Lab Day 4

Lab Day 4

Results and Conclusions for Lab Day 3:

• Glucose: Positive, 
• Lactose : Positive (because there were gas bubbles)
• Sucrose: Negative
• Maltose: Negative
• Therefore our unknown can ferment glucose and lactose

• Starch Agar: Negative, therefore our unknown bacteria does not hydrolyze starch.
  

• Casein: Negative,therefore our unknown bacteria does not hydrolyze casein.
  
   

• Lipid (Fat): Negative
• 
• Gelatin Liquefaction: Negative, therefore our unknown bacteria does not hydrolyze gelatin.
  
• Indole: Negative, therefore our unknown bacteria does not use tryptophan as a source of energy.
  
• Methyl-Red: Negative, therefore our unknown bacteria does not ferment glucose via mixed-acid fermentation.
  
• Voges-Proskauer: Positive, therefore our unknown bacteria can ferment glucose via butanediol fermentation.
  
  
  
• Citrate: Negative, therefore our unknown bacteria cannot utilize citrate as its sole source of carbon and energy.
  
• Nitrate: Negative, therefore our unknown bacteria is unable to reduce nitrate ions to either nitrite ions or nitrogen gas.
  
• Triple Sugar Ion (H2S Production): Negative for H2S production and positive for ability to ferment glucose.
  

(our tube is on the right and isbeing compared to an uninoculated tube which is on the left)

• Urea: Negative, therefore our unknown bacteria cannot hydrolyze urea.
  
• Catalase: Positive, therefore our unknown bacteria uses the enzyme catalase to quickly break down H2O2 into water and O2
  
• Oxidase: Negative, therefore our unknown bacteria does not have cytochrome oxidase
  
• Litmus: Positive
  
   Left: our litmus test after one day incubation.
  

Right: our litmus test (middle) after one more day of incubation.

Experiment: Selective and/or Differential Media

Materials:

• Blood Agar plate
• EMB Agar plate
• Mannitol Salt Agar plate
• MacConkey Agar plate
• Phenylethyl Alcohol (PEA) Agar plate
• working stock of unknown bacteria
• inoculating loop

What we did and why:

What: (pictures will be shown in the results and conclusions in the next post)

1. we inoculated the blood agar plate

2. we inoculated the EMB plate

3. we inoculated the mannitol salt plate

4. we inoculated the MacConkey plate

5. we inoculated the phenylethyl pl-e

6. we placed them all in the incubator to grow overnight.

(results will be posted in next post)

Why: we did this experiment to isolate and differentiate from different types of bacteria (which will be specified in the results and conclusions in the next post).

Learning how to perform these tests will give us the ability and knowledge that we need to identify and know what to look for in bacteria.

Experiment: Testing Antibacterial Medicines

Materials: 

• Mueller-Hinton agar plate (2)
• individual antibiotic disks in cartridges
• forceps
• sterile cotton swabs
• working stock of our unknown bacteria

What we did and why (pictures will be shown in the results and conclusions of next post)

What: 

1. first we divided both of the agar plates into 4 quadrants per plate so 8 all together

2. next we inoculated the agar plates with our unknown bacteria from our working stock

3. we placed 8 different antibiotic disks, each one had their own quadrant 

4. we labeled each quadrant with the name of the antibiotic that was in and placed the plates in the incubator.
We labeled them:
Red
1. Neomycin
2.Norobicin
3.Penicillin
4. Streptomycin
Blue
1.Erythromycin
2.Tetracycline
3.Amoxocillin
4.Oregano

Why:We did this to determine the sensitivity of our unknown bacteria to several antibiotic medications. This will also help us in the future to show us what makes a bacteria resistant or sensitive