How does amylase hydrolyze starch?

It breaks the bonds between the glucose chains.

What is an exoenzyme?

It is an extracellular enzyme that bacteria secret in order to break down and hydrolyze macromolecules.

What is a starch?

A large polymer made up of units of glucose.

What is starch used for?

Energy storage in plants and many microbes.

What is the exoenzyme of starch?

Amylase

How does amylase work?

It diffuses away from the microbe and clears the starch outside of the cell.

What is the indicator used in starch hydrolysis?

Gram's Iodine

What is a positive result for starch hydrolysis?

There will be a clear zone because the starch has been ingested and is no longer there. The iodine can not stick to what is not on the plate.

What is a negative result for starch hydrolysis?

There will be a blue/black complex because Gram's iodine will stick to the stain and dye it.

What type of plate is the bacteria added to for observing starch hydrolysis?

Starch agar

What are the end products of starch hydrolysis?

Dextrin and maltose

Starch is a special type of carbohydrate called

a polysaccharide

What is the purpose of a control?

To see if any changes are appearing on the testing for hydrolysis. The control should always be a negative result to compare against other negative results.

The detection of enzymatic activity on starch

is based upon the disappearance of the starch

The specific amylase, glucoamylase results in the end product

glucose

What is a lipid?

a large polymer made of fatty acids and glycerol; sometimes complexes with phosphate, nitrogen and sulfur

What type of media is used for lipid hydrolysis?

Spirit Blue Agar

An important property of lipids in the presence of water

They are hydrophobic.

What is the exoenzyme secreted by bacteria in lipid hydrolysis?

Lipase

What is a positive result for lipid hydrolysis?

There will be a more intense blue color that forms around or under bacterial growth due to the release of fatty acids and the uptake of spirit blue.

What is a negative result for lipid hydrolysis?

There is no color change on the media is present.

Another term for lipid hydrolysis

lipolysis

What is the dye in the agar that serves as the indicator of lipolytic activity?

Spirit Blue

A lipase produced by C. perfringens causes ______ of RBCs by removing ________________ from certain membrane lipids.

lysis and phospholipids

What is a protein?

large polymer made up of repeating units of amino acids

What is the class of enzyme that hydrolyzes proteins into small fragments?

Proteases

What is important about proteases?

They are specific to a particular substrate or for a specific amino acid sequence.

Process of protein hydrolysis is called

Proteolysis or peptonization

What type of agar is used in gelatin protein hydrolysis?

Gelatin agar

What is the protease that hydrolyzes gelatin protein?

Gelatinase

What is the method used in gelatin protein hydrolysis?

Fraser overlay method

What is a positive result of gelatin protein hydrolysis?

No white precipitate forms upon being acidified because the protein has been digested by the bacteria and is no longer present.

What type of indicator is used in determining gelatin protein hydrolysis?

Acid

What is a negative result of gelatin protein hydrolysis?

White precipitate forms upon being acidified because acid denatures proteins and causes the white precipitate to form meaning that the protein is on the plate and has not been ingested by the bacteria.

At room temperature, gelatin is

solid

Gelatin is derived from the animal substance

collagen

Using the plate overlay method, what indicator is added?

acidified mercuric chloride

The tube method of gelatin hydrolysis is less sensitive than

the Fraser overlay method.

Collagen degradation is detected by the release of a

Collagenase

Gelatinase activity results in the disappearance

of the gelatin

What is the protease that hydrolyzes the milk protein, casein?

caseinase

What type of media is used in casein protein hydrolysis?

Skim milk agar

What is a positive result for casein protein hydrolysis?

Milk agar plate appear clear around the colony because the casein is ingest so there is no more cloudy milk appearance.

What is a negative result for casein protein hydrolysis?

Milk agar plate appears cloudy around the colony.

Casein is a protein

found in milk

Term used to describe casein hydrolysis specifically

peptonization

The colloidal nature of milk serves as

the basis for interpreting casein hydrolysis

A special chemical reagent

is not added to test for casein protein hydrolysis

What is a nucleic acid?

Large polymers of nucleotides that can be RNA or DNA

The enzyme produced by bacteria that can break down nucleic acids to use the energy stored in those polymers in order to metabolize

exonucleases

What type of media is used in determining nuclease activity?

Agar plate with DNAse

What are the two methods used for detecting nuclease activity?

Inoculated test plate developed with HCL and Toluidine Blue Agar plate

What is a positive result for DNA hydrolysis on the inoculated plate with HCL?

Clear zone because nucleic acid is hydrolyzed.

What is a positive result of DNA hydrolysis on a Toluidine Blue Agar Plate?

Pink/red zone and clear area surrounds the colony of bacteria

What is a negative result of DNA hydrolysis on a Toluidine Blue Agar Plate?

No color change or change in appearance of the blue agar plate.

What is the bacteria that causes food poisoning?

S. aureus

What is the media used in blood hemolysis?

5% sheep blood agar

What are the exoenzymes that destruct red blood cells and hemoglobin?

Hemolysins

What are the three terms used to describe hemolysis?

Alpha, beta and gamma hemolysis

What is Alpha Hemolysis?

partial destruction of RBCs and hemoglobin; cloudy/green zone around the colony

What is Beta Hemolysis?

complete destruction of RBCs around bacteria and hemoglobin is discolored. Clear zone around colony

What is Gamma Hemolysis?

Non-hemolysis; no change in the media because no RBC/hemoglobin destruction

Hemolysis is best observed

against a light background

What are the end products of protein hydrolysis

peptones and amino acids

What are the end products of lipid hydrolysis?

fatty acids and glycerol

Alpha-amylase cleaves starch to

oligosaccharides, maltose and glucose

Beta-amylase cleaves starch to

dextrins and maltose

Glucoamylase cleaves starch to

glucose

What is another term for lipases?

triacylglycerol acyhdrolases

Once inside the cell, fatty acids can be used for

energy or building blocks for biosynthesis

Bacteria forming exonucleases can

utilize the carbon, nitrogen and end products of large polymers of RNA or DNA

What is thermostable mean?

a nuclease, bacteria can secrete that withstands boiling temperatures

Why is the thermostable property useful in identitying S. aureus food poisoning organisms?

When heating has destroyed the organisms but the nuclease is still present.

Pathogenic strains of streptococci are

non hemolytic