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Rashidieh B, Ansari AM, Behdani M, Darvishi B, Habibi-Anbouhi M. Extremely low frequency magnetic field enhances expression of a specific recombinant protein in bacterial host. Anal Biochem 2022; 652:114745. [DOI: 10.1016/j.ab.2022.114745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022]
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2
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Greenebaum B. Answers and Questions: Forty Years in Bioelectromagnetics. Bioelectromagnetics 2021; 43:47-63. [PMID: 34859455 DOI: 10.1002/bem.22381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 11/10/2022]
Abstract
The work began in 1972 when three young assistant professors used a slime mold to see if electromagnetic fields would affect it. The fields did, though the effects were small and hard to tease out of the noise. The cell cycle was lengthened and there were changes in respiration. So, the next question was "how and why?" Further changes were seen using these and then other bacterial and eukaryotic cells in respiration, in ATP, in the protein replication chain, and so forth. Changes occurred even in cell extracts that lacked an intact plasma membrane. Nerve cells showed changes in leakage of neurotransmitters and in neurite outgrowth from excised ganglia. Based on some experiments with nerve cells, I also did some computer calculations, modeling the internal electric and magnetic fields and current densities in simplified representations of bone fractures and also of spinal cords in vertebrae. More recently, I have collaborated on some theoretical models of what fields might be doing at the cellular and molecular level, particularly with reference to the radical model. With each piece of research, my collaborators and I generally found a small piece of information about fields and biological systems; and each answer raised another set of questions, which is the way of science. Though bioelectromagnetic scientists have learned much and can say much at greater depth about what happens when an organism is exposed to a field, the fundamental question still remains: What exactly is going on here? © 2021 Bioelectromagnetics Society.
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Affiliation(s)
- Ben Greenebaum
- Physics Department, University of Wisconsin-Parkside, Kenosha, Wisconsin
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Li J, Cai S, Zhou B, Meng X, Guo Q, Yang X, Huang J, Wang K. Photocaged FRET nanoflares for intracellular microRNA imaging. Chem Commun (Camb) 2020; 56:6126-6129. [DOI: 10.1039/d0cc02395g] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Herein, we developed photocaged FRET nanoflares for spatiotemporal microRNA imaging in living cells. In other words, the probes will not work until they are exposed to UV light.
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Affiliation(s)
- Jing Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Shijun Cai
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Bing Zhou
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Xiangxian Meng
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Qiuping Guo
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Jin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- College of Biology
- Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province
- Hunan University
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Sun L, Li X, Ma H, He R, Donkor PO. Global gene expression changes reflecting pleiotropic effects of Irpex lacteus
induced by low-intensity electromagnetic field. Bioelectromagnetics 2019; 40:104-117. [DOI: 10.1002/bem.22171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 01/14/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Ling Sun
- School of Food and Biological Engineering; Jiangsu University; Zhenjiang Jiangsu China
| | - Xinyi Li
- School of Food and Biological Engineering; Jiangsu University; Zhenjiang Jiangsu China
| | - Haile Ma
- School of Food and Biological Engineering; Jiangsu University; Zhenjiang Jiangsu China
| | - Ronghai He
- School of Food and Biological Engineering; Jiangsu University; Zhenjiang Jiangsu China
| | - Prince O. Donkor
- School of Food and Biological Engineering; Jiangsu University; Zhenjiang Jiangsu China
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Ben Mouhoub R, Mansouri A, Aliliche K, Beghalem H, Landoulsi A, El May A. Unraveling the expression of genes involved in the biosynthesis pathway of cardiolipin and phosphatidylethanolamine in Salmonella Hadar grown under static magnetic field 200 mT. Microb Pathog 2017; 111:414-421. [PMID: 28923603 DOI: 10.1016/j.micpath.2017.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/14/2017] [Accepted: 09/14/2017] [Indexed: 01/07/2023]
Abstract
We aimed in this work to evaluate the effect of static magnetic field 200 mT (SMF) on the expression of genes involved in the biosynthetic pathway of cardiolipin: g3pd, plsB, cdsA, pgsA, pgpA, cls and phosphatidylethanolamine: pssA and psd in Salmonella enterica subsp enterica serovar Hadar. Bacteria were exposed to a SMF during 3, 6 and 9 h. RNA extraction was followed by Reverse Transcriptase Polymerase Chain Reaction RT-PCR. The relative quantification of mRNA expression levels using 16S rRNA doesn't change during the time exposure. RT-PCR was done for two exposure experiments. The gene expression using RT-PCR present no significant difference in case of plsB, cdsA, pgpA, pgsA and psd genes during the different exposure times. However, a significant increase was observed in the expression of g3pd and pssA genes after 6 h and for cls gene after 3 h of exposure, but any variation was notified after 9 h of exposure. So we can conclude from this study that cls, g3pd and pssA genes are required in the adaptation of Salmonella Hadar to SMF.
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Affiliation(s)
- Ramla Ben Mouhoub
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia.
| | - Ahlem Mansouri
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
| | - Khadidja Aliliche
- Laboratory of Genetics, Faculty of Science of Bizerte, Zarzouna 7021, Tunisia
| | - Hamida Beghalem
- Laboratory of Genetics, Faculty of Science of Bizerte, Zarzouna 7021, Tunisia
| | - Ahmed Landoulsi
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
| | - Alya El May
- Biochemistry and Molecular Biology, Code UR13ES34 Research Unit, Faculty of Sciences of Bizerte, Zarzouna 7021, Carthage University, Tunisia
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Zhang J, Xu C, Wan Y, Gao M. Effects of extremely low frequency magnetic field on production of mannatide byα-hemolytic Streptococcus. Bioelectromagnetics 2016; 37:331-7. [DOI: 10.1002/bem.21984] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 05/12/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Jialan Zhang
- College of Animal Science; Yangtze University; Jingzhou Hubei China
| | - Cui Xu
- College of Life Science; Yangtze University; Jingzhou Hubei China
| | - Yunlei Wan
- College of Life Science; Yangtze University; Jingzhou Hubei China
| | - Mengxiang Gao
- College of Life Science; Yangtze University; Jingzhou Hubei China
- Jingchu Food Research and Development Center; Yangtze University; Jingzhou Hubei China
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Snoussi S, El May A, Coquet L, Chan P, Jouenne T, Dé E, Landoulsi A. Unraveling the effects of static magnetic field stress on cytosolic proteins of Salmonella by using a proteomic approach. Can J Microbiol 2015; 62:338-48. [PMID: 26928316 DOI: 10.1139/cjm-2015-0532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study investigated the adaptation of Salmonella enterica subsp. enterica serovar Hadar to static magnetic field (SMF) exposure (200 mT, 9 h). The proteomic analysis provides an overview of potentially important cytosolic proteins that Salmonella needs to regulate to survive and adapt to magnetic stress. Via 2-dimensional electrophoresis and liquid chromatography tandem mass spectrometry, we compared cytosolic proteomes before and after exposure to magnetic field. A total of 35 proteins displaying more than a 2-fold change were differentially expressed in exposed cells, among which 25 were upregulated and 10 were downregulated. These proteins can be classified mainly into 6 categories: (i) proteins involved in metabolic pathways of carbohydrates, (ii) chaperones and proteins produced in response to oxidative stress, (iii) proteins involved in energy homeostasis, (iv) elongation factors (EF-Tu and EF-Ts), (v) proteins involved in motility, and (vi) proteins involved in molecules transport. Many of the presented observations could be explained, while some represent still-unknown mechanisms. In addition, this study reveals 5 hypothetical proteins. It seems that the stress response to SMF (200 mT) is essentially set up to avoid oxidative damages, with the overexpression of proteins directly involved in oxidative stress response and metabolic switches to counteract oxidative stress. Interestingly, several proteins induced under SMF exposure are found to overlap with those induced by other stresses, such as heat shock and starvation.
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Affiliation(s)
- Sarra Snoussi
- a Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Bizerte, Tunisie.,b UMR 6270 CNRS, Faculté des sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France
| | - Alya El May
- a Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Bizerte, Tunisie
| | - Laurent Coquet
- b UMR 6270 CNRS, Faculté des sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France
| | - Philippe Chan
- b UMR 6270 CNRS, Faculté des sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France
| | - Thierry Jouenne
- b UMR 6270 CNRS, Faculté des sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France
| | - Emmanuelle Dé
- b UMR 6270 CNRS, Faculté des sciences, Université de Rouen, 76821 Mont Saint Aignan Cedex, France
| | - Ahmed Landoulsi
- a Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Bizerte, Tunisie
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Tessaro LWE, Murugan NJ, Persinger MA. Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields. Microbiol Res 2015; 172:26-33. [PMID: 25721476 DOI: 10.1016/j.micres.2014.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 12/15/2014] [Accepted: 12/19/2014] [Indexed: 10/24/2022]
Abstract
Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species.
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Affiliation(s)
- Lucas W E Tessaro
- Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6; Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6.
| | - Nirosha J Murugan
- Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6; Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
| | - Michael A Persinger
- Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario, Canada P3E 2C6; Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6.
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Esmekaya MA, Acar SI, Kıran F, Canseven AG, Osmanagaoglu O, Seyhan N. Effects of ELF magnetic field in combination with Iron(III) chloride (FeCl3) on cellular growth and surface morphology of Escherichia coli (E. coli). Appl Biochem Biotechnol 2013; 169:2341-9. [PMID: 23446980 DOI: 10.1007/s12010-013-0146-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 02/18/2013] [Indexed: 11/30/2022]
Abstract
This study investigated the effects of extremely low frequency (ELF) magnetic field with/without iron(III) chloride (FeCl3) on bacterial growth and morphology. The ELF exposures were carried out using a pair of Helmholtz coil-based ELF exposure system which was designed to generate 50 Hz sinusoidal magnetic field. The field was approximately uniform throughout the axis of the coil pair. The samples which were treated or non-treated with different concentrations FeCl3 were exposed to 50 Hz, 2 millitesla (mT) magnetic field for 24 h. ELF effect on viability was assessed in terms of viable colony counts (in colony-forming unit per milliliter) with the standard plate count technique. Scanning electron microscopy was used to investigate the magnetic field effect on surface morphology of Escherichia coli. No significant results were seen in terms of cell viability between ELF and sham-exposed bacterial strains. Similarly, FeCl3 treatment did not change cell viability of E. coli samples. However, we observed some morphological changes on E. coli cell surfaces. Pore formations and membrane destruction were seen on the surface of 24 h ELF field-exposed cells. We concluded that ELF magnetic field exposure at 2 mT does not affect cell viability; however, it may affect bacterial surface morphology.
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Affiliation(s)
- Meric A Esmekaya
- Department of Biophysics, Faculty of Medicine & Gazi Non-ionizing Radiation Protection (GNRP) Center, Gazi University, Ankara, Turkey.
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Huwiler SG, Beyer C, Fröhlich J, Hennecke H, Egli T, Schürmann D, Rehrauer H, Fischer HM. Genome-wide transcription analysis of Escherichia coli in response to extremely low-frequency magnetic fields. Bioelectromagnetics 2012; 33:488-96. [DOI: 10.1002/bem.21709] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 01/11/2012] [Indexed: 11/09/2022]
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Snoussi S, May AE, Coquet L, Chan P, Jouenne T, Landoulsi A, Dé E. Adaptation of Salmonella enterica Hadar under static magnetic field: effects on outer membrane protein pattern. Proteome Sci 2012; 10:6. [PMID: 22304719 PMCID: PMC3292939 DOI: 10.1186/1477-5956-10-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 02/03/2012] [Indexed: 12/29/2022] Open
Abstract
Background Salmonella enterica serovar Hadar (S. Hadar) is a highly prevalent foodborne pathogen and therefore a major cause of human gastroenteritis worldwide. Outer membrane proteins whose production is often regulated by environmental conditions also play important roles in the adaptability of bacterial pathogens to various environments. Results The present study investigated the adaptation of S. Hadar under the effect of acute static magnetic field exposure (200 mT, 9 h) and the impact on the outer membrane protein pattern. Via two-dimensional electrophoresis (2-DE) and LC-MS/MS spectrometry, we compared the proteome of enriched-outer membrane fraction before and after exposure to a magnetic field. A total of 11 proteins, displaying more than a two-fold change, were differentially expressed in exposed cells, among which 7 were up-regulated and 4 down-regulated. These proteins were involved in the integrity of cell envelope (TolB, Pal), in the response to oxidative stress (OmpW, dihydrolipoamide dehydrogenase, UspF), in the oxidative stress status (bacterioferritin), in virulence (OmpX, Yfgl) or in motility (FlgE and UspF). Complementary experiments associated the down-regulation of FlgE and UspF with an alteration of swarming, a flagella-driven motility, under SMF. Furthermore, the antibiotic disc diffusion method confirmed a decrease of gentamicin susceptibility in exposed cells. This decrease could be partly associated with the up-regulation of TolC, outer membrane component of an efflux pump. OmpA, a multifunctional protein, was up-regulated. Conclusions SMF (200 mT) seems to maintain the cell envelope integrity and to submit the exposed cells to an oxidative stress. Some alterations suggest an increase of the ability of exposed cells to form biofilms.
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Affiliation(s)
- Sarra Snoussi
- Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Université de Carthage, Zarzouna, Bizerte, Tunisie.
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Potenza L, Martinelli C, Polidori E, Zeppa S, Calcabrini C, Stocchi L, Sestili P, Stocchi V. Effects of a 300 mT static magnetic field on human umbilical vein endothelial cells. Bioelectromagnetics 2011; 31:630-9. [PMID: 20623760 DOI: 10.1002/bem.20591] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This study describes the effects of a static magnetic field (SMF) on cell growth and DNA integrity of human umbilical vein endothelial cells (HUVECs). Fast halo assay was used to investigate nuclear damage; quantitative polymerase chain reaction (QPCR), standard PCR, and real-time PCR were used to evaluate mitochondrial DNA integrity, content, and gene expression. HUVECs were continually exposed to a 300 mT SMF for 4, 24, 48, and 72 h. Compared to control samples (unexposed cultures) the SMF-exposed cells did not show a statistically significant change in their viability. Conversely, the static field was shown to be significant after 4 h of exposure, inducing damage on both the nuclear and mitochondrial levels, reducing mitochondrial content and increasing reactive oxygen species. Twenty-four hours of exposure increased mitochondrial DNA content as well as expression of one of the main genes related to mitochondrial biogenesis. No significant differences between exposed and sham cultures were found after 48 and 72 h of exposure. The results suggest that a 300 mT SMF does not cause permanent DNA damage in HUVECs and stimulates a transient mitochondrial biogenesis.
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Affiliation(s)
- Lucia Potenza
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino "Carlo Bo", Urbino, Italy.
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El May A, Snoussi S, Ben Miloud N, Maatouk I, Abdelmelek H, Ben Aïssa R, Landoulsi A. Effects of Static Magnetic Field on Cell Growth, Viability, and Differential Gene Expression in Salmonella. Foodborne Pathog Dis 2009; 6:547-52. [DOI: 10.1089/fpd.2008.0244] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Alya El May
- Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Tunisia
| | - Sarra Snoussi
- Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Tunisia
| | - Najla Ben Miloud
- Laboratoire de Microbiologie et Biologie Moléculaire, Centre National des Sciences et Technologies Nucléaires, Sidi Thabet, Tunisia
| | - Imed Maatouk
- Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Tunisia
| | - Hafedh Abdelmelek
- Laboratoire de Physiologie Intégrée, Faculté des Sciences de Bizerte, Zarzouna, Tunisia
| | - Ridha Ben Aïssa
- Laboratoire de Contrôle des Eaux et Denrées Alimentaires, Centre National des Salmonella, Shigella, et Vibrio, Institut Pasteur de Tunis, Tunisia
| | - Ahmed Landoulsi
- Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Tunisia
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Schwenzer NF, Bantleon R, Maurer B, Kehlbach R, Schraml C, Claussen CD, Rodegerdts E. Do static or time-varying magnetic fields in magnetic resonance imaging (3.0 T) alter protein-gene expression?-A study on human embryonic lung fibroblasts. J Magn Reson Imaging 2008; 26:1210-5. [PMID: 17969170 DOI: 10.1002/jmri.21145] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate the influence of magnetic resonance imaging (MRI) on gene expression in embryonic human lung fibroblasts (Hel 299). MATERIALS AND METHODS The cells were exposed to the static magnetic field and to a turbo spin-echo sequence of an MR scanner at 3.0 Tesla. An MR group (exposed) and a control group (sham-exposed) were set up using a special MR-compatible incubation system. The exposure time was two hours. Gene expression profiles were studied using a complementary deoxyribonucleic acid (cDNA) microarray containing 498 known genes involved in transcription, intracellular transport, structure/junction/adhesion or extracellular matrix, signaling, host defense, energetics, metabolism, cell shape, and death. RESULTS No changes in gene expression were found in either group (exposed or sham-exposed cells) at the end of a two-hour exposure for any of the 498 tested protein genes. CONCLUSION The results suggest that MRI has no influence on protein-gene expression in eugenic human lung cells.
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Affiliation(s)
- Nina F Schwenzer
- Department of Diagnostic Radiology, Eberhard-Karls University, Tübingen, Germany.
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Abstract
AbstractThe ability to respond to magnetic fields is ubiquitous among the five kingdoms of organisms. Apart from the mechanisms that are at work in bacterial magnetotaxis, none of the innumerable magnetobiological effects are as yet completely understood in terms of their underlying physical principles. Physical theories on magnetoreception, which draw on classical electrodynamics as well as on quantum electrodynamics, have greatly advanced during the past twenty years, and provide a basis for biological experimentation. This review places major emphasis on theories, and magnetobiological effects that occur in response to weak and moderate magnetic fields, and that are not related to magnetotaxis and magnetosomes. While knowledge relating to bacterial magnetotaxis has advanced considerably during the past 27 years, the biology of other magnetic effects has remained largely on a phenomenological level, a fact that is partly due to a lack of model organisms and model responses; and in great part also to the circumstance that the biological community at large takes little notice of the field, and in particular of the available physical theories. We review the known magnetobiological effects for bacteria, protists and fungi, and try to show how the variegated empirical material could be approached in the framework of the available physical models.
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Williams PA, Ingebretsen RJ, Dawson RJ. 14.6 mT ELF magnetic field exposure yields no DNA breaks in model systemSalmonella, but provides evidence of heat stress protection. Bioelectromagnetics 2006; 27:445-50. [PMID: 16732588 DOI: 10.1002/bem.20210] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, we demonstrate that common extremely low frequency magnetic field (MF) exposure does not cause DNA breaks in this Salmonella test system. The data does, however, provide evidence that MF exposure induces protection from heat stress. Bacterial cultures were exposed to MF (14.6 mT 60 Hz field, cycled 5 min on, 10 min off for 4 h) and a temperature-matched control. Double- and single-stranded DNA breaks were assayed using a recombination event counter. After MF or control exposure they were grown on indicator plates from which recombination events can be quantified and the frequency of DNA strand breaks deduced. The effect of MF was also monitored using a recombination-deficient mutant (recA). The results showed no significant increase in recombination events and strand breaks due to MF. Evidence of heat stress protection was determined using a cell viability assay that compared the survival rates of MF exposed and control cells after the administration of a 10 min 53 degrees C heat stress. The control cells exhibited nine times more cell mortality than the MF exposed cells. This Salmonella system provides many mutants and genetic tools for further investigation of this phenomenon.
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Affiliation(s)
- Parley A Williams
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
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Alvarez DC, Pérez VH, Justo OR, Alegre RM. Effect of the extremely low frequency magnetic field on nisin production by Lactococcus lactis subsp. lactis using cheese whey permeate. Process Biochem 2006. [DOI: 10.1016/j.procbio.2006.04.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Laubitz D, Jankowska A, Sikora A, Woliński J, Zabielski R, Grzesiuk E. Gut myoelectrical activity induces heat shock response in Escherichia coli and Caco-2 cells. Exp Physiol 2006; 91:867-75. [PMID: 16728456 DOI: 10.1113/expphysiol.2006.033365] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The heat shock response is associated with the intracellular expression of a number of highly conserved heat shock proteins (Hsps). According to their molecular size, Hsps have been divided into several groups, which are strongly conserved and show high homology between the species, e.g., Hsp70, MW 70 kDa (Lindquist & Craig, 1998; Morimoto, 1998; Jolly & Morimoto, 2000; Zylicz et al. 2001). In all organisms the Hsp expression under stress conditions is regulated at transcriptional level, e.g., in humans by the heat shock transcription factor Hsf1 (Morimoto, 1998; Wu, 1995), while in Escherichia coli by replacement of the sigma factor sigma(70) in RNA polymerase by the sigma factor sigma(32) (Gross, 1987). The Hsps allow cell survival under stress conditions by renaturating of denaturated proteins, protecting of stress-labile proteins, preventing protein aggregation (chaperone functions), and by degradation of damaged proteins (protease activities) (Lindquist & Craig, 1988; Morimoto, 1998; Jolly & Morimoto, 2000). They have also many housekeeping functions under non-stressful conditions during the cell cycle, growth, development, and differentiation (Morimoto, 1998). Among a number of plausible inducing factors already studied, extremely low artificial electromagnetic fields have been shown to induce stress response in various cells, such as expression of sigma(32) mRNA (Cairo et al. 1998) and induction of DnaJ and DnaK proteins in Eschericha coli (Chow & Tung, 2000); expression of hsp-16 gene in Caenorhabditis elegans (Miyakawa et al., 2001); induction of heat shock transcription factor Hsf1 and Hsp70, Hsp90 and Hsp27 in human cells (Lin et al. 1997; Lin et al. 1998; Goodman & Blank, 1998; Pipkin et al. 1999). Nevertheless, the role of endogenous electromagnetic fields, i.e., generated by electrically active cells within a body remains controversial. Heat shock proteins (Hsps) protect cells against various environmental and endogenous stressors. Cytoprotection caused by Hsps involves tolerance induced by one agent against other, more severe agents. We have found that exposure of prokaryotic (Escherichia coli) and eukaryotic (Caco-2) cells to an electrical field (EF) connected with a myoelectrical migrating complex (MMC) generated by the small intestine smooth muscle induces the heat shock response. Using Western blot analysis, we have detected an elevated level of sigma factor 32 in E. coli cells exposed to MMC-related EF, and confocal microscopy indicated an increased level of the inducible form of Hsp70 protein in EF-stimulated Caco-2 cells. Additionally, we have found that this induced level of Hsp70 protected the Caco-2 cells against apoptosis caused by camptothecin. Our observations suggest that the myoelectrical activity of the gut may induce heat shock mechanisms in the cells of gut epithelium as well as in gastrointestinal micro-organisms.
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Affiliation(s)
- Daniel Laubitz
- The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 02-106 Warsaw, Poland
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Del Re B, Bersani F, Mesirca P, Giorgi G. Synthesis of DnaK and GroEL in Escherichia coli cells exposed to different magnetic field signals. Bioelectrochemistry 2006; 69:99-103. [PMID: 16464648 DOI: 10.1016/j.bioelechem.2005.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 11/11/2005] [Accepted: 11/21/2005] [Indexed: 11/16/2022]
Abstract
The effects of extremely low frequency magnetic field (ELF-MF)(1 mT, 50 Hz) on the heat shock protein (HSP) synthesis in Escherichia coli were investigated. Two magnetic field signals were studied: sinusoidal (SMF) and pulsed square wave (PMF). It was found that bacteria exposed to SMF showed a significantly higher level of DnaK and GroEL proteins as compared to sham-exposed bacteria as revealed by Western blot, whereas a lower level was observed after PMF exposure. Similar results were obtained when bacterial cells were exposed to heat shock (HS) after ELF-MF exposure: again SMF and PMF resulted in an increase and in a reduction of HSP amount in comparison with sham control, respectively. In conclusion, the MF influences the synthesis of HSPs in E. coli in a way that critically depends on the signal characteristics.
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Affiliation(s)
- Brunella Del Re
- Department of Evolutionary Experimental Biology, University of Bologna, via Selmi 3, 40126 Bologna, Italy
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Abdelmelek H, Molnar A, Servais S, Cottet-Emard JM, Pequignot JM, Favier R, Sakly M. Skeletal muscle HSP72 and norepinephrine response to static magnetic field in rat. J Neural Transm (Vienna) 2005; 113:821-7. [PMID: 16252069 DOI: 10.1007/s00702-005-0364-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 08/28/2005] [Indexed: 10/25/2022]
Abstract
The present work was undertaken in order to investigate the noradrenergic system and skeletal muscle heat shock protein 72 (HSP72) response to static magnetic field (MF) in male rats. At thermoneutrality (25 degrees C), the exposition of rats 1 hour/day for 5 consecutive days to MF of 128 mT (m tesla) induced an increase in norepinephrine content in gastrocnemius muscle (+25%, p < 0.05) but had no effect at 67 mT (+1%, p > 0.05), indicating a stimulatory effect of sub-acute MF exposure on the noradrenergic system activity. Moreover, exposed rats to MF displayed a non-significant increase of HSP72 levels in gastrocnemius muscles (+29%, p > 0.05). The results indicate that noradrenergic systems in rat's gastrocnemius muscles are affected by MF exposure. Interestingly, sub-acute exposure insufficiency increased HSP72 levels in gastrocnemius muscles.
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Affiliation(s)
- H Abdelmelek
- Laboratoire de Physiologie Animale, Faculté des Sciences de Bizerte, Jarzouna, Tunisia.
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Potenza L, Ubaldi L, De Sanctis R, De Bellis R, Cucchiarini L, Dachà M. Effects of a static magnetic field on cell growth and gene expression in Escherichia coli. Mutat Res 2004; 561:53-62. [PMID: 15238230 DOI: 10.1016/j.mrgentox.2004.03.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Revised: 03/08/2004] [Accepted: 03/19/2004] [Indexed: 10/26/2022]
Abstract
Escherichia coli cultures exposed to a 300mT static magnetic field (SMF) were studied in order to analyse possible induced changes in cellular growth and gene expression. Biomass was evaluated by visible-light spectrometry and gene expression analyses were carried out by use of RNA arbitrarily primed PCR. The bacterial strain XL-1Blue, cultivated in traditional and modified Luria-Bertani medium, was exposed to SMF generated by permanent neodymium magnetic disks. The results show alterations induced by SMF in terms of increased cell proliferation and changes in gene expression compared with control groups. Three cDNAs were found to be expressed only in the exposed cells, whereas one cDNA was more expressed in the controls. One clone, expressed only in the exposed cells, corresponds to a putative transposase. This is of particular interest in that it suggests that exposure to a magnetic field may stimulate transposition activity.
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Affiliation(s)
- Lucia Potenza
- Giorgio Fornaini Institute of Biological Chemistry, University of Urbino Carlo Bo, 61029 Urbino, PU, Italy.
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Nakasono S, Laramee C, Saiki H, McLeod KJ. Effect of power-frequency magnetic fields on genome-scale gene expression in Saccharomyces cerevisiae. Radiat Res 2003; 160:25-37. [PMID: 12816520 DOI: 10.1667/rr3006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
To estimate the effect of 50 Hz magnetic-field exposure on genome-wide gene expression, the yeast Saccharomyces cerevisiae was used as a model for eukaryotes. 2D PAGE (about 1,000 spots) for protein and cDNA microarray (about 5,900 genes) analysis for mRNA were performed. The cells were exposed to 50 Hz vertical magnetic fields at 10, 150 or 300 mT r.m.s. for 24 h. As positive controls, the cells were exposed to aerobic conditions, heat (40 degrees C) or minimal medium. The 2D PAGE and microarray analyses for the positive controls showed high-confidence differential expression of many genes including those for known or unknown proteins and mRNAs. For magnetic-field exposure, no high-confidence changes in expression were observed for proteins or genes that were related to heat-shock response, DNA repair, respiration, protein synthesis and the cell cycle. Principal component analysis showed no statistically significant difference in principal components, with only insignificant differences between the magnetic-field intensities studied. In contrast, the principal components for the positive controls were significantly different. The results indicate that a 50 Hz magnetic field below 300 mT did not act as a general stress factor like heat shock or DNA damage, as had been reported previously by others. This study failed to find a plausible differential gene expression that would point to a possible mechanism of an effect of magnetic fields. The findings provide no evidence that the magnetic-field exposure alters the fundamental mechanism of translation and transcription in eukaryotic cells.
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Affiliation(s)
- Satoshi Nakasono
- Bio-Science Department, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-City, Chiba 270-1194, Japan.
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Di Carlo A, White N, Guo F, Garrett P, Litovitz T. Chronic electromagnetic field exposure decreases HSP70 levels and lowers cytoprotection. J Cell Biochem 2002. [DOI: 10.1002/jcb.10036] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Chapter 25 Electric fields and currents of the small intestine and their effects on Escherichia coli. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1877-1823(09)70141-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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25
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Wójcik-Sikora A, Laubitz D, Pierzynowski SG, Grzesiuk E. Exposure of Escherichia coli to intestinal myoelectrical activity-related electric field induces resistance against subsequent UV(254 nm) (UVC) irradiation. Mutat Res 2001; 496:97-104. [PMID: 11551485 DOI: 10.1016/s1383-5718(01)00212-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Survival of Escherichia coli K-12 AB1157 irradiated with UVC (UV(254 nm)) was enhanced after pre-treatment with a low-tension electric field (EF). The EF used was identical to the electrical field generated by the small intestine (myoelectrical migrating complex--MMC), registered in a healthy calf and transmitted into the memory of an EF generator. The EF emitted by the generator was transmitted via electrodes placed in shaken bacterial cultures. The protective effects of the EF on the E. coli survival after exposure to UV were: (i) observed only for the dnaJ(+)dnaK(+) strain, and not for the DeltadnaJdnaK heat shock mutant; (ii) strictly dependent on the temperature at which the bacteria were grown; (iii) most obvious when the bacteria were incubated at 37 degrees C. Moreover, the MMC-related EF and a higher temperature (40 degrees C) show a similar protective effect against UV-irradiation. The results point to the involvement of the heat shock response in the low-tension EF-induced protection of bacterial cells against UVC-irradiation. Additionally, treatment with the MMC-related EF affects total protein contents and their pattern in E. coli cells. The EF-treatment did not show any influence on the level of the argE3(ochre) --> Arg(+) reversions.
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Affiliation(s)
- A Wójcik-Sikora
- Department of Molecular Biology, Institute of Biochemistry and Biophysics, PAS, Pawinskiego 5A, 02-106, Warsaw, Poland
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Grzesiuk E, Laubitz D, Wójcik-Sikora A, Zabielski R, Pierzynowski SG. Influence of intestinal myoelectrical activity on the growth of Escherichia coli. Bioelectromagnetics 2001; 22:449-55. [PMID: 11536286 DOI: 10.1002/bem.72] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Intestinal bacteria, particularly those adhering to intestinal epithelial cells, are exposed to electric fields and currents generated by the muscular activity of the small intestine. This activity displays a regular pattern known as the myoelectrical migrating complex (MMC). In order to explore the possibility that these endogenous electric fields could affect bacterial growth, a digitised duodenal signal obtained via serosal electrodes from a healthy calf was recorded and then applied via platinum electrodes to Escherichia coli cultures. The culture tubes were placed within a Faraday shield, incubated at 37 degrees C with shaking, and stimulated by the electric current for 5 or 8 h. The growth of E. coli stimulated by the electric current was significantly altered compared to those of non-stimulated controls: after a period of intensive growth, inhibition of cell division was observed. This was not the case when the bacteria with lon mutation were used. Moreover, synchronic bacterial culture could not be achieved in the presence of the MMC-related electric field. These results suggest that the myoelectrical activity of the duodenum, through action on cell membrane, can affect cell division of intestinal bacteria.
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Affiliation(s)
- E Grzesiuk
- Department of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
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Wu RY, Chiang H, Hu GL, Zeng QL, Bao JL. The effect of 50 Hz magnetic field on GCSmRNA expression in lymphoma B cell by mRNA differential display. J Cell Biochem 2000; 79:460-70. [PMID: 10972983 DOI: 10.1002/1097-4644(20001201)79:3<460::aid-jcb110>3.0.co;2-t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Magnetic fields (MFs) of various characteristics can lead to plethora effects in biological system. From a molecular point of view, we hypothesized that there must be a fundamental difference in gene expression between the MF exposed and the unexposed cell. To identify the classes of genes that are regulated, 0.8 mT 50 Hz MF-induced changes in gene expression were examined in a Daudi cell culture using differential display and reverse transcriptase-polymerase chain reaction. A candidate cDNA (signatured as MF-CB) that was observed in the sham-exposed but not in MF-exposed cultures was recovered and reamplified. After verification by Northern blot, the cDNA was cloned and sequenced. It was found that 254-base pair of 5'-end MF-CB cDNA clone was identical to gcs in open reading frame (ORF) range. Based on the preliminarily sequence, the prolonged length of 5'-end MF-CB cDNA was obtained by PCR amplification and its sequence analysis showed the same results as its original fragment. In order to further determine whether MF-CB cDNA is from gcs, two Northern blots were probed with gcs and MF-CB cDNA, respectively, and the data revealed signals of the same size and expression pattern on the two probe filters, which demonstrated that MF-CB is an EST (expression sequence tag) of gcs. gcs is a gene, identified recently (GenBank accession number D89866), encoding ceramide glucosyltransferase (GCS), which has been implicated as a causal element in human cell growth and differentiation. In an additional experiment, time-dependent changes in the transcription of gcs induced by 0.8 mT MF were observed by Northern blot with a sharp and reproducible inhibition effect after 20 min exposure and a reduction after 20-24 h exposure. The study demonstrates for the first time that 50 Hz MF can lead to changes in gcs transcription, which provides a new clue to elucidate the mechanism by which MF influence cell growth and differentiation.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Blotting, Northern
- Burkitt Lymphoma/genetics
- Burkitt Lymphoma/pathology
- Cloning, Molecular
- DNA, Complementary/genetics
- Enzyme Induction/radiation effects
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic/radiation effects
- Glucosyltransferases/biosynthesis
- Glucosyltransferases/genetics
- Humans
- Magnetics
- Molecular Sequence Data
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Polymerase Chain Reaction
- RNA, Messenger/biosynthesis
- RNA, Neoplasm/biosynthesis
- Sequence Homology, Nucleic Acid
- Subtraction Technique
- Transcription, Genetic/radiation effects
- Tumor Cells, Cultured/metabolism
- Tumor Cells, Cultured/radiation effects
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Affiliation(s)
- R Y Wu
- Microwave Lab, Medical College, Zhejiang University, Hangzhou 310031, P.R. China
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Abstract
Escherichia coli K12 was used as a model system to determine whether ELF magnetic fields (MFs) are a general stress factor. The cells were exposed to ELF MFs (5-100 Hz) at a maximum intensity of 14 mT r. m.s. for circularly polarized MFs and 10 mT r.m.s. for vertically polarized MFs. The response of the cells to the MFs was estimated from the change in protein synthesis by using 2D PAGE. Approximately 1,000 proteins were separated on the 2D gels. The stress-responsive proteins such as CH10, DNAK, CH60, RECA, USPA, K6P1 and SODM were identified from the SWISS-2DPAGE database on the 2D gels. These proteins respond to most stress factors, including temperature change, chemical compounds, heavy metals, and nutrients. When the bacterial cells were exposed to each MF at 5-100 Hz under aerobic conditions (6.5 h) or at 50 Hz under anaerobic conditions (16 h) at the maximum intensity (7.8 to 14 mT r.m.s.), no reproducible changes were observed in the 2D gels. Changes in protein synthesis were detected by 2D PAGE with exposure to heat shock (50 degrees C for 30 min) or under anaerobic conditions (no bubbling for 16 h). Increases in the levels of synthesis of the stress proteins were observed in heat-shocked cells (CH60, CH10, HTPG, DNAK, HSLV, IBPA and some unidentified proteins) and in cells grown under anaerobic conditions (DNAK, PFLB, RECA, USPA and many unidentified proteins). These results suggest that 2D PAGE is sufficient to detect cell responses to environmental stress. The high-intensity ELF MFs (14 mT at power frequency) did not act as a general stress factor.
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Affiliation(s)
- S Nakasono
- Bio-Science Department, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-City, Chiba 270-1194, Japan
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Abstract
In contrast to the common impression that exposure to a magnetic field of low frequency causes mutations to organisms, we have demonstrated that a magnetic field can actually enhance the efficiency of DNA repair. Using Escherichia coli strain XL-1 Blue as the host and plasmid pUC8 that had been mutagenized by hydroxylamine as the vector for assessment, we found that bacterial transformants that had been exposed to a magnetic field of 50 Hz gave lower percentages of white colonies as compared to transformants that had not been exposed to the magnetic field. This result was indicative that the efficiency of DNA repair had been improved. The improvement was found to be mediated by the induced overproduction of heat shock proteins DnaK/J (Hsp70/40).
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Affiliation(s)
- K Chow
- Department of Biochemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, Kowloon, PR China.
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Chow KC, Tung WL. Magnetic field exposure stimulates transposition through the induction of DnaK/J synthesis. Biochem Biophys Res Commun 2000; 270:745-8. [PMID: 10772895 DOI: 10.1006/bbrc.2000.2496] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Like some naturally occurring environmental stress factors such as heat shock and UV irradiation, magnetic field exposure is also stimulatory to transposition activity. This feature could be illustrated by a bacterial conjugation study using an Escherichia coli strain that carries the transposable element Tn5 as the donor. When the donor cultures were exposed to a low-frequency (50 Hz) magnetic field of 1.2 mT, Tn5 located on the bacterial chromosome was stimulated to transpose and settled on the extrachromosomal episome, and eventually transferred to the recipient cell through conjugation. Such transposition activity stimulation was mediated by the induced synthesis and accumulation of the heat shock proteins DnaK/J.
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Affiliation(s)
- K C Chow
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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LaBella FS, Queen GM, Brandes LJ. Interactive binding at cytochrome P-450 of cell growth regulatory bioamines, steroid hormones, antihormones, and drugs. J Cell Biochem 2000. [DOI: 10.1002/(sici)1097-4644(20000315)76:4<686::aid-jcb16>3.0.co;2-v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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