Lab Test 2 Flashcards
how do the disks inhibit growth
inhibit cell wall synthesis, DNA replication, metabolic inhibitors, protein synthesis inhibitors.
Transformation
Organism that takes up DNA, can lead to recombination, not incorporated but exists as a plasmid. Only happens if they are competent.
what bacteria was used for the UV test
Serratia marcescens. they have pigment at room temp.
gelatinase test
Look for liquefication, and the forms.
blunt needle crateriform, bulb needle napiform, thick tornado infundibular, tornado saccate, blunt tornado startiform
what is the fermentation tests for
detects fermentation of sugars, an acid reaction would turn them yellow, if it stays red it is negative. In litmus milk it is pink. Glucose, Lactose, Sucrose . Alkaline reaction = proteolysis
Starch hydrolysis test
tests for presence of amylase, positive would show a clear zone around the subject (grams iodine is used)
Casein Hydrolysis
To test a presence of caseinase, Milk plate is used, a clear zone shows.
Fermentation of sugars
Positive is yellow because the ph indicator changes it from red to yellow after for activation occurs. Phenol red is the reagent.
Litmus milk
detects fermentation of lactose. Pink is positive, negative is brown or same color, meaning an alkaline reaction occurs and proteolysis occurs.
Litmus Reduction: the culture turns white – the litmus has been reduced
Typtophan hydrolysis
detects presence of indole with kovacs reagent. Positive means red band negative is yellow brown.
MRVP
MR sees if it is a mixed acid fermenter with methyl red. VP checks if it generates acetone or ethanol/butanediol with barrits reagent.
Citrate test
checks to see if it uses citrate as a carbon source. Positive is a blue, negative a green.
Nitrate reduction
uses VP 1 and VP 2, checks to see if nitrate is present, or nitrate products, negative is red
Hydrogen sulfide production
to see if cysteine dusulfurase is present. Or what other reaction is produced, yellow is positive, red means peptone catabolized aerobically and/or anaerobically.
Urea hydrolysis
to test for urease to convert urea to ammonia and carbon dioxide
, negative is a clear orange color. A positive is pink.
