lecture 2: appendages and inclusions

Question 1

FlhF, FlhG

Answer 1

control where the flagella is made (initiate flagella construction)

Question 2

Flagellar assembly

Answer 2

1. pre-T3SS assembly: the basal body (MS, C rings) and motor components are constructed, but the channel in the MS ring is closed.
2. Rod assembly: channel opens and rod substrates assemble. FlgG polymerizes until a specific length is reached. the hook cap is exported and the P ring is assembled
3. Hook assembly: promoted by the hook cap
4. filament assembly:

Question 3

CheA

Answer 3

1. without an attractant, CheA is active and phosphorylation casacde to Che Y
2. CheY binds to flagellar motor and induces CW rotation, causing the bacteria to tumble.
3. When there is an attractant, CheA is inactive and so is CheY.
4. CheR will methylate CheA when there is attractant present and reactivate CheA. This allows the bacteria to tumble even when there is attractant present, so it can find areas with higher amounts of attractant.
5. CheB removes methyl groups from the CheA
6. Regulated by CheZ, which dephosphorylates CheY.

Question 4

mreB

Answer 4

actin homologue
involved in cell shape and chromosome partitioning
E. coli mreB mutants are non-viable
how to study? tag the protein with GFP

Question 5

ParM

Answer 5

plasmid partitioning - inheritance of low copy # plasmids

1. ParM subunits form filamentous proteins
2. the filament polymerization is fueled by hydrolysis of ATP on active ParM
3. ParC is attached to the capped end of the filament and centromere of the plasmid
4. polymerization pushes the plasmid progeny to opposite poles.

Question 6

MamJ and MamK

Answer 6

Mam attaches empty magnetosome vesicles to the cytoskeleton filament MamK in the center of the cell
MamK requires K+ to assemble

Question 7

magnetosome

Answer 7

tiny magnet surrounded by lipid and protein

Question 8

spore structure

Answer 8

core, core wall, cortex, coat, exosporium
core has sasp that convert the DNA from B-form to A form. sasps also provide c and energy for outgrowth of vegetative cells

Question 9

SASPs

Answer 9

convert DNA from B form to A form and provide C and energy for outgrowth of vegetative cells.

Question 10

CmpA

Answer 10

makes sure the spore coat is properly assembled. If the spore coat is not properly assembled, it recruits proteases in order to degrade the spore coat and causes apoptosis of the cell.

Question 11

methods of measuring cell growth

Answer 11

1. total cell count (direct microscopic count)
2. viable count
3. dry weight
4. turbidity

Question 12

LB experiment

Answer 12

1. noticed that e coli wasn’t growing to expected OD of 7 in LB and that it plateaued
2. noticed that the mass per cell decreases as OD increases
3. Thought maybe glucose was limiting - but when they added more, the culture plateaued again. (higher, so it was part of the answer)

Question 13

growth factors?

Answer 13

amino acids
purines/pyrimidines
vitamins
others: heme, cholesterol, polyamines