Micro Unknown Project!

[nursing96student]

Hi everyone,

I'm almost halfway done with my unknown project and for my next test I have to do Methyl Red. However, the last time I did this test I completely messed up.

Am I supposed to add the Methyl red dye to my culture and not the control??

[Username invalid, RN]

I'm assuming you're doing the MR-VP test, not just straight up MR. The way I did mine last semester: 2 inoculated tubes of MR-VP broth. One tube received 3-5 drops of MR. The other tube, the VP test, received 3-5 drops of Baritt's reagent.

The control in any experiment is left alone. I'm wondering what you consider to be your control?

[Neywel120]

I would definitely ask your teach or one of your classmates because they will have more insight on it.

[BubbyBoogs]

I am assuming you are using a broth for the methyl red test. You inoculate the broth with colonies from your streak plate and then incubate it. Then after 24 hours you will put 3-5 drops of the methyl red into the broth. If it is positive it should turn red, if negative it will be a wheat like color. The red indicates the fermentation of the mixed acid pathway I believe.

As far as the control goes I do not remember having one for my unknowns project. You should ask your professor.

[Aj32Cna]

I loved the unknown project. My bacteria was S. Auerous. I can't remember the details about the test though. The project is really much easier then it seems.

[OliveOyl91, BSN, RN]

My unknown bacteria was mixed in a broth with some Serratia marcescens and I was a little disappointed to discover that my bacteria was Bacillus subtillus. All I had to do was isolate my bacteria using the streak plate method and gram stain a microscope slide. Mine was the only gram positive bacilli that we worked with. I was hoping to move on to a MacConkey plate to see if it was a lactose fermenter or a mannitol salt agar to differentiate Staph. or something! Haha.