Alina Moreno - Post 3

Hi everyone! Today I want to talk about a bioassay I conducted to determine if one of our colonies was still resistant to Lsph.

First, I prepared a 10,000 ppm Lsph stock, then made serial dilutions to create concentrations of 1,000, 100, 10, and 1 ppm. Then I used these stocks to create cups of concentrations 0.005, 0.05, 0.5, 5, 50, and 500 ppm. I made 3 replicates of each concentration. In each cup, I placed 25 2nd-instar larvae and added some food.

This is what the cups look like; the one on the left is the control (no Lsph), and the one on the right is the highest concentration:

This is what the setup looks like:

I checked the cups every 12 hours, counted the survivors, and collected the dead larvae in ethanol. At 48 hours, I ended the experiment and also collected the survivors in ethanol.

After analyzing the obtained data, we concluded the colony was still highly resistant to Lsph. The resistant and susceptible samples in ethanol were stored in a -80 °C freezer and can be used for future genetic analysis.