Letter to the editor: Fusion of Sendai viruses with model membranes

Subcellular distribution and possible role of gangliosides in the CNS

From cell fractionation studies it is concluded that gangliosides have a wide distribution in neuronal plasma membranes, being concentrated in the microsomal and the nerve-ending membranes rich in acetylcholinesterase. When properly purified synaptic vesicles are devoid of gangliosides and acetylcholinesterase; thus the possible relationship between gangliosides and the cholinergic transmitter should be discarded. There are important evidences that specific gangliosides may play a role in the binding of certain toxins and viruses to the plasma membrane; however, their possible role as synaptic receptors is not supported by our experiments. The central receptor for 5HT appears not to be related to brain gangliosides and is represented by a hydrophobic protein (i.e. proteolipid) present in the synaptic junction.

Fusion of dipalmitoylphosphatidylcholine vesicle membranes induced by concanavalin A

The temperature dependence of fatty acid spin label resonance spectra and freeze fracture micrographs of sonicated dipalmitoylphosphatidylcholine vesicles in the absence and presence of concanavalin A demonstrate a strong interaction of concanavalin A with these lipid membranes, which results in fusion of the vesicles. The rate of this reaction as followed with use of magnetic resonance exhibits a pronounced maximum at 36 degrees, the midpoint of the phase transition range of dipalmitoylphosphatidylcholine vesicles. This maximum is discussed in terms of structural fluctuations, which are maximal in the phase transition range of the membranes.

Membrane mobility agents. II. Active promoters of cell fusion

The membrane mobility agent, A2C, actively promotes the fusion of hen erythrocytes under conditions similar to those used by Lucy et al. for glyceryl monooleate.