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《Electromagnetic biology and medicine》2013,32(2):207-214
Protein phosphorylation is an extremely important and widely used mechanism of cellular regulation. Here, the effects of 50 Hz magnetic fields (MFs) on tyrosine phosphorylation were studied. A Chinese hamster lung (CHL) cell line was exposed to 50 Hz magnetic fields at two intensities (0.4 mT and 0.8 mT) for different exposure durations, and western blot analysis was used to measure the degree of tyrosine phosphorylation of cellular proteins. Results showed that both 0.4 mT and 0.8 mT 50 Hz magnetic fields could affect the protein tyrosine phosphorylation in cultured cells. Both intensities could affect the tyrosine phosphorylation of 38 and 97.4 kDa proteins. In addition, 0.4 mT could affect tyrosine phosphorylation of 61.7, 105, and 112 kDa proteins, and 0.8 mT affected the tyrosine phosphorylation of 79 and 150 kDa proteins. Moreover, all the tyrosine phosphorylation changes of these proteins were time-dependent. The findings from this study demonstrated that under these experimental conditions, there was evidence that protein tyrosine phosphorylation was a possible process for ELF-EMF producing bioeffects. 相似文献
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Extremely Low Frequency Magnetic Fields (ELF MF) has been considered as a “possible human carcinogen” by International Agency
for Research on Cancer (IARC) while credible mechanisms of its carcinogenicity remain unknown. In this study, a proteomics
approach was employed to investigate the changes of protein expression profile induced by ELF MF in human breast cancer cell
line MCF7, in order to determine ELF MF-responsive proteins. MCF7 cells were exposed to 50 Hz, 0.4 mT ELF MF for 24 h and
the changes of protein profile were examined using two dimensional electrophoresis. Up to 6 spots have been statistically
significantly altered (their expression levels were changed at least 5 fold up or down) compared with sham-exposed group.
19 ones were only detected in exposure group while 19 ones were missing. Three proteins were identified by LC-IT Tandem MS
as RNA binding protein regulatory subunit Proteasome subunit beta type 7 precursor and Translationally Controlled Tumor Protein.
Our finding showed that 50 Hz, 0.4 mT ELF MF alternates the protein profile of MCF7 cell and may affect many physiological
functions of normal cell and 2-DE coupled with MS is a promising approach to elucidating cellular effects of electromagnetic
fields. 相似文献
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Effects of ELF magnetic fields on protein expression profile of human breast cancer cell MCF7 总被引:3,自引:0,他引:3
LI Han ZENG Qunli WENG Yu LU Deqiang JIANG Huai & XU Zhengping . Bioelectromagnetics Laboratory Zhejiang University Hangzhou China . Research Center for Environmental Genomics Zhejiang University School of Medicine Hangzhou China 《中国科学:生命科学英文版》2005,48(5):506-514
A case-control study in 1979 on electrical wiring configurations and childhood leukemia had stimulated interest in the issue that extremely low frequency magnetic fields (ELF MF) may have harmful biologi-cal effects especially on the incidence of human can-cer[1]. Since then, a large number of studies have been conducted to follow up this important result[2]. The majority of these studies indicate a weak association between exposure to 50―60 Hz ELF MF and the in-cidence of cancer; however… 相似文献
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EXPOSURE TO 50 Hz MAGNETIC FIELDS DOES NOT INDUCE THE PHOSPHORYLATION OF SEK1/MKK4 IN CULTURED CELLS
《Electromagnetic biology and medicine》2013,32(1):97-102
In our previous studies, we found that 50 Hz magnetic fields (MFs) could induce the phosphorylation of stress-activated protein kinase (SAPK) and enhance its enzymatic activity. In order to clarify the relationship between MF exposure and the SAPK pathway clearly, we studied the effects of 50 Hz MF exposure on phosphorylation (activation) of SEK1/MKK4 (the upstream kinase of SAPK). A Chinese hamster lung (CHL) cell line was exposed to 50 Hz MFs at two intensities (0.4 and 0.8 mT) for different durations, and Western blot analysis was used to measure the degree of phosphorylation (activation), and nonphosphorylation (non-activation) of SEK1/MKK4 with corresponding antibodies. The results showed that the exposures at both intensities could not induce the phosphorylation of SEK1/MKK4. However, treatment with high osmotic pressure NaCl could induce the phosphorylation of SEK1/MKK4 in cultured cells. It is suggested that 50 Hz MFs may activate the SAPK through a kinase other than SEK1/MKK4. 相似文献
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Ewa Lindstrm Per Lindstrm Andr Berglund Erik Lundgren Kjell Hansson Mild 《Bioelectromagnetics》1995,16(1):41-47
Low-frequency magnetic fields (MF) can increase the cytosolic calcium concentration ([Ca2+]i) in lymphocytes in the same manner as a physiological stimulus such as antibodies directed towards the CD3 complex. In this study, MF with various frequencies and flux densities were used, while [Ca2+]i changes were recorded using microfluorometry with fura-2 as a probe. The applied sinusoidal MF induced oscillatory changes of [Ca2+], in the leukemic cell line Jurkat in a manner similar to that seen with stimulation by antibodies. The response at 0.15 mT was over a frequency range from 5 to 100 Hz, with a fairly broad peak having its maximum at 50 Hz. The result of testing increasing flux densities at 50 Hz was a threshold response with no effect below 0.04 mT and a plateau at 0.15 mT. On the basis of the characteristic calcium pattern resulting from an applied MF, we suggest that MF influence molecular events in regular signal transduction pathways of T cells. © 1995 Wiley-Liss, Inc. 相似文献
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Vascular endothelial cells (VEC) transduce mitogenic and chemoattractant signals in response to erythropoietin (Epo). An analysis of changes in gene expression in VEC would be helpful to understanding the molecular nature of mitogenic signals. An effective method for analysis of gene expression is through differential display. Using this approach, we obtained from Epo-treated human microvascular endothelial cells (HMVEC) a cDNA fragment with characteristics of the 3'end of mRNA. Using the cDNA fragment, we then isolated a full-length clone from a HMVEC cDNA library. The cDNA of interest encodes a protein consisting of 404 amino acids with a carboxy-terminal end sequence identical to glialblastoma cell differentiation factor-related protein (GBDR1). Northern blot analysis showed that GBDR1 mRNA was ubiquitously expressed in human tissues. In Southern blot analysis, GBDR1 cDNA identified a single gene on chromosome 9. Since analysis of the amino acid sequence revealed several putative phosphorylation sites for different protein kinases, the GBDR1 protein was expressed and purified from bacterial extracts and, as predicted, casein kinase II phosphorylated GBDR1 in vitro. Immunofluorescence and biochemical data revealed that the GBDR1 protein is not entirely localized in the cytosolic fraction, suggesting that it may interact with another protein(s). These findings demonstrate that GBDR1 is an intracellular signaling molecule that may play a role in the regulation of endothelial cell growth. 相似文献
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We have previously demonstrated that exposure of Chinese hamster lung (CHL) cells to 50 Hz magnetic fields (MFs) and/or 12-O-tetradecanoylphorbol-3-acetate (TPA)-inhibited gap junctional intercellular communication (GJIC). To explore and compare the mechanisms of GJIC inhibition induced by extremely low frequency (ELF) MF and TPA, the number and localization of connexin 43 (C x 43) were studied. The localization of C x 43 was determined with indirect immunofluorescence histochemical analysis and detected by confocal microscopy after exposing CHL cells to 50 Hz sinusoidal magnetic field at 0.8 mT for 24 h without or with TPA (5 ng/ml) for the last 1 h. The C x 43 levels in nuclei and in cytoplasm were examined by Western blotting analysis. The results showed that the cells exposed to MF and/or TPA displayed individual plaques at regions of intercellular contact, which were fewer than the normal cells in number, while the number of C x 43 in cytoplasm increased and congregated near the nuclei. Western blot analysis further demonstrated the quantity of changes in location of Cx43. These results suggest that reduction of C x 43 at regions of intercellular contact may be one of the mechanisms of GJIC inhibition induced by ELF MF. 相似文献
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An adult human liver cDNA library constructed in expression vector, bacteriophage lambda gt11, was screened with polyclonal antibody directed against human T4-binding globulin (TBG). TBG cDNA cloned in the present study was 944 nucleotides in length. It contained approximately 70% of the coding region and complete 3'-untranslated region. When the sequence was compared with that of TBG cDNA recently cloned by I. L. Flint, T. J. Bailey, T. A., Gustafson, B. E. Markham, and E. Morkin, the 3'-untranslated region of our cDNA was 231 nucleotides shorter than their cDNA. These results indicated that two TBG mRNAs with different length of 3'-untranslated regions may exist in human liver. Indeed, Northern blot analysis revealed that two TBG mRNAs differing in the length approximately 200 base pairs were present in normal human liver as well as in human hepatoma cell line (HepG2). It was demonstrated that this size difference was due to the length of 3'-untranslated region by hybridization with a probe specific to the longer 3'-end. Together with the sequence data, it was suggested that these two TBG mRNA species may be produced by alternative processing and polyadenylation at two different sites. 相似文献
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Wenjun Sun Qiu Tan Yongmiao Pan Yiti Fu Huilan Sun Huai Chiang 《Bioelectromagnetics》2010,31(7):566-572
Evidence from epidemiological and animal studies showed that exposure to extremely low frequency magnetic fields (ELF‐MF) could produce deleterious effects on reproduction. In order to investigate the possible mechanism of MF exposure on reproductive effects, first trimester human chorionic villi at 8–10 weeks' gestation were obtained, and trophoblasts were isolated, cultured, and exposed to a 50‐Hz MF for different durations. The human chorionic gonadotropin (hCG) and progesterone in the culture medium was measured by electrochemiluminescence immunoassay. The mRNA levels of apoptosis‐related genes bcl‐2, bax, caspase‐3, p53, and fas in trophoblasts were analyzed using real‐time RT‐PCR. The results showed that exposure of trophoblasts to MF at 0.2 mT for 72 h did not affect secretion of hCG and progesterone from these cells. There was also no significant change in secretion of these hormones when trophoblasts were exposed to a 0.4 mT MF for 48 h. However, MF significantly inhibited hCG and progesterone secretion of trophoblasts after exposure for 72 h at 0.4 mT. Results of apoptosis‐related gene expression analysis showed that, within 72 h of exposure at 0.4 mT, there was no significant difference between MF exposure and control on the expression pattern of each gene. Based on results of the present experiment, it is suggested that exposure to MF for a longer duration (72 h) could inhibit secretion of hCG and progesterone by human first trimester villous trophoblasts, however, the effect might not be related to trophoblast apoptosis. Bioelectromagnetics 31:566–572, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
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PS-2基因的克隆及其在肝癌中的表达 总被引:3,自引:0,他引:3
利用荧光差异显示技术比较了正常肝、肝硬化和肝癌组织 m RNA的表达 ,1 4个有差异的条带通过 Northern blot分析表明其中 9个为阳性 .令人感兴趣的是一个~ 5 0 0 bp的 c DNA片段 ,它在正常肝和肝硬化中低表达 ,在肝癌组织中高表达 .通过测序 ,发现该片段与 PS- 2 ( presenilin- 2 )基因有 94 %的同源性 .PS- 2基因的突变与早发性阿尔茨海默氏症有关 ,但在肝癌发生中的作用未明 .也许 PS- 2基因的上调涉及到肝癌发生的分子机理 相似文献
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Ruiz-Gómez MJ Ristori-Bogajo E Prieto-Barcia MI Martínez-Morillo M 《Electromagnetic biology and medicine》2010,29(4):154-164
In an attempt to determine whether magnetic field (MF) exposures might induce cellular alterations, S. cerevisiae yeast cells were exposed to static or sinusoidal 50?Hz homogeneous MF (0.35?mT, 1.4?mT, and 2.45?mT) for 1?h and 72?h. Unsynchronized cells grown exponentially while exposed to MF, containing cells in all stages of the mitotic cell cycle. MF was generated by a pair of Helmholtz coils (40?cm in diameter, coaxial, separated by 20?cm). Survival, cell cycle distribution, colony forming ability, and mutation frequency were assayed. No differences in the above-mentioned parameters were observed in MF exposed samples in relation to unexposed controls, suggesting that homogeneous MF at these intensities do not produce appreciable cellular alterations in this organism under typical in vitro growth conditions. 相似文献
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《Electromagnetic biology and medicine》2013,32(4):154-164
In an attempt to determine whether magnetic field (MF) exposures might induce cellular alterations, S. cerevisiae yeast cells were exposed to static or sinusoidal 50?Hz homogeneous MF (0.35?mT, 1.4?mT, and 2.45?mT) for 1?h and 72?h. Unsynchronized cells grown exponentially while exposed to MF, containing cells in all stages of the mitotic cell cycle. MF was generated by a pair of Helmholtz coils (40?cm in diameter, coaxial, separated by 20?cm). Survival, cell cycle distribution, colony forming ability, and mutation frequency were assayed. No differences in the above-mentioned parameters were observed in MF exposed samples in relation to unexposed controls, suggesting that homogeneous MF at these intensities do not produce appreciable cellular alterations in this organism under typical in vitro growth conditions. 相似文献