About Me: I am a math teacher at Burncoat High School in Worcester, Massachusetts. I am a Worcester native, and graduated WPI in 2022 with a Mathematics B.S. and a minor in Computer Science. I started teaching in fall of 2022, and thoroughly enjoy working with students to help them discover the joys and sorrows of mathematics. My greatest successes in the classroom are when students reach an “a-ha” moment. I enjoy creating problems nearly as much as I enjoy solving them, and mathematics provides the perfect opportunity to do so. In the fall, I will be teaching Algebra 1 and AP Statistics. I have also taught Algebra 2, Statistics, and Financial Literacy in the past. Beyond teaching, I enjoy programming (mostly in Python), reading (mostly recreational mathematics, theology, and literature), and hiking (mostly outside).
About the Lab: Shell Lab at WPI is a molecular biology lab studying how mycobacteria regulate gene expression and survive stressful conditions and antibiotics. The most notable mycobacterium is M. tuberculosis (Mtb), which is responsible for 7.5 million cases of tuberculosis a year, leading to 1.3 million deaths. When M. tuberculosis enter the lungs, the body does its best to rid itself of these bacteria, by subjecting the bacteria to hypoxia and low pH. You may think that all this stress would make the bacteria more sensitive to antibiotics, but the reverse is true – Mtb actually becomes less sensitive to antibiotics! The Shell lab is currently working on various projects related to the proteins in mycobacteria: discovering new proteins, figuring out how they work together, and most importantly, encouraging good health and wellbeing by furthering our understanding of a disease that ravages our most vulnerable populations.
Project Title: Investigating the Impact of a Novel RNA Degradation Protein (Sre) on Antibiotic Tolerance in Mycolicibacterium smegmatis
Weekly Updates:
Week 1: This week, I got to meet with the Shell Lab and Abbey, my RET co-conspirator and another in-service teacher. We joined lab meeting and learned about all the different projects the Shell Lab is working on. After completing lab safety training, we got our coats and headed into the lab to start our first M. smegmatis cultures! We cultured 4 strains of M. smegmatis – one wild type, which can be thought of as the “original” M. smegmatis, and three knockout strains, which lack the ability to produce Sre. After letting these strains culture for 24 hours, we checked the optical density of each culture to measure cell growth. There’s a neat little formula behind the scenes that relates optical density and the percent of light that is transmitted through the sample – here is a worksheet with one of the formulas and some guided questions! (I’d recommend using this once students are familiar with the idea of logarithms as inverse of exponents.) Next week, we will be able to test the efficacy of antibiotics against these 4 strains.
Week 2: Monday was spent normalizing our cultures so they would have approximately equal density – this is to make sure all of our different samples start on an even footing. We wouldn’t be able to do much comparison if our first sample had twice the number of cells as our third sample! Then we mixed up some 7H10 growth medium, threw it in the autoclave for an hour to sterilize it, and poured it into 25 different petri plates.
Tuesday we started our experiment proper. We are working with 12 cultures: 3 wild type with no erythromycin, 3 wild type with erythromycin, 3 knockout strains with no erythromycin, and 3 knockout strains with erythromycin. At different time points, we take “snapshots” of the cultures by diluting each strain down and plating it. In a couple of days, we will count how many colony forming units (CFUs) there are. With no erythromycin, you would expect the number of CFUs to increase during each time point – after all, there’s nothing stopping the M. smegmatis from growing! We expect the erythromycin to kill the wild type strain, and we’re looking to see how the erythromycin affects the knockout strains. This is especially true because we are using 2x the MIC (minimum inhibitory concentration – the lowest concentration needed to stop bacterial growth).
Work-wise, this involves a lot of dilutions! I typically fill about 96 1000µL vials with 180µL of media…my thumbs get a little sore, but it’s relaxing. Plating is a little more stressful, as we have to make sure none of our droplets touch each other. Then, Thursday and Friday, we counted our colonies to estimate how many CFUs there were in the original sample.
Week 3: Now that we have some experience running our experiment, on Monday we started six brand new cultures (3 wild type, 3 knockout) and created some more petri plates in advance. We will be using erythromycin again, but only at 1x the MIC. 2x the MIC killed off our M. smegmatis a little too well last week! On Tuesday, we discovered that a couple of our strains were growing much slower than the other strains, so we renormalized and started an additional culture to compare. After renormalizing, we continued to test M. smegmatis against erythromycin. As expected, the bacteria grows normally (and does not smell pleasant) without the antibiotic, but we saw similar lack of growth and cell death in both the wild type and knockout strains. I’m getting better at pipetting day by day, and my spreadsheet I created to streamline calculations for normalization is making our lives much easier!
Week 4: We started off the week plating one more no drug sample, as it seemed like the erythromycin had killed off almost all of the M. smegmatis… but we wanted to make sure of it by counting the CFUs. We also normalized our cultures. We were off on another week of testing the efficacy of kanamycin and erythromycin against M. smegmatis until the power went out for half an hour in our lab! We are unsure how this affected our experiment, but all of our agar plates were weirdly humid. This meant we had to dry them out before we could plate anything, which added another hour to our procedure. As expected…kanamycin works! We saw similar growth (or lack thereof) in both the wild type and knockout strains. We also presented our poster, and learned that whatever you think the font size has to be, double it.
Week 5: What a week! As our poster is due during Week 6, this was our last week of experiments. We decided to trial M. smegmatis against linezolid and kanamycin. We finally got into a groove (of course, during our last experiment) when it comes to timing, but the MIC of linezolid is so small that it was difficult to accurately pipette. This makes sense, as linezolid is a pretty powerful antibiotic that is used in wide-variety of drug-resistant infections. We struggled to find the best dilution to accurately plate, but I finally learned how to use a 96-well plate. It is so much faster than pulling out 96 Eppendorf tubes. We also made some new agar plates – unfortunately, our last one turned out more like slime as we waited a little too long to plate them.
Week 6: Coming soon!
Final Poster:
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