Browsing by Subject "Integrated Biosciences"
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Item Acoustical conditioning of the common carp (Cyprinus carpio) as a potential management tool(2011-05) Sloan, Jami LynnClassical acoustic conditioning was investigated with the common carp (Cyprinus carpio) to determine its potential as a management tool. In small laboratory tanks (≤ 1000 L), groups of five juvenile carp were trained to associate a 400 Hz pure tone stimulus with a food reward. Following three days of training, the majority of fish showed a consistent and rapid (< 30 sec) ability to localize the sound source and receive the subsequent food reward. Six of the nine groups tested showed retention of the conditioned behavior for up to 5 months. Trials were then conducted in a 24,000 L outdoor pool to mimic more natural conditions. Carp again displayed relatively short learning curves and high accuracy (84.4%) in localizing the sound source. These findings indicate that carp are readily conditioned to an acoustic signal and are able to retain this behavior for months, suggesting that acoustical conditioning may be used as a management strategy in which the movement of wild carp can be manipulated for trapping and removal within a lake system.Item An assessment of the long-term phenology and impact of Bythotrephes longimanus in Island Lake Reservoir, Minnesota, using sediment records.(2012-01) Beranek, Ashley ElizabethBythotrephes longimanus, a predacious zooplankter, has invaded >130 inland lakes in North America, yet few studies have documented the long-term phenology and impact of an invasion. This study used Bythotrephes spines and Daphnia ephippia in 210Pb-dated sediment cores from four sites in Island Lake Reservoir (Minnesota, United States) to document the establishment and growth of the Bythotrephes population and to examine corresponding changes in daphnid species composition and density during a 40-year period spanning the invasion. Based on sediment evidence, Bythotrephes invaded the reservoir in 1982.2, or about 8 years prior to what was its first detection in the water column in 1990. If accurate, this makes Island Lake Reservoir the first documented inland lake invaded in North America. Year to year population density of Bythotrephes followed a logistic growth model, and generally took about 10 years to reach annual carrying capacity. A notable impact of Bythotrephes on the daphnid community occurred within the first few years but did not intensify with increased Bythotrephes density over time. Daphnid species composition shifted in the western basin toward D. mendotae dominance, but did not shift in the eastern basin. The reservoir maintained a population of its largest-bodied daphnid, D. pulex, despite Bythotrephes presence. Coincident with Bythotrephes invasion, mean daphnid ephippium size decreased both within species and for the whole 3-species daphnid assemblage. This research suggests that lakes could harbor Bythotrephes for years before its first detection in the water column, that annual population build-up of Bythotrephes may require years before reaching peak annual densities, that the impact of Bythotrephes on food webs occurs relatively quickly, and that long-term impacts of Bythotrephes in a reservoir may be less severe than in natural lake ecosystems.Item Autophagy enhancement as a target for mood stabilizing drugs.(2010-08) Poquette, Chelsey HannahAbstract summary not availableItem Characteristics of Post-Parturition Areas of Moose and Effective Temperature of Cover Types in Moose Home Ranges in Northeast Minnesota(2011-01) McGraw, Amanda MarieHabitat used in the 3-4 weeks after parturition could be important to calf survival. Newborn calves are vulnerable to predation, and the cow needs adequate forage reserves during the period when calf mobility is limited. VHF collared cows were located by helicopters up to 3 weeks after parturition. A post-parturition area was defined as 100 ha surrounding the cow/calf location. We determined cover type composition in post-parturition areas compared to the 95% kernel home ranges of moose. Buffers of 5, 10, 25 and 50 ha were created around post-parturition areas to determine cover type composition at smaller spatial scales. Post-parturition areas were also compared to equivalent areas surrounding cows without calves. Fidelity was measured by comparing distances between consecutive post-parturition locations to distances to random locations distributed within the home ranges. Post- parturition sites had more lowland conifer and shrubland or regenerating/young forest cover types than random locations within the home range. Cows with calves selected areas with larger proportions of lowland conifer, shrublands and regenerating forests than did cows without calves. These cover types could have been used for cover and for foraging, respectively. There was no difference in the amount of water available in post-parturition areas when compared to home ranges (3.5% ± 0.8). Distances between consecutive post-parturition locations (1.7 ± 0.4 km) were less than expected when compared to distances to random points within the home ranges (3.3 ± 0.4 km), indicating cows may exhibit a degree of fidelity to post-parturition areas.Item Characterization of UMD227 cells: a novel murine mammary cancer cell line.(2010-05) Redbrook, Shannon MarieBreast cancer is a heterogeneous disease, which makes it a challenging disease to treat. Breast cancer can be classified by histology as well as by molecular markers. In order to develop a relevant in vitro model, our lab has cloned and isolated a cell line, UMD227, from a mammary tumor of our mouse model which expresses transforming growth factor alpha under control of promoter, neu-related lipocalin (NRL-TGFα). When UMD227’s are transplanted back into our mouse model the resulting UMD227 tumors exhibit a higher grade than the primary tumor from which the cell line was derived and tumors following transplant have a distinct spindle cell like morphology, suggesting mesenchymal like characteristics. These characteristics suggest that this cell line represents basal-like tumor characteristics. My hypothesis was that the UMD227 cell line is a model of basal-like breast cancer. I began by determining the biological response of UMD227 cells to estrogens and antiestrogens in vitro and evaluation of marker proteins that distinguish mature differentiated epithelial cells from cells undergoing epithelial mesenchymal transition from progenitor/stem cells. My research concludes that the UMD227 cells are basal-like mammary gland cancer cells.Item Insulin-like growth factors and placental ischemia-induced hypertension in the pregnant rat.(2011-06) Bozadjieva, Nadejda IvanovaPreeclampsia is a gestational condition characterized by new onset hypertension and proteinuria and often results in fetal growth restriction. This pregnancy-specific condition occurs in ~8 percent of live birth pregnancies and is the leading cause of maternal and neonatal mortality and morbidity. Delivery is the primary therapeutic approach for preeclampsia; hence, the long-term goal of preeclampsia research is to determine what causes preeclampsia and to find treatments to alleviate maternal hypertension and extend pregnancy to improve fetal outcome. Chronic placental ischemia via the reduced uteroplacental perfusion pressure (RUPP) model, utilized in this project to mimic the preeclamptic condition during the third trimester in the pregnant rat, results in hypertension, intrauterine growth restriction and fetal loss. Insulin-like Growth Factors (IGF-1 and IGF-2) have been reported to play an important role in fetal development, and low plasma levels of IGF-1 have been associated with reduced endothelial function and have been closely linked with elevated blood pressure in non-pregnant subjects. The hypotheses tested in this project are that 1) placental ischemia induced by RUPP decreases circulating and placental levels of IGF-1 and IGF-2; and 2) administering exogenous IGF-1 in RUPP rats attenuates maternal hypertension, endothelial dysfunction, intrauterine growth restriction and fetal loss. The data show that chronic placental ischemia decreases circulating IGF-2 levels, but does not affect circulating IGF-1 or placental IGF-1, IGF-2 and IGF-1 receptor levels. Further, administering exogenous IGF-1 in RUPP rats during the third trimester attenuates blood pressure and decreases fetal loss, but does not improve endothelial function or fetal weight. Overall, these studies determined that the mechanisms that regulate IGF signaling are potential targets for improved therapies for treating maternal blood pressure in preeclampsia and gestational hypertension.Item Measuring habitat use by bats in northeastern Minnesota using acoustic methods.(2011-02) Abel, Rebecca LauraBaseline data on bat distribution and habitat use is essential for bat conservation. Little information exists on bats in the southern boreal forests of the Midwest. We measured summer bat habitat use and foraging activity at aquatic, linear corridor, and interior forest sites with bat detectors in deciduous, mixed-wood, and coniferous forests in northeastern Minnesota. We used three common acoustic bat activity indices to quantify acoustic bat data and we compared the results of each index. We further examined the indices to determine how differences among bat activity indices influence statistical inferences of bat activity. We measured the effects of relative insect abundance and degree of vegetation density on bat activity. We recorded all seven resident bat species across the study area. We recorded 7,666 identifiable bat calls during 1,440 detector hours in 2009. In 2010 we recorded 8,554 bat calls during 930 detector hours. Bat activity, dominated by Myotis species (Myotis lucifugus and M. septentrionalis), Lasiurus borealis, and Lasionycteris noctivagans, was concentrated at aquatic and linear corridor microsites, regardless of forest cover type. However, bats foraged at similar rates in each microsite type. Bat activity and foraging activity occurred earlier at interior forest sites relative to aquatic and linear corridor sites, suggesting that interior forest is also important habitat for bats as they leave day roosts to forage. Bat activity indices had clear biases, but resulted in similar statistical inferences of habitat use of northeastern Minnesota bat species.Item Predicting breeding habitat of the Connecticut Warbler (Oporornis agilis)(2010-05) Lapin, CarlyThe Connecticut warbler (Oporornis agilis) is an uncommon Neotropical migrant that breeds in the north-central United States and south-central Canada. Breeding populations of this species are reported to be declining. I analyzed habitat and landscape at three spatial scales (buffer radii of 100 m, 500 m, and 1,000 m) for 86 sites within 28 forest stands in northern Minnesota for Connecticut Warblers sampled over an 18-year period. I regressed combinations of habitat variables with two response variables, Connecticut Warbler abundance (the total number ever recorded at a site or stand) and Connecticut Warbler frequency (the number of years recorded out of 18 years) using a zero-inflated negative binomial distribution and logistic regression, respectively. A subset of models with #1;AICc ≤ 4.0 was retained and model-averaged predictions were calculated for each combination of buffer size and response variable. When comparing model-averaged predictions to observed data, the best models were those using Connecticut Warbler frequency at the 1,000 m buffer (r2 = 0.52). These models were used to create a map of predicted Connecticut Warbler breeding habitat in the two national forests sampled. At the 1,000 m scale, Connecticut Warblers were positively associated with large, simple patches of upland coniferous and lowland black spruce forest, and were negatively associated with upland deciduous forest.Item Seasonal abundance and movement of the invasive round goby (Neogobius melanostomus) on rocky substrate in the Duluth-Superior Harbor of Lake Superior(2011-01) Lynch, Michael PatrickAbstract not available.