Mechanisms of Membrane Fusion by an Electric Pulse

摘要

All of our experiments utilize erythrocyte ghost membranes. Dielectrophoresis isinduced with a 60 hertzs alternating electric current passed through a membrane suspension to induce pearl chain formation (which causes membranes to come into contact with each other). A strong direct current pulse passed in the same direction to these membranes in contact causes membrane fusion to take place with a yield which is measured. The pulses are exponentially-decaying, and the pulse duration is given as a decay half-time. We use fluorescence light microscopy and the fluorescent label DiI to label the membranes and provide a rigorous and unambiguous indicator of membrane fusion. The following six findings were made during this research effort: 1. The dielectrophoretic force between two erythrocyte membranes was measured at a low frequency (60 hertzs). 2. Further evidence was obtained that electroosmosis takes place during electroporation. 3. The earliest detectable evidence for membrane fusion takes place after a finite time interval following the application of the fusogenic electric pulse. 4. What are electrofusion yields when dissimilar membranes are the membrane substrates compared to similar membranes (similar fusions are A+A, B+B, compared to dissimilar fusions A+B). In this work, the heterofusion yield was nearly half way between the two homofusion yields. Keywords: Membrane; Electrofusion; Electric field; Physical chemistry; Biology; Electrochemical methods, Electroporation. (jg)