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Why is there a colored band at the surface of fluid thioglycollate medium which is more desirable a thick or thin colored band?
The higher viscosity of the Fluid Thioglycollate Medium prevents rapid uptake of oxygen and helps maintain the stratification of organisms growing in different layers of the broth.
Oxygen is driven out of the broth by autoclaving, but as the broths sit at room temperature, oxygen begins to diffuse back into the tube. Any increase in the oxygen content is indicated by the redox indicator sodium resazurin which changes its color to red.
Obligate aerobes will only grow in this oxygen-rich top layer. Obligate anaerobes will only grow in the lower areas of the tube. Microaerophiles will grow in a thin layer below the richly-oxygenated layer. Facultative or aerotolerant anaerobes can grow throughout the medium but will primarily grow in the middle of the tube, between the oxygen-rich and oxygen-free zones.
What else can I help you with?
What does a blue or pink color in thioglycollate mean?
A blue color in thioglycollate indicates the presence of oxygen in the growth medium, as oxygenated environments turn the indicator dye blue. In contrast, a pink color signifies that the medium is anaerobic, as the dye is reduced in the absence of oxygen, turning pink.
How can you tell if thioglycollate medium is prepared correctly?
Thioglycollate medium should be clear and have a slightly amber color. There should be no precipitates or cloudiness. Additionally, performing a sterility test before use can confirm if the medium was prepared correctly.
Can a strict aerobe be distinguished from an anaerobe in thioglycollate broth?
Yes. Thioglycollate is a reducing medium that can establish a gradiation in oxygen content. Oxygen is highest at the top of the tube and absent in the deeper regions.Source: "Foundations in Microbiology" by Kathleen Park Talaro.
Why use fresh thioglycollate medium?
A fluid thioglycollate is preferably used soon after preparation to minimize the amount of oxygen that is permitted to diffuse towards the bottom of the medium. The longer you wait before using this medium, the more oxygen is allowed to diffuse into it; more oxygen will negatively affect the growth of obligate anaerobes but would positively affect the growth of aerobic organisms.
What chemical type is thioglycollate broth?
Thioglycollate broth is a reducing medium used primarily for the cultivation of anaerobic bacteria. It contains sodium thioglycollate, which acts as a reducing agent to create a low-oxygen environment, facilitating the growth of anaerobes. The broth also contains nutrients such as peptones and glucose to support microbial growth. Additionally, it is often supplemented with resazurin, a dye that indicates the presence of oxygen by changing color.
Is a thick band or thin band more desirable at the surface of Fluid Thioglycollate?
A thin band is generally more desirable at the surface of Fluid Thioglycollate medium, as it indicates a higher concentration of aerobic organisms that are more likely to grow in oxygen-rich conditions. A thick band may suggest overgrowth or contamination, which can complicate the interpretation of microbial growth. The thin band allows for clearer differentiation of microbial growth patterns and better assessment of the organisms present.
The properties and purposes of thioglycollate medium?
Thioglycollate medium is a liquid medium used to culture anaerobic bacteria, capable of reducing oxygen molecules in the medium. It contains cystine and resazurin as oxygen indicators. Thioglycollate medium supports the growth of a wide range of microorganisms, making it suitable for various applications such as sterility testing and isolation of anaerobes.
What does a blue or pink color in thioglycollate mean?
A blue color in thioglycollate indicates the presence of oxygen in the growth medium, as oxygenated environments turn the indicator dye blue. In contrast, a pink color signifies that the medium is anaerobic, as the dye is reduced in the absence of oxygen, turning pink.
How can you tell if thioglycollate medium is prepared correctly?
Thioglycollate medium should be clear and have a slightly amber color. There should be no precipitates or cloudiness. Additionally, performing a sterility test before use can confirm if the medium was prepared correctly.
What is the function of thiogllycollic acid in thioglycollate?
It removes trapped oxygen from the medium
Can a strict aerobe be distinguished from an anaerobe in thioglycollate broth?
Yes. Thioglycollate is a reducing medium that can establish a gradiation in oxygen content. Oxygen is highest at the top of the tube and absent in the deeper regions.Source: "Foundations in Microbiology" by Kathleen Park Talaro.
Why use fresh thioglycollate medium?
A fluid thioglycollate is preferably used soon after preparation to minimize the amount of oxygen that is permitted to diffuse towards the bottom of the medium. The longer you wait before using this medium, the more oxygen is allowed to diffuse into it; more oxygen will negatively affect the growth of obligate anaerobes but would positively affect the growth of aerobic organisms.
Why you use Fluid Thioglycollate medium for bacterial contamination checking?
Fluid Thioglycollate is a medium used to grow and observe all manner of aerotolerance in bacteria. Therefore if you were to place a sample in it to see if it contained bacteria or not, given the correct temperature needed, the bacteria would be able to be observed fairly quickly as they would grow exponentially in this nutrient rich environment.
What chemical type is thioglycollate broth?
Thioglycollate broth is a reducing medium used primarily for the cultivation of anaerobic bacteria. It contains sodium thioglycollate, which acts as a reducing agent to create a low-oxygen environment, facilitating the growth of anaerobes. The broth also contains nutrients such as peptones and glucose to support microbial growth. Additionally, it is often supplemented with resazurin, a dye that indicates the presence of oxygen by changing color.
Why will obligate anaerobes grow in thioglycollate?
Obligate anaerobes do not need or use oxygen as a nutrient. In fact it is a toxic substance to them which either kills or inhibits their growth. Thioglycollate allows obligate anaerobes to grow because it consists of sodium thioglycollate, thioglycollic acid and L-crystine which reduce oxygen to water. This creates an anaerobic environment allowing obligate anaerobes to grow.
Why is sodium thioglycollate used in lab media?
Sodium thioglycollate is used in lab media to reduce the oxygen content in the medium, creating an anaerobic environment. This is useful for growing and studying anaerobic bacteria that cannot survive in the presence of oxygen. Sodium thioglycollate helps to maintain anaerobiosis by chemically binding to oxygen.
Where would you expect to see growth of a strict aerobe anaerobe microphile and facultative anaerobe in the fluid thioglycollate medium?
The sodium thioglycollate in the broth creates a redox potential in the tube, with higher levels of oxygen at the top of the tube, and a complete absence of oxygen at the bottom of the tube.Fluid thioglycollate broth also typically contains a redox potential indicator such resazurin, which produces a pink color in an oxidized environment. As with the BHI media, organisms will only be able to grow where their oxygen requirements are met, and will localize to the area(s) of their oxygen requirements in the fluid thioglycollate broth.Obligate aerobes will grown on or very close to the top (high oxygen). Obligate anaerobes will only grow on the bottom (no oxygen). Facultative anaerobes will grow throughout but more on top. Microaerophiles will be found in a band where only a small amount of oxygen is found. They would be close to but not on the top.
