• Environmental Mutagens and Carcinogens
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• v.24 no.2
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• pp.99-107
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• 2004

The validation of many synthetic chemicals that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this respect, the regulation and evaluation of the chemical hazard playa very important role to environment and human health. The clastogenicity of 11 synthetic chemicals was evaluated in Chinese hamster lung (CHL) fibroblast in vitro. Benzoyl chloride (CAS No. 98-88-4) induced chromosomal aberrations with statistical significance at the concentration of 31-123 $\mug/ml$ and 43 $\mug/ml$ in the absence and presence of S-9 metabolic activation system, respectively. 2-Propyn-l-o1 (CAS No. 107-19-7) and 2-Phenoxy ethanol (CAS No. 122-99-6) revealed clastogenicity only at the highest concentration in the presence of S-9 mixture. However, 1-naphthol (CAS No. 90-15-3) which is one of the most cytotoxic chemical among 11 chemicals tested revealed no clastogenicity both in the presence and absence of S-9 metabolic activation system. From the results of chromosomal aberration assay with 11 synthetic chemicals in CHL fibroblast in vitro, Benzoyl chloride (CAS No. 98-88-4), 2-Propyn-l-01 (CAS No. 107-19-7) and 2-Phenoxy ethanol (CAS No. 122-99-6) revealed positive clastogenic results in this study.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.233-240
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• 2003

This study was conducted to examine the effects of oocyte maturation period, phytohemagglutinin-P (PHA-P) treatment and activation agent on the enucleation, fusion, activation or in vitro development of bovine nuclear transfer embryos. Bovine oocytes were enucleated at 16∼24 h of in vitro maturation (IVM). Adult ear skin cells treated or non-treated with PHA-P were transferred into enucleated oocytes. Reconstituted oocytes treated or non-treated with PHA-P were fused by a pulse of 1.5 kV/cm for 30 $\mu$sec. Fused oocytes were activated with a combination of calcium ionophore (A23187) and cycloheximide (CHXM) or dimethylaminopurine (DMAP), and cultured in vitro for 7∼9 days. Enucleation rate was significantly increased when oocytes were matured for 16∼18 h (70.2∼92.3%, P<0.05) compared to that of oocytes were matured for 20∼24 h (44.3∼53.4%). The location of metaphase-II plate was far off from the 1st polar body as maturation time was increased. PHA-P treatment of donor cells or reconstituted oocytes significantly improved fusion rate (P<0.05). Cleavage and blastocyst formation rates were significantly increased after activation with a combination of A23187 and DMAP (78.6% and 32.9%, respectively) compared to those of embryos activated with a combination of A23l87 and CHXM (48.5 and 15.2%, respectively). From the present result, it is suggested that high enucleation efficiency can obtained by using oocytes matured for 18 h. It also shows that PHA-P treatment can improve the fusion rate, and activation with a combination of A23187 and DMAP can enhance the embryo development.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3405-3409
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• 2013

The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.

• Animal cells and systems
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• v.5 no.4
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• pp.267-274
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• 2001

Calpains are a family of cysteine proteases existing primarily in two forms designated by the $Ca^{2+}$ concentration needed for activation in vitro, $\mu$-calpain (calpain-I) and m-calpain (calpain-II). The physiologica1 roles of calpains remain unclear. Many groups have proposed a role for calpains In apoptosis, but their patterns of activation are not well characterized. Calpains have been implicated in neutrophil apoptosis, glucocorticoid-induced thymocyte apoptosis, as well as many other apoptotic pathways. Calpain activation in apoptosis is usually linked upstream or downstream to caspase activation, or in a parallel pathway alongside caspase activation. Calpains have been suggested to be involved in DNA fragmentation (via endonuclease activation), but also as effector proteases that cleave cellular proteins involved in DNA repair, membrane associated proteins and other homeostatic regulatory proteins. Recently, our laboratory demonstrated $\mu$-calpain activation in NAD(P)H: quinone oxidoreducatse 1 (NQO1)-expressing cells after exposure to $\beta$-lapachone, a novel quinone and potential chemo- and radio-therapeutic agent. Increased cytosolic $Ca^{2+}$ in NQO1-expressing cells after $\beta$-lapachone exposures were shown to lead to $\mu$-calpain activation. In turn, $\mu$-calpain activation was important for substrate proteolysis and DNA fragmentation associated with apoptosis. Upon activation, $\mu$-calpain translocated to the nucleus where it could proteolytically cleave PARP and p53. We provided evidence that $\beta$-lapachone-induced, $\mu$-calpain stimulated, apoptosis did not involve any of the known caspases; known apoptotic caspases were not activated after $\beta$-lapachone treatment of NQO1-expressing cells, nor did caspase inhibitors have any effect on $\beta$-1apachone-induced cell death. Elucidation of processes by which $\beta$-1apachone-stimulated $\mu$-calpain activation and calpains ability to activate endonucleases and induce apoptosis independent of caspase activity will be needed to further develop/modulate $\beta$-lapachone for treatment of human cancers that over-express NQO1.

• Reproductive and Developmental Biology
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• v.31 no.2
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• pp.109-113
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• 2007

This study was conducted to evaluate the effect of cytochalasin B (CB) treatment in the activation medium on the development of somatic cell nuclear transfer (SCNT) rat embryos. Fetal fibroblast cells were isolated from a Day 14.5 fetus, and the oocytes for recipient cytoplasm were recovered from 4-week old Sprague Dawley rats. After enucleation and nuclear injection, the reconstructed oocytes were immediately exposed to activation medium consisting of 10 mM $SrCl_2$ with or without CB for 4 hr, and formation of pseudo-pronucleus (PPN) was checked at 18 hr after activation. Then, they were transferred into day 1 pseudopregnant recipients (Hooded Wistar) or cultured for 5 days to check their developmental competence in vivo or in vitro. The number of PPN was not affected by CB treatment during the activation. However, CB treatment supported pre-implantation development of rat SCNT embryos. Embryos generated by the procedures of SCNT were also capable of implanting, with 1 implantation scar found from a recipient following the transfer of 87 SCNT embryos to four foster mothers. The result of the present study shows that rat SCNT embryo can develop to post-implantation stage following treatment with CB.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.41-45
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• 2006

Electrical treatment has been widely used for porcine oocytes activation. However, developmental rates following electrical activation of porcine oocytes is relatively inefficient compared to other domestic animals. To investigate the effects of porcine oocytes on combined activation by both chemical and electrical treatment, in-vitro matured oocytes were activated by combined cycloheximide and electrical pulses treatment. Cumulus-free oocytes were exposed with NCSU-23 medium containing cycloheximide $(10{\mu}g/ml)$ for 0, 5, 10, 20, 30 min and then activated by electrical pulse treatment and cultured in PZM-3 for 8 days. Also effects of exposure to $6.25{\mu}M$ calcium ionophore for 2 min for cumulus-free oocytes were tested. The percentage of blastocyst formation in 10 min exposure to $10{\mu}g/ml$ cycloheximide and electrical pulse treatment was significantly increased (P<0.05) than in the control group. And exposure to $6.25{\mu}M$ calcium ionophore for 2 min with $10{\mu}g/ml$ cycloheximide for 10min and electrical pulse treatment significantly increased (P<0.05) the percentage of blastocyst developmental rates than the control group. In conclusion, activation by combined cycloheximide and electrical stimulation treatment promoted the subsequent development of porcine oocytes and improved the subsequence blastocyst development.

• The Korea Journal of Herbology
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• v.28 no.2
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• pp.1-7
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• 2013

Objectives : Sesamin, a major lignan in sesame seeds, has been reported to have neuroprotective effects against in vitro ischemia and in vivo MCAo-reperfusion cerebral ischemia model, however, there is no reports in an in vivo global cerebral ischemia model. The purpose of the study was to investigate the neuroprotective effect of sesamin in global cerebral ischemia induced by four-vessel occlusion (4-VO) in rats through inhibition of microglial activation in this model. Methods : The neuroprotective effects were investigated using a 10 min of 4-VO ischemia rat model by measuring intact pyramidal neurons in the CA1 region of the hippocampus using Nissle staining. The antiinflammatory or reducing neurotoxicity effect was investigated using immunohistochemisty, RT-PCR and western blot analysis of inflammatory or neurotoxic mediators. Results : Intraperitoneal injection of sesamin at doses of 0.3, 1.0, 3.0, and 10.0 mg/kg at 0 min and 90 min after ischemia conferred 26.6%, 30.1%, 42.5%, and 30.5% neuroprotection, respectively, compared to the vehicle-treated control group. A 3.0 mg/kg dose of sesamin inhibited microglia activation and consequently, cyclooxygenase-2, inducible nitric oxide, and interleukine-$1{\beta}$ expressions at 48 h after reperfusion. Conclusions : Sesamin protects neuronal cell death through inhibition of microglial activation or the production of neurotoxic metabolites and proinflammatory mediators by microglia such as COX-2, iNOS and IL-$1{\beta}$ in global cerebral ischemia.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.309-318
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• 2024

Compared to other organs, the brain has limited antioxidant defenses. In particular, the hippocampus is the central region for learning and memory and is highly susceptible to oxidative stress. Glial cells are the most abundant cells in the brain, and sustained glial cell activation is critical to the neuroinflammation that aggravates neuropathology and neurotoxicity. Therefore, regulating glial cell activation is a promising neurotherapeutic treatment. Quinic acid (QA) and its derivatives possess anti-oxidant and anti-inflammatory properties. Although previous studies have evidenced QA's benefit on the brain, in vivo and in vitro analyses of its anti-oxidant and anti-inflammatory properties in glial cells have yet to be established. This study investigated QA's rescue effect in lipopolysaccharide (LPS)-induced behavior impairment. Orally administering QA restored social impairment and LPS-induced spatial and fear memory. In addition, QA inhibited proinflammatory mediator, oxidative stress marker, and mitogen-activated protein kinase (MAPK) activation in the LPS-injected hippocampus. QA inhibited nitrite release and extracellular signal-regulated kinase (ERK) phosphorylation in LPS-stimulated astrocytes. Collectively, QA restored impaired neuroinflammation-induced behavior by regulating proinflammatory mediator and ERK activation in astrocytes, demonstrating its potential as a therapeutic agent for neuroinflammation-induced brain disease treatments.

• Toxicological Research
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• v.21 no.1
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• pp.57-62
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• 2005

To investigate the mutant induction of wild ginseng culture extract, we performed chromosomal aberration assay with chinese hamster lung cell in vitro. The test concentration of the extract was decided for the standard with the 50% suppression of cell propagation in the cell. The concentrations for the chromosome test were 1,250, 2,500 and 5,000 ㎍/ml with metabolic activation (+S, 6 hours treatment), 1,100, 2,200 and 4,400 ㎍/ml without metabolic activation (-S, 6 hours treatment) 800, 1,600 and 3,200 ㎍/ml without metabolic activation (-S, 24 hours treatment). No significant increase in chromosome aberrations was observed at any of these concentrations both in the absence and presence of metabolic activation system. Cyclophosphamide monohydrate (CPA) and ethylmethanesulfonate (EMS) caused a significant increase in chromosome aberration. These results may be concluded that wild ginseng culture extract is not capable of inducing chromosome aberration in cultured chinese hamster lung cell regardless of metabolic activation and genotoxicity of that is negative under the present experimental condition.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.492-498
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• 2005

The mechanism of activation of phospholipase D2 (PLD2) remains undefined although mechanisms have been described for the activation of PLDI. By expression of mutated forms of haemaglutinnin-tagged PLD2 in a mast cell (RBL-2H3) line, we show that PLD2 is phosphorylated at tyrosines -11, -14, and -470 and that tyrosine-470 is critical for activation of PLD2 by antigen. Studies were performed with mutated-DNA constructs for haemaglutinnin-tagged PLD2 in which codons for tyrosine -11, -14, -165, and -470 were mutated to phenylalanine either individually or collectively. Transient expression of these constructs showed that mutation of tyrosine -11, -14, -470, or all tyrosines (all-mutated PLD2) suppressed antigen-induced tyrosine phosphorylation of PLD2 but only the tyrosine-470 mutant failed to be activated by antigen as assessed by in vitro assay of immunoprepitated PLD2 or by assay of PLD in intact cells. The critical role of tyrosine-470 was confirmed in studies with add-back mutants (phenylalanine back to tyrosine) of the all-mutated PLD. The findings provide the first description of a mechanism of activation of PLD2 in a physiological setting.