• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.207-210
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• 2000

Pseudomonas oleovorans was cultivated to produce medium chain length polyhydroxyalkanoates (MCL-PHA) fram octanoic acid and ammonium nitrate as carbon and nitrogen source, respectively, by a pH-stat fed-batch culture technique. The octanoate concentration of the culture broth was maintained below 4 g/L by feeding the mixture of octanoic acid and ammonium nitrate when the culture pH rose above high limit. The effect of the ratio of octanoic acid to ammonium nitrate (C/N ratio) in the feed on the PHA production was examined. The final cell concentrations of 62.5, 54.7, and 9.5 g/L, PHA contents of 62.9, 75.1, and 67.6% of dry cell weight, and productivities of 1.03, 0.632, and 0.161 g/L/h were obtained when the C/N ratio in the feed were 10, 20, and 100 g octanoic acid/g ammonium nitrate, respectively.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.321-324
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• 2001

Two recombinant Escherichia coli strains, GCSC6576 harboring a plasmid pSYL107 containing the Ralstonia eutropha polyhyclroxyalkanoate (PHA) biosynthesis genes and a fadR atoC mutant LS5218 harboring a plasmid pJC4 containing the Alcaligenes latus PHA biosynthesis genes were compared for their ability to synthesize poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] from whey as the sale carbon source. With the pH-stat fed-batch culture of E. coli LS5218, 、 ,ve obtained a cell concentration, a P(3HB-co-3HV) concentration. a P(3HB-co-3HV) content, and a 3HV fraction of 31.8 g/L, 10.6 g/L, 33.4 wt%. and 6.26 mol%, respectively at 39 h.

• The Korea Journal of Herbology
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• v.35 no.4
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• pp.9-16
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• 2020

Objective : To identify the effects of the water extract of Liriope platyphylla tuber (Liriopis tuber, LT) on the activation of astocytes, we investigated the regulatory effects of LT extract on H₂O₂-induced oxidative damage in C6 rat astrocytes. Methods : LT extract was extracted with boiling water. C6 cell line were treated with LT extract at 1, 2, and 3 mg/㎖ or without for 30 min and then stimulated with H₂O₂ at 5 ㎛ for 24 hr. The cell viability was measured by MTT assay. The expression of glial fibrillary acidic protein (GFAP), signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (pSTAT3), cyclooxygenase (COX-2), Nuclear factor-κB (NF-κB), superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1), catalase, Akt, phospho-Akt (p-Akt) phosphoinositide 3-kinases (PI3K), and protein kinase C alpha (PKCα) proteins were determined by Western blot, respectively. GFAP expression was also observed with immunocytochemistry under a fluorescence microscope. Results : LT extract induced cell proliferation in H₂O₂-stimulated C6 cells. LT extract significantly inhibited the expression of GFAP, NF-κB and COX-2 and increased the expression of HO-1 and the phosphorylation of STAT3 in H₂O₂-stimulated C6 cells. LT extract also significantly increased the phosphorylation of Akt and decreased the expression of PKCα in a dose-dependent manner in H₂O₂-stimulated C6 cells. Conclusions : LT extract can regulate H₂O₂-induced activation of astrocytes through inhibiting the expression of NF-κB, COX-2 and regulating Akt / HO-1, STAT3 or PKCα signaling pathway.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.234-239
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• 2015

Various leaching tests were applied to the soil affected by accidental leakage of HF in an industrial area in Korea. Three different leaching methods including pH-stat, continuous batch leaching, and column tests were adopted to assess leaching characteristics and mobility of fluorine(F) in soil and the potential risks to ecosystem. Both natural and spiked samples were used for the leaching tests. F concentrations in the batch tests increased by leaching rapidly in the early stage of leaching and then maintained rather constant levels. Column leaching test also show similar result to that of the batch test. pH also controlled the leaching behavior of the soil. With increasing pH, more F was released in the pH-stat test. This is mainly due to the competition and exchange with hydroxyl ions, as pH increase to the alkaline range. Most of the F released by the accident seem to have removed in the very early stage of leaching, whereas some natural proportion from soil minerals are thought to have been released very slowly. Therefore, little F released during the accident remained, based on the results of this study on the samples after two years of the accident. We could conclude that soil contaminated by external effects such as chemical accidents should be managed immediately, especially with F.

• Journal of Acupuncture Research
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• v.34 no.1
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• pp.23-30
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• 2017

Objectives : In this study, the roles of Interleukin (IL)-4 and Signal transducer and activator of transcription 6 (STAT6), which have been reported to play a role in the pathogenesis of inflammation and cancer, were evaluated in snake venom toxin (SVT)-induced apoptosis. Methods : Inflammation was induced in human HaCaT kerationocytes, by lipopolysaccharide (LPS; $1{\mu}g/mL$) or tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), followed by treatment with SVT (0, 1, or $2{\mu}g/mL$). Cell viability was assessed by MTT assays after 24 h, and the expression of levels of IL-4, STAT6, and the apoptosis-related proteins p53, Bax, and Bcl-2 were evaluated by western blotting. Electro mobility shift assays (EMSAs) were performed to evaluate the DNA binding capacity of STAT6. Results : MTT assays showed that inflammation-induced growth of HaCaT cells following LPS or TNF-${\alpha}$ stimulation was inhibited by SVT. Western blot analysis showed that p53 and Bax, which promote apoptosis, were increased, whereas that of Bcl-2, an anti-apoptotic protein, was decreased in a concentration-dependent manner in LPS- or TNF-${\alpha}$-induced HaCaT cells following treatment with SVT. Moreover, following treatment of HaCaT cells with LPS, IL-4 concentrations were increased, and treatment with SVT further increased IL-4 expression in a concentration-dependent manner. Western blotting and EMSAs showed that the phosphorylated form of STAT6 was increased in HaCaT cells in the context of LPS- or TNF-${\alpha}$-induced inflammation in a concentration-dependent manner, concomitant with an increase in the DNA binding activity of STAT6. Conclusion : SVT can effectively promote apoptosis in HaCaT cells in the presence of inflammation through a pathway involving IL-4 and STAT6.

• Biomolecules & Therapeutics
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• v.26 no.5
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• pp.464-473
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• 2018

Cripto is a small glycosylphosphatidylinositol-anchored signaling protein that can detach from the anchored membrane and stimulate proliferation, migration, differentiation, vascularization, and angiogenesis. In the present study, we demonstrated that Cripto positively affected proliferation and survival of mesenchymal stem cells (MSCs) without affecting multipotency. Cripto also increased expression of phosphorylated janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), 78 kDa glucose-regulated protein (GRP78), c-Myc, and cyclin D1. Notably, treatment with an anti-GRP78 antibody blocked these effects. In addition, pretreatment with STAT3 short interfering RNA (siRNA) inhibited the increase in p-JAK2, c-Myc, cyclin D1, and BCL3 levels caused by Cripto and attenuated the pro-survival action of Cripto on MSCs. We also found that incubation with Cripto protected MSCs from apoptosis caused by hypoxia or $H_2O_2$ exposure, and the level of caspase-3 decreased by the Cripto-induced expression of B-cell lymphoma 3-encoded protein (BCL3). These effects were sensitive to down-regulation of BCL3 expression by BCL3 siRNA. Finally, we showed that Cripto enhanced expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). In summary, our results demonstrated that Cripto activated a novel biochemical cascade that potentiated MSC proliferation and survival. This cascade relied on phosphorylation of JAK2 and STAT3 and was regulated by GRP78. Our findings may facilitate clinical applications of MSCs, as these cells may benefit from positive effects of Cripto on their survival and biological properties.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.626-632
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• 2005

A new bacterium BL-2 excreting a novel cationic polyglucosamine biopolymer was isolated from the spoiled leaves of Chinese cabbage and identified as Enterobacter sp. BL-2. The isolated Enterobacter sp. BL-2 was cultivated in pH-stat fed-batch culture using acetic acid as the feeding stock at pH 8.0, resulting in 17.11 g/l of cells and 1.53 g/l of an extracellular biopolymer after 72 h. The excreted biopolymer was purified by a three-step procedure, involving ethanol precipitation and deproteinizations, to a nearly homogeneous state, and its molecular weight was found to be 106 kDa. It was composed of glucosamine, rhamnose, and galactose at a molar ratio of 86.4:1.6:1.0, respectively, indicating a rarely found novel high-glucosamine-containing biopolymer. The FT-IR and $^{13}C-NMR$ spectra of the novel cationic polyglucosamine biopolymer PGB-l revealed a close identity with chitosan from crab shell. It can effectively flocculate various suspended solids, including kaolin clay, $Ca(OH)_2,\;Al_{2}O_3$, active carbon, microbial cells, and acidic dyes.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.3
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• pp.187-197
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• 2009

Objective: Phosphorylation and dephosphorylation of proteins are important in regulating cellular signaling pathways. Bead-based multiplex phosphorylation assay was conducted to detect the phosphorylation of seven proteins to maximize the information obtained from a single lysate of stage-specific mouse oocytes at a time. Methods: Cumulus-oocyte complexes (COCs) were cultured for 2 h, 8 h, and 16 h, respectively to address phosphorylation status of seven target proteins during oocyte maturation process. We analyzed the changes in phosphorylation at germinal vesicle (GV, 0 h), germinal vesicle breakdown (GVBD, 2 h), metaphase I (MI, 8 h), and metaphase II (MII, 16 h in vitro or in vivo) mouse oocytes by using Bio-Plex phosphoprotein assay system. We chose seven target proteins, namely, three mitogen-activated protein kinases (MAPKs), ERK1/2, JNK, and p38 MAPK, and other 4 well known signaling molecules, Akt, GSK-$3{\alpha}/{\beta}$, $I{\kappa}B{\alpha}$, and STAT3 to measure their phosphorylation status. Western blot analysis and kinase inhibitor treatment for ERK1/2, JNK, and Akt during in vitro maturation of oocytes were conducted for the confirmation. Results: Phosphorylation of ERK1/2, JNK, p38 MAPK and STAT3 was increased over 3 folds up to 20 folds, while phosphorylation of the other three signal molecules, Akt, GSK-$3{\alpha}/{\beta}$, and $I{\kapa}B{\alpha}$ was less than 3 folds. All of these results except for Akt were statistically significant (p<0.05). Conclusion: This is the first report on the new and valuable method measuring many phosphoproteins simultaneously in one minute sample such as oocyte lysates. All of the three MAPKs, ERK1/2, JNK, and p38 MAPK are involved in the process of mouse oocyte maturation. In addition, STAT3 might be important regulator of oocyte maturation, while Akt phosphorylation at Serine 473 may not be involved in the regulation of oocyte maturation.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.1
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• pp.11-18
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• 2020

The present study was aimed to explore the neuroprotective role of imatinib in global ischemia-reperfusion-induced cerebral injury along with possible mechanisms. Global ischemia was induced in mice by bilateral carotid artery occlusion for 20 min, which was followed by reperfusion for 24 h by restoring the blood flow to the brain. The extent of cerebral injury was assessed after 24 h of global ischemia by measuring the locomotor activity (actophotometer test), motor coordination (inclined beam walking test), neurological severity score, learning and memory (object recognition test) and cerebral infarction (triphenyl tetrazolium chloride stain). Ischemia-reperfusion injury produced significant cerebral infarction, impaired the behavioral parameters and decreased the expression of connexin 43 and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in the brain. A single dose administration of imatinib (20 and 40 mg/kg) attenuated ischemia-reperfusion-induced behavioral deficits and the extent of cerebral infarction along with the restoration of connexin 43 and p-STAT3 levels. However, administration of AG490, a selective Janus-activated kinase 2 (JAK2)/STAT3 inhibitor, abolished the neuroprotective actions of imatinib and decreased the expression of connexin 43 and p-STAT3. It is concluded that imatinib has the potential of attenuating global ischemia-reperfusion-induced cerebral injury, which may be possibly attributed to activation of JAK2/STAT3 signaling pathway along with the increase in the expression of connexin 43.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.753-759
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• 2002

$\beta$-Cyclodextrin glucanotransferase ($\beta$-CGTase) was overproduced extracellularly using recombinant E. coli by transforming the plasmid pECGT harboring a secretive signal peptide. The $\beta$-CGTase gene of alkalophilic Bacillus firmus var alkalophilus was inserted into the high expression vector pET20b(+) containing a secretive pelB signal peptide, and then transformed into E. coli BL2l(DE3)pLysS. The optimum culture conditions fer the overproduction of $\beta$-CGTase were determined to be TB medium containing 0.5% (w/v) soluble starch at post-induction temperature of $25^{\circ}C$. A significant amount of $\beta$-CGTase, up to 5.83 U/ml, which was nine times higher than that in the parent strain B. firmus var. alkalophilus, was overproduced in the extracellular compartment. A pH-stat fed-batch cultivation of the recombinant E. coli was also performed to achieve the secretive overproduction of $\beta$-CGTase at a high cell density, resulting in production of up to 21.6 U/ml of $\beta$-CGTase.