I’m working on a microbiology writing question and need an explanation to help me understand better.
1- A 27-year old white female presented at the walking clinic of her local physician on August 15. On physical exam, the patient had a fever of 38.5C. She appeared fatigued, had tender joints, and complained of a headache, a stiff neck and a backache. The physician noticed a circular “rash” about 5 inches in diameter, with a bright red leading edge and a dim center in the form of a “bull’s eye”. The physician noted an irregular heart beat. The patient complained of lack of ability to concentrate.
The patient gave the following history: She is a graduate student in the wildlife program at the university in town. She was in the field for three weeks in Wisconsin during the months of May and June. She tracks small mammals in the field and studies their behavior. It had been a warm, wet spring and she complained of a large number of biting flies, mosquitoes and ticks in the area. She felt well until about 2 weeks after returning to her home. Since that time, many of her symptoms had progressed. She finally found that she could take it no more.
- What is your best diagnosis of this case?
- What features are critical to your diagnosis?
What further steps should be taken to clear up the problem?
2-Peptic ulcers (or stomach ulcers) are painful sores on the stomach lining. Until the 1980s, they were believed to be caused by spicy foods, stress, or a combination of both. Patients were typically advised to eat bland foods, take anti-acid medications, and avoid stress. These remedies were not particularly effective, and the condition often recurred.This all changed dramatically when the real cause of most peptic ulcerswas discovered to be a slim, corkscrew-shaped bacterium, Helicobacter pylori. This organism was identified and isolated by Barry Marshall and Robin Warren, whose discovery earned them the Nobel Prize in Medicine in 2005.The ability of H. pylori to survive the low pH of the stomach would seem to suggest that it is an extreme acidophile. As it turns out, this is not the case. In fact, H. pylori is a neutrophile. So, how does it survive in the stomach? Remarkably, H. pylori creates a microenvironment in which the pH is nearly neutral. It achieves this by producing large amounts of the enzyme urease, which breaks down urea to form NH4+ and CO2. The ammonium ion raises the pH of the immediate environment.This metabolic capability of H. pylori is the basis of an accurate, noninvasive test for infection. The patient is given a solution of urea containing radioactively labeled carbon atoms. If H. pylori is present in the stomach, it will rapidly break down the urea, producing radioactive CO2 that can be detected in the patient’s breath. Because peptic ulcers may lead to gastric cancer, patients who are determined to have H. pylori infections are treated with antibiotics.
What effect do extremes of pH have on proteins?
People who use proton pump inhibitors, also known as antacids, are more prone to infections of the gastrointestinal tract. Can you explain the observation in light of what you have learned?
3-Mutations are often considered harmful. Give an example of a mutation that would be beneficial to a microorganism. What gene would bear the mutation? How would the mutation alter the gene’s role in the cell, and what conditions would select for this mutant allele
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