Infective Cycle - Adsorption,Spikes,Electron Microscopy,Sites of Adhesion,Cell Membrane

Infective Cycle - Adsorption

	Infective Cycle - Adsorption - The phage adsorbs to the host cell by its spikes. Electron microscopy observations show that phage attachment is by only one of the 12 icosahedral vertices. This indicates that one of the 12 spikes differs from the others, and is specialized for attachment.
However, it is also likely that anyone of the 12 spikes can promote attachment. Attachment takes place to, a receptor on the bacterial cell wall and is at first reversible. Attachment requires either Ca++ or Mg++. It has been suggested that adsorption takes place at sites of adhesion of the cell wall and cell membrane