title: Evidence for a magnesium pump in Bacillus cereus T.
abstract: Unlike Escherichia coli, Bacillus cereus T appears to accumulate Mg(2+) in its cell sap against a concentration gradient. Over a range of Mg(2+) in the growth medium from 5 x 10(-5) to 1.35 x 10(-2)m, the concentration of Mg(2+) in the cell sap of B. cereus T was maintained at about 6 x 10(-3)m, and ribosome-bound Mg(2+) and spermidine, as well as the spermidine concentration in the cell sap, appear to be unaffected by the concentration of Mg(2+) in the growth medium. Inhibition of growth of E. coli by streptomycin is progressively reversed by increasing the concentration of Mg(2+) in the growth medium above 5 mm. The finding that similar increases of Mg(2+) in the growth medium did not reverse the inhibition of B. cereus T is also consistent with the conclusion that B. cereus T, unlike E. coli, accumulates Mg(2+) to a constant concentration in its cell sap.
mesh_terms: D000588:Amines / Q000378:metabolism; D001409:Bacillus cereus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D001693:Biological Transport, Active; D002247:Carbon Isotopes; D002498:Centrifugation; D003470:Culture Media; D003593:Cytoplasm / Q000378:metabolism
chemical_list: D000588:Amines; D002247:Carbon Isotopes; D003470:Culture Media