Tag: Poster 50

Investigation of Supportive Cues in Early Stages of Pediatric Brain Cancer

Presenter: Kelsey Wahl

Mentor: Hui Zong

PM Poster Presentation

Poster 50

Medulloblastoma is the most common type of malignant brain tumor in children. During cerebellar development, granule neuron precursor cells (GNPs) proliferate along the external germinal layer in response to the sonic hedgehog signaling pathway. Mutations in the sonic hedgehog signaling receptor patched (Ptc) lead to tumors in the cerebellum through over-proliferation of GNPs. Over 50% of mice with the mutation develop foci of ectopic cells on the surface of the cerebellum between 3-6 weeks. Observations suggest that the ectopic cells may represent a pre-neoplastic stage of medulloblastoma. Although GNPs are unipotent progenitors that only give rise to granule neurons, lineage tracing studies in our lab have indicated that tumorigenic GNPs can also differentiate into glial cells. To further understand this fate switch and determine if it occurs prior to tumor formation, we looked for glia presence in Ptc pre-neoplastic lesions (PNLs). The appearance of glia cells in the earliest stages of tumor formation could provide insight into their potential supporting role in the tumor and in tumor cell transformation.

Normal as Found: Opportunities and Challenges in Developing a Necropsy Protocol for Evolutionary Veterinary Medicine

Presenter: Carly Pate

Co-Presenters: Andrea Eller and Ulirike Streicher

Mentors: Frances White and Lawrence Ulibarri, Anthropology

Poster: 50

Major: Anthropology and General Science

Evolutionary veterinary medicine is a burgeoning field, applying evolutionary perspectives to comparative and veterinary data. Because evolutionary research focuses on natural variation across species, veterinary medicine is
an obvious partner for understanding nonhuman anatomy. To meet this goal, cross-disciplinary work is required, but we need to be able to compare and exchange data. Utilizing the comparative collections in the University of Oregon Primate Osteology Lab, and in collaboration with both an evolutionary biologist and a wildlife veterinarian, we present a protocol that is designed for many vertebrate species and includes procedures for collecting normal and pathological variation. Published necropsies are surprising rare. Veterinary necropsies tend to be pathology- based, whereas anthropologists’ are focused on normal variation within and between species. The protocols cited and described in veterinary medicine tend to be particular to a single species and do not document repeatable procedures. Anthropological research tends to focus solely on the anatomical area of interest. We are developing a protocol using a uniform and explicit technique, so that the data can be analyzed and compared across disciplines. We pay particular attention to tissues that have evolutionary significance in their degree of variance like fat, skeletal muscle, brain weight, gastro-intestinal tract and bone. We include placental mammals, marsupials, and reptiles in our initial phase of data collection. This protocol will be utilized for ongoing comparative research.

Synapse Formation Is Modulated by a Molecular Hitch

Presenter: Erik Burlingame

Faculty Mentor: Philip Washbourne

Presentation Type: Poster 50

Primary Research Area: Science

Major: Biochemistry

Funding Source: Undergraduate Research Fellowship, Center on Teaching and Learning, $9369; UROP Mini-grant, Undergraduate Research Opportunity Program, $1000; McNair Scholars Program, TRiO, $13221; Swayne Family Scholarship, Swayne Family Foundation, $8800

Synapses are functional units of connectivity that permit the exchange of information between cells in the nervous system. As such, aberrant synapse formation is implicated in a host of neurodevelopmental disorders. Normal formation of synapses requires the transport, recruitment, and stabilization of the synaptic vesicle-regulating protein synapsin to nascent synapses. Recruitment of synapsin to nascent synapses is regulated by cyclin-dependent
kinase 5 (Cdk5), but the downstream effectors of Cdk5 that enable this recruitment remain elusive. Using a zebrafish model, our research examines a putative role of the scaffolding protein calcium/calmodulin-dependent serine kinase a (CASKa) in synapsin recruitment. The mammalian ortholog CASK participates in multipartite transport complexes and is localized to presynaptic terminals by Cdk5-mediated phosphorylation. These observations spurred our hypothesis that Cdk5 phosphorylates CASKa to recruit synapsin to presynaptic terminals. Using a stereotypical touch-evoked behavior to assess synapse function, we found that embryos misexpressing non-phosphorylatable CASK protein exhibit a significant reduction in touch response when compared to embryos expressing either endogenous CASKa or exogenous mammalian CASK protein. Immunofluorescent characterization of synapses from touch-sensitive neurons in these touch-insensitive embryos shows deficits in synapsin localization, further supporting a physical intersection of CASK and Cdk5 during synaptic development. With human CASK dysfunction being linked to defects in synapses, microcephaly, and X-linked intellectual disability, this examination may help establish a novel target for CASK-associated disorder remediation.

Novel Bacterial Protein AimA Promotes Mutualism by Increasing Commensal Fitness and Reducing Inflammation in the Host

Presenter(s): Lila Kaye − Biology, Emphasis In Cellular And Mollecular

Faculty Mentor(s): Karen Guillemin, Kristi Hamilton

Poster 50

Research Area: Microbiology

Funding: SPUR 2016, VPRI 2017, Meta, NIH

The microbiota of the gastrointestinal tract is critical for the development and regulation of the host immune system. Some bacterial genera are associated with health and homeostasis, while others have been linked to inflammation and disease. There have been many studies in recent literature investigating the potential role of commensal microbes in autoimmune and gastrointestinal diseases, both preventative and pathogenic. Much less is known, however, about how interactions with the immune system benefit resident microbes. Here I used the zebrafish, Danio rerio, as a powerful gnotobiotic model for investigating host-microbe symbiosis. I investigated the novel immunoregulatory protein aimA, produced by the zebrafish commensal Aeromonas, and show that it facilitates mutualism with the host by reducing gastrointestinal inflammation and increasing bacterial intestinal colonization in both monoassociations and co-inoculation with pro-inflammatory species Vibrio. Using GFP-tagged neutrophils as a reporter for inflammation, I showed that a deletion mutant lacking the gene for AimA (∆aimA) is unable to regulate host immune response and cannot colonize the gut as robustly. Inoculation into immunocompromised MyD88-/-hosts having decreased intestinal inflammation rescues the colonization defect suffered in the absence of aimA, demonstrating reciprocity between control of the host biology and control of the resident bacterial biology. Identification of bacterial products involved in establishing a healthy symbiosis with the host is crucial for understanding how commensal communities are assembled and maintained.

Niche Separation Between Three Sympatric Lemur Species at Berenty Reserve, Madagascar

Presenter(s): Erick Wonderly

Faculty Mentor(s): Frances White & Colin Brand

Poster 50

Session: Sciences

One of the central goals of ecology is to understand niche differentiation: how different species use the same environment in different enough ways so as to coexist. Typically, this is tested by examining dietary overlap between species. The Lemuriformes, lemurs and their relatives, provide an interesting test of niche differentiation given the antiquity of this superfamily and subsequent adaptation to various unoccupied niches. In this study we first tested for dietary overlap in feeding ecology among three lemur species: Ring-tailed lemur (Lemur catta), Verreaux’s sifaka (Propithecus verreauxi), and Brown lemurs (Eulemur fulvus rufus), at Berenty Nature Reserve, Madagascar. We also considered the degree to which species can monopolize a food source from other species. We analyzed 1,988.16 hours of feeding and social behavior data collected by Alison Jolly between 1988-89 and 1992-93. We found consistent, substantial overlap in the diets of all three lemur species across all four study periods. The majority of aggressive intergroup encounters were within species. Between species encounters rarely resulted in aggression and exclusion from a feeding patch. Collectively, these results suggest greater dietary overlap than previously considered in these taxa and that niche separation beyond lemurs occurs beyond feeding contexts.