Second entry.

In my last report, I discussed my antibody staining project. As of last week, I have imaged all my fly ventral nerve cord samples using the confocal microscope. I used a software program to analyze those images, and discover the results! I spent most of last week making my poster for the Summer Research Institute (SRI) presentation.
 
Another project I worked on in the lab is setting up and monitoring genetic crosses. The ultimate goal of this experiment is to create flies with a genetic modification. These flies will then be used in behavioral experiments. My graduate student mentor, Clare, studies walking behavior in flies using the FlyWalker: an apparatus designed to allow the study (the walking behavior) to put the flies in a small chamber from which they cannot escape. The FlyWalker is accompanied by a software program that allows us to track the steps and other gait parameters of the fly’s walking. I spent much of my time in the lab during the spring semester going over the tracked videos to ensure the program had tracked the walking accurately.
 
Scientists have established that three neurotransmitters play a key role in walking: serotonin, dopamine, and octopamine. Researchers in the Mann Lab have already done experiments tracking the walking behavior in flies with one or two of these systems inhibited. The aim of the genetic crosses - I am setting up - is to inhibit all three neurotransmitter systems. When only one or two neurotransmitters are inhibited, there is a possibility that other neurotransmitters have redundant roles or may compensate for the loss. When these flies are ready, they will be walked using the FlyWalker and the data will be analyzed. The way the neurotransmitters are inhibited is by using the Shibire tool: a heat-sensitive tool that stops the formation of synaptic vesicles which carry the neurotransmitters. When the flies are heat shocked, formation of these vesicles stops. However, at non-heat shock temperatures, the flies behave like control wild type flies. Monitoring the crosses takes a large part of my day at the lab. Every morning, I check on the flies to see if there are new progeny, and to make sure they are not overcrowded. Additionally, most crosses require that the females are virgin females because female flies can store sperm. By selecting virgin females, we know that we are selecting female flies who will mate with males to create the exact type of progeny fly we want. Fly crosses normally take 10 days to produce progeny. The progeny are either used for experiments or used for another cross. I enjoy working with the crosses and being exposed to many different types of flies. It’s also always fun to find the progeny I’ve been waiting for!
 
In my last report, I mentioned how important collaboration is in science. One very interesting collaboration is between my mentor, Clare, and Columbia engineers. This summer, I have had several opportunities to accompany Clare, when she goes to meet with Tanya, who is a Columbia engineer and is great at developing ways to design assays for the FlyWalker, which Clare and other Mann Lab members want to test. Clare wants to design a chamber so she can study the behavior of flies crossing gaps. Tanya and Clare worked together to design an optimal chamber. While I was there, Tanya and Clare laser printed several chambers. It was very interesting to see how Tanya and Clare spoke about designing different aspects of the chamber. Tanya shared the engineering perspective, while Clare contributed the biology perspective. I am enjoying the opportunity to see this type of collaboration that highlights STEM fields being so much more interdisciplinary than they often seem at first.
 
Since my antibody staining project has reached its end, my goal for the next two weeks is to focus on my crosses. I have also been assisting other members in the lab with some of their projects. One project I am working on uses overlap PCR. I have really enjoyed seeing other researchers’ work because I am still exploring different areas of interest in biology. My other goal is to prepare for my presentation on July 29th at the SRI poster session. I am excited to present and see the work others in the program have completed.

This is the FlyWalker. It works based on the principle of total internal reflection.

Clare (left) and Tanya (right) with the new laser printed chambers!