Pictures Considered #13 : How Many Things Can Be Illustrated In One Picture?

by Elio

This transmission EM of a thin section of a T2 phage infecting an E. coli cell was produced by Lee Simon in the late 1960’s. It is noteworthy for depicting a remarkably large number of properties of the phage and of the infection process. Can you figure out how many such characteristics are illustrated or at least strongly hinted at? I came up with nearly a dozen (see below). How about you?

I am grateful to Lee for letting me use this wonderful image.

Phage properties illustrated in this picture:

1. These phages have a head, a tail, and tail fibers.
2. The long tail fibers are bent at a sharp angle.
3. The tail is attached to the head by a narrow neck collar.
4. The head appears to be icosahedral.
5. Absorption is tail first.
6. In virions absorbed to the cell, the tail sheath becomes contracted.
7. In absorbed virions, the head appears empty, although not always totally.
8. Apparently empty heads are seen intracellularly.
9. Phages “mature” intracellularly near or within the nucleoid.
10. The filling of the phage heads appears to be a rapid process (only a few intermediates between empty and filled heads are seen.
11. The host cell appears to remain intact throughout an advanced stage of infection (although small holes in the envelopes cannot be excluded).
12. A sectioned infected E. coli looks like a pizza with pepperoni.

 
 

 
 

Comments

[P. Nart]

Wonderful example of how an image can be highly descriptive and explanatory of natural phenomena and processes! Thanks!

Elio replies:

Nothing could please me more than this comment. This is the whole point of this series, "Pictures Considered!" Many thanks,

Elio