Characteristics of Escherichia coli B Resistant to Cobaltous Ion

Abstract

The cobalt-resistant mutant (resistant up to 1000 μg Co/ml) was obtained from E. coli B-ATCC 11246 by means of incubating the parent cells in the media which contains cobalt. The mutant produced by this way is resistant only to cobalt, but not to other metals such as Mg²⁺, Ca²⁺, Cr³⁺, Cr₂O₇^2-, Mn²⁺, Fe²⁺, Fe³⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺, and specifically suppresses Co²⁺ uptake. The difference in membrane proteins between the parent and resistant cells is observed. The granules densely stained are appeared in the parent cells incubated with Co²⁺ under the image of electron microscope.