced. With a combination of the two sequences, a full nucleotide sequence for YCL was obtained. This gene, ycl, consisted of 1,297 nucleotides with 27 nucleotides with 27 amino acids of signal sequence, 83 redundant amino acids of prosequence, and 265 amino acids of the mature protein. This gene was then cloned into the pJH27 shuttle vector and transformed into the Bacillus subtilis DB104 to express the enzyme. It was confirmed that the expressed cell wall hydrolase that was produced by Bacillus subtilis DB104 was the same as that of the donor strain, by Western blot using polyclonal antibody (IgY) prepared from White Leghorn hen. Purified yeast cell wall hydrolase and expressed recombinant protein showed a single band at the same position in the Western blot analysis.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.661-666
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• 2006

The present study represents the investigation of in vitro immunopotentiating activities of cellular fractions of major lactic acid bacteria found in kimchi (KLAB) and bifidobacteria. The macrophage cells, RAW264.7, were stimulated with heat-killed whole-cell, cell-wall, and cytoplasmic fractions of four strains of KLAB (Leuconostoc mesenteroides, Leuconostoc citreum, Lactobacillus plantarum, and Lactobacillus sake) and two strains of bifidobacteria (Bifidobacterium longum and Bifidobacterium lactis) each, and then the production of nitric oxide (NO) and cytokines including tumor necrosis $factor-\alpha\;(TNF-\alpha)$ and interleukin-6 (IL-6) was measured by Griess and ELISA assays, respectively. Heat-killed wholecell and cell-wall fractions-but not the cytoplasmic fraction-from all strains of KLAB significantly increased the production of NO in RAW264.7 cells, and all fractions from bifidobacteria exerted similar effects. In the production of $TNF-\alpha$, heat-killed whole-cell and cell-wall fractions of L. plantarum showed the strongest effect, followed by L. sake and B. lactis, whereas other KLAB fractions did not exert any effect. In the production of IL-6, only whole-cell and cell-wall fractions of L. plantarum were effective. These results, taken together, indicate that L. plantarum might playa critical role in the immunopotentiating activities of kimchi.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2014년도 임시총회 및 하계학술연구발표회
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• pp.120-121
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• 2014

We investigate the field-dependence of energy barrier for various cell diameters and two type of geometry through the NEB method. We find that the energy barrier can depend strongly on the cell size when the switching is governed by the domain wall motion. Moreover we also examine the cell size dependence of energy barrier for two type of cell geometry. In the presentation, we will discuss the effect of domain wall formation and more various cell size on the energy barrier in detail.