Effect of super high magnetic field on the growth of escherichia coli under various medium compositions and temperatures

Abstract

When two strains of Escherichia coli were grown under a super high magnetic field (11.7 Tesla) in complex medium, the growth was stimulated in comparison with that in the geomagnetic field. When the bacteria were grown in synthetic medium, the growth rates were reduced significantly. As a result of the addition of casamino acids to the synthetic medium, the growth was shifted from a reduced state to a stimulated one, suggesting that certain amino acids are responsible for the phenomenon. Twenty amino acids were thus added individually to minimal medium; some of these amino acids shifted the reduced growth state to accelerated or normal growth. The critical concentration of glutamic acid for the growth shift was determined to be 0.01–0.1 mg/l. When the bacteria were grown at temperatures lower than the optimal temperature for growth, the 11.7 T magnetic field enhanced the growth rate irrespective of media used, while at higher temperatures reduced growth became significant in accordance with the increase in temperature. A potential use of the high magnetic field as a control factor in biological system is suggested.