Post #2: Week 2 of Zebrafish Research Complete

Week two is now finished, and the data has been very exciting in terms of supporting my project advisor and I’s hypotheses! By quantifying phenotypes on a spectrum from normal to severe, I was able to generate mathematical support for the observations I have made thus far. Instead of just describing the trends I have seen qualitatively, I can now run statistical tests and provide charts that further demonstrate how the trends can be quantified. At this point, I have a lot of data and a lot of photos to analyze, so going forward I will be taking time to go through the information while completing my final week of experimentation. It is clear that I will need to take time after the actual lab work is complete to finish going through this data, writing a scientific-style paper, and making my final conclusions, but for now I can talk about what I accomplished in week two.

This week was largely focused on me gaining experience running the experiment, simply with fewer treatment groups so I could spend time working with the microscopes and taking photos for later image analysis. I feel much more confident about working in a laboratory setting and understanding the factors that go into creating and conducting an experiment, as well as staying organized materials-wise and lab notebook-wise.

In terms of the experiment set-up and data gathered, my project advisor and I decided to just run a control group and four treatment groups. Two groups were treated with 1.25% ethanol, one at 2 hpf and the other at 4 hpf, and the other two groups were treated at the same time points with 1.5% ethanol. This way, we could analyze a “low” dose and a “high” dose while also comparing different time points. I gave all of the surviving embryos phenotype rankings (either normal, mild, moderate, or severe based on characteristics assigned to each level) at 24, 48, and 72 hours after fertilization. I also conducted the same heart rate measurements as week one so that eventually I will have three weeks of data to compile into one bar chart. The final data piece I will have from this week (after I have a chance to photograph the embryos) will be measurements of their blood vessels. Just like the bar chart, I will be able to compile my phenotype rankings and blood vessel measurements from each week of experimentation, creating a larger sample size that can be used in statistical analysis and charts.

While I haven’t been able to photograph the week two groups yet, I did finish photographing the week one groups, and without even measuring I have already observed differences between groups. Larvae that were treated with larger doses of alcohol (in the 1.5% and 2% groups) have more severe and a larger amount of deformities, and in some groups the survival rate was so low I had only 2-4 fixed embryos available to image versus 5 with extra remaining in the 0% and 1% groups. I have not looked closely at differences between dose time points yet, but in week two I did notice that embryos treated 4 hpf had lower heart rates compared to 2 hpf. Going into next week’s analysis, I will definitely keep these initial observations in my mind as I conduct more quantitatively based assessments!

My project advisor and I are thrilled with the results of these experiments and hope that the final week will be just as successful as the first two have been. Next week will be very busy with image analysis, photographing week two larvae, and conducting the final round of experiments, but it will be an exciting way to finish off the lab work part of my project. I’ll be back next week with my third update–I’m looking forward to this final “fin-tastic” week in the lab, and hopefully I will have some compiled data and preliminary conclusions to share with you all by the end of it!