Prescott's Microbiology: Micro 225 Lab Exam #3 final Flashcards

Biochemical test: Lipase
Medium used: Marian fat agar plate, tributyrin is added to agar
Red color of fat agar due to neutral red pH indicator

Positive: colony turns red (may also turn red-pink around & below colony)
-Lipase produced
-free Fatty acids are liberated from hydrolysis of triglyceride
-Neutral red precipitates turn red from acidic pH of fatty acids
Aeromonas hydrophila = +

Negative: no evidence of red color on or around colony
-No lipase production
-Neutral red remains as amber color from neutral pH (no color change)
Photobacterium phosphoreum= -

Biochemical test: presence of Amylase
Medium used: Marine starch agar plate
Flood area of spot inoculation with Gram's Iodine: Chemically reacts with starch =blue-black color

Positive: clearing around colony (halo)
-Amylase produced
-Some starch digested
-NO binding of iodine around colony due to starch breakdown
Aeromonas hydrophila = +

Negative= NO clearing around colony (no halo)
-NO amylase production
-No starch digested
-Iodine binds to starch on all parts of the plate
Photobacterium phosphoreum= -

Biochemical test: Gelatinase produced
Gelatinase is an enzyme that liquefies gelatin
Medium used:Marin nutrient gelatin agar plate

Positive: liquefaction of gelatin
-Part or all does not re-solidify
-Gelatinase produced
-Gelatin digested
Aeromonas hydrophila = +

Negative: Gelatin remains solid
-Re-solidifies with refrigerated
-NO gelatinase produced
-NO Gelatin digested

Photobacterium phosphoreum= -
If NEGATIVE, continue incubation at unknown's preference temperature:
-Repeat refrigeration test each lab for up to 2 weeks
-Do not leave gelatin tubes in refrigerator

Metabolism of lysine/ornithine by decarboxylation or arginine by dihydroxylation, then decarboxylation
-Lysine (LDC)
-Ornithine (ODC)
-Arginine (ADH)

Removes acid groups- carboxyl groups (COOH) from amino acids & other organic molecules. Only activated by acidic environments: fermentation
-Neutralizes acids: survival mechanism; Amines released increases pH

Metabolism of lysine/ornithine by decarboxylation or arginine by dihydroxylation, then decarboxylation

Positive Results:
DC=Yellow
-Glucose fermentation
-Acid produced
-Brom-cresol purple (pH indicator) turns yellow

LDC, ODC, ADH= Purple
-Acids from glucose fermentation stimulated decarboxylase
-Amine neutralizes acids
-pH indicator turns purple

Negative results:
DC=Yellow
-Glucose fermentation
-Acid produced

LDC, ODC, ADH=Yellow
-Acids produced from glucose fermentation
-No Decarboxylase release
-No acid neutralization

Negative results:
DC=purple
-Glucose not fermented
-Acids not produced

LDC, ODC, ADH= Purple
Decarboxylase no produced

Medium used: Methyl red voges proskauer broth (MRVP) + Marine cations 1559.
Preform test by adding KOH & Alpha mix ever few mins for entire lab
-measure the ability of an organism to produce non-acid products (neutral pH) from glucose

Results:
Voges Proskauer Positive= Butanediol Fermenter
If Reddish pink color slowly develops: Positive
P. phosphoreum= +

NO color change: Negative= Non-fermenter or fermentation pattern
Vibrio fischeri= -

-May take min-hours to develop leave with instructor in rack up front if still negative at the end of lab

Medium used: Peptone broth for idone +Marine cation 1559, contains tryptophan and can detect motility of organism
Perform test by Add Kovac's reagent to top

Positive= pink-red color on top
presence of Indole
-tryptophanase produced from tryptophan utilization
-Idole detected

Negative: No color change
Photobacterium phosphoreum= -

Medium used: Marine Glucose Fermentation broth, view wet mount under phase contrast microscopy

-energy reserve-> Carbon and energy source
-Produced under high Carbon conditions for later

P. phosphoreum=-
V. logei & V. fischeri= +

Mycology

Molds, yeasts, mushroom, relatives

-Eukaryotes
-Nonphotosynthetic-heterotrophs
-Absorptive metabolism- Exoenzymes

-Lack tissue differentiation
-Cell wall of chitin/ other polysaccharides

Propagate by spores (sexual/Asexual)
-Deuteromycota division (defunct, term of convenience for non-sexually reproducing fungi) -most now in Ascomycota

Primary terrestrial, a few freshwater and marine

-Symbionts of plants or animals- commensals, mutualistic, parasitic
-Mutualist:
*Form associations with plant roots (mycorrhizae) - Assist with N & P uptake
* Association with Algae or cyanobacteria (lichens)

Mutualist:
*Form associations with plant roots (mycorrhizae) - Assist with N & P uptake
-Redwood seedling without (left) & with (right) mycorrhizae
-Pine seedling- mycorrhizal roots from one tree spread to inoculate other tree roots

Decomposers (saprophytes)- break down organic material & return to environment
-Pathogens: mycose of animals & plants

Industrial fermentation- bread, wine, beer, cheese, tofu, soy sauce, steroid manufacture, antibiotic production

multicellular filamentous fungi

1. Zygomycota
2. Ascomycota
-Deuteromycota division (defunct, term of convenience for non-sexually reproducing fungi) -most now in Ascomycota
3. Basidiomycota
4. Chytridiomycota

-Thallus: fungal body or vegetative structure
-Chitin: N-containing polysaccharide (cell wall of some fungi)

Ascomycota- also contains some molds

1. Plasma membrane
2. Chitin microfibrils
3. Cytoplasmic microtubule
4. Cluster of ribosomes
5. Smooth endoplasmic reticulum
6. Mitochondria
7. Rough ER
8. Cell wall
9. Meshwork of microfilaments
10. Plasma membrane invagainations

Vegetative (reproductive) hyphae- structures that elongate into branching multicellular filaments
-Hyphae may be septate (contain dividing cross walls) or coenocytic (cross walls absent)

1. Cell wall
2. Pore
3. Nuclei
4. Septum
a) Septum hyphae
b) Coenocytic hyphae

Hyphae intertwine to form a aerial mycelium on substrate surface- puffy colonies
-Vegetative mycelium seen on underside of plates

1. Spore: non-motile reproductive units on end of hyphae- useful for ID (development & morphology)
c) Growth of a hypha from a spore

Conidiophores bear long chains of asexual conidiophores.
-conidiophores break away & can germinate to form new vegetative hyphae
1. Conidiophores
2. Conidiophore

Sporangiophores bear sac (sporangium) that contains sporangiospores.
1. Sporangiospores
2. Sporangium
3. Sporangiophores

Vegetative mother cells bear single blastospores that bud off.
1. Blastospores
2. Vegetative mother cell

Arthrospores-hyphae fragment apart & the component function as spores.
a. Arthroconidia (arthrospores)
b. Fragment hypha

Transverse tissue forming new cell wall

a. Terminal chlamydospores
b. Chlamydospore within a hypha

Yeast structure; spherical, ellipsoidal, or oval
-Most much larger than bacteria: 3-4 um
-Except for dimorphic yeast (Candida form pseudohyphae) hyphae are not formed

Yeast colonies- appear like bacteria, often dull and opaque

Yeast Cell:
1.Nucleus
2. Cytoplasm
3. Polar bud scar
4. Mitochondrion
5. Plasma membrane
6. Golgi apparatus
7. Nuclear envelope
8. Plasma membrane
9. Chromosome
10. Polar bud Scar
11. Cell wall

Dimorphism

a. Spores
b. Hyphae
c. spores
d. Bud
e. Yeast

1. Increased Temperature, Reduced O2, Suboptimal nutrients
1a. When fungal spores from the environment gain entrance to a warm-blooded animal , they germinate into yeast and remain in this phase in the host.
Animal Habitat: Parasitic, Yeast phase
Temp: 35-45 C)
Reproduction through: endospores

2.Decreased temperature, Optimal O2 content, Improved nutrients
2a. Yeast cells leaving the animal host return to the environment and revert to the sporulating hyphal stat. These conversions can be demonstrated on artificial media in the lab.
Natural Habitat:Saprobic (free-living), Mycelial phase
Tem: (<30 C)
Reproduction through: sporulation

alternate between a saprophytic mold phase in environment & parasitic yeast phase in host:
-Striking adaptation to permit growth & survival in mammalian host
-Thermal dimorphism-grow as mold at <30C as yeast at 35-40 C
*Candida albicans (thrush), Coccidioides (valley fever)

mold form in plant host, yeast form in environment

The Morphology of Coccidioides
a. Free Arthrospores
b. Septate Mycelium
c. Arthrospore formation
d. Disarticulation
e. Immature Spherules
f. Endosporulation spherule (mature)
g. Free endospores
h.Rupture spherule

A. Coccidioides immitis- filamentous colonie isolated from patient's sputum
B. immature and mature spherules in liver tissue from mice inoculated with the isolated filamentous fungus.
C. Histologic section with Gomori-Grocott silver impregnation

a. Gamete release 1N
b. Fertilization 1N+1N
c. Zygote 2N
d. Young sporophyte 2N
e. Zoosporangium (Mitosporangium) 2N
f. Resistant sporangium (Meiosporangium) 2N
g. Meiospores 1N
h. Sporophyte 2N
i. Male gametangium
j. Female gametangium
k. Male gametes
l. Gametophytes 1N
m. Female gametes

-Many have sexual & asexual phases
-Sexual phase: hyphal structures- Gametoangia intertwine or fuse, forming sexual spores
-Asexual phase: form spores or conidia (reproductive units)

-Asexula reproduction by fission (splitting) budding
-Budding: daughter cell formed by parent cell-bud formed by small outpouching of cell
*Bud may separate from original cell or remain attached. Chain of buds may form if they remain attached. forming pseudohyphae (pseudomycelia). Each cell can form up 24 buds.
-SEXUAL reproduction in some yeast. Produce several types of spores (ascospores). Type of spore produced useful for yeast ID.

-Most yeast nonpathogenic, but opportunistic if host becomes immunosuppressed.
ex: Candida, Malassezia,

Commensal Yeast of Humans:
normal flora or skin & mucous membranes (mouth)

Dandruff & seborrhea (large flakes & itchy red area around scalp)- Caused by Pityrosporum (malassezia)

Zinc pyrithione, ketoconazole, Selenium- sulfide in dandruff shampoos inhibit yeast growth & some help inhibit cell turn over.

on plates; molds & yeast colonies cultivated in manner similar to bacteria, but often slower to grow.

Because fungi and bacteria compete, selective media favoring fungi is used inhibits many bacterial due to osmophilic & acidophilic environment

mold can be studied during growth, without disturbing vegetative & reproductive structures.

C) Eukarya

C) Bothsexuallyandasexually

C) Saprophytic

B) Decompose organic matter to release carbon and nutrients to other organisms

D) Mycorrhizae

D) A ll of the above

A) Chytridiomycota

A) Reproducessexually

D) Ascomycota

C) Yeast

D) Meiosis

A) Conidia

D) Ascomycota

D) Ascomycota

A) Basidiomycota

D) A ll of the above

B) Basidiomycota

A) True

A) True

B) False

A) True

A) True

A) True