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Explore This Topic

Check Your Understanding

The following questions accompany this lesson. The answers are given below each question. To reveal an answer, place the cursor over "REVEAL THE ANSWER".

1. Why is it important to study proteins and protein interactions?
   

2. Give three examples of processes and structures in bacteria that are targeted by antibiotics.
   

3. Explore this web page and answer the following questions:

   During what war were antibiotics first used?
   

   What proteins are Merck Laboratories targeting to overcome antibiotic resistance?
   

4. What does Gram-positive bacteria mean?
   

5. Which type, Gram-positive or Gram-negative, is resistant to penicillin?
   

6. What is the difference between Gram-positive and Gram-negative bacteria that causes one to be resistant to penicillin?
   

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Exercise Your Brain

Research

Choose a disease and work with a partner to research what is known about the cause of that disease. (Review this list of diseases at Wikipedia to get started.) Invent some possible treatment strategies for the disease. What could be potential targets for a drug and why? Be prepared to give a brief presentation to your classmates about the disease and the treatment strategies you have come up with.

Case Study: What Is It and Where Did He Get It?

Anglers Suspect Water After Staph Infections
October 31, 2003, By Candace Rondeaux, St. Petersburg Times

“Brent Perrine was one of three Tarpon Springs sponge divers who recently reported having a painful skin condition thought to be caused by a methicillin-resistant Staphylococcus aureus infection. Commonly known as MRSA, the drug-resistant strain of bacteria was also found in at least 10 fishermen in Port Orange in Volusia County in recent months.”

“I've been diving for almost 20 years, and I've never seen water like that," Perrine said. "It was all yellow.”

“Bob Jones, executive director of the Southeastern Fisheries Association, a statewide fishing industry group, asked Gov. Jeb Bush for help after receiving dozens of reports about fishermen who had recently contracted Staphylococcus aureus. If left untreated, it can also cause life-threatening blood infections.”

“Widespread fears that the water is the source of fishermen's illness is probably an overreaction, state health officials say. Staph infections are common, and it is not likely that recent cases represent an outbreak among commercial fishermen.”

“Staph infections occur most often in places where people are confined to close quarters, such as a prison or hospital or even a cramped fishing vessel.”

A fisherman off the coast of California who had been having diarrhea read the article. He went to the doctor and they took a urine sample to find out what he had.

Find out the results of his test and do the following:

1. Click on bacterial identification lab.

2. Click to enter the lab (or click to Start Over). Do the virtual lab by following instructions on the screen. (Be sure to read the notebook information displayed down the right side of the screen.) Click on all the sections of the lab in this order:

   • Sample Prep
     
   • PCR Amplification
     
   • PCR Purification
     
   • Sequencing Prep
     
   • DNA Sequencing

3. Click on Sequence Analysis.

4. Click on Samples on the upper right of the screen. Select Sample C.

5. Click the Start button in the center of the picture of the lab. Follow the directions in the notebook information displayed down the right side of the screen. Numbers 6 through 12 below will guide you through this.

6. Click the link in Step 1 on the screen. This will display the DNA sequence produced from your bacteria sample. Select all of the sequence--don’t leave any bases out. Copy this sequence.

7. Click the link in Step 2 on the screen. Paste your copy of the sequence in the search window. You will now search an actual database just like researchers do to see what matches the sequence from your bacterial sample.

8. Click Blast. You don’t have to fill in any other boxes.

9. Click Format on the new page that appears. A new page appears with the information about which sequences in the database matched yours. Sequences from other bacteria may have matched some part of your sequence but the best match is at the top of the list labeled: Sequences producing significant alignments.

   To the right of the blue letters and numbers is the scientific name of a bacterial species. That is the one that matched best.

10. Click back on the screen showing the lab with a computer.

11. Click the computer screen in the lab on that page. A list of bacterial species appears.

12. Click the one that aligned best with your sequence. If you got the right one it will tell you that. It will show the name of the bacteria in the sample as a hot link. That link will give you important information for answering the questions below.

Questions

1. What bacterial species does your data suggest is causing the fisherman’s symptoms?

2. Can you be sure this is causing his symptoms or might there be something else contributing?

3. Do the bacteria that your test came up with cause the symptoms he was having? (Click on the name of your bacterium in the information column to the right of the lab screen to find that information. It should still be displaying Sample information and if you got the answer correct it will have the name of the correct bacteria in bold as a hot link.)

   Get more information on this bacterial species.

4. How could you find out what was causing his problem if it is not this bacterial species?

   Perform another lab for Sample B. Then answer the following:

5. Where might the fisherman have been exposed to the bacteria that are causing his diarrhea?

6. Would either of these bacteria be treated with penicillin? Review Gram-negative and Gram-positive bacteria.

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