Browsing by Subject "Department of Biology"
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Item Accelerating Tuberculosis Drug Discovery by High Throughput Screening (2016-02-19)(2016) Arora, Kriti; University of Minnesota Duluth. Department of BiologyTuberculosis (TB) continues to be a leading killer of people worldwide infecting an estimated one-third of the world population and causing an 1.5 million deaths in 2014 alone. The current therapeutic regimen for drug-sensitive disease consists of 6-months of chemotherapy with agents that are associated with adverse events and toxicities leading to non-compliance. Additionally HIV-TB co-infection and the spread of drug-resistant TB underscores the need for discovery of new drugs that would shorten the course of chemotherapy. The Tuberculosis Drug Accelerator Program was born out of this urgent need and is a Gates Foundation funded collaborative effort between pharmaceutical companies and academic institutions. As part of this initiative we have conducted the largest global screening effort againstMycobacterium tuberculosis at the Tuberculosis Research Section (NIAID, NIH) in partnership with Merck, Bayer, AstraZeneca, EISAI, Pfizer and the University of Dundee. This screening campaign has generated several hit compounds which are currently progressing through our formal hit assessment cascade. The aim of the program is to increase early attrition rates so that only the best compounds move forward into preclinical development with the ultimate goal of declaring a new clinical candidate(s) by 2019 and a new regimen by 2024.Item Analyzing Plant Wax Profiles – Can Herbarium Species Serve As Proxies For Globally Distributed Plant Species?(2022) Lastovich, Jacob RPrevious research has showed qualitative and quantitative similarity of compounds in wax profiles of plants. The aim of this project showed that these trends continued across the plant kingdom.Item Appendices to: Assessment of Habitat Types and Bird Populations in the Duluth-Superior Harbor Area, September, 1977(1977-09) Niemi, Gerald J; Davis, Thomas; Kotar, John; Hofslund, PershingItem Assessment of Eurasian Phragmites australis Haplotype M Cryptic Invasion in the Minnesota and Mississippi River Valleys of Minnesota(2009-04-08) Weaver, RobbynPhragmites australis (Cav.) Trin. ex Steud. is an aquatic grass species found in wetlands throughout North America. The cryptic invasion of these environments by the introduced Eurasian Phragmites australis haplotype M over the past two centuries has recently been reported. In recent decades, the aggressive expansion of clonal Phragmites australis populations in many Minnesota wetlands has been noted. Wetland scientists have often speculated that these invasive populations may represent non-native strains that are morphologically indistinguishable from the native type, now recognized as Phragmites australis subsp. americanus. In this study, we use RFLP analysis to investigate the extent of Eurasian Phragmites australis haplotype M establishment in the Minnesota and Mississippi River Valley corridors of Minnesota, and within the drainage way of Interstate Highway 94 in central Minnesota.Item Autonomous Self-Fertilization and Limited Outcrossing in Linum sulcatum (2015-03-13)(2015) Jahnke, Matthew; University of Minnesota Duluth. Department of BiologyItem Behavioral differences in sound detection in recently diverged cave and surface forms of Astyanax mexicanus(2021) Kistner, Amanda R; Enriquez, Maya S; Michels, Noland O; Mensinger, Allen FAstyanax mexicanus, or the Mexican tetra, inhabits both surface streams and cave systems, and has subsequently developed two unique morphologies: a cave morph and a surface morph. Cave morphs of the species have evolved several troglomorphic phenotypes, including vestigial eyes, reduced pigmentation, and increased olfactory and lateral line sensitivity. Interestingly, several satellite populations of surface fish were introduced to a Texas aquifer approximately 100 years ago and, following cave colonization, rapid evolution of various sensory adaptations between the cave and surface populations have been observed. Auditory evoked potential (AEP) data was collected to compare hearing sensitivities between cave and surface satellite populations, and both populations responded to sound presentation up to 4 kHz. However, because AEPs measure action potential summation to screen for frequency sensitivities, behavioral data is needed to determine absolute hearing sensitivity. The current study examines behavioral differences in sound detection between these two populations using reflexive startle behaviors to sound, namely the “C-start” escape response, which has been shown to be a reliable means of determining neurological responses to acoustic stimuli. Based on behavioral audiograms collected on satellite three populations, San Pedro Springs (cave) and Honey Creek (surface) appear to respond more readily to acoustic stimuli and habituate at a similar rate when compared to San Antonio Zoo (surface), which appear to respond less readily and habituate faster. Differences in sound pressure thresholds, as well as stimulus-response latencies between these populations, will be determined through finer volume control and modeling sub-thresholds.Item BioChat (2003-12)(University of Minnesota Duluth, 2003-12) University of Minnesota Duluth. Department of BiologyItem Biogeochemical and food web studies in lakes large and small (2019-10-11)(2019) Ozersky, Ted; University of Minnesota Duluth. Department of BiologyMy lab studies the ecology and biogeochemistry of lake ecosystems. In this talk I will highlight three research projects that my students, collaborators and I have been pursuing over the past five years. First, I will discuss our work on the way invasive zebra and quagga (dreissenid) mussels affect thebiogeochemistry of invaded lakes and how the impacts of dreissenids change with environmental setting. I will also describe our work on uncovering the seldom-studied ecological processes that occur during the winter in small and large ice-covered lakes. The third project I will present examines environmental controls on growth of benthic algae in large lake ecosystems, including the Laurentian Great Lakes and Russia’s Lake Baikal. I will finish by discussing my plans for future research.Item Bloated Rhizobia: The effect of PHB storage on Bradyrhizobium japonicum mortality during desiccation(2011-04-13) Underbakke, KyraSoil bacteria known as rhizobia infect the roots of legumes, forming nodules, where they benefit the host by fixing atmospheric nitrogen into a usable form for the plant. In return, these rhizobia use plant-derived energy to reproduce, and many species accumulate large quantities (>50% cell dry weight) of the storage lipid poly-3-hydroxybutyrate (PHB). Since high PHB stores give rhizobia up to a threefold reproductive advantage over cells with low PHB during starvation conditions, genotypes of rhizobia that are able to escape from nodules with more PHB would be expected to increase in frequency through time. However, not all strains of rhizobia synthesize large amounts of PHB. This research investigates a potential disadvantage to storing too much PHB: rhizobia that accumulate excessive amounts of PHB may be more likely to die in a drought environment. Using soybean (Glycine max) as host plants, I extracted Bradyrhizobium japonicum from nodules, desiccated the rhizobia, and measured PHB and percent of cells killed by this treatment using flow cytrometry. The results showed a positive correlation between PHB storage and percent killed by desiccation, indicating that high PHB storage may not always be selected for in rhizobial populations, despite its reproductive advantages.Item BURST and SURP Poster Presentations (2021-08-06)(2021) University of Minnesota Duluth. Department of Biology; University of Minnesota Duluth. Department of Chemistry and BiochemistryStudents in the Biology Undergraduate Research in Science and Technology (BURST) and the Chemistry and Biochemistry Summer Undergraduate Research Program (SURP) will present the research they have been working on with faculty mentors throughout the summer. There will be an awards ceremony for both programs to follow.Item Cascades and Connectivity: The Influence of Spatial Scale on Understanding Ecosystem Processes (2015-02-27)(2015) University of Minnesota Duluth. Department of Biology; Nibbelink, Nate; Hrabik, TomDr. Nate Nibbelink of the University of Georgia speaks on Cascades and Connectivity: The Influence of Spatial Scale on Understanding Ecosystem ProcessesItem Chemical Evolution: How Survival of the Fittest Applies to Molecules and Leads to Life (2016-02-12)(2016) Shaw, George; University of Minnesota Duluth. Department of Earth and Environmental Sciences; University of Minnesota Duluth. Department of BiologyItem Chromatin/Nuclear Architecture Roles in Chromosome Structure and Function (2021-01-15)(2021) Johansen, Kristen; University of Minnesota Duluth. Department of BiologyAlthough early paradigms for regulation of gene expression focused almost exclusively on transcription factor binding and recruitment of the RNA polymerase, we now know that gene expression levels can be exquisitely calibrated by chromatin structure and nuclear architectural influences. And although histone modifications were first described as a "code" linked to "active" or "silent" chromatin states, work in my lab and others are revealing how these marks play a much more dynamic role in modulating gene function and chromosome behavior. In this presentation I will propose a model for enzymatic and non-enzymatic mechanisms by which the JIL-1 H3S10 kinase influences chromatin structure and chromosome architectural organization, and discuss developmental and physiological consequences of JIL-1 dysfunction.Item Coordinated response efforts to the red swamp crayfish invasion in Michigan, U.S.A. (2020-10-09)(2020) Roth, Brian; University of Minnesota Duluth. Department of BiologyNative to the southeastern United States, red swamp crayfish (Procambarus clarkia) currently have a near-global distribution as a consequence of purposeful and accidental introductions. Their effects in invaded ecosystems are often dramatic, and include negative effects on native amphibians, macrophytes, water quality, and native crayfish species. Red swamp crayfish construct extensive burrows and are demonstrated to undermine water control structures and enhance erosion in invaded systems. In July of 2017, red swamp crayfish were confirmed in several waterbodies in Michigan including a natural lake, residential ponds, and golf course waterways. Their discovery led to the development of a multifaceted and coordinated response plan involving MSU along with multiple state and federal agencies. This response plan includes early detection, genetic determination of source populations, life history studies, and the evaluation of novel and traditional control methodologies. Crayfish are notoriously difficult to eradicate, and little information exists on red swamp crayfish invasions at this latitude to guide eradication efforts. As a consequence, our research provides the unique opportunity to inform efforts to control this species around the world. This seminar will provide an overview of the red swamp crayfish invasion in Michigan and will detail the coordinated effort to eradicate this species in the state.Item Cortical representations of social deficits gated by cerebellum dysregulation (2021-03-05)(2021) Yang, Amy; University of Minnesota Duluth. Department of BiologyPatients who suffer neuropsychiatric disorders, including autism, schizophrenia, depression and Alzheimer's disease, often show abnormal social interaction. Therefore, it is important to understand the neural basis of social behavior in search of innovative treatments. Emerging evidence suggests that the cerebellum plays a key role in the neural networks essential for social functions. To investigate the mechanisms, we manipulated the cerebellar activity in a mouse model by precisely controlling the firing of a distinct population of neurons. This manipulation specifically impaired remembrance of previously encountered conspecifics, i.e., social recognition memory. We furthered [sic] delineated the anatomical and functional connections between the cerebellum and the cerebrum that mediate social memory. These insights will help develop clinical interventions for mental illness.Item Darwin's Passion for Plants (2021-02-05)(2021) Moran, Robbin; University of Minnesota Duluth. Department of BiologyAfter the Origin of Species was published in 1859, Charles Darwin wrote six books completely dedicated to plants. This talk briefly describes what those books contains [sic] and why they were important. Did you know that Darwin was the first scientist to demonstrate that some plants attract, trap, and digest insects? Come hear about Darwin and plants - you won't think of him as a [sic] just a zoologist anymore.Item Developing Science Identities in Undergraduates Underrepresented in the Sciences (2014-10-24)(2014) Prunuske, Amy; University of Minnesota Duluth. Department of BiologyItem The Development of Round Goby Bioacoustic Traps(2011-04-13) DeMars, JosephIntroduced to the Laurentian Great Lakes via ballast water from trans-Atlantic voyages by 1990, the round goby (Neogobius melanostomus) joined the list of invasive species in the Duluth-Superior harbor in 1995. The round goby is a relatively small and aggressive benthic fish, which directly competes with native species for resources and habitat. One of the reasons for the round goby’s success as an invader is its reproductive strategy, which includes multiple spawning events within the spawning season and a nest-guarding male that uses vocalizations to attract females. In addition, round gobies will prey upon the eggs of native fish, such as lake trout, Salvelinus namaycush (Chotkowski and Mardsen 1999, Jonas et al. 2005, Fitzsimons et al. 2006), lake sturgeon, Acipenser fulvescens (Nichols et al. 2003) and smallmouth bass, Micropterus dolomieu (Steinhart et al. 2004). The round gobies’ aggressive behavior and reproductive strategy, has led to direct competition with native species and has enabled them to become a major component of the benthic community in the Laurentian Great Lakes. Fortunately, the goby’s vocalizations can be used to attract females for removal, decreasing reproductive success and releasing pressure on native fish. Preliminary trials conducted in August of 2010, showed female phonotaxis to low frequency stimuli. However the number of female gobies entering the trap (standard wire mesh minnow trap) needs to be increased for this new method to be practical. The objective of this project was to develop a fish trap that would increase the capture and retention rate of the round goby.Item Dissemination of RasV12-transformed cells requires the mechanosensitive channel Piezo (2020-09-11)(2020) Lee, Jiae; University of Minnesota Duluth. Department of BiologyDissemination of transformed cells is a key process in metastasis. Despite its importance, how transformed cells disseminate from an intact tissue and enter the circulation is poorly understood. Here, we use a fully developed tissue, Drosophila midgut, and describe the morphologically distinct steps and the cellular events occurring over the course of RasV12- transformed cell dissemination. Notably, RasV12-transformed cells formed the Actin- and Cortactin-rich invasive protrusions that were important for breaching the extracellular matrix (ECM) and visceral muscle. Furthermore, we uncovered the essential roles of the mechanosensory channel Piezo in orchestrating dissemination of RasV12-transformed cells. Collectively, our study establishes an in vivo model for studying how transformed cells migrate out from a complex tissue and provides unique insights into the roles of Piezo in invasive cell behavior.Item "Diversity, diversification, and the genomic basis of evolution in perennial crops and their wild relatives", a Seminar by Dr. Allison Miller Assoc. Professor, Saint Louis University (2014-04-11)(2014) Miller, Allison; Gross, Briana; University of Minnesota Duluth. Department of BiologyThe long-term goals of my research are to advance understanding of perennial plant evolution to better inform sustainable agriculture, crop improvement, and the conservation of plant genomic resources.