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- Title
- Vascular endothelial growth factor (VEGF), BCL-2, and BAX expression in fibropapilloma tumor tissue and skin tissue of sea turtles.
- Creator
- Bancalari-Schmidlapp, Angela., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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In sea turtles, the study of the etiology and development of fibropapillomatosis is not fully understood. Sea turtle fibropapillomatosis is a disease characterized by the proliferation of skin fibropapillomas and occasional internal fibromas. In this study, sea turtle fibropapilloma tumor and healthy tissue samples were used to look at VEGF, BCL-2 and Bax expression. Cancer tumors have a well established pattern of protein expression that involves overexpression of vascular endothelial growth...
Show moreIn sea turtles, the study of the etiology and development of fibropapillomatosis is not fully understood. Sea turtle fibropapillomatosis is a disease characterized by the proliferation of skin fibropapillomas and occasional internal fibromas. In this study, sea turtle fibropapilloma tumor and healthy tissue samples were used to look at VEGF, BCL-2 and Bax expression. Cancer tumors have a well established pattern of protein expression that involves overexpression of vascular endothelial growth factor (VEGF), responsible for the growth of new blood vessels, and a high BCL-2 to Bax ratio that leads to uncontrolled cell proliferation. Real time PCR was used to analyze VEGF expression, and Western blot techniques were used to measure BCL-2 and Bax expression. The results indicated that expression of VEGF was not significantly higher in tumor vs. skin tissue. For the differential expression of BCL-2 and Bax, the results were not in agreement with the established levels found in cancer studies, showing no significant change in BCL-2 expression and significantly higher levels of Bax in tumor vs. healthy tissue.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/209981
- Subject Headings
- Sea turtles, Physiology, Cancer, Pathophysiology, Vascular endothelial growth factors, Pathophysiology, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Uncovering the role of the rodent dorsal hippocampus in spatial and object memory retrieval.
- Creator
- Rios, Lisa, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
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Male C7BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae. After confirming that intrahippocampal microinfusion of muscimol impaired hippocampal function, demonstrated by impaired performance in the Morris water maze, the influence of intrahippocampal muscimol was tested in the Novel Object Recognition paradigm. During a test session 24 h after the last habituation/sample session, mice were presented with one familiar object and one novel object. Successful retention of object...
Show moreMale C7BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae. After confirming that intrahippocampal microinfusion of muscimol impaired hippocampal function, demonstrated by impaired performance in the Morris water maze, the influence of intrahippocampal muscimol was tested in the Novel Object Recognition paradigm. During a test session 24 h after the last habituation/sample session, mice were presented with one familiar object and one novel object. Successful retention of object memory was inferred if mice spent more time exploring the novel object than the familiar object. Results demonstrate that muscimol infused into dorsal CA1 region prior to the test session eliminates novel object preference, indicating that the hippocampus is necessary for the retrieval of this non-spatial memory - a topic that has garnered much debate. Understanding the similarities between rodent and human hippocampal function could enable future animal studies to effectively answer questions about diseases and disorders affecting human learning and memory.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3172696
- Subject Headings
- Rodents as laboratory animals, Memory, Research, Cellular signal transduction, Cognitive neuroscience, Hippocampus (Brain), Space perception
- Format
- Document (PDF)
- Title
- The effect of small conductance calcium-activated potassium channels on emotional learning and memory.
- Creator
- Sanguinetti, Shannon, Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
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Small conductance Ca2+-activated K+ (SK) channels have been shown to alter the encoding of spatial and non-spatial memory in the hippocampus by shaping glutamatergic postsynaptic potentials and modulating NMDA receptor-dependent synaptic plasticity. When activated, dendritic SK channels reduce hippocampal neuronal excitability and LTP. Similar SK channel properties have been demonstrated in lateral amygdala (LA) pyramidal neurons. Additionally, induction of synaptic plasticity and beta...
Show moreSmall conductance Ca2+-activated K+ (SK) channels have been shown to alter the encoding of spatial and non-spatial memory in the hippocampus by shaping glutamatergic postsynaptic potentials and modulating NMDA receptor-dependent synaptic plasticity. When activated, dendritic SK channels reduce hippocampal neuronal excitability and LTP. Similar SK channel properties have been demonstrated in lateral amygdala (LA) pyramidal neurons. Additionally, induction of synaptic plasticity and beta-adrenoreceptor activation in LA pyramidal neurons causes PKA-mediated internalization of SK channels from the postsynaptic density. Chronic activation of the amygdala through repetitive stressful stimuli can lead to excitatory synaptic strengthening that may create permanent hyper-excitability in its circuitry. This mechanism may contribute to a number of mood and anxiety disorders. The selective influence of SK channels in the LA on anxiety and fear conditioning are not known. The thesis project outlined herein examined whether SK channel blockade by bee venom peptide, apamin, during a repetitive acute fear conditioning paradigm was sufficient to alter fear memory encoding and the resulting behavioral outcome. Following the final fear memory test session, mice were tested in the open field immediately after the second fear conditioning test session. The findings indicate that intracranial LA microinfusions of apamin did not affect memory encoding or subsequent anxiety.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004543, http://purl.flvc.org/fau/fd/FA00004543
- Subject Headings
- Biological transport -- Research, Cellular signal transduction, Memory -- Research, Mice as laboratory animals, Potassium channels -- Physiological effect
- Format
- Document (PDF)
- Title
- Temporal response of creatine kinase and fibroblast growth factor-21 to high and low repetition resistance training programs.
- Creator
- Blanco, Rocky, Zourdos, Michael C., Florida Atlantic University, College of Education, Department of Exercise Science and Health Promotion
- Abstract/Description
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The purpose of this study was to examine the acute and temporal response of CK- MM and FGF-21 to 3-day/wk. different repetition-range, volume-equated resistance training programs over 8-weeks in previously trained males. Sixteen trained, college- aged males were counterbalanced into high (DUP-HR) or low (DUP-LR) repetition groups. Subjects performed the squat and bench press 3x/wk. for 8 weeks. Blood samples were collected at various intervals throughout the study. Trained individuals did not...
Show moreThe purpose of this study was to examine the acute and temporal response of CK- MM and FGF-21 to 3-day/wk. different repetition-range, volume-equated resistance training programs over 8-weeks in previously trained males. Sixteen trained, college- aged males were counterbalanced into high (DUP-HR) or low (DUP-LR) repetition groups. Subjects performed the squat and bench press 3x/wk. for 8 weeks. Blood samples were collected at various intervals throughout the study. Trained individuals did not elicit significant acute or chronic changes in CK-MM or FGF-21 following training and the lack of change was present in both groups. Additionally, neither biomarker correlated with changes in 1RM strength. There was a very strong correlation between acute mean (r=0.95) and acute percentage change (r=0.97) increase from pre training to post training in week #1. Additionally, a moderate correlation in percentage change was observed (r=0.59) of both biomarkers from pre training to 48 hours post training in week #2.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004429, http://purl.flvc.org/fau/fd/FA00004429
- Subject Headings
- Bioenergetics, Cellular signal transduction, Fibroblast growth factors, Metabolic syndrome -- Pathophysiology, Protein kinases -- Inhibitors -- Therapeutic use
- Format
- Document (PDF)
- Title
- Taurine inhibits glutamate-induced excitotoxicity through a calpain dependent pathway.
- Creator
- Leon, Rebecca, Prentice, Howard, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Taurine, an endogenous ammo acid and neuromodulator, has been found to be neuroprotective against numerous forms of neurotoxicity including glutamate-induced excitotoxicity. Previously we have shown that taurine inhibits glutamate-induced calcium influx through VGCCs and NMDA receptors. Although the neuroprotective effects of taurine against excitotoxicity have been attributed to its intracellular Ca2+ regulatory functions, the complete mechanism underling taurine neuroprotection has remained...
Show moreTaurine, an endogenous ammo acid and neuromodulator, has been found to be neuroprotective against numerous forms of neurotoxicity including glutamate-induced excitotoxicity. Previously we have shown that taurine inhibits glutamate-induced calcium influx through VGCCs and NMDA receptors. Although the neuroprotective effects of taurine against excitotoxicity have been attributed to its intracellular Ca2+ regulatory functions, the complete mechanism underling taurine neuroprotection has remained unclear. Using primary rat cortical neuronal cell cultures, we have determined key cytosolic components to the mechanism of taurine neuroprotection. In this study we have found that taurine inhibits excitotoxicity by suppressing glutamate-induced elevations in [Ca2+]i, preventing calpain activation, and inhibiting reductions in Bel- 2:Bax ratios and consequently activation of the intrinsic pathway.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00000788
- Subject Headings
- Cellular signal transduction, Taurine--Physiological effect, Proteolytic enzymes--Research
- Format
- Document (PDF)
- Title
- Study of cell penetrating peptides with Raman spectroscopy and microscopy.
- Creator
- Ye, Jing., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the...
Show moreCell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the Antennapedia homeodomain protein of Drosophila, was measured in single, living melanoma cells. Carbon-13 labeling of the Phe residue of penetratin was used to shift the intense aromatic ring-breathing vibrational mode from 1003 to 967 cm-1, thereby enabling the peptide to be traced in cells. Difference spectroscopy and principal components analysis (PCA) were used independently to resolve the Raman spectrum of the peptide from the background cellular Raman signals., On the basis of the position of the amide I vibrational band in the Raman spectra, the secondary structure of the peptide was found to be mainly random coil and b-strand in the cytoplasm, and possibly assembling as b-sheets in the nucleus. Next, label-free transportan was studied with the same methodology. The peptide, besides predominantly a-helix, adopted a significant portion of b-sheet conformation in the cytoplasm and nucleolus, which is different from the peptide in aqueous solution. The peptide microenvironment was also probed through H-bonding reported by the tyrosine Fermi doublet. Transportan displayed a tendency to accumulate in the cytoplasm over time which was unlike penetratin, which concentrated in the nucleus. The relative concentration of CPPs in various locations of live melanoma cells was directly estimated from the Raman spectra using average Phe concentration in the cell as an internal standard., The rapid entry and almost uniform cellular distribution of both peptides, as well as the lack of correlation between peptide and lipid Raman signatures, indicated that the mechanism of CPP internalization under the conditions of study was probably non-endocytotic. Last, transportan and penetratin were studied using polarized Raman spectroscopy for more detailed vibrational spectroscopic information of the two peptides in water and TFE solutions. The majority of the bands in the Raman spectra of the peptides were highly polarized, consistent with the high symmetry of aromatic ring side chain vibrational bands dispersed throughout the spectra. This work has provided new insights into the structure of CPPs in live cells and in solutions.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3342344
- Subject Headings
- Peptides, Analysis, Infrared spectroscopy, Raman spectroscopy, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Study of Cell Penetrating Peptide Uptake and Cancer Cell Discrimination with Raman Spectroscopy and Microscopy.
- Creator
- Cosme, Patrick Jason, Terentis, Andrew C., Florida Atlantic University, Charles E Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs,...
Show moreCell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs, with mammalian cells CRM’s capability to discriminate control and treated cell groups was verified by principal component analysis (PCA) and linear discriminant analysis (LDA) and was 93-100% accurate We’ve determined that at a concentration of 20 μM TP enters cells through a non-endocytotic mechanism, has a high affinity for the cytoplasm and membranes, and results in a significant increase in cellular stiffness Our work provides the first direct evidence of this cell-stiffening phenomenon SFTI-1, the smallest member of a bicyclic, cysteine rich class of CPPs, was examined by CRM to determine the potential role of cyclic structure on cellular uptake The peptide, along with monocyclic and linear analogs was heavy isotope labeled and incubated with mammalian cells at numerous concentrations and timespans Our work is the first SFTI-1 uptake study forgoing the use of fluorophore conjugates, which have been linked to artificial cellular uptake We demonstrate herein the absence of any CRM detectable uptake, providing the first evidence that SFTI-1 may not be a CPP Finally, CRM was applied to the discrimination of normal and basal cell carcinoma cells obtained from the same donor The use of patient matched cells avoids the normal biochemical variations that exist among individuals, ensuring that discrimination is based solely on the cell’s diseased state CRM spectra, analyzed by PCA and LDA, were capable of spectral discrimination with 100% accuracy Major differences in the cancerous cells were an increase in lipids and nucleic acids, and an overall decrease in protein We also demonstrate an enhancement in Raman signal through the use of an aluminum foil substrate, providing a practical approach for measuring cells with thin morphologies
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004756
- Subject Headings
- Peptides--Analysis, Peptides--Therapeutic use, Peptides--Physiological transport, Cellular signal transduction, Raman spectroscopy, Infrared spectroscopy
- Format
- Document (PDF)
- Title
- Studies on the mechanism by which sulindac sensitizes cancer cells to oxidative stress.
- Creator
- Kreymerman, Alexander, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Sulindac is a known NSAID that has also been shown to have anti-cancer activity that is not related to its ability to inhibit COX 1 and 2. During the past 15 years there have been a large number of studies attempting to elucidate its mechanism of action. Our laboratory has shown that sulindac can both protect normal cells and enhance the killing of cancer cells under oxidative stress from H2O2 and TBHP. However, except for mitochondrial dysfunction and ROS production, the mechanism by which...
Show moreSulindac is a known NSAID that has also been shown to have anti-cancer activity that is not related to its ability to inhibit COX 1 and 2. During the past 15 years there have been a large number of studies attempting to elucidate its mechanism of action. Our laboratory has shown that sulindac can both protect normal cells and enhance the killing of cancer cells under oxidative stress from H2O2 and TBHP. However, except for mitochondrial dysfunction and ROS production, the mechanism by which sulindac sensitized the cancer cells to oxidative stress remains unknown. Results of this research project suggest that the effect of sulindac and oxidative stress not only involves mitochondrial ROS production, but also aspects of the preconditioning response. In normal cells this leads to survival by a preconditioning pathway, likely involving PKCε. . However, cancer cells react by initiating a pathway leading to apoptosis involving PKCδ.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3183124
- Subject Headings
- Proteins, Chemical modification, Cellular signal transduction, Biochemical markers, Diagnostic use, Drug resistance in cancer cells, Oxidation-reduction reaction
- Format
- Document (PDF)
- Title
- Role of methionine sulfoxide reductase in thermal-induced spreading depression coma in Drosophila melanogaster.
- Creator
- Schey, Karin., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Drosophila melanogaster encounter periods of increased temperature or decreased oxygen in its native environment. One consequence of these environmental stresses is increased production of reactive oxygen species that damage major molecules within cells. Another consequence is that flies fall into a protective coma where biological functions are minimized to conserve energy expenditures. This biological phenomenon is called spreading depression. The overarching aim of this project is to...
Show moreDrosophila melanogaster encounter periods of increased temperature or decreased oxygen in its native environment. One consequence of these environmental stresses is increased production of reactive oxygen species that damage major molecules within cells. Another consequence is that flies fall into a protective coma where biological functions are minimized to conserve energy expenditures. This biological phenomenon is called spreading depression. The overarching aim of this project is to determine if methionine sulfoxide reductases affect entrance or exit from the protective coma induced by acute thermal stress. The data revealed that complete deficiency of Msr in young flies causes a faster induction of the coma. In both young and old flies, Msr does not affect average recovery time but does affect the pattern of recovery from coma. Entrance into the coma is age dependent with young flies maintaining activity longer than before entering into the coma as compared to old flies.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3355873
- Subject Headings
- Cellular signal transduction, Proteins, Chemical modification, Spreading cortical depression, Oxidation-reduction reaction, Aging, Molecular aspects, Mutation (Biology)
- Format
- Document (PDF)
- Title
- A role for polynucleotide phosphorylase in protecting cells and controlling RNA quality under oxidative stress.
- Creator
- Wu, Jinhua., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
RNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG...
Show moreRNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG:A). We further confirmed that E. coli PNPase can specifically bind to an oxidized RNA with a high affinity. An E. coli strain deficient in PNPase (pnp) is hypersensitive to hydrogen peroxide (H2O2). Importantly, the level of H2O2-induced RNA damage, measured by the content of 8-hydroxyguanosine, increases significantly in the pnp mutant cells. Consistent with the notion that PNPase plays a direct role in these processes, introduction of the pnp gene encoding E. coli PNPase can restore the viability and RNA oxidation level of the pnp mutant cells in response to H2O2 treatment. Interestingly, degradosome-association is not required for PNPase to protect cell against oxidative stress. PNPase is evolutionary conserved in most of organisms of all domains of life. The human polynucleotide phosphorylase (hPNPase) localizes mainly in mitochondria and plays pleiotropic roles in cell differentiation and has been previously shown to bind 8- oxoG-RNA with a high affinity. Here we show that similar to E. coli PNPase, hPNPase plays an indispensable role in protecting HeLa cells against oxidative stress. The viability in HeLa cell and 8-oxoG levels in RNA are inversely correlated in response to H2O2- treatment. After removal of oxidative challenge, the elevated level of 8-oxoG in RNA decreases, suggesting the existence of surveillance mechanism(s) for cleaning up oxidized RNA., We have shown that hPNPase may be responsible for the surveillance of oxidized RNA in mammalian cells.Overexpresion of hPNPase reduces RNA oxidation and increases HeLa cell viability against H2O2 insult. Conversely, hPNPase knockdown decreases the viability and increases 8-oxoG level in HeLa cells exposed to H2O2. Taken together, our results suggest that RNA oxidation is a challenging problem for living organisms, and PNPase may play an important role in protecting both prokaryotic and eukaryotic cells by limiting damage to RNA under oxidative stress.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/FAU/186302
- Subject Headings
- RNA, Metabolism, Biopolymers, Physiological transport, Bacterial genetics, Proteins, Synthesis, Cellular signal transduction
- Format
- Document (PDF)
- Title
- RNA oxidative damage and ribosomal RNA surveillance under oxidative stress.
- Creator
- Liu, Min, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
We have studies oxidative damage of RNA, a major type of cellular macromolecules. RNA is a primary target of reactive oxygen species (ROS). Under oxidative stress, most nucleic acid damages in Escherichia coli (E.coli) are present in RNA as shown by high levels of 8-oxo-G, an oxidized form of guanine. Increased RNA oxidation is closely correlated to cell death under oxidative stress. Surprisingly, neither RNA structure nor association with proteins protects RNA from oxidation... Our results...
Show moreWe have studies oxidative damage of RNA, a major type of cellular macromolecules. RNA is a primary target of reactive oxygen species (ROS). Under oxidative stress, most nucleic acid damages in Escherichia coli (E.coli) are present in RNA as shown by high levels of 8-oxo-G, an oxidized form of guanine. Increased RNA oxidation is closely correlated to cell death under oxidative stress. Surprisingly, neither RNA structure nor association with proteins protects RNA from oxidation... Our results demonstrate a major role for RNA degradation in controlling oxidized RNA. We have identified activities that may work in specific pathways for selectively degrading damaged RNA. These activities may play pivotal rold in controlling oxidized RNA and protecting cells under oxidative stress.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3355620
- Subject Headings
- RNA, Metabolism, Cellular signal transduction, Genetic translation, Molecular biology
- 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.
Show less - 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
- Regulation of rapid signaling at the cone ribbon synapse via distinct pre- and postsynaptic mechanisms.
- Creator
- Rowan, Matthew JM., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Background: Light-adaptation is a multifaceted process in the retina that helps adjust the visual system to changing illumination levels. Many studies are focused on the photochemical mechanism of light-adaptation. Neural network adaptation mechanisms at the photoreceptor synapse are largely unknown. We find that large, spontaneous Excitatory Amino Acid Transporter (EAATs) activity in cone terminals may contribute to cone synaptic adaptation, specifically with respect to how these signals...
Show moreBackground: Light-adaptation is a multifaceted process in the retina that helps adjust the visual system to changing illumination levels. Many studies are focused on the photochemical mechanism of light-adaptation. Neural network adaptation mechanisms at the photoreceptor synapse are largely unknown. We find that large, spontaneous Excitatory Amino Acid Transporter (EAATs) activity in cone terminals may contribute to cone synaptic adaptation, specifically with respect to how these signals change in differing conditions of light. EAATs in neurons quickly transport glutamate from the synaptic cleft, and also elicit large thermodynamically uncoupled Cl- currents when activated. We recorded synaptic EAAT currents from cones to study glutamate-uptake events elicited by glutamate release from the local cone, and from adjacent photoreceptors. We find that cones are synaptically connected via EAATs in dark ; this synaptic connection is diminished in light-adapted cones. Methods: Whole-cell patch-clamp was performed on dark- and transiently light-adapted tiger salamander cones. Endogenous EAAT currents were recorded in cones with a short depolarization to -10mV/2ms, while spontaneous transporter currents from network cones were observed while a local cone holding at -70mV constantly. DHKA, a specific transporter inhibitor, was used to identify EAAT2 currents in the cone terminals, while TBOA identified other EAAT subtypes. GABAergic and glycinergic network inputs were always blocked with picrotoxin and strychnine. Results: Spontaneous EAAT currents were observed in cones held constantly at -70mV in dark, indicating that the cones received glutamate inputs from adjacent photoreceptors. These spontaneous EAAT currents disappeared in presence of a strong light, possibly because the light suppressed glutamate releases from the adjacent photoreceptors. The spontaneous EAAT currents were blocked with TBOA, but not DHKA, an inhibitor for EAAT2 subtype, suggesting that a, non-EAAT 2 subtype may reside in a basal or perisynaptic area of cones, with a specialized ability to bind exocytosed glutamate from adjacent cones in dark. Furthermore, these results could be artificially replicated by dual-electrode recordings from two adjacent cones. When glutamate release was elicited from one cone, the TBOA-sensitive EAAT currents were observed from the other cone. Conclusions: Cones appear to act like a meshwork, synaptically connected via glutamate transporters. Light attenuates glutamate release and diminishes the cone-cone synaptic connections. This process may act as an important network mechanism for cone light adaptation.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3337186
- Subject Headings
- Synapses, Neural transmission, VIsual perception, Presynaptic receptors, Molecular neurobiology, Glutamic acid, Neural receptors, Cellular signal transduction, Retina, Cytology
- Format
- Document (PDF)
- Title
- Purification and characterization of two members of the protein tyrosine phosphatase family: dual specificity phosphatase PVP and low molecular weight phosphatase WZB.
- Creator
- Livingston, Paula A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Two protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only...
Show moreTwo protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only pnitrophenylphosphate was a substrate with no affinity for Ç-naphthyl phosphate and phosphoserine. Optimal conditions for activity with PNPP were found at a pH of 5 with a KM of 1.1mM, kcat of 35.4s-1 and kcat/KM of 32.2s-1mM-1. Inhibition studies showed that phosphate, fluoride, and molybdate were competitive inhibitors with Ki of 3.2mM, 71.7mM, and 50.4(So(BM respectively and hydrogen peroxide abolished activity. Active site mutants of WZB Cys9Ser and Asp115Asn showed no activity.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/332911
- Subject Headings
- Protein-tyrosine phosphatase, Cellular signal transduction, Cell cycle, Regulation, Membrane proteins, Structure-activity relationships, Protein kinases
- 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.
Show less - 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
- Polyglutamine aggregates stimulate ER stress and trigger apoptosis by activating BH-3 only protein Bim.
- Creator
- Bhagavatula, Nithya, Wei, Jianning, Florida Atlantic University
- Abstract/Description
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Huntington's disease (HD) is an inherited neurological disorder characterized by a selective loss of neurons in the striatum and cortex leading to involuntary movement, dementia and eventually cell death. HD is caused by an expanded polyglutamine (PolyQ) repeat in Huntingtin (Htt) protein. It is well known that misfolded mutant Htt could form intracellular aggregates, trigger ER stress and ultimately lead to apoptosis. However, the molecular link between ER stress and apoptosis in...
Show moreHuntington's disease (HD) is an inherited neurological disorder characterized by a selective loss of neurons in the striatum and cortex leading to involuntary movement, dementia and eventually cell death. HD is caused by an expanded polyglutamine (PolyQ) repeat in Huntingtin (Htt) protein. It is well known that misfolded mutant Htt could form intracellular aggregates, trigger ER stress and ultimately lead to apoptosis. However, the molecular link between ER stress and apoptosis in mitochondria is poorly understood. In the present study, we identified Bim (Bcl-2 interacting mediator of cell death) as the essential protein. We first established a cellular model of HD by over expressing the Nterminus of wild type and mutant Htt into HEK293 cell lines. We showed that the accumulation and aggregation of misfolded mutant Htt protein triggers ER stress and apoptosis. The Bim protein expression level was greatly increased in mutant Htt transfected cells and this increase was partially due to up-regulation of Bim mRNA as analyzed using quantitative RT-PCR. We further showed that Bim phosphorylation also played an important role in regulating Bim expression. Moreover, up-regulation of Bim facilitates the translocation of Bax to mitochondrial membrane, which lead to cytochrome c release and apoptosis. We also silenced Bim using siRNA to further investigate the essential role of Bim in mutant Htt induced ER stress and apoptosis. Identifying the Bim pathway that is altered in response to the mutant Htt protein is important for understanding the cellular processes impacted by the disease.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00000726
- Subject Headings
- Nervous system--Degeneration--Molecular aspects, Apoptosis, Cellular signal transduction, Huntington's disease--Genetic aspects, Huntington's disease--Pathophysiology
- Format
- Document (PDF)
- Title
- Phenotypic and behavioral effects of methionine sulfoxide reductase deficiency and oxidative stress in Drosophila melanogaster.
- Creator
- Mulholland, Kori., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Harman's theory of aging proposes that a buildup of damaging reactive oxygen species (ROS) is one of the primary causes of the deleterious symptoms attributed to aging. Cellular defenses in the form of antioxidants have evolved to combat ROS and reverse damage; one such group is the methionine sulfoxide reductases (Msr), which function to reduce oxidized methionine. MsrA reduces the S enantiomer of methionine sulfoxide, Met-S-(o), while MsrB reduces the R enantiomer, Met-R-(o). The focus of...
Show moreHarman's theory of aging proposes that a buildup of damaging reactive oxygen species (ROS) is one of the primary causes of the deleterious symptoms attributed to aging. Cellular defenses in the form of antioxidants have evolved to combat ROS and reverse damage; one such group is the methionine sulfoxide reductases (Msr), which function to reduce oxidized methionine. MsrA reduces the S enantiomer of methionine sulfoxide, Met-S-(o), while MsrB reduces the R enantiomer, Met-R-(o). The focus of this study was to investigate how the absence of one or both forms of Msr affects locomotion in Drosophila using both traditional genetic mutants and more recently developed RNA interference (RNAi) strains. Results indicate that lack of MsrA does not affect locomotion. However, lack of MsrB drastically reduces rates of locomotion in all age classes. Furthermore, creation of an RNAi line capable of knocking down both MsrA and MsrB in progeny was completed.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3362558
- Subject Headings
- Drosophila melanogaster, Genetics, Aging, Molecular aspects, Oxidative stress, Mitochondrial pathology, Cellular signal transduction, Oxidation-reduction reaction, Biochemical markers, Mutation (Biology)
- Format
- Document (PDF)
- Title
- Peroxiredoxin 3 and Methionine sulfoxide reductase A are Essential for Lens Cell Viability by Preserving Lens Cell Mitochondrial Function through Repair of Cytochrome c.
- Creator
- Lee, Wanda, Florida Atlantic University, Kantorow, Marc, Charles E. Schmidt College of Science, Department of Biomedical Science
- Abstract/Description
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The central premise of this dissertation is that mitochondrial antioxidant enzymes are essential to lens cell viability by preserving lens cell mitochondria and protecting and/or repairing lens cell proteins, and two mitochondrial-specific antioxidant enzymes, Peroxiredoxin 3 (PRDX3) and Methionine sulfoxide reductase A (MsrA), are explored. In this dissertation, we will examine the expression ofPRDX3 in the human lens, its colocalization to the lens cell mitochondria, its ability to be...
Show moreThe central premise of this dissertation is that mitochondrial antioxidant enzymes are essential to lens cell viability by preserving lens cell mitochondria and protecting and/or repairing lens cell proteins, and two mitochondrial-specific antioxidant enzymes, Peroxiredoxin 3 (PRDX3) and Methionine sulfoxide reductase A (MsrA), are explored. In this dissertation, we will examine the expression ofPRDX3 in the human lens, its colocalization to the lens cell mitochondria, its ability to be induced by H20 2-oxidative stress, and speculate how PRDX3 function/sf could affect the lens. We will also examine the reduced levels of MsrA by targeted gene silencing and its effect on reactive oxygen species production and mitochondrial membrane potential in human lens cells to determine its role in mitochondrial function in the lens. Lastly, we will examine the ability of MsrA to repair and restore function to a critical mitochondrial protein, Cytochrome c. The collective evidence strongly indicates that the loss of mitochondrial-specific enzymes, such as PRDX3 and MsrA, are responsible for increased reactive oxygen species levels, decreased mitochondrial membrane potential, protein aggregation and lens cell death, and further indicates that mitochondrial repair, protective, and reducing systems play key roles in the progression of age-related cataract and other agerelated diseases.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00000868
- Subject Headings
- Genetic regulation, Proteins--Chemical modification, Cellular signal transduction, Eye--Physiology, Mitochondrial pathology
- Format
- Document (PDF)
- Title
- Novel molecular targets for genistein in prostate cancer cells.
- Creator
- Merchant, Kendra T., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Prostate cancer is the most common form of non-skin cancer and the second leading cause of cancer deaths within the United States. The five year survival rate has increased from 69% to 99% over the last 25 years for the local and regional disease, but has remained fairly low (approximately 34%) for the advanced disease. Therefore, current research is aimed at finding complementary or alternative treatments that will specifically target components of the signal transduction, cell-cycle and...
Show moreProstate cancer is the most common form of non-skin cancer and the second leading cause of cancer deaths within the United States. The five year survival rate has increased from 69% to 99% over the last 25 years for the local and regional disease, but has remained fairly low (approximately 34%) for the advanced disease. Therefore, current research is aimed at finding complementary or alternative treatments that will specifically target components of the signal transduction, cell-cycle and apoptosis pathways to induce cell death, with little or no toxic side effects to the patient. In this study we investigated the effect of genistein on expression levels of genes involved in these pathways. Genistein is a (4 , 5 , 7-trihydroxyisoflavone) is a major isoflavone constituent of soy that has been shown to inhibit growth proliferation and induce apoptosis in cancer cells. The mechanism of genistein-induced cell death and potential molecular targets for genistein in LNCaP prostate cancer c ells was investigated using several techniques. The chemosensitivity of genistein towards the prostate cancer cells was investigated using the ATP and MTS assays and apoptosis induction was determined using apoptosis and caspase assays. Several molecular targets were also identified using cDNA microarray and RT-PCR analysis. Our results revealed that genistein induces cell death in a time and dose-dependent manner and regulates expression levels of several genes involved in carcinogenesis and immunogenicity. Several cell cycle genes were down-regulated, including the mitotic kinesins, cyclins and cyclin dependent kinases, indicating that genistein is able to halt cell cycle progression through the regulation of genes involved in this process., Several members of the Bcl-2 family which are involved in apoptosis were also affected and a number of genes involved in immunogenicity were up-regulated including the DefB1 and HLA membrane receptors. The results of this study provide evidence of genistein's ability to inhibit growth proliferation and induce apoptosis and indicates its potential as an adjuvant in chemotherapy and immunotherapy.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/192986
- Subject Headings
- Prostate, Cancer, Adjuvant treatment, Prostate, Cancer, Molecular aspects, Apoptosis, Molecular aspects, Phytochemicals, Physiological effect, Cellular signal transduction
- 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
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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.
Show less - 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)