Fusion of single influenza virus particles with BLM

Fusion of influenza virus envelope and endosome membrane is one of the key stages of viral infection. In the present study, a special experimental app roach which allows to monitor fusion between fluorescently labeled virus pa rticles and bilayer lipid membrane (BLM) was developed. A small patch of th e BLM with few virus particles adsorbed was localized inside a glass pipett e brought into a close contact with the BLM. Low pH of the buffer in the pi pette triggered fusion between the trapped particles and the patch. The fus ion can be detected by changes of integral fluorescence and conductance of the patch. We found that the fluorescence of the BLM patches increased afte r triggering of the fusion. The fluorescence increase was accompanied by co nductance changes. Typical record of the patch conductance contained 2-5 pe riods of channel-like activity, each period being likely associated with a single virus particle fusion. The complete blockage of this activity by ama ntadine suggests that M2 channels in the virus envelope membrane would medi ate the conductance increase.