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57 Cards in this Set

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  • Back
What does the
Starch Hydrolysis test
reveals whether bacteria produce the enzyme amylase, and can hydrolyze starch
What does a Positive
Starch Hydrolysis
test look like?
Postive test which produces amylase, area around the colonies will clear
What does a Negative
Starch Hydrolysis
test look like?
Negative test which amylase is not produced, the area around colonies will be blue.
How does the
Starch Hydolysis
test work?
starch reacts with iodine and turns blue. clear zone surrouding colonies indicates that the starch has been digested because acteria secreted amylase.
What does the Gelatin Hydrolysis test detect?
reveals wehether bacteria produce enzyme gelatinase and can hydrolyze gelatin.
Clinical use of Gelatin Hydrolysis test?
Staphylococcus, Enterobacteriacease, bacillus, and clostridium
What does a postive Gelatin Hydrolysis test look like?
media will turn to liquid, if gelatinase is produced
What does a negative Gelatin Hydolysis test look like?
media will be solid, if not production of gelatinase
How does the Gelatine media work?
bacteria are grown in media solidified /c nutrient gelatin in place of agar. bacteria secrete exoenzyme gelatinase the gelatin in the media will be hydrolyzed
What does Blood Agar detect?
test reveals whether bacteria produce exotoxins called hemolysins which can destroy red blook cells.
What does a positive Blood Agar test look like?
complete hemolysis, clear zone around colony - pathogenic
What does a negative Blood Agar test look like?
no hemolysis, no change in blood agar around colony - normal
What does Triple Sugar Iron test detect?
tests carbohydrate fermentation and hydrogen sulfide production
What does a positive Triple Sugar Iron test look like?
if H2S (hydrogen sulfide) produced - there will be a black precipitate in the agar
What does a negative Triple Sugar Iron test look like?
agar will not have black presence
How does TSI test work?
H2S will react with sulfar in media to produce black precipitate.
TSI is clinically used to detect for what bacteria?
What does the Thioglycollate test detect?
test reveals the oxygen requirements of bacteria.
Describe the media.
broth contains two reagents, sodium thioglycollate and L-cystein that react with oxygen,
How does the Thioglycollate test work?
resazurin that turns pink when oxygen is present
What does Indole test detect?
if bacteria are converting tryptophan into Indole, by using tryptophanase
What does a positive Indole test look like?
will be red which indicates the presence of indole - and bacteria are making tryptophanse
What does a negative Indole test look like?
no red will be present
How does the Indole test work?
incubation for 48 hours, than added few drops of Kovac's reagent, the reagent reacts with Indole to form Rsindole dye (which appears red)
Describe Indole media.
tryptophan broth also called SIM
What does MRVP detect for?
MR test reveals whether mixed acid fermentation occurs.
VP test looks at whether acetoin and 2,3-butanediol are produced
What do the different color results of the MR test look like?
Yellow: pH 6.2 - 14
Orange: 4.4 to 6.2
red: Ph 0 - 4.4
What does a positive VP test look like?
top part of medium will turn pinkish/red
Describe the medium for the MRVP test.
MRVP broth contains peptone, glucose and phosphate buffer.
What does a negative VP test look like?
Medium will turn yellowish/light brown
What does the Citrate test detect?
reveals whether bacteria can utilize citrate as the sole carbon source
What does a positive Citrate test detect?
if citrate is the carbon cource, the slant will turn blue - pH 7.6 to 14
What does a negative Citrate test detect?
will remain green - citrate is not the sole carbon source -pH 0-6.9
Describe the Citrate media.
Citrate agar contains sodium citrate, ammonium ion, Bromthymol blue as a pH indicator
How does the Citrate test work?
citrate (citic ACID) will convert ammmonia (NH3) to ammonium hydroxide (NH4OH), this will raise the pH making media more alkaline
What does the Catalase test detect?
test reveals presence of enzyme catalse
What does a positive Catalase test look like?
bubbles are present on the slide means bacteria produce catalse
What does a negative Catalase test look like?
no bubbles will appear on the slide
How does the test work?
bacteria on slide; add a drop of H2O2, if bubbles present postive test, and presence of catalase
Advantages of using light microscopy.
*easy to use
* allows live specimens
* color
Limitations of using Light Microscopy.
* can not see subatomic level
*can not penetrate molecular barrier
* not 3D, just focal plan
Advantages of X-ray Crysallography
* good 3D info on items
*shows atomic structure
*high resolution
Limitations of using X-Ray Crysallography
pain stackingly teadiesness
hard to get crystal
less accesible
can not look at live samples
Advantages of using Scanning Electon Microscopy
higher resolution then light
Limitations of using Scanning Electron Microscopy
lacks color, only b/w
samples are not alive
can not see withen the cell
Advantages of Scanning tunnineling microscopy
image individual atoms
use simple molecules
high resolution
Limitations of using Scanning Tunneling Microscopy
not live
electectly conductive
can not see whole organismWhat
What is a viable plate count?
a way to measure number or density of live cells in a liquid
What is a CFU
Colony Forming Unit; entity in milk that results in a colony on a plate
what is the formula for CFU's ml of sample?
# of colonies / dilution x volume plates (in mL)
describe the steps of doing a viable plate count.
What does ELISA stand for?
Enzyme Linked Immunosrbant Assay
What are some diseases an ELISA test, test for?
exposure to HIV, SARS, OR West Nile virus.
What does the ELISA test use to detect disease agents?
antibodies in your bodily fluid
What is an antigen?
molecule that triggers a specific immune response
What is an antibody?
Y-shaped protein in teh blood that bind specifically to an antigent and helps the body to mount an immune response against the antegent
how does ELISA test work?
1)sample incubated in plastic well. protein including antigetn sticks to plastic.
2) anti-disease primary antibodies added - if antigent present PA will seek it out and bind // then wash /c buffer
3) HRP-labeled (enzyme) 2nd. antibodie added. PA bound to antigetn, 2nd antibody will bidn to pa // wash
4) add enzyme substrate - iff antigent was present sample will turn blue