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Abstract
In previous studies, the ethanol extract of cactus (Opuntia ficus-indica) showed potent anti-inflammatory action. In the present study, following fractionation of the methanol extract of cactus stems guided by adjuvant-induced chronic inflammation model in mice, an active anti-inflammatory principle has been isolated and identified as beta-sitosterol.
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Abstract
The effects of ethanolic extract (EEP) of propolis on chronic inflammation were evaluated using rat adjuvant arthritis. In the chronic inflammatory animal model, the arthritis index was suppressed by EEP treatments (50 mg/kg/day and 100 mg/kg/day, p.o.). Moreover, physical weakness, induced by the chronic disease state, was dose-dependently improved in the EEP-treated groups. Its analgesic effect, assessed using the tail-flick test, was comparable to prednisolone (2.5 mg/kg/day, p.o.) and acetyl salicylic acid (100 mg/kg/day, p.o.). In carrageenan rat hind paw edema, which was conducted to test the effects of subfractions of EEP, the petroleum ether sub-fraction (100 mg/kg, p.o.) showed an inhibitory effect on the paw edema whereas EEP (200 mg/kg, p.o.) showed a significant anti-inflammatory effect at 3 and 4 hrs after carrageenan injection. From these results, we conclude that the ethanolic extract of propolis had a profound anti-inflammatory effects on both chronic and acute inflammations.
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Park EH, Zaks MA, Kurths J. Phase synchronization in the forced Lorenz system. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1999; 60:6627-38. [PMID: 11970583 DOI: 10.1103/physreve.60.6627] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/1999] [Indexed: 11/07/2022]
Abstract
We demonstrate that the dynamics of phase synchronization in a chaotic system under weak periodic forcing depends crucially on the distribution of intrinsic characteristic times of this system. Under the external periodic action, the frequency of every unstable periodic orbit is locked to the frequency of the force. In systems which in the autonomous case displays nearly isochronous chaotic rotations, the locking ratio is the same for all periodic orbits; since a typical chaotic orbit wanders between the periodic ones, its phase follows the phase of the force. For the Lorenz attractor with its unbounded times of return onto a Poincaré surface, such state of perfect phase synchronization is inaccessible. Analysis with the help of unstable periodic orbits shows that this state is replaced by another one, which we call "imperfect phase synchronization," and in which we observe alternation of temporal segments, corresponding to different rational values of frequency lockings.
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George ER, Sullivan TM, Park EH. Thermoplastic starch blends with a poly(ethylene-co-vinyl alcohol): Processability and physical properties. POLYM ENG SCI 1994. [DOI: 10.1002/pen.760340107] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Takagi K, Park EH, Kato H. Anti-inflammatory activities of hederagenin and crude saponin isolated from Sapindus mukorossi Gaertn. Chem Pharm Bull (Tokyo) 1980; 28:1183-8. [PMID: 7418110 DOI: 10.1248/cpb.28.1183] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Park EH, Shin YM, Lim YY, Kwon TH, Kim DH, Yang MS. Expression of glucose oxidase by using recombinant yeast. J Biotechnol 2000; 81:35-44. [PMID: 10936658 DOI: 10.1016/s0168-1656(00)00266-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The glucose oxidase gene (GO) of Aspergillus niger was cloned into the yeast shuttle vector YEp352 with combinations of various promoters and terminators, and then used to transform Saccharomyces cerevisiae. Expressed GO was successfully secreted into culture medium due to the presence of the intrinsic signal peptide of GO. Four different promoters fused to GO were tested: bidirectional galactose dehydrogenase 1 and 10 (GAL1, GAL10) promoters, glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter and an yeast hybrid ADH2-GPD promoter consisting of alcohol dehydrogenase II (ADH2) and GPD promoter. The intrinsic terminator of GO as well as the GAL7 terminator were also compared for better production of GO. Deletion of most of the terminating region from GO yielded only a slight amount of GO while the presence of either terminator greatly increased GO production. The GAL10 promoter produced the least amount of GO, GAL1 and GPD promoters were moderate, and the ADH2-GPD hybrid promoter was the best among all tested. However, the hybrid promoter was tightly regulated by the presence of an excess amount of either glucose or ethanol, and it appeared that 2% glucose and 1. 5% ethanol supplement was the best concentration for GO production. It was possible to produce 260 IU ml(-1) of GO, an equivalent of 5 g l(-1), under the presence of 2% glucose and 1.5% ethanol. UV mutagenesis of a recombinant S. cerevisiae was also applied and it further increased the yield of GO to 460 IU ml(-1) under the presence of 2% glucose and 1.5% ethanol without any changes in cell growth. Corn steep liquor which is commonly used in bioindustry is a good alternative substrate for high priced glucose for the hybrid promoter and suggests a cost effective means for commercial mass production of GO using recombinant yeast.
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Comparative Study |
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Lee JS, Miya M, Lee YS, Kim CG, Park EH, Aoki Y, Nishida M. The complete DNA sequence of the mitochondrial genome of the self-fertilizing fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) and the first description of duplication of a control region in fish. Gene 2001; 280:1-7. [PMID: 11738812 DOI: 10.1016/s0378-1119(01)00765-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We isolated Rivulus marmoratus mitochondrial DNA by long-polymerase chain reaction with conserved primers, and sequenced it with 36 sets of internal conserved primers, which were designed from the extensive sequence similarities of mitochondrial DNA from several fish species. The R. marmoratus mitochondrial DNA has 17,329 bp with a conserved structural organization compared to those of other fish. Rivulus marmoratus mitochondrial DNA also has two nearly identical control regions. The basic characteristics of the R. marmoratus mitochondrial genome are discussed.
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Lee Y, Kim SJ, Park HD, Park EH, Huang SM, Jeon SB, Kim JM, Lim DS, Koh SS. PAUF functions in the metastasis of human pancreatic cancer cells and upregulates CXCR4 expression. Oncogene 2009; 29:56-67. [PMID: 19784070 DOI: 10.1038/onc.2009.298] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pancreatic cancer is characterized by early metastatic spread, but the process of tumor cell dissemination is largely unknown. In this study we show that the soluble protein pancreatic adenocarcinoma upregulated factor (PAUF) has an important role in the metastasis and progression of the disease. Variations in the level of PAUF, either by overexpression or knockdown, resulted in altered migration, invasion and proliferation capacity of pancreatic cancer cells. Moreover, depletion of PAUF in metastatic cells dramatically abrogated the spread of the cells to distant organs in an orthotopic xenograft mouse model. PAUF elicited the activation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and AKT intracellular signaling cascades and consequently their downstream transcription factors in an autocrine manner. Genome-wide expression analysis revealed that C-X-C chemokine receptor type 4 (CXCR4) expression was induced by PAUF overexpression but was repressed by PAUF knockdown. The PAUF-mediated increase in cancer cell motility was attenuated by the CXCR4 inhibitor, AMD3100, or by anti-CXCR4 antibody. Furthermore, immunohistochemical analysis of pancreatic tumor tissues clearly showed a significant positive correlation between PAUF and CXCR4 expression. Collectively, these findings indicate that PAUF enhances the metastatic potential of pancreatic cancer cells, at least in part, by upregulating CXCR4 expression.
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Research Support, Non-U.S. Gov't |
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Park EH, Kahng JH, Paek EA. Studies on the pharmacological action of cactus: identification of its anti-inflammatory effect. Arch Pharm Res 1998; 21:30-4. [PMID: 9875511 DOI: 10.1007/bf03216749] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The ethanol extracts of Opuntia ficus-indica fructus (EEOF) and Opuntia ficus-indica stem (EEOS) were prepared and used to evaluate the pharmacological effects of cactus. Both the extracts inhibited the writhing syndrome induced by acetic acid, indicating that they contains analgesic effect. The oral administrations of EEOF and EEOS suppressed carrageenan-induced rat paw edema and also showed potent inhibition in the leukocyte migration of CMC-pouch model in rats. Moreover, the extracts suppressed the release of beta-glucuronidase, a lysosomal enzyme in rat neutrophils. It was also noted that the extracts showed the protective effect on gastric mucosal layers. From the results it is suggested that the cactus extracts contain anti-inflammatory action having protective effect against gastric lesions.
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Abstract
The methanolic extract of Opuntia ficus-indica stems and its hexane, ethyl acetate, n-butanol and aqueous fractions were evaluated for their wound healing activity in rats. The extract and less polar fractions showed significant effects.
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Park EH, Kim DS. A procedure for staining cartilage and bone of whole vertebrate larvae while rendering all other tissues transparent. STAIN TECHNOLOGY 1984; 59:269-72. [PMID: 6390784 DOI: 10.3109/10520298409113869] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A new procedure for clearing and differentially staining skeletons of vertebrate larvae is described. body pigments of fixed specimens are bleached by treatment with alkaline H2O2. This process markedly enhances the transparency of alcian blue-alizarine red S stained whole animals without damaging the specimens. This procedure should be useful for analyzing skeletal structures in studies of embryology, comparative anatomy and teratology of small vertebrates.
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Song YS, Jin C, Park EH. Identification of metabolites of phytosterols in rat feces using GC/MS. Arch Pharm Res 2000; 23:599-604. [PMID: 11156182 DOI: 10.1007/bf02975248] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Beta-sitosterol, campesterol and stigmasterol have been known to the phytosterols the most frequently found in plants. Metabolism of phytosterols was investigated using rat feces and liver microsomes. Feces were collected after phytosterols (a well characterized mixture of beta-sitosterol 40%, campesterol 30% and dihydrobrasicasterol) were administered orally (0.5 g/kg) to rats. Metabolites of phytosterols were identified using GC/MS. Three peaks were eluted at 12.47, 12.65, 12.87 min and had characteristic molecular ions m/z 428, 430, 432, respectively. Three fecal metabolites were identified as androstadienedione, androstenedione, and androstanedione. No metabolites could be detected in the rat liver microsomal reaction mixture. The results suggest that the metabolites of phytosterols in rat feces are formed by oxidation at 3- position, saturation at 5- and 6- position, and 17- side chain cleavage in the rat large intestine.
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Kim TH, Lee JY, Lee HM, Lee SH, Cho WS, Ju YH, Park EH, Kim KW, Lee SH. Remodelling of nasal mucosa in mild and severe persistent allergic rhinitis with special reference to the distribution of collagen, proteoglycans, and lymphatic vessels. Clin Exp Allergy 2010; 40:1742-54. [PMID: 20860724 DOI: 10.1111/j.1365-2222.2010.03612.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen, and lymphangiogenesis are involved in tissue remodelling of various organs with inflammatory diseases. OBJECTIVE We determined the expression level and the distribution pattern of small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa. METHODS The distribution pattern of collagen, proteoglycans, and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa was evaluated by the van Gieson staining, immunohistochemistry, RT-PCR, and Western blotting. Quantitative analyses of collagen deposition were calculated as the median of the total percentage area in the tissue specimen. For the evaluation of proteoglycans, the percentage area stained and median optical density were measured for each image. Lymphatic vessels were identified by D2-40 antibody and calculated using the lymphatic vessel density and endothelial length density in tissue specimens. The expression of MMP 2 and 9, TIMP1 and 2 was evaluated with RT-PCR and Western blotting. RESULTS In mild and severe persistent allergic nasal mucosa, compared with healthy nasal mucosa, collagen showed more intense staining in the superficial and submucosal layer. In healthy and allergic nasal mucosa, decorin was lightly stained without significant differences in the percentage area and optical density of staining. However, lumican and biglycan showed strong immunoreactivity in mild and severe persistent allergic nasal mucosa, which was verified by Western blotting. The number and endothelial length density of lymphatic vessels were increased in mild and severe persistent allergic nasal mucosa compared with healthy nasal mucosa. The expression of MMP 9 was increased in severe persistent allergic rhinitis. CONCLUSION AND CLINICAL RELEVANCE These results suggest that the altered distribution pattern of collagen, proteoglycans, and lymphatic vessels could potentially modulate the remodelling of nasal mucosa in mild and severe persistent allergic nasal mucosa.
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Journal Article |
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Park JH, Lee JJ, Yoon S, Lee JS, Choe SY, Choe J, Park EH, Kim CG. Genomic cloning of the Hsc71 gene in the hermaphroditic teleost Rivulus marmoratus and analysis of its expression in skeletal muscle: identification of a novel muscle-preferred regulatory element. Nucleic Acids Res 2001; 29:3041-50. [PMID: 11452029 PMCID: PMC55811 DOI: 10.1093/nar/29.14.3041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2001] [Revised: 05/31/2001] [Accepted: 05/31/2001] [Indexed: 11/13/2022] Open
Abstract
To further our understanding of the role of stress proteins in development as well as in adaptation of fish to adverse environmental conditions, we undertook molecular analyses of stress protein encoding genes from the hermaphroditic teleost Rivulus marmoratus. We isolated a genomic clone containing the Hsc71 gene (rm-hsc71m) and its upstream sequences. rm-Hsc71m is not induced by external stress, but is enriched in a tissue-specific manner during early development. In adult, the strongest expression appeared in skeletal muscle, whereas lower expression was seen in the gill, eye and brain. To understand the regulatory basis of high muscle expression of rm-hsc71m, transfection of R.marmoratus muscle tissue was performed using 5' deletion fragments containing the rm-hsc71m promoter driving EGFP expression. An upstream region from -2.7 to -1.9 kb was identified as a muscle-specific regulatory region. Within this region, we identified at least three sites with the novel sequence TGTnACA interacting with a fish muscle factor having an M(r) of 32 000. Our data indicate that rm-hsc71m expression in skeletal muscle is controlled by a muscle-specific regulatory element containing this novel motif.
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research-article |
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Park EH, Chang HH, Lee KC, Kweon HS, Heo OS, Ha KW. High frequency of thyroid tumor induction by N-methyl-N'-nitro-N-nitrosoguanidine in the hermaphroditic fish Rivulus marmoratus. Jpn J Cancer Res 1993; 84:608-15. [PMID: 8340250 PMCID: PMC5919321 DOI: 10.1111/j.1349-7006.1993.tb02020.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the self-fertilizing hermaphroditic fish, Rivulus marmoratus, the susceptibility to tumor induction by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was evaluated. Seven-day-old fish larvae were exposed for 2 h to MNNG at concentrations ranging from 5 to 25 ppm in a static water bath. The exposed fish were observed at 2 and 4 months after carcinogen treatment to assess tumor development. Within 4 months after 25 ppm MNNG exposure, nearly all fish developed thyroid tumors. The tumor incidences were dose- and time-dependent, and the latent period of tumor induction was less than 2 months. Most induced neoplasms were papillary carcinomas similar histologically to those of rodents and humans, and the tumors were serially transplantable to other fish of the same species. These results demonstrate that rivulus could be useful as a model of thyroid carcinogenesis.
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research-article |
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Burr JG, Park EH, Chan A. Nature of the reactive species in the photohydration of uracil and cytosine derivatives. J Am Chem Soc 1972; 94:5866-72. [PMID: 5053864 DOI: 10.1021/ja00771a054] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Park EH, Park EH, Cho IR, Srisuttee R, Min HJ, Oh MJ, Jeong YJ, Jhun BH, Johnston RN, Lee S, Koh SS, Chung YH. CUG2, a novel oncogene confers reoviral replication through Ras and p38 signaling pathway. Cancer Gene Ther 2010; 17:307-14. [PMID: 20075984 DOI: 10.1038/cgt.2009.83] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
As we have recently found a novel oncogene, the cancer-upregulated gene 2 (CUG2), which was elevated in a variety of tumor tissues such as the ovary, liver, lung and pancreas, we examined whether reovirus could efficiently induce cytolysis in cancer cells expressing CUG2 and thus be used as a potential cancer therapeutic agent. In this study, we describe experiments in which we use reovirus to treat NIH3T3 cells stably expressing either CUG2 (NIH-CUG2) or vector only (NIH-Vec). NIH-CUG2 cells readily support reoviral proliferation and undergo apoptosis, whereas NIH-Vec cells are highly resistant to reoviral infection and virus-induced apoptosis. This notable result may be explained by the observation that CUG2 expression inhibits PKR activation, leading to reoviral proliferation in nonpermissive NIH3T3 cells. Furthermore, reovirus infection results in almost complete regression of tumorgenic NIH-CUG2 cells in transplanted nude mice. As we found that CUG2 enhances activation of MAPK (ERK, JNK and p38), Src kinase and Ras, we examined whether CUG2 confers reoviral replication independent of the Ras or p38 MAPK signaling pathway. From these experiments we found that either inhibition of p38 MAPK or Ras blocks reoviral proliferation even in the presence of CUG2 but inhibition of ERK, JNK and Src kinase does not, indicating that activation of p38 MAPK and Ras has critical roles in reoviral replication in CUG2-expressing tumor cells. Accordingly, we propose that reovirus can be useful in the treatment of transformed cells expressing CUG2, which is commonly detected in various tumor tissues.
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Research Support, Non-U.S. Gov't |
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Burr JG, Gordon BR, Park EH. THE MECHANISM OF PHOTOHYDRATION OF URACIL AND N-SUBSTITUTED URACILS. Photochem Photobiol 1968. [DOI: 10.1111/j.1751-1097.1968.tb05847.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Park EH, Kang YS. Karyological confirmation of conspicuous ZW sex chromosomes in two species of Pacific anguilloid fishes (Anguilliformes: Teleostomi). CYTOGENETICS AND CELL GENETICS 1979; 23:33-8. [PMID: 761483 DOI: 10.1159/000131299] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Leukocyte and kidney cell cultures were used to examine the sex chromosomes of Japanese freshwater eels (Anguilla japonica) and conger eels (Astroconger myriaster). The conspicuous presence of ZW sex chromosomes, due to a drastic reduction in size of the W, was confirmed in both species, where the Z was the largest metacentric and the W was the smallest metacentric in a diploid karyotype of 38 chromosomes in both species. These species are the first examples of the ZW type of heteromorphism in eels.
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Laughlin TF, Lubinski BA, Park EH, Taylor DS, Turner BJ. Clonal stability and mutation in the self-fertilizing hermaphroditic fish, Rivulus marmoratus. J Hered 1995; 86:399-402. [PMID: 7560876 DOI: 10.1093/oxfordjournals.jhered.a111610] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Previous investigations of natural populations of the hermaphroditic, self-fertilizing fish species Rivulus marmoratus demonstrated a surprising amount of interclonal differentiation among highly polymorphic "DNA fingerprint" loci. The genetic differentiation observed among clones was thought to be the effect of extreme population mixing because of high rates of migration and population extinction. It was demonstrated that mutation rates at hypervariable loci would have to exceed 10(-4) on average to alone account for the observed interclonal differences. The present study reports that, among laboratory lines of this species, mutation rates at the most unstable set of hypervariable loci are not greater than 3.52 x 10(-4), and are probably lower. Mutation rates at several other sets of loci are even lower. A field transplantation study demonstrated complete clonal stability over several generations. These results suggest that the high interclonal differences observed in natural populations of this species is not caused by a generally higher rate of mutation at these specific loci.
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Cho HJ, Park EH, Bae MA, Kim JK. Expression of mRNAs for preprotachykinin and nerve growth factor receptors in the dorsal root-ganglion following peripheral inflammation. Brain Res 1996; 716:197-201. [PMID: 8738239 DOI: 10.1016/0006-8993(96)00026-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nerve growth factor (NGF) plays a dynamic role in the control of substance P (SP) levels and synthesis in the dorsal root ganglion (DRG). In the present study, in situ hybridization was used to examine the change of preprotachykinin (PTT), trkA and p75 mRNAs levels in the DRG after the injection of complete Freund's adjuvant into the hindpaws of rats. Peripheral tissue inflammation increased PTT and p75 mRNAs levels in the DRG, while trkA mRNA levels showed no change. These findings suggest that p75, in addition to trkA, also may be important in mediating the action of NGF on the synthesis of SP in the DRG following peripheral inflammation.
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Offen HW, Park EH. Effect of Pressure on the π—π* Absorption Spectra of Anthracene, Acridine, and Phenazine. J Chem Phys 1965. [DOI: 10.1063/1.1697033] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Park EH, Yi AK. Photoreactivation rescue and dark repair demonstrated in UV-irradiated embryos of the self-fertilizing fish Rivulus ocellatus marmoratus (Teleostei; Aplocheilidae). Mutat Res 1989; 217:19-24. [PMID: 2911263 DOI: 10.1016/0921-8777(89)90031-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of photoreactivation (PR) rescue and dark repair on the survival of UV-irradiated embryos of the hermaphroditic fish (Rivulus ocellatus marmoratus) are reported. When UV-irradiated embryos were illuminated by photoreactivating light (PRL) from fluorescent lamps, survival at the hatching stage was markedly increased. The maximum recovery to UV damage was shown by embryos that were exposed to PRL for at least 6 h after UV irradiation. The effect of PRL decreased 30 min after UV irradiation and no PR rescue was detected beyond 96 h. Treatment with 2 mM caffeine for 48 h after UV irradiation increased the sensitivity of the embryos in the dark. The above results demonstrate that Rivulus embryos have an efficient PR system and a caffeine-sensitive dark repair capacity.
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Kim HG, Park KN, Cho YW, Park EH, Fuchs JA, Lim CJ. Characterization and regulation of glutathione S-transferase gene from Schizosaccharomyces pombe. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1520:179-85. [PMID: 11513961 DOI: 10.1016/s0167-4781(01)00265-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A glutathione S-transferase (GST) gene has been cloned from Schizosaccharomyces pombe for the first time. The nucleotide sequence determined was found to contain 2030 base pairs including an open reading frame of 229 amino acids that would encode a protein of a molecular mass of 27017 Da. The cloned GST gene was expressed and was found to function in S. pombe, Saccharomyces cerevisiae, and Escherichia coli. The plasmid pGT207 encoding the S. pombe GST gene appeared to be able to accelerate the growth of a wild type S. pombe culture. In a culture of S. pombe containing plasmid pGT207, the growth was inhibited less by mercuric chloride than in a culture with vector alone. The 1088 bp region upstream from the GST gene as well as the region encoding the N-terminal 14 amino acids was transferred into the promoterless beta-galactosidase gene of plasmid YEp357R to yield the fusion plasmid pYSH2000. beta-Galactosidase synthesis was induced by cadmium chloride, mercuric chloride, hydrogen peroxide, and menadione. It was also induced by high temperature. These results suggest that the cloned S. pombe GST gene is involved in the oxidative stress response.
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Comparative Study |
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Park EH, Grimm H. Distribution of C-band heterochromatin in the ZW sex chromosomes of European and American eels (Anguillidae, Teleostomi). CYTOGENETICS AND CELL GENETICS 1981; 31:167-74. [PMID: 6173168 DOI: 10.1159/000131642] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The ZW sex chromosomes of the European eel, Anguilla anguilla, and the American eel, A. rostrata, were examined with C-band and fluorescent staining to demonstrate the C-band heterochromatin. The W as well as Z chromosomes in both species are C-band negative except for a small amount of C-band heterochromatin in the centromeric region, in contrast to the W or Y elements of most other vertebrates. No fluorescing W-associated body is evident either in interphase nuclei or in metaphase plates. The ZW chromosomes of the two species have substantially similar size, morphology, and patterns of C-band heterochromatin. Karyologic and evolutionary implications are discussed.
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