Alcanivorax is a naturally occurring oil-degrading marine bacterium that can quickly become the predominant microbe in oil-contaminated open oceans and coastal waters. To identify the genes important for the oil-degrading ability, you could attempt the following:
1) You might begin by identifying mutant Alcanivorax cells with a specific phenotype. For what mutant phenotype would you screen? Answer by completing the following statement: The mutant cells would not be able to...
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2) For your second step you might make a bacterial DNA library. What type of bacterial cells would you use as a source for the genomic DNA library?
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3) Finally, you could transform the mutant cells identified with the bacterial DNA library as given above. How would you identify cells that have a recombinant plasmid carrying a gene involved in oil degradation?
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1) The mutant cells would not be able to degrade or metabolize oil efficiently.
2) As a source for the genomic DNA library, you would use the wild-type Alcanivorax cells that have the ability to efficiently degrade oil.
3) To identify cells that have a recombinant plasmid carrying a gene involved in oil degradation, you could use a selection marker. This could be a gene that confers resistance to a specific antibiotic. Transform the mutant cells with the bacterial DNA library, and then grow the cells on a medium containing the specific antibiotic. Only cells that have taken up the recombinant plasmid will be able to grow on the selective medium, indicating that they have acquired the gene involved in oil degradation.
1) The mutant cells would not be able to degrade oil effectively.
To screen for a mutant phenotype, you would need to create a population of mutated Alcanivorax cells and then look for individuals within that population with a specific characteristic. In this case, you would want to screen for mutant cells that are unable to effectively degrade oil. One way to test this is by exposing the mutant cells to a small amount of oil and observing their growth or measuring the degradation of the oil.
2) For the second step, you would use Alcanivorax cells as the source for the genomic DNA library. A genomic DNA library is a collection of DNA fragments representing the entire genome of an organism. In this case, you want to identify the genes important for oil degradation in Alcanivorax, so you would extract the genomic DNA from Alcanivorax cells and create a library of DNA fragments.
3) To identify cells that have a recombinant plasmid carrying a gene involved in oil degradation, you would use a process called transformation. In this process, you would introduce the recombinant plasmid, which contains the gene of interest, into the mutant cells. The mutant cells would take up the plasmid DNA and some of them would become transformed with the recombinant plasmid.
To identify which cells have the recombinant plasmid, you can introduce a marker gene into the plasmid, such as a gene for antibiotic resistance. This marker gene would allow you to selectively grow only the cells that have taken up the plasmid, while the cells without the plasmid would be inhibited or killed by the antibiotic. By selecting for the presence of the marker gene, you can identify the cells that have the recombinant plasmid carrying a gene involved in oil degradation.