Biology Commons^™

Morphological Response In Sister Taxa Of Woodrats (Genus: Neotoma) Across A Zone Of Secondary Contact, Michaela M. Koenig

Master's Theses

This study focuses on a secondary contact zone between two sister species of woodrat, Neotoma fuscipes (dusky-footed woodrat) and N. macrotis (big-eared woodrat). Along the Nacimiento River, on the border of southern Monterey and northern San Luis Obispo counties, the ranges of these sister species of woodrats meet and overlap forming a secondary contact zone. The zone of secondary contact is estimated to include a 500-meter (~1,650 linear feet) portion of the Nacimiento River riparian corridor.

This research examines quantifiable morphological change that is likely associated with heightened inter-specific competition within the contact zone. When in sympatry the sister species …

Multi-Stress Proteomics: The Global Protein Response To Multiple Environmental Stressors In The Porcelain Crab Petrolisthes Cinctipes, Michael A. Garland

Master's Theses

Global climate change is increasing the number of hot days along the California coast as well as increasing the incidence of off-shore upwelling events that lower the pH of intertidal seawater; thus, intertidal organisms are experiencing an increase in more than one stress simultaneously. This study seeks to characterize the global protein response of the eurythermal porcelain crab Petrolisthes cinctipes to changes in thermal, pH, and tidal regime treatments, either combined or individually. The first experiment examined temperature stress alone and sought to determine the effect of chronic temperature acclimation on the acute heat shock response. We compared the proteomic …

An Investigation Of The Effect Of Malathion On Adaptive Plasticity Of Pseudacris Sierra, Michael Jonathan Maples

Master's Theses

This thesis is composed of two chapters. Chapter one reviews what is known about adaptive plasticity in response to predators, describes the physiological systems involved in such plasticity, and outlines the evolutionary consequences of adaptive plasticity. Chapter two describes a scientific experiment that investigates how malathion may impact adaptive plasticity in the Sierran Treefrog, Pseudacris sierra. Anuran tadpoles suffer high mortality rates due to predation. In response to strong selective forces relating to these high predation rates, tadpoles evolved the ability to adaptively respond to predators through morphological and behavioral plasticity. The morphological and behavioral responses are varied and depend …

Latitudinal Variation In Thermal Tolerance And Preference Of Fundulus Notatus And F. Olivaceus: Implications For Temperature Mediated Reproductive Isolation, Laura Kristin Stewart

Master's Theses

Temperature is one of the most pervasive and influential abiotic factors affecting the life histories of fish, regulating a host of physiological processes and influencing behavioral thermoregulation. Fundulus notatus, the blackstripe topminnow, and F. olivaceus, the blackspotted topminnow, are widely distributed species located in drainages along the northern part of Gulf of Mexico (30°N latitude) and as far north as southern Illinois (39°N latitude). However, F. notatus has a much broader range reaching up into the Great Lakes (43°N latitude). Due to their broad geographical range, these populations inhabit a wide range of thermal regimes, thus …

Naturalists’ Perspectives On The Use Of Mobile Technology During A Nature Hike, Aubin Marishka Radzewicz St. Clair

Master's Theses

Naturalists act as our link between scientific knowledge and the public’s understanding of natural history and conservation efforts. In order for them to succeed, they need access to reference materials as well as up-to-date information (Mankin, Warner, & Anderson, 1999). Incorporating mobile technology (i.e. tablets) into naturalists’ endeavors in natural history and environmental education can be used as supportive and educational tools. My project investigated how newly trained naturalists used tablet technology while leading groups of children on nature hikes. I investigated naturalists’ views on the use of mobile technology as a tool during the hikes. My research was guided …

Elucidating The Molecular Function Of Reprolysin Metalloproteases In Tick-Host-Pathogen Interaction, Jaclyn Bo Williams

Master's Theses

Ticks are ectoparasites that attach to their host for many days to weeks, feeding to engorgement and continuing their species life cycle. The mechanisms behind the successful feeding and manipulation of host immune responses have been associated with the secretion of their specialized saliva. Tick saliva includes a variety of modulatory molecules that must disrupt and counteract defense mechanisms, including a variety of proteases. Reprolysin Metalloproteases, in the Zn²⁺ dependent family, is secreted as a proenzyme and is shown to have proteolytic activity, degrading fibrinogen and gelatinase activity, as well as disturbing homeostasis¹². Previous work with …

The Roles Of Human Cytomegalovirus Us27 Gene Product During Virus Infection, Carolyn C. Tu

Master's Theses

Human cytomegalovirus (HCMV) is a widespread pathogen that causes lifelong latent infection. Successful persistence of HCMV in healthy individuals involves extensive manipulation of host cellular functions and immune responses. HCMV encodes four genes for putative G protein-coupled receptors (GPCRs): US27, US28, UL33, and UL78. The US28 gene product is a functional chemokine receptor that exhibits a variety of signaling outcomes. In contrast, the US27 gene product is an orphan with no known chemokine ligands. We have found that US27 triggers several biological effects: increased cellular proliferation, changes in gene expression, and enhanced signaling of cellular chemokine receptor CXCR4. Enhanced cell …

Transcriptional Regulation By Dax-1 In Pluripotent And Differentiated Cells, Alexandra C. Maramba

Master's Theses

DAX-1, an orphan nuclear hormone receptor, acts mainly as a repressor through transcriptional protein complexes. Its unique structure and specific expression raises questions as to what its precise interactions are and how it mediates its repressive function. While it is known to play a role in sexual development and adrenal insufficiency, expression in certain types of cancer suggests additional functions and interactions. Knock in of DAX-1 into a low-DAX-1 expressing cancer cell line has been previously observed to increase apoptosis, while, inversely, down in a high-DAX-1 expressing cancer cell line shows a decrease in apoptosis. Target genes that belong to …

Detection Of Hcmv Viral Il-10 (Vil-10) In Healthy Blood Donors, Vivian P. Young

Master's Theses

Human cytomegalovirus (HCMV) is widespread in the general population and can establish lifelong latency with expression of a limited subset of viral genes. The UL111A gene is expressed during both lytic and latent infection, and at least two protein isoforms are produced. During lytic infection, the full length transcript yields cmvIL-10, a potent immunosuppressive viral ortholog of human IL-10 (hIL-10). Alternative splicing of the UL111A transcript yields a truncated protein, LAcmvIL-10, which is expressed during both lytic and latent infection but with a limited range of immunosuppressive functions. The two viral cytokines, collectively termed viral IL-10 (vIL-10), are identical in …

Seasonal Variation In Corticosterone, Stress Responses, And Physiology In The Northern Cardinal Cardinalis Cardinalis, Benjamin Matthew Duckworth

Master's Theses

Seasonal regulation of the adrenocortical response (e.g., ‘stress response’) appears to be ubiquitous in mid- to high-latitude vertebrates. Northern Cardinals (Cardinalis cardinalis) are a Temperate dwelling passerine of Tropical-descent with a wide species range (tropics to Northern Temperate zones). This species encounters a wide variety of environmental conditions and strong seasonality, however corticosterone (CORT, the main adrenal stress hormone) has not been studied with regards to changes in seasonal levels. I initially analyzed samples from cardinals collected between 2007-2011 from the Lake Thoreau Environmental Research and Educational Center (Hattiesburg, Mississippi, USA). The data suggested seasonal differences of CORT, with higher …

Stressed Induced Changes In Karenia Brevis Ribosomal Rna, David Scott Jayroe

Master's Theses

Karenia brevis is a toxic marine dinoflagellate that causes harmful algal blooms (HABs), also known as red tides, in the Gulf of Mexico. These blooms are responsible for massive fish kills, shellfish bed contaminations, adverse human health effects, and vast economic loss. For these reasons, extensive research has gone into understanding the mechanisms and dynamics of bloom behavior by studying K. brevis in the field and in the lab. In order to understand higher order bloom behavior and dynamics it is imperative to understand K. brevis at the cellular level. In growing K. brevis in vitro under a variety of …

Impacts Of The Deepwater Horizon Oil Spill On Microbial-Mediated Cellulose Decomposition In Mississippi Gulf Coast Salt Marshes, Jerrid Shawn Boyette

Master's Theses

Field studies were conducted to examine the effects of the Deepwater Horizon oil spill on rates of marsh organic matter decomposition. Decomposition in surface and subsurface marsh sediments was assessed in stands of Spartina alterniflora and Juncus roemerianus in 9 Mississippi Gulf Coast marshes exposed to differing oiling intensities. The cotton strip bioassay technique was used as a proxy for cellulose decomposition. In addition, rates of microbial respiration, fungal biomass (ergosterol) and nutrients (C:N, C:P) of surface sediment cotton strips were also quantified. Subsurface cotton strip decay, as determined by losses in tensile strength, were significantly different among marsh …

Increasing Expression Of Hepatitis B Surface Antigen In Maize Through Breeding, Erin Suzanne Miller

Master's Theses

The hepatitis B virus (HBV) is a common virus, with two billion people infected worldwide. It causes approximately 600,000 deaths each year, despite the availability of an effective vaccine since 1982. Maize as a platform for oral vaccination can supply a heat stable vaccine, which does not require syringes or trained personnel to administer. The Hepatitis B Surface antigen was transformed into maize and this seed was used to evaluate expression levels through the breeding process. The transgene was transferred into two elite maize inbreds by backcrossing. Highest expressing ears were selected each generation until approximately 99% commercial parent was …

Identification Of Saccharina Groenlandica (Phaeophyceae) Around The Svalbard Archipelago: Dna Barcoding Using Cytochrome C Oxidase Subunit 1 (Coi), Anniken Lydon

Master's Theses

In the Arctic, brown algae (kelps) and seaweeds are ecologically important: providing habitat, protection, and nutrients for invertebrate and vertebrate species living in nearshore environments. Migrations of biota between the North Pacific and North Atlantic Oceans have occurred periodically during Earth’s history leading to colonization of the Arctic Ocean. Around 3.5 Mya the “Great Trans-Arctic Biotic Interchange” occurred and the Laminariales order of kelp, thought to be of North Pacific origin, underwent a massive radiation and speciation event around the Arctic Ocean. Phylogenetic analysis performed on “Laminaria-like” specimens collected from six sampling locations around the Svalbard Archipelago identified …

The Proteomic Response Of The Carcinus Maenas Y-Organ Over The Course Of The Molt Cycle, Mark S. Hamer

Master's Theses

Molting in arthropods is a complex process governed by regulatory mechanisms that have evolved and adapted over millennia to allow these animals to grow, despite being confined by a hardened exoskeleton. We isolated the molt-regulating Y-organs (YO) from the common shore crab Carcinus maenas at molt stages B, C_1-3, C₄, and D₀ to assess how changes in protein abundances might underline the unique physiology of each of these stages. We found that changes in protein abundance were most notable in the postmolt stages (B and C_1-3), where an increase in energy metabolism and …

Experimental Evolution Of Specialism In A Wild Virus, Alexander Kula

Master's Theses

A pathogen's ability to successfully replicate and persist within a new host population is fraught with obstacles. While an expanded host-range allows for a greater chance at successful replication, such generalists are typically outcompeted by species which have specialized and adapted host-specific features. Although the most ubiquitous species on earth, very few bacteria-infecting viral species (bacteriophages) with truly broad host-ranges have been identified; this is partially due to the fact that only a small fraction of bacteria (and thus likely hosts) are amenable to laboratory conditions. Nevertheless, the processes of expanding as well as narrowing host-range are not well understood …

Expression And Characterization Of Ecm14, A Metallocarboxypeptidase From Saccharomyces Cerevisiae, Matthew James Schott

Master's Theses

Metallocarboxypeptidases are found in most organisms and function in the digestion and maturation of proteins. Ecm14 is a putative metallocarboxypeptidase found in the yeast Saccharomyces cerevisiae vacuole. The function of Ecm14 as an enzyme has been unclear due to the presence of active site amino acids not typically found in metallocarboxypeptidases, suggesting either no enzymatic activity or a unique mechanism. In order to investigate the enzymatic mechanism of Ecm14, expression of histidine-tagged Ecm14 protein was attempted in human HEK293T cell culture, S. cerevisiae, and baculovirus expression systems. No expression was detected in HEK293T cells in preliminary experiments. Expression in the …

Shifting The Stress Curve: Using "Stress Inoculation" And Exercise To Promote Resilience, Mikyung Kim

Master's Theses

Problem

Stress influences an organism’s physiological systems via an inverted u-shaped curve: An optimum amount of stress will optimize body functions, but too little stress or too much stress for long periods of time can impair body functions. Researchers have been very interested in exploring the mechanisms that may “delay the tipping point” between the positive and negative effects of stress. A rightward shift in the stress curve would allow one to maintain optimal performance even at higher or more prolonged stress levels. The molecular and cellular mechanisms that underlie this rightward shift could result in resilience, clinically defined as …

Selective Processing By The L3 Auditory Interneuron In Acheta Domesticus : Juvenile Hormone Iii And Protein Kinase C, Ashley Ranae Lynch

Master's Theses

Juvenile Hormone III (JHIII) is a prolific and essential hormone in insects, controlling many aspects of insect physiology such as egg development, nymphal and larval maturation, diapause and metamorphosis. In female crickets, Acheta domesticus, JHIII increases selectivity in phonotactic behavior, narrowing phonotactic choices for Syllable Periods (SPs) of the Calling Songs (CSs) that most closely resemble the natural call of the male. JHIII has been suggested to work through a pathway that activates the protein kinase C (PKC) molecule. Chelerythrine Chloride (CC) is a potent inhibitor of PKC action. This study analyzes the responses of the L3 auditory interneuron, which …

Dna Methylation Patterns Of Specific L1 Loci On The Short Arm Of Chromosome 21, Sarah Ann Tincher

Master's Theses

While 10-15% of the human genome is composed of heterochromatic DNA, these regions are not included in the completed genome sequence. The short arm of chromosome 21 (HC21p) serves as a model for understanding the structure and function of heterochromatin. LINE-1 (L1) retrotransposons are underrepresented in heterochromatin, including HC21p, and have not been extensively studied in these regions. However, there are disproportionately more full length L1s on HC21p than in euchromatic genomic regions. Decreased DNA methylation in the promoters of these L1s on HC21p may allow them to facilitate heterochromatin formation, which would be analogous to their proposed role in …

Epigenetic Regulation Of Nuclear Hormone Receptor Dax-1, Michael B. Heskett

Master's Theses

DAX-1 (NR0B1) is an orphan nuclear receptor that plays a key role in the development and maintenance of steroidogenic tissue in mammals. Dax-1 is also expressed in mouse embryonic stem (ES) cells and is required to maintain pluripotency. Duplication of the X-chromosome in the region containing the NR0B1 gene results in sex reversal, and mutations in NR0B1 cause adrenal hypoplasia congenita. DAX-1 has been observed to act as a corepressor of other nuclear receptors including androgen receptor (AR), estrogen receptor (ER), and steroidogenic factor 1 (SF-1). In addition to pluripotent ES cells, DAX-1 is primarily expressed in select tissues of …

Examining The Role Of Dax-1 In Regulation Of Cell Proliferation In Human Breast Cells, Amy E. Scandurra

Master's Theses

DAX-1 is a member of the Nuclear Hormone Receptor superfamily and acts as a transcriptional repressor. DAX-1 plays an important role in the development of adrenal and gonadal tissues. In addition to its role in normal cell development and differentiation, DAX-1 appears to have some influence on the progression of cancer. This work aims to examine the role of DAX-1 in regulation of proliferation in breast cancer. In our study, we have expressed DAX-1 in a DAX-1 deficient breast cancer cell line as well as knocked down DAX-1 expression in normal DAX-1 positive breast cells. Through these experiments, we were …

The Conservation Genetics Of Two Emydid Turtles: Emydoidea Blandingii And Malaclemys Terrapin, Charlotte Lizana Petre

Master's Theses

Conservation of turtles is complicated by their sensitivity to habitat degradation and overexploitation. I used microsatellites and standard population genetic analyses to explore genetic diversity, population structure, paternity and demographic history in two emydid turtles that are currently experiencing threats to their survival. The Blanding’s turtle, Emydoidea blandingii, has experienced habitat fragmentation throughout its range, and this study focuses on a population in Massachusetts where hatchlings from one population are being translocated to establish a new population. I found evidence of multiple paternity within clutches and found no significant reduction in genetic diversity when comparing the source population and …

The Ontogeny Of Whistle Production In Infant Atlantic Bottlenose Dolphins (Tursiops Truncatus) During The First Thirty Days Of Life, Brittany Leigh Jones

Master's Theses

The manner in which dolphin calves acquire their whistle repertoire is largely unknown. This paper focuses on whistle development in four bottlenose dolphin calves during the first thirty days of life in order to increase our understanding of the early emergence of whistles and whistle-like vocalizations. The acoustic parameters of whistle-type vocalizations (i.e., whistles and whistlesquawks) that coincided with a bubblestream emission from the focal calf and/or its mother were analyzed, as were the behavioral states of the mother-calf pair during the emission of such vocals. Mother and calf whistle rates are inversely related, with the mother whistling more often …

Characterizing Populations Of Non-Coding Rnas In Karenia Brevis At Different Times Of The Diel Cycle, Scott Boyd Anglin

Master's Theses

Karenia brevis is a mixotrophic, marine dinoflagellate found in the Gulf of Mexico that generates periodic, if not annual, harmful algal blooms (also known as “red tides”) in certain coastal areas. In an effort to better understand the biology of this organism, a functional genomics project has been initiated. As part of that project, it has been determined that a significant number of natural antisense transcripts (NATs) as well as double-stranded RNA (dsRNA) molecules exist within the transcriptome of K. brevis. I hypothesize that the non-coding NATs, similar to microRNAs (miRNAs) in other organisms play a role in regulating …

Identification And Characterization Of Msab Gene Involved In Biofilm Formation And Virulence In Staphylococcus Aureus, Amelsaad Elbarasi

Master's Theses

Staphylococcus aureus is an important human pathogen that causes a wide variety of life-threatening infections ranging from minor skin and oral infections to severe infections, such as bacteremia, pneumonia, osteomyelitis, or endocarditis due to the presence and secretion of a large number of virulence factors that are controlled by global virulence regulators in complex networks. Furthermore, S. aureus infections have become a threat to public health because of their high potential to form biofilm, and their ability to resist a wide range of antibiotics has exacerbated further. Therefore, understanding the regulatory networks and developing a drug targeting these networks has …

Role Of Msaa Gene In Regulation Of The Msaabcr Operon And Biofilm Development In Staphylococcus Aureus, Ahmed Alzuway

Master's Theses

Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance …

The Role Of Sirtuin Inhibitors On The Proteomic Responses Of The Mussels Mytilus Galloprovincialis And Mytilus Trossulus To Menadione Induced Oxidative Stress, Hayley C. Chilton

Master's Theses

Global climate change imposes physiological constraints on marine ecosystems that can alter the distribution of intertidal organisms. In one such instance, the native cold-adapted mussel Mytilus trossulus is being replaced along its southern range by the invasive warm-adapted Mytilus galloprovincialis. These blue mussels occur throughout rocky intertidal zones where they are subjected to greatly varying environmental conditions known to induce oxidative stress. We hypothesize that while under acute stress, related Mytilus congeners undergo a shift in redox potential from NADH-fueled respiratory pathways to pathways producing NADPH as a way to decrease the production of reactive oxygen species (ROS) and …

Optimization Of Growth Parameters For Algal Regrowth Potential Experiments, Chadwick D. Boggess

Master's Theses

Water cost is one of the key deterrents in making algal biofuels a feasible alternative to traditional petroleum fuels. Research into recycling of algal media was conducted in a laboratory setting at the California Polytechnic State University in San Luis Obispo. A growth assay was created to allow for algal cultures, specifically Ward’s Chlorella sp., to proliferate in sealed culture vessels. Bold’s Basal Medium (BBM) was selected as the media due to its extensive use with freshwater algal strains. However, this medium can limit algal growth through nutrient limitation and it became necessary to augment the original recipe. 50mM …

Investigation Of Chromosome Size Effect On The Rate Of Crossovers In The Meiotic Yeast Saccharomyces Cerevisiae, Lanie Maria Galland

Master's Theses

Meiosis is a specialized type of cell division characterized by a single round of DNA replication and two rounds of chromosome segregation, ultimately resulting in four haploid cells. During meiosis I, chromosomes align and reciprocal recombination results in the formation of a crossover, creating the tension required to properly segregate homologs during the first round of meiosis.

Two mechanisms involved in regulating the occurrence of crossing over are assurance and interference. Crossover assurance describes the phenomenon that at least one crossover will form between each pair of homologous chromosomes during prophase I. Crossover interference, on the other hand, describes the …