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- 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
-
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
- 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
- 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
- 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
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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
- Elucidating the role of Semaphorin 7A in breast cancer.
- Creator
- Garcia-Areas, Ramon A., lragavarapu-Charyulu, Vijaya, Florida Atlantic University, Charles E Schmidt College of Science, Department of Biomedical Science
- Abstract/Description
-
Solid tumors can hijack many of the same programs used in neurogenesis to enhance tumor growth and metastasis, thereby generating a plethora of neurogenesis-related molecules including semaphorins Among them, we have identified Semaphorin7A (SEMA7A) in breast cancer We first used to the DA-3 mammary tumor model to determine the effect of tumor-derived SEMA7A on immune cells We found that tumor-derived SEMA7A can modulate the production of proangiogenic chemokines CXCL2/MIP-2 and CXCL 1, and...
Show moreSolid tumors can hijack many of the same programs used in neurogenesis to enhance tumor growth and metastasis, thereby generating a plethora of neurogenesis-related molecules including semaphorins Among them, we have identified Semaphorin7A (SEMA7A) in breast cancer We first used to the DA-3 mammary tumor model to determine the effect of tumor-derived SEMA7A on immune cells We found that tumor-derived SEMA7A can modulate the production of proangiogenic chemokines CXCL2/MIP-2 and CXCL 1, and prometastatic MMP-9 in macrophages We next aimed to determine the expression and function of SEMA7A in mammary tumor cells We found that SEMA7A is highly expressed in both metastatic human and murine breast cancer cells We show that both TGF-β and hypoxia elicits the production of SEMA 7 A in mammary cells SEMA7 A shRNA silencing in 4T1 cells resulted in decreased mesenchymal markers MMP-3, MMP-13, Vimentin and TGF-β) SEMA7A silenced cells show increased stiffness with reduced migratory and proliferative potential In vivo, SEMA7A silenced 4T1 tumor bearing mice showed decreased tumor growth and metastasis Genetic ablation of host-derived SEMA7A synergized to further decrease the growth and metastasis of 4T1 cells Our findings suggest novel functional roles for SEMA7A in breast cancer and that SEMA7A could be a novel therapeutic target to limit tumor growth and metastasis
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004802
- Subject Headings
- Breast--Cancer--Diagnosis, Semaphorins, Protein precursors, Cellular signal transduction, Cell receptors
- Format
- Document (PDF)
- Title
- Impact of Vitamin C on Genistein-Induced Apoptosis in Prostate Cancer.
- Creator
- Famuyiwa, Toluleke, Kumi-Diaka, James, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
This study determined the impact of vitamin C dose on genistein-induced apoptosis in LNCaP cancer cells at various treatment regimens in vitro. Although the linear regression of viability assay (MTT) indicated a p-value = 0.11; NBT assay reveal a declining SOD activity during cell death. Apoptosis induction was the main mode of treatment induced cell death. The overall data showed the trend of treatment efficacy as;(Gen 10uM + Vit C 40uM) > (Gen 30uM + Vit C 40uM) > (Gen 70uM + Vit C 40uM) >...
Show moreThis study determined the impact of vitamin C dose on genistein-induced apoptosis in LNCaP cancer cells at various treatment regimens in vitro. Although the linear regression of viability assay (MTT) indicated a p-value = 0.11; NBT assay reveal a declining SOD activity during cell death. Apoptosis induction was the main mode of treatment induced cell death. The overall data showed the trend of treatment efficacy as;(Gen 10uM + Vit C 40uM) > (Gen 30uM + Vit C 40uM) > (Gen 70uM + Vit C 40uM) > 10uM genistein > 70uM genistein. The chi-square test for comparing necrosis, apoptosis and life cells showed that Vitamin C could impact genistein-induced apoptosis in LNCaP cells (p = 0.0003). This study forms the basis for in vivo studies of the impact of vitamin C on genistein-induced apoptosis in LNCaP prostate cancer cells.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004497, http://purl.flvc.org/fau/fd/FA00004497
- Subject Headings
- Apoptosis -- Molecular aspects, Cellular signal transduction, Genistein -- Therapeutic use, Phytochemicals -- Physiological effect, Phytochemicals -- Therapeutic use, Prostate -- Cancer -- Adjuvant treatment, Prostate -- Cancer -- Molecular aspects, Vitamin C -- Therapeutic use
- 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
- 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
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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.
Show less - 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
- Methionine sulfoxide reductase (MSR) modulates lifespan andLocomotion in drosophila melanogaster.
- Creator
- Bruce, Lindsay, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Oxidative stress is considered a major factor in the etiology of age related diseases and the aging process itself. Organisms have developed mechanisms to protect against oxidative damage resulting from increased production of reactive oxygen species during aging. One of the major antioxidant systems is the methionine sulfoxide reductase (Msr) enzyme family. The two major Msr enzymes, MsrA and MsrB, can stereospecifically reduce the S and R epimers, respectively, of methionine sulfoxide in...
Show moreOxidative stress is considered a major factor in the etiology of age related diseases and the aging process itself. Organisms have developed mechanisms to protect against oxidative damage resulting from increased production of reactive oxygen species during aging. One of the major antioxidant systems is the methionine sulfoxide reductase (Msr) enzyme family. The two major Msr enzymes, MsrA and MsrB, can stereospecifically reduce the S and R epimers, respectively, of methionine sulfoxide in proteins back to methionine. This study, using Drosophila melanogaster, decribes the first animal system lacking both MsrA and MsrB. The loss of either MsrA or MsrB had no effect on lifespan in Drosophila, but loss of MsrB results in a slight decrease in locomotor activity from middle age onward. Double mutants lacking both forms of Msr have a significantly decreased lifespan and decreased locomotor activity at all ages examined. The double Msr mutants had no detectable increase in protein oxidation or decrease in mitochondrial function and were not more sensitive to oxidative stress. These results suggested that other cellular antioxidant systems were protecting the flies against oxidative damage and the decreased life span observed in the double knockouts was not due to widespread oxidative damage. However, one cannot exclude limited oxidative damage to a specific locus or cell type. In this regard, it was observed that older animals, lacking both MsrA and MsrB, have significantly reduced levels of dopamine, suggesting there might be oxidative damage to the dopaminergic neurons. Preliminary results also suggest that the ratio of F to G actin is skewed towards G actin in all mutants. The present results could have relevance to the loss of dopaminergic neurons in Parkinson’s disease.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004431, http://purl.flvc.org/fau/fd/FA00004431
- Subject Headings
- Aging -- Molecular aspects, Cellular signal transduction, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Mutation (Biology), Oxidative stress, Proteins -- Chemical modification
- 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
-
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
- Mitochondrial regulation pathways in the lens: pink1/parkin- and bnip3l-mediated mechanisms.
- Creator
- Aktan, Kerem, Kantorow, Marc, Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Biomedical Science
- Abstract/Description
-
The mitochondrion is the powerhouse of the cell. Therefore, it is critical to the homeostasis of the cell that populations of mitochondria that are damaged or in excess are degraded. The process of targeted elimination of damaged or excess mitochondria by autophagy is called mitophagy. In this report, analysis of the mitophagy regulators PINK1/PARKIN and BNIP3L and their roles are assessed in the lens. PARKIN, an E3 ubiquitin ligase, has been shown to play a role in directing damaged...
Show moreThe mitochondrion is the powerhouse of the cell. Therefore, it is critical to the homeostasis of the cell that populations of mitochondria that are damaged or in excess are degraded. The process of targeted elimination of damaged or excess mitochondria by autophagy is called mitophagy. In this report, analysis of the mitophagy regulators PINK1/PARKIN and BNIP3L and their roles are assessed in the lens. PARKIN, an E3 ubiquitin ligase, has been shown to play a role in directing damaged mitochondria for degradation. While BNIP3L, an outer mitochondrial membrane protein, increases in expression in response to excess mitochondria and organelle degradation during cellular differentiation. We have shown that PARKIN is both induced and translocates from the cytoplasm to the mitochondria in human epithelial lens cells upon oxidative stress exposure. In addition, our findings also show that overexpression of BNIP3L causes premature clearance of mitochondria and other organelles, while loss of BNIP3L results in lack of clearance. Prior to this work, PARKIN mediated mitophagy had not been shown to act as a protective cellular response to oxidative stress in the lens. This project also resulted in the novel finding that BNIP3L-mediated mitophagy mechanisms are required for targeted organelle degradation in the lens.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004427, http://purl.flvc.org/fau/fd/FA00004427
- Subject Headings
- Cellular signal transduction, Eye -- Diseases -- Etiology, Mitochondrial pathology, Mitophagy, Molecular chaperones, Oxidative stress -- Prevention, Protein folding
- Format
- Document (PDF)
- Title
- Developmental delays in methionine sulfoxide reductase mutants in Drosophila Melanogaster.
- Creator
- Hausman, William, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Aging is a biological process that has many detrimental effects due to the accumulation of oxidative damage to key biomolecules due to the action of free radicals. Methionine sulfoxide reductase (Msr) functions to repair oxidative damage to methionine residues. Msr comes in two forms, MsrA and MsrB, each form has been shown to reduce a specific enantiomer of bound and free oxidized methionine. Effects of Msr have yet to be studied in the major developmental stages of Drosophila melanogaster...
Show moreAging is a biological process that has many detrimental effects due to the accumulation of oxidative damage to key biomolecules due to the action of free radicals. Methionine sulfoxide reductase (Msr) functions to repair oxidative damage to methionine residues. Msr comes in two forms, MsrA and MsrB, each form has been shown to reduce a specific enantiomer of bound and free oxidized methionine. Effects of Msr have yet to be studied in the major developmental stages of Drosophila melanogaster despite the enzymes elevated expression during these stages. A developmental timeline was determined for MsrA mutant, MsrB mutant, and double null mutants against a wild type control. Results show that the Msr double mutant is delayed approximately 20 hours in the early/mid third instar stage while each of the single mutants showed no significant difference to the wild type. Data suggests that the reasoning of this phenomenon is due to an issue gaining mass.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004200, http://purl.flvc.org/fau/fd/FA00004200
- Subject Headings
- Aging -- Molecular aspects, Cellular signal transduction, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Mutation (Biology), Oxidative stress
- Format
- Document (PDF)
- Title
- Methionine sulfoxide reductase (Msr) deficiency leads to a reduction of dopamine levels in Drosophila.
- Creator
- Hernandez, Caesar, Binninger, David, Weissbach, Herbert, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Biological homeostasis relies on protective mechanisms that respond to cellular oxidation caused primarily by free radical reactions. Methionine sulfoxide reductases (Msr) are a class of enzymes that reverse oxidative damage to methionine in proteins. The focus of this study is on the relationship between Msr and dopamine levels in Drosophila. Dopaminergic neurons in Drosophila have comparable roles to those found in humans. A deficit in dopamine leads to the onset of many neurological...
Show moreBiological homeostasis relies on protective mechanisms that respond to cellular oxidation caused primarily by free radical reactions. Methionine sulfoxide reductases (Msr) are a class of enzymes that reverse oxidative damage to methionine in proteins. The focus of this study is on the relationship between Msr and dopamine levels in Drosophila. Dopaminergic neurons in Drosophila have comparable roles to those found in humans. A deficit in dopamine leads to the onset of many neurological disorders including the loss of fine motor control—a neurodegenerative condition characteristic of Parkinson’s disease (PD). We found that dopamine levels in the heads of MsrAΔ/ΔBΔ/Δ mutants are significantly reduced in comparison to MsrA ⁺/⁺ B⁺/⁺ heads. In addition, wefound protein and expression levels are markedly reduced in an Msr-deficient system. Our findings suggest an important role for the Msr system in the CNS.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004202, http://purl.flvc.org/fau/fd/FA00004202
- Subject Headings
- Cellular signal transduction, Dopamine -- Receptors, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Proteins -- Chemical modification
- Format
- Document (PDF)
- Title
- An investigation of membrane transporter proteins in the distal vertebrate retina: excitatory amino acid transporters and sodium potassium chloride cotransporters.
- Creator
- Purpura, Lauren Angeline, Shen, Wen, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Neurons are able to maintain membrane potential and synaptic integrity by an intricate equilibrium of membrane transporter proteins and ion channels. Two membrane proteins of particular importance in the vertebrate retina are the excitatory amino acid transporters (EAATs) which are responsible for the reuptake of glutamate into both glial and neuronal cells and the sodium potassium chloride cotransporters (NKCCs) that are responsible for the uptake of chloride ions into the cell. NKCCs are...
Show moreNeurons are able to maintain membrane potential and synaptic integrity by an intricate equilibrium of membrane transporter proteins and ion channels. Two membrane proteins of particular importance in the vertebrate retina are the excitatory amino acid transporters (EAATs) which are responsible for the reuptake of glutamate into both glial and neuronal cells and the sodium potassium chloride cotransporters (NKCCs) that are responsible for the uptake of chloride ions into the cell. NKCCs are electro-neutral with the uptake of 2 Cl- coupled to an exchange of a potassium and Na+ ion into the cells. Therefore, there is little change of cell membrane potential in the action of NKCCs. In this study the localization and function of EAATs in the distal retina is investigated. Whole cell patch clamp recordings in lower vertebrate retina have demonstrated that EAAT2 is the main synaptic EAATs in rod photoreceptors and it is localized to the axon terminals. Furthermore, the action of the transporter seems to be modified by intracellular calcium concentration. There is also evidence that EAAT2 might be regulated by feedback from the neuron network by glycinergic and GABAergic mechanisms. The second half of this study investigates expression of NKCCs in the retina by western blot analysis and quantitative polymerase chain reaction. There are two forms of NKCCs, NKCC1 and NKCC2. NKCC1 is mostly expressed in the central nervous system and NKCC2 was thought to only be expressed in the kidneys. NKCC1 is responsible for the majority of chloride uptake into neuronal and epithelial cells and NKCC1 is expressed in the distal retina where photoreceptors synapse on second order horizontal and bipolar cells. This study found the expression of NKCC1 in the distal retina to be regulated by temporal light and dark adaptation. Light adaptation increased phosphorylated NKCC1 expression (the active form of the cotransporter). The increase in NKCC1 expression during light adaptation was modulated by dopamine. Specifically, a D1 receptor agonist increased phosphorylated NKCC1 expression. Dopamine is an essential chemical and receptor known for initiating light adaptation in retina. Finally, an NKCC1 knockout mouse model was examined and it revealed that both forms of NKCC are expressed in the vertebrate retina.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004224, http://purl.flvc.org/fau/fd/FA00004224
- Subject Headings
- Biological transport, Carrier proteins, Cellular signal transduction, Neural receptors, Retina -- Cytology
- Format
- Document (PDF)
- Title
- Functional roles of L1-Cam/Neuroglian in the nervous system of Drosophila Melanogaster.
- Creator
- Kudumala, Sirisha, Godenschwege, Tanja A., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
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Neuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic...
Show moreNeuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic connectivity to control the development and maintenance of synaptic connections within neuronal circuits. Here we characterized the essential role of nrg in regulating synaptic structure and function in vivo in a well characterized Drosophila central synapse model neuron, the Giant Fiber (GF) system. Previous studies from our lab revealed that the phosphorylation status of the tyrosine in the Ankyrin binding FIGQY motif in the intracellular domain of Nrg iscrucial for synapse formation of the GF to Tergo-Trochanteral Motor neuron (TTMn) synapse in the GF circuit. The present work provided us with novel insights into the role of Nrg-Ank interaction in regulating Nrg function during synapse formation and maintenance. By utilizing a sophisticated Pacman based genomic rescue strategy we have shown that dynamic regulation of the Neuroglian–Ankyrin interaction is required to coordinate transsynaptic development in the GF–TTMn synapse. In contrast, the strength of Ankyrin binding directly controls the balance between synapse formation and maintenance at the NMJ. Human L1 pathological mutations affect different biological processes distinctively and thus their proper characterization in vivo is essential to understand L1CAM function. By utilizing nrg14;P[nrg180ΔFIGQY] mutants that have exclusive synaptic defects and the previously characterized nrg849 allele that affected both GF guidance and synaptic function, we were able to analyze pathological L1CAM missense mutations with respect to their effects on guidance and synapse formation in vivo. We found that the human pathological H210Q, R184Q and Y1070C, but not the E309K and L120V L1CAM mutations affect outside-in signaling via the FIGQY Ankyrin binding domain which is required for synapse formation and not for axon guidance while L1CAM homophilic binding and signaling via the ERM motif is essential for axon guidance in Drosophila.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004131, http://purl.flvc.org/fau/fd/FA00004131
- Subject Headings
- Cell adhesion molecules, Cellular signal transduction, Cognitive neuroscience, Cognitive neuroscience, Drosophila melanogaster, Molecular neurobiology
- 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
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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.
Show less - 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
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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)
- Title
- Evaluation of marine sponge metabolites for cytotoxicity and signal transduction activity.
- Creator
- Longley, Ross E., McConnell, O. J., Essich, E., Harmody, Dedra K., Harbor Branch Oceanographic Institute
- Date Issued
- 1993
- PURL
- http://purl.flvc.org/FCLA/DT/3318961
- Subject Headings
- Marine metabolites, Sponges --Research, Cell-mediated cytotoxicity, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Heterologous expression and purification of cell function components -: an effort towards developing an antigen-capture ELISA diagnostics for metastatic cancers.
- Creator
- Irvine, Michael., Charles E. Schmidt College of Medicine, Department of Biomedical Science
- Abstract/Description
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Metastatic cancers are problematic because they spread throughout the body. A crucial step in cancer metastasis is the separation of the cancer cells from their surrounding normal cells. This occurs due to suppression or destruction of cell adhesion molecules such as E-cadherin, occludin, and various claudins. The Snail and Slug transcription factors play a direct role in suppressing these cell adhesion molecules through their SNAG repression domain. We explored the possibility of developing...
Show moreMetastatic cancers are problematic because they spread throughout the body. A crucial step in cancer metastasis is the separation of the cancer cells from their surrounding normal cells. This occurs due to suppression or destruction of cell adhesion molecules such as E-cadherin, occludin, and various claudins. The Snail and Slug transcription factors play a direct role in suppressing these cell adhesion molecules through their SNAG repression domain. We explored the possibility of developing an ELISA diagnostics capable of detecting soluble E-cadherin, occludin, and claudin fragments in the serum of cancer patients. Using several bioinformatics tools, unique extracellular antigenic sequences were identified on claudins-1, 4, 16, occludin, and E-cadherin. These sequences were cloned as GST fusion proteins, expressed, and purified in large quantities to raise antibodies. In parallel, expression profiling of metastatic cancer cell lines was carried out to derive a correlation between Snail-Slug expression and suppression of cell adhesion molecules.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/369191
- Subject Headings
- Cellular signal transduction, Extracellular matrix proteins, Genetic transcription, Research, Metalloproteinases, Inhibitors
- 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)