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Ribble Endowment 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.

Watch the seminar here!

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:
Location:
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.

Watch the seminar here!

Date:
Location:
THM 116

"Ribosomes in Gene Regulation: Controlling the Diversity of Proteins Made in Specific Cells, Tissues, and Organisms"

SelfieDr. Maria Barna | Barna Lab

BIO:

Dr. Barna obtained her B.A. in Anthropology from New York University and her Ph.D. from Cornell University, Weill Graduate School of Medicine. Dr. Barna was subsequently appointed as a UCSF Fellow through the Sandler Fellows program, which enables exceptionally promising young scientists to establish independent research programs immediately following graduate school. She is presently an Associate Professor in the Genetics Department at Stanford University. Dr. Barna has received a number of distinctions including being named a Pew Scholar, Alfred P. Sloan Research Fellow, and top ’40 under 40’ by the Cell Journal. She has received the Basil O’ Connor Scholar Research Award and the NIH Directors New Innovator Award. She is the recipient of the Elizabeth Hay Award, H.W. Mossman Award, Tsuneko and Reiji 'Okazaki Award', American Society for Cell Biology Emerging Leader Prize, the Rosalind Franklin Young Investigator Award, and the RNA Society Early Career Award. She is presently a NYSCF Robertson Stem Cell Investigator.

Abstract:

Work from our lab has changed the view that ribosomes are passive, indiscriminate machines. Our studies suggest that the translation machinery is a more dynamic, macromolecular complex with complex and specialized roles in the cell. A major interest in the lab is centered on understanding how ribosomes dictate when and where proteins are made to direct rapid and dynamic cell fate transitions. We study both the functional roles of ribosomes in normal mammalian development and in disease states such as ribosomopathies. We employ a wide-variety of technologies including mass spectrometry, sub cellular resolution imaging, as well as sequencing platforms to characterize ribosomes and their variation at the level of protein, rRNA, and modifications. Ultimately, the goals of the lab are to know how ribosomes function in sub cellular space, across different cell types, and the biological meaning of ribosome-mediated control of gene expression towards organismal development and evolution. Our recent research efforts are also centered on understanding how changes in the translatome influence tissue regeneration and regenerative potential across different kingdoms of life.

Check out the seminar here!

Date:
Location:
THM 116

"From the Pleistocene to the Anthropocene: Biodiversity in Changing Environments"

SelfieDr. Jessica Blois | Blois Lab

BIO:

Dr. Jessica Blois is an Associate Professor in the Department of Life and Environmental Sciences at UC Merced. Her research is particularly focused on examining the relative roles of environmental versus biotic drivers of biodiversity change, in merging data from different kinds of fossil proxies such as mammal bones and plant macrofossils, and in applying perspectives from the past to help conserve biodiversity. Her work combines field work aimed at broadening our samples of fossil and modern mammals, phylogeographic analyses to understand how genetic diversity is structured spatiotemporally, and paleobiogeographic modeling. Dr. Blois’ primary study system is North American mammals from the past 21,000 years, and she also has a strong focus on developing the paleo-informatic infrastructure to enable large-scale science.

Abstract:

Climates today are changing substantially and will continue to do so over the next hundred years and beyond. All of the different elements that comprise Earth’s biosphere—its biodiversity—depend on and respond to Earth’s climate in a variety of ways, and in turn, Earth’s biodiversity modulates the magnitude and trajectory of climate change. Species responses to highly novel climatic (and other anthropogenically-forced) conditions—which may fall outside the range of conditions experienced by species over their histories—will impact the adaptive capacity and evolutionary potential of species and shape future patterns of biodiversity. In this talk, I will present several recent projects illustrating how climate impacts biodiversity. I will focus on ecological processes that structure local populations and communities, and then move towards how we can scale up towards a broader understanding of how ecological processes structure biodiversity patterns across space and time.

Watch the seminar here!

Date:
Location:
THM 116

"Human Origins and Dispersals: Fossil and Genomic Perspectives"

SelfieHugo Reyes-Centeno HEVA (Human Evolution & Virtual Anthropology Lab) EduceLab

Dr. Hugo Reyes-Centeno is an evolutionary anthropologist specializing on the emergence of modern human anatomy and behavior over the last million years. In addition, he conducts inter-disciplinary research on human biocultural diversity and the study of natural and cultural heritage worldwide. Prior to joining the University of Kentucky in 2020 as Assistant Professor of Anthropology, he served as Scientific Coordinator and co-founder of the Center for Advanced Studies “Words, Bones, Genes, Tools” at the University of Tübingen (Germany), where he also completed a dissertation in the Institute of Archaeological Science and the Senckenberg Centre for Human Evolution and Paleoenvironments. His research has appeared in Cell, PNAS, Journal of Human Evolution, and PLoS Genetics, among other venues. He has performed paleontological and archaeological fieldwork in France, Italy, Peru, the Philippines, and Spain. Currently, he serves as Co-PI of the NSF-funded EduceLab: Infrastructure for Next Generation Heritage Science.

Abstract: Despite consensus on the emergence of anatomically modern humans in Africa and their subsequent dispersal into the rest of the world, the mode and timing of these processes remain controversial topics. In addressing them, data on human anatomical and genomic variation have sometimes generated conflicting inferences. Therefore, approaches that consider both lines of evidence under a common theoretical framework are important for reconciling competing evolutionary models. In this talk, I highlight research that tests competing models of human dispersal out of Africa, which applies quantitative genetic and population genetic methods to anatomical and genomic data. I discuss the caveats of these conclusions, including the influence of admixture between modern humans and other hominins. Furthermore, I examine how these findings align with the known human fossil record and a growing inventory of ancient genomes from archaeological and paleontological contexts. Finally, I review how ongoing field and laboratory projects in Eastern Africa, Southeast Asia, and South America shed light on human evolution, adaptations, and dispersals.

Group Map
Date:
Location:
THM 116

"Engaging in Science Policy"

 Erin Heath

Erin Heath is the Director of Federal Relations at the American Association for the Advancement of Science, the world’s largest general scientific society and publisher of the journal Science. The Office of Government Relations provides timely, objective information on science and technology issues to lawmakers, and it assists scientists in understanding and getting involved in the policy process.

Erin leads the federal policy team at AAAS and is heavily involved in efforts to empower scientists and engineers to engage with policymakers, the media and the public. She co-chairs the Coalition for National Science Funding, the Engaging Scientists and Engineers in Policy Coalition, and the steering committee of the Golden Goose Award. She played a key role in the launch of the Center for Scientific Evidence in Public Issues (EPI Center) at AAAS and serves on its internal advisory committee. She is also the inaugural chair of the Governing Board of the Journal of Science Policy and Governance.

Before joining AAAS, Erin worked for the American Institute of Biological Sciences, where she led the organization’s media training and outreach efforts and cut her teeth on science policy. Erin holds a Master of Science with Merit in Public Policy and Administration from the London School of Economics and Political Science. While in London, she served as a research assistant in Parliament. Prior to graduate school, she spent years as a journalist in Washington, most notably as a science policy reporter and columnist for the National Journal. She earned a B.A. in Journalism from the University of Maryland.

In 2017, Erin was awarded the AAAS Champion Award, given to an individual who has "championed" the mission of AAAS with a positive attitude and has inspired and motivated others to embrace and fulfill the AAAS vision.

 

Date:
Location:
THM 116
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