Lecture Notes Sept 21

We have a great discussion of T4 bacteriophages and E. coli, and talk through the background information underlying our experiments for this week and next week. Also, there’s an interpretive dance involving pili and bacterial motility. Bumper music by Muse because it’s just appropriate for the subject material and for a rainy Monday.
My Notes
E. Coli Bacteria (Gram Negative) are killed by a virus-name of the virus is T4 bacteriaphage
When the T4 Bacteriaphage effects the E.Coli: (See Diagram)
Adheres to a protein on the surface of a bacteria
T4 DNA: copied by bacterial enzymes and translated by bacterial ribosomes Lots of T4 Bacteriophages inside E.Coli
T4 Bacteriaphage sticking to protein in outer membrane of E. Coli
Why T4 bacteriophage kills E. Coli is because its using the E.coli to copy itself and a direct consequence of the copying is the death of the e.coli bacterium when when it dies, that’s going to release virus particles out into the world to infect more ecoli
Experiment in lab this week:
Can E.Coli become resistant to T4 bacteria phage?
If E. Coli do become resistant to T4, why?
Are they “immune” after, virus attack and able to pass that acquired immunity on to offspring?
Is it just that some E. coli are randomly “born” resistant to T4?
In Class Questions:
Can Bacteria phages affect our human cells?
Will we see E.coli that come resistant to T4 phages?
If so, is it:
“acquired immunity?”
“bacterial communication/gene sharing?
all just random who lives who dies
V. Bacterial adhesion to surfaces
a. “Adhesins” are usually integral or peripheral membrane proteins
-membrane cell wall proteins used to stick to surfaces: typically peripheral membrane proteins:
Ex. Adhesions on ends of pili
(See picture on handout)
Interpretive Dance-Imagine you’re a bacterium sticking to surfaces: Stick out your pillis and then retract it
Pili are rare retractable extensions of bacterial cell envelope
A bacterium with a circular chromosome and a plasmid and another one with no plasmid, the bacterium with the plasmid could build a pilli extension out and touch the other bacterium, because of them being able to stick to the other and build a bridge they are able to make a copy and send a copy of the plasmid over to the other bacterium and then the bridge will detach.

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