• Title/Summary/Keyword: Intracellular pH

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Comparison of various cell lysis methods for Pichia pastoris

  • Han, Kyung-Ah;Kim, Sun-Yong;Rhee, Jong-Il
    • 한국생물공학회:학술대회논문집
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    • 2005.10a
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    • pp.889-893
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    • 2005
  • Cell lysis method is very important to study intracellular metabolites in microorganisms. In this study, various cell lysis methods were compared to find a good method analysing intracellular metabolites in P. pastoris. P. pastoris was cultivated in YPD medium at 30 $^{\circ}C$, 200 rpm for 24 hours and its morphology as well as the change in strain's shape were observed by microscopy. The UV/vis spectrophotometer was used to measure intracellular protein concentrations.

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Attenuation of ROS Generation by KCNE1 Genes in Cisplatin-treated Auditory Cells

  • Kim, Eun Sook;Park, Sang-Ho;Park, Raekil
    • Korean Journal of Clinical Laboratory Science
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    • v.45 no.3
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    • pp.114-119
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    • 2013
  • Potassium is essential for the proper functioning of the ears. The inner ear's endolymph differs from all other extracellular fluids (in its positive potential) and in the ionic compositions in the various parts of the endolymphatic space. Ion concentration of the endolymph is 150 mM of potassium, which is comparable to the concentrations in other organs. Cisplatin (cis-diamminedichloroplatinum II: CDDP) is one of the most effective anticancer drugs, widely used against various tumors. However, its clinical use is limited by the onset of severe side effects, including ototoxicity and nephrotoxicity. For ototoxicity, a number of evidences in cytotoxic mechanism of cisplatin, including perturbation of redox status, increase in lipid peroxydation, and formation of DNA adduct, have been suggested. Therefore, in this study, the author investigated the relationship between the potassium ions on cisplatin-induced cytotoxicity in HEI-OC1 cells associated with reactive oxygen species (ROS). KCNE1 gene expression by the concentration of intracellular potassium appeared in the plasma membrane and increased the concentration of intracellular potassium. Cisplatin decreased the viability of HEI-OC1 cells, but the KCNE1 gene increased. Also, the KCNE1 gene significantly suppressed generation of intracellular ROS by cisplatin. Western blot analysis showed that the KCNE1 gene increased phase II detoxification enzymes markers such as superoxide dismutase 1 (SOD1), superoxide dismutase (SOD2), NAD(P)H:quinine oxidoreductases (NQO1), which were associated with the scavenger of ROS. These results suggest that the KCNE1 gene for intracellular potassium concentration ultimately prevents ROS generation from cisplatin and further contributes to protect auditory sensory hair cells from ROS produced by cisplatin.

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The Third Intracellular Loop of truman ${\beta}_2$-adrenergic Receptor Expressed in E. coli Decreased Binding Affinity of Isoproterenol to ${\beta}_2$-adrenergic Receptor

  • Shin, Jin-Chul;Shin, Chan-Young;Lee, Mi-Ok;Lee, Sang-Bong;Ko, Kwang-Ho
    • Biomolecules & Therapeutics
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    • v.4 no.1
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    • pp.103-109
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    • 1996
  • To investigate the effect of the third intracellular loop (i3 loop) peptide of human $\beta$$_2$-adrenergic receptor on receptor agonist binding, we expressed third intracellular loop region of human $\beta$$_2$-adrenergic receptor as glutathione S-transferase fusion protein in E. coli. DNA fragment of the receptor gene which encodes amino acid 221-274 of human $\beta$$_2$-adrenergic receptor was amplified by polymerase chain reaction and subcloned into the bacterial fusion protein expression vector pGEX-CS and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was identified by SDS-PAGE and Western blot using monoclonal anti-GST antibody. The fusion protein expressed in this study was purified to an apparent homogeneity by glutathione Sepharose CL-4B affinity chromatography. The purified i3 loop fusion proteins at a concentration of 10 $\mu\textrm{g}$/ι caused right shift of the isoproterenol competition curve of [$^3$H]Dihydroalprenolol binding to hamster lung $\beta$$_2$-adrenergic receptor indicating lowered affinity of isoproterenol to $\beta$$_2$-adrenergic receptor possibly due to the uncoupling of receptor and G protein in the presence of the fusion protein. The uncoupling of receptor and G protein suggests that i3 loop region plays a critical role on $\beta$$_2$-adrenergic receptor G protein coupling.

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Controllable Biogenic Synthesis of Intracellular Silver/Silver Chloride Nanoparticles by Meyerozyma guilliermondii KX008616

  • Alamri, Saad A.M.;Hashem, Mohamed;Nafady, Nivien A.;Sayed, Mahmoud A.;Alshehri, Ali M.;El-Shaboury, Gamal A.
    • Journal of Microbiology and Biotechnology
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    • v.28 no.6
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    • pp.917-930
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    • 2018
  • Intracellular synthesis of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Meyerozyma guilliermondii KX008616 is reported under aerobic and anaerobic conditions for the first time. The biogenic synthesis of Ag-NP types has been proposed as an easy and cost-effective alternative for various biomedical applications. The interaction of nanoparticles with ethanol production was mentioned. The purified biogenic Ag/AgCl-nanoparticles were characterized by different spectroscopic and microscopic approaches. The purified nanoparticles exhibited a surface plasmon resonance band at 419 and 415 nm, confirming the formation of Ag/AgCl-NPs under aerobic and anaerobic conditions, respectively. The planes of the cubic crystalline phase of the Ag/AgCl-NPs were confirmed by X-ray diffraction. Fourier-transform infrared spectra showed the interactions between the yeast cell constituents and silver ions to form the biogenic Ag/AgCl-NPs. The intracellular Ag/AgCl-NPs synthesized under aerobic condition were homogenous and spherical in shape, with an approximate particle size of 2.5-30nm as denoted by the transmission electron microscopy (TEM). The reaction mixture was optimized by varying reaction parameters, including temperature and pH. Analysis of ultrathin sections of yeast cells by TEM indicated that the biogenic nanoparticles were formed as clusters, known as nanoaggregates, in the cytoplasm or in the inner and outer regions of the cell wall. The study recommends using the biomass of yeast that is used in industrial or fermentation purposes to produce Ag/AgCl-NPs as associated by-products to maximize benefit and to reduce the production cost.

Inhibitory effect of Fagopyrum esculentum on degranulation and production of cytokine in RBL-2H3 cells (교맥의 RBL-2H3 비만세포 탈과립과 cytokine 생산 억제 효과)

  • Kang, Kyung-Hwa;Lee, Seung-Yeon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.25 no.3
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    • pp.1-12
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    • 2012
  • Objectives : Fagopyrum esculentum(FE) has been used for removal of inflammation of internal organs and treatment of sore and ulcer by heat toxin in Korean herbal medicines. In this study, To investigated the protective effect of FE on allergic response, we determined whether FE inhibits allergic response. Methods : The effect of FE was analyzed by ELISA, RT-PCR and Western blot in RBL-2H3 cells. We investigated cell viability, ${\beta}$-hexosaminidase, as a marker of degranulation, cytokne, and intracellular ROS and MAPK and NF-${\kappa}B$ signaling. Results : We found that FE suppressed ${\beta}$-hexosaminidase release, the production of IL-4 and TNF-${\alpha}$ and intracellular ROS level in RBL-2H3 by the anti-DNP IgE plus DNP-HSA stimulation. FE also significantly inhibited cytokine mRNA expressions, such as IL-$1{\beta}$, IL-2, IL-3, IL-4, IL-5, IL-6, IL-13, TNF-${\alpha}$ and GM-CSF in RBL-2H3. In addition, PF suppressed the phospholyation of ERK1/2, JNK1/2, p38 and $I{\kappa}B{\alpha}$ and NF-${\kappa}B$ signal transduction pathway. Conclusions : Our results indicate that FE protects against allergic response and exerts an anti-inflammatory effect through the inhibition of degranulation and production of cytokines and ROS via the suppression MAPK and NF-${\kappa}B$ of signal transduction. Abbrevations : FE, Fagopyrum esculentum; RBL-2H3, rat basophilic leukemia cell line; ROS, reactive oxygen species; MAPK, Mitogen-activated protein kinase; $NF{\kappa}B$, nuclear factor ${\kappa}B$; $TNF{\alpha}$, Tumor necrosis factor alpha; GM-CSF, Granulocyte macrophage colony-stimulating factor; ERK, extracellular-signal-regulated kinase; JNK, c-Jun NH2-terminal kinase; p38, p38 MAP kinase; $I{\kappa}B{\alpha}$, inhibitory-kappa B alpha.

Purification and Characterization of an Alkali-Thermostable Lipase from Thermophilic Anoxybacillus flavithermus HBB 134

  • Bakir, Zehra Burcu;Metin, Kubilay
    • Journal of Microbiology and Biotechnology
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    • v.26 no.6
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    • pp.1087-1097
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    • 2016
  • An intracellular lipase from Anoxybacillus flavithermus HBB 134 was purified to 7.4-fold. The molecular mass of the enzyme was found to be about 64 kDa. The maximum activity of the enzyme was at pH 9.0 and 50℃. The enzyme was stable between pH 6.0 and 11.0 at 25℃, 40℃, and 50℃ for 24 h. The Km and Vmax of the enzyme for pNPL substrate were determined as 0.084 mM and 500 U/mg, respectively. Glycerol, sorbitol, and mannitol enhanced the enzyme thermostability. The enzyme was found to be highly stable against acetone, ethyl acetate, and diethyl ether. The presence of PMSF, NBS, DTT and β-mercaptoethanol inhibited the enzyme activity. Hg2+, Fe3+, Pb2+, Al3+, and Zn2+ strongly inhibited the enzyme whereas Li+, Na+, K+, and NH4+ slightly activated it. At least 60% of the enzyme activity and stability were retained against sodium deoxycholate, sodium taurocholate, n-octyl-β-D-glucopyranoside, and CHAPS. The presence of 1% Triton X-100 caused about 34% increase in the enzyme activity. The enzyme is thought to be a true lipase since it has preferred the long-chain triacylglycerols. The lipase of HBB 134 cleaved triolein at the 1- or 3-position.

Intracellular Flux Prediction of Recombinant Escherichia coli Producing Gamma-Aminobutyric Acid

  • Sung Han Bae;Myung Sub Sim;Ki Jun Jeong;Dan He;Inchan Kwon;Tae Wan Kim;Hyun Uk Kim;Jong-il Choi
    • Journal of Microbiology and Biotechnology
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    • v.34 no.4
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    • pp.978-984
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    • 2024
  • Genome-scale metabolic model (GEM) can be used to simulate cellular metabolic phenotypes under various environmental or genetic conditions. This study utilized the GEM to observe the internal metabolic fluxes of recombinant Escherichia coli producing gamma-aminobutyric acid (GABA). Recombinant E. coli was cultivated in a fermenter under three conditions: pH 7, pH 5, and additional succinic acids. External fluxes were calculated from cultivation results, and internal fluxes were calculated through flux optimization. Based on the internal flux analysis, glycolysis and pentose phosphate pathways were repressed under cultivation at pH 5, even though glutamate dehydrogenase increased GABA production. Notably, this repression was halted by adding succinic acid. Furthermore, proper sucA repression is a promising target for developing strains more capable of producing GABA.

Propofol Post-conditioning Protects against COS-7 Cells in Hypoxia/reoxygenation Injury by Induction of Intracellular Autophagy

  • Kwak, Jin-Won;Kim, Eok-Nyun;Park, Bong-Soo;Kim, Yong-Ho;Kim, Yong-Deok;Yoon, Ji-Uk;Kim, Cheul-Hong;Yoon, Ji-Young
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.14 no.1
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    • pp.49-56
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    • 2014
  • Background: Propofol (2.6-diisopropylphenol) is a widely used intravenous anesthetic agent for the induction and maintenance of anesthesia during surgeries and sedation for ICU patients. Propofol has a structural similarity to the endogenous antioxidant vitamin E and exhibits antioxidant activities.13) However, the mechanism of propofol on hypoxia/reoxygenation (H/R) injury has yet to be fully elucidated. We investigated how P-PostC influences the autophagy and cell death, a cellular damage occurring during the H/R injury. Methods: The groups were randomly divided into the following groups: Control: cells were incubated in normoxia (5% CO2, 21% O2, and 74% N2) without propofol treatment. H/R: cells were exposed to 24 h of hypoxia (5% CO2, 1% O2, and 94% N2) followed by 12 h of reoxygenation (5% CO2, 21% O2, and 74% N2). H/R + P-PostC: cells post-treated with propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation. 3-MA + P-PostC: cells pretreated with 3-MA and post-treated propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation Results: The results of our present study provides a new direction of research on mechanisms of propofol-mediated cytoprotection. There are three principal findings of these studies. First, the application of P-PostC at the onset of reoxygenation after hypoxia significantly increased COS-7 cell viability. Second, the cellular protective effect of P-PostC in H/R induced COS-7 cells was probably related to activation of intra-cellular autophagy. And third, the autophagy pathway inhibitor 3-MA blocked the protective effect of P-PostC on cell viability, suggesting a key role of autophagy in cellular protective effect of P-PostC. Conclusions: These data provided evidence that P-PostC reduced cell death in H/R model of COS-7 cells, which was in agreement with the protection by P-PostC demonstrated in isolated COS-7 cells exposed to H/R injury. Although the this study could not represent the protection by P-PostC in vivo, the data demonstrate another model in which endogenous mechanisms evoked by P-PostC protected the COS-7 cells exposed to H/R injury from cell death.

Antioxidant Effect of Edaravone on the Development of Preimplantation Porcine Embryos against Hydrogen Peroxide-Induced Oxidative Stress

  • Do, Geon-Yeop;Kim, Jin-Woo;Chae, Sung-Kyu;Ahn, Jae-Hyun;Park, Hyo-Jin;Park, Jae-Young;Yang, Seul-Gi;Koo, Deog-Bon
    • Journal of Embryo Transfer
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    • v.30 no.4
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    • pp.289-298
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    • 2015
  • Edaravone (Eda) is a potent scavenger of inhibiting free radicals including hydroxyl radicals ($H_2O_2$). Reactive oxygen species (ROS) such as $H_2O_2$ can alter most kinds of cellular molecules such as lipids, proteins and nucleic acids, cellular apoptosis. In addition, oxidative stress from over-production of ROS is involved in the defective embryo development of porcine. Previous study reported that Eda has protective effects against oxidative stress-like cellular damage. However, the effect of Eda on the preimplantation porcine embryos development under oxidative stress is unclear. Therefore, in this study, the effects of Eda on blastocyst development, expression levels of ROS, and apoptotic index were first investigated in preimplantation porcine embryos. After in vitro fertilization, porcine embryos were cultured for 6 days in PZM medium with Eda ($10{\mu}M$), $H_2O_2$ ($200{\mu}M$), and Eda+$H_2O_2$ treated group, respectively. Rate of blastocyst development was significantly increased (P<0.05) in the Eda treated group compared with only $H_2O_2$ treated group. And, we measured intracellular levels of ROS by DCF-DA staining methods and investigated numbers of apoptotic nuclei by TUNEL assay analysis is in porcine blastocyst, respectively. Both intracellular ROS levels and the numbers of apoptotic nucleic were significantly decreased (P<0.05) in porcine blastocysts cultured with Eda ($10{\mu}M$). More over, the total cell number of blastocysts were significantly increased (P<0.05) in the Eda-treated group compared with untreated group and the only $H_2O_2$ treated group. Based on the results, Eda was related to regulate as antioxidant-like function according to the reducing ROS levels during preimplantation periods. Also, Eda is beneficial for developmental competence and preimplantation quality of porcine embryos. Therefore, we concluded that Eda has protective effect to ROS derived apoptotic stress in preimplantation porcine embryos.