• Title/Summary/Keyword: transduction

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Optical Biosensors

  • Gang, Sin-Won
    • 한국생물공학회:학술대회논문집
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    • 2000.11a
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    • pp.105-110
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    • 2000
  • Biosensors consist principally of two basic components, receptor and transducer. The transducer part of the sensor serves the signal transfer from the output domain of the recognition system. Optical method of transducer have many benefits, based on phenomena like emission and absorption. This paper will review the methode of optical transduction in brief and out some new development.

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THE PHOTO-MECHANICAL RESPONSES IN THE UNICELLULAR CILIATES

  • Song, Pill-Soon
    • Journal of Photoscience
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    • v.2 no.1
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    • pp.31-35
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    • 1995
  • Light signals in the form of intensity gradient, propagation direction, and wavelength elicit diverse mechanical responses ("photomechanical responese") in most organisms. The single cell ciliates, Stentor coeruleus and Blepharisma japonicum, are particularly sensitive to the light of visible wavelengths. In this paper, the way in which the seemingly sophisticated light signal transduction is triggered by the photosensory apparatus will be described in terms of the photoreceptor structure and photochemical function.

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Induction of the Nuclear Proto-Oncogene c-fos by the Phorbol Ester TPA and c-H-Ras

  • Kazi, Julhash U.;Soh, Jae-Won
    • Molecules and Cells
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    • v.26 no.5
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    • pp.462-467
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    • 2008
  • TPA is known to cooperate with an activated Ras oncogene in the transformation of rodent fibroblasts, but the biochemical mechanisms responsible for this effect have not been established. In the present study we used c-fos promoter-luciferase constructs as reporters, in transient transfection assays, in NIH3T3 cells to assess the mechanism of this cooperation. We found a marked synergistic interaction between TPA and a transfected v-Ha-ras oncogene in the activation of c-fos promoter and SRE. SRE has binding sites for TCF and SRF. A dominant-negative Ras (ras-N17) inhibited the TPA-Ras synergy by blocking the PKC-MAPK-TCF pathway. Dominant-negative RhoA and Rac1 (but not Cdc42Hs) inhibited the TPA-Ras synergy by blocking the Ras-Rho-SRF signaling pathway. Constitutively active $PKC{\alpha}$ and $PKC{\varepsilon}$ showed synergy with v-Ras. These results suggest that the activation of two distinct pathways such as Ras-Raf-ERK-TCF pathway and Rho-SRF pathway are responsible for the induction of c-fos by TPA and Ras in mitogenic signaling pathways.

The Heat Shock Protein 27 (Hsp27) Operates Predominantly by Blocking the Mitochondrial-Independent/Extrinsic Pathway of Cellular Apoptosis

  • Tan, Cheau Yih;Ban, Hongseok;Kim, Young-Hee;Lee, Sang-Kyung
    • Molecules and Cells
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    • v.27 no.5
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    • pp.533-538
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    • 2009
  • Heat shock protein 27 (Hsp27) is a molecular chaperone protein which regulates cell apoptosis by interacting directly with the caspase activation components in the apoptotic pathways. With the assistance of the Tat protein transduction domain we directly delivered the Hsp27 into the myocardial cell line, H9c2 and demonstrate that this protein can reverse hypoxia-induced apoptosis of cells. In order to characterize the contribution of Hsp27 in blocking the two major apoptotic pathways operational within cells, we exposed H9c2 cells to staurosporine and cobalt chloride, agents that induce mitochondria-dependent (intrinsic) and -independent (extrinsic) pathways of apoptosis in cells respectively. The Tat-Hsp27 fusion protein showed a greater propensity to inhibit the effect induced by the cobalt chloride treatment. These data suggest that the Hsp27 predominantly exerts its protective effect by interfering with the components of the extrinsic pathway of apoptosis.

Artificial Activation of Pig Oocytes Arrested at meiotic Metaphase II (제2감수분열 중기에서 발달정지된 돼지 난자의 인위적 난활성)

  • R. S. Prather;;Z. Mach ty
    • Korean Journal of Animal Reproduction
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    • v.20 no.4
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    • pp.395-412
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    • 1997
  • Mammalian eggs are ovulated arrested at meiotic metaphase II until fertilization. Generally in mammals, fertilization results in a series of intracellular calcium oscillations that are mediated by inositol triphosphate (IP$^3$) or cyclic adenosine diphosphoribose (cADPr). The high levels of maturation promotion factor (MPF) within the cell decrease, pronuclei form, the cytoskeleton is reorganized and proteins are post-translationally modified. If all is normal, the newly formed embryo initiates the developmental program specific to that species. Artificial methods of producing these effects in pig oocytes are discussed. One potential mechanism mediated via a signal transduction pathway is present in pig oocytes. Stimulation of this pathway leads to the early events following fertilization, and electrical stimulation leads to apparently normal de v velopment to day 12. Further studies are needed to determine which mechanism(s) the sperm uses to initiate development.

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DNA Microarray Analysis of Immediate Response to EGF Treatment in Rat Schwannoma Cells

  • OH, Min-Kyu;Scoles, Daniel R.;Pulst, Stefan-M.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.10 no.5
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    • pp.444-450
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    • 2005
  • Epidermal growth factor (EGF) activates many intracellular effector molecules, which subsequently influence the expression levels of many genes involved in cell growth, apoptosis and signal transduction, etc. In this study, the early response of gene expressions due to EGF treatment was monitored using oligonucleotide DNA microarrays in rat schwannoma cell lines. An immunoblotting experiment showed the successful activation of EGF receptors and an effector protein, STAT5, due to EGF treatment. The microarray study showed that 35 genes were significantly induced and 2 were repressed within 60 min after the treatment. The list of induced genes included early growth response 1, suppressor of cytokine signaling 3, c-fos, interferon regulatory factor 1 and early growth response 2, etc. According to the microarray data, six of these were induced by more than 10-fold, and showed at least two different induction patterns, indicating complicated regulatory mechanisms in the EGF signal transduction.