Question | Answer |
what is the products formed from sugar fermentation test? | Acid with or without gas |
what is a positive result of sugar fermentation test? | red indicator turns yellow |
what is the purpose of sugar fermentation test? | production of acid and/or gas in fermintation |
what are possible mediums for sugar fermentation? | phenol red glucose broth, phenol red lactose broth or phenol red mannitol broth |
what is a negative result of sugar fermentation test? | red indicator remains red |
what is a negative result of Methyl Red test? | Broth remains yellowish/orange or has no color |
what is a negative result of Voges-Proskauer test? | Broth turns a dark brown/green color |
what is a negative result of Catalase test? | no bubbles visible |
what is a negative result of Oxidase test? | no color change within 30 sec |
what is a negative result of Starch Hydrolysis test? | no clear zone (entire plate is dark blue) |
what is a negative result of Gelatin Hydrolysis test? | no liquefaction of medium |
what is a negative result of Indole Production test (Tryptophen Hydrolysis)? | Yellow layer on the top of the culture |
what is a negative result of Urease test? | no color change to medium (yellow-orange) |
what is a negative result of H2S test? | no black precipitate (possible red/yellow change) |
what is a negative result of Citrate Utilization test? | Medium is unchanged, lite green color |
what is a negative result of Litmus Milk Reaction Coagulation test (Curd)? | Medium is unchanged |
what is a negative result of Litmus Milk Reaction Peptonization test (Casein Hydrolysis)? | Medium is unchanged |
what is a negative result of Litmus Milk Reaction Litmus Reduction test? | Medium is unchanged |
what is a negative result of Litmus Milk Reaction pH change test? | Medium is unchanged |
what is a positive result of Litmus Milk Reaction pH change test? | acid = PINK alkaline= PURPLE |
what is a positive result of Litmus Milk Reaction Litmus Reduction test? | litmus changed to WHITE (changed by oxygen being used up) |
what is a positive result of Litmus Milk Reaction Peptonization test (Casein Hydrolysis)? | becomes Transparent (due to hydrolysis of casein) |
what is a positive result of Litmus Milk Reaction Coagulation test (Curd)? | Curd formation, whay liquid maybe presence on surface |
what is a positive result of Citrate Utilization test? | medium will turn Prussian BLUE |
what is a positive result of H2S test? | Black precipitate formed (iron sulfide) |
what is a positive result of Urease test? | medium turns HOT PINK |
what is a positive result of Indole Production test (Tryptophen Hydrolysis)? | red layer on the top of the culture |
what is a positive result of Gelatin Hydrolysis test? | liquefaction of medium |
what is a positive result of starch hydrolysis test? | a clear zone next to bacterial growth |
what is a positive result of oxidase test ? | organism turns PURPLE |
what is a positive result of catalase test ? | bubbles visible (immediate) |
what is a positive result of Voges-Proskauer test? | Broth turns RED |
what is a positive result of Methyl Red Test ? | Broth turns PINK/RED |
2 tests can be performed on MRVP Broth, what are those tests? | 1. Methyl Red (test for LOTS of ACID) 2. Voges-Proskauer (acetoin production, 2-3 Butanediol Fermentation) |
The Methyl Red and Voges-Proskauer tests both use what same Medium? | MRVP Broth |
Methyl Red Test:Name of MEDIUM? | MR-VP Broth |
Methyl Red Test:Important INGREDIENTS in Medium? | 1 carbohydrate (glucose, lactose, or sucrose), peptone, phenol red indicator and Durham tube (only in glucose tube) |
Methyl Red Test:How to INOCULATE? | Loop inoculate broth |
Methyl Red Test:How to INCUBATE Medium for Test? | incubate at 35°C for 48 hours |
How do you perform the Methyl Red test? | 1. After incubation, transfer 1 mL of broth into a NEW sterile TUBE
2. Add 4-5 drops of Methyl Red
3. Read color results |
How do you interpret the Methyl Red test RESULTS? | Methyl Red colors:
(+) RED pH<= 4.4
(-) YELLOW pH = 6.2
(-) NO COLOR CHANGE (no mixed acid fermentation) |
T/F ==CHEMICAL==If bacteria CAN do MIXED ACID FERMENTATION, acid BYPRODUCTS will OVERCOME PHOSPHATE BUFFER (LOWERS pH), ELSE pH REMAIN SAME | True |
T/F ==METABOLIC==Fermentation is a metabolic process in which ORGANIC MOLECULES act as ELECTRON DONOR (OXIDIZED) and 1 or more ORGANIC PRODUCTS act as FINAL ELECTRON ACCEPTOR. | True |
T/F Usually if (+) for Methyl Red test, then (-) for Voges-Proskauer cuz look for different acids | True |
1 pH CHANGE is A LOT. By what FACTOR is this? Also how many more times acidic is a change from 6 pH to 4 pH? | 1 pH change = 10 times
6 to 4 pH is a 100 times more acidic |
How to read results of Indole? | After adding Kovac's: red layer on top -> positive for Indole -> Trytophanase hydrolyzes tryptophan
Yellow layer on top-> Indole negative -> Tryptophanase absent. |
Blackening of the medium?? | H2S is produced. |
How to read methyl red test? | After adding methyl red: : MR positive= turn red (pH 4.0)
MR negative= turn to any other color (pH 6.0 or higher) |
How to read Voges Proskauer test? | After adding Reagent A and B: : VP postitive=Turn red ->Acetoin
VP negative=If no red color developed. -> no acetoin |
VP test what? | Acetoin. |
VP reagents? | VP A: Alpha Naphthol. VP B: Potassium hydroxide. |
Purpose of Citrate test? | Tosee if organism use citrate as its own carbon source. |
How to read result of Citrate Utilization? | Negative for Citrate Utilization: No growth, green color of medium. Positive: Growth on the slant, medium could be green color or blue color. |
Why use Indole? | used to identify if organism is capable of breaking down tryptophan to pyruvic acid, indole, ammonia by using enzyme tryptophanase. |
Why use Methol red? | used to see if bacteria produce acid from glucose |
Why use Voges Proskauer? | used to identify if org produce acetoin from 2,3-butanediol fermentation. |
Why use Citrate? | to see if org use citrate as it own carbon source. |
What products are formed from the Methyl Red test? | Mixture of acids |
What is the medium for Methyl red test? | MR-VP Broth |
What is the medium for Voges-Proskauer test? | MR-VP Broth |
What is the reagent of Methyl Red test? | MR red indicator |
What is the reagent for Voges-Proskauer test? | Barretts A and Barretts B |
What is the reagent for Catalase test? | Hydrogen Peroxide |
What is the reagent for Oxidase test? | Oxidase reagent |
What is the reagent for starch hydrolysis test? | Grams iodine |
What is the reagent for indole production test? | Kovac's reagent |
what product is formed from Voges-Proskauer test? | aceton |
what is the product from the Methyl Red test? | mixture of acids |
what is the product from the catalase test? | oxygen |
what is the product from the oxidase test? | none |