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The purpose of the thio-glycolate broth, which, if memory serves, is a semi-solid agar, is to determine oxygen requirements. E. coli is a facultative anaerobe which means it prefers aerobic conditions but can grow (to a lesser extent) anaerobically. So you will see growth at the top of the thio-glycolate tube mainly where there is oxygen, perhaps some just along the shallow stab line from inoculation. It will not permeate throughout the medium since it prefers aerobic respiration and oxygen is available at the top.
What else can I help you with?
Why doesnt the oxygen that diffuse into the thioglycolate broth inhibit the growth of anaerobic organisms?
Oxygen diffusing into the thioglycolate broth gets consumed by the chemical reaction between the thioglycolate and the oxygen. This reaction forms a gradient of oxygen concentration within the medium, creating an oxygen-free environment at the bottom of the tube where anaerobic organisms can grow.
Why is thioglycolate broth stored at room temperature?
Thioglycolate broth is stored at room temperature because it contains a reducing agent (thioglycolate) that helps to maintain anaerobic conditions by removing oxygen from the medium. Storing it at room temperature helps to maintain the integrity of the reducing agent and promote the growth of anaerobic bacteria. Refrigeration can cause the reducing agent to crystallize, making it less effective.
Why is nutrient broth better than peptone broth?
Nutrient broth contains a wider range of nutrients, such as meat extract and yeast extract, making it more suitable for supporting the growth of a variety of microorganisms. Peptone broth, on the other hand, primarily provides amino acids and peptides, which may limit the types of microorganisms that can grow in it.
What is thioglycolate broth?
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
Does Bacillus subtilis grow in MacConkey broth?
Bacillus subtilis is grown on nutrient agar or in nutrient broth. The preferred medium is M9 with glucose.
Is it necessary to cook the nutrient broth?
To destroy any competitors for the broth, fungi and bacteria.
What are the essential ingredients of a carbohydrate broth?
nutrient broth + 0.5% particular carbohydrate + indicator
Is nutrient broth suitable for the growth of fungal species?
NO
Why does nutrient broth go cloudy?
Nutrient broth can go cloudy due to the growth of bacteria or other microorganisms in the broth that cause a change in its appearance. The cloudiness may also be a result of the formation of bacterial colonies or biofilms within the broth.
What would be a nitrogen source for the nutrient broth or agar?
the east extract is the main source of nitrogen in the nutrient broth or agar
Do you expect turbidity in the unsterilized nutrient broth that was incubated?
Yes, turbidity is expected in unsterilized nutrient broth that was incubated, as the presence of microbial growth will cause the broth to become cloudy due to the increase in cell density. The turbidity is a visible indicator of microbial growth in the broth.
What is the composition of a nutrient broth and how does nutrient agar differ from nutrient broth?
Nutrient agarPeptone - 5 g/LMeat extract - 1 g/LYeast extract - 2 g/LSodium chloride - 5 g/LAgar - 15 g/LpH - 7.0 ± 0.2Storage temperature - 2-8°CNutrient broth is a liquid formulation that does not contain agarNutrient Borth are used for enrihment of specified bateria like E,coli and salmnella
