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Lab Midterm
Dr. White--Lab
57
Microbiology
Undergraduate 3
02/22/2012

Additional Microbiology Flashcards

 


 

Cards

Term
Streptococci (Dividing)
Definition
Divide in a chain, one plane
Term
Tetracocci 
Definition

Dividing into 2 planes

 

Square Rectangle

Term
Staphylococci
Definition
divide in 3 planes irregularly
Term
Sarcinae
Definition
divide in 3 plains regularly
Term
Cationic Dyes
Definition
Basic dye, positive Charge chromophore
Term
Cationi Dyes Examples
Definition
Methylene Blue, Crystal Violet
Term
Anionic Dyes
Definition
acidic dyes, negatively charged chromophore
Term
Anionic Dye Example
Definition
Acid fuschin, Congo Red, Nigrosin 
Term
Fat Soluble Dye
Definition

no charge

 

Sudan Black stains granules of poly-B-OH-butyric acid

Term
Insoluble Dyes
Definition

water insoluble

 

India Ink

Term
Negative Stain
Definition

Stains background, not cell

 

Nigrosin: (-) charge repels membrane of cell

 

India Ink: insoluble dye, does not penetrate cell

Term
Simple Stain
Definition

Dyes same cell all the same color

 

Can tell morhpology and size of cell

 

Common Dyes: methylene blue, and crystal violet

Term
Differential Stain
Definition

Causes cell to stain differently based on properties of cell

 

 

Term
Gram Stain
Definition

Differential 

 

Based on characteristic of cell wall

 

Crystal Violet, Mordant:Iodine, Decolorizer:Ethanol, Counterstain:Saffranin

Term
Acid Fast Stain
Definition

Differential stain testing for high wax content of cells

 

Steam allows dye to penetrate cell

 

Primary Stain: Carbol Fuschn (red)

Steam

Decolorizer: Acid Alcohol (- test is colorless)

Counterstain: Methylene Blue (- test is blue)

Term

Acid Fast Organisms

 

(Acid Fast Positive)

Definition

Myrobacterium- if mature cell, because high wax content

if young cell, appear as gram+ tapered rod, sometimes fragment

 

Mycrobacterium: Tuberculosis and Leprae

 

Nocardia

Term

Spore Staining 

 

Structural Stain

Definition

Must be steamed to allow dye (malachite green)to enter spore

 

Endospores appear as green center with pink sporangium

 

Free spores as small green oval bodies

 

Primary: Malachite Green

Steam

Decolorizer: Water

Counterstain: Safranin

Term
Spore Forming organisms
Definition

Bacillus- Aerobic, gram + rod

 

Clostridium- Anaerobic, gram + rod

 

Sporsarcinae- Cocci

Term
Different Media Preperation
Definition

Pour= liquid agar--> pour plate

 

Broth= liquid media

 

Deep=media solidified in upright position

 

Slant= solidified at angled position

 

Fermentation Broth= broth with durham tube added

Term
Natural Media
Definition
Nutrient Agar
Term
Synthetic Media
Definition

Exact chemical composition known

 

Examples:

Selective Media- favors growth of one microorganism over another; inhibiting or providing nutrients

 

Differential Media- media distinguishing between different types of organisms based on apperance of growth or color changes

Term
Phenylethyl Alcohol Agar (PEA)
Definition

selects for growth of gram + microorganisms

 

PEA is inhibitory to the growth of gram (-) organisms

Term
Desoxycholate Agar (DES)
Definition

Selects for gram (-) microorganisms


Differentiates for lactose fermentors

 

Lactose fermentors produce acid, acid absorbs neutral red dye

Appearing Red

 

Non-fermentors do nor appear Red

Term
Eosin Methylene Blue (EMB)
Definition

Selects for gram (-) organisms

 

Differentiates lactose +/-

 

Lactose + shows color change

 

Lactose - no color change

 

 

Term

EMB 

 

Lactose + results, based on acid

Definition

Can further differentiate based on amounts of acid

 

Mixed Acid Fermentors produce more acid

colonies have dark blue-black centers

E.Coli- Metallic Green Sheen

 

Butanediol Fermentors produce less acid

colonies have pale pink to lavender centers

Term
Blood Agar
Definition

Differentiates organisms based on blood reaction

 

Gamma Hemolysis- None

 

Alpha Hemolysis- Partial hemolysis, partial clearing around colony; sometimes appear green

 

Beta Hemolysis- Complete blood hemolysis

Term
Biochemical Tests
Definition

Used to determine physiological characteristics of microorganism

 

Bacterial Enzymes and biooxidation

Term
Starch Agar
Definition

Tests for presence of Amylase--> hydrolyzes starch into simple sugar

 

Iodine added to plate and appears blue/black when interacting with starch

 

If amylase present, starch not present blue/black color not observed

Term
Milk Agar
Definition

Tests for presence of Caseinase

 

Hydrolyze Caseinase into amino acid product

 

Breakdown of caseinase causes agar to lose white coloring

Term
Sugar Fermentation Tubes
Definition

Determining if microorganism can ferment particular sugars

 

Test Tubes contain: sugar (glucose, lactose, mannitol)

pH indicator (phenol red)

Durham tube

 

Fermentation= acid increase changing color from red to yellow

 

Durham tube= testing if gas produced during fermentation

 

Alkaline Reaction= darkening of red pH indicator color

Yellow= acid

Yellow + gas= Acid, gas

Red to Dark red= Neg. or Alkaline

 

Term
Methy Red (MR)
Definition

HCOOH--> CO2 + H2

 

Tests for Mixed acid Fermentor

 

Mixed Acid Fermentor produce large amounts of acid

Acid drops below 5.1

When methyl red added, stays red

 

E. Coli = MR+

Term
Voges-Proskauer (VP)
Definition

HCOOH--> Acetyl methyl carbinol (AMC)--> 2,3 butanediol

 

Tests for 2,3 butanediol fermentor

 

2,3 butanediol fermentor produce less acid than mixed

 

AMC= acetoin is tested

 

VP1= Barrit's reagent, intensify possible red color

 

VP2= KOH, reacts with AMC to produce brick red color

 

Enterobacteria= VP+

Term
Catalase
Definition

2H2O2--> 2H2O and O2

 

Hydrogen peroxide toxic (produced in oxygen utilization), Catalase converts H2O2 into water and oxygen

 

Look for oxygen bubbles produced

Term
Oxidase
Definition

Oxidase can oxidize aromatic amines to form colored products

 

Amine used to test is dimethyl-p-phenylenediamine hydrochloride

 

If dimethyl-p-phenylenediamine hydrochloride+oxidase= turns blue/ black color

Term
Nitrate
Definition

NO3-+ 2e + 2H---> NO2 + H2O

 

NO2--> N2

 

Tests for ability to reduce nitrate

 

Reagents Nitrate I(Sulfanilic Acid

Nitrate II(dimethyl-alpha-naphthylamine)

 

NO2 present broth appears red--> Nitrate Positive

 

If not red, Zinc added to tube

Red after adding Zinc, Nitrate (-)

 

After Zinc added, if not Red

Nitrate (+)

Term
Tryptophan (Indole)
Definition

Tryptophan--> Pyruvic Acid and Indole

 

Tests for tryptophanase

 

Indole tested by adding Kovac's Reagent

 

Kovac's Reagent= p-dimethylaminobenzaldehyde, amyl or butyl alcohol, and HCl

 

Kovacs appears in presence of indole product

Term
Urea
Definition

Urea--> NH3 + CO2

 

Tests for Urease

 

Broth has urea and phenol red

 

As ammonia released pH rises, once above 8.1

Phenol Red appears Red 

 

Red coloring= Urease +

 

Proteus= Urease (+)

Term
Hydrogen Sulfide Production (H2S)
Definition

Cysteine--> H2S+ Amino Acrylic Acid--> Imino Acid--> Pyruvic Acid + NH3

 

Tests for cysteine defulfurase

 

Black precipitate= positive test for H2S 

 

Proteus= H2S positive

Term
SIM
Definition

Tests for Sulfur, Indole, Motility

 

H2S Positive= Black precipitate

 

Indole Positive= Kovacs Reagent turning Red

 

Motility positive= growth away from inoculant

Term
Simmons Citrate
Definition

Tests for Ability to utalize citrate as sole carbon source

 

Microorganism can grow on media and turn it a deep Prussian Blue 

 

Growth+ Blue Coloring= Positive Citrate organism

Term
Phenylalanine (PPA)
Definition

Phenylalanine--> Phenylpyruvic Acid (PPA) +NH3

 

Tests for presence of phynlalanase

 

To test for PPA, ferric chloride added to media

 

Ferric Chloride in PPA turns deep green

 

Deep green= positive

Term
Litmus Milk 
Definition

Test for Lactose fermentation, reduction of litmus, presence of caseinase, and the deamination of amino acids to produce NH3


pH indicator Litmus and powdered milk


Acid Reaction- Pink liquid due to drop in pH


Acid Curd- Pink solid acid production and coagulation of protein


Reduction- litmus reduced and turns white from milk


Alkaline Reaction- Blue liquid caused by protein breakdown


Proteolysis- Clearing of medium by caseinase

Term

Kliger's Iron Agar (KIA)

 

read 18 hours after inoculation (ideally)

Definition

Tests for fermentation of glucose/lactose, and production of H2S or gas

 

Fermentation= pH indicator

Glucose fermented= bottom yellow

Lactose fermented= all yellow

 

Black precipitate if H2S positive

 

Gas determined by slant movement

Term
OF Glucose
Definition

determining if bacteria can use glucose in aerobic or anerobic condition

 

2 test tubes innoculated

1 covered in mineral oil

contains pH idicator Brom Thymol Blue

 

§  Open Tube: Yellow, Closed Tube: Uninoculated color = Incompletely

        Oxidative (O)

§  Open Tube: Yellow, Closed Tube: Yellow = Strictly Fermentation (F)

§  Open Tube: Uninoculated color, Closed Tube: Uninoculated color = Strictly Oxidative

§  Open Tube: Uninoculated color, Closed Tube: Yellow = Facultative

Term
IMViC
Definition

Indol, Methyl Red, Voge-Proskauer, Citrate

 

E.Coli = + + - -

 

E. aerogenes= - - + +

Term
Motility Media
Definition

Test if bacteria are motile or not

 

Tetrazolium chloride, growth indicator

Term
Bismuth Sulfide Agar (BSA)
Definition
dull green color; Salmonella typhi produce black or very dark brown
Term
Brilliant Green Agar (BGA)
Definition

differential for lactose/ sucrose fermentation

 

lactose fermentig= yellow/green or yellow colonies

 

nonlactose= opaque red/pink/white colonies

Term
SS Agar
Definition

Salmonella ususally produces black colony

 

Shigella a colorless colony

 

all lactose + colonies appear red

Term
Desoxycholate Citrate
Definition

Selects for gram -, lactose - microorganism

 

some lactose + grow, but appear red

Term
Coagulase
Definition

incubate in plasma tube

 

if plasma becomes clumpy/ solidifies= bacteria coagulase +

 

test only valid on gram + staphylococcus

Term
Phenol Red Manitol Salt Agar (MSA)
Definition

selects for staphylococcus due to high salt conc.

 

medium is red (phenol red), but plate colonies yellow if mannitol +

Term
Staphylococcus 110 Medium
Definition

contains mannitol and 7.5% NaCl, lacks phenol red

 

natural colony pigment

Term
DNase
Definition

tests for exoenzyme DNase which hydrolyze DNA

 

Zones clear after addition of .1M HCl

 

Clearing= positive for DNase

Term
M-staphylococcus broth
Definition
10% NaCl selects staphylococcus, inhibits most others
Term
Endo Agar
Definition

selects for Gram -

 

Differential for lactose

 

lactose + = red colonies

 

Coliforms produce golden metallic golden sheen

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