SIM Medium Determination of Sulfur Reduction Indole Producti

SIM Medium: Determination of Sulfur Reduction, Indole Production, and Motility

1.Consider the uninoculated SIM tube. a.) Is it a positive or a negative control in each test? b.)What purpose does it serve in the sulfur reduction test? c.) What purpose does it serve in the indole test? d.) What purpose does it serve in the motility test?

3. What factors dictate the choice of tests included in a combination medium?

I WOULD REALLY APPRECIATE SOME HELP WITH THESE QUESTIONS. THANKS.

Solution

1. A. This tube is a negative control because it will show no activity and thus will be able to check our positive experiment which does have inoculated media.

B. It helps us in checking the bacterial colony whether they are gram positive or gram negative. This uninocuate tube will.help.in the test by confirming that the results are authentic.

C. Indole test is used for detection of tryptophan. Microorganisms upon reavtiong with casein protein which has tryptophan results in production of indole which has its color. But in the uninoculated tube there is absence of Amy color thus we can check the presence of tryptophan.

D. Motility is checked by the presence if growth near central inoculation. Thus the tube with uninoculated media will not be able to help us in this regard. For this, we need positive control to check that the growth is of the same nature.