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THE EFFECTS OF CU2+ BINDING ON THE GLOBAL STRUCTURE OF THE PRION PROTEINAracely Acevedo, Eric G.B. Evans, Glenn Millhauser.
University of California, Santa Cruz, Santa Cruz, CA.
Prion diseases, or transmissible spongiform encephalopathies, are fatal, neurodegenerative diseases of animals and humans and include mad cow disease (BSE) and Creutzfeldt-Jakob disease (CJD). Prion diseases arise from a misfolded form of the prion protein (PrPC), a membrane-anchored protein found in the central nervous system of all mammals. PrPC contains four conserved octarepeat sequences (PHGGGWGQ) at the N-terminal domain that specifically bind Cu2+ ions. Although the specific coordination features of PrP Cu2+ -binding have been well characterize, the effects of metal binding on the global structure of PrP, and how these metals contribute to PrP function and prion disease are not known. The objective of this study is to determine the global structure of the prion protein upon binding of Cu2+ to the octarepeats and study the structural rearrangements. Preliminary data suggests that PrP undergoes a conformational change when bound to Cu2+ in which the Cu2+ -bound octarepeat domain interacts with the structured C-terminal domain. Using site-directed spin labeling combined with electron paramagnetic resonance (EPR) and double electron electron resonance (DEER) spectroscopy, we seek to characterize this global structural change. Specifically, we will measure intramolecular distances between nitroxide spin labels and natively bound Cu2+ ions. The results should hopefully provide a better understanding of the effects of metal binding on PrP structure and misfolding during prion disease. Having new insights on the effects of metal ions on PrP structure may lead to the discovery of drugs that will target these untreatable neurological diseases.
CHARACTERIZATION OF ZNF217 AND ITS ROLE IN BREAST CANCER USING BIOINFORMATICSJustin Ryan Salazar, Seth Frietze.
Northern New Mexico College, Espanola, NM.
Aberrant gene expression is a distinct characteristic of disease. Regulating gene expression is a complex and very specific process in which transcription factors, epigenetic mechanisms, and histone modification play essential roles.
Zinc finger domain-containing proteins (ZNFs) represent the single largest family of transcription factors encoded in mammalian genomes. However, their functions and genomic targets have remained poorly characterized. In this project we will attempt to define the function of ZNF217 in association with breast cancer by mining available genomic datasets. We aim to identify the ZNF217 DNA binding sites using motif-searching tools and to identify ZNF217 gene targets and colocalizing epigenetic marks. Overall, by using publically available datasets, genomic tools, and hypothesis-driven questions, we will begin to address the role of this transcription factor in breast cancer development.
PATTERNS OF CRYPTIC AND APOSEMATIC COLORATION IN COSTA RICAN MOTHSVicky Giese1, Ross Miller2.
California Polytechnic University, Santa Maria, CA, 2University of Guam, Mangilao, GU.
Cryptic patterns and aposematic coloration in moths was examined at 2 biological research stations in Costa Rica:
2 locations within Las Cruces and 1 in Las Alturas. In recent years, moths have become a focus of interest as a bioindicator species. Las Cruces is located in one of the most deforested counties in Costa Rica and is virtually a forest island consisting of 250 hectares (ha) and surrounded by mixed-use agriculture. In contrast, Las Alturas is located in a 10,000 ha preserve that has received minimal disturbance and is mostly primary rainforest. The purpose of this study was to see if there were differences in moth types between sites. Moths were attracted using a black light suspended in front of a white cotton sheet at each location. The black light was turned on at dusk and off at day break. Moths were collected and photographed at each location every evening at 8:00 p.m. and each morning at 6:00 a.m. Photographic images of moths were sorted into categories based on shape and color. Thirty different categories of moth types were designated in this study based on similarities, each representing a family. Species accumulation curves displayed the number of new moth types collected over time at each location to determine when sampling was adequate. Differences between the numbers of moth types in the categories and between collection sites were tested using chi-square analysis and were statistically significant at P 0.05. Statistical differences were expected because of variations in habitat at each location.
ECOLOGICAL CONSIDERATIONS OF PREDATOR AND PREY POPULATION DYNAMICS DESCRIBED BY A
MATHEMATICAL MODELHasan Sumdani, Matthew Le, Martin Tran, Samuel Frickle, Hristo Kojouharov.
University of Texas at Arlington, Arlington, TX.
The purpose of this study is to represent the dynamical patterns of a protist preying on living and deceased bacteria using a mathematical model. Three differential equations are used to represent the numbers of protists, living bacteria, and deceased bacteria in the system. The model takes into account parameters that affect both the rate at which live bacteria and dead bacteria are consumed and how this consumed material aids in the protist’s growth.
Parameters in this model include an encounter rate between the prey and predator and the rate of consumption of the prey by the predator. The encounter rate can be derived from the speed that both organisms move. The faster they move, the more likely they are to encounter one another. Another important parameter in this model is the conversion constant, which describes how much a protist can reproduce with each bacterium ingested. The results show that changing the different parameters can lead to different, biologically meaningful scenarios, such as an overall decrease in the protist population despite a high consumption rate. The different scenarios that this model can predict show it is an effective predator/prey model for microbial systems. The simplicity of the model makes it a valid starting point for more complicated predator prey systems.
INFLUENCE OF AN INVASIVE PLANT ON MESOPREDATOR FORAGING ACTIVITY IN THE COASTAL DUNES
OF NORTHERN CALIFORNIAYvan Delgado de la Flor, Dr. Matthew Johnson.
Humboldt State University, Arcata, CA.
In the coastal dunes of northern California, the ecosystem has been altered by the presence of the invasive plant European beachgrass, and mesopredators and rodents experience the impact in their local habitats. We hypothesize that mesopredators spend more time foraging in areas where the invasive beachgrass is present and therefore rodents are more abundant. The aim of this study is to quantify the foraging activity of mesopredators and record their occurrence in two different habitats: dunes with beachgrass and dunes with no beachgrass. We are interested in the frequency of detection of mesopredators in the dunes and comparing their detection rate in the two different habitats.
Also, we will be looking for the species richness in the two areas. We deployed a total of 20 night-vision Bushnell cameras in a line transect with 10 video cameras placed in an area with beachgrass and another 10 cameras in an area without the invasive beachgrass. Each camera was mounted on a pole (one meter sunk in the sand and one meter above the sand) with a distance of 100 meters between each camera. Data collection started the last week of
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March and will continue for six consecutive days every month from March until November. We will have 80% of our data collected before the SACNAS National Conference. Wildlife managers do not yet have a good understanding of mesopredators’ foraging activity in invaded or restored dune habitats, and this project will provide us with a better understanding of how invasive plants affect ecosystems.
MAGELLANIC WOODPECKER (CAMPEPHILUS MAGELLANICUS) BEHAVIOR WHEN APPROACHED BY
HUMANS IN THE CONTEXT OF ECOTOURISMIrán Román, Jaime Jiménez, Ricardo Rozzi.
University of North Texas, Denton, TX.
The Cape Horn Biosphere Reserve in southern Chile has increasingly drawn the attention of tourists. Ecotourism is an important activity of the region with various potentially detrimental ecological impacts. Since 2005, the Magellanic Woodpecker (Campephilus magellanicus) has been considered the emblematic species of this region. This bird is one that many people want to get a chance to see when visiting the Sub-Antarctic forests. This study assesses impacts of ecotourism on the Magellanic Woodpecker by experimentally recording this bird’s behavior when exposed to a motionless observer as opposed to tourists’ movements trying to observe birds closely. We compared the woodpecker’s foraging behavior and space use under these two settings and tested the hypothesis that woodpeckers get accustomed to people being close on repeated exposure. We found that disturbed woodpeckers significantly use higher parts of trees, forage on more substrates per hour, continuously move away from the observer, fly further apart when switching trees, and peck less on trees, thus decreasing feeding rate, compared to undisturbed individuals.
Repeated exposure to ecotourists can accustom woodpeckers to people and soften behavioral differences between these two contexts. Results indicate that under the proper conditions, woodpeckers can tolerate human behaviors that could have been initially disturbing. Our findings demonstrate that uncontrolled ecotourism affects Magellanic Woodpeckers negatively by lowering their energy input (i.e., fitness) when followed and continuously observed.
Results also suggest that woodpecker ecotourism is an activity that can be sustainable if ecotourists are told how to behave when observing Magellanic Woodpeckers.
SIZE-FREQUENCY DISTRIBUTIONS OF JUVENILE COHO SALMON (ONCORHYNCHUS KISTUCH) IN
STREAMS OF VARYING THERMAL REGIMES IN THE COPPER RIVER DELTA, ALASKAKeith Parker1, Michael Portman2, Gordie Reeves3,4.
Humboldt State University, Arcata, CA, 2School of Medicine, University of Washington, Seattle, WA, 3Pacific 1 Northwest Research Station, University of Oregon, Eugene, OR, 4US Forest Service, Portland, OR.
The Copper River Delta (CRD) in Alaska is the largest contiguous wetland on the Pacific Coast and supports strong populations of Coho salmon. Coho salmon sustainability depends in part on freshwater production of juveniles and is driven primarily by three factors: water temperature, body size, and food intake. Coho in the CRD use diverse streams representing thermal heterogeneity and potential patterns of food availability. Complex issues arise in explaining size-frequency distributions at large spatial scales and temperature regimes because of increased biotic and abiotic geographical complexities. We sought to determine if the size-frequency distribution of juvenile Coho salmon in the CRD differed between streams with contrasting thermal regimes. Young-of-year Coho salmon were collected and measured in two streams representing different thermal regimes. Gastric lavage and invertebrate sampling was performed for diet analysis. Streams included strong (25-Mile Creek) or weaker (18-Mile Creek) groundwater influences. Thermal regimes quantified across 2010 - 2011 indicated 18-Mile Creek was colder in the winter yet warmer in summer (range = 0 – 14 °C) relative to 25-Mile Creek (range = 2 – 6 °C), where groundwater presumably moderates seasonal thermal variability. Results indicate juvenile Coho in 18-Mile Creek were significantly smaller (33 mm fork length +/- 0.2) relative to fish in 25-Mile Creek (38 mm +/- 0.4). The smaller mean length of juvenile Coho in 18-Mile Creek is strongly associated with the contrasting thermal regimes. This study is part of a larger effort to evaluate the effects of global climate change on food availability, local physical habitat conditions, and timing of reproduction in streams of the CRD.
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Biological Sciences FRI-520
A LATITUDINAL EXAMINATION OF METACARCINUS MAGISTER (DUNGENESS CRAB) MEGALOPAE AND
SETTLER RECRUITMENT ON THE CENTRAL CALIFORNIA COAST THROUGH TIME-SERIES ANALYSISGriffin Srednick, Corey Garza.
California State University, Monterey Bay, Seaside, CA.
The mechanisms that drive population variability in marine systems are a prime research area for ecologists. In particular, understanding the impact variation in larval recruitment on marine populations can enhance our basic understanding of how populations are regulated and in turn can be used to inform the management of ecologically important marine species. In this study, a time-series analysis of megalopae and settler recruitment was conducted at Moss Landing, California, beginning in early March 2013 to assess abundance of larval Metacarcinus magister to inform fishery management. Light traps were used to collect crab megalopae and settlers daily within the Moss Landing harbor to examine expected fluctuations in recruitment numbers. Tidal, wind, and temperature data were collected and used to test for possible correlations with megalopae and settler abundance. Fluctuations in megalopaesettler ratio were observed from early March through June and were consistent with the M. magister larval cycle.
Specimens were collected and sorted to ensure proper identification and then placed in ethanol for preservation for
California Department of Fish and Wildlife records. Similar studies were conducted in three other California sites: