The phenomenon of ``rafting'' observed for the first time in living cells may lead to new methods of preventing transmission of infectious diseases including the mad cow disease that affects the brain, it is claimed. The discovery by Rajat Varma and Satyajit Mayor of the National Centre for Biological Sciences (NCBS), Bangalore, has been reported in the prestigious international science journal Nature.

The cell membrane is a dynamic structure made up of a variety of substances called lipids. Within this ``sea of lipids'' the Bangalore scientists found ``micro domains which act like moving platforms, or rafts, transporting proteins present on the surface to their destinations inside the cell. The rafts also act as relay stations for the transduction of signals through the cell,'' they say.

The classof proteins using the rafts for commuting are known as ``GPI-anchored proteins'' one of which is the scrapie protein that generates infectious prions, the causative agent of mad cow disease. According to the Bangalore scientists, transport of this protein can be prevented by reducing the level of cholesterol, one key component of the lipids, which is critically needed for ``construction'' of the raft thus, in theory this provides a way of stopping infection by the agent causing made cow disease.

Although the presence of rafts was long suspected, their actual detection was made only now by the Bangalore scientists using ``fluorescence resonance energy transfer microscopy,'' a new technique they had developed.

``With the discovery of rafts in membranes and the development of techniques to study the same, we will have a much more complete understanding of cell membrane structure and its influence on cellular function,'' Mayor said.

``These studies are likely to have significant impact on the understandingof many diseases that are related to raft-associated molecules, the most important of which may be cholesterol,'' he said.