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Department of Biology Seminar

"Mechanisms of Development and Regeneration in Hydra"

Juliano SelfieDr. Celina Juliano | Juliano Lab

Bio:
Dr. Juliano joined the faculty at UC Davis in 2015 as an Assistant Professor in the Molecular and Cellular Biology Department and was promoted to Associate Professor with tenure in 2021. She is a developmental biologist with a long-standing interest in stem cell biology. Her doctoral research, mentored by Dr. Gary Wessel at Brown University, focused on understanding the molecular mechanisms underlying the maintenance of plasticity during sea urchin development. Dr. Juliano completed her post-doctoral work at Yale University in the laboratory of Dr. Haifan Lin with co-mentoring from Dr. Rob Steele at UC Irvine. At Yale, Dr. Juliano began working with Hydra, a small freshwater cnidarian that continually renews all cell types as an adult and has remarkable regenerative abilities. During her post-doctoral work, she discovered a critical role for the PIWI-piRNA pathway in Hydra stem cells. In her own laboratory at UC Davis, Dr. Juliano continues to use Hydra as a model to understand, stem cell function, development, and regeneration, with funding from the National Institutes of Health. Dr. Juliano was a recipient of the Elizabeth D. Hay New Investigator award from the Society for Developmental Biology in 2020 and she was named a UC Davis Chancellor’s fellow in 2024. Dr. Juliano is the founder of the biennial Cnidarian Model Systems Meetings, the founder and director of the annual Hydra Workshop (Marine Biological Laboratory), and a founding board member of the International Society for Regenerative Biology. 

Abstract:
In our laboratory at UC Davis, we use Hydra as a model to understand, stem cell function, development, and regeneration. As a starting point, we subjected the adult Hydra to single cell sequencing, created a molecular map of the entire organism, and built differentiation trajectories to describe each stem cell differentiation pathway. This work now serves as a foundation for our research goals, which include dissecting the molecular mechanisms underlying stem cell differentiation, understanding how the conserved injury program triggers developmental pathways during regeneration, and understanding how the Hydra nervous system is able to continually remove and add neurons into neural circuits.

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Date:
Location:
THM 116

"The Missing Pieces: Lost Ecological Function following the Terminal Pleistocene Megafaunal Extinction"

Smith SelfieDr. Felisa Smith | Smith Lab

Bio:
Felisa Smith is a Distinguished Professor in the department of Biology. A conservation paleoecologist, she integrates modern, historic and fossil mammal records to investigate pressing environmental issues such as climate change and biodiversity loss. Over her career she has worked on organisms from microbes to mammoth, but vastly prefers the latter. Most recently Smith has been using the terminal Pleistocene megafauna extinction as a proxy for understanding modern mammal biodiversity loss. In addition to her 3 books, she has written~120 papers/book chapters in a wide variety of scientific journals, and taught scientific blogging at UNM (http://unm-bioblog.blogspot.com). She has participated in many audio and video programs including National Public Radio, BBC World Service, BBC Earth, and BBC’s Horizon series, German public radio, the Canadian Broadcasting Corporation, and the History Channel as well as numerous print interviews/essays. Felisa was elected a Fellow of the Paleontological Society in 2020, was awarded the Merriam Award from the American Society of Mammalogists in 2022, and is the 68th recipient of the UM Annual Research Lecturership in 2023. She is currently the President of the American Society of Mammalogists and Past President of the International Biogeography Society.

Abstract:
The conservation status of large-bodied mammals is dire. Their decline has serious consequences because they have unique ecological roles not replicated by smaller-bodied animals. Here, we use the fossil record of the megafauna extinction at the terminal Pleistocene to explore the consequences of past biodiversity loss. We characterize the isotopic and body-size niche of a mammal community in Texas before and after the event to assess the influence on the ecology and ecological interactions of surviving species (>1kg). Pre-extinction, a variety of C4-grazers, C3-browsers, and mixed-feeders existed, similar to modern African savannas, with likely specialization among the two sabertooth cats for juvenile grazers. Post-extinction, body size and isotopic niche space were lost, and the δ13C and δ15N values of some survivors shifted. We see mesocarnivore release within the Felidae: the jaguar, now an apex carnivore, moved into the specialized isotopic niche previously occupied by extinct cats. Puma, previously absent, became common and lynx shifted towards consuming more C4-based resources. Lagomorphs were the only herbivores to shift towards Cresources. Body size changes from the Pleistocene to Holocene were species-specific, with some animals (deer, hare) becoming significantly larger, and others smaller (bison, rabbits) or exhibiting no change to climate shifts or biodiversity loss. Overall, the Holocene body size-isotopic niche was drastically reduced and considerable ecological complexity lost. We conclude biodiversity loss led to reorganization of survivors and many ‘missing pieces’ within our community; without intervention, the loss of Earth’s remaining ecosystems that support megafauna will likely suffer the same fate.

Texas Memorial Museum

Dr. Smith at Texas Memorial Museum

Fossils

Fossils under study

Cave art

Cave art showing human hunting

Date:
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THM 116

"Prebiotic Chemistry and the Origin of Life: the 1953 Miller experiment"

Dr. Antonio Lazcano Araujo 

Bio:
Antonio Lazcano is Distinguished Professor at the Universidad Nacional Autónoma de México, where he works on the origin and early evolution of life. He has worked in prebiotic chemistry, analyses of meteorites and, more lately, on bioinformatics and the reconstruction of early stages of celular evolution. He is author or coauthor of about 200 research papers and chapters in books. He has written several boioks for the general public, including El Origen de la Vida, La Chispa de la Vida y La Bacteria Prodigiosa. He has been Visiting Professor or Scholar in Residence at the Univeristy of Habana, Autónoma de Madrid, Houston, Valencia, Orsay Paris-Sud, University of California, San Diego, Universita di Roma La Sapienza, Institut Pasteur, ETH Zentrum in Zurich and the A. N. Bakh Institute of Biochemistry of the USSR. For ten years he was part of the NASA Astrobiology Institute Oversee Committee, and President of the Gordon Research Conference of the Origins of Life, and twice President of the International Society for the Study of the Origins of Life, being so far the only Latin American scientist to hold this position. He has received three Honoris causa, one from the Universita di Milano (Italy, 2008), one from the Universidad de Valencia (Spain, 2014), and a third one in 2015 from the  Universidad de Michoacan (Mexico). In 2013 the Third World Summit of Evolution granted him the Charles Darwin Distinguished Scientist Award, and in 2018 the College de France granted him the Guillaume Bude Medal. In October 2014 he was elected to the Colegio Nacional, the most Mexican important academic and cultural institution.

Abstract:
Led by Oparin’s hypothesis on a heterotrophic origin of life, in the early 1950s Stanley L. Miller began his PhD thesis under the supervision of Harold C. Urey, attempting to simulate the conditions of the primitive Earth. To do this, Miller placed a mixture of methane, ammonia, and hydrogen in a flask, to which water vapor from another flask simulating the primitive seas of the planet was added. After subjecting the mixture of gases to the action of electrical discharges, Miller found that in a very short time amino acids, urea, and other compounds of biochemical importance had been formed. The experiment was considered a demonstration of the premises of Oparin's theory, and marks the origin of the experimental study of the appearance of life. Analyses of the original samples from Miller's experiment using contemporary techniques has shown that the variety of compounds formed abiotically is much greater than originally reported, allowing a more complete picture of the processes that led to the origin of the first organisms.

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Date:
Location:
THM 116

"Life by a Thousand Cuts: Archaea as a Model for Evo-Devo Mechanosensing"

Bisson Selfie

Dr. Alex Bisson | Bisson Lab

Abstract:
Cells sense and respond to their physical surroundings, using organized molecular machinery
to convert mechanical environmental signals into biochemical information. Maybe more importantly, little is known about how cells' material properties co-evolve with their
environment. Using genetics, biophysics, and advanced microscopy tools, the Bisson Lab aims to understand archaeal cells' self-organization and behavior in response to physical cues. Here,
I will discuss our recent discovery of how specific mechanical confinement triggers the development from a unicellular to a tissue-like lifestyle similar to known primitive multicellular eukaryotes. This observation not only gives a new perspective over the emergence of complex multicellularity, but gives us the opportunity to compare the behavior and the genome of hundreds of cultivable archaeal species.

Bisson Graphic

Date:
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THM 116

"The Role of Oxytocin Signaling Pathways in the Neuroimmune Response to Mate Bond Dissolution"

Glasper Selfie

Dr. Erica Glasper

Bio:
Erica R. Glasper graduated with honors from Randolph-Macon College in Ashland, Virginia, in 2002 with a major in Psychology and a minor in Biology. Initially pre-med, Erica discovered neuroscience during her freshman year at Randolph-Macon and was selected three times as a Summer Undergraduate Research Fellow. Her research experiences, aided by keen faculty mentorship, set her professional journey in motion. Erica went on to earn an M.A. and Ph.D. in Psychobiology and Behavioral Neuroscience from The Ohio State University. During her time as a postdoctoral scholar at Princeton University, she was supported by a fellowship from the UNCF/Merck Science Initiative and the National Institute on Aging at the National Institutes of Health. In 2011, Dr. Glasper joined the faculty at the University of Maryland – College Park, in the Department of Psychology, as an Assistant Professor. Her research in behavioral neuroendocrinology takes a multidisciplinary approach to understanding how experiences can shape our brains and resulting behavior. Following success as a researcher and educator, she was awarded tenure and promoted to the rank of Associate Professor. During the summer of 2021, the Glasper Lab returned to The Ohio State University, where she joined the Department of Neuroscience and the Institute for Behavioral Medicine Research within the College of Medicine as a tenured Associate Professor. She is excited about continued research success, and her return to the Buckeye State, using a combination of behavioral paradigms along with neuroendocrine, neuroanatomical, neuroimmune, neurochemical, and pharmacological techniques in three lines of research: 1) neurobiology of parenting, 2) neuroprotective role of rewarding social experiences, and 3) enduring consequences of paternal deprivation. Her research is currently funded by the NIH and The Ohio State University Wexner Medical Center.

Abstract:
Loss of a mate results in diverse impairments in bodily and psychological health. In this study, we tested the hypothesis that disrupting a mate bond, in the monogamous California mouse (Peromyscus californicus), would increase the neuroimmune response to a peripheral inflammatory stimulus (lipopolysaccharide [LPS]) through alterations in the oxytocin system. Adult (6-8 months old) male and female mice were exposed to three experimental conditions: 1) single housed, 2) mate bonded, or 3) mate-bonded separation. Mice were either injected with a vehicle (VEH) or an intraperitoneal injection of LPS (1mg/kg) and sacrificed 4-6 hours later.  While mate bond disruption did not increase anxiety-like behavior during open-field testing, physiological indices of mate bond disruption were observed. Males lost significantly more body weight following mate-bond separation, compared to the mate-bonded groups – this effect was not observed in females. Pro-inflammatory cytokine concentration (TNF and IL-1 beta) mRNA levels, measured by RT-qPCR in the hippocampus (HIPP) and hypothalamus (HYPO), were significantly enhanced in LPS-treated female mice following mate bond disruption, compared to the mate-bonded group. Mate bond dissolution did not exacerbate the LPS-induced increase in pro-inflammatory cytokines in males. Disruptions in oxytocin (OXT) signaling may contribute to the increased pro-inflammatory response in LPS-injected mice following mate bond dissolution, as HIPP mRNA levels for the oxytocin receptor (OXTR) in separated males and females were significantly decreased. Independent of endotoxic challenge, TNF and OXTR mRNA levels in separated mice were negatively correlated (as OXTR expression went down, TNF expression went up). Together, these results suggest that the effects of mate bond disruption in neuroimmune responsivity may involve alterations to OXT signaling. 

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Date:
Location:
THM 116

"The Problem of Time in Climate Change Ecology"

Wolkovich Selfie

Dr. Elizabeth Wolkovich | Wolkovich Lab

Bio
Elizabeth Wolkovich is an Associate Professor in Forest and
Conservation Sciences and Canada Research Chair at the University of British Columbia. She runs the Temporal Ecology Lab, which focuses on understanding how climate change shapes plants and plant communities, with a focus on shifts in the timing of seasonal development (e.g., budburst, flowering and fruit maturity)---known as phenology. Her lab both collects new data on forest trees and winegrapes and collates existing data to provide global estimates of shifts in phenology with warming from plants to birds and other animals, and to understand how human choices will impact future winegrowing regions. Her research benefits from an interdisciplinary team of collaborators from agriculture, biodiversity science, climatology, evolution and viticulture, as well as from shared long-term datasets from across North America and Europe.

Abstract
Forty years ago ecology became increasingly focused on spatial structure and pattern, as researchers realized how fundamentally habitat loss and fragmentation reshapes populations and communities. A generation later, with spatial ecology firmly established as a cross-disciplinary, multi-scale field, anthropogenic climate change has forced ecology to revisit the importance of time. As warming stretches growing seasons around the globe, populations, species, communities and ecosystems are responding in turn. In this talk I outline two major challenges of temporal ecology with anthropogenic warming: stretched time and accelerated time. Focusing on
plant phenology I show how longer growing seasons may re-assemble communities: first I focus on examples from invasion biology then I build to a more general theory. Next I show how how warming may make many biological processes that are dependent on thresholds appear to slow as warming continues. This is because warming accelerates biological time while calendar time stands still. I close by reviewing preliminary results that merge phenological cues with trait ecology to show that forests may assemble via their spring phenology.

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Date:
Location:
THM 116

"The Molecular Circadian Clock and the Impact of Disrupted Rhythms and Sleep on Health and Disease"

Turek Selfie

Dr. Fred Turek

Bio:
Fred W. Turek, PhD received his undergraduate degree in the biological sciences from Michigan State University in 1969, and his PhD from Stanford University in 1973 where he carried out research on circadian and seasonal rhythms.  After postdoctoral training at the University of Texas at Austin, he took a faculty position at Northwestern University where he served as the Chair of the Department of Neurobiology & Physiology from 1987-98.  Dr. Turek is the founder and current Director of the Center for Sleep and Circadian Biology at Northwestern University.  Dr. Turek was the founding president of the Society for Research on Biological Rhythms (SRBR) and served in this capacity for six years.

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Date:
Location:
THM 116

"Genetic, Social, and Developmental Drivers of Within-population Behavioral Variation"

Laskowski Selfie

Dr. Kate Laskowski | Laskowski Lab

Bio:
Dr. Kate Laskowski is interested in investigating how evolution has shaped the developmental processes that generate behavioral individuality. She does this by generating replicate individuals and groups of the naturally clonal fish, the Amazon molly, allowing her to “replay the developmental clock.” Kate obtained her Bachelor’s of Science at the University of Maryland Baltimore County and her PhD from the University of Illinois where she worked under Alison Bell. She then moved to Berlin Germany to work at the Leibniz Institute of Freshwater Ecology & Inland Fisheries with Max Wolf and Jens Krause before joining the Department of Evolution & Ecology at the University of California Davis in 2019.  

Abstract:
Individual behavioral variation is ubiquitous across the animal kingdom. Explaining the continued generation and maintenance of such variation is a fundamental goal in behavioral and evolutionary ecology. Our research tests key predictions drawn from theoretical models about how genetic correlations and developmental processes can drive the emergence of consistent individual behavioral variation. This work has shown that competition for, and acquisition of, resources may play key roles in shaping behavior variation both on evolutionary and developmental timescales. Using the clonal Amazon molly and an innovative high-resolution tracking system we can follow and manipulate individual experience with salient environmental cues such as resource availability and relative risk. We can track the behavioral development of individual fish from birth in, up to now, unprecedented detail, allowing us to pinpoint exactly when and in response to which cues individuality emerges. Our results highlight that in order to fully explain the presence of individual behavioral variation we need a comprehensive conceptual framework that explicitly accounts for how natural selection has shaped the developmental process.
 

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Laskowski Fish

Date:
Location:
THM 116

"Quantitative Proteomics for Understanding Epigenetic Mechanisms in Human Disease"

Garcia Selfie

Dr. Benjamin Garcia | Garcia Lab

Bio: 
Benjamin A. Garcia obtained his BS in Chemistry at UC Davis in 2000, where he worked as an undergraduate researcher in Prof. Carlito Lebrilla’s laboratory. He received his PhD in Chemistry in 2005 at the University of Virginia under Prof. Donald Hunt and then was an NIH NRSA Postdoctoral Fellow at the University of Illinois under Prof. Neil Kelleher from 2005-2008. From there Ben was appointed as an Assistant Professor in the Molecular Biology Department at Princeton University from 2008-2012, until his recruitment as the Presidential Associate Professor of Biochemistry and Biophysics at the University of Pennsylvania Perelman School of Medicine in 2012, promoted to full Professor in 2016, and named the John McCrea Dickson M.D. Presidential Professor in 2017. Ben moved in the summer of 2021 to the Washington University School of Medicine in St. Louis to become the Raymond H. Wittcoff Distinguished Professor and Head of the Department of Biochemistry and Molecular Biophysics. The Garcia lab has been developing and applying novel proteomic approaches and bioinformatics for interrogating protein modifications, especially those involved in epigenetic mechanisms such as histones during human disease, publishing over 400 publications. He is presently an Associate Editor of the Analytical Chemistry, and Mass Spectrometry Reviews journals; and serves on the editorial boards for the Molecular Omics, the Journal of Proteome Research and the Molecular and Cellular Proteomics journals. He also serves on the Board of Directors for the U.S. Human Proteome Organization (HUPO), the HUPO Governing Council/Executive Committee and the Executive Committee of the American Chemical Society (ACS) Analytical Chemistry Division. Ben has been recognized with many honors and awards for his mass spectrometry research including the American Society for Mass Spectrometry (ASMS) Research Award, a National Science Foundation CAREER award, an NIH Director’s New Innovator Award, the Presidential Early Career Award for Scientists and Engineers (PECASE), an Alfred P. Sloan Fellowship, the PITTCON Achievement Award, the Ken Standing Award, the ACS Arthur F. Findeis Award, The Protein Society Young Investigator Award, the ASMS Biemann Medal, the HUPO Discovery in Proteomic Sciences Award, the Eastern Analytical Symposium (EAS) Outstanding Achievement in Mass Spectrometry Award and was named a Fellow of the Royal Society of Chemistry.

Abstract:
Histones are small proteins that package DNA into chromosomes, and a large number of studies have showed that several post-translational modification (PTM) sites on the histones are associated with both gene activation and silencing.  Along with DNA and small non-coding RNA, histone PTMs make up epigenetic mechanisms that control gene expression patterns outside of DNA sequence mutations. Dysregulation of these chromatin networks underlie several human diseases such as cancer. Here I will give an update on technology advancements that have allowed for high-throughput quantitative mass spectrometry analyses of histone PTMs and chromatin structure, and how we are applying these methods to understand epigenetic reprogramming found in malignant peripheral nerve sheath tumors (MPNSTs). MPNST is an aggressive sarcoma with recurrent loss of function alterations in polycomb-repressive complex 2 (PRC2), a histone-modifying complex involved in transcriptional silencing.

Date:
Location:
THM 116

"Be Fruitful and Multiply: How Reproductive Capacity Evolves"

Selfie

Dr. Cassandra Extavour | Extavour Lab

Bio
Cassandra Extavour is a native of Toronto, where she attended the University of Toronto Schools and went on to obtain an Honors BSc at the University of Toronto with a specialist in Molecular Genetics and Molecular Biology, a Major in Mathematics and a Minor in Spanish. She obtained her PhD with Antonio Garcia Bellido at the Severo Ochoa Center for Molecular Biology at the Autonomous University of Madrid. She performed postdoctoral work first with Michalis Averof at the Institute for Molecular Biology and Biotechnology in Crete, Greece, and subsequently with Michael Akam at the University of Cambridge. At Cambridge she received a BBSRC Research Grant and became a Research Associate in the Department of Zoology. In 2007 she established her independent laboratory as an Assistant Professor in the Department of Organismic and Evolutionary Biology at Harvard University, where she was promoted to Associate Professor in 2011 and to Full Professor in 2014. In 2021 she became a Howard Hughes Medical Institute Investigator, and was named the Timken Professor of Organismic and Evolutionary Biology and of Molecular and Cellular Biology at Harvard. Click here to read more.

Abstract:
Reproduction is a crucial fitness parameter, essential for species survival and evolution. Despite its importance, there is massive variation in reproductive capacity across animals, even between very closely related species. Moreover, reproductive capacity can be modified by environmental and ecological factors. Our aim is to understand how genetic variation interacts with ecological variation to regulate distinct and reproductive capacities between species, to determine whether and how ecological variation contributes to the evolution of adaptive variation in reproductive capacity. Our approach takes advantage of the fact that in sexually reproducing animals, the number of offspring that an individual can produce is often predicted by the anatomy of the ovary or testis, the sites of gamete production. In female insects, ovaries are subdivided into egg-producing units called ovarioles, which are generated in species-specific numbers during development. Ovariole number, and correspondingly reproductive capacity, can vary by more than four orders of magnitude across insects. I will discuss our findings on the mechanisms of genetic and environmental control of ovariole number in closely and distantly related insect species, and their implications for the broader questions of the genetic and developmental basis of fitness-relevant evolutionary change.

Date:
Location:
THM 116
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