• Title/Summary/Keyword: endoplasmic reticulum

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An Electron Microscopic Observation of Some Membrane Structures of Lens Fibers of Regenerating Lens in Triturus pyrrhogaster (Triturus pyrrhogaster 에서 再生되는 水晶體纖維 細胞中 膜構造에 관한 電子顯微鏡的 觀察)

  • Sung, Hwan-Soon;Sung, Hwan-Sang
    • The Korean Journal of Zoology
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    • v.11 no.1
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    • pp.5-12
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    • 1968
  • The membrane structures were electron microscopically studied in the elongating lens fibers of the regenerating lens of adult Triturus pyrrhogaster. Observations were focused on the endoplasmic reticulum and mitochondria. The endoplasmic reticulum developed in the vicinity of the nucleus with active blebbing of the outer membrane. At the same time, the concentration of mitochondria around the rough-surfaced endoplasmic reticulum near by the nucleus was always observed. Both endoplasmic reticulum and mitochondrion undergo disintegration in the apical portion apart from the nucleus. Some considerations were discussed with reference to published data.

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Radioprotective Effect of Methylene Blue: 2. Electron Microscopy of the Effect of Methylene Blue on the Liver and Heart of Rats following Gamma-Irradiation (Methylene Blue의 방사선방어결과 2. Methylene Blue가 $\gamma$선에 조사한 흰줘의 간 및 심장조직에 미치는 전자현미경적 연구)

  • Sang Yul Nam;Seung Han Chang
    • The Korean Journal of Zoology
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    • v.12 no.4
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    • pp.114-122
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    • 1969
  • Electron microscopic examination of the liver and heart tissues of methylene blue-treated rats before gamma-irradiation was observed in this study. 1. It was observed severe alteration and degeneration of organelles: accumulation of glycogen particles, severe swollen mitochondria, and broken endoplasmic reticulum in liver tissue of saline-treated rat(control) opposed by emthylene blue-treated rat at 64 and 212 hours following gamma-irradiation. 2. Heart muscles of both methylene blue-treated and saline-treated rats showed no significant alterations, but it was observed that slightly elongated mitochondria with broken cristae and some of vacuoles as well as increased glycogen particles in sarcoplasmic reticulum at 212 hours following gamma-irradiation. 3. It may be considered that methylene blue greatly reduces the sensitivities of rats to gamma-irradiation.

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Inhibitory Effects of Litsea japonica Flesh Water Extract against Endoplasmic Reticulum Stress in HepG2 Cells (HepG2 세포에서 까마귀쪽나무 과육 열수 추출물의 소포체 스트레스 억제 효능)

  • Kim, Eun Ok;Jegal, Kyung Hwan;Kim, Jae Kwang;Lee, Ju Sang;Park, Chung A;Kim, Sang Chan;Cho, Il Je
    • Herbal Formula Science
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    • v.26 no.4
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    • pp.307-318
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    • 2018
  • Objectives : Endoplasmic reticulum (ER) stress designates cellular responses to the accumulation of misfolded and unfolded proteins in ER, which is related to a variety of liver diseases. Present study investigated the inhibitory effects of Litsea japonica flesh water extract (LJE) aganist ER stress. Methods : After HepG2 cells were pretreated with LJE and subsequently exposed to tunicamycin (Tm) or thapsigargin (Tg), expression of C/EBP homologous protein (CHOP), glucose regulated protein 78 kDa (GRP78), asparagine synthetase (ASNS), and endoplasmic reticulum DnaJ homologue 4 (ERDJ4) were determined by immunoblot and real-time PCR analysis. Three canonical signaling pathways in response to ER stress were examined to explore molecular mechanisms involved. Results : Pretreatment of 1 mg/mL LJE inhibited Tm- or Tg-induced CHOP expression, while L. japonica fruit water extract did not. In addition, LJE decreased the levels of GRP78, ASNS, and ERDJ4 mRNA by Tm. Moreover, phosphorylations of eukaryotic translation initiation factor $2{\alpha}$ and inositol-requiring enzyme 1, expression of nuclear form of activating transcription factor $6{\alpha}$, and transactivation of ER stress response element- and unfolded protein response element-harboring luciferase activities were inhibited by LJE pretreatment. Conclusions : Present results suggest that LJE would be a candidate to prevent or treat ER stress-mediated liver injuries.

Subcellular Localization of Capsaicin-Hydrolyzing Enzyme in Rat Hepatocytes (Capsaicin 가수분해효소의 흰쥐 간세포내 소재확인)

  • Park, Young-Ho;Lee, Sang-Sup
    • YAKHAK HOEJI
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    • v.38 no.1
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    • pp.12-19
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    • 1994
  • Capsaicin(8-methyl-N-vanillyl-6-nonenamide) is the principal pungent component of Capsicum fruits. This work is directed to the capsaicin-hydrolyzing enzyme playing a key role in the rate limiting and critical step of capsaicin metabolism. In order to get precise information on the enzyme's subcellular location, rat liver homogenate was divided into six subcellular fractions by differential centrifugation technique: crude nuclear pellet, PNS(post nuclear supernatant) fraction, lysosomal pellet, cytosol, Tris wash fraction, micrisomes. Capsaicin-hydrolysing enzyme activity was analysed by high performance liquid chromatography(HPLC). This enzyme was found at the highest specific activity in the microsomal fraction and co-distributed with marker enzymes of the endoplasmic reticulum, NADPH-cytochrome c reductase and nucleoside diphosphatase. This is compatible with the result of ninhydrin color reaction of vanillylamine, primary metabolite of capsaicin hydrolysis, on thin layer chromatography(TLC). This enzyme is most active at pH $8.0{\sim}9.0$. Definite subcellular location of this enzyme will make it easy to proceed with further study.

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Endoplasmic Reticulum Stress Response of Bombyx mori Calreticulin

  • Goo, Tae-Won;Park, Soojung;Jin, Byung-Rae;Yun, Eun-Young;Kim, Iksoo;Nho, Si-Kab;Kang, Seok-Woo;Kwon, O-Yu
    • Proceedings of the Korean Society of Sericultural Science Conference
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    • 2003.10a
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    • pp.78-79
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    • 2003
  • To further understanding of the role of calreticulin in insects, we have isolated a cDNA of calreticulin from silkworm, Bombyx mori. The cDNA encodes a 398 amino acid residues of B. mori calreticulin with endoplasmic reticulum retentional HDEL motif at its C-terminus, and a predicted molecular mass of 45801 Da. The B. mori calreticulin shows high protein homology with those of G mellonella (88%), A. aegypti (71%) and H. sapiens (63%). (omitted)

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Insulin-like Growth Factor-1 (IGF-1) Gene Expression Is Enhanced under Hypothermia but Depressed under Additional Ischemic Stimulus

  • Kwon, O-Yu;Kwon, Kisang;Yu, Kweon;Kim, Seung-Whan
    • Biomedical Science Letters
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    • v.21 no.2
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    • pp.126-130
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    • 2015
  • There are several studies that show hypothermia improves cellular ischemia damages on experimental and clinical bases. However, its exact molecular mechanisms are unclear. In this study, we demonstrate that hypothermia induced insulin-like growth factor 1 (IGF1) gene expression, and its expression was dramatically decreased under ischemic insults. It was also demonstrated that hypothermia activated endoplasmic reticulum (ER) stress sensors especially both the phosphorylation of $eIF2{\alpha}$ (eukaryotic translation initiation factor 2 alpha) and ATF6 (activating transcription factor-6) proteolytic cleavage. However, the factors of apoptosis and autophagy were not associated with hypothermia. We suggest that hypothermia-treated IGF1 gene expression after ischemia may show a good possibility for the development of treatments and diagnostic methods in cerebral ischemic damages.