Citrate Utilization Test Flashcards
Some microorganisms ferment citrate when
lactic acid and glucose are not available
what are the 2 enxymes that break down citrate?What do they break down and what is oxaloacetate used for ?
- A citrate permease to allow citrate into the cell
-Citrase to breakdown citrate to oxaloacetate and acetic acid
-Oxaloacetate is further broken down to pyruvate and CO2, making the medium alkaline
Media containing bromthymol blue, a pH indicator, will become______when citrate is utilized. Media will stay_____if citrate is not utilized
Blue’
Green
Urease Test:Identifies if a microorganism uses the enzyme
urease
Urease breaks down
urea to produce ammonia, which is highly basic
Used to identify Proteus species because catalyze urea breakdown faster than many other species
urease test
what incicator does the urease test used. What color does it turn from and into
Uses phenol red to determine if ammonia has been formed
Turns PINK if solution is basic and Yellow if solution is acidic
Determines if microorganisms are able to ferment thiosulfate
Hydrogen sulfide
What does the hyrogen sulfide medium contain?
Media contains peptone and sodium thiosulfate, with FeSO4 as the H2S indicator
FeSO4 combines with H2S gas to form an insoluble black ferrous sulfide precipitate
FeSO4 combines with H2S gas to form an
insoluble black ferrous sulfide precipitate