Author Archives: Jayden Cyrus

I began this program with goals of growth, and I have grown more than I could have imagined. When the pandemic started, I initially struggled with my curiosity in virtual lectures. Being in the lab, however, has helped me find my curiosity and passion again. From nervously awaiting experimental results to asking any question that I had, this summer let my passion shine through. While being sick close to the end of the program was a challenge for me, I still made a poster I was proud of, and I loved presenting to everyone. Despite past uncertainties about my career goals, I realized that I want to do science and am grateful that I found the career that excites me.

Beyond professional growth, I’ve also found time to grow personally. Specifically, I’ve grown in my confidence, which was another one of my goals at the beginning of the summer. While my confidence in my academic ability has improved, so has my personal confidence. Additionally, one of the most valuable aspects of this summer was working with Dr. Sherwood. Her kindness allowed me to be myself in the lab, so I could ask any question I had in a comfortable space. Dr. Sherwood and I were able to develop a great relationship, and her lab feels like home. I can’t imagine a more supportive PI or a more positive lab environment, which is one reason I plan to continue working with Dr. Sherwood in the fall. This summer has been amazing, and I’m so excited for my future!

Jayden Cyrus 

Mentor: Nina Tang Sherwood, Ph.D.

Department of Biology

The SPG4 (spastin) gene plays a role in microtubule severing, and when mutated in humans, it causes Autosomal Dominant Hereditary Spastic Parapelgia (AD-HSP), a disease that impairs mobility in the legs. Previous studies in Drosophila have shown that ubiquitous spastin deletion creates small, bunched boutons in the larval neuromuscular junction (NMJ) and motor defects in surviving adults. However, it remains unknown where spastin acts. We are testing the hypothesis that spastin acts in a specific tissue, such as neurons or glia. To test this, we are using CRISPR-Cas9P2 and a tissue-specific expression system to delete spastin exclusively in the glia and neurons of Drosophila. Additionally, we are examining flies with ubiquitous spastin deletion to control for the novelty of the Cas9P2 technology in Drosophila spastin. If Spastin is acting in a tissue-specific manner, the flies with the tissue-specific deletion will show the spastin mutant phenotype. In addition to studying the site specificity of Spastin, this study aims to test the effectiveness of Cas9P2 as a genome editing tool in Drosophila and contribute to the knowledge base of those studying AD-HSP.

Because Misaki Foster and I have been friends since we met last fall, I was bound to know something about her research before the chalk talk. While I knew she was working on mitosis in caterpillars, I didn’t fully understand her research until her chalk talk. I’ve always seen her passion for science, but to see her in action giving her talk blew me away! In addition to her passion and effective explanations, Misaki’s research in the Nijhout lab caught my attention.

When she said she worked with imaginal discs, I became even more excited about her research. I had seen them under the microscope in some of my first larval fly dissections, and they caught my attention as the spiral structures fluoresced red. In fact, I hadn’t heard of them before that moment when I asked Dr. Sherwood what they were. However, when Misaki mentioned that she was dissecting imaginal discs, I put together that these are a common structure among larval insects. Imaginal discs are small structures that begin inside the larva and emerge as a part of metamorphosis to become external structures. In fruit flies, there are multiple imaginal discs that will transform into the eye/ antennae, the legs, the wings, and more. Misaki studies the discs in caterpillars that will later become butterfly wings! 

She explained how her lab studies development from the imaginal disc to the wing, asking the question, how is organismal growth regulated? To answer this question, she is measuring how much mitosis is happening in the wing at a given stage of larval development! While it makes sense that mitosis would directly relate to development, it’s something I had never thought about in that way. Once she dissects, fixes, and dyes the disc, she looks at it under a microscope to score each instance of mitosis. Misaki uses the chromosome positioning to identify cells in which mitosis is occurring, watching out for the different phases, like anaphase. Once she has these numbers, she puts them into a program that identifies hotspot regions of mitosis, and this is how they will find areas that are growing the most during different stages! The idea of mapping out mitosis is a new concept for me, but it’s one I find intriguing. 

While Misaki’s project introduced me to new concepts, her explanations were logical and her presentation was amazing. As someone who uses flies as model organisms and sees the value of understanding larval development, I find Misaki’s project exciting and can’t wait to see where it leads! 

While every day has a different to-do list, two tasks remain consistent: collections and dissections. Every morning, we check our boxes of fly vials for the ones we need to collect from. With tons of crosses going at the same time, it’s hard to keep track. To collect the flies, we dump the vials onto porous pads that emit carbon dioxide to put the flies to sleep. Then, we can look at them under a microscope to see if they have our desired phenotype, genotype, and age! This process allows us to have flies with everything we need in their genotype by crossing lines that already exist. For example, with this method we can create lines with a mutated spastin gene, but only in their neurons! We can also make lines to control for the technology that we’re using; if the technology was causing a phenotype, then that could mean our spastin mutation isn’t causing the results we see. 

Aside from collections, we also dissect larva of interest. Because mutants with deletions in the spastin gene have bunched terminal boutons and tiny synapses, dissection is key for our lab to study different types of spastin mutants. Dissecting consists of placing a larva in a dish with pins in it. Using forceps, pins, a saline solution, a microscope, patience, and expensive tiny scissors, we pin the larva down and create “fillets”. We fix these fillets so that they remain stable while they go through several washes, solutions, and antibodies. Finally, we mount the fillets onto a slide so that we can look at them under the microscope with fluorescence. Recently, we learned how to “score” a slide, which means we count the number of terminal boutons on a particular muscle. Difficulties arise when boutons synapse on different planes of focus on the microscope, meaning they aren’t synapsing on the same muscle even though they seem to be in the same area. Despite having difficulties with scoring, I’m beginning to develop an eye for finding muscle 4 and counting the terminal boutons that we are interested in! 

In addition to collections and dissections, our days consist of working out crosses on the white board, talking with Dr. Sherwood about the science, or going through papers. We also recently started a PCR project to determine if some lines actually have spastin deleted from their genome. Even though it’s been a struggle at times, Shibani and I have learned a lot and have developed our skills in collection, dissection, paper reading, scoring, washing, staining, and more!

Shibani and I preparing potential spastin mutants for PCR

My mentor is Dr. Nina Tang Sherwood, a kind and caring professor of biology here at Duke! For her undergraduate degree, she went to UC San Diego with a major in BME. While her interests have since changed, she originally chose BME due to inspiration from her older sister along with interests in math and biology. Despite enjoying the classes, she didn’t find her passion in the actual BME research. She shifted to neuroscience after loving 101 in her junior year, and later focused on it for her PhD at Duke. Despite having two parents in science and a definitive love for research, it took her a while to find exactly what she wanted to study. From her first lab in physical chemistry to studying her passion for synapses, Dr. Sherwood’s path wasn’t a direct one. While studying axon guidance, the lab she was in happened to identify the spastin gene in a gain of function screen. Luck was on her side since spastin played a role in her true passion – synapses. Ever since, she has been studying spastins’ role in the synapse, realizing more questions to explore after each finding. In addition to research, she also found a love for teaching. While it was something she initially avoided, she now appreciates both the long term investment in a research project alongside the instant gratification of teaching. I find her journey comforting as someone who isn’t sure about their future. Dr. Sherwood’s path reassures me that we will find our niche, and that life will take us where we need to go. 

I was particularly interested in a funny story from earlier in her scientific career. She worked in a lab that studied arteries by using pig hearts, and it was the first day she got to watch one of the surgeries. However, she got something in between her eye and contact lens, causing her to tear up. Her mentor thought she was crying due to the surgery, making her embarrassed; she knew she could handle it and didn’t want him to think she couldn’t. Eventually crying it out, Dr. Sherwood got through the surgery. While she was telling the story, she was laughing about how it was a silly memory, which gave me some comfort. Even if we fail or feel embarrassed in the lab now, we have to remember that we’ll be able to laugh about it later. 

Lastly, we asked if she had advice for her younger self. “Don’t be afraid to ask questions and be less self conscious… just caring less about negativity from other sources and just doing the thing.” I think many of us can resonate with this advice. In fact, these were some of my goals before even applying to BSURF. I’m happy to say I have been asking all of my questions to Dr. Sherwood and have grown because of it. It helps that she is open to any question and creates a comfortable lab environment, but I hope to carry this trait into my future, even if the environment is more stressful. I hope we can all do our best to take her advice to heart, focusing on our passions and research, not negativity or self consciousness. 

Interviewing Dr. Sherwood gave me comfort about my future and insightful advice for the present. I’m excited to continue to learn from her, whether it be about science, life, or a life in science!

This summer, Shibani and I are working in the lab of Dr. Nina Tang Sherwood studying the spastin gene, which plays a role in microtubule severing. With a long history that began in 2004 when Dr. Sherwood’s lab identified the gene in a screen, the specific site of action of spastin is yet to be discovered. Previous studies consisted of ubiquitous mutation of spastin, which means every cell in the body had spastin missing or knocked down. Dr. Sherwood found that spastin null fruit flies have bunched, irregular synapses in the neuromuscular junction along with reduced motor function and lifespan (2004). However, we don’t know if this result was caused by the knockout of the gene in neurons, glia, or if it has to be ubiquitous to see this phenotype. Therefore, one of our projects is to determine where this deletion really matters in order to find the site of action of spastin!

To determine this, we have to make a bunch of complicated crosses. In our self efficacy program on Wednesday, we were asked to write a challenge that we needed to overcome in the lab, and I chose understanding crosses. I am happy to say that the next day I was designing my own crosses on the white board with Shibani! What is so complicated about these crosses is that you need so many factors in the final product and multiple lines to get to your desired outcome. What will set our final lines apart will be the tissue specific drivers, which make sure your mutation is only in the tissue type you want. We plan on using glial specific drivers, neuronal specific drivers, and ubiquitous drivers. Our next step will be to look at the neuromuscular junctions by dissecting larva! 

My first day of practice dissections was rough, and if I try to dissect for too long, I start to feel sick to my stomach. Dissections are especially difficult since larvae are tiny, so we have to use tiny scissors and dissect under the microscope. The hardest part for me is pinning the larva down, because the pins can slip in my forceps. However, after a little practice each day for a few days, I have strongly improved my dissection and am ready to do the real thing! After comparing the glial, neuronal, and ubiquitous knockouts, we hope to learn more about where spastin functions. I’m already proud of the progress Shibani and I have made with the support of Dr. Sherwood, and can’t wait to see where our project ends up!

My first dissection (left) vs my most recent dissection (right)!

Initially, I wasn’t quite sure how to verbalize my goals and expectations for the summer. I had so many responses running through my head; to learn about the science of my lab, to make friends, to get a head start on what could possibly be my future career field. After revisiting my application, I realized that my overall goal is to grow, whether it be personal, professional, social, or academic growth. I hope to grow in my confidence, explore my curiosities, gain footing in the world of research, and better understand the science of my lab to eventually arrive at questions of my own. As long as I grow and learn throughout the obstacles, I will have reached my summer goals! 

Even though it has only been two days, I’m loving my lab and have already begun working at my goals of growth. I’m studying in the lab of Nina Tang Sherwood, which uses fruit flies as model organisms to study the spastin gene. The spastin gene plays a role in microtubule severing, and humans with mutated spastin suffer from a neurodegenerative disease called Autosomal-Dominant Hereditary Spastic Paraplegia. Although spastin is exciting, we first have to learn how to handle the fruit flies! On the first day, we learned how to transfer them to new tubes, identify the sex, sedate them with carbon dioxide, identify mutations based on the phenotype, and look at them under microscopes. On the second day, we worked through one of Dr. Sherwood’s papers on fly spastin; it’s not everyday you get to read a paper, have the author explain it to you, and ask any questions you want! I’ve learned so much already and I can’t wait to see where I’m at when the summer ends. As my fly maintenance skills improve, I am excited to begin exploring the spastin gene and its neurological implications. I’ve been having fun learning with Dr. Sherwood, Shibani, and the flies, and am excited to see where this summer takes us!

Jayden and Shibani transfer their first fruit flies