Life Sciences Commons^™

A Test Of The Hypothesis That Environmental Chemicals Interfere With Thyroid Hormone Action In Human Placenta, Katherine Geromini

Masters Theses 1911 - February 2014

Thyroid hormone is essential for normal brain development and recognition of this has led to universal screening of newborns for thyroid function to ensure that circulating levels of thyroid hormone are within a range known to be supportive of normal growth and mental development. Environmental chemicals that interfere with thyroid function are known to inhibit normal growth and mental development. Work from our lab and from labs internationally demonstrates in animal systems that some industrial chemicals such as PCBs, PBDEs, and others may interact with the thyroid hormone receptor(s) in ways that are not predicted by changes in serum thyroid …

An Investigation Of Human-Error Rates In Wildlife Photographic Identification; Implications For The Use Of Citizen Scientists, Megan Chesser

Masters Theses 1911 - February 2014

Rapid technological advancements in digital cameras and widespread public access to the internet have inspired many researchers to consider alternative methods for collecting, analyzing, and distributing scientific data. Two emerging fields of study that have capitalized on these developments are “citizen science” and photo-id in wildlife capture-mark-recapture (CMR) studies. Both approaches offer unprecedented flexibility and potential for acquiring previously inconceivable datasets, yet both remain dependent on data collection by human observers. The absence of rigorous assessment of observer error rates causes many scientists to resist citizen science altogether or to fail to incorporate citizen-collected data into ecological analyses. This same …

Investigating The Mechanism Of Nur77-Induced Apoptosis In T Cells, Heather E. Fogarty

Masters Theses 1911 - February 2014

Nur77 is a member of the orphan nuclear receptor family, where it is known to play an important role in apoptosis in both negative selection in T cells and in cancer cell lines. In the development of T cells, it is critical for the immune system to discriminate self from non-self by eliminating auto-reactive cells. It was originally thought that Nur77 initiated apoptosis by activating downstream gene targets. However, it is now clear that Nur77 has its own distinct role outside of the nucleus and the precise mechanisms by which Nur77 induces apoptosis in T cells still needs to be …

Population Size, Habitat Use And Diet Of Kittlitz's Murrelets In Prince William Sound, Alaska, Andrew J. Allyn

Masters Theses 1911 - February 2014

During the summer of 2008 and 2009, we studied the ecology of the Kittlitz’s Murrelet (Brachyramphus brevirostris), a small diving seabird and candidate for the U.S. Endangered Species List, in Prince William Sound (PWS), Alaska. At-sea survey data suggests that the population significantly increased from 2001 to 2009, however there is limited evidence of reproductive success. Habitat use models showed individuals were observed in shallower waters, closer to glaciers, the shoreline, and further from moraines than the available habitat during the daytime. Finer extent sampling from 2008 suggests temperature-depth profiles also influence Kittlitz’s Murrelet daytime habitat use. The …

The Effect Of Curcumin (Curcuma Longa) On Biofilm Formation And Surface Proteins Of Listeria Monocytogenes, Songsirin Ruengvisesh

Masters Theses 1911 - February 2014

The food-borne pathogen Listeria monocytogenes can attach to the environmental surfaces and develop biofilm which can cause food contamination in the food industries. Sortase A and surface proteins are involved in biofilm and virulence of L. monocytogenes. Curcumin was reported to inhibit sortase A and biofilm in gram positive bacteria. The overall objective of this study was to observe the effect of curcumin (Curcuma longa) on the biofilm formation and surface proteins of L. monocytogenes.

The antibiofilm effect of curcumin against the strain LM21 (wild type) and s22-11G (sortase A defective mutant) was studied using the …

Purification And Characterization Of Novel Nucleases From A Thermophilic Fungus, Kyle S. Landry

Masters Theses 1911 - February 2014

A thermophilic fungus was isolated from composted horse manure. The organism was as a Chaetomium sp. by sequencing the highly conserved ITS region of the fungus and comparing to known regions in a genomic database and was referred to as TM-417. TM-417 was found to have an optimal growth temperature of 45 ^oC and an optimal pH of 7.0. An extracellular DNase and RNase was found to be produced by the isolate and were purified 145.58-fold and 127.6-fold respectively using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined …

Semi-Active Damping For An Intelligent Adaptive Ankle Prosthesis, Andrew K. Lapre

Masters Theses 1911 - February 2014

Modern lower limb prostheses are devices that replace missing limbs, making it possible for lower limb amputees to walk again. Most commercially available prosthetic limbs lack intelligence and passive adaptive capabilities, and none available can adapt on a step by step basis. Often, amputees experience a loss of terrain adaptability as well as stability, leaving the amputee with a severely altered gait. This work is focused on the development of a semi-active damping system for use in intelligent terrain adaptive ankle prostheses. The system designed consists of an optimized hydraulic cylinder with an electronic servo valve which throttles the hydraulic …

Diving Behavior And Identification Of Sex Of Breeding Atlantic Puffins (Fratercula Arctica), And Nest-Site Characteristics Of Alcids On Petit Manan Island, Maine, Sarah M. Spencer

Masters Theses 1911 - February 2014

During 2008 – 2009, we quantified foraging behavior of adult Atlantic puffins (Fratercula arctica) by deploying time-depth recorders (TDRs) on 18 adults and collected morphological measurements from 40 adults nesting on Petit Manan Island, Maine. Dive data were successfully retrieved from 5 birds foraging for 14 days in 2008, and 8 birds foraging for 18 days in 2009. Pooling across all birds, a total of 8,097 dives were recorded, with peaks in activity during 0400-0800 and 1600-2000, and no diving between 2100 and 0400. Mean (± SD) dives/bird/day was 276.4 (± 84.7), with dives grouped into bouts lasting …

Impact Of Mental Toughness Training On Psychological And Physical Predictors Of Illness And Injury, Aisha Visram

Masters Theses 1911 - February 2014

Intense training for prolonged periods of time without adequate recovery can result in psychological problems and increased susceptibility to illness and injury in collegiate athletes. The Cognitive-Affective Model of Athletic Burnout (Smith, 1986), a framework for understanding the relationships among stressors, identifies cognitive appraisal as the mediating factor between negative or positive health outcomes, and therefore could be a target of interventions to reduce overtraining, burnout, injury, and illness. Mental toughness, the ability to perform at one’s best regardless of the circumstances, is a modifiable psychological construct that may influence cognitive appraisal. Altering an athlete’s interpretation of stressful situations through …

Investigation Of Compliance With The Ansi Z133.1 - 2006 Safety Standard In The New England Tree Care Industry, Alexandra K. Julius

Masters Theses 1911 - February 2014

Arborists are exposed to many occupational hazards and experience more than three times the overall fatality rate of all U.S. workers. Investigations into fatal incidents lead to a better understanding of industry dangers. However, this knowledge does not extend to how tree workers operate when an injury or fatality does not occur. Current research regarding fatal and nonfatal injuries does not include the accreditation status of the company at which the worker was employed, nor whether certified arborists were on staff. Given the highly skilled nature of the work involved, certification and accreditation might ensure a minimum level of demonstrated …

Population Dynamics, Chick Diet, And Foraging Behavior Of The Razorbill (Alca Torda) At Matinicus Rock, Maine, Katherine E. Kauffman

Masters Theses 1911 - February 2014

During the summers of 2007-2009, I studied the population growth and reproductive and foraging ecology of the Razorbill (Alca torda) at Matinicus Rock (MR), Maine. This medium-sized marine bird in the family Alcidae (auks) was extirpated from the Gulf of Maine in the late 19^th century by hunting, collecting, and colony disturbance. Following legislation protecting seabirds and their nesting habitats, the Razorbill has recolonized probable former nesting habitat in the Gulf of Maine during the past several decades. Six small colonies comprise the Maine population, which is listed as threatened and forms the southern extension of the …

Accessing The Bioavailability Of Phytochemicals In Caco-2 Cell Model And Developing A Sensitive Method For The Detection And Quantification Of These Compounds, Hana Shatara Sobers

Masters Theses 1911 - February 2014

Numerous studies have found certain unmethylated phytochemicals to possess anti-carcinogenic activity; however, they have been associated with poor oral bioavailability which is a major limiting factor in their usage in chemopreventative treatment. The purpose of this study was to investigate if methylation of a compound would affect bioavailability, in terms of transport and permeability, in a Caco-2 cell model as well as the effect of cell viability and cellular uptake in human colon cancer cell lines. Furthermore, a new analytic method using reversed-phase high performance liquid chromatography coupled with electrochemical detector (HPLC-EC) for the detection and quantification of resveratrol and …

Rhythmic Growth And Vascular Development In Brachypodium Distachyon, Dominick A. Matos

Masters Theses 1911 - February 2014

Plants reduce inorganic carbon to synthesize biomass that is comprised of mostly polysaccharides and lignin. Growth is intricately regulated by external cues such as light, temperature, and water availability and internal cues including those generated by the circadian clock. While many aspects of polymer biosynthesis are known, their regulation and distribution within the stem are poorly understood. Plant biomass is perhaps the most abundant organic substance on Earth and can be used as feedstock for energy production. Various grass species are under development as energy crops yet several of their attributes make them challenging research subjects. Brachypodium distachyon has emerged …

Notch Regulation Of Adam12 Expression In Glioblastoma Multiforme, Ala'a S. Alsyaideh

Masters Theses 1911 - February 2014

Glioblastoma is the most common malignant brain tumor, accounting for 17% of all primary brain tumors in the United States. Despite the available surgical, radiation, and chemical therapeutic options, the invasive and infiltrative nature of the tumor render current treatment options minimally effective. Recent reports have identified multiple regulators of glioblastoma progression and invasiveness. It has been demonstrated that ADAM12, A Disintegrin And Metalloproteinase encoded by ADAM12 gene, is over-expressed in glioblastoma and directly correlated with tumor proliferation. Additionally, dysregulation of the Notch signaling pathway has been implicated in the pathogenesis of many gliomas. Lastly, an evolving role of microRNAs, …

Prairie Warbler Nest-Site Selection, Nest Survival, And Demographic Response To Management In A Pitch Pine-Scrub Oak Barren, Michael E. Akresh

Masters Theses 1911 - February 2014

As shrubland bird populations decline, there is a critical need to understand the effects of habitat management. I studied a population of color-banded prairie warblers (Setophaga discolor) between 2008-2011 in a shifting mosaic landscape within a Massachusetts inland, pitch pine-scrub oak barren consisting of persistent, newly created, succeeding, and disturbed habitats. I present data showing that the abundance and population structure at this site appears to be a function of colonization of newly created habitat by second-year birds, which are likely excluded from mature early-successional habitat by site-faithful older birds. Breeding season fecundity did not differ significantly between …

Temperature Effects On Growth And Stress Physiology Of Brook Trout: Implications For Climate Change Impacts On An Iconic Cold-Water Fish, Joseph G. Chadwick Jr

Masters Theses 1911 - February 2014

Despite the threat of climate change, the physiological mechanisms by which temperature drives the distribution of species are unclear. Here we used chronic temperature exposures to determine that the upper limit for positive growth in the eastern brook trout (Salvelinus fontinalis) is 23.4 °C. Additionally, brook trout exposed to daily temperature oscillations of 8 °C, around a mean of 21 °C, exhibited growth rates that were 43 and 35% lower by length and weight respectively, than in constant 21 °C controls. Limitations in growth were associated with increases in indicators of the physiological stress response. Individuals exposed to …

Proteolytic Regulation Of Ctra, The Master Regulator Of Cell Cycle In Caulobacter Crescentus, Amber M. Cantin

Masters Theses 1911 - February 2014

Cell cycle progression in Caulobacter crescentus depends on the master regulator, CtrA. During the transition from swarmer to stalk cell (G1 to S phase), CtrA is degraded by the AAA+ protease ClpXP and levels rise again in the predivisional stage. The focus of this work is to explore how cyclic, regulated degradation is controlled. CtrA is known to bind to the origin of replication, thereby suppressing replication, so we first asked if DNA binding had an effect on CtrA stability. CtrA is readily degraded by ClpXP on its own, but when bound to DNA containing the proper binding sites, degradation …

Investigation Of Differential Vector Competence Of Bartonella Quintana In Human Head And Body Lice, Domenic J. Previte

Masters Theses 1911 - February 2014

Human head and body lice are obligatory hematophagous ectoparasites that belong to a single species Pediculus humanus. Only body lice, however, are vectors of the infections gram-negative bacteria Bartonella quintana. Due to their near identical genomes, yet differential vector competency, head and body lice provide an ideal model system to study an insects ability to gain or lose vector competency. Using our in vitro louse rearing system, we have infected both head and body lice with a blood containing B. quintana in order to detect differences in B. quintana proliferation between head and body lice as well as …

Providing Further Construct Validity For A Newly Developed Functional-Living Measure: The Movement And Activity In Physical Space (Maps) Score, Andrea M. Morand

Masters Theses 1911 - February 2014

Older adults face many age-related changes affecting functional ability. Function is defined as the interaction between a person and their real-world environment. Currently, no objective measures of function exist assessing the environmental component. A newly-developed measure of functional-living, the Movement and Activity in Physical Space (MAPS) score, combines accelerometer and geospatial data providing quantitative measurement of real-world function. Because MAPS is a new measure of functional-living, the purpose of the current study was to provide further construct validity for MAPS as a functional-living measure in older adults and to determine what combination of 3 days, using weekend and week days, …

Development Of A Cytosolic Ph Reporter For Tobacco By2 Cells, Michael E. Urbanowski

Masters Theses 1911 - February 2014

The regulation of pH is a critical homeostatic function of plant cells. In addition to acting as the primary cationic species responsible for energizing the plasma membrane, protons likely act as an important regulator and messenger. Despite this importance, few studies have thoroughly described cytosolic pH patterns as the plant cell progresses through the cell cycle. To investigate pH in plant cells, I chose Nicotiana tabacum (tobacco) Bright Yellow-2 (BY-2) cells as a model system. My research has two aims. First, I will measure and report the interphase cytosolic pH of BY-2 cells. Next, I will assay the cytosolic pH …