Micro lab exercise 28, 29, 30,25
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What is the importance of catalase to certain bacteria?
Catalase protects against powerful, toxic oxidizing agents such as H2O2 (hydrogen peroxide), and super oxide which destroys bacteria cellular constitutiants.
Do most strict anaerobes produce catalase? Why does this explain why they are anaerobes?
No, most strict anaerobes cannot tolerate oxygen which is a by product of the catalase reaction
Explain the reaction how bacteria start 2O2- (superoxide) and end up with water and free oxygen, including products and enzymes used in the reaction. What constitutes a positive reaction?
- Bubbles of oxygen gas is a positve reaction
- *Look at paper for equation
What can cause a false-positive catalase reaction? Why?
Red blood cells from blood agar can be picked up when picking up a colonic (RBC's) have catalase and will give a false positive reaction
What bacteria produces coagulase and how does the enzyme function to help the bacteria survive? What constitutes a positive reaction?
- Staphylococcus Aureas
- It produces a fibrant clot around itself and avoids the attack of the host defenses. Formation of a plasma clot in the bottom of the tube is a positive test
What is being looked in the indole reaction? What constitutes a positive reaction?
Production of indole from tryptopan. Development of a pink color is a positive reaction
What is being look for in the oxidase reaction? What constitutes a positive reaction?
Indophenol oxidase oxidizes a redox dye in the reagent resulting in a color change of color from yellow to drak purple for a positive reaction
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