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High magnetic field induced changes of gene expression in arabidopsis.

Paul AL, Ferl RJ, Meisel MW - Biomagn Res Technol (2006)

Bottom Line: The data suggest that magnetic fields in excess of 15 Tesla have far-reaching effect on the genome.The wide-spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism, are prominent examples.The roles of magnetic field orientation of macromolecules and magnetophoretic effects are discussed as possible factors that contribute to the mounting of this response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Horticultural Sciences and The Biotechnology Program, University of Florida, Gainesville, FL 32611-0690, USA. alp@ufl.edu

ABSTRACT

Background: High magnetic fields are becoming increasingly prevalent components of non-invasive, biomedical imaging tools (such as MRI), thus, an understanding of the molecular impacts associated with these field strengths in biological systems is of central importance. The biological impact of magnetic field strengths up to 30 Tesla were investigated in this study through the use of transgenic Arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the beta-glucuronidase (GUS) gene reporter.

Methods: Magnetic field induced Adh/GUS activity was evaluated with histochemical staining to assess tissue specific expression and distribution, and with quantitative, spectrofluometric assays to measure degree of activation. The evaluation of global changes in the Arabidopsis genome in response to exposure to high magnetic fields was facilitated with Affymetrix Gene Chip microarrays. Quantitative analyses of gene expression were performed with quantitative real-time polymerase-chain-reaction (qRT-PCR).

Results: Field strengths in excess of about 15 Tesla induce expression of the Adh/GUS transgene in the roots and leaves. From the microarray analyses that surveyed 8000 genes, 114 genes were differentially expressed to a degree greater than 2.5 fold over the control. These results were quantitatively corroborated by qRT-PCR examination of 4 of the 114 genes.

Conclusion: The data suggest that magnetic fields in excess of 15 Tesla have far-reaching effect on the genome. The wide-spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism, are prominent examples. The roles of magnetic field orientation of macromolecules and magnetophoretic effects are discussed as possible factors that contribute to the mounting of this response.

No MeSH data available.


Related in: MedlinePlus

Qualitative examples of GUS expression. Histochemical staining of the controls indicates that Adh/GUS was not expressed in these plants (a – b). An increase in magnetic field strength induces expression of the Adh/GUS transgene (e.g. 20 Tesla for 2.5 hours, c – d). The increased magnification of the plants shown in b and d (second row) provide closer inspection of GUS localization in the roots and leaves of these samples. The middle panel (e) provides a top-view of the five 21 day-old plants just prior to insertion into the bore of the magnet. The right hand panel (f) shows the plants from the side.
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Figure 1: Qualitative examples of GUS expression. Histochemical staining of the controls indicates that Adh/GUS was not expressed in these plants (a – b). An increase in magnetic field strength induces expression of the Adh/GUS transgene (e.g. 20 Tesla for 2.5 hours, c – d). The increased magnification of the plants shown in b and d (second row) provide closer inspection of GUS localization in the roots and leaves of these samples. The middle panel (e) provides a top-view of the five 21 day-old plants just prior to insertion into the bore of the magnet. The right hand panel (f) shows the plants from the side.

Mentions: In a series of experiments, 21 day-old plants were exposed for durations of 2.5 hours per run in the 50 mm diameter bore resistive magnets at the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, and in the 88 mm diameter bore superconducting solenoid located at the University of Florida. As described in the Materials and Methods section, the local environmental variables of temperature, light intensity, atmosphere, and humidity were controlled, and did not impact transgene expression. Figure 1 provides qualitative examples of the stress response mounted by the plants exposed to high magnetic fields. The histochemical staining shown in Figure 1 illustrates that GUS is being expressed in both leaf and root tissues in these plants. The baseline corrected, quantitative results are provided in Figure 2. Each data point in Figure 2 represents the average of the results from three plants, and the standard deviation is given by the uncertainty limits. Nonparametric statistical methods have been used to test the hypothesis of an association between the GUS activity and the magnetic field. For the leaves (Figure 2a), the Spearman correlation coefficient of 0.58 (P = 0.001) indicates that there exists a significant association between these two variables [26,27]. For the roots (Figure 2b), the Spearman correlation coefficient of 0.40 (P = 0.033) suggests a somewhat weaker association [26,27].


High magnetic field induced changes of gene expression in arabidopsis.

Paul AL, Ferl RJ, Meisel MW - Biomagn Res Technol (2006)

Qualitative examples of GUS expression. Histochemical staining of the controls indicates that Adh/GUS was not expressed in these plants (a – b). An increase in magnetic field strength induces expression of the Adh/GUS transgene (e.g. 20 Tesla for 2.5 hours, c – d). The increased magnification of the plants shown in b and d (second row) provide closer inspection of GUS localization in the roots and leaves of these samples. The middle panel (e) provides a top-view of the five 21 day-old plants just prior to insertion into the bore of the magnet. The right hand panel (f) shows the plants from the side.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1764872&req=5

Figure 1: Qualitative examples of GUS expression. Histochemical staining of the controls indicates that Adh/GUS was not expressed in these plants (a – b). An increase in magnetic field strength induces expression of the Adh/GUS transgene (e.g. 20 Tesla for 2.5 hours, c – d). The increased magnification of the plants shown in b and d (second row) provide closer inspection of GUS localization in the roots and leaves of these samples. The middle panel (e) provides a top-view of the five 21 day-old plants just prior to insertion into the bore of the magnet. The right hand panel (f) shows the plants from the side.
Mentions: In a series of experiments, 21 day-old plants were exposed for durations of 2.5 hours per run in the 50 mm diameter bore resistive magnets at the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, and in the 88 mm diameter bore superconducting solenoid located at the University of Florida. As described in the Materials and Methods section, the local environmental variables of temperature, light intensity, atmosphere, and humidity were controlled, and did not impact transgene expression. Figure 1 provides qualitative examples of the stress response mounted by the plants exposed to high magnetic fields. The histochemical staining shown in Figure 1 illustrates that GUS is being expressed in both leaf and root tissues in these plants. The baseline corrected, quantitative results are provided in Figure 2. Each data point in Figure 2 represents the average of the results from three plants, and the standard deviation is given by the uncertainty limits. Nonparametric statistical methods have been used to test the hypothesis of an association between the GUS activity and the magnetic field. For the leaves (Figure 2a), the Spearman correlation coefficient of 0.58 (P = 0.001) indicates that there exists a significant association between these two variables [26,27]. For the roots (Figure 2b), the Spearman correlation coefficient of 0.40 (P = 0.033) suggests a somewhat weaker association [26,27].

Bottom Line: The data suggest that magnetic fields in excess of 15 Tesla have far-reaching effect on the genome.The wide-spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism, are prominent examples.The roles of magnetic field orientation of macromolecules and magnetophoretic effects are discussed as possible factors that contribute to the mounting of this response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Horticultural Sciences and The Biotechnology Program, University of Florida, Gainesville, FL 32611-0690, USA. alp@ufl.edu

ABSTRACT

Background: High magnetic fields are becoming increasingly prevalent components of non-invasive, biomedical imaging tools (such as MRI), thus, an understanding of the molecular impacts associated with these field strengths in biological systems is of central importance. The biological impact of magnetic field strengths up to 30 Tesla were investigated in this study through the use of transgenic Arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the beta-glucuronidase (GUS) gene reporter.

Methods: Magnetic field induced Adh/GUS activity was evaluated with histochemical staining to assess tissue specific expression and distribution, and with quantitative, spectrofluometric assays to measure degree of activation. The evaluation of global changes in the Arabidopsis genome in response to exposure to high magnetic fields was facilitated with Affymetrix Gene Chip microarrays. Quantitative analyses of gene expression were performed with quantitative real-time polymerase-chain-reaction (qRT-PCR).

Results: Field strengths in excess of about 15 Tesla induce expression of the Adh/GUS transgene in the roots and leaves. From the microarray analyses that surveyed 8000 genes, 114 genes were differentially expressed to a degree greater than 2.5 fold over the control. These results were quantitatively corroborated by qRT-PCR examination of 4 of the 114 genes.

Conclusion: The data suggest that magnetic fields in excess of 15 Tesla have far-reaching effect on the genome. The wide-spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism, are prominent examples. The roles of magnetic field orientation of macromolecules and magnetophoretic effects are discussed as possible factors that contribute to the mounting of this response.

No MeSH data available.


Related in: MedlinePlus