My name is Alicia Ugenti and I am an undergraduate from Amherst College studying Biology and Sexuality, Women’s, and Gender Studies. Last year, I took a course in Developmental Biology and for the past three years, I have conducted research in the lab of Katerina Ragkousi, with my time now culminating into a thesis for partial completion of a Bachelors of Arts in biology with honors. I am using the embryos of the sea anemone Nematostella vectensis to study how epithelia form during early development. With the ongoing lockdown due to the COVID-19 pandemic, my summer research stalled. The virtual SDB meeting provided me with the opportunity to broaden my knowledge about developmental biology and the recent breakthroughs in the field. As this was the first SDB meeting I attended, I expected to learn more about different developing organisms and hear first-hand from the people who are doing the research. I was very excited to learn about organoids, which is a new topic to me and one I hope to apply in my future career as a physician-scientist. This meeting has allowed me to consider my work in the future and prospects for which I am most passionate in developmental biology. Based on my research interests and my background, I have chosen to highlight the following talks:
In the Satellite Symposium: Emerging Leaders in Live Cell Imaging Approaches of Developmental Biology, Vanessa Barone from UC San Diego spoke about her research using sea stars and sea urchins to investigate the conserved connection between cell-cell contacts and nuclear β-catenin. Barone found that the number of large cell contacts positively correlates with nuclear localization of β-catenin levels in both sea stars and sea urchins. Erica Hutchins from the California Institute of Technology used chick embryos to investigate neural crest development and concluded that dynamic ribonucleoprotein granules found in the cell cytoplasm (P-bodies) control a developmental epithelial-to-mesenchymal transition program via post-transcriptional target degradation. Finally, Hidehiko Hashimoto from the University of Chicago discussed how the dynamic integration of cell-cell signaling, force generation, and tissue remodeling controls zippering and neural tube closure in ascidian embryos. Hashimoto found that during neural tube formation and closure, there is higher myosin activity along the entire Ne/Epi boundary (neural folds) ahead of the zipper and lower myosin behind the zipper.
During the Presidential Symposium, Nicole King from the University of California at Berkeley talked about how choanoflagellates can transition into an amoeboid state when under stress. Cells appear to retract the flagella and become motile in a myosin-dependent manner. This work implies that the evolution of animal amoeboid cells may have arisen from a stress-induced response that is hardwired in a post-transcriptional regulation program. Valentina Greco from Yale University discussed how modifying epithelial cell density in the skin of live adult mice triggers changes in the immune cell density, but not vice versa. This suggests that the immune tissue composition in the epidermis is influenced by epithelial cells. Epidermal immune cell patterning is organized and actively maintained in a tiling pattern. When LCs (Langerhans cells) are ectopically removed, neighboring epidermal LCs move into the emptied spaces and re-establish the pattern. The GTPase Rac1 is required for LCs to maintain their dendritic morphology, limited mobility, and tiling pattern. Overall, Greco’s lab discovered that during epidermal homeostasis, the spatial distribution of immune cells is highly regulated, at least in part by the epithelial stem cells.
I found the Special Interest Symposium: Confronting Bias in Scientific Culture, especially useful. Not only did it address how to pursue innovation in developmental biology,but it also encouraged me to think critically about my own role in changing the field and making it more inclusive. Mary Alice Scott from New Mexico State University spoke about cultural bias in science and how there are implicit lessons embedded in learning culture that are often unintended. Scott Gilbert from Swarthmore College spoke about the importance of establishing a culture of inclusive diversity and the importance of micro-affirmations, such as smiles, “good jobs,” engagement, and recognition of people who are under-represented inscience. Both speakers raised issues I have been thinking about especially while taking the Amherst College course ‘Being Human in STEM’. This course discusses the obstacles faced by STEM students of color and low-income and engages us in conversations about imposter syndrome, how our identity impacts our journey in STEM, and how important it is to make STEM inclusive starting at a young age.
Postdoctoral scientists presented their ground-breaking work in the Hilde Mangold Postdoctoral Symposium. A talk that particularly caught my interest was given by Zak Swartz, a postdoctoral fellow from the Whitehead Institute for Biomedical Research, who talked about the role of dishevelled in oocyte development of the sea star Patiria miniata. When dishevelled was knocked down, cells failed to gastrulate and upregulate the expression of WNT target genes. Swartz concluded that a cue at the vegetal pole of the oocyte must recruit Disheveled, which appears to colocalize with granules on Lamp1 positive endosomes.
In the Organoids: A Window to Developmental Processes session, we heard about the insights of organoids into liver and endometrium development. Sarah Saxton from the University of Washington showed how engineered liver tissues can replace damaged organs or compensate for the loss of function, and found that hepatoblast organoids can survive ectopic implantation and can produce human proteins that are measurable in the blood serum. This suggests that the grafts can integrate within the host vasculature and have good potential for a stable cell source for bioengineering. Mirna Marinic from The University of Chicago showed that using postpartum tissue is advantageous for forming endometrium organoids: it is technically easier to obtain, ethically less questionable and there are known pregnancy outcomes. Overall, personalized organoids engineered from different cell types can be used to study a variety of conditions.
In the Developmental Biology and Global Health session, we heard about the sexually transmitted ZIKA virus and a gene that causes infertility. Jennifer Watts, a Ph.D. candidate from Michigan State University showed how the sexually transmitted ZIKA virus affects inner cell mass fate in the zona-free blastocyst, thus making 2-cell embryos most susceptible. Maria Mikedis, a postdoctoral fellow from Whitehead Institute for Biomedical Research talked about a gene that causes infertility in mice. The DAZL protein (a member of the DAZ proteins found in men and associated with spermatogenic failure when not expressed) affects genes that are critical for spermatogonial development as well as broad regulators of fundamental cellular processes, specifically transcription and splicing.
Two talks in the Seeing is Believing: Imaging Revolution session highlighted cochlear and notochord development. Elizabeth Driver from the Matthew Kelley National Institute on Deafness and Other Communication Disorders at the NIH spoke about how Myosin II plays a critical role in the developing mammalian cochlea. She concluded that the coupling of Myosin II and E-cadherin acts in a complementary manner to control the size of hair cells, thus supporting cells and the junctions between them in order to ensure proper patterning of the cochlear sensory epithelium. Marissa Gredler from the Sloan Kettering Institute presented her work on notochord development, describing how, in the first phase of convergent extension, cells move to the surface where they undergo a mesenchymal-to-epithelial transition, and then move to the second phase where they undergo convergent extension characterized by mediolateral intercalation, cell mixing, and lateral protrusive activity.
Among the interesting talks in the Endless Forms Most Beautiful: Role of Biodiversity in Developmental Biology session, Ahmet Karabulut, a predoctoral researcher from the Stowers Institute for Medical Research, presented work on the venomous harpoons of the sea anemone Nematostella vectensis,showing that the harpoons are formed by two substructures: a shaft and a tubule. Interestingly, the harpoon discharge occurs in three stages: capsule explosion, shaft eversion, and tubule movements into the prey. The elastic energy is released by the shaft eversion and is transferred to the tubule as kinetic energy.
The Award Lectures were truly inspiring. Brigid Hogan, from Duke University and recipient of the FASEB 2020 Excellence in Science Award, spoke about the obstacles she had to overcome as a woman joining the field of developmental biology in an under-developed department. Hogan went on to discuss her research where she made important discoveries in mouse development and concluded that Pax6 is a highly conserved regulator of eye development. Cagney Coomer, from The University of Kentucky and recipient of the Society for Developmental Biology SDB Trainee Science Communication Award, spoke about her humanitarian work and is the founder of “Nerd Squad.” The missions of “Nerd Squad” are to empower brown and black girls interested in STEM, to design and develop culturally relevant STEM curricula, and to engage schools and the community in hands-on STEM activities. Celina Juliano, from the University of California Davis and recipient of the SDB – Elizabeth D. Hay New Investigator Award, spoke about her work on Hydra, discussing how conserved injury response transcription factors directly activate WNT signaling. Jo Handelsman, from the Wisconsin Institute for Discovery and the recipient of the Viktor Hamburger Outstanding Educator Prize, spoke about her report to President Obama about the need for more STEM and STEM-literate college graduates. In trying to create more STEM inclusive classes for undergraduates, Handelsman helped create “Tiny Earth”. Its goal is to inspire students about the power of science, teach them about bacterial cells, aid the antibiotic resistance crisis by allowing students to participate in antibiotic discovery, and make it cheaper and more efficient for pharmaceutical companies. Ray Keller, from the University of Virginia and recipient of the Developmental Biology-SDB Lifetime Achievement Award, spoke about his path in developmental biology, his work on morphogenesis, especially in the biomechanics of convergent extension during gastrulation of Xenopus. Finally, Claude Desplan, from New York University and recipient of the Edwin G. Conklin Medal, spoke about his work on Drosophila neural cells.
In my opinion, the online SDB conference this year was great in being so accessible to undergraduate students, as we were able to go back and re-watch the recorded talks. I would recommend undergraduates to attend SDB in the future as long as presentations are recorded – it really helps to be able to re-watch them carefully in order to fully absorb the information. I found that some speakers used specialized language that made the material difficult to understand, yet others were easy to follow with clearly communicating slides and summary pages. I found some acronyms hard to follow, which made following the talks difficult: writing out the meaning of acronyms on the slide would be very helpful. All in all, it was a great experience to watch people present their research and share their passion for their work. Lastly, it was refreshing to also have presentations on important conversations we should be having on how to improve STEM, such as enhancing diversity and making science courses more accessible and inclusive.
I would like to thank the SDB and the meeting organizers for making undergraduate registration free of charge this year, and for providing access to the online recorded presentations. I would also like to thank the Node and Aidan Maartens for his comments on this write-up.