The T-Phage Page

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Since the first time I saw a diagram of their actions in a high school biology textbook, I've been fascinated by T-phages. This page attempts to give a quick introduction to these virii, as well as a large number of pointers to other information on T-phages and other bacteriophages.

What They Are

A bacteriophage is a virus that attacks bacteria as a host cell. T-phages are a specific class of bacteriophages with icosahedral heads, double-stranded DNA, and tails. The most commonly studied T-phages are T4 and T7, both of whom infect E. coli, everybody's favorite laboratory bacterium. They resemble microscopic arthropods, with a head composed of 20 triangular surfaces, a tail, and limb-like tail fibers.

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Depicted above is a bacteriophage T4 phage, which has six small spikes at the base of a contractile tail used to attach to the host cell (see what T-phages do), and six larger tail fibers used to sense the presence of a host cell.

What They Do

The term phage comes from Greek phagein, literally "to eat," but with a more parasitic connotation—more "to grow at the expense of." T-phages are evil. Their modus operandi is brutal and direct. They operate by infiltrating a host cell, converting it into a T-phage factory, and then destroying it—releasing hordes of newly constructed T-phages. It's a little von Neumann machine!

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A single host cell has enough raw material to produce maybe 50 new T-phages. This is amazing! For each one T-phage which sacrifices itself, 50 more T-phages come into being to do the same. You can see how these phages can decimate a bacterial population in a short period of time.

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Links and References

It's hard to find information about viruses that is intelligent, and at the same time, accessible. Here are some links to interesting pages about or relating to T-phages or discussion of bacteriophages.

• Divison M (Bacteriophage) of the American Society for Microbiology is composed of bacteriophage researchers. The site features some fascinating photographs of bacteriophages at work. The phage art gallary is also a riot.
• The Bacteriophage Ecology Group is an organization of bacteriophage ecologists. This site has lots of pictures and information and a nice, tongue-in-cheek atmosphere. They understand that devoting your life to studying "the parasites of unicellular organisms (UOPs)" is just a little silly.
• Here are data sheets on Coliphage T4 and Coliphage T7 from the International Committee on Taxonomy of Viruses as hosted by the Australian National University.
• The original Bacteriophage Home Page from the Evergreen State College has news, links, and the draft of a fascinating paper entitled Phage Therapy: Bacteriophages as Antibiotics discussing using viruses for destroying pathogenic bacteria.
• I found one good general pathogenic virus overview from, of all things, a silly creationist website. It's nevertheless a pretty well-written article which takes the interesting approach of arguing for microevolution.

And here are some miscellaneous definitions, animations, and images culled from on-line lecture notes, Encyclopedias, and other random sources.

• This phenomenal microbiology lecture from the Community College of Baltimore County has some awesome animations showing the life cycle of a bacteriophage, specifically depicting T-phages.
• Amusingly, a microbiology class from my alma mater includes in its lecture notes a poem describing the stages of lytic growth. Here is an excerpt:

  Lysogeny is not a pretty ending
  When phage, their armies are sending.
  Poisson distribution will I solve to know
  What stops the bacterial lawn from its growth.

• T-Phages are fun to draw. Here's a short introduction to the bacteriophage T4 virus from dFORM, a science and education VRML design house.
• Britannica.com has a well-researched encyclopedia entry on phages.
• An educational CD called Cells Alive! has a bacteriophage page with some cartoons illustrating how they work.
• Here is another biochem lecture about bacteriophages with some more good information and a few pictures, this time from the Memorial University of Newfoundland.

Finally, I can't end this without a mention of the Memetic Lexicon by Glenn Grant. This is a fascinating essay about viral memetic propagation. Here is an ASCII only version hosted by the Electronic Frontier Foundation.

Of course, if all of those pages leave you hungering for more, you can always do your own Google search on bacteriophages. If you have any questions about this page or its author, you can e-mail Andrew Ho or visit Andrew Ho's website.

All text and images are copyright (C) 2000-2006 Andrew Ho.
Feel free to use them for any non-profit purpose.

Andrew Ho (andrew@zeuscat.com)