Central Dogma Lecture 10 CRISPR Paper

Question 1

What was the author of the paper’s goal?

Answer 1

-Strain optimization for industrial fermentation
-Looking for phage resistant yogurt/dairy starter cultures
-Streptococcus thermophilus is a low G+C gram positive bacterium and a key species exploited in the formulation of dairy culture systems for the production of yogurt and cheese

Question 2

Plaque Assay method

Answer 2

-Bacteria are mixed with a phage dilution, mixed with soft-agar, then spread on top of conventioal agar plate
-Infected bacteria burst and release progeny phage that infect adjacent bacteria
-Infection continues and produces a “zone of clearance” aka a plaque
-Virus titer is determined by counting plaques and by multiplying by the dilution factor
-Plaque counts from at least 3 replaicates at each dilution should be averaged

Question 3

Implications of paper

Answer 3

CRIPSPR is a nucleic acid specific and adaptive immune system

When invader DNA is cleaved, a piece of it is integrated as a new spacer where it serves as memory

Question 4

Why is CRISPR better than antibodies?

Answer 4

-All of us are not walking around with parent’s antibodies
-Bacteria: immunity is heritable

Question 5

What is the Red Queen

Answer 5

-For an evolutionary system, continuing development is needed just in order to maintain its fitness relative to the systems it is co-evolving with
-Basically we’re in an arms race with bacteria/viruses to one up eachother and survive