You isolated two bacteria from soil that you assumed were different species since they have different properties - for example, one is resistant to several antibiotics and the other is not. However, upon sequencing the 16S rRNA genes of the isolates, you have discovered that they are the same genus and species. When you extract the total DNA from each and run a gel, you discover the resistant strain has a plasmid in addition to the primary Chromosome. a. How might this strain have acquired the plasmid? b. What is definitely encoded on the plasmid given the information provided? c. How could you use fluorescence microscopy to determine if other bacteria in your soil suspension are carrying the same plasmid? Be sure to comment on the type of fluorescent probe, how it will interact with your sample, and how you will distinguish cells harboring the plasmid from the rest of the population (what will it look like).

In transformation, a bacterial cell takes up DNA fragments from its surroundings. The figure shows the process of natural transformation. Position the labels below with the correct images. (A) Donor and recipient genomes The donor strand is integrated into the recipient chromosome and the displaced bacterial DNA is degraded. A wild-type donor cell is in the vicinity of a double auxotroph. If the wild-type cell lyses, it releases DNA into the environment. One cell is identical to the original recipient, while the other carries the wild-type genes. A competent recipient cells a receptor site on its surface. One strand of donor DNA enters the cell and pairs with a homologous region of the bacterial chromosome The remaining DNA strand is degraded. A donor DNA strand binds to the receptor site. Reset trpC1 Wild-type donor cell Mechanism of natural transformation Donor DNA hal Receptor site- trpc/his double auxotroph Recipient cell Competent cell recipient -Bacterial chromosome (had.bpC") Ma…

Examine the structure of the pBR322 plasmid depicted below. Assume total size of the plasmid is 4,361 bp and the blue numbers indicate locations of restriction sites relative to the O point at the top of the plasmid. What size fragments would be generated by the following restriction digestion reactions? 1. Sall 2. Sal 1 + BamH1 3. Sal 1 + EcoR1 4. Sal I + BamH1 + EcoR1 PstI 3607 3000 4000 amp ori HindIII Edit View Insert Format Tools Table EcoRI EcoRV 4359 0 29 185 pBR322 4361 bp 2295 NdeI tet 2000 BamHI 375 651 SalI 1000 Type a short answer in the space provided below.

a) If lacZ was successfully inserted into the plasmid and E. coli successfully transformed, then the lacZ gene will be expressed which will breakdown X-gal producing a blue-colored colony. b) If the gene of interest was successfully inserted into the plasmid and E. coli successfully transformed, then the LacZ gene will not be expressed so X-gal will be broken down leading to a blue-colored colony. c) If the gene of interest was successfully inserted into the plasmid and E. coli successfully transformed, then the LacZ gene will not be expressed so X-gal will not be broken down leading to a white-colored colony. d) If lacZ was successfully inserted into the plasmid and E. coli successfully transformed, then the lacZ gene will be expressed which will breakdown X-gal producing a white-colored colony.

The mutation for drug resistance in Mycobacterium tuberculosis, the bacteria that causes the disease tuberculosis, occurs within the chromosome, not in the plasmid. How do you think this would affect the likelihood of an individual bacterium becoming drug resistant?

On the gel diagram below, show how you believe these fragments will sort out during electrophoresis. Label each fragment with its correct number of base pairs. (8 fragments)