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21.
Suh YH Kim MK Shin YK Kim SH Oh KI Gil M Kim MK Choi YL Jung KC Lee KM Lee IS Park SH 《Molecules and cells》2002,13(2):237-244
Hodgkin's disease (HD) is a lymphoid neoplasm characterized by a low frequency of malignant giant tumor cells, known as Hodgkin's and Reed-Sternberg (HRS) cells. Sequence analysis of the immunoglobulin heavy chain hypervariable region (IgH V) genes of HRS cells revealed multiple nucleotide substitutions, indicating somatic mutations, and suggested that HRS cells originate from germinal center B cells or their progeny. We previously reported that CD99-antisense transfected B cell lines led to the generation of cells with a HRS phenotype. Because it is considered that HRS cells in HD carry somatic mutations of the IgH genes, we assume that somatic mutation may take place in the IgH genes of HRS-like cells which do not express CD99. Here we report that CD99 downregulated BJAB cell line has several mutations in IgH V genes. The frequency of mutation was 5.2 x 10(-4) mut.bp(-1) out of total sequenced cell clones. On the contrary, control vector transfected BJAB cell line or CD99 downregulated IM9 cell line did not show any mutations on single strand conformational polymorphism (SSCP) and sequence analysis. We expect that the analysis of the mutation pattern of the CD99-deficient BJAB cell line might be the basis for the understanding of the molecular and cellular mechanism that regulate somatic mutation and B cell selection. 相似文献
22.
Lee YS Jin DQ Park SH Han SY Kim HS Jeong TC Huh K Kim JA 《Free radical research》2002,36(12):1283-1289
Oxidative stress has been known to be involved in the mechanism of toxic effects of various agents on many cellular systems. In this study we investigated the role of reactive oxygen species (ROS) in 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD)-induced neuronal cell toxicity using SK-N-SH human neuroblastoma cells. TCDD inhibited proliferation of the cells in a dose-dependent manner, which was revealed by MTT staining, counting of cells stained with trypan blue and [ 3 H]thymidine uptake assay. TCDD also suppressed the basal generation of ROS in a time- and concentration-dependent manner assessed by 2',7'-dichlorofluorescein fluorescence. In addition, TCDD induced a dose-dependent inhibition of lipid peroxidation, a biomarker of oxidative stress, whereas it significantly increased the level of glutathione (GSH), an intracellular free radical scavenger in the cells. Moreover, TCDD altered the activities of major antioxidant enzymes; increase in superoxide dismutase (SOD) and catalase, but decrease in glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Red). Pretreatment with l -buthionine- S , R -sulfoximine (BSO, 50 μM), an inhibitor of GSH synthesis, significantly prevented the TCDD-induced reduction in lipid peroxidation and cell proliferation. Interestingly, exogenous application of an oxidant, H 2 O 2 (50 μM) markedly restored the inhibited cell proliferation induced by TCDD. Taken together, these results suggest that alteration of cellular redox balance may mediate the TCDD-induced inhibition of proliferation in human neuronal cells. 相似文献
23.
Lee MH Kim YW Kim TJ Park CS Kim JW Moon TW Park KH 《Biochemical and biophysical research communications》2002,295(4):818-825
The gene previously designated as putative cyclodextrinase from Thermotoga maritima (TMG) was cloned and overexpressed in Escherichia coli. The recombinant TMG was partially purified and its enzymatic characteristics on various substrates were examined. The enzyme hydrolyzes various maltodextrins including maltotriose to maltoheptaose and cyclomaltodextrins (CDs) to mainly glucose and maltose. Although TMG could not degrade pullulan, it rapidly hydrolyzes acarbose, a strong amylase and glucosidase inhibitor, to acarviosine and glucose. Also, TMG initially hydrolyzes p-nitrophenyl-alpha-pentaoside to give maltopentaose and p-nitrophenol, implying that the enzyme specifically cleaves a glucose unit from the reducing end of maltooligosaccharides unlike to other glucosidases. Since its enzymatic activity is negligible if alpha-methylglucoside is present in the reducing end, the type of the residue at the reducing end of the substrate is important for the TMG activity. These results support the fact that TMG is a novel exo-acting glucosidase possessing the characteristics of both CD-/pullulan hydrolyzing enzyme and alpha-glucosidase. 相似文献
24.
Summary. Down syndrome (DS) is the most significant genetic disorder with mental retardation and is caused by trisomy 21. The phenotype
of DS is thought to result from overexpression of a gene(s) located on the triplicated chromosome (region). An increasing
body of evidence that challenge this “gene dosage effect” hypothesis, however, has been reported indicating that this hypothesis
still remains to be elucidated. The availability of the complete sequence of genes on chromosome 21 could have an immediate
impact on DS research, but no conclusions can be drawn from nucleic acid levels. This made us evaluate protein levels of six
proteins, gene products, encoded on chromosome 21 (T-cell lymphoma invasion and metastasis inducing Tiam1 protein, holocarboxylase
synthetase, human interferon-regulated resistance GTP-binding protein MxA, Pbx regulating protein 1, autoimmune regulator,
and pericentrin) in fetal cortex from DS and controls at 18–19 weeks of gestational age using Western blot technique. None
of the investigated proteins showed overexpression in DS compared to controls. Our present data showing unaltered expression
of six proteins on chromosome 21 in fetal DS brain suggest that the existence of the trisomic state is not involved in abnormal
development of fetal DS brain and that the gene dosage effect hypothesis is not sufficient to fully explain the DS phenotype.
We are in the process of quantifying all gene products of chromosome 21 and our first results do not support the gene dosage
hypothesis.
Received June 27, 2002 Accepted July 19, 2002 Published online November 14, 2002
Authors' address: Prof. Dr. Gert Lubec, CChem, FRSC (UK), Department of Pediatrics, University of Vienna, Waehringer Guertel 18, A-1090 Vienna,
Austria, Fax: +43-1-40400-3194, E-mail: gert.lubec@akh-wien.ac.at
Abbreviations: AIRE, autoimmune regulator; DS, Down syndrome; HCS, holocarboxylase synthetase; Prep1, Pbx regulating protein 1; Tiam1, T-cell
lymphoma invasion and metastasis 1 相似文献
25.
Byung Young Park Hyunghee Lee Sangee Woo Miso Yoon Jeongjun Kim Yeonhee Hong Hee Suk Lee Eun Kyu Park Jong Cheon Hahm Jin Woo Kim Soon Shik Shin Min-Young Kim Michung Yoon 《PloS one》2015,10(11)
It has been suggested that angiogenesis modulates adipogenesis and obesity. This study was undertaken to determine whether ALS-L1023 (ALS) prepared by a two-step organic solvent fractionation from Melissa leaves, which exhibits antiangiogenic activity, can regulate adipose tissue growth. The effects of ALS on angiogenesis and extracellular matrix remodeling were measured using in vitro assays. The effects of ALS on adipose tissue growth were investigated in high fat diet-induced obese mice. ALS inhibited VEGF- and bFGF-induced endothelial cell proliferation and suppressed matrix metalloproteinase (MMP) activity in vitro. Compared to obese control mice, administration of ALS to obese mice reduced body weight gain, adipose tissue mass and adipocyte size without affecting appetite. ALS treatment decreased blood vessel density and MMP activity in adipose tissues. ALS reduced the mRNA levels of angiogenic factors (VEGF-A and FGF-2) and MMPs (MMP-2 and MMP-9), whereas ALS increased the mRNA levels of angiogenic inhibitors (TSP-1, TIMP-1, and TIMP-2) in adipose tissues. The protein levels of VEGF, MMP-2 and MMP-9 were also decreased by ALS in adipose tissue. Metabolic changes in plasma lipids, liver triglycerides, and hepatic expression of fatty acid oxidation genes occurred during ALS-induced weight loss. These results suggest that ALS, which has antiangiogenic and MMP inhibitory activities, reduces adipose tissue mass in nutritionally obese mice, demonstrating that adipose tissue growth can be regulated by angiogenesis inhibitors. 相似文献
26.
Myung Soo Park Seung-Yoon Oh Hae Jin Cho Jonathan J. Fong Woo-Jae Cheon Young Woon Lim 《Antonie van Leeuwenhoek》2014,106(4):593-603
A new species, Trichoderma songyi, was found to be associated with the pine mushroom (Tricholoma matsutake) in Korea. This species was isolated from three different substrates: Tricholoma matsutake basidiomata, as well as roots of Pinus densiflora and soil in the fairy ring. Based on its molecular and phenotypic characteristics, we demonstrate that Trichoderma songyi is unique and distinguishable from closely related species. We performed phylogenetic analyses based on two molecular markers, the genes for both translation elongation factor 1-alpha and the second largest subunit of RNA polymerase II. Phylogenetic analyses showed that Trichoderma songyi is closely related to Trichoderma koningii aggregate and Trichoderma caerulescens. Morphologically, Trichoderma songyi can be distinguished from these closely related taxa by its growth rates, colony morphology on PDA in darkness, and coconut-like odour. Due to the economic importance of the pine mushroom, the relationship between Trichoderma songyi and Tricholoma matsutake should be studied further. 相似文献
27.
Engineering of a butyraldehyde dehydrogenase of Clostridium saccharoperbutylacetonicum to fit an engineered 1,4‐butanediol pathway in Escherichia coli 下载免费PDF全文
28.
S Patyar R Joshi DS Prasad Byrav A Prakash B Medhi BK Das 《Journal of biomedical science》2010,17(1):21
Resistance to conventional anticancer therapies in patients with advanced solid tumors has prompted the need of alternative
cancer therapies. Moreover, the success of novel cancer therapies depends on their selectivity for cancer cells with limited
toxicity to normal tissues. Several decades after Coley's work a variety of natural and genetically modified non-pathogenic
bacterial species are being explored as potential antitumor agents, either to provide direct tumoricidal effects or to deliver
tumoricidal molecules. Live, attenuated or genetically modified non-pathogenic bacterial species are capable of multiplying
selectively in tumors and inhibiting their growth. Due to their selectivity for tumor tissues, these bacteria and their spores
also serve as ideal vectors for delivering therapeutic proteins to tumors. Bacterial toxins too have emerged as promising
cancer treatment strategy. The most potential and promising strategy is bacteria based gene-directed enzyme prodrug therapy.
Although it has shown successful results in vivo yet further investigation about the targeting mechanisms of the bacteria are required to make it a complete therapeutic approach
in cancer treatment. 相似文献
29.
30.
Jongrae Kim Min Kyung Kong Sang Yup Lee Pyung Cheon Lee 《World journal of microbiology & biotechnology》2010,26(12):2231-2239
The effects of three phosphoenolpyruvate (PEP)-dependent PTS carbon sources (glucose, mannose and maltose) and three non-PTS
carbon sources (glycerol, galactose, and lactose) on the formation of four carotenoids with diverse structures and on the
cell growth of the recombinant Escherichia coli were investigated. The biosynthetic pathways of four carotenoids, C30 diapolycopene, C30 diapotorulene, C40 lycopene, and C40 beta-carotene, were engineered in E. coli. The resulting E. coli cells were grown in a mineral medium supplemented with each of the six carbon sources. Among the six carbon sources, non-PTS
glycerol showed the highest performance in production of all four carotenoid structures, whereas PTS glucose showed the lowest
performance. Based on the conversion yield, carotenoid-producing capability, and the cell density, we found that there was
no close correlation between PTS and non-PTS transport mechanism and carotenoid formations in E. coli. 相似文献