Microbio Lab Practical #2

Amoeba

Supergroup: Unikonta

Subgroup: Gymnamoeba

Saccharomyces cerevisiae

Supergroup: Unikonta

Subgroup: Fungus

Characteristics: budding yeast cells

Euglena

Supergroup: Excavata

Subgroup: Euglenozoa

unicellular, green, autotrophs

Euglena

Flagellum

Stigma: (eyespot) red

Chloroplast

Vacuole

Chlamydomonas

Supergroup: Archaeplastida

Subgroup: Chlorophyte

Chlamydomonas

F: Flagella

C: Chloroplast

S: stigma (red)

Volvox

Supergroup: Archaeplastida

Subgroup: chlorophyte

Spirogyra (vegetative)

Supergroup: Archaeplastida

Subgroup: Charophyte

filamentous alga that contains spiral chloroplasts and contains nucleus

Spirogyra (vegetative)

N: Nucleus

C: Chloroplast (spiral)

Spirogyra (conjugative)

Supergroup: Archaeplastida

Subgroup: Charophyte

two filaments beginning conjugation, they share cytoplasm and genetic material, contains zygospore

Spirogyra (conjugative)

Zygospore

Paramecium

Supergroup: SAR

Subgroup: Alveolate

Paramecium

C: Cilia

Mi: Micronucleus

Ma: Macronucleus

Stentor

Supergroup: SAR

Subgroup: Alveolate

naturally green, trumpet shape, cilia, M: macronucleus

Diatom

Supergroup: SAR

Subgroup: Stramenopile

lack flagellum, can be pennate (bilateral symmetry), has a cell wall

Diatom

centric shape (radical symmetry)

Bacillus cereus (simple stain)

Stain: Crystal Violet

Shape: Rod

Purpose of Stain: Cell morphology, size and arrangement can be determined

Arrangement: Streptobacilli

Why it stains: Stains have a positive charge that gets attracted to the negative charges on the bacteria making it stained.

Micrococcus luteus (simple stain)

Stain: Methylene blue

Shape: coccus shape

Purpose of stain: Cell morphology, size and arrangement can be determined

Arrangement: Staphylococcus (irregular clusters)

Why it stains: Stains have a positive charge that gets attracted to the negative charges on the bacteria making it stained.

Rhodospirillum rubrum (simple stain)

Stain: Safranin

Shape: spiral

Purpose of stain: Cell morphology, size and arrangement can be determined

Arrangement: Spiral

Why it stains: Stains have a positive charge that gets attracted to the negative charges on the bacteria making it stained.

Bacillus cereus (negative stain)

Stain: nigrosin

Shape: rod

Purpose of stain: Cell morphology, size, and arrangement can be determined

Arrangement: Streptobacilli

Why it does not stain: The stain contains chromogen which is negative, and the bacteria are negative so it repels the stain making the background stained.

Micrococcus luteus (negative stain)

Stain: nigrosin

Shape: coccus

Purpose of stain: Cell morphology, size, and arrangement can be determined

Arrangement: Staphylcoccus (irregular clusters)

Why does it not stain: The stain contains chromogen which is negative, and the bacteria are negative so it repels the stain making the background stained.

Rhodospirillum rubrum (negative stain)

Stain: nigrosin

Shape: spiral

Purpose of stain: Cell morphology, size, and arrangement can be determined

Arrangement: spiral

Why does it not stain: The stain contains chromogen which is negative, and the bacteria are negative so it repels the stain making the background stained.

Bacillus cereus (gram stain)

Stains: Crystal violet and Safranin

Shape: rod

Purpose of stain: Cell morphology, size, and arrangement can be determined

Color: Purple

Reaction: Positive

Reagents used and purpose: It is called a differential stain because decolorization occurs between two stains. Crystal violet is the primary stain. Iodine is added (enhances crystal violet staining), then decolorization happens to gram negative cells with alcohol while gram positive stays purple. Safranin is added making gram negative cells red.

Escherichia coli (gram stain)

Stains: Crystal Violet and Safranin

Shape: bacillus

Purpose of stain: Cell morphology, size, and arrangement can be determined

Color: Reddish/pink

Reaction: Negative

Reagents used and purpose: It is called a differential stain because decolorization occurs between two stains. Crystal violet is the primary stain. Iodine is added (enhances crystal violet staining), then decolorization happens to gram negative cells with alcohol while gram positive stays purple. Safranin is added making gram negative cells red.

Micrococcus luteus (gram stain)

Stains: Crystal violet and safranin

Shape: coccus

Purpose of stain: Cell morphology, size, and arrangement can be determined

Color: Purple

Reaction: Positive

Reagents used and purpose: It is called a differential stain because decolorization occurs between two stains. Crystal violet is the primary stain. Iodine is added (enhances crystal violet staining), then decolorization happens to gram negative cells with alcohol while gram positive stays purple. Safranin is added making gram negative cells red.

Rhodospirillum rubrum

Stains: Crystal violet and safranin

Shape: spiral

Purpose of stain: Cell morphology, size, and arrangement can be determined

Color: Reddish/pink

Reaction: Negative

Reagents used and purpose: It is called a differential stain because decolorization occurs between two stains. Crystal violet is the primary stain. Iodine is added (enhances crystal violet staining), then decolorization happens to gram negative cells with alcohol while gram positive stays purple. Safranin is added making gram negative cells red.

Mycobacterium smegmatics (acid fast stain)

Purpose of stain: To detect cells capable of retaining a primary stain when treated with alcohol.

Reagents used and purpose: Acid fast organisms contain mycolic acids (waxy substance) in cell wall which gives it a higher affinity for the primary stain and resistance to decolorization by acid alcohol. Carbolfuchsin is used as the primary stain because its lipid soluble and penetrates the cell wall making it red. After alcohol is applied methylene blue is the counterstain.

Why do we steam: helps melt the wax and allow the stain to move in

Reaction: Positive

Color: Reddish purple

Shape: bacillus

Staphylococcus epidermis (acid fast stain)

Purpose of stain: To detect cells capable of retaining a primary stain when treated with alcohol.

Reagents used and purpose: Acid fast organisms contain mycolic acids (waxy substance) in cell wall which gives it a higher affinity for the primary stain and resistance to decolorization by acid alcohol. Carbolfuchsin is used as the primary stain because its lipid soluble and penetrates the cell wall making it red. After alcohol is applied methylene blue is the counterstain.

Why do we steam: helps melt the wax and allow the stain to move in

Reaction: Negative

Color: Blue

Shape: coccus

Bacillus cereus (endospore stain)

Purpose of stain: detect presence, shape, and location of endospores in cells

Reagents used and purpose: Malachite green is used as primary as it is water soluble and it is to go against the keratin on the spore. This allows the spore mother cell to be counterstained with safranin.

Why we use steam: It forces the malachite green into the spore

Color: Red with green endospore

Endospores: yes

Free spores: no

Bacillus cereus (endospore stain)

Purpose of stain: detect presence, shape, and location of endospores in cells

Reagents used and purpose: Malachite green is used as primary as it is water soluble and it is to go against the keratin on the spore. This allows the spore mother cell to be counterstained with safranin.

Why we use steam: It forces the malachite green into the spore

Color: Red

Endospores: no

Free spores: yes