Methyl red test voges proskauer stainless steel cap

Info icon This preview shows pages 17–19. Sign up to view the full content.

View Full Document Right Arrow Icon
Methyl Red Test Voges-Proskauer Stainless Steel Cap White Plastic Cap The Methyl Red Test and the Voges-Proskauer Test are explained on the next Page. ____________________________________________________________ You make me sick with your heroics! There's a stench of death about you. You carry it in your pack like the plague. Explosives and L-pills - they go well together, don't they? And with you it's just one thing or the other: destroy a bridge or destroy yourself. This is just a game, this war! You and Colonel Nicholson, you're two of a kind, crazy with courage. For what? How to die like a gentleman... how to die by the rules - when the only important thing is how to live like a human being. © 1957 Horizon Pictures
Image of page 17

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Lab 7 Page 18 Methyl Red (Atlas Page 82) “Is this Bacterium a Mixed-Acid Fermenter?” You inoculated MGD-colored MR-VP Broth with your Gram Negative, Oxidase Negative Bacteria and incubated these Tubes at 37°C for at least 48 Hours. You will perform the Methyl Red Test on 1/2 of the Contents of each of these Tubes. • Methyl Red Positive (E. coli ) The Bacterium is a Mixed-Acid Fermenter of Glucose and produces beaucoup stable Organic Acids. This lowers the pH such that upon addition, the Methyl Red pH Indicator will remain Red. • Methyl Red Negative (Enterobacter ) The Bacterium is not a Mixed-Acid Fermenter (strongly implying that it is a Butanediol Fermenter). Very few stable Organic Acids will be produced and the pH will not be lowered enough so that the Methyl Red pH Indicator can remain Red. It will be a somewhat Red-to-Orange Color (Dried Mango). Voges-Proskauer (Atlas Page 98) “Is this Bacterium a Butanediol Fermenter?” You inoculated the MGD-colored MR-VP Broth with your Gram Negative, Oxidase Negative Bacteria and incubated these Tubes at 37°C for at least 48 Hours. You will perform the Voges-Proskauer Test on 1/2 of the Contents of each of these Tubes. • Voges-Proskauer Positive (Enterobacter ) The Bacterium is a 2,3-Butanediol Fermenter of Glucose and produces large Amounts of Acetoin and 2,3-Butanediol. The Acetion can be detected by the addition of α -Naphthol and KOH. It will be broken down to Diacetyl, which in turn will react with Guanidine in the Medium to eventually -- it can take as long as 45 Minutes! -- produce a Red Color. (Grenadine over Triple-Sec) • Voges-Proskauer Negative (E. coli ) The Bacterium in not a Butanediol Fermenter (strongly implying that it is a Mix-Acid Fermenter). Neither Acetoin nor 2,3-Butanediol will be produced. The Addition of α -Naphthol and KOH will result in no Color Change. (But since this Test takes Forever, False Negatives are a very real Issue.) NOTE: The Methyl Red and Voges-Proskauer Tests are intentionally Redundant. If a Bacterium is a Mixed-Acid Fermenter, it obviously isn’t a Butanediol Fermenter. If a Bacterium is a Butanediol Fermenter it obviously isn’t a Mixed-Acid Fermenter.
Image of page 18
Image of page 19
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern