Microbiology Lab - Practical 2

Acetylmethylcarbinol (AMC)

A positive test is produced when the substrate has been utilized and broken down into a neutral end product. What is the name of end product?

hemolysis

According to the growth on plate A and the results in the surrounding media, what has taken place?

halotolerant

Bacteria that can grow on this type of selective media are generally said to be .

Methyl Red media

For the Vogues Proskauer, which media is split so that half is used as the VP test and the other half is used for the other test?

Iodine

For this Starch plate, what reagent would need to be added in order to evaluate starch hydrolysis?

Sodium thiosulfate

H2S is the byproduct of the breakdown of what ingredient in the TSI?

superficial streak on the slanted surface

How would this Simmons Citrate agar be inoculated correctly?

pH indicator

If the end products change the pH of the media, what ingredient (usually already added to the media) would allow us to determine that the pH has been changed?

non-lactose fermenter or gram-negative

If you had a MacConkey plate that after incubation, had growth but no coloration, you could safely say that your bacteria is a

All of the above

If you inoculated a sample onto an EMB plate and had the results of Plate A, what could you immediately conclude about that sample?

ph is alkaline

In Tube A, the substrate has been broken down into its end products. What can we now conclude about the pH of the media?

Indole

In Tube A, what does the pink layer on top of the SIM media indicate?

Phenylalanine deaminase

In Tube B, what enzyme can we conclude that the organism produced?

ferment the mannitol.

In order for the reaction above to occur (yellowing of media), what do the bacteria have to do?

multiple

In the Methyl Red media, how many acid end-products is the test detecting?

glucose

In the test above, what is the name of the substrate that must be utilized for the outcome of the test to be positive?

indole

In this media, there are 3 results to look for. By adding the reagent above, which result are you scoring?

lactose fermenter, gram negative, or gram-negative rod

Looking at the growth on this MacConkey plate, we can conclude that this bacteria is a

MacConkey agar (MacConkey agar inhibits gram positive bacteria, allowing gram negative bacteria to flourish.)

Looking at this Gram stain, the bacterial cells would be most likely to grow on MacConkey agar or Mannitol Salt Agar?

proteus (Researchers believe that 60% of kidney and bladder stones are primarily composed of Proteus mirabilis.)

Name a common organism that would give a positive Urea Test.

bacterial capsule

Name the structure that gives a halo appearance in this particular stain.

A (Tube A shows the reddish-pink aqueous layer indicative of Indole production.)

Of the 2 SIM tubes shown here, which one is positive for Indole production?

B and C (Both of these tubes had bacteria that produced acid wastes upon fermentation of glucose, which triggered the phenol red pH indicator to turn the media yellow.)

Of the 3 TSI tubes, which ones show an Acidic Butt?

candida or candida albians budding

One yeast that can potentially cause several diseases is called One process by which yeast divide is though uneven cell division called

YES (Heat-fixing must be done to most all bacterial smears (with the exception of Capsule stains))

Question 2:Would the bacterial smear used for this gram stain be heat-fixed?

Methyl Red reagent

Specifically for the Methyl Red test, what reagent do we add (after incubation) to determine if the pH of the media has been changed?

hydrogen sulfide.

The black coloration indicates the production of what substance?

spores or conidia penicillium fruiting body

The chains of ball-shaped structures in the image are referred to as This organism is most likely what Genus ? The entire brush-like structure, containing the chains of ball structures is called the .

motility or movement

The majority of the bacteria in this field of view have outer projections called flagella. What would these flagella be useful for?

Kovac's reagent

The name of the aqueous layer on the top of the SIM media is

survival

The structure stained here is not a reproductive structure. What primary function does this structure have?

pyruvate

The substrate is broken down into 3 end products: ammonia, indole, and

false

These structures can easily be rendered unviable by detergents, chemicals, and heat.

zygospore

This image shows what type of fungal structure?

Cytochrome c oxidase Square B

This is an Oxidase Dry Slide. What enzyme does a positive test reveal that the organism produces? Which square is positive for the production of the proposed enzyme?

7.5% sodium chloride

This particular type of media, Mannitol Salt Agar, contains a selective ingredient that makes it inhospitable for most microbial growth. What is that ingredient (be specific)?

Eosin and methylene blue

What are the selective ingredients for this media?

spores or endospores

What are the stained structures represented in the micrograph here?

Production of an alkaline end product

What changes the pH in Tube A?

neutral red

What is the ingredient in this media that causes the change of coloration due to production of acid wastes and lowering of pH?

catalase bubbles hydrogen peroxide

What is the name of the enzyme for which this reaction is testing? What does a positive result look like? (enter what is produced) What reagent is applied to bacteria to determine a positive or negative result?

Amylase

What is the name of the enzyme that bacteria may produce in order to break down Starch?

Spirit Blue agar lipase

What is the name of this agar? For what exoenzyme is this media testing for?

sporangium Rhizopus

What is the name of this structure? What genus of organism would likely produce the structure in the image?

collects gas

What is the purpose of the Durham tube inside this Carbohydrate Fermentation test?

Kovac's reagent

What reagent is added to the SIM media to visualize the above reaction?

none

What type of sugar does the Urea Test utilize as a substrate?

red

What would a positive result look like when adding this reagent?

The bacteria would die and no color change would occur.

What would happen if, when storing the inoculated media in the incubator, the tube's cap was placed on too tightly?

sodium citrate

When using this agar, what is the sole carbon source available for the bacteria?

Tube A collagen amino acids the media is stabbed

Which gelatin hydrolysis tube illustrates a positive result? Gelatin is a protein derived from The gelatin is hydrolyzed into How is this media inoculated?

You forgot to place oil on top of the media before incubating. Tube A ferments glucose Purple coloration of media

You inoculated your bacterium into an ornithine decarboxylase tube and came back to the lab after 48 hours. You see absolutely NO change in the media from when you first inoculated it. What could possibly have gone wrong? In regards to the Tubes shown in the image: Which one fermented glucose? How can one tell that a decarboxylation reaction has occurred?

Starch

in the Starch media, the substrate is starch which is broken down into ___________ subunits as end products.

tryptophan.

what is the substrate that the bacteria must utilize for the positive reaction shown in the image?