Organismal Biological Physiology Commons^™

Marine Heatwaves And Fish Reproduction: Endocrine Responses In The Eurythermal Sheepshead Minnow (Cyprinodon Variegatus), Isabel Villafuerte

Master's Theses

Marine heatwaves associated with climate change are increasing in frequency and severity, posing significant threats to fish populations in shallow habitats such as estuaries and salt marshes. Because temperature is a primary regulator of fish reproduction, understanding how heatwaves affect reproductive physiology is critical for anticipating the biological consequences of ongoing climate change for coastal fishes. Here we examined how simulated heatwave conditions affect the reproductive hypothalamic-pituitary-gonadal (HPG) endocrine axis in the estuarine sheepshead minnow (Cyprinodon variegatus), a eurythermal fish well suited to studying thermal stress responses in estuarine environments. Adult sheepshead minnows acclimated to a daily oscillating …

Genetic Analysis Of Methionine Restriction-Associated Mitochondrial Unfolded Protein Response Signaling., Josh D. Dodge

Biology Dissertations - Archive

The lifespan of an organism is dictated by various genetic and environmental factors. One such determinant is the health of mitochondria which are organelles that mediate various critical cell functions including a significant role in generating the vast supply of cellular energy. Indeed, the gradual decline of mitochondrial function is believed to be a hallmark and possible cause of aging. Paradoxically, mild mitochondrial dysfunction early in life extends lifespan in various model organisms. Cells use diverse approaches to promote mitochondrial homeostasis, including the transcriptional reprogramming of cells by mitochondrial unfolded protein response (UPRmt) to mitigate mitochondrial stress. Consistently, UPRmt activation …

The Physiological Significance Of Nitric Oxide Synthase In Staphylococci, Ryan M. Singh

Theses & Dissertations

Staphylococci, particularly Staphylococcus epidermidis, are common causes of implant-associated infections that may result in notable morbidity and mortality. One of the ways the innate immune system attempts to combat these invading pathogens is via the respiratory burst, in which free radical species such as nitric oxide (NO^•), toxic to bacterial respiration, are released in large quantities. Despite the toxicity of NO^•, some bacteria, including staphylococci, encode an endogenous bacterial nitric oxide synthase (bNOS), whose physiological role has been unclear until now. In this dissertation, we demonstrate that S. epidermidis is able to overcome the toxicity …

The Zinc Transporter Zipt-7.1 Regulates Sperm Activation In Nematodes, Yanmei Zhao, Chieh-Hsiang Tan, Amber Krauchunas, Andrea Scharf, Nicholas Dietrich, Kurt Warnhoff, Zhiheng Yuan, Marina Druzhinina, Sam Guoping Gu, Long Miao, Andrew Singson, Ronald E Ellis, Kerry Kornfeld

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Sperm activation is a fascinating example of cell differentiation, in which immotile spermatids undergo a rapid and dramatic transition to become mature, motile sperm. Because the sperm nucleus is transcriptionally silent, this transition does not involve transcriptional changes. Although Caenorhabditis elegans is a leading model for studies of sperm activation, the mechanisms by which signaling pathways induce this transformation remain poorly characterized. Here we show that a conserved transmembrane zinc transporter, ZIPT-7.1, regulates the induction of sperm activation in Caenorhabditis nematodes. The zipt-7.1 mutant hermaphrodites cannot self-fertilize, and males reproduce poorly, because mutant spermatids are defective in responding to activating …

Regulation Of The Tubulin Homolog Ftsz In Escherichia Coli, Monika S. Buczek

Dissertations, Theses, and Capstone Projects

Escherichia coli is a well-known pathogen, and importantly, a widely used model organism in all fields of biological sciences for cloning, protein purification, and as a model for Gram-negative bacterial species. And yet, researchers do not fully understand how this bacterium replicates and divides. Every year additional division proteins are discovered, which adds complexity to how we understand E. coli undergoes cell division. Due to their specific roles in cytokinesis, some of these proteins may be potential targets for development of antibacterials or bacteriostatics, which are much needed for fighting the current global antibacterial deficit. My thesis work focuses on …

Functional Analysis Of Microrna Pathway Genes In The Somatic Gonad And Germ Cells During Ovulation In C. Elegans, Carmela Rios

Dissertations (1934 -)

MicroRNAs (miRNAs) are post-­transcriptional regulators of gene expression that play critical roles in animal development and physiology, though functions for most miRNAs remain unknown. Worms with reduced miRNA biogenesis due to loss of Drosha or Pasha/DGCR8 activity are sterile and fail to ovulate, indicating that miRNAs are required for the process of oocyte maturation and ovulation. Starting with this penetrant sterile phenotype and using new strains created to perform tissue-­specific RNAi, we characterize the roles of the C. elegans Pasha, pash-­1, and two miRNA-­specific Argonautes, alg-­1 and alg-­2, in somatic gonad cells and in germ cells in the regulation of …

A Phylogenetic Analysis Of Dictyostelium Purpureum Based On Nuclear Rdna Sequences, Mahmoud Suliman

Graduate Theses and Dissertations

Dictyostelids (cellular slime molds) are eukaryotic microorganisms that have both unicellular and multicellular stages during their life cycle. In this study, a molecular phylogenetic analysis was conducted for isolates of one species (Dictyostelium purpureum) based DNA sequences of the ITS, 5.8S and SSU regions of nuclear rDNA. Moreover, a detailed morphological study was carried out using images obtained with both dissecting and compound microscopes. Mating experiments were carried out to assess macrocysts formation between each pair of isolates. The constructed molecular phylogenetic trees indicate that (1) D. purpureum isolates are more closely related to each other than to other species …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Dorsal Eye Selector Pannier (Pnr) Suppresses The Eye Fate To Define Dorsal Margin Of The Drosophila Eye, Sarah M. Oros, Meghana Tare, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Axial patterning is crucial for organogenesis. During Drosophila eye development, dorso-ventral (DV) axis determination is the first lineage restriction event. The eye primordium begins with a default ventral fate, on which the dorsal eye fate is established by expression of the GATA-1 transcription factor pannier (pnr). Earlier, it was suggested that loss of pnr function induces enlargement in the dorsal eye due to ectopic equator formation. Interestingly, we found that in addition to regulating DV patterning, pnr suppresses the eye fate by downregulating the core retinal determination genes eyes absent (eya), sine oculis (so) and dacshund (dac) to define the …

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.