Worksheet 9: Aero-tolerance of Microbes and the OF-Glucose Test PDF

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Aerotolerance of Microbes and the OF-Glucose Test...

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Meet Patel

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Name: __________________________

Section Number: _____________

Worksheet 9: Aerotolerance of Microbes and the OF-Glucose Test 1.

Using the illustrations below indicate where E. coli, Alcaligenes faecalis and Clostridium sporogenes grew in each tube of fluid thioglycollate broth.

C. sporogenes A. faecalis 2.

E. coli

Based on your results from the fluid thioglycollate broth, which aerotolerance category would you place each organism in?[0.75 pts]

C. sporogenes : Obligate anaerobes A. faecalis : Obligate aerobes E. coli : Facultative anaerobes

3.

Based on the results from the Anaerobic Jar exercise indicate in the table below the amount of growth (0 = no growth; 1 = minimal growth; 2 = moderate growth and 3 = abundant growth) each organism produced on the appropriate plate and the aerotolerance category of each.[0.75 pts] Growth on Aerobic Plate

Organisms Clostridium sporogenes E. coli Alcaligenes faecalis

Growth on Anaerobic Plate

Aerotolerance Cateogry

0

3

Obligate anaerobes

2

2

Facultative anaerobes

3

0

Obligate aerobes

4.

Enter your results from the Oxidation-Fermentation Glucose test, in the table below. Color Results Organism

E. coli

Pseudomonas aeruginosa

5.

Without Mineral Oil

Yellow throughout

With Mineral Oil

Yellow throughout

Yellow at the top Green throughout

Interpretation and Symbol (O, O-F, F or N)

Fermentation, Fermentation

Fermentation, No change

Michael, the absent-minded laboratory technician, made up two batches of O-F media for use in the MBIO 2815 labs. Unfortunately, when he made the first batch of media Michael forgot to add any carbohydrate to the media and when he made the second batch of media he added glucose but left out the bromothymol blue. In each case, would the test work? What effect would each of these mistakes have on the results of an O-F glucose test and why? Forgot to add any carbohydrate [0.75 pts]

No carbohrdrate in the media, thus we dont have anything to break down. So our results would look bule or green, which would give us false negative results because there was no glucose that could be broken down to produce the acidic products, so we don’t know what organism it actually is in the media.

Forgot to add the bromothymol blue[0.75 pts]

If the bromothymol blue not added to the media, the media will remain green (no change in color of the media). With only green we would get negative result, which is not the correct results. Bromothymol blue is an indicator, which means it changes the color when there is change in the pH (pH indicator). It truns blue which pH is high (alkaline), green shows neutral pH and yellow when the pH is low (acidic)....