BIOL240L Lecture Notes - Lecture 18: Proteus Vulgaris, Bacillus Subtilis, Tryptone

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azureyellowjacket626

1 Dec 2017

School

University of Waterloo

Department

Biology

Course

BIOL240L

Professor

Cheryl Duxbury

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Document Summary

The carbohydrate fermentation test is used to determine if the bacterium can metabolize the specific carbohydrate, in this case, glucose, sucrose, and lactose, and produce acid and gas. After incubation, some tubes changed to yellow, indicating acid production, and some also had a bubble inside their durham tube, indicating gas formation. A positive reaction for this test is the production of both acid and gas formation, where the tube is yellow in solution, and the durham tube has a bubble inside it. This would show what carbohydrate fermentation is, where the bacterium can break down the carbohydrate it is placed in and produce acid and gas as a by-product. A negative reaction to this test would have no acid formation and no gas formed. Analysis of p. aeruginosa showed a negative reaction in all three carbohydrates. Bacterium, b. subtilis had acid formed (yellow solution) in glucose and sucrose, but no acid in lactose.

Related Questions

An organism can ferment lactose, and no gas is produced. What would you expect to see if you used this organism to inoculate glucose broth medium?

The broth will stay red and no bubble will be seen in the Durham tube.

The broth will stay red and a bubble will be seen in the Durham tube.

The broth will turn yellow and no bubble will be seen in the Durham tube.

The broth will turn yellow and a bubble will be seen in the Durham tube.

2. Please answer with a True or False for the following:

a. The catalase enzyme is found in all obligate aerobes and facultatuve anaerobes to deal eith H2O2

b. An exergonic reaction requires energy input and must be coupledwith ATP hydrolysis in order to proceed

c. The TCA cycle must "turn twice" in order to complete the oxidation of one glucose molecule.

d. Allosteric regulation occurs when an enzyme has a site that can bind an effector molecule seperate from the active site.

e. Some bacteria use desulfurases to produce hydrogen sulfide from he breakdown of some amino acids.

f. A 1/10 dilution can be made by adding 1 mL sample to 10mL diluent

3. You obtain the following results after incubation of a bacterial starin in tge indicated carbohydrate fermemtation sugar media:

Sugar: Color of Medium Durham tube results

Glucose Yellow No bubble

Maltose Red Bubble

Mannitol Yellow No bubble

Lactose Yellow Bubble

Sucrose Red No Bubble

Which sugars cannot be fermented by this bacterial strain?

a. glucose and mannitol

b. maltose and lactose

c. lactose

d. maltose and sucrose

e. none of the choices are correct

raspberrykoala332

Question 1

What is the last step of successfully preparing a bacterial smear for a simple stain?

		Spread cells with inoculating loop
		Label the slides
		Heat fixation
		Air dry the smear

Question 2

When looking at your smear under the microscope, all you see is darkness (despite shining light through your slide)- the best explanation is:

		all your bacteria are dead
		your smear was too thin
		forgot to add the bacteria
		your smear was too thick

Question 3

If a microbe can ferment lactose and its fermentation products include lactic acid and CO2, then the results for this assay should be:

		the broth will appear yellow and there will be a gas bubble in the Durham tube
		the broth will appear red and there will be no gas bubble in the Durham tube
		the broth will appear yellow and there will be no gas bubble in the Durham tube
		the broth will appear red and there will be a gas bubble in the Durham tube

True/Flase

Question 1

If the result for this carbohydrate test is negative, then the organism had NO growth in the tube.

Question 2

The biochemical basis of the Gram stain is the thickness of peptidoglycan layers surrounding cells. Therefore a Gram positive cell with a thin layer of peptidoglycan should stain as Gram negative.

Question 3

If the iodine is not applied during the Gram stain, then gram positive cells will likely stain pink

Question 4

A simple stain allows you to see the cell shape and arrangement.

Question 5

If there were no limit to magnification, a light microscope could enlarge microbes infinitely.

Question 6

When doing a bacteria smear from a broth medium you should first place one to two loopfuls of water on the center of the slide?

BIOL240L Lecture Notes - Lecture 18: Proteus Vulgaris, Bacillus Subtilis, Tryptone

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