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59 Cards in this Set

  • Front
  • Back
How do you detect amylase on a plate?
add iodine and it will turn starch purple

If clear zone, the mos made amylase
What is the degradation of starch
starch--> dextrins --> maltose --> glucose
What is used to detect lipase?
tributyrin agar if it goes from opaque to clear there is lipase
What is a clear zone on tributyrin agar called?
zone of lipolysis
What is used to detect proteinase (caseinase)?
milk agar
How can you tell if caseinase is made
if the milk agar goes from opaque to clear (clear zone surrounding colony)
What is a whitish-opaque major milk protein
What is gelatin at a temp above 25 degrees C
What is geltain at a temp below 25 degrees C
What does it mean if you chill gelatin after incubation and it is solid
there is no gelatinase (negative result)
What does it mean if you chill the medium after incubation and it is liquid?
gelatin has been hydrolized and has gelatinase (positive result)
What is rapid gelatin hydrolysis
a positive result after 2 days incubation at 37 d. C
What is slow gelatin hydrolysis
positive result after 5 d incubation at 37 d. C
What will organism degrade first: sugar or protein
What is a byproduce of sugar degradation
What is a byproduct of protein degradation
(must deaminate) base
What is the real definition of fermentation
a metabolic process in which both the electron donor and final electron acceptors are organic
What is clinical definition of fermentation
degrading the sugar including hydrolysis or any conversion of the sugar
When will mos use proteins in a medium?
when the useful CH2O is used up or absent
What are some acidic products made by carb degradation?
pyruvate, lactate, acetic acid, etc (with or without gas)
What are proteins broken down into
basic products (NH3, amines, etc)
What is incorporated into biochemical tests to detect the pH of the end products after incubation?
pH indicator
What does an acidic pH indicate
sugar fermentation/ degradation
What does a basic pH indicate
that the mos degrades proteins
What does it mean if the mos degrades proteins
it cannot use the test sugar or it has already used up all of the test sugar
What is a chemical agent that changes color in response to pH in the environment
pH indicator
What are some common pH indicators
phenol red, bromcresol purple, neutral red, bromothymol blue, litmus
Interpret a phenol red result
acid = <6.8- yellow
neutral = orange
base = >7.4- red
Interpret a bromcresol purple result
acid <6.8 yellow
base >7.4 purple
Interpret a neutral red result
acid <4.4 red
base >6.2 yellow
Interpret a bromothymol blue result
neutral= green
base = blue
Interpret a litmus result
acid <4.5 pink
neutral lavender
base >8.3 blue
Can you have gas bubbles w/o acid
no, acid makes gas
What are insoluble gases
H2 and CO2
How do you detect insoluble gases?
gas bubble in an inverted glass vial in a broth, breakage of coagulated litmus milk, breakage of solid agar
How do you detect soluble gas, such as H2S?
black ppt (FeS)
What does phenol red broth contain
peptone, pH indicator, phenol red, and a Durham tube
What sugar can be added to the phenol red broth for sugar fermentation test?
What does A in phenol red stand for?
acid production (shown by yellow color)
What does G in phenol red stand for?
gas production (gas bubble in Durham tube)
What does K stand for?
alkaline end products (indicated by red color)
What can lead to a reverse of pH in phenol red broth?
over incubation: when all the sugar is used up, the mos will start to use proteins and produce alkaline products. Broth will change from yellow to red
What is an agar slant used to different bacteria?
TSI: triple sugar iron agar
HOw does TSI differentiate bacteria
0.1% glucose
1% lactose
1% sucrose

sulfur reduction (H2S production)
What do you do in a TSI agar test?
the test mos is streaked on the slant and then stabbed into the butt
Why do bacteria grow fast on the surface of the TSI slant
aerobic condition
Why do bacteria grow slowly in the butt of the TSI slant
lack of O2
What does A in TSI test stand for?
acid production: phenol red turns yellow
What does K stand for in TSI
alkaline reaction: acid not used, protein is degraded
What does G in TSI stand for?
gas production: split the agar
What does K/K or R/R in TSI stand for?
no sugar fermentation: red slant and red butt
What does K/A or R/Y in TSI stand for?
glucose fermentation: red slant and yellow butt
What does A/A or Y/Y in TSI stand for?
lactose or sucrose fermentation (yellow slant and yellow butt)
What does H2S on TSI stand for?
H2S production: H2S + Fe++--> FeS (black ppt)
What does IMVic stand for?
MR test
Citrate test
What is used in the indole test?
tryptone broth
What is used in the MR test
MRVP broth
What is used in the VP test
MRVP broth
What is used in the citrate test
simmon citrate agar slant