The Ology of Micros Bios: The Results Are In

Today in lab, we looked at the results from our previous tests. First up we hace the nitrate test. We took our nitrate samples out of the incubator and added 5 drops of dimethyl-a-napthylamine and 5 drops of sulfanilic acid. Since a red color appeared within the broth, this means that our bacteria tested positive for the enzyme nitrate reductase. This enzyme converts nitrate into nitrite. Next up we have the Indole results. We removed the sample from the incubation and added 5 drops of Kovac's Reagent. Since a thin layer of red appeared at the top of our tube this means bacteria 'L' does in fact break down the amino acid Tryptophan (creating Indole in the process). The Urea Hydrolysis tube was removed from the incubator and remained a yellowish color. This means bacteria 'L' tested negitive for the enzyme Urease and does not excrete ammonia. Bacteria 'L' also tested positive in the citrate utilization test! Upon removal from the incubator, it was observed that the slant of the sample turned a beautiful bright blue yet the butt remained a leafy green. This means our bacteria uses citrate as a source of energy by breaking it down with the enzyme Citrate Permease.

Today in lab we also started an Oxidase test. We added N,N,N,N tetramethyl-p-phenylenediamine to our sample in order to see if the bacteria 'L' has the enzyme Cytochrome Oxidase. Our sample turned a purple/pink immediately. This means that 'L' is positive for cytochrome oxidase which is the final electron acceptor in aerobic respiration.

We also observed the effects of the antibiotics that were performed on 'L' last lab. It turns out that 'L' was widely sensitive to Vancomycin, Chloramphenical, Erythromycin and Neomycin. (2,5,6 & 7 on the streak plate).