[A method for studying the effect of the geomagnetic field on the vital activities of microorganisms in the enteric family].

The proposed method makes it possible to find out the direct influence of the geomagnetic field (GMF) on microorganisms of the family Enterobacteriaceae (the genera Escherichia, Shigella, Salmonella). Different disturbances in the state of GMF, both in amplitude and frequency range, were modeled under laboratory conditions. Microbial cells were cultivated in sterile artesian-well water or physiological saline with no organic substrate added. Experiments were performed at room temperature for 5 and more days. In these experiments the standard dose of microbial suspension was inoculated daily into Endo medium. The differences in the reproductive capacity and survival time of microorganisms in the test and control vials were compared with the indices of geomagnetic disturbances. If the experiments were started 2-4 days before the appearance of geomagnetic disturbances, the suppression of the reproductive capacity of microorganisms occurred, then followed its stimulation; this phenomenon particularly affected Escherichia coli and Shigella sonnei. In case of the quiet state of GMF the suppression of reproductive capacity is commonly observed. If the beginning of the experiment coincides with the appearance of a magnetic storm, a sharp decrease in the reproductive capacity of microorganisms and the death of the population within 1-5 days usually occurred. The survival rate of microorganisms depended on the state of GMF disturbances. The survival time of cell generations during disturbances of GMF was considerably longer. Under the conditions of a superimposed magnetic field the reproductive capacity of microorganisms outstrips, as a rule, that developing under the conditions of the compensation of the field. Studies on the biological activity of infralow frequency showed that the multidirectional reproductivity effect was observed due to constant changes in the geomagnetic background.