You have three bacterial strains: one is resistant to kanamycin (strain A), another is resistant to gentamycin (strain B), and a third is not resistant to either antibiotic, but produces a purple pigment (strain C). (A) Suppose the antibiotic resistance of one strain is due to a gene on the chromosome, whereas the resistance of the other is due to a gene on a conjugative plasmid. Describe how you could determine which antibiotic resistance is plasmid encoded. (B) Describe how you could determine which, if any, of the strains are naturally competent (i.e., able to take up DNA by transformation).

answer

watching

212

views

For unlimited access to Homework Help, a Homework+ subscription is required.

You have 0 free answers left.
Get unlimited access to 3.8 million step-by-step answers.

Get unlimited access

Already have an account? Log in

Sixta KovacekLv2

23 Jul 2018

Unlock all answers

Get 1 free homework help answer.

Already have an account? Log in

Related questions

Dr. Bimmel is concerned about eliminating the carrier state of S. pneumoniae. She is particularly concerned about finding ways to prevent S. pneumoniae-caused otitis media without the use of antibiotics. Antibiotic use against S. pneumoniae has become problematic. Amoxicillin worked for her as a child, but today there are many antibiotic resistant strains.

a. Describe how amoxicillin affects bacterial cells. (What is the target site? What does amoxicillin do?)

b. What is the gene product of the blaA gene?

c. How does this gene product allow bacteria to survive exposure to amoxicillin?

d. Does blaA confer resistance to antibiotics other than amoxicillin (like tetracycline and kanamycin)? Briefly explain

e. Show (describe) how the blaA gene could be naturally transferred from a S. pneumoniae cell that is amoxicillin resistant to a S. pneumoniae strain that is susceptible to amoxicillin. Include in your response a description of the selection conditions required to select for amoxicillin-resistant S. pneumoniae.

f. Is this a genotypic change? Design an experiment to support your answer.

A kanamycin-resistant, ampicillin-resistance plasmid (3 kb) is cleaved with the PstI enzyme, which cuts within the ampicllin resistance gene. The digested plasmid is ligated to a 5-kb PstI DNA fragment from Drosophila (fruit fly). The DNA mixture was then transformed into E.coli host cells.

(i). Which antibiotic would you put into the medium (nutrient agar plate) to select for cells that contain the plasmid?

(ii). Explain step by step, how you would select for cells containing the recombinant Drosophila DNA.

(iii) If different colonies from the plate in part (ii) are cultured in nutrient broth and DNA was isolated from each of the bacterial cultures, what restriction patterns would you expect to see following PstI digestion and agarose gel electrophoresis?

jadehound73

Using the table below, explain the purpose of each of the steps of the Experimental Flow Diagram (Figure 1 from your lab manual) for answering the two research questions guiding this laboratory investigation:

Is the bacterial contamination at the three farms due to the same plasmid or different plasmids?

What is the frequency of antibiotic resistant bacteria in the farm cultures?

Box	Why are you doing this step?	How is this step relevant to research question(s) 1 and/or 2?
Week 1: Experiment Part A
Week 2: Experiment Part B
Week 2: Experiment Part C
Week 2: Experiment Part D
Week 3: Calculate frequency of antibiotic resistance at farms
Week 3: Use size markers on gel to determine size of resistance genes
Week 3: Compare size to known size of resistance genes to identify which gene was present in each farm