You are working as an intern in a research lab. Your supervisor instructs you to prepare electrocompetent cells for transformation from old batches of competent cells. The competent cells would eventually be used for both cloning purposes (to amplify your gene of interest ligated into pUC18). You found several different strains of Escherichia coli in the -80 C freezer: DH5a competent cells One Shot BL21 Star (DE3) competent cells Rosetta™ host strains BL21 competent cells Which ones would be suitable for your work? Justify your selection.

You are working as an intern in a research lab. Your supervisor instructs you to prepare electrocompetent cells for transformation from old batches of competent cells. The competent cells would eventually be used for both cloning purposes (to amplify your gene of interest ligated into pUC18). You found several different strains of Escherichia coli in the -80 C freezer: DH5a competent cells One Shot BL21 Star (DE3) competent cells Rosetta™ host strains BL21 competent cells Which ones would be suitable for your work? Justify your selection.

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter17: Bacterial And Viral Genetics

Section: Chapter Questions

Problem 1ITD

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Similar questions

For a molecular cloning experiment using the bacterial strain E. coli K12 is used to insert the gene rspL with pUC19. The first attempt utilized the restriction enzyme BamHI which did not produce any transformations. The second attempt utilized the restriction enzymes BamHI and EcoRI. Why was BamHI used first and what difference did the EcoRI do?
Austin Taylor and Edward Adelberg isolated some new strains of Hfr cells that they then used to map several genes in E. coli by using interrupted conjugation . In one experiment, they mixed cells of Hfr strain AB-312, which were xyl+ mtl+ mal+ met+ and sensitive to phage T6, with F− strain AB-531, which was xyl− mtl− mal− met− and resistant to phage T6. The cells were allowed to undergo conjugation. At regular intervals, the researchers removed a sample of cells and interrupted conjugation by killing the Hfr cells with phage T6. The F− cells, which were resistant to phage T6, survivedand were then tested for the presence of genes transferred from the Hfr strain. The results of this experiment are shown in the accompanying graph. On the basis of these data, give the order of the xyl, mtl, mal, and met genes on the bacterial chromosome and indicate the minimum distances between them.
Assume you have successfully cloned a small (200 bp) fragment of DNA into the polylinker region of a pUC18 cloning vector. Describe the appearance of transformed colonies you would expect to see on each of the following plates: plain media, media containing ampicillin, media containing tetracycline, media containing ampicillin and X-Gal.
In two isolates (one is resistant to ampicillin and theother is sensitive to ampicillin) of a new bacterium,you found that genes encoding ampicillin resistanceare being transferred into the sensitive strain. . To determine if the gene transfer involves transformation, conjugation, or transduction, you separatethe ampicillin-resistant and ampicillin-sensitivestrains by a membrane with pores that are smallerthan the size of a bacterium, but larger than thesizes of bacteriophage or DNA fragments. If genetransfer is still observed, what mechanisms arepossibly involved and which are excluded?
The first publications describing the successful production and intracellular replication of recombinant DNA appeared in the early 1970’s. Since then, there is a long list of breakthroughs achieved by recombinant DNA technology. But which one of the following are NOT on that list? Select more than one answer ifneeded. a) Recombinant Factor VIII protein for the treatment of hemophiliacs b) Positional cloning of over 100 human disease genes c) Bacteria producing human insulin for the treatment of diabetic patients d) Reproductive cloning of over a dozen humans
. In two isolates (one is resistant to ampicillin and theother is sensitive to ampicillin) of a new bacterium,you found that genes encoding ampicillin resistanceare being transferred into the sensitive strain. . To determine if the gene transfer is transformationor transduction, you treat the mixed culture of cellswith DNase. Why would this treatment distinguishbetween these two modes of gene transfer? Describethe results predicted if the gene transfer is transformation versus transduction
When using a conventional plasmid cloning vector containing a b-galactosidase gene, it is possible to perform a "blue-white screen" to determine which bacteria have taken up a plasmid into which a DNA fragment as been inserted, as opposed to those that have taken up just reclosed plasmid vector, by growing the transformed cells on nutrient agar plates containing the artificial b-gal substrate X-gal. Will bacteria that have taken up a plasmid into which a DNA fragment has been inserted form a blue colony or a white colony when grown on this medium? Briefly explain why these bacteria would form a colony of the color you chose.
In preparation for transformation, why do you think we used calcium chloride and magnesium chloride in making the cells competent? Would your results be different if monovalent ions were used instead of divalent ions? Why do you think so?
Once cloning is complete, a recombinant OXA-M290 protein can be produced in E. coli. Competent E. coli BL21(DE3) cells are transformed with the pET-28a-OXA-M290 plasmid, and the transformed cells are grown on an agar plate that contains kanamycin. The E. coli BL21(DE3) cells transformed with the pET-28a-OXA-M290 vector are next grown in liquid growth media that contains kanamycin. Once the culture reaches an OD600 of 0.6, isopropyl β-D-1-thiogalactopyranoside (IPTG) is added to a final concentration of 0.5 mM to induce protein production. How does the addition of IPTG result in the transcription of genes that are regulated by the T7 promoter in E. coli BL21(DE3) cells? [4 – 6 sentences suggested] For Context ONLY: For this biology course and based on the results obtained from a previous BLAST search, the bacteria responsible for the infection at a Hospital is most likely a new strain of Escherichia coli. This strain is given the name E. coli AFB. Earlier, BLAST was used to study a…
Suppose you wanted to study genes controlling thestructure of bacterial cell surfaces. You decide tostart by isolating bacterial mutants resistant to infection by a bacteriophage that binds to the cellsurface. The selection procedure is simple: Spreadcells from a culture of sensitive bacteria on a petriplate, expose them to a high concentration ofphages, and pick the bacterial colonies that grow.To set up the selection you could (1) spread cellsfrom a single liquid culture of sensitive bacteria onmany different plates and pick every resistant colony; or (2) start many different cultures, eachgrown from a single colony of sensitive bacteria,spread one plate from each culture, and then pick asingle mutant from each plate. Which methodwould ensure that you are isolating many independent mutations?
Austin Taylor and Edward Adelberg isolated some new strains of Hfr cells that they then used to map several genes in Escherichia coli by using interrupted conjugation. In one experiment, the researchers mixed cells of Hfr strain AB‑312, which were xyl+ mtl+ mal+ met+ and sensitive to phage T6, with F− strain AB‑531, which was xyl− mtl− mal− met− and resistant to phage T6. The cells were allowed to undergo conjugation. At regular intervals, the researchers removed a sample of cells and interrupted conjugation by killing the Hfr cells with phage T6. The F− cells, which were resistant to phage T6, survived and were then tested for the presence of genes transferred from the Hfr strain. The results of this experiment are shown in the graph. On the basis of these data, give the order of the xyl, mtl, mal, and met genes on the bacterial chromosome and the minimum distances between them in minutes. The origin of transfer is represented by the red triangle. The distances between genes are not…
A student mixes some heat-killed type IIS Streptococcus pneumoniae bacteria with live type IIR bacteria and injects the mixture into a mouse. The mouse develops pneumonia and dies. The student recovers some type IIS bacteria from the dead mouse. If this is the only experiment conducted by the student, has the student demonstrated that transformation has taken place? What other explanations might explain the presence of the type IIS bacteria in the dead mouse?