The influence of magnesium on cell division. 2. The effect of magnesium on the growth and cell division of various bacterial species in complex

SUMMARY: Magnesium is essential for the normal cell division of bacilli in complex media. Under conditions of magnesium deficiency or magnesium excess, cell division is inhibited and filamentous cells may be formed. Under the same conditions there is no appreciable interference with the division of chromatinic bodies. The magnesium requirements of the Gram-positive bacteria are considerably greater than those of the Gram-negative bacteria, possibly because the former incorporate magnesium into the structure of the Gram complex. In a previous communication (Webb, 1 9 4 8 ~ ) it was shown that magnesium was essential for the normal cell division of Clostridium welchii. In complex media deficient in ionic magnesium, CZ. welchii grew in the form of long filaments, which reverted to cells of normal morphology when subcultured in a medium containing 0.0015 yo (w/v) magnesium ion. In extending these studies, the influence of magnesium on the growth and division of various other species of bacteria in complex media has been determined. The results, described here, suggest that magnesium is essential for the normal cell division of all the rod