Chapter 1, Problem 1.21.1C

The diagram below illustrates a quorum sensing pathway from Staphylococcus aureus. Please answer the following questions. 1. Autoinduction is part of the quorum sensing system. Which promoter (P2 or P3) is critical for autoinduction? 2)This staphylococcus aureus grows on human wounds, causing severe infections. You would like to start a clinical trial to treat these wound infections. Please describe: a) What molecule do you recommend for the trial. Why? b) Your trial requires that Staphylococcus aureus be isolated from the wound and submitted to genome sequencing before admittance. Why? What are you testing for?  3) If a mutation arises where the Promoter P3 is constitutively active, how would that influence sensitivity to AIP? Please explain your rationale. 4) This pathway is sensitive to bacterial cell density. Describe two separate mutation that would render the pathway active independent of cell density. Briefly explain your rationale. Mutation 1 Mutation 2

There is currently a H5N1 cattle outbreak in North America. According to the CDC on Feb 26*: "A multistate outbreak of HPAI A(H5N1) bird flu in dairy cows was first reported on March 25, 2024. This is the first time that these bird flu viruses had been found in cows. In the United States, since 2022, USDA has reported HPAI A(H5N1) virus detections in more than 200 mammals." List and describe two mechanisms that could lead to this H5N1 influenza strain evolving to spread in human:  Mechanisms 1: Mechanisms 2: For the mutations to results in a human epidered they would need to change how the virus interacts with the human host. In the case of mutations that may promote an epidemic, provide an example for: a protein that might incur a mutation: how the mutation would change interactions with cells in the respiratory tract (name the receptor on human cells) List two phenotypic consequence from this mutation that would increase human risk

You have a bacterial strain with the CMU operon: a) As shown in the image below, the cmu operon encodes a peptide (Pep1), as well as a kinase and regulator corresponding to a two-component system. The cmu operon is activated when Pep 1 is added to the growth media. Pep1 is a peptide that when added extracellularly leads to activation of the Cmu operon. Pep1 cmu-kinase cmu-regulator You also have these genetic components in other strains: b) An alternative sigma factor, with a promoter activated by the cmu-regulator, that control a series of multiple operons that together encode a transformasome (cellular machinery for transformation). c) the gene cl (a repressor). d) the promoter X, which includes a cl binding site (and in the absence of cl is active). e) the gene gp (encoding a green fluorescence protein). Using the cmu operon as a starting point, and assuming you can perform cloning to rearrange any of these genomic features, how would you use one or more of these to modify the…