Author Archives: Rachel Estrella

If You Don’t Know, Now You Know

This summer has been an amazing experience. I had no idea that I would learn as much as I did when I first started, and I am so glad to have developed a better understanding for the world of science and found my place within it. And I am so thankful to have done it alongside such wonderful people in my lab and in BSURF, thank you all so much!

One of the biggest things I learned or came to realize is how big the world of science is. From the faculty talks, chalk talks, and the poster session I got to hear about the incredibly diverse and important research brilliant people are doing just here at Duke. Previously I had this notion that once you really get fundamental understanding of a topic, you just move on. But this summer I learned there are always more questions to ask and always new perspectives to take. I learned this while working on my own research project, as I needed to approach my problem differently and ask new questions as I learned more. I also learned that science is an incredibly slow process. Everyone says it, but you don’t fully understand it until you’re waiting for the results you really really want to see and they don’t come. But luckily, research doesn’t stop just because BSURF is over. These eight weeks have been a great introduction, but there’s so much more to discover!

The biggest take away for me this summer was that the research you are doing is useless unless you communicate it. Before this summer, I often overlooked this portion of research and thought hands on work in the lab was most important. But I soon realized that posters, papers, and presentations give your work meaning and direction and make it impactful. I am so grateful for the opportunity to both observe and practice this communication of science, and I hope to only get better from here. Again, I am so glad I was apart of this program this summer. I will surely never look at science or fruit flies the same again.

I Know Why the Caged Bird Sings

One of my favorite parts of the program this summer has been hearing about the work that so many renown scientists are doing here at Duke. It has been really wonderful getting personable insight into the biological field of research, stories of unique paths into research, and advice for those of us just starting out. I have been able to take away so many words of wisdom and cool stories from every talk, so I want to thank the faculty for their time and willingness to share their stories with us.

A presentation that really interested me was by Dr. Steve Nowicki who talked to us about categorical perception and the evolution of animal signals, focusing in on birds. I feel like as humans, we are so consumed by our own perception and how we view the world that we forget all organisms on the planet perceive the world in their own special way. He talked about how female birds while choosing mates categorically sort out information that is relevant to the fitness of the male birds. It was also really interesting to me how a single note change in song or a slight discoloration in the beak could be consequence of a long combination of environmental stressors and genes that would ultimately affect female choice.

This talk was really interesting to me because the topic intersects a lot of things I enjoyed learning about in class, like sexual dimorphisms and sexual selection in biology and perception and attention in neuroscience. This really unique research shows me how you can find your own niche in biological research and ask questions only you would think to ask, while investigating something you really enjoy. I’m looking forward to learning more from professors in the biology department about their research.

Abstract: How does DIP-alpha contribute to the development of the olfactory circuit in Drosophila?

The assembly of neural circuits is a highly complex process that has not yet been fully understood. The olfactory system of Drosophila offers an excellent model system to better understand this organization, as 50 classes of olfactory receptor neurons (ORNs) synapse with their target projection neurons within 50 class-specific and uniquely positioned glomeruli in the brain’s antennal lobes. By analyzing the antennal transcriptome data from four stages of the antennal lobe development, we have identified a gene family of interest containing DIPs and DPRs, which are known to have homophilic and heterophilic interactions that regulate the assembly of several neural circuits. Through an RNAi mediated screening of this Ig Superfamily, we hypothesized DIP-alpha is important to the organization of ORNs into specific glomerular formations via axon terminal guiding.  We used several genetic methods to test this hypothesis, including the downregulation and knockdown of DIP-alpha in all ORNs and explored glomerular formation in various DIP-alpha mutant flies. In addition, we used genetic labelling techniques and antibody staining to identify the expression pattern of DIP-alpha. Although we were unable to identify a clear expression pattern, our results from the glomeruli structures in flies where the function of DIP-alpha was genetically perturbed suggests that DIP-alpha is important to glomerular formation. Further study of its roles in class sorting will give us more insight into the molecular basis of this complex circuit assembly.

Fly With Me

A day in the life of me in the lab is like a 90s sitcom, where you can predict what’s going to happen but each episode brings it’s own laughs. Each day in the lab is essentially a step in my experiment process, with it’s own victories and defeats, which keeps me looking forward to what each day brings.

First things first, I get to lab and check on my fly babies. I have around 20 vials of flies to take care of so I go in and make sure they’re alive and well. If it’s getting too crowded or if they need new food I flip the flies into new vials. I then collect whatever line of flies I need for dissection and take them to the dissection scopes. Dissection has come to be my favorite part of the experiments I do. After a lot of practice, I think I’ve gotten to a place where fly brain dissection has become far less stressful and actually enjoyable. I grab my forceps and the buffer solution and dissect the brains I need to, at a rate of about 15 flies per hour. I have to dissect a line in about an hour to prevent the brain tissue from deteriorating. I then fix the brains in a PFA solution and wash them thoroughly.

The next step in the process is antibody staining to target the DIP-alpha expression in the brains. We usually put the brains in primary antibody overnight in a 4 degree C fridge, so if this is where I am in the process on a given day, I will come in and get the brains from the fridge and wash them thoroughly to remove the primary antibody. After that I’ll put them in secondary antibody, which will ultimately give us the fluorescence we need to identify DIP-alpha expression under the microscope. This staining process occurs for 2 hours at room temperature and is followed by yet another cycle of washing.

Finally, all the dissection and staining and washing leads up to the defining part of the experiment: imaging. This is where we can see if any of our work paid off. This part involves mounting the brains neatly on a slide and using a confocal microscope to view the brains and any specific signals from the antibody staining. I take pictures of the data and use the results to determine which flies I need to dissect next, what antibody I should change, and start the process all over again.

Microglia and Mice and Disorder, Oh My!

Going into week four of BSURF I was so excited to hear about all the great work my peers are doing in the lab. As the summer continues, I’m gaining a more holistic view of what science is and what scientific research looks like. From this week alone, I have learned so much about what biological research here at Duke encompasses, from studying the ultrasonic vocalizations of mice in helium to making mutant enzymes to degrade plastic. I would just like to thank everyone for sharing the stories of their research this week, you all did a great job!

One project that really stood out to me was Kat Beben’s. She is working in Dr. Staci Bilbo’s lab this summer and is characterizing the development of microglia in the anterior cingulate cortex (ACC) of mice. Kat outlined the full goal of Dr.Bilbo’s lab: understanding the prenatal factors (genes, the environment, maternal stress) that can lead to autism spectrum disorder. Through previous research, the lab has come to identify microglia, the immune cells of the brain, as being important for synaptic pruning and refinement, making their disfunction detrimental to biological systems, notably resulting in an autistic phenotype, as shown in mice. The lab is asking if combined prenatal stressors alter this synapse formation and refinement. They are specifically looking at the ACC, since this cortical region is involved with emotional processing, learning, and memory. As Kat works to characterize the normal microglial development in mice, hopefully we can better understand how various stressors disrupt this pathway.

I found it really interesting how the meticulous study and manipulation of such a small system can have such a large and significant impact. In my experience in learning about neuroscience, the function and influence of microglia has often been overlooked, but it is clearly not to be taken lightly. I really admire the work this lab is doing, and it reinforces to me the importance of biological research. As Dr. G reminds us, science isn’t just moving colorless liquids from one vial to the next, although I’m sure we’ve all done this. It’s about discovering more and more about our universe, one question at a time. I can’t wait to see what we uncover!

Trust the Process

When most people talk about flies, it’s usually in disgust followed by swift swatting motions. But when Dr. Pelin Volkan talks about flies, it’s with fascination followed by swift strategies to answer the next scientific question. My principal investigator first started studying molecular biology and genetics at Bogazici University in Turkey and began to get interested in neuroscience. When she went to the University of North Carolina for her PhD, she began to study the nervous system of Drosophila and continued this study during her post doc at the University of California, Los Angeles. At the time, the olfactory system of Drosophila was just being described and peaked Dr. Volkan’s interest in the development and evolution of brain and behavior. This influenced the main work she does now at her lab at Duke, asking how a hard-wired system maintains plasticity, ultimately, what are the nature and nurture factors that influence this organism’s brain?

Dr. Volkan’s approach to doing science is really quite insightful. She notes that you almost never stick with the plan and that your study and goals will change with the problems or circumstances that you encounter. And importantly, chance favors the prepared mind. She told me she really enjoys the academic environment as you are frequently bombarded with new perspectives that open up new questions. She notes that science is not static, it’s progressive, and we need innovative and creative thinkers to continue to propel science forward. Dr. Volkan describes the most rewarding part of doing science is getting a crystal clear answer to one of these questions, but as she explained to me that very rarely happens.

But she also enjoys the chase, the process of discovery and the thrill of seeking answers. This is what drives her, and many other researchers, to press on, failed experiment through failed experiment to find an answer. She enjoys relaying this notion of taking joy in the process to her students in her favorite class here at Duke, her lab course in which students take on projects connected with the lab and experience what it’s like to do science. I am so grateful for this experience to work with Dr. Volkan who has already inspired me to press on and trust the process. 

Lord of the Flies

When I was placed in the Volkan lab and took a tour back in May I was fascinated, but I had my doubts. What could we possibly learn about human neurobiology by studying Drosophila? Can I get a handle on these complex biological techniques in 8 weeks? How am I going to dissect a fly brain??

Upon arriving, my mentor Qichen really helped bridge the gap between the work we plan to do in the lab and my understanding of neuroscience. He explained to me that the human brain as we know is an incredibly complex system. The brain consists of around 80 billion neurons and 100 trillion specific synaptic connections, making the study of its development and organization highly complicated (Barish et. al., 2018). He explained to me that this makes Drosophila the ideal model organism and its olfactory circuit the ideal system to study to get a better understanding of how neurons sort and make very specific connections to allow for the proper function of the system. Through previous research, our lab has identified a family of proteins dubbed DPRs, defective proboscis response proteins, and their binding partners called DIPs, DPR interacting proteins, to be essential for regulating the positioning and structure of glomeruli in the olfactory system (Barish et. al., 2018).

This summer, my project will focus on the role of one specific protein in this family, DIP-alpha. My major goals are to discover its expression pattern, in specific olfactory receptor neurons, and to genetically perturb its function. The first goal will be accomplished using genetic labeling and antibody staining of both the Drosophila antennae and brain, and the second goal will be attained by down-regulating DIP-alpha in specific classes of olfactory receptor neurons to investigate what happens in the protein’s absence. So far, I have been honing in on my dissection skills and familiarizing myself with the staining and imaging process. In the coming weeks, I hope to get some fascinating data that leads us closer to understanding the development of this circuitry. And if I don’t, at least I can dissect a fly brain!


Great Expectations

Summer is finally here, and along with it comes the heat, humidity and high, high hopes. As I begin my research experience in the Volkan lab, I hope to gain a new understanding of scientific research, take a closer look into the field of neurobiology, and find my place within it.

For the next 8 weeks, I expect to do science. This being my first research experience, I have never done science experiments outside the scope of classroom objectives. I have always walked into chemistry or biology lab with the goal of getting the lab done and getting the answers right. I am excited this summer to take a step away from that and begin to reason and question like a scientist. With the help of my mentor, I am already beginning to understand for my research project the important questions to ask that will lead to important conclusions or even more interesting questions. In essence, I would like to begin to think about science in a refreshing and novel way.

I also expect to learn more about the field of neurobiology and how I would like to be involved with it. I have always enjoyed learning about neuroscience in the classroom but I would really like to see how scientists go about uncovering the mysteries of the brain. In the lab, our model organisms are Drosophila, fruit flies, and we look at the mechanisms of olfactory neuronal development in the hopes of gaining some insight into the development of the complex circuitry of the human brain. Within the first week, I have already found it very interesting how scientists have approached the difficult subject in such innovative ways and employed genetic techniques to manipulate biological systems to learn something new. While working in the lab, I hope to use these techniques myself to contribute some meaningful data to the incredible work that those in the lab have already done.

Finally, I expect to discover how I fit into the world of research. During her faculty talk this week, Dr. Sheila Patek posed some important questions for us to consider that I would like to answer myself, such as what is important to me about research and what it means for research to have an impact. I hope through my work this summer, I come to find meaning and fulfillment in the lab, alongside my peers.