SUMMARY: , suspended in meat extract broth or in a defined medium, bound cobalt to an extent dependent on the cell concentration and on the concentration of cobalt in the medium. An increase in concentration of cobalt or a decrease in the number of cells per unit volume resulted in a greater amount of cobalt ion bound per unit of cellular material. The composition of the suspending medium with regard to the cobalt combining groups present, as well as the availability of other metallic ions, markedly affected the amount of cobalt bound by the cells. Magnesium was particularly effective in diminishing the cobalt-combining capacity of the cells. An exposure time of 15 min. was sufficient for the major portion of the ion to be taken up by the cells. In an anaerobic medium, the cells-bound approximately one-half as much cobalt as in an aerobic medium. Raising the pH value of the medium from 5.0 to 7.0 resulted in an increased uptake of the metal by the cells. Cobalt taken up by the cells could be removed to an extent of 70--80% by dilution in distilled water and almost completely by 0.1 -HCl. A derived strain of Proteus, capable of growth in relatively high concentrations of cobalt, bound smaller quantities of the ion at each level tested than did the parent strain. However, at the growth inhibitory level peculiar to each strain, the resistant form took up a much greater quantity of the metal than did the sensitive strain. This fact indicates that resistance to cobalt cannot be explained merely on the basis of the cobalt-concentrating ability of the cells.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error