BIOD 171 Lab 7: BIOD 171 Notebook :100% Verified : Guaranteed A+ Score Solution

HT07 Secondary assay for Bacterial Characterization Objective: To profile bacterial populations based on additional biochemical approaches to better determine growth/metabolic characteristics. Procedure: Indole test Biochemical test to determine a bacterial species ability to convert (breakdown) tryptophan into indole. 1. Using a sterile loop pick an isolated colony from BPA 2. Smear directly onto the reaction area of the side 3. Examine test for color change within 20 seconds a. Indole negative = yellow b. Indole positive = red/pink/orange color i. You will not always get a perfect color change so look for hues. Indole Test #2 - Liquid culture Biochemical test to determine a bacteria species ability to convert (breakdown) tryptophan into indole. 1. Using a sterile loop pick an isolated colony from a BAP 2. Inoculate bacteria in media broth 3. Grow at 37 degrees C overnight a. Note change from transparent media to cloudiness, indicating that the culture has grown 4. Add ~5 drops of Kovac’s reagent to culture a. Indole negative= yellow color, no color change b. Indole positive red/pink/orange color i. The bright pink band at the top means indole is being produced (string reaction) ii. The one on the right is still considered indole positive; not as effectively breaking down tryptophan