Experiment 2

Lab Description: How to Streak Bacteria/ Make Cultures

Lab Journal:

Day 1: Assuming this does not follow directly from experiment 1, I would have had to prepare agar plates specifically for this experiment. Both halves of this lab use LB agar plates, which are the powder needed to mix with water to create the concentration required for the Petri dishes. If you'd like to know how I made them, please take a look at Experiment 1. 

Day 2: After making the necessary Agar plates, the rest is relatively simple. We will first need to follow the first experiment. Here, we are making cultures using bacteria that are growing around the house. A first step would be to find things to streak on the plates, such as my hands, my hands with gloves on, some leftover salmon, water from the sink, etc. Next, we would need to put them on the agar plates. This was on a case-by-case basis; for example, with my hands and gloves, I dragged my finger gently over the agar's jelly-like surface to avoid breaking it. For the leftover salmon, I used a Q-tip by gliding it across the surface of the smoked salmon in the fridge, then applied the same side of the Q-tip on the agar surface. For the water in the sink, I pipetted some with a 100 microliter pipet and ejected the water onto the agar's surface. I also added control to make sure that there wasn't any contamination in my swabbing and one with alcohol(but this one just killed off bacteria and did not yield anything). After, I closed all the agar plate covers and let them sit on my desk. 

Day 4: Since day three did not seem to have noticeable results, I skipped that day. two days after swabbing, I noticed some spots were beginning to become prominent, and some growth was occurring. The side with my hand started to have many colonies of bacteria in concentrated places where I dragged my finger. The glove side on the same plate, however, did not yield any results. The side with the salmon did have one or two small colonies that were popping up, and the control had nothing on it. The alcohol side also did not show any results, and the water also had (seemingly) no results. 

Day 5: It seems that I had made a mistake by saying that the water did not yield any growth. At the very edge of the plate, where some of the water did indeed leak to, a few smaller colonies were growing. The hand colonies were also increasing rapidly, showing different shades of yellow-colored colonies. The salmon colonies were also changing; however, there was a hint of smokey white in one of them. Other than that, the rest of the colonies were all growing, with the exception of the control, glove, and alcohol halves. 

Below: Close up of Water colonies and close up of control(showing no growth)

Day 6: Growth was all continuing as usual. The water half of the petri dish was growing colonies in differents spots, but it was still in it's appropriate side of the dish. The only difference was that the salmon colonies were starting to create mold. This may be because I accidentally swabbed too hard with the Q-tip in the beginning, meaning there was probably a small piece of salmon that got picked up and placed on the agar plate. 

Day 7: Today is the last day of the growing colonies. All of the bacteria were growing accordingly, but just larger. At the end of these 7 days, I had come to conclusion that the Alcohol and glove sides of the petri dish yielded no colonies because they were disinfected, which impedes bacteria to grow. To add to that same point, the control also did not grow anything, thus means that the environment and my protocol to disinfect everything in the experiment meant that there wasn't any contamination.