To study the effect of extremely low frequency electromagnetic fields on the growth rate of gram-positive and gram-negative bacteria and to determine any morphological changes that might have been caused by exposure.
Exposure duration: continuous for up to 6 h
|Exposure duration||continuous for up to 6 h|
|Setup||Helmholtz coils with an inner diameter of 20 cm and 400 turns of copper wire positioned parallel to the ground; 15 ml falcon tube containing culture medium of 1 cm height centered in the vertical axis of the coil system; exposure system placed in an incubator|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||0.5 mT||-||measured||-||+/- 0.05 mT|
A decrease in growth rate was found for all bacterial strains during extremely low frequency electromagnetic field exposure compared with control samples. The decrease in growth rate persisted following exposure. Significant ultrastructural changes were observed in all exposed bacterial strains (e.g. disintegration of the cell wall, retraction of the cytoplasmic membrane from the cell wall, cell wall enlargement, cytoplasmic changes).
The data showed that extremely low frequency electromagnetic fields induce a decrease in growth rate and morphological changes for both gram-negative and gram-positive bacteria.