Life Sciences Commons^™

Fern Community Reassembly In Secondary Forests Of Puerto Rico: Predictors, Complexity, And Niche Model Assessment, Thomas J. Schmidt

Masters Theses

Approximately 94% of Puerto Rico’s forests were converted into agricultural systems by 1950. Since then, extensive abandonment of agricultural land has resulted in a considerable amount of forest regeneration throughout the main island. Ferns are a major non-woody component of oceanic, tropical island forests comprising up to seventy percent of the flora. Consequently, the composition and community structure of ferns may be indicative of the relative richness of these secondary forests. I used Maximum Entropy (Maxent), a widely-used mathematical tool for distinguishing suitable versus unsuitable fern niche space, along with ENMTools, a tool that assists Maxent with proper model selection, …

Genetic Structure Of Yellow Perch Populations In Coastal Areas Of Eastern Lake Michigan, Jessica N. Wesolek

Masters Theses

Genetic population substructure is often overlooked because of discontinuities between management and actual population structure as in the case of yellow perch, an ecologically and economically important indigenous fish species in the Laurentian Great Lakes. A knowledge gaps pertaining to the natural history of yellow perch relates to the biological connectivity between nearshore Lake Michigan and drowned river mouth (DRM) lakes, where it remains unclear whether resident yellow perch from Lake Michigan use DRM lakes for spawning or whether DRM lakes contribute to nearshore yellow perch populations in Lake Michigan. I used DNA fingerprinting (genotyping) to explore biological connectivity between …

Structural Comparison Of Arctic Plant Communities Across The Landscape And With Experimental Warming In Northern Alaska, Jessica L. Gregory

Masters Theses

Understanding vegetation change is central to forecasting the impacts of climate change. Percent cover, determined from a point frame method, is commonly used to monitor vegetation change. Cover is influenced by canopy structure which may change with the size (growth) or number (density) of individual plants. The overarching objective of this project was to document the relationship between vegetation cover and traits representing plant growth and density and determine if these relationships changed with warming. We used regressions and analysis of covariance to detect which of several traits was most strongly related to cover in vegetation at a wet and …

Characterization Of Histidine Decarboxylase In Drosophila Using An Internal Flag Epitope, Maxwell Mianecki

Masters Theses

Histamine is a neurotransmitter in arthropods and is responsible for synaptic transmission in vision, mechanosensation, temperature sensing and sleep cycle in Drosophila. Histamine is synthesized by the enzyme histidine decarboxylase (HDC). While histamine is detectable within tissues using current immunofluorescent labeling techniques, immunological approaches have not been successful for HDC itself, with both direct antibodies and terminal epitope tags determined to be ineffective. In order to avoid loss of the epitope tag through putative N-­‐ and C-­‐terminal proteolytic cleavage, known to occur for HDC in other organisms, an internal epitope tag that does not disrupt enzyme function was utilized. A …

Evaluation Of Natural Steelhead Recruitment In The Muskegon River, Michigan, Nicholas C. Albrecht

Masters Theses

The lower Muskegon River is one of the most heavily fished rivers in the state of Michigan and is a valuable component of the multi-billion dollar sport fishery in the Great Lakes. Although significant stocking effort has been invested to maintain and improve the steelhead (Oncorhynchus mykiss) fishery in the Muskegon River, natural recruitment has been severely limited due to high summer water temperatures. The goal of this research project was to evaluate the success of a diffuser system installed in 2008 at Croton Dam to moderate high summer water temperatures in the lower Muskegon River. I estimated natural juvenile …

Genetic Health And Population Viability Of Reintroduced American Marten In Michigan, Tamara L. Hillman

Masters Theses

American marten (Martes americana) were extirpated from Michigan’s Lower Peninsula (LP) in 1911, and subsequently from the Upper Peninsula (UP) in 1939 due to habitat loss and unregulated trapping. The species was later reintroduced in the UP in the mid-1950s, and to the LP in the mid-1980s. Previous research has determined the small founding sizes used in the LP reintroductions have resulted in losses of genetic diversity, while research in the UP has produced discordant results concerning the effects of the reintroduction methods on genetic health and population structure. Since past research of marten in the LP, no …

Predictive Modeling Of Floral Species Richness In Michigan Prairie Fen Communities, Nichole R. Mason

Masters Theses

Prairie fens contain high levels of floral biodiversity, including 19 state threatened or endangered plant species, and are classified as rare and vulnerable communities by the Michigan Natural Features Inventory. The objective of this thesis was to develop multiple-regression (MR) models that reliably predict total, native, and invasive floral species richness for use by conservation organizations. Floral biodiversity surveys were conducted in eight southern Michigan prairie fens during the 2012 growing season. Simple linear regressions between fen size and biodiversity were used to optimize sampling strategy and effort (i.e., number of transects and plots per transect) in surveys conducted in …

Localization Of Chemoreceptors In Azospirillum Brasilense., Anastasia Aksenova

Masters Theses

In order to ensure their survival, bacteria must sense and adapt to a variety of environmental signals. Motile bacteria are able to orient their movement in a chemical gradient by chemotaxis. During chemotaxis, environmental signals are detected by chemotaxis receptors and are propagated via a signal transduction cascade to affect bacterial motility. In a model organism Escherichia coli, chemotaxis receptors, also called MCPs (for methyl-accepting chemotaxis proteins) sense changes in concentration gradients by making temporal comparisons about the chemical composition of their surroundings. Decreased attractant concentration or increased repellant concentration results in conformational changes in the MCPs that culminate …

Performance Of Beef Cattle Grazing Native Warm-Season Grasses In An Integrated Forage/Biofuels System In The Mid-South, William Matthew Backus

Masters Theses

Early season (ES) and full season (FS) grazing strategies were used to evaluate performance of stocker steers grazing native warm-season grasses (NWSG) in 2010, 2011 and 2012 in two experiments. Experiment one was conducted at the Research and Education Center (REC) at Ames Plantation near Grand Junction and experiment two was conducted at Highland Rim REC near Springfield in which Angus and Angus cross steers (268±25kg) were used in completely randomized design with three forage treatments: 1) switchgrass (Panicum virgatum L.); 2) a combination of big bluestem (Andropogon gerardii Vitman) and indiangrass (Sorghastrum nutans); and 3) …

The Seasonality Of Two Parasitoids (Spathius Agrili And Tetrastichus Planipennisi) Of The Emerald Ash Borer, Agrilus Planipennis, And A Survey For Native Natural Enemies Of The Emerald Ash Borer In Eastern Tennessee, Nicholas Andrew Hooie

Masters Theses

The emerald ash borer (EAB), Agrilus planipennisi Fairmaire (Coleoptera: Buprestidae), is an invasive species of bark borer native to eastern Asia whose primary habitat and food sources are trees in the genus Fraxinus. EAB is a major pest of all North American Fraxinus species and is responsible for mortality of millions of trees across its current North American range of 23 U.S states and 2 Canadian providences. After the discovery of EAB in Tennessee in 2010, parasitoid releases were started under the national EAB Biological Control Program. A research project was initiated in 2012 to 1) study the seasonality …

Control Of Emerging Foodborne Viruses Using Cranberry Extracts And Chemical Sanitizers, Snigdha Nitin Sewlikar

Masters Theses

Human norovirus (HNoV), hepatitis A virus (HAV) and Aichi virus (AiV) outbreaks that cause severe foodborne disease are on the rise globally. Strategies to prevent and mitigate the spread of these viral infections need to be investigated. HNoV, HAV and AiV are known to be resistant to most of the conventionally used chemical inactivation methods. Cranberry juice (CJ) and cranberry proanthocyanidins (C-PAC) have demonstrated antimicrobial and anti-inflammatory properties. CJ and C-PAC have been shown to exhibit antiviral activities against HNoV surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1) at room temperature. Hence, the objectives of this research were (1) To …

The Effect Of Soluble Soybean Polysaccharide On Crystallization Behavior Of Lactose, Xueqian Shi

Masters Theses

Lactose can be recovered from cheese whey permeate concentrate by crystallization, and improving the recovery efficiency and purity of lactose crystals is significant to the profitability of the dairy industry. Lactose is also the major component in spray-dried dairy ingredients such as milk and whey powder. Lactose in spray-dried powder is amorphous and causes quality problems such as caking due to the crystallization of amorphous lactose during storage. Technologies are thus needed to improve the crystallinity of spray-dried lactose. In this study, soluble soybean polysaccharide (SSPS) was studied for the effects on lactose crystallization in aqueous solutions and during spray …

Northern Bobwhite (Colinus Virginianus) Habitat Selection On A Reclaimed Surface Mine In Western Kentucky, Ashley Marie Unger

Masters Theses

Reclaimed mines present an opportunity to provide large tracts of habitat for northern bobwhite (Colinus virginianus). Reclaimed mine sites are commonly planted to non–native species, including sericea lespedeza (Lespedeza cuneata) and tall fescue (Schedonorus phoenix), which can inhibit growth of more desirable plant species and limit favorable structure for bobwhite. Although bobwhite are found on reclaimed mine sites, there have been no studies documenting how bobwhites use various vegetation types common to reclaimed mine land. Habitat use studies can provide information on how bobwhite select vegetation types on these landscapes and help direct future …

Drd2 And Xkr4: A Genetic Approach To Fescue Toxicosis., Kristine Marie Ely

Masters Theses

Tall fescue (Lolium arundinaceum Schreb) is the most prevalent forage in the Mid-south United States due to its observed hearty nature and ability to withstand heavy grazing. This is due to a symbiotic relationship with an endophytic fungus (Neotyphodium coenophialum). This fungus produces ergot alkaloids, which can bind to many adrenergic, serotonergic, and dopaminergic receptors. One of the primary functions of dopamine is to inhibit prolactin response. Decreased growth, reproduction, lactation, and depressed serum prolactin concentrations are commonly observed in beef cattle grazing endophyte-infected tall fescue. These symptoms are collectively referred to as fescue toxicosis, and …

Impact Of Heat Stress On Germinal Vesicle Breakdown And Lipolytic Changes During In Vitro Maturation Of Bovine Oocytes, Leah Marie Hooper

Masters Theses

The main objective of this research was to examine the lipolytic changes in triglyceride and phospholipid as well as the incidence of germinal vesicle breakdown during IVM of heat-stressed oocytes compared to non-stressed oocytes. To this end, cumulus-oocyte complexes were matured for 0, 2, 4, 6 or 24 hIVM at 38.5 or 41.0°C (first 12 h only, then transferred to 38.5°C). Triglyceride and phospholipid levels decreased by 2 hIVM (P = 0.0009 and P = 0.0005, respectively) but remained fairly constant to 24 hIVM; lipid decline was not affected by maturation temperature. Elevated maturation temperature hastened meiotic progression by 4 …

Relationships Of Temperament, Endocrine, Reproductive, And Behavioral Parameters Measured During Performance Testing Of Bulls, Sierra Ashley Lockwood

Masters Theses

The aim of this study was to examine relationships between bull temperament, behavior, growth, endocrine, and reproductive parameters measured over an 84 d test period. Bulls (n = 65) were reared in 6 pens separated on BW and age. Pen scores were assigned on d -1, 27, 55 and 83. On d 0, 28, 56, and 84, exit velocity, BW, time it took each bull to leave the chute, bull order through chute, and hair and blood samples were recorded or collected. Frame score was calculated, carcass ultrasounds and breeding soundness exams were performed on d 84. ADG was calculated …

Diversity And Function Of Sulfur Cycling Microorganisms In Sediments From Subglacial Lake Whillans, Antarctica, Alicia Marie Purcell

Masters Theses

There is a growing consensus that metabolically and phylogenetically diverse assemblages of microorganisms mediate subglacial nutrient and elemental cycling. Subglacial Lake Whillans (SLW), located under 801 m of glacial ice, was recently penetrated using environmentally clean protocols. SLW is a permanently dark, cold (-0.5 °C [degrees Celsius]), and shallow (~2.2 m) freshwater lake beneath the West Antarctic Ice Sheet. The presence and diversity of key functional genes involved in dissimilatory sulfur oxidation and reduction were examined at various depths in two sediment cores taken from SLW. Our data show a diversity of sulfur transformation genes throughout the top 34 cm …

A Step Towards Understanding Of The Molecular Basis Of Ligand Promiscuity In The Aminoglycoside Modifying Enzymes, Sherin R. Raval

Masters Theses

Aminoglycosides have proven very useful in the treatment of infections; lately their effectiveness has been greatly reduced due to increasing resistance. Among many known mechanisms of resistance to aminoglycosides, enzymatic modification is the most prevailing. More than 14 aminoglycoside -N3-acetyltransferases- a class of aminoglycoside modifying enzymes, are known today. This study focuses on a pair of acetyl transferases: The aminoglycoside-N3- acetyltransferase IIIb (AAC-IIIb) and the aminoglycoside-N3- acetyltransferase IIa (AAC-IIa). AAC-IIa and AAC-IIIb are very similar in their amino acid sequence and structure – yet they have a strong difference in their substrate selectivity, kinetic …

Plant Functional Traits Mediate Above- And Belowground Species Interactions In Ecological Communities, Courtney E. Gorman

Masters Theses

Functional plant traits provide a means whereby species identity can influence above- and belowground community interactions. To examine the role of plant functional traits in shaping ecological communities, Chapter 1 examines how the evolution of functional differences between closely related groups of endemic and non-endemic species influence associated species interactions, and Chapter 2 examines how plant functional traits can influence associated community composition.

Evaluation Of The Over-Expression Of A Miscanthus X Giganteus Ppdk (C4ppdk1) In Switchgrass (Panicum Virgatum) For Improved Cold Temperature C4 Photosynthesis, Mathew Christian Halter

Masters Theses

Switchgrass (Panicum virgatum) has been proposed as a potential biofuel feedstock to aid in the displacement of petroleum-based combustible fuels over the course of the next several decades. Improving the yield potential of this perennial grass is therefore of economic interest. Increased net ethanol yields can be achieved in cellulosic feedstocks via two means: 1. Improved sugar release from digestible cell wall materials, 2. Increased overall biomass yield. The latter is the subject of this study.

As a C4 photosynthetic plant, switchgrass is highly productive in the hot, humid climate of the southeastern United States. By bypassing the …

Tillage, Cover Crop And Nitrogen Fertilization Effects On Soil Microbial Carbon Dynamics Under Long-Term Cotton Production, Molefi Jacob Mpheshea

Masters Theses

Effective soil management requires a deeper understanding of how internal soil carbon (C) works. This is vital as cycling is tightly linked with nutrient cycling processes. This study evaluated the effect of agronomic practices including tillage (no-till and tilled), cover crops (no cover, hairy vetch - Vicia villosa L, and winter wheat - Triticum aestivum. L ) and different N fertilizer rates ( 0, 34 and 101 kg N per hectare ) on soil microbial C dynamics as measured by soil microbial biomass C (SMBC) along with soil microbial respiration over the 2013 cotton growing season at Jackson, West …

The Benefits Of Ffa Membership As Part Of The Three-Circle Model In Agricultural Education, Chelsea Brooke Rose

Masters Theses

The purpose of this study was to understand the benefits of membership in the Future Farmers of America (FFA) student leadership organization among Tennessee FFA members by surveying members attending Camp Clements FFA Leadership Training Camp. The study focused on the fulfillment of FFA members’ basic human needs as defined by Abraham Maslow (1943). The three needs on which this study focused are: love and belonging, self-esteem, and self-actualization (1943). The study found that a majority of FFA members’ three basic human needs are met due to their involvement in career development events, leadership positions, and other FFA activities. Of …

Physiology Of Cold Acclimation And Deacclimation Responses Of Cool-Season Grasses: Carbon And Hormone Metabolism, Xian Guan

Masters Theses

Winter injury of cool-season turfgrasses in northern climates is a significant issue, leading to losses in turf cover and subsequent increased inputs for recovery. Despite the different potential causes for winter injury, the overall level of plant freezing tolerance has been shown to account for a majority of the variation in winter survival of grasses. Freezing tolerance is achieved through cold acclimation, based on a series of physiological and biochemical changes that increase cell stability at freezing temperatures. Winter injury can result from insufficient cold acclimation, or rapid cold deacclimation triggered by temperature fluctuations or freeze-thaw cycles. Previous research has …

Attention Modulates Erp Indices Of The Precedence Effect, Benjamin H. Zobel

Masters Theses

When presented with two identical sounds from different locations separated by a short onset asynchrony, listeners report hearing a single source at the location of the lead sound, a phenomenon called the precedence effect (Wallach et al., 1949; Haas, 1951). When the onset asynchrony is above echo threshold, listeners report hearing the lead and lag sounds as separate sources with distinct locations. Event-related potential (ERP) studies have shown that perception of separate sound sources is accompanied by an object-related negativity (ORN) 100-250 ms after onset and a late posterior positivity (LP) 300-500 ms after onset (Sanders et al., 2008; Sanders …

Properties Of Potential Substrates Of A Cyanobacterial Small Heat Shock Protein, Yichen Zhang

Masters Theses

Most proteins must fold into native three-dimensional structures to be functional. But, newly synthesized proteins are at high risk of misfolding and aggregating in the cell. Stress, disease or mutations can also cause protein aggregation. A cyanobacterial small heat shock protein, Hsp16.6, can act as a chaperone to prevent irreversible protein aggregation during heat stress. This thesis is focused on the properties of proteins that were associated with Hsp16.6 during heat stress, and which therefore may be “substrates” of Hsp16.6. Bioinformatics were used to determine if Hsp16.6 preferentially binds to proteins with certain properties, and biochemical studies were performed to …

Expression And Purification Of Human Lysosomal Β-Galactosidase From Pichia Pastoris, Sarah E. Tarullo

Masters Theses

Lysosomal storage diseases are genetically inherited diseases caused by the dysfunction of lysosomal enzymes. In a normal cell, lysosomal enzymes cleave specific macromolecules as they are transported to the lysosome. However, in diseased cells, these lysosomal enzymes are either absent or malfunctioning, causing macromolecular substrates to accumulate, becoming toxic to the cell. Over fifty lysosomal storage diseases have been identified, collectively occurring in one out of 7,700 live births. We investigated the lysosomal enzyme β-galactosidase (β-gal). In order to study the biochemistry and enzymology of this protein a robust expression system was needed. The GLB1 gene has been inserted into …

Age-Related Changes In Sleep-Dependent Consolidation Of Visuo-Spatial Memory, Akshata Sonni

Masters Theses

Healthy aging is associated with a reduction in slow-wave sleep (SWS), crucial for declarative memory consolidation in young adults; consequently, previously observed benefits of sleep on declarative learning in older adults could reflect a passive role of sleep in protecting memories from waking interference, rather than an active, stabilizing effect. To dissociate the passive and active roles of sleep, a visuo-spatial task was administered; memory was probed after a 12 hr interval consisting of either daytime wake or overnight sleep and post-wake/post-sleep stability of the memories was tested following task-related interference. Ninety five older adults (mean=65.43 yrs; SD=7.6 yrs) and …

Intuitive Eating, Attitudes To Food, And Body Size: A Comparison Between Nutrition Majors And Non-Majors, Katelyn Russell

Masters Theses

Dietitians are expected to deliver sound and scientifically objective advice to the general public, yet their personal beliefs and behaviors could influence delivery of nutrition care. Increased understanding of the personal attitudes and behaviors of dietitians concerning eating behavior and body image could help improve dietetic practice. Traditional nutrition education emphasizes cognitive eating, i.e., monitoring energy intake and comparing macronutrient intakes to the current acceptable ranges. Intuitive eating, however, promotes the release of cognitive eating in favor of greater attention to physiologic cues, or “body wisdom”. We hypothesized that nutrition students in a traditional curriculum would report eating less intuitively …

Volatile Profiles And Resistance To Herbivory In Eastern Hemlock, Elizabeth A. Mckenzie

Masters Theses

Eastern hemlock hosts the hemlock woolly adelgid, an introduced sap-feeding insect that causes rapid deterioration of the host. Like most conifers, eastern hemlock produces a variety of constitutive and induced defenses, primarily terpenoids. To explore the relationship of terpenoid defenses with adelgid infestations, we artificially infested hemlocks at a forest site and a plantation site, and compared their terpenoid concentrations to those in control trees. Infested trees showed lower terpenoid concentrations than control trees, suggesting that eastern hemlock not only fails to induce production of terpenoids in response to adelgid infestation, but becomes less able to produce carbon-based defenses due …

Assessing Wild Canid Distribution Using Camera Traps In The Pioneer Valley Of Western Massachusetts, Eric G. Leflore

Masters Theses

With the ever-increasing human population, more people reside in urban areas than ever before; this is having marked effects on the landscape and in turn, wildlife. This study uses automatically triggered wildlife cameras to assess the distribution of three carnivore species (coyotes, Canis latrans; red foxes, Vulpes vulpes; and gray foxes, Urocyon cinereoargenteus) around the Pioneer Valley of Massachusetts in relation to a gradient of human development. Cameras were placed at 141 locations within the 320-km² study area over the course of three field seasons (3,052 trap nights). Relative abundances for fourteen other species and site …