الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
The effect of extremely low frequency electromagnetic field of different intensities on Escherichia coli and Pseudomonas aeruginosa (as gram-negative bacteria) and Bacillus subtilis (as gram-positive bacteria) was investigated to find out the effective magnetic field strength that alters the running physiological processes of every microorganism. Equal volumes of every microorganism were exposed for one hour at their maximum rate of active growth to the electromagnetic field (2 - 10 mT, 50 Hz). The results indicated that no remarkable differences were found in the growth of P. aeruginosa, Moreover, a remarkable inhibition in the growth of exposed E. coli and B. subtilis cells relative to unexposed was achieved at (2 mT) and (4 mT) respectively as compared with other intensities, so more investigations were made at these magnetic field inductions. Remarkable changes in the growth characteristics curve for exposed E. coli cells at (8 hrs) and B. subtilis cells relative to unexposed could be easily detected as the absorbance decreased which indicate a decrease in the cells number and consequently an inhibition case for the bacteria. Also, the absorbance increased for exposed E. coli cells at (18 hr) relative to unexposed which indicate an increase in the cells number and consequently a stimulation case for the bacteria. The antibiotic sensitivity test of E. coli and B. subtilis cells indicated either inhibition or stimulation case for the bacteria depending on the drug mode of action. The results of the disc electrophoresis pattern and the molecular weight distribution of the WSPs. extracted from E. coli cells before and after exposure to ELF-EMF showed fluctuations in the molecular weights for exposure at the period of (18 hr) as compared to before exposure more than for exposure at the period of (8 hrs), as, there were sharp decreases in the number of protein bands and in their protein amount after exposure at the period (8 hrs). However, after exposure at the period (18 hr), the number of protein bands and protein amount increased as compared to before exposure. Also, the results of the U.V. absorption spectra for WSPs. extracted from exposed E. coli cells indicated that there was a decreasing in the intensity of the protein band for the exposed volume at the period of (8 hrs) relative to the unexposed in addition to fluctuation of the band towards higher wavelengths. Also, there was an increasing in the intensity of the protein band for the exposed volume at the period of (18 hr) relative to the unexposed in addition to fluctuation of the band towards higher wavelengths.
Key words: extremely low frequency, electromagnetic field, E. coli, P. aeruginosa, B. subtilis, , growth characteristics, antibiotic sensitivity, electrophoresis, U.V. absorption spectra, WSPs.