S-STEM Scholar Rolanda Bell's Blog

I was completing inhibition assays on my lil' Lactobacilli. I was trying to determine if they could inhibit the growth of a food pathogen like E. coli. So, I got a petri dish filled with MRS agar, dug a well, and inserted 500 microliters of MRS broth inoculated with a 24 hour, undiluted culture of each of the Lactobacillus species, acidophilus, plantarum, and rhamnosus. Then I spread lil E. coli around the top of each of the wells. All the research I read indicated that the two did not make good roomates, but what happened next could not have been anticipated. E. coli just had his run of the place. I asked the Lactobacilli what happened. They informed me that E. coli was nice but could be a little aggressive at times. It was difficult keeping the place tidy while he was around. They suggested that I leave them alone in the well  and then bring E coli by in a couple days. So I did. I left them alone in the well before I moved in E. coli. However, I was bamboozled! Lil' L

From previous conversations with Johnathan, I knew he was a numbers guy, so I decided to to ask if he could help me with my dilemma. You know what?...Johnny on the spot came right through like I knew he would. This idea is so amazing that I couldn't believe it. He suggested using a type of cohort analysis to calculate the missing part of the growth curve. My calculations indicated that I would miss the transition occurring around 16 hours. Johnathan suggested to get another culture started around 5:00 pm, and come the next day at 9:00 am (16 hours later) and record what I missed. Awesome...right? Turns out I didn't miss a thing after all.

I don't know how many of you have met our fellow STEM student Johnathan, but he is the tall guy with glasses. He's kinda funny, very nice, and super smart. I was chatting with him one day and realized that he was a mathematical genius. Which was convenient because I had a mathematical predicament. I was trying to calculate a growth curve for three species of Lactobacilli. However, after collecting some preliminary data and calculating a few estimations, I realized that I would miss an important change in my bacteria. Unlike E. coli, Lactobacilli take much longer than 10 hours to complete their growth cycle. After asking to stay after hours, I was informed that the lab had not been Rolanda proofed, so I couldn't stay pass 5:00 pm. Facing this conundrum, I decided to consult with Phoenix college's brain trust- Matt and Josh. They came up with the idea of monitoring carbon dioxide levels during the period when I wasn't there. Then I could use the data to