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Title: Expression of autophagy transcripts and proteins in the ocular lens suggests a role for autophagy in lens cell and cellular differentiation.
Creator: Mattucci, Lyndzie., Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: The lens is an avascular organ that focuses light onto the retina where neural signals are transmitted to the brain and translated into images. Lens transparency is vital for maintaining function. The lens is formed through a transition from organelle-rich epithelial cells to organelle-free fiber cells. Lens cell differentiation, leading to the lack of organelles, provides an environment optimal for minimizing light scatter and maximizing the ability to focus light onto the retina. The...
Show moreThe lens is an avascular organ that focuses light onto the retina where neural signals are transmitted to the brain and translated into images. Lens transparency is vital for maintaining function. The lens is formed through a transition from organelle-rich epithelial cells to organelle-free fiber cells. Lens cell differentiation, leading to the lack of organelles, provides an environment optimal for minimizing light scatter and maximizing the ability to focus light onto the retina. The process responsible for orchestrating lens cell differentiation has yet to be elucidated. In recent years, data has emerged that led our lab to hypothesize that autophagy is likely involved in lens cell maintenance, cell differentiation, and maintenance of lens transparency. As a first step towards testing this hypothesis, we used RT-PCR, western blot analysis, immunohistochemistry, confocal microscopy, and next generation RNA-Sequencing (RNA-Seq) to examine autophagy genes expressed by the lens to begin mapping their lens function.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3360958
Subject Headings: Cell differentiation, Protein binding, Research, Cellular control mechanisms, Apoptosis
Format: Document (PDF)

Title: Regulation of growth by TGF-B in Drosophila.
Creator: Gesualdi, Scott C., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Key to our understanding of growth regulation in Drosophila would be discovering a ligand that could regulate steroid synthesis. Activins are involved in regulating steroid hormone release in vertebrates. In invertebrates, they most likely function to keep ecdysone levels low to allow the larvae more time to achieve critical weight in order to initiate the metamorphic process. TGF-B(Transforming Growth Factor Beta) is a family of cytokine growth factors. We find that two members of the TGF-B...
Show moreKey to our understanding of growth regulation in Drosophila would be discovering a ligand that could regulate steroid synthesis. Activins are involved in regulating steroid hormone release in vertebrates. In invertebrates, they most likely function to keep ecdysone levels low to allow the larvae more time to achieve critical weight in order to initiate the metamorphic process. TGF-B(Transforming Growth Factor Beta) is a family of cytokine growth factors. We find that two members of the TGF-B signaling pathway Drosophila Activin (dACT) and Activin-like ligand Dawdle (DAW) signal through the type I receptor Baboon (BABO) and the type II receptor PUNT to primarily activate the transcription factor dSMAD2 and MAD to a lesser extent. One transcription factor brinker (brk) appears to be central to dACT signaling., In wings dACT signaling is necessary to promote growth however, dACT is not expressed in wings suggesting that dACT is provided through the endocrine system. One possible target tissue of dACT signaling is the ring gland (RG), which synthesizes and secretes the steroid hormone ecdysone (E). Consistent with this idea, using the UAS/GAL-4 system, we find that over-expression of the TGF-B ligand dACT with the neuroendocrine driver 386Y-GAL4 results in an increase in the size of flies. Surprisingly, when we increase the dose with two copies of dACT, it decreases the size of flies also indicating non-autononomous effects. We find that overexpression of the activated form of the dACT type I receptor Baboon (BABO) or brk with the ring gland specific driver phm-GAL4 results in developmental arrest of larvae that stay small and never pupate. The developmental arrest can be overcome by feeding larvae E, suggesting that dACT represses E through brk. These results suggest a model where dACT signaling activates brk which inhibits E. We picked three cytochrome P450 enzymes: phantom (PHM), disembodied (DIS) and spookier (SPKR)., PHM is not regulated by any component in the dACT signaling pathway however, we find DIS and SPKR are down-regulated through brk. MAD and dSmad2 bind to a Smad binding site and MAD out-competes dSMAD2. We find no evidence that Drosophila insulin-like peptides (DILPS)/PI3- Kinase or Ras signal through the dActivin signaling pathway.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/228773
Subject Headings: Cell differentiation, Developmental genetics, Integrins, Cellular control mechanisms
Format: Document (PDF)

Title: Potential therapies and neuroprotective cascades in anoxia tolerant freshwater turtle Trachemys scripta ellegans.
Creator: Nayak, Gauri., Charles E. Schmidt College of Science, Department of Biomedical Science
Abstract/Description: Mammalian neurons exhibit extreme sensitivity to oxygen deprivation and undergo rapid and irreversible degeneration when oxygen supply is curtailed. Though several neuroprotective pathways are activated during oxygen deprivation, their analyses are masked by the complex series of pathological events which are triggered simultaneously. Such events can be analyzed in the anoxia tolerant fresh water turtle, which can inherently survive the conditions of oxygen deprivation and post-anoxic...
Show moreMammalian neurons exhibit extreme sensitivity to oxygen deprivation and undergo rapid and irreversible degeneration when oxygen supply is curtailed. Though several neuroprotective pathways are activated during oxygen deprivation, their analyses are masked by the complex series of pathological events which are triggered simultaneously. Such events can be analyzed in the anoxia tolerant fresh water turtle, which can inherently survive the conditions of oxygen deprivation and post-anoxic reoxygenation without brain damage. It is likely in such a model that modulation of a particular molecular pathway is adaptive rather than pathological. The major objective behind this study was to analyze the intracellular signaling pathways mediating the protective effects of adenosine, a potential neuromodulator, and its effect on cell survival by influencing the key prosurvival proteins that prevent apoptosis. In vivo and in vitro studies have shown that adenosine acts as a neuroprotective metabolite and its action can be duplicated or abrogated using specific agonist and antagonists. Stimulating the adenosine receptors using selective A1 receptor agonist N6-cyclopentyladenosine (CPA) activated the presumed prosurvival ERK and P13-K/AKT cascade promoting cell survival, and suppression of the receptor using the selective antagonist DPCPX (8- cyclopentyl-1,3-dipropylxanthine) activated the prodeath JNK and P38 pathways. The complex regulation of the MAPK's/AKT signaling cascades was also analyzed using their specific inhibitors. The inhibiton of the ERK and AKT pathway increased cell death, indicating a prosurvival role, whereas inhibiton of the JNK and p38 pathway increased cell survival in this model. In vitro studies have also shown a high Bcl-2/BAX ratio during anoxia and reoxygenation, indicating a strong resistance to cell death via apoptosis., Silencing of the anti-apoptotic Bcl-2 gene using specific siRNA upregulated levels of prodeath BAX, thus altering the Bcl-2/BAX ratio and elevating cleaved Caspase-3 levels leading to increased cell death. Another promising neuroprotective target which we analyzed was Neuroglobin, which was induced during oxygen crisis and silencing this gene indicated that its plays a major role in modulation of ROS. This study strongly emphasizes the advantages of an alternate animal model in elucidating neuroprotective mechanisms and revealing novel therapeutic targets which could eventually help clinicians to design new stroke therapies based on naturally tolerant organisms.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/186762
Subject Headings: Turtles, Physiology, Adenosine, Receptors, Cellular signal transduction, Molecular neurobiology, Apoptosis, Research, Cellular control mechanisms
Format: Document (PDF)

Title: An investigation of the role of PAK6 tumorigenesis.
Creator: Roberts, JoAnn, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: The function and role of PAK6, serine/threonone kinase, in cancer progressionhas not yet been clearly identified. Several studies reveal that PAK6 may participate in key changes contributing to cancer progression such as cell survival, cell motility, and invasiveness. Basedon the membrane localization of PAK6 in prostate and breast cancer cells,we speculated that PAK6 plays a rolein cancer progression cells by localizing on the membrane and modifying proteins linked to motility and...
Show moreThe function and role of PAK6, serine/threonone kinase, in cancer progressionhas not yet been clearly identified. Several studies reveal that PAK6 may participate in key changes contributing to cancer progression such as cell survival, cell motility, and invasiveness. Basedon the membrane localization of PAK6 in prostate and breast cancer cells,we speculated that PAK6 plays a rolein cancer progression cells by localizing on the membrane and modifying proteins linked to motility and proliferation. We isolated the raft domain of breast cancer cells expressing either wild type (WT), constitutively active (SN), or kinase dead PAK6 (KM) and found that PAK6 is a membrane associated kinase which translocates from the plasma membrane to the cytosol when activated. The downstream effects of PAK6 are unknown ; however, results from cell proliferation assays suggest a growth regulatory mechanism.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3356888
Subject Headings: Apoptosis, Cancer, Etiology, Cancer cells, Proliferation, Cellular signal transduction, Cellular control mechanisms, Cell cycle, Regulation
Format: Document (PDF)

Title: Synaptic Rearrangements and the Role of Netrin-Frazzled Signaling in Shaping the Drosophila Giant Fiber Circuit.
Creator: Lloyd, Brandon N., Murphey, Rodney K., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: In the developing CNS, presynaptic neurons often have exuberant overgrowth and form excess (and overlapping) postsynaptic connections. Importantly, these excess connections are refined during circuit maturation so that only the appropriate connections remain. This synaptic rearrangement phenomenon has been studied extensively in vertebrates but many of those models involve complex neuronal circuits with multiple presynaptic inputs and postsynaptic outputs. Using a simple escape circuit in...
Show moreIn the developing CNS, presynaptic neurons often have exuberant overgrowth and form excess (and overlapping) postsynaptic connections. Importantly, these excess connections are refined during circuit maturation so that only the appropriate connections remain. This synaptic rearrangement phenomenon has been studied extensively in vertebrates but many of those models involve complex neuronal circuits with multiple presynaptic inputs and postsynaptic outputs. Using a simple escape circuit in Drosophila melanogaster (the giant fiber circuit), we developed tools that enabled us to study the molecular development of this circuit; which consists of a bilaterally symmetrical pair of presynaptic interneurons and postsynaptic motorneurons. In the adult circuit, each presynaptic interneuron (giant fiber) forms a single connection with the ipsilateral, postsynaptic motorneuron (TTMn). Using new tools that we developed we labeled both giant fibers throughout their development and saw that these neurons overgrew their targets and formed overlapping connections. As the circuit matured, giant fibers pruned their terminals and refined their connectivity such that only a single postsynaptic connection remained with the ipsilateral target. Furthermore, if we ablated one of the two giant fibers during development in wildtype animals, the remaining giant fiber often retained excess connections with the contralateral target that persisted into adulthood. After demonstrating that the giant fiber circuit was suitable to study synaptic rearrangement, we investigated two proteins that might mediate this process. First, we were able to prevent giant fibers from refining their connectivity by knocking out highwire, a ubiquitin ligase that prevented pruning. Second, we investigated whether overexpressing Netrin (or Frazzled), part of a canonical axon guidance system, would affect the refinement of giant fiber connectivity. We found that overexpressing Netrin (or Frazzled) pre- & postsynaptically resulted in some giant fibers forming or retaining excess connections, while exclusively presynaptic (or postsynaptic) expression of either protein had no effect. We further showed that by simultaneously reducing (Slit-Robo) midline repulsion and elevating Netrin (or Frazzled) pre- & postsynaptically, we significantly enhanced the proportion of giant fibers that formed excess connections. Our findings suggest that Netrin-Frazzled and Slit-Robo signaling play a significant role in refining synaptic circuits and shaping giant fiber circuit connectivity.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004758, http://purl.flvc.org/fau/fd/FA00004758
Subject Headings: Drosophila melanogaster--Cytogenetics., Genetic transcription., Transcription factors., Cellular signal transduction., Cellular control mechanisms., Cell receptors.
Format: Document (PDF)

Title: Representation of object-in-context within mouse hippocampal neuronal activity.
Creator: Asgeirsdottir, Herborg Nanna, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: The rodent hippocampus is critical for processing spatial memory but its contribution to non-spatial, specifically object memory is debated. The cognitive map theory of hippocampal function states that the hippocampus stores relationships of goal locations (places) to discrete items (objects) encountered within environments. Dorsal CA1 place cells were recorded in male C57BL/6J mice performing three variations of the novel object recognition paradigm to define "object-in-context"...
Show moreThe rodent hippocampus is critical for processing spatial memory but its contribution to non-spatial, specifically object memory is debated. The cognitive map theory of hippocampal function states that the hippocampus stores relationships of goal locations (places) to discrete items (objects) encountered within environments. Dorsal CA1 place cells were recorded in male C57BL/6J mice performing three variations of the novel object recognition paradigm to define "object-in-context" representation of hippocampal neuronal activity that may support object memory. Results indicate, (i) that place field stability is higher when polarizing environmental cues are provided during object recognition; (ii) hippocampal place fields remain stable throughout the novel object recognition testing without a polarizing cue; and (iii) time dependent effects on stability when objects were dissociated from the context. These data indirectly support that the rodent hippocampus processes object memory, and challenge the view that "object-in-context" representations are formed when mice perform novel object recognition task.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362339
Subject Headings: Mice as laboratory animals, Hippocampus (Brain), Neurotransmitter receptors, Cellular control mechanisms, Cellular signal transduction
Format: Document (PDF)

Title: Highwire coordinates synapse formation and maturation by regulating both a map kinase cascade and the ability of the axon to respond to external cues in the giant fiber system of Drosophila Melanogaster.
Creator: Borgen, Melissa A., Murphey, Rodney K., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The ubiquitin ligase Highwire is responsible for cell-autonomously promoting synapse formation in the Drosophila Giant Fiber system. highwire mutants show defects in synaptic function and extra branching at the axon terminal, corresponding to transient branching that occur in the course of giant synapse formation during metamorphosis. The MAP kinase pathway, including Wallenda and JNK/Basket, plus the transcription factor Jun, act to suppress synaptic function and axon pruning in a dosage...
Show moreThe ubiquitin ligase Highwire is responsible for cell-autonomously promoting synapse formation in the Drosophila Giant Fiber system. highwire mutants show defects in synaptic function and extra branching at the axon terminal, corresponding to transient branching that occur in the course of giant synapse formation during metamorphosis. The MAP kinase pathway, including Wallenda and JNK/Basket, plus the transcription factor Jun, act to suppress synaptic function and axon pruning in a dosage sensitive manner, suggesting different molecular mechanisms downstream of the MAP kinase pathway govern function and pruning. A novel role for Highwire is revealed, regulating the giant fiber axon’s ability to respond to external cues regulated by Fos. When expression of the transcription factor Fos is disrupted in the post-synaptic TTMn or surrounding midline glia of highwire mutants, the giant fiber axons show a marked increase in axon overgrowth and midline crossing. However, synaptic function is rescued by the cell nonautonomous manipulation of Fos, indicating distinct mechanisms downstream of Highwire regulating synaptic function and axon morphology.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004081, http://purl.flvc.org/fau/fd/FA00004081
Subject Headings: Cell differentiation, Cellular control mechanisms, Cellular signal transduction, Drosophila melanogaster -- Cytogenetics, Gene expression, Genetic transcription
Format: Document (PDF)

Title: Netrin-Frazzled signaling instructs synaptogenesis and plasticity at an identified central synapse in Drosophila.
Creator: Orr, Brian, Murphey, Rodney K., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The classic guidance molecules, Netrin and its receptor Frazzled (Fra), dictate the strength of synaptic connections in the giant fiber system (GFS) of Drosophila melanogaster by regulating gap junction localization in the pre-synaptic terminal. In Netrin mutant animals the synaptic coupling between a giant interneuron and the jump motor neuron was weakened. Dye-coupling between these two neurons was severely compromised or absent. These mutants exhibited anatomically and physiologically...
Show moreThe classic guidance molecules, Netrin and its receptor Frazzled (Fra), dictate the strength of synaptic connections in the giant fiber system (GFS) of Drosophila melanogaster by regulating gap junction localization in the pre-synaptic terminal. In Netrin mutant animals the synaptic coupling between a giant interneuron and the jump motor neuron was weakened. Dye-coupling between these two neurons was severely compromised or absent. These mutants exhibited anatomically and physiologically defective synapses between the giant fiber (GF) and tergotrochanteral motor neuron (TTMn). In cases where Netrin mutants displayed apparently normal synaptic anatomy, half of the specimens exhibited physiologically defective synapses. Dye-coupling between the giant fiber and the motor neuron was reduced or eliminated, suggesting that gap junctions were disrupted in the Netrin mutants. When we examined the gap junctions with antibodies to Shaking-B Innexin (ShakB), they were significantly decreased or absent in the pre-synaptic terminal of the mutant GF. This data is the first to show that Netrin and Frazzled regulate placement of gap junctions pre-synaptically at a central synapse. In the Drosophila Giant Fiber System, we demonstrate a mechanism that ensures the monoinnervation of two homologous motor neurons by two homologous interneurons. In a scenario where both interneurons could synapse with both motor neuron targets, each interneuron exclusively synapsed with only one target and the circuit functions at normal physiological levels. This innervation pattern depended on the ratio of netrin-to-frazzled expression. When Netrin was over expressed in the system, shifting the ratio in favor of Netrin, both interneurons synapsed with both target motor neurons and physiological function was reduced. This resulted in the polyinnervationof a single target. In contrast, when Frazzled was over expressed in the system, one interneuron innervated both targets and excluded the remaining interneuron from making any synaptic contact. This resulted in a single interneuron mono-innervating both motor neurons and physiological function was mutant. The orphaned interneuron made no synaptic contact with either motor neuron target. Physiological function was only normal when the Netrin-Frazzled ratio was at endogenous levels and each GF monoinnervated one motor neuron. When we examined the gap junctions at this synapse in experimental animals, there was a significant reduction of gap junction hemichannels in the presynaptic terminal of axons that deviated from normal innervation patterns. While the synapse dyecoupled, the reduction in gap junction hemichannels reduced function in the circuit.
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Date Issued: 2013
PURL: http://purl.flvc.org/fau/fd/FA0004041
Subject Headings: Cellular control mechanisms, Cellular signal transduction, Drosophila melanogaster -- Cytogenetics, Genetic transcription, Transcription factors
Format: Document (PDF)

Title: Highwire's characterization and signaling roles in Drosophila central synapse formation.
Creator: Rowland, Kimberly Diane., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The assembly and maintenance of central synapses is a complex process, requiring myriad genes and their products. Highwire is a large gene containing a RING domain, characteristic of ubiquitin E3 ligases. Highwire has been shown to restrain axon growth and control synaptogenesis at a peripheral synapse. Here I examine the roles of Highwire at a central synapse in the adult Drosophila Giant Fiber System (GFS). Highwire is indeed necessary for proper axonal growth as well as synaptic...
Show moreThe assembly and maintenance of central synapses is a complex process, requiring myriad genes and their products. Highwire is a large gene containing a RING domain, characteristic of ubiquitin E3 ligases. Highwire has been shown to restrain axon growth and control synaptogenesis at a peripheral synapse. Here I examine the roles of Highwire at a central synapse in the adult Drosophila Giant Fiber System (GFS). Highwire is indeed necessary for proper axonal growth as well as synaptic transmission in the GFS. Differences arise between the central synapse and the neuromuscular junction (NMJ), where highwire was initially characterized : expresion from the postsynaptic cell can rescue highwire synaptic defects, which is not seen at the NMJ. In addition, a MAP kinase signaling pathway regulated by highwire at the NMJ has differing roles at a central synapse. Wallenda MAPK can rescue not only the highwire anatomical phenotype but also the defects seen in transmission. Another distinction is seen here : loss of function basket and Dfos enhance the highwire anatomical phenotype while expression of dominant negative basket and Dfos suppress the highwire phenotype. As a result we have compared the signaling pathway in flies and worms and found that the NMJ in the two organisms use a parallel pathway while the central synapse uses a distinct pathway.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352826
Subject Headings: Cellular control mechanisms, Cellular signal transduction, Cell differentiation, Gene expression, Genetic transcription, Transcription factors, Drosophila melanogaster, Cytogenetics
Format: Document (PDF)

Title: Analyses of neuronal replacement in the neuron-depleted olfactory systems in adult mice.
Creator: Liu, Huan, Charles E. Schmidt College of Medicine
Abstract/Description: New neurons are continuously generated in the olfactory system of adult mice, including olfactory sensory neurons (OSNs) in the olfactory epithelium (OE) and interneurons, produced in the subventricular zone (SVZ) and migrated toward olfactory bulb (OB) along rostral migratory stream (RMS). The present study observed the effects of target neuron loss on the life-span and maturation of adult-born OSNs in the OE and on the proliferation, migration and differentiation of SVZ stem cells in the...
Show moreNew neurons are continuously generated in the olfactory system of adult mice, including olfactory sensory neurons (OSNs) in the olfactory epithelium (OE) and interneurons, produced in the subventricular zone (SVZ) and migrated toward olfactory bulb (OB) along rostral migratory stream (RMS). The present study observed the effects of target neuron loss on the life-span and maturation of adult-born OSNs in the OE and on the proliferation, migration and differentiation of SVZ stem cells in the forebrain after eliminating bulb neurons. We found the life-span of newborn neurons in the absence of synaptic targets was shortened, but the timing of maturation was not delayed. In addition, SVZ cells continued to divide and migrate to the damaged bulb, and the migration of newborn cells in the RMS on the contralateral side was delayed at 2 weeks post-BrdU. Also, the proliferation of cells in dentate gyrus of the hippocampus was not affected by OB damage at 3 weeks post-lesion, though lesion affects occurred in the adult SVZ/RMS.
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Date Issued: 2008
PURL: http://purl.flvc.org/fcla/dt/172671
Subject Headings: Mice as laboratory animals, Neurotransmitter receptors, Sensory neurons, Testing, Cellular control mechanisms
Format: Document (PDF)

Title: Integrin αVβ5-mediated Removal Of Apoptotic Cell Debris By The Eye Lens And Its Inhibition By UV-light Exposure.
Creator: Bakina, Olga, Kantorow, Marc, Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: The lens is a crystallin tissue of the anterior part of the eye that focuses light onto the retina. Aged-related cataract, which is the result of loss of lens transparency, is the most common cause of blindness in the world. Being constantly exposed to UV-light, lens is significantly affected by its UVA spectrum. UV-light exposure has been shown to result in apoptosis of lens cells which can lead to cataract formation. This suggests the need for molecular mechanisms to remove apoptotic debris...
Show moreThe lens is a crystallin tissue of the anterior part of the eye that focuses light onto the retina. Aged-related cataract, which is the result of loss of lens transparency, is the most common cause of blindness in the world. Being constantly exposed to UV-light, lens is significantly affected by its UVA spectrum. UV-light exposure has been shown to result in apoptosis of lens cells which can lead to cataract formation. This suggests the need for molecular mechanisms to remove apoptotic debris from the lens. In the set of experiments it was proven that integrin αvβ5-mediated pathway is involved in phagocytosis of apoptotic cell debris in the ocular lens, thus contributing to its homeostasis. Additionally, it was shown that exposure to UV-light plays role in cataract formation by influencing integrin αvβ5-mediated phagocytosis function.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004568
Subject Headings: Eye x Diseases--Research., Retinal degeneration., Cellular control mechanisms., Apoptosis
Format: Document (PDF)

Title: Selective Activation of the SK1 Subtype of Small Conductance Ca2+ Activated K+ Channels by GW542573X in C57BL6J Mice Impairs Hippocampal-dependent Memory.
Creator: Rice Kuchera, Claire A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: SK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal...
Show moreSK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal-dependent object memory, contextual and cued conditioning, and trace fear conditioning was examined. The results demonstrated that pre- but not post-training systemic administration of GW542573X impaired object memory and trace fear memory in mice 24 h after training. Contextual and cued fear memory were not disrupted. These current data suggest that activation of SK1 subtype-containing SK channels impairs long-term memory. These results are consistent with converging evidence that SK channel activation suppressed behaviorally triggered synaptic plasticity necessary for encoding hippocampal-dependent memory.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004541, http://purl.flvc.org/fau/fd/FA00004541
Subject Headings: Cellular control mechanisms, Cognitive neuroscience, Cognitive psychology, Hippocampus (Brain), Mice as laboratory animals, Neurotransmitter receptors
Format: Document (PDF)

Title: Characterization of RNase in Mycoplasma genitalium and study of its possible role in tRNA processing.
Creator: Lalonde, Maureen S., Florida Atlantic University, Li, Zhongwei, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: Exoribonucleases degrade RNA and are important in RNA metabolism and gene expression. Mycoplasma genitalium, a bacterium with the smallest genome known, has only one identified exoribonuclease, RNase R (MgR). In this work RNA degradation properties of purified MgR were examined. As observed in Escherichia coli RNase R (EcR) studies, MgR degrades poly(A), rRNA, and oligoribonucleotides in 3'--->5' direction, though its substrate specificity and optimal activity requirements vary. Interestingly...
Show moreExoribonucleases degrade RNA and are important in RNA metabolism and gene expression. Mycoplasma genitalium, a bacterium with the smallest genome known, has only one identified exoribonuclease, RNase R (MgR). In this work RNA degradation properties of purified MgR were examined. As observed in Escherichia coli RNase R (EcR) studies, MgR degrades poly(A), rRNA, and oligoribonucleotides in 3'--->5' direction, though its substrate specificity and optimal activity requirements vary. Interestingly, MgR is sensitive to 2-O-methylation stopping downstream of such modifications in native rRNA and synthetic oligoribonucleotides. MgR removes the 3' trailer sequence from a tRNA precursor of M. genitalium and generates products equal to the mature tRNA, demonstrating a role of MgR in tRNA maturation. The 3' terminal CCA sequence and the acceptor stem of tRNA play a role in determining the formation of such products by MgR. These results suggest multiple functions of RNase R in RNA metabolism in Mycoplasma.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13317
Subject Headings: Gene expression, RNA-protein interactions, Cellular control mechanisms, Ribonucleases--Analysis, Cell membranes
Format: Document (PDF)

Title: Developmental and Protective Mechanisms of the Ocular Lens.
Creator: Chauss, Daniel C., Kantorow, Marc, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biomedical Science
Abstract/Description: The vertebrate eye lens functions to focus light onto the retina to produce vision. The lens is composed of an anterior monolayer of cuboidal epithelial cells that overlie a core of organelle free fiber cells. The lens develops and grows throughout life by the successive layering of lens fiber cells via their differentiation from lens epithelial cells. Lens developmental defect and damage to the lens are associated with cataract formation, an opacity of the lens that is a leading cause of...
Show moreThe vertebrate eye lens functions to focus light onto the retina to produce vision. The lens is composed of an anterior monolayer of cuboidal epithelial cells that overlie a core of organelle free fiber cells. The lens develops and grows throughout life by the successive layering of lens fiber cells via their differentiation from lens epithelial cells. Lens developmental defect and damage to the lens are associated with cataract formation, an opacity of the lens that is a leading cause of visual impairment worldwide. The only treatment to date for cataract is by surgery. Elucidating those molecules and mechanisms that regulate the development and lifelong protection of the lens is critical toward the development of future therapies to prevent or treat cataract. To determine those molecules and mechanisms that may be important for these lens requirements we employed high-throughput RNA sequencing of microdissected differentiation statespecific lens cells to identify an extensive range of transcripts encoding proteins expressed by these functionally distinct cell types. Using this data, we identified differentiation state-specific molecules that regulate mitochondrial populations between lens epithelial cells that require the maintenance of a functional population of mitochondria and lens fiber cells that must eliminate their mitochondria for their maturation. In addition, we discovered a novel mechanism for how lens epithelial cells clear apoptotic cell debris that could arise from damage to the lens and found that UVlight likely compromises this system. Moreover, the data herein provide a framework to determine novel lens cell differentiation state-specific mechanisms. Future studies are required to determine the requirements of the identified molecules and mechanisms during lens development, lens defense against damage, and cataract formation.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004577
Subject Headings: Eye--Diseases--Etiology., Cell differentiation., Cellular signal transduction., Protein folding., Mitochondrial pathology., Cellular control mechanisms., Apoptosis., Oxidative stress--Prevention.
Format: Document (PDF)

Title: Hippocampal CA1 activation during object memory encoding in the novel object recognition task.
Creator: Cinalli, David A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal...
Show moreTranscription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004436, http://purl.flvc.org/fau/fd/FA00004436
Subject Headings: Association of ideas, Cellular control mechanisms, Cellular signal transduction, Episodic memory, Hippocampus (Brain) -- Physiology, Human information processing, Mice as laboratory animals
Format: Document (PDF)

Title: Of Mice, Men and Memories: The Role of the Rodent Hippocampus in Object Recognition.
Creator: Cohen, Sarah J., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Establishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent...
Show moreEstablishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent literature was conducted, with a focus on studies that used the Novel Object Recognition (NOR) paradigm for testing. The total amount of time the objects were explored during training and the delay imposed between training and testing seemed to determine hippocampal recruitment in rodents. Male C57BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae to allow for the inactivation of the hippocampus at discrete time points in the task. The results suggest that the rodent hippocampus is crucial to the encoding, consolidation and retrieval of object memory. Next, it was determined that there is a delay-dependent involvement of the hippocampus in object memory, implying that other structures may be supporting the memory prior to the recruitment of hippocampus. In addition, when the context memory and object memory could be further dissociated, by altering the task design, the results imply a necessary role for the hippocampus in the object memory, irrespective of context. Also, making the task more perceptually demanding, by requiring the mice to perform a two-dimensional to three-dimensional association between stimuli, engaged the hippocampus. Then, in the traditional NOR task, long and short training exploration times were imposed to determine brain region activity for weak and strong object memory. The inactivation and immunohistochemistry findings imply weak object memory is perirhinal cortex dependent, while strong object memory is hippocampal-dependent. Taken together, the findings suggest that mice, like humans, process object memory on a continuum from weak to strong, recruiting the hippocampus conditionally for strong familiarity. Confirming this functional similarity between the rodent and human object memory systems could be beneficial for future studies investigating memory disorders.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004580
Subject Headings: Memory--Research., Mice as laboratory animals., Hippocampus (Brain)--Physiology., Episodic memory., Neurotransmitter receptors., Cellular control mechanisms., Cellular signal transduction., Human information processing.
Format: Document (PDF)

Title: Circulating Cell-free DNA and Interleukin-6 Expression Following Acute High-Intensity Interval Exercise in Obesity.
Creator: Ferrandi, Peter J., Huang, Chun-Jung, Florida Atlantic University, College of Education, Department of Exercise Science and Health Promotion
Abstract/Description: The primary purpose of this study was to examine the impact of acute highintensity interval Exercise (HIIE) on plasma cfDNA and IL-6 responses in obese and normal-weight subjects. Fifteen subjects (8 obese and 7 normal-weight) were recruited to participate in an acute HIIE protocol. Our results demonstrated a significant elevation across time in plasma cfDNA and IL-6 immediately following acute HIIE, with no difference between obese and normal-weight subjects. Furthermore, cfDNA was not...
Show moreThe primary purpose of this study was to examine the impact of acute highintensity interval Exercise (HIIE) on plasma cfDNA and IL-6 responses in obese and normal-weight subjects. Fifteen subjects (8 obese and 7 normal-weight) were recruited to participate in an acute HIIE protocol. Our results demonstrated a significant elevation across time in plasma cfDNA and IL-6 immediately following acute HIIE, with no difference between obese and normal-weight subjects. Furthermore, cfDNA was not correlated with IL-6 in response to acute HIIE in either group. These findings indicate that the obese state does not further exacerbate the release of acute HIIE-induced inflammatory mediators (cfDNA and IL-6), which suggests that HIIE training may serve as a time-effective exercise strategy to improve obesity-associated inflammation.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004929, http://purl.flvc.org/fau/fd/FA00004929
Subject Headings: Interval training--Physiological aspects., Exercise--Physiological aspects., Physical education and training--Measurement., Gene expression., Cellular control mechanisms.
Format: Document (PDF)

Title: Over-Expression of BDNF Does Not Rescue Sensory Deprivation-Induced Death of Adult-Born Olfactory Granule Cells.
Creator: Berger, Rachel A., Guthrie, Kathleen M., Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: It is of interest to understand how new neurons incorporate themselves into the existing circuitry of certain neuronal populations. One such population of neurons is that which are born in the subventricular zone (SVZ) and migrate to the olfactory bulb where they differentiate into granule cells. Another area of interest is the role of brain-derived neurotrophic factor (BDNF) on the survival and overall health of these neurons. This study aimed to test whether or not BDNF is a survival factor...
Show moreIt is of interest to understand how new neurons incorporate themselves into the existing circuitry of certain neuronal populations. One such population of neurons is that which are born in the subventricular zone (SVZ) and migrate to the olfactory bulb where they differentiate into granule cells. Another area of interest is the role of brain-derived neurotrophic factor (BDNF) on the survival and overall health of these neurons. This study aimed to test whether or not BDNF is a survival factor for adult-born granule cells. Here were utilized a transgenic mouse model over-expressing BDNF under the α- calcium/calmodulin-dependent protein kinase II (CAMKIIα) promoter, and tested its effect on olfactory granule cells under sensory deprived conditions. Results from this experiment indicated that there was no significant difference in cell death or cell survival when comparing transgenic and wild type animals. We concluded that BDNF is not a survival factor for adult-born granule cells.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004722, http://purl.flvc.org/fau/fd/FA00004722
Subject Headings: Cellular control mechanisms, Mice as laboratory animals, Nervous system -- Diseases -- Gene therapy, Neural circuitry, Neuroplasticity, Neurotransmitter receptors, Sensory deprivation, Sensory neurons -- Testing
Format: Document (PDF)

Title: Presynaptic Determinants of Synaptic Strength and Energy Efficiency at Drosophila Neuromuscular Junctions.
Creator: Lu, Zhongmin, Macleod, Gregory, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Changes in synaptic strength underlie synaptic plasticity, the cellular substrate for learning and memory. Disruptions in the mechanisms that regulate synaptic strength closely link to many developmental, neurodegenerative and neurological disorders. Release site probability (PAZ) and active zone number (N) are two important presynaptic determinants of synaptic strength; yet, little is known about the processes that establish the balance between N and PAZ at any synapse. Furthermore, it is...
Show moreChanges in synaptic strength underlie synaptic plasticity, the cellular substrate for learning and memory. Disruptions in the mechanisms that regulate synaptic strength closely link to many developmental, neurodegenerative and neurological disorders. Release site probability (PAZ) and active zone number (N) are two important presynaptic determinants of synaptic strength; yet, little is known about the processes that establish the balance between N and PAZ at any synapse. Furthermore, it is not known how PAZ and N are rebalanced during synaptic homeostasis to accomplish circuit stability. To address this knowledge gap, we adapted a neurophysiological experimental system consisting of two functionally differentiated glutamatergic motor neurons (MNs) innervating the same target. Average PAZ varied between nerve terminals, motivating us to explore benefits for high and low PAZ, respectively. We speculated that high PAZ confers high-energy efficiency. To test the hypothesis, electrophysiological and ultrastructural measurements were made. The terminal with the highest PAZ released more neurotransmitter but it did so with the least total energetic cost. An analytical model was built to further explore functional and structural aspects in optimizing energy efficiency. The model supported that energy efficiency optimization requires high PAZ. However, terminals with low PAZ were better able to sustain neurotransmitter release. We suggest that tension between energy efficiency and stamina sets PAZ and thus determines synaptic strength. To test the hypothesis that nerve terminals regulate PAZ rather than N to maintain synaptic strength, we induced sustained synaptic homeostasis at the nerve terminals. Ca2+ imaging revealed that terminals of the MN innervating only one muscle fiber utilized greater Ca2+ influx to achieve compensatory neurotransmitter release. In contrast, morphological measurements revealed that terminals of the MN inner vating multiple postsynaptic targets utilized an increase in N to achieve compensatory neurotransmitter release, but this only occurred at the terminal of the affected postsynaptic target. In conclusion, this dissertation provides several novel insights into a prominent question in neuroscience: how is synaptic strength established and maintained. The work indicates that tension exists between energy efficiency and stamina in neurotransmitter release likely influences PAZ. Furthermore, PAZ and N are rebalanced differently between terminals during synaptic homeostasis.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004519, http://purl.flvc.org/fau/fd/FA00004519
Subject Headings: Drosophila melanogaster--Nervous system., Drosophila melanogaster--Cytogenetics., Fruit-flies--Development., Fruit-flies--Nervous system., Genetic transcription., Transcription factors., Cellular signal transduction., Cellular control mechanisms., Myoneural junction.
Format: Document (PDF)

Cellular control mechanisms (13)	+ -
Cellular signal transduction (7)	+ -
Cellular control mechanisms. (6)	+ -
Apoptosis (4)	+ -
Cell differentiation (4)	+ -

Cellular signal transduction. (4)	+ -
Mice as laboratory animals (4)	+ -
Neurotransmitter receptors (4)	+ -
Gene expression (3)	+ -
Genetic transcription (3)	+ -
Drosophila melanogaster -- Cytogenetics (2)	+ -
Drosophila melanogaster--Cytogenetics. (2)	+ -
Genetic transcription. (2)	+ -
Hippocampus (Brain) (2)	+ -
Research (2)	+ -
Transcription factors (2)	+ -
Transcription factors. (2)	+ -
Adenosine (1)	+ -
Apoptosis. (1)	+ -
Association of ideas (1)	+ -
Cancer (1)	+ -
Cancer cells (1)	+ -
Cell cycle (1)	+ -
Cell differentiation. (1)	+ -
Cell membranes (1)	+ -
Cell receptors. (1)	+ -
Cognitive neuroscience (1)	+ -
Cognitive psychology (1)	+ -
Cytogenetics (1)	+ -
Developmental genetics (1)	+ -

Charles E. Schmidt College of Science (12)	+ -
Florida Atlantic University (11)	+ -
Department of Biomedical Science (7)	+ -
Charles E. Schmidt College of Medicine (6)	+ -
Department of Biological Sciences (6)	+ -

Department of Psychology (3)	+ -
Murphey, Rodney K. (3)	+ -
Stackman, Robert W. (3)	+ -
Kantorow, Marc (2)	+ -
Asgeirsdottir, Herborg Nanna (1)	+ -
Bakina, Olga (1)	+ -
Berger, Rachel A. (1)	+ -
Borgen, Melissa A. (1)	+ -
Center for Complex Systems and Brain Sciences (1)	+ -
Chauss, Daniel C. (1)	+ -
Cinalli, David A. (1)	+ -
Cohen, Sarah J. (1)	+ -
College of Education (1)	+ -
Department of Exercise Science and Health Promotion (1)	+ -
Ferrandi, Peter J. (1)	+ -
Gesualdi, Scott C. (1)	+ -
Guthrie, Kathleen M. (1)	+ -
Huang, Chun-Jung (1)	+ -
Lalonde, Maureen S. (1)	+ -
Li, Zhongwei (1)	+ -
Liu, Huan (1)	+ -
Lloyd, Brandon N. (1)	+ -
Lu, Zhongmin (1)	+ -
Macleod, Gregory (1)	+ -
Mattucci, Lyndzie. (1)	+ -

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