Quiz On Acid Fast Spore Stains And Decarboxylase

Question 1

What is the cytological basis for the acid fast differential stain?

Answer 1

Mycolic acids in the cell wall of acid fast organisms

Question 2

What is mycolic acid?

Answer 2

A waxy substance that gives acid fast cells a higher affinity for the primary stain and resistance to decolorization by an acid alcohol

Question 3

Two examples of acid fast staining procedures

Answer 3

Ziehl- neelsen ( zN)
And
Kinyoun (k)

Question 4

Difference between the ZN method and the K method of acid fast stain

Answer 4

Zn uses heat as part of the staining process whereas K is a cold stain

Question 5

What is the primary stain of an acid fast stain?

Answer 5

Carbolfuchsin

Question 6

What does the waxy wall of acid fast cells do to aqueous stains?

Answer 6

Typically it repels them making them only weakly gram-positive

Question 7

What type of cell is an acid fast stain trying to detect

Answer 7

Cells capable of retaining a primary stain when treated with an acid alcohol

Question 8

What is used as the decolorization in an acid fast stain?

Answer 8

Acid alcohol

Question 9

What is the counter stain used in an acid fast stain?

Answer 9

Methylene blue or brilliant green

Question 10

What color are acid fast and acid fast negative cells prior to staining in an acid-fast stain

Answer 10

Both are transparent

Question 11

After staining with carbolfuchsion in an acid fast stain

Answer 11

Both acid fast and acid fast negative are reddish purple

Question 12

What color is acid fast and acid fast negative after decolorization in an acid fast stain

Answer 12

Acid fast is reddish purple
Acid fast. Negative is transparent

Question 13

What color is acid fast and acid fast negative after the counter stain in an acid fast stain

Answer 13

Acid fast is reddish purple
Acid fast negative is blue or green

Question 14

What is an endospore?

Answer 14

A dormant cell that forms in environmental conditions such as nutrient depletion or high temperatures that are unsuitable for growth

Question 15

Are endospores resistant to heat and chemicals?

Answer 15

Yes, so they can live in this state for long periods of time

Question 16

Is there ATP within an endoscore

Answer 16

No

Question 17

What two factors are sporulation dependent on?

Answer 17

Nutrient depletion and population density

Question 18

How does population density affect endospore generation and how does it work

Answer 18

With increased density a secreted peptide called a competence and sporylation factor ( CSF) reaches a critical concentration and results in sporrelation genes starting

Question 19

What is an endosports tough outer covering made of?

Answer 19

keratin

Question 20

When conditions are suitable again for growth, what happens to endospores?

Answer 20

They germinate into metabolically active vegetative cells

Question 21

What happens when you try and stain an endospore?

Answer 21

It’s Spore coat resist staining because of the keratin

Question 22

What is a spore mother cell?

Answer 22

A cell responsible for producing the endospore

Question 23

What are the three locations of an endospore in a cell?

Answer 23

Middle of the cell called Central
End of the cell called terminal
Between the end and middle of the cell called subterminal

Question 24

Is a. Spore always in the same location

Answer 24

No in some species. The location is variable

Question 25

How can endospores be differentiated?

Answer 25

With their shape either spherical or elliptical( oval) And the spores shape relative to the size of the cell

Question 26

Color of Spore producing cells and non-spore producing cells prior to staining

Answer 26

Spore producing cells are transparent Non-spore producing cells are also transparent

Question 27

After staining with the primary stain of malachite green and with heat, what color are the cells?

Answer 27

Spore producing cells are green all the way through Non-spore producing cells are green all the way through

Question 28

After decolorization with water, what color are cells in an endospore stain?

Answer 28

Spore producing cells are transparent with a green Center Non-spore producing cells are transparent

Question 29

After safrinin is used as a counter stain in an endospore stain, what color are the cells?

Answer 29

Spore producing cells are red with a green Center Non-sport producing cells are red all the way through

Question 30

What is the primary stain in an endospore stain

Answer 30

malachite green

Question 31

What is the decolorizer in an endosport stain

Answer 31

Water

Question 32

What is the counter stain in an endospore stain?

Answer 32

Safranin

Question 33

A type of bacteria that typically makes spores

Answer 33

Bacillus

Question 34

What four things do mollers decarboxylase medium contain?

Answer 34

Peptone Glucose The pH. Indicator bromocresol purple And the coenzyme pyridoxal phosphate

Question 35

At what pH is bromocresol purple actually purple And when is it yellow?

Answer 35

6.8 or above it's purple It's yellow at pH 5.2 or below

Question 36

After inoculation what is used to seal the medium from external oxygen and promote fermentation

Answer 36

An overlay of mineral oil

Question 37

What does glucose fermentation do to the color?

Answer 37

In the anaerobic medium initially it turns yellow because of the accumulation of acid end products

Question 38

The low pH and presence of the specific amino acid induces what

Answer 38

Decarboxylase positive organisms to produce the enzyme meaning that the gene is switched on

Question 39

Decarboxylation of the amino acids results in what?

Answer 39

The accumulation of amines which are alkaline and then turn the medium purple

Question 40

If the organism is a glucose fermenter but does not produce the appropriate decarboxylase, what color does it turn?

Answer 40

Yellow and remains so

Question 41

If the organism does not ferment glucose, what color does it turn?

Answer 41

The medium will exhibit no color change

Question 42

What is the only positive result in color for decarboxylation

Answer 42

Purple all other colors are negative

Question 43

What are the three amino acids tested most frequently for decarboxylase activity

Answer 43

Arginine Lysine Ornithine

Question 44

What is the dihydrolase system?

Answer 44

A second pathway for arginine catabolism In this system. Arginine is converted to citrulline and then into ornithine ATP CO2 and two NH3 raises the pH and then turns the medium purple If the species is also positive for orthanine decarboxylase it will produce putrescine and CO2 from ornithine

Question 45

Decarboxylase media can include one of several amino acids. Typically these media are used to differentiate what

Answer 45

Organisms in the family enterobacteriacae and to distinguish them from other gram-negative rods