11/29: Identified Unknown C!

Today in lab, we identified our unknown bacteria (C) is B. cereus.

Bacillus cereus Results of Tests:
Shape: Bacilli
Arrangement: Chained
Spores: Yes
Gram's Stain: Gram Positive
Motility: Motile
Capsules: No capsules
Nutrient Agar: Raised/Cream/Tan colored, Circular with irregular edges
Nutrient Broth: Raised/Cream/Tan colored, Circular with irregular edges
Gelatin Stab: Positive (liquid)
Oxygen Requirements: Facultative Anaerobe
Optimum Temperature: 30 degrees Celsius
Glucose Test: Results were yellow and therefore positive
Lactose: Red and therefore negative
Sucrose: Yellow-Positive-No Gas
Mannitol: Did not grow
Gelatin Liquefaction: Positive, formed liquid
Starch: Positive
Caesin: Positive
Fat: Positive
Indole: Negative
Methyl Red: Negative, high pH
Voges-Proskauer: Negative
Citrate: Negative
Nitrate: Positive
Oxidase: Positive
Litmus Milk Coagulation: Running Curd


We also worked on our yogurt project, and we were successful in growing the different brands of yogurt! Except for Chobani Greek Yogurt- It was the only one that did not grow, so next time, we will thoroughly mix it in with the milk to see if it makes a difference.

11/22: ELISA Test

Today in lab we did an ELISA test. ELISA stands for Enzyme Linked ImmunoSorbent Assay. It's a test that tests for the Human Immunodeficiency Virus which has antigens and may have antiserum which are antibodies.

11/17: Yogurt and UV light Results

We looked at the yogurt we made on 11/15. We successfully made yogurt! It was white and had a thick consistency. People tasted it and it tasted tart.

Also, we got the results to the UV-C light experiment and did not expect what we found. Our bacteria grew, so the UV light did not kill the bacteria.

11/15: Yogurt Lab and Effect of UV light on Bacterial Growth

In this lab, we made yogurt by doing the following steps:
1. Heated milk in the microwave for 7 to 10 minutes until it boiled
2. Added Probiotic Substances, Kefir, Yogurt with Live and Active Cultures
3. Mix together
4. 40 degree celsius environment
5. Wait for 7-9 hours
(results will be checked on 11/17)

We also tested the effect of UV-C light on bacterial growth. We did this by inoculating a agar plate with our bacteria and then we set the plate under the light for 30 seconds. We expect that it will kill the bacteria, and when we check the results, no bacteria will grow.
Dr. P did another test to check the effect of UV-C light on bacterial growth by putting bacteria in a glass water and put a special UV light pen in the glass (with water and bacteria). The UV light pen kills the bacteria making the water safe to drink.

11/10:Oxidase

Results for tests from 11/8

            Citrate: Negative for Citrate

            Nitrate: Positive for Nitrate

            Indole: Negative for Indole

Urea: Bacteria grew at bottom, and color was yellow which means it does not break down urea.

Antibiotic Test: To determine if the antibiotics kill our bacteria. The measurements determine whether the bacteria is sensitive to the antibiotic.

            Antibiotics that break down cell wall

1)   Penicillinà 0mm

2)   Vancomycinà 20 mm

Nucleic Acid

3)   Novabiocinà 29 mm

Protein

4)   Tetracyclineà 15 mm

5)   Erythromycinà 34 mm

6)   Chloramphenitolà 29 mm

7)   Neomycinà 20 mm

The next test we did was the oxidase test to determine if our bacteria has cytochrome oxidase, which is an enzyme. When we inoculated it, it turned purple, therefore it his cytochrome oxidase.