Lecture 2 & 7 Virology

What are Viruses?

What are Viruses?

Small Infectious agents consisting of the nucleic acid genome. Some viruses carry enzymes that aid in replication such as reverse transcriptase.

What is a capsid

A layer of protein made up of capsomeresand provides protection.

What is an envelope & what does it help do

An additional layer of protein and lipids surrounds the nucleic acid genome. Helps with the fusion of cellular receptors for viral entry in a cell type.

Where does Poxivirus replicate?

Cytoplasm only

Dmitri Iwanowski

One of the founders of Virology, studied tobacco plants can trasmit diseaseto other plants after passage.

Martinus Beijerinck

Known as the father of virology, found that tobacco plant disease can reproduce only in the host.

Felix d’Herelle

Recognizes viruses which infect bacteria which he calls bacteriophages.

Wendell Stanley

Crystallizes Tobacco Mosaic Virus (TMV) and shows that it ramins infectious.

Max Theiler

First to propogate yellow fever virus in chick embryos & create a vaccine.

Salvador Luria & Alfred Hershey

Demonstrate bacteriophages mutate

Alfred Hershey & Martha Chase

Demonstrate DNA was genetic material of a bacteriophage.

Jonas Folk

Discovered Polio Vaccine

Heinz Fraenkel-Conrat & R.C. Williams

Shows Tobacco Mosaic Virus RNA & Coat Protein were incubated together.

Baruch Blumberg

Discovers hepatitis B Virus

Howard Temin & David Baltimore

Discovered reverse transciptase in retrovirus

Luc Montaigner & Robert Gallo

Discovered Human immunodeficiency virus

Antigenic Shift (Recombination)

Generates viruses with entriely new genetic makeup, creation of a new strain.

Antigenic Drift (Accumulated Mutations)

Slow mutations with slightly modified genetic makeup, create a new strain similar to the parent

Viral Tropism

Infection of only one type at the cellular level, tissue level or host level.

Wide Genetic Bottle Neck

Start w/a lot of different virus populations, end up with a lot of different virus populations.

Tight Genetic Bottle neck

Selective to a few viruses that have the “founding principle” to become the “founding population”. Not all viruses will make it through the bottleneck.

Heterogeneity in host & virus.

The same virus that comes in does not become the same virus coming out.

Innate antiviral immune signaling pathways

Virus comes into contact w/double stranded dna, activates sting pathways. Virus comes onto double stranded RNA, could cause cell to kill itself.

Immune Escape

Neutralizing antibodies bind to surface of spike protein, now spikes of viral protein can’t bind to the host.

Immune Evasion

Starts at the host cell and acts like a shield, just blocking and deflecting viruses.

Red Queen Pinrciple of the Evolutionary Arms Race

As vaccines continue to become developed, viruses will continue to mutant to out grow the vaccine rate and become stronger.

What makes Zika virus so special?

It has a very large range of tropism allowing it to infect multiple things at multiple cellular levels.