ID#: 15373
Caption:
These two test tubes contained the differential growth medium known as nitrate broth, used in the biochemical identification of organisms capable of reducing nitrate (NO3-) to nitrite (NO2-), or other nitrogenous compounds via the action of the enzyme nitratase, or nitrate reductase. Inside each of these tubes, was a smaller Durham fermentation tube, which had been inverted in order to catch any nitrogen gas (N2) produced as a result of the reduction of nitrate. The pink color in the tube at left indicated a positive nitrate reduction test, as well as the production of gas, while the tube at right indicated that nitrates have been completely reduced to nitrogen gas.
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Content Provider(s): CDC/ R. E. Weaver, MD, PhD
Creation Date: 1971
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