This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Scribner, H. Articles by Silver, S. Search for Related Content PubMed PubMed Citation Articles by Scribner, H. Articles by Silver, S.

Magnesium Transport in Bacillus subtilis W23 During Growth and Sporulation

^a Division of Biological and Biomedical Sciences, Washington University, St. Louis, Missouri 63130

ABSTRACT

The active transport of magnesium by cells of Bacillus subtilis strain W23 occurs by a highly specific transport system (Mg²⁺ is favored over Mn²⁺, Co²⁺, or Ca²⁺) that is energy dependent (i.e., glucose is required in minimal medium and the system is inhibited by cyanide and m-chlorophenyl carbonylcyanidehydrazone). The rate of magnesium uptake by log-phase B. subtilis cells follows saturation kinetics with a K_m of 2.5 x 10^–4 M and a V_max of 4.4 µmol per min per g (dry weight) at 30 C. Manganese is a competitive inhibitor showing a K_i of 5 x 10^–4 M. During sporulation the rate of magnesium transport declines. This decline in rate is specific for the magnesium system as the manganese and calcium transport rates increase. The residual magnesium transport function in sporulating cells shows both an altered K_m and an altered V_max. The magnesium content of late sporulating cells is also lower than that for log-phase cells.

¹ Present address: Institut für Genetik der Universität zu Köln, 5 Köln 41, Weyertal 121, Germany.

This article has been cited by other articles:

• Smith, R. L., Gottlieb, E., Kucharski, L. M., Maguire, M. E. (1998). Functional Similarity between Archaeal and Bacterial CorA Magnesium Transporters. J. Bacteriol. 180: 2788-2791 [Abstract] [Full Text]