Studies on isolated cell components: V. The effects of various solutions on the nuclear envelope of the isolated rat liver nucleus

Abstract

A number of salt solutions have been shown to cause tenuous blebs or blisters to rise from the surface of isolated rat liver nuclei. These have included solutions of NaCl, KCl, and K-phosphate (pH 7.0–7.4) in concentrations ranging from 0.001 M to 1.0 M, and CaCl 2 and MgCl 2 in concentrations ranging from 0.001 to 0.25 M. A large number of very small blebs were also observed in distilled water. The largest blebs were observed in dilute (0.001 to 0.01 M) solutions of MgCl 2 and CaCl 2. The addition of sucrose in a concentration of 0.145 M was found to inhibit effectively bleb formation in a number of salt solutions, and to cause bleb retraction when added to bleb-forming solutions. Sucrose, in a concentration as low as 0.05 M, has been shown to prevent bleb formation by 0.001 M MgCl 2. On the basis of index of refraction differences observed with the phase contrast microscope, it is concluded that the nuclear blebs are relatively impermeable to protein, but may contain protein which has previously penetrated the nuclear envelope. A possible mechanism of bleb formation is presented.