Digital Commons Network^™

Warm Springs, Early Lay Dates, And Double Brooding In A North American Migratory Songbird, The Black-Throated Blue Warbler, Andrea K. Townsend, T. Scott Sillett, Nina K. Lany, Sara A. Kaiser, Nicholas L. Rodenhouse, Michael S. Webster, Richard T. Holmes

Dartmouth Scholarship

Numerous studies have correlated the advancement of lay date in birds with warming climate trends, yet the fitness effects associated with this phenological response have been examined in only a small number of species. Most of these species–primarily insectivorous cavity nesters in Europe–exhibit fitness declines associated with increasing asynchrony with prey. Here, we use 25 years of demographic data, collected from 1986 to 2010, to examine the effects of spring temperature on breeding initiation date, double brooding, and annual fecundity in a Nearctic - Neotropical migratory songbird, the black-throated blue warbler (Setophaga caerulescens). Data were collected from birds breeding at …

The Degeneration Of The Human Mind: An Analysis Of Alzheimer’S Disease, A Kuhnian Perspective, Genevieve Ilg

Spring 2013, Kuhn's Philosophy of Science

In 1906, a German physician, Dr. Alois Alzheimer, specifically identified a collection of brain cell abnormalities (and the formation of plaque in the brain) as a disease, which forever changed the way scientists view degenerative cognitive disorders. Today, this brain disease bears his name, and is one of the most common diseases among the aging population. The discovery of Alzheimer’s Disease (AD) can be seen as a revolutionary, paradigmatic shift in regards to scientific discovery from a Kuhnian perspective. In that vein, the discovery presents philosophical implications for the notion of personhood and how those suffering from AD are treated …

The Antibiotic Revolution, Alyssa Olsen

Spring 2013, Kuhn's Philosophy of Science

In 1928, Alexander Fleming discovered Penicillin, which revolutionized the way infections were treated. This discovery was revolutionary because it impacted the scientific field, the medical field, the pharmaceutical industry, and all of humanity. Alexander Fleming’s discovery of Penicillin sparked the development of antibiotics, which has continued to save people’s lives since the revolution. Thomas Kuhn would qualify the discovery of Penicillin by Alexander Fleming as a revolution because it led to a paradigm shift. Prior to the discovery of Penicillin, patients died from trivial injuries and infections. Fleming’s discovery of Penicillin is revolutionary because it changed the worldview of the …

Differences In Alkaloid Defenses In The Poison Frog Oophaga Pumilio Between Disturbed And Undisturbed Habitats Of Bocas Del Toro, Panama, Yaritbel Torres-Mendoza

Senior Honors Projects

Poison frogs have the ability to sequester and store alkaloids in their skin as a mechanism of defense against predation. Alkaloids in poison frogs are obtained exclusively from the consumption of alkaloid-containing arthropods. As a result, changes in the environment can potentially harm Oophaga pumilio by altering their source of chemical defense. To date, only two conflicting studies have examined the effects of habitat disturbance on poison frogs chemical defenses. In the present study the effects of habitat disturbance on populations of O. pumilio from Colon and Solarte Islands, Bocas del Toro archipelago in Panama is examined. In addition, an …

Diagnosis And Prevention Of Metabolic Diseases In Drosophila Melanogaster, Claire Marie Coogan

Collection of Engaged Learning

No abstract provided.

Plant-Pollinator Interactions Over 120 Years: Loss Of Species, Co-Occurrence, And Function, Laura A. Burkle, John C. Marlin, Tiffany M. Knight

Biology Faculty Research

Using historic data sets, we quantified the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA. We found degradation of interaction network structure and function and extirpation of 50% of bee species. Network changes can be attributed to shifts in forb and bee phenologies resulting in temporal mismatches, nonrandom species extinctions, and loss of spatial co-occurrences between extant species in modified landscapes. Quantity and quality of pollination services have declined through time. The historic network showed flexibility in response to disturbance; however, our data suggest that networks will be …

Persons As Plants: Ecopsychology And The Return To The Dream Of Nature, Monica Gagliano

Landscapes: the Journal of the International Centre for Landscape and Language

Abstract. In this article, I examine human-plant perceptions and interactions in terms of developing a new perspective on the perception and the actions of people towards plants. By combining my scientific understanding of the biological world and my own experiences working with plant shamans, storytellers and mystics from around the world, I engage with the idea that the hierarchical structure by which Western science defines the variety of life forms as ‘primitive’ or ‘more evolved’ is at the root of the current environmental crisis and I argue that the solution to it rests in a change of this very perspective.

Multiple Breast Cancer Cell-Lines Derived From A Single Tumor Differ In Their Molecular Characteristics And Tumorigenic Potential, Goar Mosoyan, Chandandeep Nagi, Svetlana Marukian, Avelino Teixeira, Anait Simonian, Lois Resnick-Silverman, Analisa Difeo, Dean Johnston, Sandra R. Reynolds, Daniel F. Roses, Arevik Mosoian

Publications and Research

Background Breast cancer cell lines are widely used tools to investigate breast cancer biology and to develop new therapies. Breast cancer tissue contains molecularly heterogeneous cell populations. Thus, it is important to understand which cell lines best represent the primary tumor and have similarly diverse phenotype. Here, we describe the development of five breast cancer cell lines from a single patient’s breast cancer tissue. We characterize the molecular profiles, tumorigenicity and metastatic ability in vivo of all five cell lines and compare their responsiveness to 4-hydroxytamoxifen (4-OHT) treatment. Methods Five breast cancer cell lines were derived from a single patient’s …

Dictyostelium Development Shows A Novel Pattern Of Evolutionary Conservation, Xiangjun Tian, Joan E. Strassmann, David C. Queller

Biology Faculty Research

von Baer's law states that early stages of animal development are the most conserved. More recent evidence supports a modified "hourglass" pattern in which an early but somewhat later stage is most conserved. Both patterns have been explained by the relative complexity of either temporal or spatial interactions; the greatest conservation and lowest evolvability occur at the time of the most complex interactions, because these cause larger effects that are harder for selection to alter. This general kind of explanation might apply universally across independent multicellular systems, as supported by the recent finding of the hourglass pattern in plants. We …

Regulation Of Antigenic Variation In Trypanosoma Brucei, Imaan A. Benmerzouga

ETD Archive

Trypanosoma brucei is a protozoan parasite that causes sleeping sickness in humans and nagana in cattle. When inside the mammalian host, T. brucei cells stay in extracellular spaces and regularly switch their surface antigen, Variant Surface Glycoprotein (VSG), to escape the host's immune responses. To ensure the effectiveness of VSG switching, T. brucei expresses a single type of VSG at any time exclusively from one of 20 identical VSG expression sites located next to the telomere. Monoallelic expression of VSG and VSG switching are important for T. brucei's pathogenesis. Our major goal is to understand the mechanisms of antigenic variation …

Interpreting Biological Similarity: Ongoing Challenges For Diverse Decision Makers, Sarah M. Cork

Michigan Telecommunications & Technology Law Review

Similarity is an elusive and complicated concept facing comparisons of biological molecules, as even minute changes to a molecule's structure can dramatically affect its function in the body. Yet the flood of biologic drugs on the market will increasingly force these similarity comparisons. These concerns are particularly relevant to two groups of drugs: families of biologic drugs that closely resemble each other in structure and function, here termed "similar-impact biologics," and the biosimilars, which are intended to closely approximate generic forms of biologic drugs. In bringing biologic drugs to the market, manufacturers are likely to face dual obstacles: FDA approval …

A Comparison Of Water Availability In Coastal Live Oak (Quercus Agrifolia) And California Bay (Umbellularia Californica) At Top And Bottom Of Hillsides At Malibu Creek State Park, California, Jake Szarzynski, Marley Biyendolo, Jeremy Goldenetz, Ann Alcazar

Featured Research

This investigation serves to show whether moisture content is different in plants at the top of hills versus bottom of hills, specifically comparing values of Quercus agrifolia and Umbellularia californica in Malibu Creek State Park. By acquiring six branches of each species on a hill at intervals of twenty feet, the moisture content can be obtained and analyzed by using the Scholander Hammel pressure chamber. This allows us to determine whether there is a correlation between moisture content and plant position on hills.

Impact Of Reclaimed Water On Photosynthetic Performance In Green Bark Ceanothus (Ceanothus Spinosus), Erika De Leener, Michael L. Gribble, Joshua D. Volkmar, Luo J. Zhao

Featured Research

The sprinkled water on the campus of Pepperdine University is primarily reclaimed water from sinks, toilets and showers on campus. The water is treated with micro bacteria and sand rocks to remove larger particles, smaller nitrogen containing compounds, excess nutrients and human pathogens. The Mediterranean weather in Southern California is characterized by dry summers, and watering plants by reclaimed water helps relieve the water stress in the community. However, the reclaimed water might distort the normal physiology of native plants on campus. We hypothesize that because nitrogen containing compounds cannot be efficiently removed by micro bacteria, higher nitrogen content in …

Singing Behavior And Geographic Variation In The Songs Of The Veery (Catharus Fuscescens) Across The Appalachian Mountains, Courtney L. Brennan

ETD Archive

The Veery (Catharus fuscescens) is a common Neotropical migrant thrush whose breeding distribution spans the Northern United States and southern Canada and continues south through the high elevations of the Appalachian Mountains. Despite its wide distribution, many aspects of Veery biology are largely unknown, including a clear characterization of song and knowledge of geographic song variation. I describe the song structure, repertoire size, and patterns of song delivery in the songs of the Veery and describe geographic song variation across four regions along the Appalachian Mountains. Visual analysis of song spectrogram images of territorial males revealed that Veeries' repertoire ranges …

Bioinformatic Analysis And In Vitro Expression Of Malaria Parasite Translocon And Ribonuclease Binding-Like Rhoptry Genes, Moses Z. Timta

ETD Archive

Malaria caused by the parasite Plasmodium, still remains a significant public health problem worldwide, due to lack of a vaccine and emerging drug and insecticide resistance, among malaria parasites and mosquito vectors, respectively. Rhoptry proteins of Plasmodium enable merozoite invasion of host erythrocytes. However, only a few of these proteins have been characterized. Thirty-six P. yoelii merozoite rhoptry proteins were identified as putative rhoptry proteins by proteome analysis. Some of these proteins have been characterized while others still remain an intense area of active research. Molecular characterization and understanding of these novel proteins may assist in vaccine development, design of …

The Evolution Of Ungulate Locomotion Utilizing Extant Taxa For Reconstrucing The Movement Of Extinct Forms, Beth Carroll

Theses & ETDs

Locomotor behavior is a complex neural and musculoskeletal response to an animal's environment and other external factors. Morphology, behavior, and gait choice are closely interrelated and often coevolve in response to environmental change. Morphological, specifically osteological, correlates of specific behaviors and movement patterns observed in extant taxa provides insight into that of extinct groups in which fossilized bones and trackways provide the only clues. Extant taxa can be useful models for reconstructing the movements and behaviors of extinct forms. The mammalian ungulate clades seen today are a representation of a rich and diverse evolutionary history filled with multiple examples of …

Comparison Of Th1 Cytokines And T Cell Markers Gene Expressions Between Virulent And An Attenuated Eiav Vaccine Strain, Talia R. Henkle

Lewis Honors College Capstone Collection

The equine infectious anemia virus (EIAV) is closely related to HIV and has been used as a model to identify protective mechanisms against lentivirus infection. In horses, EIA infection progresses for about a year before infected horses manage to control virus replication. This naturally-gained protection is absolutely dependent on active immune responses as evidenced by the fact that immunosuppressive drugs can induce the recurrence of disease. As the resolution of initial viremia correlates with the appearance of virus specific cytotoxic T lymphocytes (CTL), we believe that cellular immune responses play a key role in controlling EIAV in the horse. In …

Intermittent Swim Stress Effects On Anxiety Behavior, Timothy A. Warner

Doctoral Dissertations

Millions of Americans are suffering from depression each year, leading to a significant number of individuals who seek treatment for their ailment. However, fewer than 50 percent of depressed individuals fully recover using current methods. The comorbidity between depression and anxiety could be a contributing factor in the lower rates of recovery. The demonstrated correlation between anxiety and depression has led to the term "anxious depression," which is associated with difficulty in coping, a poorer rate of recovery, and more severe symptoms of depression. The purpose of this dissertation was to expand on an existing animal model of depression (intermittent …

Interactions Of Shiga-Like Toxin-2 (Stx-2) From Escherichia Coli O157:H7 And The Bcl-2 Family Of Proteins During Host Cell Programmed Cell Death, Lia K. Jeffrey

Doctoral Dissertations

Stx-2 is a major contributor to the pathogenesis of Escherichia coli 0157:H7. Prior reports suggest that Stx-2 increases necrosis and apoptosis of a variety of host cells including those of endothelial origin as well as immune cells such as neutrophils (156). However, the role Stx-2 plays in delayed apoptosis of neutrophils is not fully understood given that previous studies have shown conflicting results (118, 51). The process of apoptosis is mediated by the Bcl-2 protein family (2, 46, 226). The purpose of this research was to define the molecular mechanisms of Stx-2 and Bcl-2 protein family interactions. These studies examined …

Engineering Lipases And Solvents For Trans/-Esterification Of Used Vegetable Oils, Michael Dore Gagnon

Doctoral Dissertations

Diminishing petroleum reserves and increasing environmental awareness has led to an urgent need to develop alternative fuels, such as biodiesel. However, the conventional method to produce biodiesel uses environmentally harmful chemical catalysts. A relatively new development in the production of biodiesel is through enzymatic trans/- esterification with a lipase catalyst. Despite several advantages, there are a few technical and economical obstacles that limit this process: (1) immiscibility of the hydrophilic methanol and hydrophobic triglyceride which results in the formation of an interface leading to mass transfer resistance, (2) insufficient availability of large quantities of inexpensive lipase suitable for catalysis, and …

Characterization Of The Expression Profile Of Polyamine Biosynthetic Genes (Spermidine Synthase) And Polyamine Metabolic Regulation In Arabidopsis, Lin Shao

Doctoral Dissertations

Polyamines are ubiquitously distributed cationic compounds, which play important roles in numerous cellular functions in plants. This study was aimed at elaborating the regulation of polyamine biosynthetic gene expression and polyamine metabolism. The organ/tissue specific expression patterns of two genes encoding the polyamine biosynthetic enzyme spermidine synthase ( AtSPDS1 and AtSPDS2) were studied in Arabidopsis at different developmental stages using promoter::reporter approach. The two homologues showed similar ubiquitous expression with subtle differences being observed in certain tissues (e.g. root, siliques, and embryos). Neither transgenic manipulation by over-expression of AtSPDSI alone nor its concomitant expression with genes encoding other biosynthetic enzymes …

Movements, Dive Behavior And Trophic Ecology Of Leatherback Turtles (Dermochelys Coriacea) In The Northwest Atlantic, Kara Dodge

Doctoral Dissertations

The endangered leatherback turtle is a highly migratory predator that feeds exclusively on gelatinous zooplankton. Leatherbacks spend most of their lives submerged or offshore, and their at-sea biology (particularly that of males and sub-adults) is poorly understood throughout much of their range. I used satellite telemetry to monitor movements and dive behavior of nine adult and eleven sub-adult leatherbacks captured off Massachusetts, USA, and tracked throughout the NW Atlantic. Leatherback movements and environmental associations varied by oceanographic region, with slow, sinuous, area-restricted search behavior and shorter, shallower dives occurring in cool, productive, shallow shelf habitat at temperate latitudes. Leatherbacks were …

Patterns Of Cytosine Methylation In The Genome Of Caenorhabditis Elegans, Kazufusa Okamoto

Doctoral Dissertations

Recent large-scale comparative analysis of cytosine DNA methylation across diverse eukaryotes suggest that early features of DNA methylation present in the last common ancestor of all eukaryotes some 1.6 to 1.8 billion years ago included the methylation of gene bodies and transposable elements (Zemach, McDaniel et al. 2010; Parfrey, Lahr et al. 2011). These potentially ancient patterns may reflect a primitive role of methylation in transcriptional fidelity and as a mechanism to protect the germ line from transposon, or repeat, mediated mutation. Because spurious transcription and mutation are hypothesized to be among the critical limiting factors to genome size, an …

The Effects Of Biotic And Abiotic Factors On Byssogenesis, Growth And Movement Patterns Of The Blue Mussel, Mytilus Edulis, Yvette Louise Garner

Doctoral Dissertations

Blue mussels create extensive aggregations on intertidal and low subtidal shores in the Gulf of Maine, in which they modify habitat, trap sediments and create microclimates for many organisms. Mussels are an important aquaculture species worldwide, and play a major part of the economy of New England. Blue mussels produce collagenous byssal threads to anchor themselves to the substrate on wave swept shores. Byssogenesis, growth and movement abilities of mussels are influenced by a host of biotic and abiotic factors. In this dissertation I quantified byssogenesis and growth of the blue mussel, Mytilus edulis, affected by wave exposure, temperature, and …

Regulation Of The Catalytic And Allosteric Properties Of Photoreceptor Phosphodiesterase (Pde6) By The Glutamic Acid-Rich Protein-2 (Garp2), Wei Yao

Doctoral Dissertations

The photoreceptor phosphodiesterase (PDE6) must be precisely regulated to control the sensitivity, amplitude, and kinetics of the photoresponse during excitation, termination and adaptation to light stimulation in rod and cone photoreceptors. The central hypothesis of this thesis is that one PDE6 binding partner, the glutamic acid-rich protein (GARP2), may regulate PDE6 to reduce its "dark noise", enhance its sensitivity and conserve metabolic energy during rod photoresponse saturation.

The first aim of this research is to better understand the unique biochemical and biophysical characteristics of GARP2 in order to reveal its functional attributes for regulating PDE6 during phototransduction in rod photoreceptors. …

Biology And Ecology Of Glyphosate-Resistant Giant Ragweed, Kabelo Segobye

Open Access Theses

Giant ragweed (Ambrosia trifida L.) is a competitive annual plant found in disturbed landscapes and is the most troublesome weed in Indiana and the US Corn Belt. It is one of the most common and problematic weeds in corn and soybean production. The introduction of herbicide glyphosate, N-(phosphonomethyl) glycine in early 1970's provided farmers with a better and low-cost tool to control weeds. The use of glyphosate drastically increased after the development of glyphosate resistant agronomic crops in 1996 and was use as a post-emergence selective herbicide. This led to overreliance and repeated use of glyphosate for weed control especially …

“Culling The Herd”: Eugenics And The Conservation Movement In The United States, 1900–1940, Garland E. Allen

Biology Faculty Research

While from a late twentieth- and early twenty-first century perspective, the ideologies of eugenics (controlled reproduction to eliminate the genetically unfit and promote the reproduction of the genetically fit) and environmental conservation and preservation, may seem incompatible, they were promoted simultaneously by a number of figures in the progressive era in the decades between 1900 and 1950. Common to the two movements were the desire to preserve the ‘‘best’’ in both the germ plasm of the human population and natural environments (including not only natural resources, but also undisturbed nature preserves such as state and national parks and forests). In …

A Bacterial Symbiont Is Converted From An Inedible Producer Of Beneficial Molecules Into Food By A Single Mutation In The Gaca Gene, Pierre Stallforth, Debra A. Brock, Alexandra M. Cantley, Xiangjun Tian, David C. Queller, Joan E. Strassmann, Jon Clardy

Biology Faculty Research

Stable multipartite mutualistic associations require that all partners benefit. We show that a single mutational step is sufficient to turn a symbiotic bacterium from an inedible but host-beneficial secondary metabolite producer into a host food source. The bacteria's host is a "farmer" clone of the social amoeba Dictyostelium discoideum that carries and disperses bacteria during its spore stage. Associated with the farmer are two strains of Pseudomonas fluorescens, only one of which serves as a food source. The other strain produces diffusible small molecules: pyrrolnitrin, a known antifungal agent, and a chromene that potently enhances the farmer's spore production and …

Evaluating The Impact Of Fishery-Related Claw Removal On Diet, Consumption Rate, Energetics And Reproduction In The Florida Stone Crab (Menippe Spp.), Jessica Mary Hogan

Theses and Dissertations

Many global fisheries are overexploited and working towards the development of sustainable fishing methods. Claw based crab fisheries, such as the Florida stone crab (Menippe mercenaria, M. adina, and hybrids) fishery, use unique fishing techniques that reduce the overall mortality of harvested organisms. For example, the Florida stone crab fishery is regulated by requiring that fisherman only harvest crab claws and requires that fishermen return the live crab to the water following harvesting. This process takes advantage of the ability of crabs to autotomize and regenerate their claws, and enables crabs to re-enter the fishery in subsequent years if they …

A New Social Gene In Dictyostelium Discoideum, Chtb, Lorenzo A. Santorelli, Adam Kuspa, Gad Shaulsky, David C. Queller, Joan E. Strassmann

Biology Faculty Research

BACKGROUND:

Competitive social interactions are ubiquitous in nature, but their genetic basis is difficult to determine. Much can be learned from single gene knockouts in a eukaryote microbe. The mutants can be competed with the parent to discern the social impact of that specific gene. Dictyostelium discoideum is a social amoeba that exhibits cooperative behavior in the construction of a multicellular fruiting body. It is a good model organism to study the genetic basis of cooperation since it has a sequenced genome and it is amenable to genetic manipulation. When two strains of D. discoideum are mixed, a cheater strain …