CATION TRANSPORT IN ESCHERICHIA COLI. IV. KINETICS OF NET K UPTAKE.

The resuspension of K-poor, Na-rich stationary phase E. coli in fresh medium at pH 7.0 results in a rapid uptake of K and extrusion of Na by the cells.

Purification of gamma globulin fragments by gel filtration.

Treatment with papain of human 7 S gamma globulin which has specific hemagglutinating antibody activity results in 3.5 S univalent fragments contaminated by intact bivalent globulin. The technique described in this report permits separation of univalent antibody fragments from the contaminating undigested molecule.

Cation transport in Escherichia coli. III. Potassium fluxes in the steadystate.

The present study is concerned with the measurement of the unidirectional K flux in E. coli. Methods are described by means of which a fairly dense suspension of cells may be maintained in a well defined steady-state with respect to the intracellular K concentration and the pH of the medium.

Cation transport in Escherichia coli. II. Intracellular chloride concentration.

The intracellular Cl concentration in E. coli has been studied as a function of the Cl concentration in the growth medium and the age of the bacterial culture. The ratio of extracellular to intracellular Cl concentration is shown to be 3.