TRAIN Scholar Justine Horton's Blog

Hi Everyone...This week was easy breezy. My morning class was canceled on Wednesday, so I could sleep in for the first time since starting the semester. Regarding TRAIN stuff, I'm working on entering my data in Excel and interpreting it. It might just be me, but working with Excel is exhausting. As a small experiment, I replicated a process I did when I first started TRAIN. I prepared a plate with S.A. and added an antibiotic susceptibility disk dipped in a honey solution. The next time I come in, I'll measure the circle around the disk where no bacteria grows.

Hi Everyone, This week, I attempted my very first two-fold serial dilution. I was excited about this experiment because it's the next step in determining the effect manuka honey has on Staphylococcus aureus. It's also something I've never done before. It did require a few YouTube videos, but eventually, I understood the concept and what I was supposed to do. Since this is my first time doing this procedure, I consider it a rough draft. My main focus was technique. Ultimately, I noticed some things I'd like to tweak in the future, but it wasn't bad. Next week, I plan on doing another serial dilution with the corrections included.

Hi Everyone, In the lovely picture above, I compare suspended bacteria to a "standard" called 0.5 McFarland standard. It's supposed to help guestimate the amount of colony-forming bacteria per milliliter. IT HAS BEEN A SIGNIFICANT PAIN IN THE BEHIND. First, it took a lot of work to understand exactly what the McFarland standard was. Josh and I tried ignoring it (1. because we didn't have it, 2. because what is it?), but it kept popping up in the research articles I had been reading. Eventually, we decided to ask our nearest microbiologist, Dr. Robinson. Turns out she also had no idea what this "standard" was. So we had it ordered, just to see that it's a little tube and card (smh). I don't think it made a significant difference in my research. However, for the purpose of science, it was nice to have. Based on the standard, there is around 5x10^5 colony forming units/ml in the bacteria tube.

Hi Everyone, This week, I focused on my experiment's optical density part. Unfortunately, when I came in on Monday, I discovered the liquid had evaporated sometime over the weekend. I had to make a new sample, increasing the amount of media in each. On Thursday, I took the optical density of the new sample. It showed that all three types of honey inhibited growth. Manuka Honey 1 had the most potent MGO concentration and had the least growth. MGO, or methylglyoxal, is the compound accredited for honey's antimicrobial properties. The new sample showed evidence of cross contamination in the control well (media), so I'm testing the media to see if the whole bottle is contaminated. The next step is determining the minimum inhibitory concentration with a two-fold dilution.

(Lab's very own pink drink) Hi Everyone, I had a great week with my experiment. I am working on another process to measure the effect of Manuka honey on Staphylococcus aureus. I plan to use broth microdilution, typically used in microbiology, to determine a minimum inhibitory concentration. With this in mind, I'm hypothesizing that if Manuka honey inhibits the growth of S.A., then at some unknown concentration (discovered in the microdilution), the bacteria cell count will dramatically decrease. This week, I diluted each honey in 100ml of DI water to create a "stock solution." For a different test, I set up a microplate with wells containing variations of Muller Hilton Broth, S.A, and Honey's. I used a microplate photometer to measure absorbance. This is similar to the last test I did, but we're trying to eliminate some of the problems from that test.

Hi everyone, This week, I started simple. Monday, I took the optical density of my samples(media+SA, HG+SA, HM1+SA, HM2+SA) after 96hrs of incubation. All samples exhibited an increased optical density. These are different from the results we were looking for. I hypothesized that the HM1 and HM2 would inhibit the growth of Staphylococcus Aureus. Had I been correct, the densities would've decreased in HM1+SA and HM2+SA while increasing in Media+SA. However, I'm still optimistic because, despite growth all across the board, HM1+SA and HM2+SA had the smallest increase. The rest of the week, I spent time preparing for another test, hoping to decrease the technical issues I had with the spectrophotometer.

(Mueller-Hilton Broth) Hi everyone! My project this semester is testing Manuka honey as an antimicrobial. It's more complex than my experiment last semester, as I plan on measuring the effectiveness with more processes. Last week I made Mueller-Hilton Broth to grow the bacteria in. I grew multiple samples of Staphylococcus A. this week. Josh and I decided to start with the basics before diving into the complexities of my experiment. I'm working on the best way to dilute and transfer honey into the MH Broth. I used the spectrophotometer to measure the optical density of my samples. The idea is that the optical density will decrease if the honey inhibits the growth.