Life Sciences Commons^™

Wood Decomposition In A Warmer World, Emily Elizabeth Austin

Doctoral Dissertations

Climatic warming is altering species distributions and ecosystem functions across the globe. Wood is an important carbon pool and the fungal communities in wood are relatively simple compared to those in soil. These factors make decomposing wood an ideal system for exploring the influence of decomposer community on the response of decomposition to warming. My research has focused on the effects of warming wood decomposition rates and wood decomposing communities. Using field and lab- based manipulative experiments and field observations I explore the influence of tree species, wood decomposition stage, geography and warming on fungal community structure and activity. In …

Small Scale Population Structure Of Pityopsis Ruthii And P. Graminifolia Var. Latifolia, Sarah Lynn Boggess

Masters Theses

Pityopsis graminifolia var. latifolia (Michx.) Small var. latifolia (Fern.) or narrowleaf silkgrass is an herbaceous perennial native to the southeastern United States and northern Central America. Pityopsis ruthii (Small) Small is an endangered plant endemic to the Hiwassee and Ocoee Rivers in Polk County, Tennessee. Little is known about the genetic diversity and population structure of both Pityopsis species as well as the phylogenic relationships between the species. In this study, 16 microsatellite loci were used to assess genetic diversity and population structure of 261 individuals of P. ruthii (n=167) and P. graminifolia var. latifolia (n=76). Pityopsis ruthii is …

Population Demographics And Genetic Structure Of Black Bears In Coastal Louisiana, Jesse Charles Troxler

Masters Theses

The range and abundance of the Louisiana black bear (Ursus americanus luteolus) were greatly diminished during the 20th century. This subspecies was reduced to 3 small, isolated subpopulations in Louisiana as bottomland hardwood habitat was converted to agriculture. These bears were listed as threatened by the U.S. Fish and Wildlife Service in 1992 and a recovery plan was published in 1995. Recovery requires estimates of population parameters to evaluate current population status and future viability. I conducted a mark-recapture study from 2010 to 2012 to estimate demographic parameters of the coastal population of Louisiana black bears. Because inbreeding …

Body Size Variation In Two Adjacent Populations Of Black Kingsnakes (Lampropeltis Nigra) In East Tennessee, Jesse Weber, Joshua Ennen

Chancellor’s Honors Program Projects

No abstract provided.

Introduction To L.R. Hesler's Mushroom Notebooks, R H. Petersen

L. R. Hesler’s Mushroom Notebooks

No abstract provided.

High Variance In Reproductive Success Generates A False Signature Of A Genetic Bottleneck In Populations Of Constant Size: A Simulation Study, Sean M. Hoban, Massimo Mezzavilla, Oscar E. Gaggiotti, Andrea Benazzo, Cock Van Oosterhout, Giorgio Bertorelle

Faculty Publications and Other Works -- General Biology

Background

Demographic bottlenecks can severely reduce the genetic variation of a population or a species. Establishing whether low genetic variation is caused by a bottleneck or a constantly low effective number of individuals is important to understand a species’ ecology and evolution, and it has implications for conservation management. Recent studies have evaluated the power of several statistical methods developed to identify bottlenecks. However, the false positive rate, i.e. the rate with which a bottleneck signal is misidentified in demographically stable populations, has received little attention. We analyse this type of error (type I) in forward computer simulations of stable …

Mechanisms Contributing To The Emergence Of Ranavirus In Ectothermic Vertebrate Communities, Roberto M. Brenes

Doctoral Dissertations

Ranaviruses have been linked to amphibian die-off events in ectothermic vertebrates worldwide. Differences in susceptibility and capacity of transmission among and within classes are poorly understood. My goal was to determine possible mechanisms influencing susceptibility to ranavirus infection in amphibian species and other aquatic vertebrate taxa, as well as the capacity of transmission between classes and the effects of amphibian community composition on ranavirus transmission. I tested 16 amphibian species from USA, Europe, and the pet trade, expanding an existing database developed by the Center for Wildlife Health to 35 amphibian species from 9 families. I also tested the susceptibility …

Cellular And Population Plasticity Of Helper Cd4(+) T Cell Responses, G Magombedze, P B. Reddy, S Eda, V V. Ganusov

Faculty Publications and Other Works -- General Biology

Vertebrates are constantly exposed to pathogens, and the adaptive immunity has most likely evolved to control and clear such infectious agents. CD4(+) T cells are the major players in the adaptive immune response to pathogens. Following recognition of pathogen-derived antigens naïve CD4(+) T cells differentiate into effectors which then control pathogen replication either directly by killing pathogen-infected cells or by assisting with generation of cytotoxic T lymphocytes (CTLs) or pathogen-specific antibodies. Pathogen-specific effector CD4(+) T cells are highly heterogeneous in terms of cytokines they produce. Three major subtypes of effector CD4(+) T cells have been identified: T-helper 1 (Th1) cells …

Studies On Solo Working Mechanism In The Meiosis Of Drosophila Melanogaster, Qian Ma

Masters Theses

In eukaryotes, sister chromatids are closely aligned due to cohesion, a process essential for chromosome pairing and segregation during both mitosis and meiosis. A conserved cohesin complex in a ring structure is composed of four subunits, including each of these four members or their homologs, SMC1, SMC3, SCC1/RAD21/REC8, and SCC3/SA. Up to now, no REC8 homolog has been identified in the meiosis of Drosophila. SOLO is a meiotic protein required for accurate chromosome segregation, centromere cohesion, and cohesin complex localization in Drosophila meiosis. In addition, SOLO is required for synapsis and recombination in Drosophila female meiosis.

In this study, …

Trends In Borrelia Spp. Prevalence In Ixodes Spp. Ticks From The Southeastern Coastal United States, Lauren Paul Maestas

Masters Theses

The Lyme borreliosis (LB) cycle, involving Ixodes scapularis and Borrelia burgdorferi sensu stricto (Bbss), is well documented in the northeastern US, where LB is becoming increasingly prevalent. In coastal North Carolina, I. affinis has been shown to have a higher incidence of Bbss than I. scapularis. My objectives were, to assess changes in prevalence of Bbss in Ixodes spp. along a transect from Virginia to Florida, and to assess the value of dogs and mesomammals as sentinels for spread of Borrelia burgdorferi sensu lato.

Ixodes spp. were collected at sites from 37.4^o N to 30.0^{o …}

Prevalence And Transmission Potential Of Borrelia Burgdorferi In Three Species Of Wildcaught Plestiodon Spp. Skinks Of The Southeastern United States, Teresa Dianne Moody

Masters Theses

In the southeastern United States, blue-tailed skinks (Plestiodon spp.) are important hosts for Ixodes scapularis ticks, the principal vector of Lyme disease (LD) in this region. Skinks and other southeastern lizards are not thought to be reservoir competent for Borrelia burgdorferi sensu stricto (Bbss), the etiological agent of LD in the United States. . Lizard-feeding by southeastern I. scapularis may tend to suppress sylvatic cycles of B. burgdorferi, and thus may be an important reason why LD case rates in the Southeast are much lower than in the Northeast and upper Midwest. Nevertheless, some skinks …

Undergraduate Perception Of Introductory Lecture And Laboratory Biology Instructors At The University Of Tennessee Knoxville, Katharina Denise Kendall

Doctoral Dissertations

Undergraduate students entering the higher education system are often unaware of the diverse teaching and learning community they will encounter, including the different instructor types who will teach their classes. In order to accommodate the growing numbers of enrolled students, the higher education system is increasingly reliant on contingent instructors such as non-tenure track faculty members and graduate teaching assistants (GTAs). This dissertation explores undergraduate student perspective of the different instructor types who teach introductory biology courses, with a focus on the University of Tennessee, Knoxville (UTK). The goal of this work is to provide insight regarding how perceived differences …

Development And Application Of Mass Spectrometry-Based Proteomics To Generate And Navigate The Proteomes Of The Genus Populus, Paul Edward Abraham

Doctoral Dissertations

Historically, there has been tremendous synergy between biology and analytical technology, such that one drives the development of the other. Over the past two decades, their interrelatedness has catalyzed entirely new experimental approaches and unlocked new types of biological questions, as exemplified by the advancements of the field of mass spectrometry (MS)-based proteomics. MS-based proteomics, which provides a more complete measurement of all the proteins in a cell, has revolutionized a variety of scientific fields, ranging from characterizing proteins expressed by a microorganism to tracking cancer-related biomarkers. Though MS technology has advanced significantly, the analysis of complicated proteomes, such as …

Characterization Of The Apoptotic Functions Of The Hid Hmolog Isolated From Megaselia Scalaris, Shannon Smith

Chancellor’s Honors Program Projects

No abstract provided.

Microarray Analysis Of Mrna Translation State In Arabidopsis Thaliana, Bayu Sisay Tiruneh

Masters Theses

The synthesis of proteins – translation – is one of the cellular processes that consume a great deal of energy. Genome-wide assays performed in Arabidopsis and other organisms have revealed that the translation status of mRNAs responds dramatically to different stresses and environmental and growth signals. Similar assays have revealed how translation of specific mRNAs is perturbed by genetic mutations in eukaryotic translation initiation factors (eIFs). I performed genome-wide analyses of translation state in A. thaliana seedlings with mutant genotypes for a specific eIF (subunit h of eIF3) and the large ribosomal protein, L24 (RPL24B). Using data from prior microarray …

Phosphorylation Regulates Myosin Driven Organelle Movements, Peter Andrew Duden

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Cytoplasmic streaming in plant cells is the continuous flow of cytoplasm and organelles throughout the cell, with the first observation of cytoplasmic streaming being publicized in 1774. However, the mechanism of cytoplasmic streaming remained unclear until components of the cytoskeleton were researched. Research now supports that the motive force generating cytoplasmic streaming is the interaction of myosin XI motor proteins with organelles while sliding along actin filaments. From this, a key topic of interest is how myosin driven organelle movement is regulated. Our research focuses on whether phosphorylation affects the regulation of myosin XI motor proteins. Specifically, the goal of …

Metabolic Rescue Of “Glucose Addicted” Cancer Cells In Vitro, Paolo Vignali

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Transformations in the glycolytic metabolism of neoplasms modulate their robust cellular division. This characteristic leads to an “addiction” to glucose for continued proliferation and viability. This study investigated whether glucose metabolites could rescue cellular viability in glucose-starvation conditions, a model of the inter-tumoral nutrient-deficient environment. Findings illustrated potential cellular viability rescue with pyruvate addition in glucose-deprived conditions, yet the same potential was not observed with lactic acid, a metabolite that exists at characteristically high concentrations within the intertumoral microenvironment. These results could implicate a predominance of certain metabolic pathways in nutrient-starved cells. Molecular transport capacities across plasma membranes are tied …