Applying the Methyl Red (MR) Test

The final test was a gelatin test. Gelatin medium consists of gelatin, peptone and beef extract (Stout et al., 44). For gelatin testing, perforation techniques were used to inoculate gelatin medium. I sterilized the pierced device under direct fire, got a small amount of unknown bacteria and pierced the gelatin medium. After inoculation with gelatin medium, it was incubated in a hot chamber at 37 ° C. for 8 days. After 8 days of incubation, the gelatin medium was placed in a "cold chamber" at 4 ° C. for 1 hour.

IMVIC test: This biochemical test using aseptic technique consists of "哚", methyl red, Voges-Proskauer and Simmons-citrate. (Hurley, 156) The methyl red (MR) part tested was to check whether the bacteria were a mixed acid fermentor or a butane diol fermenter. Part of the Voges - Proskauer (VP) test is to check if bacteria are fermenting glucose. The citrate part of the trial tried to clarify "whether bacteria can use citrate as the sole carbon source for their energy needs." (Harley, 157) If you pass the MR test and it is positive, red will remain or be strengthened. If it is minus it gets red. If a color other than water yellow appears, the VP test is positive. If the color does not change, VP is negative. If dark blue is displayed, the citrate test is positive. If the color remains green it is negative.

If citrate is positive, bacteria are Enterococcus or Citrobacter. The test that distinguishes the two is methyl red - "Voges Proskaer medium. MR-VP is used to distinguish bacteria based on the ability of glucose hydrolysis and to produce stable organic acids during fermentation. When drugs are added to the medium, the positive result of the methyl red test turns red and the positive result of the Voges Proskauer test turns red.

I took the original broth, used it for the methyl red test, and added 2 to 5 drops of methyl red indicator. Move broth and MR for several minutes and mix it, it becomes red. This indicates that it is methyl red positive, which means it is positive for acidic pH. Approximately 10 drops of VPA and 10 drops of VPB reagent were added to the broth. After shaking the broth and VPA and VPB for about 20 minutes, it did not appear to emit a cloudy yellow rather than a red color, indicating that this organism is negative for VP. The final test of the IMIV test is the citrate test.

D = Pseudomonas species. A Methyl Red assay can be used to further confirm that Sample D is a Pseudomonas species. The Methyl Red test is a test to detect the production of sufficient acid during glucose fermentation and the conditions such that the pH of the previous culture remains below 5, as indicated by the change in color of methyl red maintain. Indicators were added at the end of the incubation period. The results of this test on Pseudomonas sp. Were negative as there was no color change when adding Methyl Red. The color remains yellow (online microbiology note, 2014a)