What is thioglycolate broth?

Answer 1

Thioglycolate (thio) broth contains Sodium thioglycolate, a reducing agent that creates anaerobic conditions when it reduces molecular oxygen to water. Dyes such as resazurin or methylene blue are usually added to the broth to provide a visual indication of the presence of oxygen. Resazurin is pink when oxidized and colorless when reduced. Methylene blue is blue when oxidized and colorless when reduced. The pink band near the top of the broth results when oxygen diffuses in. Strict aerobes will grow only in the pink band, microaerophiles will grow near the bottom of the band where the concentration of oxygen is lower. The absence of pink in the rest of the tube indicates the absence of oxygen and a suitable environment for strict anaerobes. Both facultative anaerobes and aerotolerant anaerobes will grow throughout the tube; however, facultative anaerobes will grow most densely where oxygen is present. Other constituents:L-Cysteine Yeast Extract Glucose Agar(may be or not) Peptone Distilled Water. *The use of thioglycolate broth permits growth of anaerobic bacteria. In addition, growth patterns can help distinguish aerotolerance of bacteria. E.g., Clostridium sporogenes, Clostridium perfringens. PROCEDURE Step 1. Label 2 Blood Agar plates, one plate will be titled "Aerobic" and the other titled"Anaerobic". Step 2. Using your inoculating loop, streak each plate with Clostridium perfringens. Step 3. Place the anaerobic Blood Agar plate in a Bio-Bag or Gas Pac Jar. The instructor will demonstrate proper set up of the environmental chamber. Step 4. Incubate both plates at 37C for 24-48 hours. Step 5. Obtain Three Thioglycolate Broth tubes -DO NOT SHAKE THESE TUBES!. Gently label each Thioglycolate Broth with one of the assigned species being careful not to tip the tube horizontally . Step 6. Using your inoculating loop, inoculate each Thioglycolate Broth with it's assigned species. Step 7. Incubate the Thioglycolate Broth at 37C for 24-48 hours. Note: Procedure taken fromhttp://bioweb.wku.edu/courses/Biol208/Lab_Manual/208%20week%2011.pdf.Dr.Ank