Biology Commons^™

Bite Force And Stress Content Of Varying Tooth Morphology And Jaw Alignment, Emily Newenhisen

Williams Honors College, Honors Research Projects

Biting is one of the primary physical actions against a food substrate involved in the process of mastication and consumption. Different shapes of solidified tissue (e.g., teeth, mandibles) are developed based on dietary preferences of the organism to improve mechanical function. Models of various geometric shapes were used to loosely replicate several common biological tooth structures. As there is little research conducted on tooth penetration force in relation to tooth shape, collection of such data was the main focus of the research. Molariform teeth found in herbivores were represented by the ball model, carnivorous needle-like teeth by cone model, cutting …

Novel Mechanistic Insight Into Ciliary Regulation: Old Pathways Yield New Mechanisms, Larissa L. Dougherty

Dartmouth College Ph.D Dissertations

Cilia are structures present on most eukaryotic cells which provide important signaling and motile components to cells from early development to fully differentiated and matured cells. Regulation of these structures is critical to proper functioning of the cell and is known to be tied to the cell cycle. Preparation for ciliary assembly following cell cycle exit and ciliary disassembly following cell cycle reentry requires components throughout the cell body and within the cilium to facilitate this process. Here I identify how the cell adapts to ensure modifications to cilia occur for assembly or disassembly using the model organism Chlamydomonas reinhardtii. …

A Fecal Survey To Evaluate The Prevalence Of Enteric Viruses In Laboratory Mice, Amina Khatun

Browse all Theses and Dissertations

The study was conducted to investigate the prevalence of four enteric viruses in mouse research facilities that may not be captured by routine pathogen screening. Fecal samples were collected from contact-sentinel mouse cages between April 2022 and January 2023, and screened for the presence of viral genome by RT-qPCR. Out of a total of 50 samples, murine norovirus and murine astrovirus were detected in two (4%) and one (2%) sample, respectively, while murine adenovirus and murine rotavirus were not detected. Furthermore, all samples were screened for the presence of infectious murine noroviruses and astroviruses using the RAW264.7 and Vero cells …

Deciphering The Pathway Of Human Astrovirus Release From Infected Cells, Joshua Eduful

Browse all Theses and Dissertations

During infection, viruses are released from infected cells and spread to neighboring cells either through a lytic pathway (by rupturing cells), a non-lytic pathway (such as the use of extracellular vesicles), or both pathways. Human astroviruses (HAstV) are highly prevalent non-enveloped positive sense RNA viruses. They are separated into three clades, classic-type, MLB-type and VA-type, in humans. They are identified as the third leading cause of viral gastroenteritis in children, the elderly, and immunocompromised patients. Yet, little is known about the replication, transmission, immunity, and epidemiology of these viruses. Thus, I sought to investigate the possible pathways HAstV utilize to …

Characterization Of The Roles Of Mitochondria In The Toxicity Of Α-Synuclein In A Respiratory Cell Model, Breonna Elizabeth Gillespie

Browse all Theses and Dissertations

Although α-synuclein (α-syn) has been linked genetically and pathologically to Parkinson’s disease, the mechanism by which it drives disease pathogenesis is not fully understood. When α-syn is overexpressed in yeast, it forms abnormal cytoplasmic accumulations and leads to cell death, resembling the phenotypes observed in neurons. Such yeast models have been widely used to uncover molecular mechanisms of α-syn toxicity, but the induction of α-syn relies on growing yeast in galactose, a fermentable carbon source. Yeast does not require cellular respiration when grown in galactose, thus limiting the understanding of α-syn toxicity when cellular respiration is essential for neurons. We …

Editorial: Morphoevodevo: A Multilevel Approach To Elucidate The Evolution Of Metazoan Organ Systems, Andreas Wanninger, Pedro Martinez, Néva P. Meyer

Biology

Editorial on the Research Topic MorphoEvoDevo: a multilevel approach to elucidate the evolution of metazoan organ systems.

Investigating The Role Of Lim Kinase In Embryonic Development, Nehul Dharmesh Tanna

Senior Honors Theses and Projects

Cellular communication is important in embryonic development. It facilitates timely migration and maturation of cells to produce a fully functional organism using cell signaling pathways. These pathways involve receptors, ligands, and intracellular enzymes to produce different effects in the cell. One such pathway, the EphA4 signaling pathway, is involved in altering the cytoskeleton of eukaryotic cells. LIM kinases (LIMKs) are enzymes that regulate important components of the cytoskeleton. We hypothesized involvement of LIMKs in the EphA4 pathway and investigated their involvement in X. laevis embryonic development as a first step toward evaluating this hypothesis. We mutated LIMK genes in frog …

Land Systems, Soils And Vegetation Of The Southern Goldfields And Great Western Woodlands Of Western Australia - Volume 1, Peter-Jon A. Waddell, Paul Galloway

Technical Bulletins

This technical bulletin defines and maps the land resources of the southern Goldfields region of Western Australia (WA). The southern Goldfields region, as featured in this bulletin, covers 151,753 km². The western and eastern borders are variable because they align with various cadastral boundaries. The western survey border, which in part follows the WA State Barrier Fence, demarcates cleared agricultural land from the intact, western extent of the Great Western Woodlands. The eastern border abuts the westernmost Nullarbor pastoral lease boundaries, except for the north-easternmost and south-easternmost edges which continue into Crown land. Major towns are Coolgardie, Kalgoorlie …

Land Systems, Soils And Vegetation Of The Southern Goldfields And Great Western Woodlands Of Western Australia - Volume 2, Peter-Jon A. Waddell, Paul Galloway

Technical Bulletins

This technical bulletin defines and maps the land resources of the southern Goldfields region of Western Australia (WA). The southern Goldfields region, as featured in this bulletin, covers 151,753 km². The western and eastern borders are variable because they align with various cadastral boundaries. The western survey border, which in part follows the WA State Barrier Fence, demarcates cleared agricultural land from the intact, western extent of the Great Western Woodlands. The eastern border abuts the westernmost Nullarbor pastoral lease boundaries, except for the north-easternmost and south-easternmost edges which continue into Crown land. Major towns are Coolgardie, Kalgoorlie …

Examining The Effects Of Hyperglycemia On Retinal Regeneration, Emmanuella Ec Kyllians

Theses and Dissertations--Biology

Diabetes is a disease that affects how the body processes glucose, leading to a cascade of other complications, one of which is diabetic retinopathy (DR). DR is a neurovascular disease that affects the retina and research has revealed the role of retinal neurodegeneration in its development. Animal models like zebrafish have emerged as important tools for studying the molecular and cellular mechanisms underlying DR. On the other hand, retinitis pigmentosa (RP) is a degenerative disease that involves the progressive degeneration of rods and cones, and hyperglycemia has been found to impair regeneration. Therefore, this study aims to examine the effects …

Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Terrestrial plant communities are shaped by competition for resources, herbivory, and abiotic processes. Savanna systems represent a dynamic coexistence of contrasting life forms (grasses and trees) shaped by competition and disturbance. The Kentucky Inner Bluegrass Savanna-Woodland (KIBSW) is described as an open woodland of shade intolerant species; however, climatic, and edaphic conditions can support closed-canopy forest. After European pioneer settlement (c1750-1800), over 99% of “savanna-woodlands” have been lost. KIBSW remnants are experiencing a recruitment failure, leading to a dominance shift in tree communities. I researched how tree-grass competition and mammalian herbivory influence KIBSW regeneration and maintenance. The KIBSW does not …

Parental Effects On Offspring Reaction Norms: Consequences For Complex Phenotypes In Variable Environments, Alexandra G. Cones

Theses and Dissertations--Biology

Organismal traits all exhibit some degree of environmental sensitivity, and both the strength and direction of these phenotypically plastic responses to the environment can evolve in adaptive ways. For example, parents can use information about their own environment to precondition the traits of their offspring so that they thrive in their future environment. This transgenerational plasticity can also alter the plasticity of offspring, but explicit investigations of this specific phenomenon are rare. I begin with a review of the literature and provide a quantitative genetic framework to investigate this phenomenon, which I then explore empirically using avian embryos. The metabolic …

Multilevel Phenotypic Integration Of Metabolism And Behavior In House Sparrows And Mice, Tim Salzman

Theses and Dissertations--Biology

Patterns of multilevel variation in behavior, both within and among individuals, raise challenging questions about underlying mechanisms and the selective pressures acting on them. One intriguing hypothesis is that physiology shows parallel multilevel variation, and so might represent a latent trait that integrates multilevel behavioral responses. For example, foraging acquires the fuel needed to maintain metabolism, and in turn, an individual’s metabolism affects expression of foraging, and other, behaviors. Metabolism and behavior thus might coevolve to become integrated traits. Despite the appeal of this hypothesis, numerous investigations into the link between metabolism and behavior have yielded largely equivocal results.

To …

Intercontinental Comparisons Of Subterranean Host-Parasite Communities Using Bipartite Network Analyses, Altangerel Tsogtsaikhan Dursahinhan, Sebastian Botero-Cañola, Scott L. Gardner

Scott L. Gardner Publications

Rodents living in a subterranean ecotope face a unique combination of evolutionary and ecological pressures and while host species evolution may be driven by the selective pressure from the parasites they harbour, the parasites may be responding to the selective pressures of the host. Here we obtained all available subterranean rodent host-parasite records from the literature and integrated these data by utilizing a bipartite network analysis to determine multiple critical parameters to quantify and measure the structure and interactions of the organisms present in host-parasite communities. A total of 163 species of subterranean rodent hosts, 174 parasite species, and 282 …

Stochasticity Directs Adaptive Evolution Toward Nonequilibrium Evolutionary Attractors, John Delong, Clayton E. Cressler

School of Biological Sciences: Faculty Publications

Stochastic processes such as genetic drift may hinder adaptation, but the effect of such stochasticity on evolution via its effect on ecological dynamics is poorly understood. Here we evaluate patterns of adaptation in a population subject to variation in demographic stochasticity. We show that stochasticity can alter population dynamics and lead to evolutionary outcomes that are not predicted by classic eco-evolutionary modeling approaches. We also show, however, that these outcomes are governed by nonequilibrium evolutionary attractors— these are maxima in lifetime reproductive success when stochasticity keeps the ecological system away from the deterministic equilibrium. These NEEAs alter the path of …

The Consumption Of Viruses Returns Energy To Food Chains, John Delong, James L. Van Etten, Zeina Al-Ameeli, Irina Agarkova, David Dunigan

School of Biological Sciences: Faculty Publications

Viruses impact host cells and have indirect effects on ecosystem processes. Plankton such as ciliates can reduce the abundance of virions in water, but whether virus consumption translates into demographic consequences for the grazers is unknown. Here, we show that small protists not only can consume viruses they also can grow and divide given only viruses to eat. Moreover, the ciliate Halteria sp. foraging on chloroviruses displays dynamics and interaction parameters that are similar to other microbial trophic interactions. These results suggest that the effect of viruses on ecosystems extends beyond (and in contrast to) the viral shunt by redirecting …

Pathways Of Density Dependence And Natural Selection In Modern Humans, John Delong

School of Biological Sciences: Faculty Publications

Living things depend on a flow of energy and materials to grow, reproduce, and maintain their bodies. Populations are aggregations of individuals, so they too depend on resources. Humans use many fuels derived from the Earth’s photosynthetic energy, which in turn support a population that often occurs at unusually high densities for a mammal. Like most populations, growing human populations may experience negative feedbacks from population size unless the socio-economic system in which the population lives grows fast enough to maintain resource flows to individuals and to limit the downsides of high density. I map out a simple view of …

Investigating The Effects Of Disturbance And Competition On Establishment, Growth, And Reproduction Of The Endangered Ripariosida Hermaphrodita, Daniel Engelking

Theses and Dissertations (Comprehensive)

Ripariosida hermaphrodita (Virginia Mallow) is a perennial riparian plant with broad, maple-like leaves. It grows up to three meters high and is often found in large clonal patches, but sexually reproduces readily. While this plant may seem like a redoubtable competitor when growing in large colonies, it is declining across its range in North America. The only known occurrences in Canada are in southern Ontario. Prior to this study, no new populations had been recorded even though one of the known populations produces copious amounts of viable seed with potential to disperse. There are many hypotheses for its rarity, but …

Differences In Drifting Invertebrate Communities Across Arctic Ecozones And The Influence On Potential Growth Of Grayling (Thymallus Arcticus), Charles Chanyi

Theses and Dissertations (Comprehensive)

Invertebrate drift is a key process that potentially affects multiple levels of food web organization within stream environments. However, our understanding of the mechanistic drivers of drift in high latitude streams and subsequent bottom-up control that drift may have on fish predators in these environments remains understudied. This project aimed to gain the baseline knowledge of how drift functions across two major high latitude ecozones, the boreal forest and tundra, and how those possible differences in drifting community characteristics may impact drift-feeding Arctic grayling (Thymallus arcticus). These objectives were accomplished by characterizing stream environments across both ecozones, sampling …

Temperature Regulation Of Plant- Rhizobacteria Interactions Within The Soil-Rhizosphere- Rhizoplane Interface, Eric J. R. Marchetta

Theses and Dissertations (Comprehensive)

An optimal microbiome is important for plant health and can prime subsequent plant immune responses to enhance stress resilience. However, the molecular mechanisms that dynamically drive host-microbiome interactions and subsequent induced systemic resistance (ISR) responses in plants under elevated environmental temperatures remain underexplored. To address this major knowledge gap, this thesis further investigated Canadian soil-inhabiting rhizobacteria that had been previously shown to activate ISR in tomato (Solanum lycopersicum) plants. Specifically, this study characterized the in vitro physiology of these rhizobacterial strains under different temperatures, including growth, phosphate solubilization abilities and direct anti- pathogenic capabilities. Temperature-sensitivity of these parameters …

Natural Variation In Temperature-Modulated Immunity To Pseudomonas Syringae Pv. Tomato (Pst Dc3000) In Arabidopsis Thaliana Plants, Christina A. M. Rossi

Theses and Dissertations (Comprehensive)

Studies conducted on the model plant-pathogen system Arabidopsis thaliana-Pseudomonas syringae pv. tomato (Pst) showed that elevated temperature suppresses the pathogen-induced production of salicylic acid (SA), which is a key plant defence hormone. This increased host vulnerability at higher temperatures is due to downregulated expression of CALMODULIN BINDING PROTEIN 60-LIKE G (CBP60g) and SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1), which encode master regulators of SA production. Collectively, these previous studies only focused on one natural accession of Arabidopsis called Columbia-0 (Col-0). However, the intraspecific variation in Arabidopsis immunity phenotypes under elevated temperature remains unknown. To fill this critical knowledge gap, my …

Blue Carbon Science, Management And Policy Across A Tropical Urban Landscape, Daniel A. Friess, Yasmine M. Gatt, Tze Kwan Fung, Jahson B. Alemu I, Natasha Bhatia, Rebecca Case, Siew Chin Chua, Danwei Huang, Valerie Kwan, Kiah Eng Lim, Yudhishthra Nathan, Yan Xiang Ow, Daniel Saavedra-Hortua, Taylor M. Sloey, Erik S. Yando, Hassan Ibrahim, Lian Pin Koh, Jun Yu Puah, Serena Lay-Ming Teo, Karenne Tun, Lynn Wei Wong, Siti Maryam Yaakub

Biological Sciences Faculty Publications

The ability of vegetated coastal ecosystems to sequester high rates of “blue” carbon over millennial time scales has attracted the interest of national and international policy makers as a tool for climate change mitigation. Whereas focus on blue carbon conservation has been mostly on threatened rural seascapes, there is scope to consider blue carbon dynamics along highly fragmented and developed urban coastlines. The tropical city state of Singapore is used as a case study of urban blue carbon knowledge generation, how blue carbon changes over time with urban development, and how such knowledge can be integrated into urban planning alongside …

Promiscuous Feeding Across Multiple Honey Bee Hosts Amplifies The Vectorial Capacity Of Varroa Destructor, Zachary S. Lamas, Serhat Solmaz, Eugene V. Ryabov, Joseph Mowery, Matthew Heermann, Daniel Sonenshine, Jay D. Evans, David J. Hawthorne

Biological Sciences Faculty Publications

Varroa destructor is a cosmopolitan pest and leading cause of colony loss of the European honey bee. Historically described as a competent vector of honey bee viruses, this arthropod vector is the cause of a global pandemic of Deformed wing virus, now endemic in honeybee populations in all Varroa-infested regions. Our work shows that viral spread is driven by Varroa actively switching from one adult bee to another as they feed. Assays using fluorescent microspheres were used to indicate the movement of fluids in both directions between host and vector when Varroa feed. Therefore, Varroa could be in either …

Strong, Recent Selective Sweeps Reshape Genetic Diversity In Freshwater Bivalve Megalonaias Nervosa, Rebekah L. Rogers, Stephanie L. Grizzard, Jeffrey T. Garner

Biological Sciences Faculty Publications

Freshwater Unionid bivalves have recently faced ecological upheaval through pollution, barriers to dispersal, harvesting, and changes in fish–host prevalence. Currently, over 70% of species in North America are threatened, endangered or extinct. To characterize the genetic response to recent selective pressures, we collected population genetic data for one successful bivalve species, Megalonaias nervosa. We identify megabase-sized regions that are nearly monomorphic across the population, signals of strong, recent selection reshaping diversity across 73 Mb total. These signatures of selection are greater than is commonly seen in population genetic models. We observe 102 duplicate genes with high dN/d …

The Practice And Promise Of Temporal Genomics For Measuring Evolutionary Responses To Global Change, René D. Clark, Katrina A. Catalano, Kyra S. Fitz, Eric Garcia, Kyle E. Jaynes, Brendan N. Reid, Allyson Sawkins, Anthony A. Snead, John C. Whalen, Malin L. Pinsky

Biological Sciences Faculty Publications

Understanding the evolutionary consequences of anthropogenic change is imperative for estimating long-term species resilience. While contemporary genomic data can provide us with important insights into recent demographic histories, investigating past change using present genomic data alone has limitations. In comparison, temporal genomics studies, defined herein as those that incorporate time series genomic data, utilize museum collections and repeated field sampling to directly examine evolutionary change. As temporal genomics is applied to more systems, species and questions, best practices can be helpful guides to make the most efficient use of limited resources. Here, we conduct a systematic literature review to synthesize …

The Coral Bleaching Automated Stress System (Cbass): A Low-Cost, Portable System For Standardized Empirical Assessments Of Coral Thermal Limits, Nicholas R. Evensen, Katherine E. Parker, Thomas A. Oliver, Stephen R. Palumbi, Cheryl A. Logan, James S. Ryan, Courtney N. Klepac, Gabriela Perna, Mark E. Warner, Christian R. Voolstra, Daniel J. Barshis

Biological Sciences Faculty Publications

Ocean warming is increasingly affecting marine ecosystems across the globe. Reef-building corals are particularly affected by warming, with mass bleaching events increasing in frequency and leading to widespread coral mortality. Yet, some corals can resist or recover from bleaching better than others. Such variability in thermal resilience could be critical to reef persistence; however, the scientific community lacks standardized diagnostic approaches to rapidly and comparatively assess coral thermal vulnerability prior to bleaching events. We present the Coral Bleaching Automated Stress System (CBASS) as a low-cost, open-source, field-portable experimental system for rapid empirical assessment of coral thermal thresholds using standardized temperature …

Use Of Amino Acid Isotope Analysis To Investigate Capital Versus Income Breeding Strategies In Migratory Avian Species, Nico Lübcker, John P. Whiteman, Oliver N. Shipley, Keith A. Hobson, Seth D. Newsome

Biological Sciences Faculty Publications

1. Income and capital breeding represent opposing ends of a continuum of reproductive strategies. Quantifying nutrient allocation to reproduction is challenging, but recent advances in compound-specific stable isotope analysis hold promise for tracing the source of individual compounds allocated to reproduction.

2. Here, we describe a novel approach of using measured carbon (δ13C) and nitrogen (δ15N) isotope values of individual amino acids (AAs) in pectoral muscle of egg-laying females and egg yolk as a useful tool to quantify the reliance on income versus capital breeding in migrating species. We used white-fronted (Anser albifrons frontalis), lesser snow (A. …

Co-Occurrence Of Marine And Freshwater Phycotoxins In Oysters, And Analysis Of Possible Predictors For Management, Sarah K. D. Pease, Todd A. Egerton, Kimberly S. Reece, Marta P. Sanderson, Michelle D. Onofrio, Evan Yeargan, Adam Wood, Amanda Roach, I-Shuo Wade Huang, Gail P. Scott, Allen R. Place, Amy M. Hayes, Juliette L. Smith

Biological Sciences Faculty Publications

Oysters (Crassostrea virginica) were screened for 12 phycotoxins over two years in nearshore waters to collect baseline phycotoxin data and to determine prevalence of phycotoxin co-occurrence in the commercially and ecologically-relevant species. Trace to low concentrations of azaspiracid-1 and -2 (AZA1, AZA2), domoic acid (DA), okadaic acid (OA), and dinophysistoxin-1 (DTX1) were detected, orders of magnitude below seafood safety action levels. Microcystins (MCs), MC-RR and MC-YR, were also found in oysters (maximum: 7.12 μg MC-RR/kg shellfish meat wet weight), warranting consideration of developing action levels for freshwater phycotoxins in marine shellfish. Oysters contained phycotoxins that impair shellfish health: karlotoxin1-1 and …

Frankenbacteriosis Targeting Interactions Between Pathogen And Symbiont To Control Infection In The Tick Vector, Lorena Mazuecos, Pilar Alberdi, Angélica Hernández-Jarguín, Marinela Contreras, Margarita Villar, Alejandro Cabezas-Cruz, Ladislav Simo, Almudena González-García, Sandra Díaz-Sánchez, Girish Neelakanta, Sarah I. Bonnet, Erol Fikrig, José De La Fuente

Biological Sciences Faculty Publications

(Summary) Tick microbiota can be targeted for the control of tick-borne diseases such as human granulocytic anaplasmosis (HGA) caused by model pathogen, Anaplasma phagocytophilum. Frankenbacteriosis is inspired by Frankenstein and defined here as paratransgenesis of tick symbiotic/commensal bacteria to mimic and compete with tick-borne pathogens. Interactions between A. phagocytophilum and symbiotic Sphingomonas identified by metaproteomics analysis in Ixodes scapularis midgut showed competition between both bacteria. Consequently, Sphingomonas was selected for frankenbacteriosis for the control of A. phagocytophilum infection and transmission. The results showed that Franken Sphingomonas producing A. phagocytophilum major surface protein 4 (MSP4) mimic pathogen and reduce infection …

Multiple Interacting Stressors Influence Development, Growth, And Morphology Of Pacific Chorus Frog (Pseudacris Regilla) Larvae, Abby Dalke, Allie M. Erickson, Bailey R. Tasker, Skylar Riley, Paul Hurst, Sarah Cooney, Scott A. Griffith, Betsy A. Bancroft

Biology Faculty Scholarship

Freshwater ecosystems are threatened by climate change and invasive species. Amphibians are important members of freshwater communities and are susceptible to negative effects of climate change and invasion. Furthermore, both climate change and invasion can influence density of amphibian larvae at the microhabitat scale because of larval clustering. To understand the effects of climate change and invasion on Pacific Chorus Frog Pseudacris regilla (Baird and Girard, 1852) larvae, a 2 × 2 × 2 factorial experiment was carried out with a climate treatment (future/historical; simulated as changes in both temperature and hydroperiod), indirect exposure to the invasive Brook Stickleback Culaea …