T4 Bacteriophage

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T4 Bacteriophage
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What is a Bacteriophage?

• A small virus that only infects bacteria
  wikipedia
• Phagein- to eat (greek)
• Two major types Lytic and Lysogenic

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Different Types of Bacteriophages

• Lytic- infect the cell and force the replication
  of the viruses until the cell lyses (or splits
  the cell open)
• Lysogenic- infect the cell and integrates its
  genetic material into the bacterial DNA,
  remaining dormant until the cell shows signs of
  stress, when the phage becomes active and begins
  making copies of itself.

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Infection Cycle

• Adsorption- tail fibers attaching to the
  bacterium, reversible attachment
• Irreversible Attachment- base plate irreversibly
  attaches to the bacterium
• Sheath Contraction- hollow tail fiber is pushed
  through the bacterial envelope
• Nucleic Acid Injection- goes from the head
  through the tail, into the bacterium

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E. Coli erupting
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Basic Structure
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Model vs. Reality
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Capsid
-

• Icosahedral head (20 triangles, symmetric)
• Protein on the outside of the capsid
• DNA on the inside- well protected

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Fibers

• Tail (Long fibers)
• Only one fiber has to touch to recognize the
  bacteria
• Makes a reversible bond with the bacteria
• Whiskers
• Shorter than the tail fibers(400nm)
• Six of them arranged around the capsid
• Short
• Arranged around the baseplate

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Sheath/Contraction

• 1000 angstroms long with a 210 angstrom diameter
• Twists as it compresses
• Inner tube is 43-96 angstroms in diameter

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Baseplate
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USES PAST AND PRESENT

• Reporter Bacteriophages
• Usage in Atomic Force Microscopy
• Hershey and Chase

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Reporter Bacteriophages

• Used to detect biomolecules
• No need for scientific instruments on the fly
• Versatile
• Can be very accurate if scientific instruments
  are used

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Atomic Force Microscopy

• Cell puncturing device
• Approx. 9.6nm in diameter (really small)
• Regular AFM diameter Approx. 20nm in Diameter

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Hershey-Chase Experiment
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Sources

• http//www.protein.bio.msu.ru/biokhimiya/contents/
  v69/full/69111463.html
• http//www.web-books.com/MoBio/Free/Ch1E1.htm
• http//www.stanford.edu/bohannan/Media/T4photo2.j
  peg
• http//news.uns.purdue.edu/UNS/newspix02/pix404.ht
  m
• http//pathmicro.med.sc.edu/mayer/phage.htm
• http//anatomias.no.sapo.pt/fagos.GIF
• www.cellsalive.com
• http//www.phages.org/PhageInfo.html
• http//www.evergreen.edu/phage/phagetherapy/phaget
  herapy.htm

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SEXY LADY(Our Model)