Durham Tube Fermentation

used sugars dextrose(glucose), lactose, and sucrose. Acid rxn was yellow. Bubble meant positive for gas - CO2

bubbles indicate the bacteria produces catalase and break down hydrogen peroxide. Bubbles = O2

Only pseudomonas reacts to oxidase in our lab. Dark purple indicates a positive

iodine is a starch indicator. Brown/purple indicates starch is still present so it is negative. Clear means it is positive. Gram positive rods are positive in this test.

Mannitol Salt Agar (MSA)

selective and differential. only grows gram positive salt tolerant organisms (Micrococcus and Staphylococcus). An acid fermenter will produce acid that causes the pH indicator to turn yellow.

MacConkey and Eosin Methylene Blue (EMB)

selective and differential agars that grow only gram negative organisms (EMB is better at this than the MAC). Lactose fermenters have color (purple/pink) or E. coli produces a shiny green on EMB.

test to determine if your bacteria can use citrate as its sole carbon source. The tube starts out green and turns a pretty Prussian blue if positive.

that will indicate whether the bacteria use urea. A fuchsia pink color indicates an alkaline reaction which is positive.

Add Kovacs reagent to determine if the bacteria produce indole. A red ring on top is positive.

green to start and may have turned yellow to salmon pink (enteric that produced acid), may have produced blue/green colonies (no fermentation), or may have produced black precipitate (H2S production).

clear, turned red after added Nitrate reagent A & B (reduced nitrate to nitrite). Some come further & produce N2 gas, so must test to verify a (-) result.

Add zinc powder to a negative result. Red after zinc verifies negative (the zinc reacted to reduce nitrate). If it doesn’t turn red now, it means your test tube went the gaseous route and it was really positive for nitrate reduction.

Looking for black precipitate in these mainly. The black precipitate means it reduced sulfur and produced H2S.

Help

Options

focusNode

Didn't know it?
click below

Knew it?
click below

Don't Know

Remaining cards (0)

Know

retry

shuffle

restart

0:00

Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

Normal Size Small Size show me how

Micro Lab

Lab Final

Question	Answer
Durham Tube Fermentation	used sugars dextrose(glucose), lactose, and sucrose. Acid rxn was yellow. Bubble meant positive for gas - CO2
Catalase test	bubbles indicate the bacteria produces catalase and break down hydrogen peroxide. Bubbles = O2
Oxidase	Only pseudomonas reacts to oxidase in our lab. Dark purple indicates a positive
Starch Hydrolysis	iodine is a starch indicator. Brown/purple indicates starch is still present so it is negative. Clear means it is positive. Gram positive rods are positive in this test.
Mannitol Salt Agar (MSA)	selective and differential. only grows gram positive salt tolerant organisms (Micrococcus and Staphylococcus). An acid fermenter will produce acid that causes the pH indicator to turn yellow.
MacConkey and Eosin Methylene Blue (EMB)	selective and differential agars that grow only gram negative organisms (EMB is better at this than the MAC). Lactose fermenters have color (purple/pink) or E. coli produces a shiny green on EMB.
Simmons Citrate	test to determine if your bacteria can use citrate as its sole carbon source. The tube starts out green and turns a pretty Prussian blue if positive.
Urease broth	that will indicate whether the bacteria use urea. A fuchsia pink color indicates an alkaline reaction which is positive.
Indole	Add Kovacs reagent to determine if the bacteria produce indole. A red ring on top is positive.
Hektoen Enteric agar	green to start and may have turned yellow to salmon pink (enteric that produced acid), may have produced blue/green colonies (no fermentation), or may have produced black precipitate (H2S production).
nitrate broth	clear, turned red after added Nitrate reagent A & B (reduced nitrate to nitrite). Some come further & produce N2 gas, so must test to verify a (-) result.
nitrate negative	Add zinc powder to a negative result. Red after zinc verifies negative (the zinc reacted to reduce nitrate). If it doesn’t turn red now, it means your test tube went the gaseous route and it was really positive for nitrate reduction.
SIM and/or Kliglers	Looking for black precipitate in these mainly. The black precipitate means it reduced sulfur and produced H2S.

Created by: tifferbaby86

Popular Biology sets

Genetics: Monohybrid, Dihybrid, & Non-Mendelian

Unit 2- Requirements of Life

Evidence of Evolution

"Know" box contains:
Time elapsed:
Retries: