Coliphage lambda ghosts obtained by osmotic shock or LiCl treatment are devoid of J- and H-gene products.

We have proved by acrylamide gel electrophoresis that DNA-free ghosts of bacteriophage lambda obtained by osmotic shock (S-ghosts), or by incubation in 5 M-L-Cl (L-ghosts) do not possess the proteins specified by the genes J and H. Electron microscopy of L-ghosts showed that they are devoid of the whole tail tip, composed of the basal part and the tail fibre. The lack of the J-gene product, which is believed to be the tail fibre, explains why S- and L-ghosts do not adsorb to susceptible bacteria. Our results suggest that the H-gene product, which is modified after translation, is situated in the basal part of the tail.