Life Sciences Commons^™

Marine Reptiles, Arne R. Rasmessen, John D. Murphy, Medy Ompi, J. Whitfield Gibbons, Peter Uetz

Study of Biological Complexity Publications

Of the more than 12,000 species and subspecies of extant reptiles, about 100 have re-entered the ocean. Among them are seven species of sea turtles and about 80 species and subspecies of sea snakes, as well as a few other species that are occasionally or regularly found in brackish waters, including various other snakes, the saltwater crocodile, and the marine iguana of the Galapagos Islands. The largest group of marine reptiles, the sea snakes, occur in the tropical and subtropical waters of the Indian and Pacific Oceans from the east coast of Africa to the Gulf of Panama. They inhabit …

Air Pollution & The Brain: Subchronic Diesel Exhaust Exposure Causes Neuroinflammation And Elevates Early Markers Of Neurodegenerative Disease, Shannon Levesque, Michael J. Surace, Jacob Mcdonald, Michelle L. Block

Anatomy and Neurobiology Publications

Background

Increasing evidence links diverse forms of air pollution to neuroinflammation and neuropathology in both human and animal models, but the effects of long-term exposures are poorly understood.

Objective

We explored the central nervous system consequences of subchronic exposure to diesel exhaust (DE) and addressed the minimum levels necessary to elicit neuroinflammation and markers of early neuropathology.

Methods

Male Fischer 344 rats were exposed to DE (992, 311, 100, 35 and 0 μg PM/m³) by inhalation over 6 months.

Results

DE exposure resulted in elevated levels of TNFα at high concentrations in all regions tested, with the exception …

Chronic Apocynin Treatment Attenuates Beta Amyloid Plaque Size And Microglial Number In Happ(751)Sl Mice, Melinda E. Lull, Shannon Levesque, Michael J. Surace, Michelle L. Block

Anatomy and Neurobiology Publications

Background

NADPH oxidase is implicated in neurotoxic microglial activation and the progressive nature of Alzheimer's Disease (AD). Here, we test the ability of two NADPH oxidase inhibitors, apocynin and dextromethorphan (DM), to reduce learning deficits and neuropathology in transgenic mice overexpressing human amyloid precursor protein with the Swedish and London mutations (hAPP(751)SL).

Methods

Four month old hAPP(751)SL mice were treated daily with saline, 15 mg/kg DM, 7.5 mg/kg DM, or 10 mg/kg apocynin by gavage for four months.

Results

Only hAPP(751)SL mice treated with apocynin showed reduced plaque size and a reduction in the number of cortical microglia, when compared …

Development Of Melanopsin-Based Irradiance Detecting Circuitry, David S. Mcneill, Catherine J. Sheely, Jennifer L. Ecker, Tudor C. Badea, Duncan Morhardt, William Guido, Samer Hattar

Anatomy and Neurobiology Publications

Background

Most retinal ganglion cells (RGCs) convey contrast and motion information to visual brain centers. Approximately 2% of RGCs are intrinsically photosensitive (ipRGCs), express melanopsin and are necessary for light to modulate specific physiological processes in mice. The ipRGCs directly target the suprachiasmatic nucleus (SCN) to photoentrain circadian rhythms, and the olivary pretectal nucleus (OPN) to mediate the pupillary light response. How and when this ipRGC circuitry develops is unknown.

Results

Here, we show that some ipRGCs follow a delayed developmental time course relative to other image-forming RGCs. Specifically, ipRGC neurogenesis extends beyond that of other RGCs, and ipRGCs begin …

Behavior And Development Of Red-Eyed Treefrogs During Metamorphosis [Poster], Robin Greene, Clay Noss, Tobias Lanberg, James R. Vonesh, Karen Warkentin

Biology Presentations

Anuran metamorphosis is an extreme transformation from tadpole to frog that involves tremendous morphological and behavioral change. During this transition (Gosner stages 42-46), metamorphs are exposed to both aquatic and terrestrial selective pressures (e.g., predators, desiccation). Their behavior may be crucial for survival, but it is not well studied. Our goal was to describe morphological and behavioral patterns during metamorphosis in red-eyed treefrogs, Agalychnis callidryas. We first quantified development through metamorphosis by measuring and staging 25 wild-caught individuals every 8 h. We then conducted field behavioral observations of 37 metamorphs, at various developmental stages, that had emerged from a …

The Cost Of Hatching Early: Vulnerability And Exposure To Predators [Poster], M. S. Palmer, B. Willink, T. Landberg, James R. Vonesh, K. M. Warkentin

Biology Presentations

Arboreal red-eyed treefrog embryos can hatch prematurely in response to egg predators. Induced early hatchlings face aquatic predators when less developed and for longer than do later hatchlings; both factors may alter survival through the high-risk early larval period. Prior work focused on developmental effects of induced hatching. In 24 h trials, less developed hatchlings were more vulnerable to three aquatic predators (shrimp, fish, water bugs) but had similar or better survival than full-term hatchlings with libellulid and aeschnid dragonfly nymphs. However, it is unknown how developmental effects and duration of exposure to predators combine to create the net effect …

Habitat Use And Population Densities Of Rain Forest Chameleons In The East Usambara Mountains Of Tanzania [Poster], Philip Shirk, David A. Patrick, James R. Vonesh, Kim Howell

Biology Presentations

Conclusions:

• Chamaeleo dilepis and Ri. brevicaudatus are absent from forest at this elevation (852-1103m), while K. matschiei, K. vosseleri, K. tenuis, and R. spinosus are relatively scarce in the forest. Trioceros deremensis and R. temporalis are common, but density varies greatly.
• The endemic and scarce K. matschiei and K. vosseleri may be of concern given their scarcity in forest habitat. Density estimates in other habitat types are needed to determine status.
• For accurate density estimates, it is important to consider seasonal variation in density and animals too high to be observed in surveys.

Tadpole Density Changes The Relationship Of Red-Eyed Treefrog Morphology And Jumping Performance [Poster], Julie Charbonnier, T. Landberg

Biology Presentations

As organisms develop, increased body size is often accompanied by shape changes that alter the morphology–performance relationship. Animals with different growth histories may also have different shapes at similar body sizes. To investigate how larval growth history affects the morphology–performance relationship, we raised red-eyed treefrog tadpoles (Agalychnis callidryas) at three densities (5, 25 and 50 tadpoles per 400 L tank) and measured jump distance during metamorphosis. We predicted that tadpoles grown at low density would metamorphose into larger frogs with relatively longer legs than those grown at higher densities. We also expected low density frogs to jump further …

Effects Of Hatching Timing On Red-Eyed Treefrog Tadpoles: Relative Vulnerability Varies Among Predators But Not With Hatchling Age-Structure, Growth Varies With The Presence Of More Vulnerable Tadpoles [Poster], B. Willink, T. Landberg, James R. Vonesh, K. M. Warkentin

Biology Presentations

In Gamboa, Panama, undisturbed red-eyed treefrog embryos typically hatch at age 6 days, but they can hatch as early as 4 days if attacked by egg predators. Early hatchlings are less developed and more vulnerable to predatory shrimp and fish. Here we assess the effect of hatching timing on risk of predation by three common insects, with different foraging styles, that prey on red-eyed treefrog larvae. Further, we examine whether the consequences of hatching early vary with the presence of later-hatched tadpoles. We induced hatching at 4 and 6 days and exposed tadpoles to giant water bugs or aeshnid or …

An Intermediate In The Evolution Of Superfast Sonic Muscles., Hin-Kiu Mok, Eric Parmentier, Kuo-Hsun Chiu, Michael L. Fine

Biology Publications

Background

Intermediate forms in the evolution of new adaptations such as transitions from water to land and the evolution of flight are often poorly understood. Similarly, the evolution of superfast sonic muscles in fishes, often considered the fastest muscles in vertebrates, has been a mystery because slow bladder movement does not generate sound. Slow muscles that stretch the swimbladder and then produce sound during recoil have recently been discovered in ophidiiform fishes. Here we describe the disturbance call (produced when fish are held) and sonic mechanism in an unrelated perciform pearl perch (Glaucosomatidae) that represents an intermediate condition in the …

Characterization Of The Expression Of Bdnf And Cgrp And Their Regulatory Pathways In Dorsal Root Ganglion During Cystitis., Sharon Yu

Theses and Dissertations

Interstitial cystitis is a chronic debilitating disease that causes pain and increased frequency of micturition, amongst other symptoms, without any identifiable cause. This disease affects a large number of the population, yet the etiology is still unknown. The present study aimed to characterize BDNF and CGRP—two neuropeptides that have both been proven to play an important role in the transmission of pain as well as in hypersensitivity. The signaling pathways regulating the expression of the two neuropeptides were also examined. Results revealed that BDNF protein expression levels increased in both L1 and L6 DRG following 48 hours post CYP-induced cystitis. …

Phosphodiesterase-5 Inhibition: A Novel Strategy To Improve Stem Cell Therapy In The Heart, Nicholas Hoke

Theses and Dissertations

Several studies have shown cellular replacement therapy as a treatment strategy of myocardial infarction but results have been limited. Therefore, enhancing the therapeutic potential of stem cells injected into ischemic microenvironments by novel preconditioning (PC) techniques is critical for improving cellular therapy. Recent studies have shown that inhibition of phosphodiesterase-5 (PDE-5) is a powerful strategy to precondition the heart and cardiomyocytes against ischemia/reperfusion injury. We therefore tested the hypothesis that inhibition of PDE-5 with sildenafil (Viagra®) or selective knockdown with a silencing vector in adipose derived stem cells (ASCs) would improve their survival after ischemia/reoxygenation in vitro and enhance cardiac …

The Characterization Of Pg0228 In Porphyromonas Gingivalis W83, Courtney Schlenker

Theses and Dissertations

Periodontitis affects 10 to 15 percent of most adult populations and can contribute to numerous systemic diseases. Porphyromonas gingivalis, a gram-negative anaerobic bacterium, is a recognized prime causative agent in periodontitis. Studies have shown a number of small non-coding RNAs (sRNAs) have been related to bacterial virulence. Many of these sRNAs require the facilitation of the bacterial Sm-like protein, Hfq, for optimum function. Hfq is a RNA chaperone involved in RNA stability, sRNA function, and polyadenylation. Mutants lacking in Hfq often show pleiotropic phenotypes, although the extent and severity of hfq null phenotypes is often species-specific. Hfq has been encoded …

Morphometric And Genetic Variation Among Populations Of The Southern Short-Tailed Shrew, Blarina Carolinensis, Located Along The Coastal Plain Of Virginia, Devon Kersten

Theses and Dissertations

The distribution of short-tailed shrews, Blarina carolinensis and B. brevicauda, demonstrates contiguous allopatry in peninsular situations in the Coastal Plain of Virginia, and in other areas. The distribution of these two species is unusual in that they do not exhibit syntopy except within a narrow corridor along the borders of their ranges. Interestingly, along the Coastal Plain of Virginia, B. carolinensis is generally found only at the distal ends of the peninsular areas, existing as local populations that appear to be isolated from each other and from the primary population that exists in south-central Virginia. It is thought that the …

Novel Role Of Mecp2 In Developing Oligodendrocytes And Myelination, Daniel Moore

Theses and Dissertations

Methyl-CpG-binding protein 2 (MeCP2 is) is an epigenetic regulator that binds to methylated DNA. Initially identified as transcriptional repressor, MeCP2 also binds to different proteins functioning as gene activator. Importantly, MecCP2 gene mutations and changes in MeCP2 levels are associated to several forms of mental retardation and autism-related disorders; including Rett, a neurodevelopmental disorder affecting primarily girls. While brain MeCP2 was considered to be exclusively neuronal, this regulator is also present in glia. We found that oligodendrocytes, the myelinating cells of the central nervous system (CNS), express particularly high MeCP2 levels at a developmental stage that precedes their final maturation. …

Determining Impediments To Gene Flow In A Natural Population Of Cornus Florida L. Cornaceae, Using Integrative Landscape Genetic Techniques, Crystal Meadows

Theses and Dissertations

This study examined the impact intervening environment has on gene flow in the insect pollinated understory tree, Cornus florida L., by combining GIS and landscape genetic techniques (Least Cost Path Analysis, Circuit Theory, and Conditional Genetic Distance). Traditional population genetic analysis indicated pair-wise relatedness was significantly correlated to distance (Pearson; r = -0.312, P < 0.001) suggesting a spatial component to offspring relatedness. Dispersal throughout the study site was non-random, exhibiting a high degree of pollen pool structure due to restricted gene flow (Two-Generation Analysis; Φft = 0.161, P = 0.001). Forest structure was quantified in GIS layers representing coniferous canopies, mixed hardwood canopies, C. florida canopies, open understory (roads), and open understory/canopy due to tree removal. Of these layers, landscape isolation for the roads layer provided the best-fit model for describing genetic differentiation among sampled pollen pools (Mantel; r = 0.542, P = 0.001). These data also suggest that improved biological inferences can be gained by examining a range of landscape isolation models.

Changes In The Expression Of Thin Filament-Associated Proteins In Colonic Smooth Muscle From Mice During Inflammation, Reem Alkahtani

Theses and Dissertations

The contractility of smooth muscle in inflammatory bowel disease and experimental colitis is reduced due to inhibition of neurotransmitter release and a decrease in the response of smooth muscle to contractile agonists. We and others have shown that inflammation induced by TNBS treatment alters the expression and/or activity of signaling molecules involved in the regulation of Ca2+ mobilization, MLC20 phosphorylation and contraction in colonic smooth muscle. Although, thin filament- associated proteins such as calponin, caldesmon, tropomyosin and smoothelin do not directly participate in contraction, they regulate acto-myosin interaction and thus, muscle contraction. Calponin, caldesmon and tropomyosin inhibit actomyosin interaction and …

A Study On The Biochemical And Cellular Effects Of Enviormental Tobacco Smoke On Adult And Developing Rat Brain Biochemistry, Brian Fuller

Theses and Dissertations

Exposure to environmental tobacco smoke (ETS) has been recognized as a significant health risk for adults and children. In adults, ETS exposure has been linked to increased incidences of cardiovascular disease and dementia. In children, exposure has been linked to behavioral and cognitive deficits. Studies on the effects of ETS in the brain have been largely epidemiological, and have lacked a defined explanation of the molecular/biochemical effects of ETS. The present dissertation aims to test whether ETS exposure leads to altered biochemistry in the adult and developing mammalian brain. A rat ETS exposure model was employed to investigate changes at …

Head-Start Juvenile And Adult Resident Eastern Box Turtles (Terrapene Carolina Carolina): Winter Ecology Including Microhabitat Selection, Temperature Tolerance And Philopatry, Amberly Moon

Theses and Dissertations

The Eastern box turtle (Terrapene carolina carolina) is one of the most common reptiles in North America, but is soon to be threatened due to increased urbanization, disease, and the pet and food trades. In order to assist resource managers in choosing suitable sites for relocation studies, more information on the winter ecology of this species is necessary. We examined the temperature tolerance, microhabitat and degree of philopatry to hibernacula for juvenile and adult E. box turtles for two consecutive winters in Charles City Co, VA. The turtles were tracked via radio telemetry to record point locations during the active …

Rate-Limiting Step Of Cone Phototransduction Recovery And Oguchi Disease Mechanisms, Frank Chen

Theses and Dissertations

ABSTRACT RATE-LIMITING STEP OF CONE PHOTOTRANSDUCTION RECOVERY AND OGUCHI DISEASE MECHANISMS By Frank Sungping Chen Advisor: Ching-Kang Jason Chen, Ph.D. Retinal photoreceptors provide the first gateway in which light information from the environment is transformed into neuronal signals. The cone and rod photoreceptors are responsible for day and night vision, respectively. Understanding rod and cone phototransduction is to figure out how these cells differ in their temporal and spatial sensitivities to allow perception of a broad dynamic range of stimuli. Phototransduction is mediated through a Gprotein signaling cascade. Light absorption by visual pigment triggers the isomerization of 11- cis-retinal covalently …

Renal Epithelial Sodium Channel (Enac) Regulation Of Pregnancy Mediated Hemodynamic Adaptations: Mechanistic Insights, Crystal West

Theses and Dissertations

Pregnancy-mediated sodium (Na) retention is required to provide an increase in plasma volume for the growing fetus. The mechanisms responsible for this Na retention are not clear. In the first study, we generated a renal tubule protein profile indicating α ENaC as the only sodium transport protein upregulated in mid and late pregnancy. To determine the in vivo activity of ENaC we conducted in vivo studies in late pregnant rats (day 18-20) and virgin rats to measure the natriuretic response to ENaC blockade (with benzamil). The in vivo activity of ENaC (UNaV post benzamil - UNaV post vehicle) was markedly …

Systemic And Microcirculatory Effects Of Hboc-201: A Hemoglobin-Based Oxygen Carrier, Bjorn Song

Theses and Dissertations

Top-loading This study compared the effects on oxygen (O2) transport of four fluids: 5.9% human serum albumin (HSA) a non-O2 carrying iso-oncotic solution (volume control);HBOC-201 (Hemopure, Biopure Corp., Cambridge, MA); MP50, HBOC-201 with a P50 of 18 mmHg; and lastly LP50, an HBOC-201 with P50 of 17 mmHg and higher viscosity (4 cP). It has been proposed that HBOC with a higher O2 affinity and a viscosity closer to that of whole blood will cause less vasoconstriction and thus a lower MAP than Hemopure (P50 = 40 mmHg and 2.2 cP). Intravital microscopic measurements were made on the spinotrapezius muscle …

Distribution And Molecular Analysis Of Avian Malaria Vectors On Four Central Virginia Prothonotary Warbler (Protonotaria Citrea) Breeding Sites, Catherine Wallace

Theses and Dissertations

Avian malaria is a devastating disease that has decimated numerous bird species. This study sought to identify the vectors of avian malaria at four central Virginia Prothonotary warbler breeding sites. Twenty one thousand mosquitoes were collected and Culex salinarius, Cx. erraticus, and Cx. pipiens/restuans were found to be the dominant species at these sites. Geographic factors, such as crop land and forest type, were determined to be potential indicators for species abundance variation between sites. Of the mosquitoes collected, ninety one (0.4%) were identified as blood fed. The blood fed mosquitoes were found to have fed on avian, mammalian, amphibian, …

A Novel Method To Detect Functional Subgraphs In Biomolecular Networks, Sterling Thomas

Theses and Dissertations

Several biomolecular pathways governing the control of cellular processes have been discovered over the last several years. Additionally, advances resulting from combining these pathways into networks have produced new insights into the complex behaviors observed in cell function assays. Unfortunately, identification of important subnetworks, or “motifs”, in these networks has been slower in development. This study focused on identifying important network motifs and their rate of occurrence in two different biomolecular networks. The two networks evaluated for this study represented both ends of the spectrum of interaction knowledge by comparing a well defined network (apoptosis) with and poorly studied network …

Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins

Theses and Dissertations

Soils, and the microbial communities contained within them, are vital for most chemical, physical, and biological processes. This study investigated how microbial community structure responded to environmental changes, such as hydrology, across vertical space (depth) and time in an emergent fresh water wetland. Research was conducted in a non-tidal freshwater wetland along the James River (Charles City County, Virginia) by establishing plots in two areas that experienced different hydrologic regimes and plant communities. Soil cores (30 cm) were collected monthly from January 2008 to February 2009, and then every two to three months thereafter until October 2009, for a total …

Network Analysis And Comparative Phylogenomics Of Micrornas And Their Respective Messenger Rna Targets Using Twelve Drosophila Species, M Ryan Woodcock

Theses and Dissertations

MicroRNAs represent a special class of small (~21–25 nucleotides) non-coding RNA molecules which exert powerful post-transcriptional control over gene expression in eukaryotes. Indeed microRNAs likely represent the most abundant class of regulators in animal gene regulatory networks. This study describes the recovery and network analyses of a suite of homologous microRNA targets recovered through two different prediction methods for whole gene regions across twelve Drosophila species. Phylogenetic criteria under an accepted tree topology were used as a reference frame to 1) make inference into microRNA-target predictions, 2) study mathematical properties of microRNA-gene regulatory networks, 3) and conduct novel phylogenetic analyses …

Genetic Evaluation Of American Shad Alosa Sapidissima Restoration Success In James River, Virginia, Aaron Aunins

Theses and Dissertations

The American shad Alosa sapidissima has experienced severe declines throughout its native range due to habitat degradation, fragmentation, and over-fishing. Hatchery supplementation is often used for stock restoration, but the effects of supplementation on population structure and genetic diversity are rarely assessed. This study employed molecular markers to evaluate how supplementation of the James River American shad population with Pamunkey River origin larvae since 1994 has impacted genetic diversity and population structure. Population genetic parameters of other major Chesapeake Bay tributaries (Susquehanna, Rappahannock, Potomac, and Nanticoke) also were characterized. Prior to stocking, the James and Pamunkey populations exhibited subtle genetic …

Adenovirus-5 Infection Affects Lipid Metabolism In Hepatic And Adipose Tissues, Marianna Sukholutsky

Theses and Dissertations

Our recent studies have shown a link between Adenovirus-5 (Ad-5) and elevated lipids, which prompted the hypothesis that Ad-5 infection might augment hepatic and/or adipose tissue lipid metabolism. To test our hypothesis, mice were infected with Ad-5 and screened for changes in lipogenesis and plasma markers associated with the metabolic syndrome. We observed increased expression of sterol regulatory element binding protein 1 (SREBP-1) in infected liver tissues, but not in adipose tissues and this correlated with elevated plasma and hepatic triglyceride levels. Elevated expression of adiponectin was seen in Ad-5 infected adipose tissues and this correlated with phosphorylated AMPK in …

The Expression Of Matrix Metalloproteinase-9 And -2 In Olfactory Injury And Recovery, Stephen Bakos

Theses and Dissertations

The olfactory system has the remarkable capacity for neurogenesis following injury. However, the molecular mechanisms important for reinnervation of the olfactory bulb (OB) remain unknown. The matrix metalloproteinases (MMPs) are important components in many central nervous system (CNS) injury paradigms, yet remain unexplored in olfactory injury and recovery. To address the role of MMPs, the temporal expressions of MMP-9 and MMP-2 were examined in 3 olfactory injury models: nerve transection (NTx), methyl bromide gas (MeBr) exposure, and nerve transection with Teflon barrier (NTx-TB). Each injury model represents a different degree of olfactory injury and neuronal recovery. In NTx, sensory axons …

The Regulation Of The Alternative Splicing Of Caspase 9, Rachel Goehe

Theses and Dissertations

The pro-apoptotic, caspase 9a, and the anti-apoptotic, caspase 9b, are derived from the caspase 9 gene by alternative splicing. This study demonstrates that the alternative splicing of caspase 9 is dysregulated in a large percentage of non-small cell lung cancer (NSCLC) tumors of the adenocarcinoma type. Furthermore, modulation of the levels of splice variants of caspase 9 had dramatic effects on the anchorage-independent growth and tumorigenic capacity of NSCLC cells. Due to these findings, the molecular mechanisms regulating the post-transcriptional processing of caspase 9 were therefore examined and an exonic splicing silencer (ESS) regulating the pre-mRNA processing of caspase 9 …