Indole Production, Hydrogen Sulfide Production And Motility Using SIM Medium Pg 85-90 Flashcards
Production of hydrogen sulfide, i dole, and motility are three tests that are combined in one differential medium called _____ medium.
SIM medium
SIM is an acronym for
Sulfide, indole, and motility.
SIM combines ingredients for how many tests? Making the agar tall a little softer to accommodate motility
3
The first test is for:
The production of hydrogen sulfide gas
The SIM medium includes ______, an amino acid, with sulfur in its R-group (1st test)
Cysteine
If the inoculated microorganism can metabolize this amino acid, ______ gas will be produced and diffuse through the medium.
Hydrogen sulfide gas
The hydrogen sulfide gas will react with ______, also in the medium, resulting in the formation of a black precipitate (_________).
-with iron sulfate
-black precipitate (iron sulfide)
(T/F)if the microorganism cannot metabolize the cysteine, no black precipitate will form
True
The second test is r the production of ______.
Indole
Some microorganisms are able to metabolize the amino acid ____, which is also in the medium, forming a product of hydrolysis called ____ which is an intermediate product of _____ metabolism.
Tryptophan
Indole
Tryptophan metabolism
How is the presence of indole indicated?
By a simple colorimetric test.
What are the intermediate products for production of indole?
Indole+pyruvic acid+ammonia
The third test is to determine ______ of the inoculated microorganism
Motility (or non-motility)
The spreading or non-spreading of growth away from the ________ within the medium will indicate motility or non motility.
Stab line
In the procedure, using aseptic technique, we stabbed one culture with _______ and ______
Escherichia coli and Citrobacter freundii
In the procedure, the talls are incubated at 37 degrees Celsius for how long?
2-4 days
In the production of hydrogen sulfide test, what did the black precipitate (Iron sulfide) indicate?
The bacteria were able to metabolize cysteine and produced H2S gas. If no black precipitate is present, cysteine was not metabolized and H2S was not produced.
In the production of indole test, the presence of indole in the medium is indicated by adding 10 drops of ________ on top of the medium
Kovac’s reagent
If indole has been produced, the kovac’s reagent will turn what color after several minutes?
Red
If indole hasn’t been produced, then the kovac’s reagent layer…
Will remain unchanged
In the motility test, what is an indication of motility?
Turbidity in all directions, well away from the stab line
