Biology Commons^™

Using The Flexon Approach To Rnai For Analysis Of Gene Function In Gonadal Development In C. Elegans, Andrew D. Spalding

Undergraduate Theses

C. elegans, a nematode worm, was used as a model organism to analyze the developmental effects of knocking down the expression of genes that are both essential to worm viability and highly enriched in reproductive tissues. In earlier research, approximately 70 C. elegans genes were identified that are both gonad-enriched and essential. To prioritize which genes should be the focus of future studies, a new strain of C. elegans was produced with three specific genetic variations that: 1) silence essential, somatic gonad-enriched gene expression, 2) limit the effects of this gene silencing to the gonad, and 3) yield a …

Fisheries Management Paper No.312: Discussion Paper On Management And Licensing Options For The Charter Industry - Statewide Strategic Review Of Western Australia’S Charter Fishing Sector, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

This consultation paper has been prepared to support the statewide strategic review of Western Australia’s (WA) charter fishing sector, which was initiated as a government commitment.

The paper details issues and proposals relating to the management and licensing framework, development opportunities and representation model for the charter fishing industry. The proposals have been developed in consultation with the Charter Review Working Group. The Department of Primary Industries and Regional Development (DPIRD) now seeks comment from relevant stakeholders on the issues and proposals outlined within this paper.

Comments provided will assist in providing advice and recommendations to the Minister for Fisheries …

The Effects Of Prenatal Cigarette Smoke Exposure On Developmental Milestones, Megan Jacobs

College of Arts & Sciences Senior Theses

In Kentucky, a reported 12.7% of mothers smoke cigarettes during pregnancy. Nicotine readily crosses the placental and blood-brain barriers, with fetal blood concentrations reaching 15% higher than maternal levels. By stimulating and desensitizing nicotinic acetylcholine receptors in the autonomic nervous system, nicotine disrupts uteroplacental blood flow, potentially altering fetal growth and development.

To investigate the effects of prenatal cigarette smoke exposure (CSE) on developmental milestones, C57Bl6 mice were exposed to either cigarette smoke (CSE, n = 30) or filtered room air (Sham, n = 20) for 3 hours daily from two days before mating until the day before birth. Offspring …

Gonadal Absence Of Ceh-22: Degradation Of Ceh-22 In The Gonads Of Caenorhabditis Elegans, Andreya C. White

Undergraduate Theses

The reproductive system of hermaphrodite Caenorhabditis elegans (C. elegans) comprises two gonadal arms, each with a terminating distal tip cell (DTC), connected by a common uterus. The DTC has two functions: leader and niche. In C. elegans, ceh-22/nkx2,5 has been found to work together with Wnt signaling to determine the fates of the DTC (Lam et al., 2006). This is an indication that ceh-22 aids in the specification of DTCs. Our research aims to determine the specific function of ceh-22 in the gonad of both male and hermaphrodite C. elegans. This will be accomplished by observing …

Editorial: The Development And Evolution Of Larval Nervous Systems, Oliver Vöcking, Allan Carrillo-Baltodano, Néva Meyer

Biology

Throughout their development, animals of various taxa go through different larval stages, which have evolved adaptations to interact with specific environments. Larval nervous systems in particular experience strong selection pressures since they control crucial physiological and behavioral processes, especially in taxa with planktotrophic larvae that need to acquire food. Selection pressures also can vary across life history stages if there are differences in factors such as habitat, predation avoidance, and diet. There is evidence for this in the relationship of the larval nervous system to the adult nervous system, which can vary widely between species. Understanding the specific adaptations of …

Two Coacting Shadow Enhancers Regulate Twin Of Eyeless Expression During Early Drosophila Development, Jacqueline Dresch, Luke L. Nourie, Regan D. Conrad, Lindsay T. Carlson, Elizabeth I. Tchantouridze, Biruck Tesfaye, Eleanor Verhagen, Mahima Gupta, Diego Borges-Rivera, Rob Drewell

Biology

The Drosophila PAX6 homolog twin of eyeless (toy) sits at the pinnacle of the genetic pathway controlling eye development, the retinal determination network. Expression of toy in the embryo is first detectable at cellular blastoderm stage 5 in an anterior–dorsal band in the presumptive procephalic neuroectoderm, which gives rise to the primordia of the visual system and brain. Although several maternal and gap transcription factors that generate positional information in the embryo have been implicated in controlling toy, the regulation of toy expression in the early embryo is currently not well characterized. In this study, we adopt an integrated experimental …

Size Matters: The Characterization Of Telomere Function In Germ Cell Development In Danio Rerio, Jessica Macneil

Graduate Doctoral Dissertations

Infertility is a growing problem worldwide. According to the WHO, 48 million couples across the globe suffer from infertility and many couples turn to Assisted Reproductive Technology (ART) to become pregnant. One readout of gamete quality and successful ART is telomere integrity because telomeres are necessary for chromosome movements during meiosis so that the segregation of chromosomes happens correctly. Telomeres are well known for their role in aging; however, they play an important and understudied role during meiosis. In meiosis, telomeres attach to the nuclear envelope (NE) via a protein chain spanning the NE that interacts with cytoplasmic motor proteins, …

Inter-Kingdom Communication And The Sympoietic Way Of Life, Scott F. Gilbert

Biology Faculty Works

Organisms are now seen as holobionts, consortia of several species that interact metabolically such that they sustain and scaffold each other’s existence and propagation. Sympoiesis, the development of the symbiotic relationships that form holobionts, is critical for our understanding the origins and maintenance of biodiversity. Rather than being the read-out of a single genome, development has been found to be sympoietic, based on multigenomic interactions between zygote-derived cells and symbiotic microbes. These symbiotic and sympoietic interactions are predicated on the ability of cells from different kingdoms of life (e.g., bacteria and animals) to communicate with one another and to have …

Connecting Genotype And Phenotype: Investigating The Functional Morphology And Molecular Architecture That Influences Craniofacial Divergence Using Lake Malawi Cichlid Fishes, Leah Delorenzo

All Dissertations

Connecting genotype and phenotype to better understand how species evolve has been a goal of evolutionary developmental biologists over the last 50 years. This dissertation aims to connect genotype and phenotype of the craniofacial skeleton within the adaptive radiation of Lake Malawi cichlids to fortify our understanding of the functional, genetic, and epigenetic factors that contribute to craniofacial divergence. I start with a functional approach using 2D geometric morphometrics to assess craniofacial shape across the Lake Malawi cichlid radiation to bolster our knowledge of the bone phenotypes that are important to niche specialization and are functionally relevant. Next, I use …

Regulation Of Embryonic Eye Regrowth In Xenopus Laevis, Dylan Guerin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Regrowth of lost organs and tissues is an amazing ability that some animals possess. For regrowth to be considered full, the organism must regrow the organ or tissue to a state that is structurally and functionally similar to that which was lost. The ability of an organism to regrow lost or damaged tissue varies among animals, both in the mechanisms utilized to achieve regrowth, and in what body parts can be regrown. Potentially even closely related species can vary wildly in regenerative ability. Therefore, regenerative research can look to other tissues and organisms for direction in elucidating the mechanisms through …

Development And Structure Of Spinal Interneuron Connectivity In Larval Zebrafish, Saul Bello Rojas

Arts & Sciences Graduate Student Theses and Dissertations

In vertebrates, spinal interneurons are essential for the initiation and propagation of locomotor activity with each class of interneurons serving its own unique role. Ipsilateral interneurons function to control locomotor speed; whereas, commissural interneurons aid in left – right alternation. To date, most studies have been aimed at studying the impact of each individual class of interneurons onto motor neurons. However, not much work has revolved around studying interneuron – interneuron connectivity among the various cardinal classes. Furthermore, it remains unknown how the connectivity of interneurons changes along their entire axonal reach. This thesis aims to address the developmental patterns …

Functional Investigation Of Shaggy, An Inhibitor Of Canonical Wnt Signaling, In The Tardigrade Hypsibius Exemplaris, Raul A. Chavarria

UNF Graduate Theses and Dissertations

Tardigrades have a highly simplified anteroposterior (AP) axis. The mechanisms that regulate the development of this secondarily simplified AP axis are not known. In many animals, the canonical Wnt (cWnt) signaling pathway regulates primary axis establishment through antagonistic interactions with inhibitors of cWnt signaling. This study investigated the roles of shaggy, an inhibitor of cWnt signaling, in regulating development in the tardigrade Hypsibius exemplaris. Gene expression patterns of shaggy and other components of the cWnt signaling pathway were analyzed alongside markers of anterior and posterior identity using Hybridization Chain Reaction in situ in H. exemplaris. RNA interference …

Effects Of Seasonal Environment On Abundance, Behavior, Visual Signaling, And Perception In Prairie Butterflies, Grace Elizabeth Hirzel

Graduate Theses and Dissertations

Phenotypic plasticity is a widespread mechanism that allows animals to respond quickly to seasonal changes in their environment. However, the depth and complexity of these plastic responses is still being discovered. One aspect of seasonal physiology that is relatively unstudied is changes to sensory physiology and how it may explain changes in behavior. To determine how changes in seasonal conditions affect behavior, coloration, and vision, I examined populations of wild butterflies in Northwest Arkansas. Focusing on a single species, the common buckeye Junonia coenia, I found that seasonal coloration covaries with thermoregulating behavior and is accompanied by changes in visual …

The Impacts Of Embryo Development And Asynchronous Hatching On Morphology, Growth, And Development Of Larval Burbot (Lota Lota)., Andrew J. Shapiro

All NMU Master's Theses

Burbot (Lota lota) are native fish in Lake Superior and typically spawn during the winter under the ice or by migrating up rivers. The early life history of larval burbot, where they dispurse, how fast they develop, and what their survival rates have not been extensively studied. Asynchronous hatching is a strategy used by other cod species as a bet-hedging strategy to ensure that some larvae are hatched in more advantageous conditions in a varying environment. Asynchronous hatching has been documented in burbot, but the extent of the period and the impacts that asynchrony has on the development of …

Phenotypic Plasticity Of Male Calls In Two Populations Of The Katydid Neoconocephalus Triops (Insecta: Tettigoniidae), Oliver M. Beckers, Teiya Kijimoto, Johannes Schul

Faculty & Staff Research and Creative Activity

The ability to respond to environmental changes plays a crucial role for coping with environmental stressors related to climate change. Substantial changes in environmental conditions can overcome developmental homeostasis, exposing cryptic genetic variation. The katydid Neoconocephalus triops is a tropical species that extended its range to the more seasonal environment of North America where it has two reproductive generations per year. The harsher winter conditions required adults to diapause which resulted in substantially different mating calls of the diapausing winter animals compared to the non-overwintering summer animals in northern Florida. The summer call corresponds to that of tropical populations, whereas …

Warmer Temperature Overrides The Effects Of Antidepressants On Amphibian Metamorphosis And Behavior, Peter Fong, Aylin Doganoglu, Eleanor Sandt, Sierra Turbeville

Biology Faculty Publications

Climate change can exacerbate the effects of environmental pollutants on aquatic organisms. Pollutants such as human antidepressants released from wastewater treatment plants have been shown to impact life-history traits of amphibians. We exposed tadpoles of the wood frog Lithobates sylvaticus to two temperatures (20°C and 25°C) and two antidepressants (fluoxetine and venlafaxine), and measured timing of metamorphosis, mass at metamorphosis, and two behaviors (startle response and percent motionless). Antidepressants significantly shortened time to metamorphosis at 20°C, but not at 25°C. At 25°C, tadpoles metamorphosed significantly faster than those at 20°C independent of antidepressant exposure. Venlafax- ine reduced body mass at …

Understanding The Environmental And Genetic Influence On Fluctuating Asymmetry And Developmental Instability In Primates, Ashly N. Romero

Graduate Theses and Dissertations

This dissertation explored the impact of environmental factors on the development and perpetuation of fluctuating asymmetry (FA) and sought to understand the role evolution may play in the FA exhibited in two primate populations: the free-ranging Cayo Santiago rhesus macaques (Macaca mulatta) and the Southwest National Primate Research Center olive baboons (Papio hamadryas anubis). Demographic, ontogenetic, secular, external, and genetic factors were examined. Specifically, this dissertation investigated FA over all ontogenetic stages, across decades, between sexes, in association with ecological catastrophes, and with tooth pathology to try and tease apart factors that may influence FA and developmental instability. This dissertation …

Southern Sea Otter (Enhydra Lutris Nereis) Fur Morphology, Thermal Function, And Buoyancy Across Ontogeny, Kate Riordan

Master's Theses

Sea otters (Enhydra lutris) have the densest fur of any animal, and the hairs function to trap a layer of air that is used for insulation. When a sea otter is born, it has a natal pelage (baby fur), and sea otters eventually molt that fur and replace it with a pelt resembling the adult fur. Sea otter fur is composed of 3 types of hairs: underhairs, intermediate hairs, and guard hairs. Sea otters are more susceptible to the negative effects of oiling from oil spills compared to other marine mammal species because they solely rely on fur …

Microglia Refine Early Multisensory Circuits In The Lateral Cortex Of The Inferior Colliculus In A Complement-Dependent Manner, Shaida Hamidi

Masters Theses, 2020-current

Microglia cells (MGCs), the resident macrophage of the brain, play a pivotal role in synaptic pruning of newly established circuits during early critical periods. Classical complement cascade signaling enables MGCs to identify unnecessary or underutilized contacts and specifically target them for removal and subsequent degradation. Such recognition and engulfment behaviors require receptor-ligand interactions, whereby “eat me” tags (complement component 3, C3) bind their cognate receptor (complement receptor 3, CR3) expressed on MGCs. Compromised complement signaling in certain systems results in under-pruning or unrefined map configurations, and is thought perhaps to underlie certain autism-related behavioral phenotypes (e.g. sensory hypersensitivities, decreased social …

Notes On Lung Development In South African Ghost Frogs (Anura: Heleophrynidae), Jackson R. Phillips, Jens Reissig, Gary Kyle Nicolau

Biology Student Research

Lungs are a prototypical trait of most tetrapods, but some amphibians have become secondarily lungless over evolutionary time. Anuran (frog) tadpoles offer an opportunity to examine lung loss from an evolutionary perspective, because there are many independent instances where lungs are not inflated until adulthood, and so are functionally lost. Lung loss is typically associated with living in fast-flowing streams, and so we examined larval lung development in the stream specialist family Heleophrynidae. We find that one genus, Hadromophryne Van Dijk, 2008, has large lungs as tadpole, while the other genus, Heleophryne Sclater, 1898, has much smaller, stunted lung buds. …

Developmental Consequences Of Hatching Asynchrony In Boat-Tailed Grackles (Quiscalus Major), Emily Radner

Scripps Senior Theses

Boat-tailed grackles (Quiscalus major) typically lay clutches of three eggs and begin incubation before the clutch is complete, resulting in hatching asynchrony. To study the developmental consequences of hatching asynchrony on boat-tailed grackles, data loggers measured nest temperatures and were compared to ambient temperatures to see when incubation began, and it appeared to begin after the second egg is laid. The third laid egg had a significantly shorter lay to pip time and lay to hatch time than the first laid egg, highlighting the need to investigate the consequences of a shortened incubation time on development. To do …

Teratogenic Effects Of Cannabinoid And Serotonin Receptor Disruption On Neural Crest Development, Brian K. Wells

Biology Theses

Neurotransmitters are well-studied in adults and have often been the focus of many treatments for both physical and psychological ailments. This thesis explores the teratogenicity of altering the activity at the serotonin 2B and 2C receptors (5-HT2B; 5-HT2C) and the cannabinoid 1 receptor (CB1R) in the serotonergic and endocannabinoid systems, respectively. This investigation is focused on neural crest derivative structures. Chapter 1 reviews the background information behind cardiac and cranial neural crest cells and overviews the serotonergic and endocannabinoid systems. In Chapter 2, using a pharmacological agent, 1-methylpsilocin (1-MP), we disrupt the activity of 5-HT2B and 5-HT2C in the early …

Activational Vs. Organizational Effects Of Sex Steroids And Their Role In The Evolution Of Reproductive Behavior: Looking To Foot-Flagging Frogs And Beyond, Nigel K. Anderson, Sarah E. Goodwin, Eric R. Schuppe, Allexandrya Dawn, Doris Preininger, Lisa A. Mangiamele, Matthew J. Fuxjager

Biological Sciences: Faculty Publications

Sex steroids play an important role in regulation of the vertebrate reproductive phenotype. This is because sex steroids not only activate sexual behaviors that mediate copulation, courtship, and aggression, but they also help guide the development of neural and muscular systems that underlie these traits. Many biologists have therefore described the effects of sex steroid action on reproductive behavior as both “activational” and “organizational,” respectively. Here, we focus on these phenomena from an evolutionary standpoint, highlighting that we know relatively little about the way that organizational effects evolve in the natural world to support the adaptation and diversification of reproductive …

Understanding The Effects Of Embryonic Hyperglycemia On Retinal Development And Maintenance, Kayla Titialii-Torres

Theses and Dissertations--Biology

Hundreds of millions of people are affected by diabetes worldwide. Whether they are diagnosed with prediabetes or Type I or II diabetes, there are a variety of mechanisms in the pathogenesis of diabetes. Diabetes is a disease which consists of recurring states of hyperglycemia that can be difficult to manage due to either lack of insulin production or improper utilization of insulin. While these mechanisms of action differ, complications induced by diabetes occur in both poorly regulated Type I and II. Common complications of diabetes include nerve damage, kidney damage, and eye damage. Eye damage specifically is called diabetic retinopathy …

Linking Ecomechanical Models And Functional Traits To Understand Phenotypic Diversity, T. E. Higham, L. A. Ferry, L. Schmitz, D. J. Irschick, S. Starko, P. S L Anderson, P. J. Bergmann, H. A. Jamniczky, L. R. Monteiro, D. Navon, J. Messier, E. Carrington, S. C. Farina, K. L. Feilich, L. P. Hernandez, Michele A. Johnson, S. M. Kawano, C. J. Law, S. J. Longo, C. H. Martin, P. T. Martone, A. Rico-Guevara, S. E. Santana, K. J. Niklas

Biology Faculty Research

Physical principles and laws determine the set of possible organismal phenotypes. Constraints arising from development, the environment, and evolutionary history then yield workable, integrated phenotypes. We propose a theoretical and practical framework that considers the role of changing environments. This 'ecomechanical approach' integrates functional organismal traits with the ecological variables. This approach informs our ability to predict species shifts in survival and distribution and provides critical insights into phenotypic diversity. We outline how to use the ecomechanical paradigm using drag-induced bending in trees as an example. Our approach can be incorporated into existing research and help build interdisciplinary bridges. Finally, …

Linking Ecomechanical Models And Functional Traits To Understand Phenotypic Diversity, Timothy E. Higham, Lara A. Ferry, Lars Schmitz, Duncan J. Irschick, Samuel Starko, Philip S.L. Anderson, Philip J. Bergmann, Heather A. Jamniczky, Leandro R. Monteiro, Dina Navon, Julie Messier, Emily Carrington, Stacy C. Farina, Kara L. Feilich, L. Patricia Hernandez, Michele A. Johnson, Sandy M. Kawano, Chris J. Law, Sarah J. Longo, Christopher H. Martin, Patrick T. Martone, Alejandro Rico-Guevara, Sharlene E. Santana, Karl J. Niklas

Biology

Physical principles and laws determine the set of possible organismal phenotypes. Constraints arising from development, the environment, and evolutionary history then yield workable, integrated phenotypes. We propose a theoretical and practical framework that considers the role of changing environments. This ‘ecomechanical approach’ integrates functional organismal traits with the ecological variables. This approach informs our ability to predict species shifts in survival and distribution and provides critical insights into phenotypic diversity. We outline how to use the ecomechanical paradigm using drag-induced bending in trees as an example. Our approach can be incorporated into existing research and help build interdisciplinary bridges. Finally, …

Vestibulospinal Circuit In The Larval Zebrafish, Zhikai Liu

Arts & Sciences Graduate Student Theses and Dissertations

The vestibular system sense gravity and self-motion to help animals maintain body balance. Although vestibular signals inform the brain of the directions and speed of our body movements, it still remains unclear how these sensory information are processed and organized in the central nervous system. My thesis aims to illustrate neural computation underlying central vestibular tuning and the topographic organization of the vestibular circuits. First I established a novel approach to perform whole-cell recording of synaptic inputs in vivo during multi-axis movements in the central vestibular neurons. This technical advance allowed me to simultaneously measure presynaptic and postsynaptic tuning, along …

Functional Optical Imaging Of The Developing Mouse Cortex In Health And Disease, Rachel Marlene Rahn

Arts & Sciences Graduate Student Theses and Dissertations

Neurodevelopmental disorders (NDDs) are a heterogeneous family of disorders characterized by the presence of abnormal developmental trajectories. Functional connectivity (FC) neuroimaging provides a minimally-invasive method by which to investigate the progression of these disorders and identify potential biomarkers of disease-related dysfunction for use in therapeutics’ development. My thesis work therefore took several approaches to the question of how the functional connectome reflects developmental change as well as system-wide perturbations from environmental or genetic factors. I explored the use of optical fluorescence and intrinsic signal imaging to characterize FC and stimulation-derived responses in a NDD model of perinatal exposure to selective …

The Origins & Functional Effects Of Postzygotic Mutations Throughout The Human Lifespan, Nicole Briana Rockweiler

Arts & Sciences Graduate Student Theses and Dissertations

Mosaicism is pervasive in humans and yet we understand little of its causes and functional consequences across the lifespan. To help solve these mysteries, we developed a suite of tools, called Lachesis, to analyze postzygotic mutations (PZMs). LachesisDetect is a novel and accurate method to detect PZMs with VAFs as low as 0.04% from bulk RNA-seq samples. LachesisMap is an innovative supervised method to reconstruct postzygotic mutation phylogenies from putative prenatal PZMs. We applied Lachesis to 17,382 samples derived from 948 donors across 54 diverse tissues and cell types from the NIH’s Genotype-Tissue Expression (GTEx) project to produce the most …

Evolution And Development Of Staminodes In Paronychia (Caryophyllaceae), Andrea D. Appleton

Honors College Theses

Staminodes are infertile stamens that have evolved numerous times in flowering plants and exhibit a vast array of forms and functions. Variation in staminodes suggests that numerous evolutionary processes underlie their origins, but to understand their how and why they evolved, comparative studies are needed in groups of closely related species. Identifying structures as staminodes is not always straightforward and sometimes requires corroborating phylogenetic and developmental evidence. Staminodial structures in Paronychia (Caryophyllaceae), for example, vary in shape and size and have been referred to as both petals and staminodes, rendering their homology uncertain. The development of staminodes was compared across …