Lab Practical 2 Flashcards
SIM medium.
semi-solid medium, casein, animal tissue as a source of amino acids, an iron compound, and sulfur in sodium thiosulfate.
- Motility test (also Thioglycolate Broth). Positive test for motility is indicated when there is more growth outward from the central stab line.
- Indole test. bacteria with enzyme tryptophanase hydrolyzes tryptophan to pyruvate, ammonia (deamination), and indole. By adding Kovac’s reagent containing DMABA reacts with any indole present which turns red.
- -Blackening of the tube’s
medium (SIM tube) indicates positive
result.
-Sulfur reduction to H2S
- Not using thiosulfate as an electron acceptor for anaerobic respiration
-Not breaking down cysteine to pyruvate, ammonia, and H2S with cysteine desulfurase/
Thioglycollate Broth
-tests whether a microbe can survive in presence of o2 or not.
-No NO3 (nitrate) so no anaerobic testing possible
-Semi solid medium containing an O2 indicator Resazurin (red in O2).
-growth away from stab line determines motility.
Thioglycollate conclusions
1. Obligate aerobe
2. Obligate anaerobic
3. Facultative anaerobe
4. Microaerophile
5. Aerotolerant anaerobe
- Growth only at top, no fermentation.
- Growth only at bottom, killed by O2. Only fermentation
- Growth all over the tube but better at top for more ATP. can do fermentation and aerobic respiration.
- Need O2 but at lower levels, growth better just below the surface. Only aerobic respiration.
- Growth all over the tube but not better at top. Only fermentation, but not killed by O2. There is still O2 at top can be seen by the presence of Resazurin (red at top)
Candle jar
Creates a microaerophilic environment.
Starch
Hydrolysis
-possess the enzyme
amylase, hydrolyze the polysaccharide starch to monosaccharides.
Sulfur Production (SIM Tube)
-Blackening of the tube’s
medium (SIM tube) indicates positive
result.
-Sulfur reduction to H2S
- Not using thiosulfate as an electron acceptor for anaerobic respiration
-Not breaking down cysteine to pyruvate, ammonia, and H2S with cysteine desulfurase/
-MR-VP (Contains peptone, glucose, phosphate buffer)
-Methyl Red
-Solution in the tube
turns red after adding
methyl red. The red
indicating a pH of 4.4 and yellow at pH 6.2
-Red color, sign of glucose fermentation to
stable mixed acids.
Possible endproducts lactate, CO2, Hydrogen gas
-MR-VP Broth
-VP (Voges Proskauer)
-when VP reagents A and B are added
-tests for fermentation of glucose but quickly converting their acids to acetoin.
-If either can or cannot ferment glucose
to acetoin. The reagent oxidizes acetoin (turns red) when present.
Nitrate Reduction
-when using nitrate as an electron acceptor for anaerobic respiration.
-After adding the reagents,
A and B the nitrate tube did
not change color (pink or red, nitrite present) (nitrite no
present) so proceeded to
add a pinch of zinc dust
and still no color change to pink
(no nitrate present for zink to
interact).
-able to reduce nitrate
to a compound other than nitrite like
NH3 or NO
Salt, Acid,
Temperature
- SALT——-TSA with
10% NaCl plate. Either grows or doesn’t - ACID——-TSA at pH 4.5. Either grows or doesn’t
- Temperature—–TSA plate
placed in the high
temperature (45° C)
incubator. Grows or it doesn’t
Catalase test (TSA plate)
Adding a few
drops of 3% hydrogen
peroxide.
- Tests for enzyme
catalase which can convert hydrogen.
peroxide into water and gaseous
oxygen.
- Positive if creates bubbles (O2)
Oxidase
-Whether it has an electron transport chain with cytochrome c oxidase
-The swab burns into a light purple color when positive.
-Brown otherwise.
Simmons Citrate Utilization
-Either growth or no growth
and did it turn blue in
color. The blue color change from green (pH 6.9 roughly neutral) indicates a pH of 7.6 (+).
-Ph indicator Bromthymol blue.
-Tests for presence of citrate-
permease which uses citrate
as its sole source of carbon.
-Citrate is converted to pyruvate in the presence of the enzyme.
-Bacteria that survives in the medium convert ammonium phosphate to ammonia (NH3) and ammonium hydroxide (NH4OH), which alkalinize the agar (changing from green to blue)
Phenol Red
Tubes
phenol red tubes
(lactose, glucose, mannitol,
and arabinose) turned yellow (positive) and contained gas in the inverted Durham.
-Positive test ferments carbohydrates to acids and gases.
-Pink indicates protein metabolism (raises the pH ammonia)
Urea test
Testes for the presence of the
enzyme urease. If hydrolyzes
urea to ammonia and CO2 will turn the pH
indicator phenol red to pink color.
Spirogyra
rhizopus
aspergillus, penicillium
Cestodes
Nematodes are multicellular organisms.
Trematodes
hyphae and mycelium
Cestode, in view the SCOLEX (head of tapeworm which attaches to gut wall
-Proglottids, segment of the body that contains both female and male segments that produce eggs.
Protozoans (paramecium and amoeba)
trypanosomes in blood (has flagella)
Slime mold (protista)
