Lab Exercise 46 PDF

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Lab Report 46 Name: __Michele Glantz__ Date: ___6/13/19_______

Urease Your Results and Observations Record your results after incubation in the table. You may also wish to photograph your tubes.

Organism Proteus vulgaris Excherichia coli

Results (color) Pink Yellow

Does this organism produce Urease? Yes (+) No (-)

Interpretation and Questions 1. Why is it important to limit the available types of nutrients in this broth? Limiting the nutrients to urea as the primary source of carbon ensures that only urease-positive organisms will grow in the medium. 2. The case file gives an example of a digestive system infection caused by a urease-positive organism. What other system or systems could commonly be colonized by urease-positive bacteria? Why? The Urinary System. Urea is a by-product of amino acid catabolism in animals and comprises the principal nitrogenous waste product in urine. 3. Urea broth indirectly identified urease activity by the change in medium pH. How else could urease activity be monitored (consider the case file and the enzyme reaction pathway shown by the equation)? Urease can be monitored using radio-labeled urea, which is then converted into radio-labeled carbon after the organism hydrolyzes the urea. 4. You are testing an unknown organism from an infected patient. Your urease tube shows a slow urease reaction. Additional testing shows that the organism is positive for glucose and lactose fermentation, and negative for indole. Using the table in exercise 49 (49.2), what is the organism? Klebsiella pneumoniae. 5. Consider the case file. Helicobacter pylori metabolizes urea and releases ammonia. How would this affect the microenvironment of the stomach? Is this an important consideration in the treatment of stomach ulcers? Why or why not? H. pylori produces a urease to convert urea from gastric juices as well as saliva into bicarbonate and ammonia—thus, the microenvironment directly surrounding the bacterium is neutralized and the pathogen escapes the corrosive effects of the gastric secretions. Yes if this consideration can be utilized in the way which can stop the bacteria in utilizing the urease, then it would be a breakthrough in controlling ulcers caused by this bacteria.

Lab Report 46...