Unit 3 Lecture 10/30

1. Ground Zero
a. Chapter 1: Doctrix Robson’s Checkered Past
i. Herpes Simplex 1 from guy named Jeff
b. Chapter 2: Viral Replication
i. Viruses need a host cell to replicate
ii. b/c they need a host cell to copy genome, not quite alive
iii. 1) Virus attaches to a host cell because of specific protein receptors on the host cell
1. Interaction btw. Specific protein on host cell surface & viral protein allows this
2. Bacteriophage: capsid stays on outside host cell, DNA injected into cell
a. Capsid – protein shell surrounding viral genome
3. Viruses that infect eukaryotic cells:
a. That virus will be engulfed by the host cell and taken in by the host cell; enzyme sin our cells break down the capsid surrounding its genome
b. Capsid broken down by our enzymes; which frees the genetic material of that virus (some viruses have DNA genomes and some have RNA genomes)
iv. 2) Viral genes expressed (i.e., genetic material of virus transcribed & translated into protein) by host cell ribosomes (machinery), etc.
1. & viral genetic material copied by host cell enzymes (DNA polymerase, etc.)
v. 3) New viral genetic material (copied) packaged into new capsid proteins  resulting in new virus particles!
1. some viruses: DNA or genetic material in general of virus alone, in cell  new functional viruses
vi. 4) viruses released from host cell
1. Eukaryotes: viruses often “bud” off of host cell  not necessarily fatal to host cell but viral infection does keep cell from doing its job  can  death (ex. HIV)
c. Chapter 3: Viral Affinity for Host Cells
i. Viruses that we get can only infect humans and may only be able to infect certain cell types in humans
ii. Because there has to be a specific interaction between host cell and viral cell it limits the cells that the virus can infect
iii. Viral interactions with host cell proteins very specific, so specific viruses can only infect specific cells
1. Herpes Simplex 1: can only infect epithelial cells and neurons; cold sore virus
a.  infects epithelial cells and neurons because these are the only cells that have the right proteins on their surface for the herpes simplex virus to attach to replicate and so forth
b. Fled from the epithelial cells and to neurons in the spinal cord that feeds the lip since they were attached at the lip because the immune system was attaching them there
2. The Curious Case of Dr. Wimmer
a. Chapter 1: Host cells, host species, and the potential for disease eradication
i. Eradication – to eliminate something utterly from planet earth; to destroy it
1. Destroy a disease so that it can never infect anyone ever again
2. Destroy viruses access to new host cells so they will all die
a. Hard if a viral disease has multiple host species
3. Good candidates for eradication:
a. Viral diseases that only infect humans and have reliable vaccine against
4. All had to do was break mode of transmission everywhere so that polio could not move from one host to another host it would be wiped off the face of the earth
b. Chapter 2: Polio
i. Polio virus: RNA genome; can only infect intestine epithelia cells and neurons
1. In nature can only do this in humans
ii. Causes low level gut symptoms that go away quickly
iii. If it is acquired when the child gets older causes paralysis of the neurons of the lower legs
iv. Eradication – to eliminate something utterly from planet earth; to destroy it
1. Destroy a disease so that it can never infect anyone ever again
c. Chapter3: Viral synthesis
3. Death Rides a Pied Horse
a. Chapter 1: The pox!
i. Large virus with double stranded DNA genome
ii. Only infects human epithelial cells
iii. Mortality Rates:
1. 30% in experienced population
2. 90% in naive population
b. Chapter 2: Hope springs eternal
c. Chapter 3: Victory
i. Wars stopped so that vaccine workers could come on and resume killing each other
ii. Small pox cases dropped dramatically after the small pox vaccination campaign
d. Chapter 4: Tragedy
i. Soviet’s kept a vial and the united states kept a vial to use as warfare
ii. The soviet’s vial was kept under lock and key until the soviet union fell
e. Chapter 5: The end?

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