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Full-Text Articles in Cell and Developmental Biology

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil Dec 2023

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …


Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale Dec 2022

Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale

Electronic Theses and Dissertations

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic …


The Impacts Of Embryonic Arsenic Exposure Of Fundulus Heteroclitus, Torey Bowser Aug 2021

The Impacts Of Embryonic Arsenic Exposure Of Fundulus Heteroclitus, Torey Bowser

Electronic Theses and Dissertations

Arsenic is a toxic metalloid that exceeds safe drinking water standards in groundwater in many locations worldwide. Arsenic exposure in fish has been linked to destruction of gill tissues, impairment of growth, decreased muscle mass, memory impairment, increased aggression, and avoidance behaviors. We examined the behavior of mummichogs (Fundulus heteroclitus) following arsenic exposure during development in two studies. Embryos were collected from fish from three reference sites: Scorton Creek (SC), Massachusetts, Wells Harbor (WE), Maine, and Block Island (BLOC), Rhode Island and two contaminated sites: Callahan Mine (CM), Brooksville, Maine, and New Bedford Harbor (NBH), Massachusetts. Embryos were …


Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren Jan 2020

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren

Electronic Theses and Dissertations

Whereas a great deal has been learned about the molecular underpinnings of morphological evolution in animals, much less is known about the origin of novel cell and tissue types. During the time in which the earliest animal lineages were diversifying, fundamental cell and tissue types, such as muscles, arose. Sponges are one of two animal lineages that lack muscles, yet they undergo coordinated full body contractions. Whereas the signaling processes have been studied, the physical mechanisms of contraction are completely uncharacterized. The main purpose of this work is to understand the primary contractile tissue of the sponge Ephydatia muelleri, …


Origins Of Animal Cell Adhesion, Jennyfer Mora Mitchell Jan 2018

Origins Of Animal Cell Adhesion, Jennyfer Mora Mitchell

Electronic Theses and Dissertations

A fundamental requirement for multicellularity is cell adhesion. This includes mechanisms by which cells adhere to each other and to their secreted extracellular matrix (ECM). Two well characterized adhesion complexes in animals include: 1) adherens junctions (AJs), which are involved in cell-cell adhesion and composed of cadherin receptors, p120-, α- and β-catenin, and 2) focal adhesions (FAs), which are involved in cell-ECM adhesion and include proteins such as integrins, vinculin, paxillin, talin and focal adhesion kinase (FAK). The molecular components of AJs are widely conserved in animals, and largely absent in non-animals. In contrast, the molecular components of FAs have …


The Ecology And Evolution Of Rare, Soil Specialist Astragalus Plants In The Arid Western U.S., Joseph M. Statwick Jan 2016

The Ecology And Evolution Of Rare, Soil Specialist Astragalus Plants In The Arid Western U.S., Joseph M. Statwick

Electronic Theses and Dissertations

Organisms that specialize in uncommon habitats are, by their very nature, inherently uncommon. Specialization has its advantages, namely reduced competition and predation, but it also incurs costs. Specialists often have small population sizes, narrow ranges, and fragmented habitat, all of which engender negative consequences on an evolutionary timescale. Herein, I examine benefits and costs of specialization in selenium-hyperaccumulating plants in the genus Astragalus (Fabaceae). These plants are disproportionately likely to be rare and of conservation concern. Thus, I optimized germination pretreatments for Astragalus species such that seed loss can be minimized during ex situ cultivation, and found that physical scarification …


Tidal Influences On Bacterial And Phytoplankton Abundances And The Resulting Effects On Patterns Of Dissolved Oxygen In The Skidaway River Estuary, Casey Colleen Brazell Jan 2009

Tidal Influences On Bacterial And Phytoplankton Abundances And The Resulting Effects On Patterns Of Dissolved Oxygen In The Skidaway River Estuary, Casey Colleen Brazell

Electronic Theses and Dissertations

Two studies were conducted to investigate the physical and biological processes contributing to the dissolved oxygen (DO) availability in the Skidaway River Estuary (SRE), Savannah, GA during the summer of 2005. A temporal study looked at changes in DO concentrations, Chlorophyll a concentrations, bacterial abundance, water depth, and salinity, every hour, for 26 hours, over both a neap and a spring tide. A spatial study looked at changes in the above variables at 5 sites along the SRE while following the tide inland during a neap high and low tide, and a spring high and low tide. DO concentrations varied …