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Interdisciplinary research is needed to study the effects of top-level predators on process, function, and resilience in marine ecosystems. The reintroduction of sea otters to southeast Alaska following their extermination in the 19th century fur trade provides an opportunity to study the structure of marine ecosystems along a gradient of occupation of a top-level predator. The expansion of sea otter populations in southeast Alaska has negatively impacted commercial, sport, and subsistence shellfish fisheries, but it is possible that sea otter colonization may benefit other fisheries because otters promote a diverse kelp-dominated ecosystem. Fishery species that rely on kelp for spawning, nursery, or adult habitat might be expected to benefit from sea otters. Ecological theory predicts that systems with top-level predators are more stable than those with top-level predators removed. We will investigate these processes by collecting ecological data using SCUBA survey techniques to study the effects of sea otter recolonization (no otters, recently colonized more than2 years, established more than 10 years, and established less than 20 years) on kelp, fish and invertebrate communities throughout southeast Alaska. Our interdisciplinary study will include local and traditional knowledge through semi-directed interviews on the abundance, distribution, and impacts of sea otter recolonization.
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CONTAMINANT ACCUMULATION IN NEOTROPICAL MIGRANTS DURING MIGRATIONAlejandra Maldonado, Miguel Mora.
Texas A&M University, College Station, TX.
It has been hypothesized that migratory birds accumulate their contaminant burdens while on their wintering grounds.
The purpose of this study was to determine seasonal variation of contaminant accumulation in migratory songbirds during migration. The potential for exposure differs among feeding guilds due to specific ways in which contaminants move through food webs. This project also aimed to evaluate the diet and trophic position of birds. Samples were collected from sites located in Texas, Mexico, and Costa Rica during the fall, winter, and spring migration periods.
Birds were analyzed for persistent organic pollutants. In addition, feather, liver, and stomach content samples were analyzed for stable isotopes of carbon and nitrogen to examine diet and trophic relations. Understanding Graduate
study can be used in conducting risk assessments of avian wildlife and incorporating this knowledge further into conservation efforts.
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EMPOWERING CLIFTON, ARIZONA, RESIDENTS THROUGH EDUCATION TO PROTECT THE SAN FRANCISCORIVER Berenise Rivera, Channah Rock.
University of Arizona, Tucson, AZ.
The Arizona Department of Environmental Quality (ADEQ) is a regulatory agency that maintains a 303d list of locations that do not meet clean water regulatory standards. As of 2008, ADEQ listed 17 impaired watersheds
293 GRADUATE POSTER ABSTRACTS
throughout the state of Arizona on the 303d list due to E. coli presence higher than the US EPA-set standards. The Gila River is listed on the 303d list, and it is comprised of the Upper Gila River Watershed from Coolidge Dam to the Arizona-New Mexico border and covers about 6,000 square miles. The objective of this study is to evaluate community perception on water quality of the San Francisco River in Clifton, Arizona, composed of about 56% Hispanic population. Preliminary survey results on water quality of the San Francisco River (SFR) consisted of 48% of people surveyed thinking the SFR has poor water quality for swimming. Also, the majority of respondents are concerned with poor water quality and their health. Sixty percent of people get information from the newspaper, factsheets, or brochures, and 52% of people get information from conversations with others. This presentation will describe the use of information, such as fact sheets/brochures on water quality and human health and a one-day workshop on basic microbiology, and the impact in community stewardship leading to behavior change. This data will be used to understand the interaction between research and the public to promote greater understanding of the issues that impact water quality and human health.
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USING CAENORHABDITIS ELEGANS AS A MODEL FOR OXYGEN-DEPRIVATION RELATED DISEASEAnastacia Garcia, Pamela Padilla.
University of North Texas, Denton, TX.
Oxygen deprivation is central to a number of human health issues including stroke and myocardial infarction, and there are numerous factors that predispose individuals to an increased risk of death from oxygen-deprivation related disease. These factors include obesity, diabetes, family history (genetic makeup), and age. To better understand the genetic and cellular pathways involved in the pathology of these combinatory stresses, we employed the model system C. elegans, a soil nematode. C. elegans is particularly well suited for this work given that it is a powerful genetic model system and has the ability to survive severe oxygen deprivation. In C. elegans, specific hallmarks of the disease process can be modeled through genetic and environmental manipulation in order to better understand the associations between genotype, diet, age, and oxygen deprivation responses. We are using C. elegans to examine how diet and genotype influence oxygen-deprivation response and survival. Wild-type, 1-day old C. elegans fed a normal diet are able to survive exposure to short-term (24 hrs) oxygen deprivation (anoxia). However, animals fed a glucose-supplemented diet show a significant reduction in survival in response to the same treatment, suggesting that glucose supplementation negatively impacts anoxia survival, and that a homeostatic balance of carbohydrate stores is important. Additionally, this diet-induced anoxia sensitivity can be modulated genetically and can be suppressed by mutations in genes in highly conserved pathways, including insulin-like signaling. Additional analysis will allow us to further characterize the specific genes and signaling pathways involved in anoxia survival on a high-carbohydrate diet.
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ALLELE-SPECIFIC PROTEIN EXPRESSION AND PHOSPHORYLATION IN A DIPLOID YEAST SPECIESWilliam Edelman, Samuel Lancaster, Judit Villen, Maitreya Dunham.
University of Washington, Seattle, WA.
Diploid organisms, such as humans, carry 2 copies of DNA: 1 from each parent, or 2 alleles for each gene. These alleles can harbor distinguishing divergent mutations. Diploid strains of the single-celled fungus, Saccharomyces cerevisiae, baker’s yeast, also carry copies in a similar way. We are interested in understanding how the expression of each parental copy is regulated. In this study, we use 3 yeast strains (S. cerevisiae, S. bayanus, and their hybrid) as a model. We measure relative protein abundances between the 2 parental strains and their hybrid descendant using mass spectrometry. We ask: what is the protein-allele specific expression in the hybrid? We report the relative abundance of each parental allele in the hybrid for ~1,400 proteins and determine to which functional proteins groups each belongs. We also measure the relative amounts of protein phosphorylation between S. cerevisiae, S. bayanus, and each allele in the hybrid species. Our work will shed light on how different species and individuals might vary in terms of protein regulation and signaling regulation.
294 GRADUATE POSTER ABSTRACTS
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GENOME INSTABILITY AS A NOVEL MOLECULAR MARKER FOR PHENOTYPIC ROBUSTNESSGrace Mason, Keisha Carlson, Christine Queitsch.
University of Washington, Seattle, WA.
Phenotypic robustness is the ability of organisms to develop into wild-type adults despite genetic and environmental perturbations. In the genetic model organism Arabidopsis thaliana, we have shown that decreasing robustness by inhibiting the protein chaperone HSP90 increases the penetrance and heritability of traits. Based on our data and similar observations in other diverse model organisms, we hypothesize that differences in robustness among humans may account for the variability in penetrance of disease alleles and the missing heritability of complex traits. Currently, we measure robustness by calculating the variance in a quantitative trait among many isogenic siblings. High variance of a trait indicates low robustness. In order to predict the effect and heritability of genetic variants in individuals and nonmodel organisms, our goal is to identify molecular markers that correlate with an individual’s robustness.
An excellent candidate for a molecular signature of robustness is genome instability. For example, in human cells, reduction of HSP90 increases mutation rates of microsatellites, and in fruit flies it increases transposon mobility. We demonstrate that reduced HSP90 activity, and thereby low robustness, in A. thaliana correlates with increased somatic homologous recombination and microsatellite slippage. By measuring robustness using traditional methods, we show that genome instability mutants in A. thaliana have lower robustness than wild-type plants. Therefore, genome instability can serve as a molecular marker for an individual’s level of robustness and potentially as a predictor for the penetrance of genetic variants in complex traits and disease.
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EXPLORING POPULATION GENETICS AND ESSENTIAL HABITAT OF SNOOK IN SOUTH TEXASAlin Gonzalez, Deborah Overath.
Texas A&M University-Corpus Christi, Corpus Christi, TX.
Snook (Centropomus spp.) were an important commercial fishery in South Texas until the population crashed in the late 1930s. As snook numbers increase again in South Texas, proper management of this growing fishery requires biologically pertinent information. Two important questions are, what is the genetic structure of snook, and are snook breeding in Texas waters? Currently such information does not exist. The overall goal of this project is to provide important baseline genetic data for snook in South Texas. Samples from adult snook and young-of-the-year (YOY) were collected and analyzed for 10 species-specific microsatellite markers using standard population genetic techniques and statistics. A sibship analysis will be performed on YOY to determine if they could have been produced by local adults, indicating a local breeding population. This project will also use geographic information system (GIS) methods to determine areas of high genetic diversity using the landscape genetics GIS toolbox. This approach will also indicate if clusters of siblings exist and if any clusters are genetically different from one another. With the results of this ongoing study, the utility of GIS maps will allow managers to locate areas of high genetic diversity and essential habitats.
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HSP90 AND AGO1 IN THE BUFFERING OF PHENOTYPIC VARIATIONTzitziki Lemus Vergara, Christine Queitsch, Jennifer Lachoweic.
University of Washington, Seattle, WA.
Robustness to genetic and environmental perturbations is a fundamental property of biological systems. Previous work has demonstrated the importance of the molecular chaperone HSP90 in maintaining organismal robustness.
Graduate Poster HSP90 inhibition reveals cryptic genetic and epigenetic variation with significant phenotypic consequences in flies, fish, plants, and yeast. The molecular mechanisms underlying the release of HSP90-dependent variation are not well understood. Recent studies found that microRNAs (miRNAs) are also important in maintaining robustness due to their function in modulating gene expression. In humans and flies, HSP90 is required for the formation of the miRNA-silencing complex. Moreover, in tobacco cell lines, HSP90 interacts physically with ARGONAUTE1 (AGO1), a key protein in the plant miRNA pathway, and a component of the miRNA-silencing complex. We hypothesize that HSP90 and miRNAs interact in maintaining organismal robustness in A. thaliana. Using established assays for HSP90 function, we demonstrate that HSP90 and AGO1 interact genetically in the buffering of phenotypic variation in early seedlings. Moreover, AGO1 polymorphisms correlate with sensitivity to HSP90 inhibition of divergent A. thaliana strains. Using expression analysis we showed that HSP90-AGO1 interaction in the buffering of variation is complex.
Currently, we are comparing AGO1’s buffering potential and breadth to HSP90 by crossing ago1 mutants into different
A. thaliana accessions. The A. thaliana Argonaute family is comprised of 10 members. Among these, we show that AGO10 and AGO5, the closest AGO1 paralogs, do not interact with HSP90. We are investigating whether other Argonautes interact genetically with HSP90.
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DELINEATION AND VALIDATION OF A TBX1 BINDING SITE ON GENOMIC DNARaquel Castellanos, Qing Xie, Deyou Zheng, Ales Cvekl, Bernice Morrow.
Albert Einstein College of Medicine, Bronx, NY.
TBX1 encodes a transcription factor that contains an evolutionarily conserved DNA binding domain termed the T-box that is shared with other family members. Haploinsufficiency or mutation of TBX1 is responsible for the etiology of DiGeorge syndrome but few direct downstream targets have been identified. All T-box proteins bind to similar but not identical consensus DNA sequences, indicating that there are specific binding preferences. Our hypothesis is that TBX1 has a preferential DNA binding sequence through which regulation of direct downstream targets occurs.