January 9 | Verónica Martínez-Cerdeño
Speaker: Verónica Martínez-Cerdeño, Associate Professor, Pathology and Laboratory Medicine
Location: Life Sciences Building, Room 1022 (see parking and transportation information below)
Time: Thursday, January 9, 3:10-4:00PM
Title: Cortical interlaminar astrocytes during development and evolution
Abstract: Astrocytes are one of the main cell types in the cerebral cortex of the brain. Cortical astrocytes are known as protoplasmic and occupy a spherical cortical area where they exert their action. However, another type of astrocyte, the interlaminar astrocyte (ILA), is also present in the cortex. ILA have a soma in layer I, long interlaminar processes running toward deep cortical layers, occupy columnar area, and exert actions across multiple cortical lamina.
ILA were discovered more than 100 years ago, but since then they have received little attention. It is believed that ILA are characteristic of the primate brain, however our studies have indicated that they are common to many mammalian species. We examined the cerebral cortex from 46 species encompassing most orders of therian mammals, including 22 primate species, and discovered that there are two distinct ILA types, that we named “pial ILA” and “subpial ILA”, with specific somatic morphology, position within layer I, and presence across species. We also found that ILA can be “rudimentary ILA” with short processes, or “typical ILA” with longer processes. We found that pial ILA are present in all mammals, while subpial ILA are absent in marsupials, and typical subpial ILA are only found in primates. We confirmed ILA astrocytic nature by investigating their molecular properties and found that while the density of pial ILA somata only varied slightly, the complexity of ILA processes varied greatly across species, reaching the highest values in primates, including human.
ILA were known to be present and develop postnatally, but when exactly they appear during development is not known. We analyzed specific prenatal and postnatal developmental stages of mouse, macaque, chimpanzee and human, and found an increasing ILA morphological complexity throughout development. We provided comprehensive data for primate ILA developmental progression and origin, and how it compares with rudimentary ILA in mouse. We found that ILA are generated prenatally, likely from a late radial glial cell cohort, locally proliferate before gestation ends, and grow interlaminar processes postnatally. Data obtained from this project will shed light on the ILA role in the evolution and development of the cerebral cortex. We will next unravel the molecular mechanisms responsible for the appearance of ILA in primate and specifically in the human cerebral cortex.
January 23 | Mariel Vazquez
Speaker: Mariel Vazquez, Professor of Mathematics and of Microbiology and Molecular Genetic
Location: Life Sciences Building, Room 1022
Time: Thursday, January 23, 3:10-4:00PM
Title: Reconnections: A Link Between Mathematics, Physics and DNA
Abstract: What do the deformations of a smoke ring have in common with the way DNA recombines? They are both examples of reconnection events, which are common in biology and in physics. We model reconnection using mathematical tools from the field of topology. We also use computer simulations and visualization. These methods yield a better understanding of the action of recombination enzymes on DNA and help explain the striking similarities between reconnection processes at many different scales. This talk will be accessible to students.
January 30 | Rose Kagawa
Speaker: Rose Kagawa, Assistant Professor, Emergency Medicine
Location: UC Davis Medical Center, Sacramento. Shriners Hospital, 7th floor conference room, please check in at front desk
Time: Thursday, January 30, 3:10-4:00PM
Title: Comprehensive Background Check Policies and Firearm Violence
Abstract: Firearm morbidity and mortality are major public health and safety concerns in the United States and effective policies for reducing firearm violence are urgently needed. Comprehensive Background Check policies seek to prevent high-risk individuals from obtaining firearms. However, their effectiveness has proven variable. This talk will review the literature on the effectiveness of comprehensive background check policies and discuss elements of these policies that may moderate the policies’ effects.
February 6 | Fernanda Ferreira
Speaker: Fernanda Ferreira, Professor, PsychologyDr. Fernanda Ferreira
Location: Life Sciences Building, Room 1022
Time: Thursday, February 6, 3:10-4:00PM
Title: Translating thoughts into words: Linearization decisions during speaking
Abstract: Speakers must decide how to convert unordered thoughts and ideas into a structured sequence of linguistic forms that communicates their intended message; that is, to speak, they must solve the linearization problem. One solution to the linearization problem is for speakers to begin with information that is easy to access and encode, allowing them to retrieve more difficult material during articulation and minimizing the need for pauses and other disfluencies. On this view, the syntactic form of a sentence emerges as a byproduct of speakers’ attempts to accommodate the early placement of a constituent. This incremental strategy is also thought to characterize multi-utterance production, which implies that the initial utterance of a discourse will reflect easily accessed or primed content. However, evidence for this kind of incremental planning strategy during multi-utterance production is sparse. Based on a new line of research using scene description tasks, we have developed a competing theory which assumes that speakers build a detailed macro-plan for the upcoming sequence of utterances. This work shows that speakers do not begin their descriptions with information that is salient or easy, but instead start with what is most meaningful. One key innovation of this work is our application of new techniques for quantifying the spatial distribution of meaning over a scene to the challenge of explaining linearization during language production. Our results suggest that a linearization plan guides speakers’ attention during language production and determines the sequencing of utterances, in contrast to “see-say” models of speaking which assume an incremental process. Moreover, application of the same approach to single-sentence production suggests that the language production system as a whole is less incremental than has been assumed.
February 13 | James Letts
Speaker: James Letts, Assistant Professor, Molecular and Cellular Biology
Location: Life Sciences Building, Room 1022
Time: Thursday, February 13, 3:10-4:00PM
Title: Towards an Atomic Understanding of Mitochondrial Respiration
Abstract: Aerobic cellular respiration, the process by which cells transfer electrons from sugars, fats and proteins to molecular oxygen (O2), generating water and carbon dioxide, is central to the energy metabolism of all eukaryotes and many prokaryotes. The final stages of aerobic respiration are carried out in the mitochondria, a double membrane organelle. The mitochondrial electron transport chain (ETC) complexes of the inner mitochondrial membrane (IMM) catalyze the terminal electron transfer reactions. These large membrane protein complexes couple the energetically downhill transfer of electrons (from NADH and succinate to O2) to the pumping of protons (H+) across the IMM. The large H+ electrochemical gradient thus generated is used by the adenosine triphosphate (ATP) synthase complex to synthesize ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi), maintaining a near-constant [ATP]/[ADP][Pi] disequilibrium, known as the phosphorylation potential, throughout the cell. By coupling cellular reactions to ATP hydrolysis, the energy stored by the phosphorylation potential is used to power nearly all cellular processes. Here I will discuss our work in elucidating the atomic-resolution structures of ETC complexes from diverse eukaryotes. Our ultimate goal is to generate a complete understanding of the molecular mechanisms enabling the activities of these complexes, which are fundamental for perpetuating eukaryotic life.
February 20 | Wilsaan M. Joiner
Speaker: Wilsaan M. Joiner, Assistant Professor, Neurobiology, Physiology and Behavior and Neurology
Location: Life Sciences Building, Room 1022
Time: Thursday, February 20, 3:10-4:00PM
Title: Using Novel Imaging Techniques to Study the Motor Control of Upper Limb Amputees
Abstract: Amputees often cite difficulty of use as a key contributing factor for abandoning their prosthesis, creating a pressing need for an improved control methodology. A major challenge in providing intuitive control signals for prosthetic devices is the limited understanding we have of the patients’ control over the remaining limb muscles. For example, (1) how many specific/separable activation patterns (i.e., degrees of freedom) of the residual muscles are available to control an external device, (2) to what extent can these activation patterns be finely modulated and (3) is this modulation intuitive and easy to adapt to different situations/contexts? To address these questions, our group uses sonomyography—a method in which muscle mechanical deformations are sensed using ultrasound imaging. This method can non-invasively resolve individual muscles, including those deep inside the tissue, and detect dynamic activity within different functional muscle compartments in real-time. Importantly, the alignment between muscle activation and proprioception, as well as the ability to distinguish small, but significant differences in activation patterns allows a tractable method to extensively examine the control of the remaining musculature. In this study we examined the control of residual limb muscles in upper-extremity amputees (4 traumatic and 1 congenital) and able-bodied subjects. In the task, dynamic ultrasound images measured contracting muscle deformations during actual motions of the limb. This signal was used to move a screen cursor to a series of targets, and then hold the cursor at that location within a quantization bound. Both traumatic and congenital amputee subjects with no prior experience of using a sonomyography-based interface were able to demonstrate fine graded control of an end-effector controlled by the muscle activation patterns in the remaining forearm. In addition, when visual feedback of the cursor was systematically removed subjects could retain an acquired activation level using only their sense of proprioception. Together, our results demonstrate the potential of using sonomyographic signals to answer fundamental questions centered on the motor control of individuals the with limb differences. In addition, this sonomyographic approach may provide more intuitive control signals for future prosthetic devices.
February 27 | Juliana Maria Leite Nobrega de Moura Bell
Speaker: Juliana Maria Leite Nobrega de Moura Bell, Assistant Professor, Food Science and Technology
Location: Life Sciences Building, Room 1022
Time: Thursday, February 27, 3:10-4:00PM
Title: Enzyme-assisted aqueous extraction: a sustainable approach to improve the functional and biological properties of plant-based proteins
Abstract: Adequately feeding an increasing world population has become a worldwide pressing issue. Providing adequate quantities of sustainable and nutritional protein sources will likely require the combination of animal and plant-based proteins. The increasing development of new food products and consumers' desire for a plant-based protein diet has spurred research efforts to extract dietary proteins from many plant-based sources as animal protein alternatives. The enzyme-assisted aqueous extraction process is an environmentally friendly strategy that enables the simultaneous extraction of oil and protein from many food materials without the use of flammable solvents. This green extraction technique allows for the fractionation of food materials into oil-, protein-, and fiber-rich fractions that can be further converted into food, animal feed, and fuel. Our research goal is to develop innovative extraction and recovery strategies to produce proteins with improved functionality (better solubility, emulsification, and foaming properties) and biological properties (higher digestibility, reduced allergenicity) for food and nutraceutical applications.
March 5 | Anna La Torre Vila
Speaker: Anna La Torre, Assistant Professor, Cell Biology and Human Anatomy
Location: Life Sciences Building, Room 1022
Time: Thursday, March 5, 3:10-4:00PM
Title: MicroRNAs in Retinal Development and Regeneration
Abstract: Several neurodegenerative diseases such as glaucoma cause a selective loss of retinal ganglion cells (RGCs), the neurons that form the optic nerve and connect the retina with the brain, leading to vision loss and ultimately blindness. Glaucoma affects millions of people worldwide and, unfortunately, these statistics are expected worsen in the next decade. All the treatments currently available only slow down the progression of the disease but, once the RGCs have degenerated, any therapeutic strategy to restore vision will require cell replacement by transplantation. Embryonic stem cells (ESCs) and induced-Pluripotent stem cells (iPSCs) hold the potential to become an unlimited source of donor cells but there are many critical features of this technology that need to be developed and further investigated before we can translate this approach to the clinic. For example, with all the current protocols, RGC production from stem cell cultures is very limited, making these technologies expensive and inefficient. Thus, before we can develop these therapies we need to understand how stem cells are able to generate the different cell types that form the nervous system. Our ongoing research has revealed that microRNAs are crucial regulators of the processes that differentiate neural stem cells into specific neuronal populations, including RGCs. By manipulating microRNA activities in stem cell cultures, we can overcome some of the current hurdles and hopefully, move these technologies one step closer to the clinic.
March 12 | Crystal D. Rogers
Speaker: Crystal D. Rogers, Assistant Professor, Anatomy, Physiology and Cell Biology
Location: Life Sciences Building, Room 1022
Time: Thursday, March 12, 3:10-4:00PM
Title: Evolution of transcription factors in the neural crest gene regulatory network
Abstract: Neural crest cells are embryonic stem-like cells that give rise to many derivatives including craniofacial bone and cartilage, teeth, inner ear structures, pigment cells, and most of the peripheral nervous system. Any failure in the specification, migration, or differentiation of these cells can lead to defects such as cleft palate, albinism, or peripheral nerve disorders. Understanding the complex mechanisms that control the development of these cells is crucial to identify causes for disorders and diseases caused by abnormal neural crest development. The neural crest gene regulatory network (GRN) is a hierarchical system of proteins that regulate how neural crest cells are created. Perturbation of any proteins in the GRN has the potential to create disorders in developing embryos. However, there is a critical lack of information about the specific functions of each protein in the GRN and we lack clarity of its level of conservation between species. This information is crucial to find markers of specific disorders and to identify relevant animal models of human disease. Here, we use protein expression and characterization studies to discover the hierarchical functional relationships between the proteins that regulate the formation and differentiation of neural crest cells. We performed analyses in three species; the chicken (Gallus gallus), quail (Coturnix japonica), and the axolotl (Ambystoma mexicanum) to identify differential and conserved protein functions between distantly related species. We have identified that the expression of important GRN proteins and that the embryonic response to perturbations of neural crest GRN factors differs between even closely related species. We hope to contribute a missing, fundamental element to our knowledge of the neural crest GRN, which in turn is crucial for the identification of appropriate research organisms to model human diseases.
