Reference no: EM133058040

QUESTION 1
In the introduction of this manuscript the authors introduce the concept of transcription factors. Briefly DESCRIBE the difference between general and specific transcription factors.

QUESTION 2
In this manuscript the authors created a GFP-VirB construct expressed from the pBAD promoter in the low copy number plasmid pBAD/HisA. DEFINE what is meant by the term's "promoter" and "low copy number plasmid."

QUESTION 3
The authors made various GFP-VirB constructs and assessed their stability in figure 1.
a) Look at figure 1B. Why was an empty plasmid vector included in the experiments?

b) The authors concluded that the GFP-VirB fusion with the 12AA linker interfered with the functionality of the VirB protein. What evidence is there in figure 1B to support this conclusion?

QUESTION 4
This question concerns the results presented in figure 2.
a) Using your understanding of molecular cloning from your practical week how do you propose the authors managed to make the Shigella flexneri express the GFP-VirB constructs and the relevant control vectors?

b) Look carefully at figure 2A. Compare the expression pattern of the GFP in the bacteria in the three different conditions (GFP-VirB, GFP, Empty).

c) In figure 2C the authors suggest there is a "strong positive correlation between the number of foci and the mean cell length of the bacteria". How far do you agree with this suggestion? Use the results in figure 2 and your statistical understanding to inform your answer.

 Assess figure 4. What do the results in this figure suggest about the expression of GFP-VirB in this different strain of Shigella flexneri?

QUESTION 6
Examine figures 5-7. How do these figures support the conclusion that in order to regulate its activity VirB must bind to a specific DNA sequence in Shigella flexneri?

QUESTION 7
a) This manuscript would suggest that VirB could be involved in plasmid partitioning in a similar manner to ParB although this requires further characterisation. Suggest how VirB could perform a similar function to ParB. You should use your knowledge of the ParB system and the results of this manuscript to inform your answer.

b) How could you use bioinformatics and gene knockout technologies to confirm whether VirB could play a similar role to ParB in Shigella flexneri?