MadSci Network: Biochemistry |
Methylene blue can be used to measure respiratory activity of microorganisms. Methylene blue is a dye that will change the color of a solution depending on certain conditions. When there is oxygen present in the solution, it will be blue. When the oxygen is removed it will be colorless. Therefore, the dye can be used to determine whether microorganisms in a solution are consuming oxygen (respirating) or not. If the dye is introduced into a solution containing microorganisms, the color will begin blue. Once the microorganisms consume the oxygen by the process of respiration, the solution will become clear. The time that it takes for the solution to change colors can be used to measure the rate of respiration.
Similarly, TTC (known fully as 2,3,5-triphenyltetrazolium chloride) is a dye that is colorless in the presence of oxygen, but will turn red in the presence of microorganisms that have consumed all the available oxygen.
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