10.3 Noncontractile Tails Atlas of Bacterial and Archaeal Cell Structure Home

Noncontractile Tails

Some phage have tails that are not contractile, like this siphophage attacking a Shewanella oneidensis cell. The long, flexible tail still serves the essential function of crossing the barrier of the cell’s envelope, providing a conduit for the genome to enter the cell.

Note that you already saw a different type of phage attacking S. oneidensis. While most phage are adapted to infect one or a few closely-related species of bacteria or archaea, there are often multiple different types of phage adapted to attack each species. The diversity of phage is staggering, and they have diverged considerably through evolution. One lacks a single gene with detectable homology to any other in any known virus or cell.