Chapter 6 Flashcards
What is the objective of the indole test?
To see if the MO can catabolize tryptophan
What are the products of tryptophan after tryptophanase is added?
Indole, pyruvate, and ammonia
What is the indicator in an indole test, what does it indicate, and how does it indicate?
The indicator is Kodak’s reagent which turns bright red in the presence of indole
What is the objective when using a Methyl Red and Voges-Proskaur test?
To identify different metabolic pathways used to oxidize glucose
Butylene glycol pathways produce?
Acetoin and 2,3 butaneidol
Mixed acid pathways produce?
Acidic ending products
What is the indicator of methyl red, what is it indicating, how is it indicating?
Methyl red, will turn red if there is acid
What is the indicator of the VP test, what is it indicating, how does it indicate this?
There are two indicators Barrit’s A and B and they will turn burgundy in the presence of neutral end products such as acetoin
Citrate utilization of a MO can be determined by? Why?
Using a Simmons citrate medium because it is selective
Why does the Simon citrate media change color with MO growth?
If the MO can utilize citrate it will also create a byproduct of ammonia which will cause the media to be more basic due to the presence of bromothylmol blue in solution
What color is the positive and negative test of citrate utilization?
Positive is dark blue
Negative is green
What is the positive and negative of all the IMViC test
Indole: + is red, - is original color of solution (clear)
Methyl Red: + is red, - is original color of solution (clear)
VP: + is burgundy, - is original color of solution (clear)
Citrate: + is blue, - is green
What is Ecoli positive for?
indole and methyl red
What is E. Aerogenes?
VP and citrate
Why does adding hydrogen peroxide to a MO cause bubbles if it has catalase?
Because when catalase changed H202 into water it also produced oxygen gas
What is cytochrome oxidase?
The final electron acceptor in a ETC
How do we test for cytochrome oxidase?
We add a test oxidase reagent and observe to see if a purple compound forms (when in the presence of O2)
What is wurster’s blue
A purple colored complex made up of chytochrome C, O2, and Test Oxidase reagent
The EMB plate is selective and differential. T or F?
T
What is the EMB selective for?
gram negative lactose fermenting non pathogenic MO
What is the differential aspect of an EMB plate
There are dyes that react with acidic products which will be produced by colonies that ferment
Luisetti’s media is selective and differential. T or F?
T
Lusetti’s medium detects the presence of _____________
Fluorescein
How do we test for motility, what is the indicator?
We test for motility by using in TTC, when it is oxidized it is clear but when it is taken up by the cell and reduced it is red
Why can non motile MO still be observed to be “moving”?
Due to the Brownian Motion
What is the difference between methyl red and phenol red?
Methyl red is an indicator of acid (red when acidic, yellow when basic)
Phenol red is an indicator of base (red when basic, yellow when acidic)
________________: has components that inhibit growth of certain MO allowing others to grow better
Selective media
_______________: allows all MO to grow but they have components that allow you to istinguish between certain groups of microbes
Differential media
