Saint Mary’s Students Shine at Biology Conference

Zlatas Serebnitskiy, Biology ’21 Saint Mary’s students from the Biology/Biochemistry Department had the experience of a lifetime, with one bringing home top honors after presenting independent research at the 44th Annual West Coast Biological Sciences Undergraduate Research Conference (WCBSURC). At the conference, held at the University of San Diego on April 6, students Emry Cohenour, Biochemistry ’19, Alexandria (Lexi) Luong, Biology ’19, and Zlatas Serebnitskiy, Biology ’21, presented their research before a sizeable gathering of scientists, academicians, and undergraduate students from other colleges and universities from across the nation. The annual conference is unique in that it is specifically designed for undergraduates and provides them with a forum to present original data they have generated in biology and related scientific fields. The conference also allows students to establish intercollegiate interactions among other students and faculty, and to learn about other research topics that their peers are undertaking.

Under the guidance of Associate Professor Sonya Schuh and Assistant Professor James Berleman, the students gave talks in the categories of development, anatomy/physiology, and microbiology ecology/evolution. “Doing hands-on research with our students and mentoring them in not only how to do science but how to communicate that science effectively and engagingly is so important and allows our students to become even better, more successful scientists, doctors, teachers, and professionals,” stated Schuh.

More than 200 abstracts were submitted by students across a broad range of disciplines—sharing their research in both poster and oral presentations. Serebnitskiy earned the coveted award for Best Oral Presentation in Microbiology. His presentation was titled “Microevolutionary Development of Myxococcus Xanthus: An Investigation of Predatory Processes.” “I was so honored to be awarded best presentation in microbiology. It was incredible to see diverse research from people all over the United States, and the most incredible part is that we were all undergrads,” stated Serebnitskiy.

Cohenour presented her research on theToxic Effects of BPA, BPAF, and Estradiol on Early Embryo Development and Survival.” “I gave a talk in front of an audience and a panel of judges, which has allowed me to become more comfortable with speaking and has provided me with skills on how to construct a well-developed talk, and gain a deeper appreciation for science,” shared Cohenour. “I also enjoyed being able to see the diverse topics explored by many young scientists at my age and learning about their research.”

Luong shared her research, titled “Targeting Closely Related Strains of Rhodospirillum Centenum in Response to Predatory Threat.” Luong was glad to participate in a conference that provided an opportunity for students from all cultural and economic backgrounds to showcase their scientific research. Serebnitskiy felt likewise, adding, “I hope other universities, public and private alike, allow more students of all backgrounds to pursue research. In the end, brilliance does not discriminate, especially not in age or gender.”

Schuh was thrilled that Saint Mary’s students had the opportunity to present their research, citing that when she was an undergraduate, opportunities like this were not available. She also expressed that the best scientists are brilliant communicators, and having opportunities early on for students to hone their skills and master the art of presenting will help them immensely as they become future leaders in science and as teachers and mentors. “Presenting their research at conferences, especially when they’ve had the opportunity to learn and work closely with their faculty mentor, is such a rare and important thing that our undergraduate students get to do here at Saint Mary’s,” stated Schuh. “I love watching my research students, many of whom are from marginalized backgrounds, evolve from inexperienced, sometimes shy students, to confident, poised, knowledgeable, charismatic speakers! It’s truly one of the most rewarding parts of my work.”

Last year, Saint Mary’s hosted the WCBSURC, which provided an opportunity for the College— and especially the Biology/Biochemistry Department—to achieve heightened recognition for faculty and student excellence. Next year, the conference will be held at Loyola Marymount University.

Student Presentation Abstracts

Emry Cohenour, Biochemistry ’19: “The Toxic Effects of BPA, BPAF, and Estradiol on Early Embryo Development and Survival.”

Bisphenol A (BPA) is a plasticizer used in the production of plastics. It is an endocrine-disrupter affecting reproductive and developmental processes across species. Next-generation BPA analogs such as bisphenol AF (BPAF) are now being used in “BPA-free” products. We analyzed the dose-dependent effects of BPA, BPAF, and 17b-estradiol on Xenopus laevis development and survival. Embryos were exposed to various concentrations of the chemicals or control media for 96 hours. We found BPA and BPAF caused severely disrupted cleavage divisions within the first 1–6 hrs of development. Most BPAF-treated embryos did not survive past 24 hours, with only 0–1% survival at 96 hours. Environmentally relevant doses of BPAF resulted in flexures of the spinal cord, shorter body axis, gut defects, craniofacial malformations, and severe mortality (LC50 = 0.013 mM). BPA induced similar defects, but was less potent and toxic (LC50 = 10.7 mM). Estradiol caused less severe, characteristic defects. Notably, BPAF was 1,000-times more toxic and potent than BPA. These findings underscore the greater toxicity of the replacement chemical BPAF, show that BPA and BPAF act through some but not all estrogenic pathways, and highlight the negative implications these plasticizers may have on human development.

Alexandria (Lexi) Luong, Biology ’19: “Targeting Closely Related Strains of Rhodospirillum Centenum in Response to Predatory Threat.”

Targeted single gene mutations are valuable research tools, as they reveal the specific impact of a single gene in a process. It is also possible to see the impact of single gene mutants on communities, revealing phenomena such as intercellular communication that signals a warning to the community. Myxococcus xanthus and Rhodospirillum centenum are model bacterial organisms for cell development research. M. xanthus is a predator that can eliminate species such as E. coli, but some R. centenum cells encyst in response to predation while vegetative cells are lysed. During this process, guanylyl cyclase is activated and R. centenum secretes cGMP to surrounding cells. Guanylyl cyclase mutants are rescued by mixing with exogenous cGMP or cGMP+ strains. This research uses qPCR and predation techniques to observe the impact of intercellular cGMP communication between microbial strains.

Zlatas Serebnitskiy, Biology ’21: “Microevolutionary Development of Myxococcus Xanthus: An Investigation of Predatory Processes.”

Myxococcus xanthus is a predatory member of the soil microfauna able to lyse fungi, achaea, and both Grampositive and Gram-negative bacteria. During predation, M. xanthus deploys anti-microbial secondary metabolites and changes cell behavior to form rippling wave structures for effective predation. With the current threat of antibiotic-resistant bacteria, research into antibiotic resistance and susceptibility is needed in order to benefit better health outcomes. Through the propagation of distinct M. xanthus lineages within lab-controlled predatorprey environments, lab evolution was observed for the impact on efficiency of predation. Over 2,000 generations have passed so far, with dramatic changes in predatory ability as well changes to other phenotypes and behaviors. Further examination of M. xanthus optimal predation under certain stressed settings was also done to further improve predation assays. Genomic analyses of evolved strains are projected for later this year.