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Articles 1 - 18 of 18
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Homologous Neurons And Their Locomotor Functions In Nudibranch Molluscs, James M. Newcomb
Homologous Neurons And Their Locomotor Functions In Nudibranch Molluscs, James M. Newcomb
Biology Dissertations
These studies compare neurotransmitter localization and the behavioral functions of homologous neurons in nudibranch molluscs to determine the types of changes that might underlie the evolution of species-specific behaviors. Serotonin (5-HT) immunohistochemistry in eleven nudibranch species indicated that certain groups of 5 HT-immunoreactive neurons, such as the Cerebral Serotonergic Posterior (CeSP) cluster, are present in all species. However, the locations and numbers of many other 5 HT-immunoreactive neurons were variable. Thus, particular parts of the serotonergic system have changed during the evolution of nudibranchs. To test whether the functions of homologous neurons are phylogenetically variable, comparisons were made in species …
Septal Infusions Of The H-Channel Blocker Zd7288 Impair Spontaneous Alternation But Not Inhibitory Avoidance, Ramata Sissoko Cisse
Septal Infusions Of The H-Channel Blocker Zd7288 Impair Spontaneous Alternation But Not Inhibitory Avoidance, Ramata Sissoko Cisse
Biology Theses
It is well established that the septo-hippocampal system is involved in memory. The medial septum is connected to the hippocampus via the fimbria fornix, which consists mostly of acetylcholine and ã-aminobutyric acid (GABA) projection neurons. The contributions of the cholinergic projection to memory have been studied extensively; whereas, the role of the GABAergic projection is not well characterized. The present experiment tested whether septal infusions of the selective H-channel blocker ZD7288 would impair spontaneous alternation (SA) and continuous multiple inhibitory avoidance (CMIA). Fifteen minutes prior to assessing SA or CMIA, different groups of male Sprague-Dawley rats were given septal infusions …
Isolation And Characterization Of The Y32g9a.8 Promoter In C. Elegans, Rebecca Joy Schlisner
Isolation And Characterization Of The Y32g9a.8 Promoter In C. Elegans, Rebecca Joy Schlisner
Biology Theses
The over-expression of Down syndrome cell adhesion molecules (DSCAMs) is partially responsible for the mental retardation associated with Down syndrome. Previous work in our lab showed that a DSCAM homolog in C. elegans, Y32G9A.8, is expressed at all developmental stages and appears to be crucial for survival. In an effort to map the expression pattern, I used the Genome Sciences Centre’s primer design program (http://elegans.bcgsc.bc.ca/gfp_primers/) to design a GFP promoter fusion product that was used to monitor gene expression. The results indicate that Y32G9A.8 is expressed in the animal’s gut, suggesting that it may function in the worm’s innate immune …
The Role Of S7, A Subunit Of The 19s Proteasome, In The Transcriptional Regulation Of Mhc Ii., Dawson Gerhardt
The Role Of S7, A Subunit Of The 19s Proteasome, In The Transcriptional Regulation Of Mhc Ii., Dawson Gerhardt
Biology Theses
Induction of an adaptive, or antigen specific, immune response is critical for eliminating most infections. Pathogen clearance is accomplished primarily, by the actions of CD4+ T cells through their ability to recognize foreign antigens presented at the cell surface by major histocompatibility class II (MHC II) molecules. Consequently, the capacity to regulate expression of MHC molecules is essential to control the adaptive immune response. MHC molecules are regulated at the level of transcription by a master regulator, the class II transcriptional activator, CIITA. Thus, the expression of MHC II is directly related to proper CIITA activity. This thesis focuses on …
An Integrative Analysis Of Reproduction And Stress In Free-Living Male Cottonmouths, Agkistrodon Piscivorus, Sean Patrick Graham
An Integrative Analysis Of Reproduction And Stress In Free-Living Male Cottonmouths, Agkistrodon Piscivorus, Sean Patrick Graham
Biology Theses
I conducted an integrative field study on male cottonmouths (Agkistrodon piscivorus), a common pitviper of the southeastern United States, to investigate the evolution of contrasting mating patterns in North American pitvipers (bimodal and unimodal annual patterns) and resolve conflicting information about the pattern exhibited by the cottonmouth. I determined a unimodal late summer peak of testosterone (T) and a muted unimodal seasonal cycle of the sexual segment of the kidney (a secondary sexual characteristic), both of which were correlated with the single peak of spermatogenesis in late summer. I also conducted a study to determine diel and seasonal variation of …
Investigation Into The Mechanism(S) Which Permit The High-Rate, Degradation Of Pahs And Related Petroleum Hydrocarbons In Sequencing Batch Reactors By Attached Cells In A Controlled Mixed Bacterial Community., Emad Ibraheim Hussein
Biology Dissertations
A stable mixed culture, deposited as ATCC 55644, previously shown to degrade petroleum hydrocarbons at relatively high concentrations was used as the source of inoculum. This culture was grown in Stanier’s minimal media, either in the presence of different concentrations of naphthalene, nitrobenzene and toluene (NNT) or naphthalene and toluene (NT) as the sole source of C and/or N. Results showed that the majority of the strains isolated from the mixed culture were able to grow in the presence of NNT or NT. A total of 20 different isolates were isolated from the mixed culture. Individual isolates were grown in …
The Role Of Ecological Interactions In Polymicrobial Biofilms And Their Contribution To Multiple Antibiotic Resistance, Heather Adele O'Connell
The Role Of Ecological Interactions In Polymicrobial Biofilms And Their Contribution To Multiple Antibiotic Resistance, Heather Adele O'Connell
Biology Dissertations
The primary objectives of this research were to demonstrate that: 1.) antibiotic resistant bacteria can promote the survival of antibiotic sensitive organisms when grown simultaneously as biofilms in antibiotics, 2.) community-level multiple antibiotic resistance of polymicrobial consortia can lead to biofilm formation despite the presence of multiple antibiotics, and 3.) biofilms may benefit plasmid retention and heterologous protein production in the absence of selective pressure. Quantitative analyses of confocal data showed that ampicillin resistant organisms supported populations of ampicillin sensitive organisms in steady state ampicillin concentrations 13 times greater than that which would inhibit sensitive cells inoculated alone. The rate …
Neurolipofuscin Is A Measure Of Age In The Caribbean Spiny Lobster, Panulirus Argus, In Florida, Kerry Elizabeth Maxwell
Neurolipofuscin Is A Measure Of Age In The Caribbean Spiny Lobster, Panulirus Argus, In Florida, Kerry Elizabeth Maxwell
Biology Theses
Accurate age estimates for the commercially-important Caribbean spiny lobster, Panulirus argus, would greatly enhance analyses of life history and population dynamics. Previous estimates of their age based on size and growth may be inaccurate because of variable growth in the wild. An established technique for aging crustaceans – histologically-determined lipofuscin content in the nervous system – was used on lobsters reared in the laboratory for up to five years. We verified the presence of lipofuscin in eyestalk neural tissue and described its distribution in cell cluster A of the hemiellipsoid body. Neurolipofuscin content of both sexes increased linearly over the …
Steroid Sensitive Neurons And Male Rat Mating Behavior, Gloria Gradine Huddleston
Steroid Sensitive Neurons And Male Rat Mating Behavior, Gloria Gradine Huddleston
Biology Dissertations
Male rat mating is a suite of individual behaviors mediated by the actions of two metabolites of testosterone (T), dihydrotestosterone (DHT) and estradiol (E2), on the brain. Individually, neither metabolite fully maintains or restores mating in castrated males, but both combined are as effective as T. Two hormone-responsive areas of the brain, the medial preoptic area (MPO) and the medial amygdala (MEA), are crucial for mating. These studies ask: by what mechanism(s) does E2 act in the MPO and MEA? We blocked the conversion of T to E2 in the MEA of intact male rats and sexual behavior was not …
Functional Role Of Dead-Box P68 Rna Helicase In Gene Expression, Chunru Lin
Functional Role Of Dead-Box P68 Rna Helicase In Gene Expression, Chunru Lin
Biology Dissertations
How tumor cells migrate and metastasize from primary sites requires four major steps: invasion, intravasation, extravasation and proliferation from micrometastases to malignant tumor. The initiation of tumor cell invasion requires Epithelial-Mesenchymal Transition (EMT), by which tumor cells lose cell-cell interactions and gain the ability of migration. The gene expression profile during the EMT process has been extensively investigated to study the initiation of EMT. In our studies, we indicated that tyrosine phosphorylation of human p68 RNA helicase positively associated with the malignant status of tumor tissue or cells. Studying of this relationship revealed that p68 RNA helicase played a critical …
Identification And Functional Analysis Of Crustacean Serotonin Receptors., Nadja Spitzer
Identification And Functional Analysis Of Crustacean Serotonin Receptors., Nadja Spitzer
Biology Dissertations
Constantly changing environments force animals to adapt by cycling through multiple physiological states. Plasticity in sensory, motor, and modulatory neural circuits is an essential part of these adaptive processes. Invertebrates with their accessible, identifiable neurons are excellent models for investigating the molecular and cellular mechanisms underlying state-dependent neural plasticity, and provide insight into similar processes in more complex systems. These properties have allowed highly detailed characterization of several crustacean circuits with respect to their connectivities, cellular properties, responses to various inputs, and outputs. Serotonin (5-HT) is an important neuromodulator in virtually every animal species. 5-HT signals are mediated primarily by …
Chemosensory Responses In Azospirillum Brasilense, Bonnie Baggett Stephens
Chemosensory Responses In Azospirillum Brasilense, Bonnie Baggett Stephens
Biology Dissertations
The ability to swim and navigate the surrounding environment confers an advantage to motile bacteria, allowing the occupation of niches that are optimum for survival and growth. Bacteria are too small to sense their environment spatially, so they must sense the environment temporally by comparing the past and present environments and altering their motility accordingly. Chemotaxis systems coordinate flagellar motility responses with temporal sensing of the environment. Chemotaxis is proposed to be involved in plant root colonization by directing soil bacteria toward root exudates of various cereals, promoting growth. The nitrogen-fixing alpha-proteobacterium Azospirillum brasilense utilizes chemotaxis to navigate its environment …
Immunoglobulins And Immunoglobulin Fc Receptors In Nonhuman Primates Commonly Used In Biomedical Research, Kenneth Alton Rogers
Immunoglobulins And Immunoglobulin Fc Receptors In Nonhuman Primates Commonly Used In Biomedical Research, Kenneth Alton Rogers
Biology Dissertations
Antibodies neutralize and eliminate pathogens, malignancies, and toxins by acting either alone or in association with Fc receptors which, once engaged, activate the elimination mechanisms of phagocytic cells. Based on structural differences, antibodies are divided into functionally distinct classes (IgM, IgD, IgG, IgE and IgA). Structure-function relationships within these classes are not well characterized. In addition, animal models for the assessment of potential therapeutic strategies for the modulation of the interaction between antibodies and Fc receptors are not established. Nonhuman primates are widely used to model human diseases and, represent excellent in vivo systems for this assessment. Therefore, we have …
Social Status-Dependent Changes In Behavior And Neurogenesis In The Crayfish Procambarus Clarkii, Cha-Kyong Song
Social Status-Dependent Changes In Behavior And Neurogenesis In The Crayfish Procambarus Clarkii, Cha-Kyong Song
Biology Dissertations
Crayfish (Procambarus clarkii) form dominance hierarchies, which are patterns of repeated fights with expected outcomes of winner and loser. Establishment of hierarchies allows dominants the first access to limited resources over subordinates, and leads to behavioral and cellular changes corresponding to the social status. Here, the animals¡¯ responses to an unexpected unilateral touch, a non-social stimulus, were examined with respect to their social status and to their social context. Isolates oriented to the stimulus source with raised claws and elevated posture. Dominants also oriented to the stimulus both when tested alone and in the presence of a subordinate. Subordinates oriented …
The Role Of Autoinducer-2 In Escherichia Coli Biofilm Formation And The Discovery Of A Plant-Derived Quorum Sensing Inhibitor, Chen Niu
Biology Dissertations
The objectives of this work are: 1) to determine whether plant essential oil components influence the ability of Escherichia coli and several Pseudomonas species to form biofilms, and inhibit bacterial quorum sensing; 2) to understand the role of autoinducer-2 (AI-2) in biofilm formation by E. coli W3110. The biofilm formation assays determined that cinnamon, cassia and citronella oils differentially affected growth-normalized biofilm formation by E. coli. Cinnamaldehyde (CA) also inhibited the swimming motility of E. coli. Subinhibitory concentrations of CA were effective at inhibiting two types of acyl homoserine lactone (HSL) mediated quorum sensing (QS), and also AI-2 mediated QS. …
Age And Sex Differences In The Acquisition And Maintenance Of Intravenous Amphetamine Self-Administration In Rats, Mahin Shahbazi
Age And Sex Differences In The Acquisition And Maintenance Of Intravenous Amphetamine Self-Administration In Rats, Mahin Shahbazi
Biology Theses
Drug abuse peaks during adolescence, and exposure to drugs during adolescence predicts drug abuse in adulthood. Nevertheless, adolescence is not widely studied in animal models of drug intake. Moreover, few studies have investigated sex differences in drug-reinforced behavior during adolescence. We studied age- and sex-differences in acquisition and maintenance of amphetamine self-administration in Sprague-Dawley rats. Adolescent males took more amphetamine than adult males, supporting the hypothesis that adolescents are more sensitive to amphetamine. A high rate of “inappropriate” active lever presses among periadolescent males suggests impulsive behavior. In the maintenance phase of testing, young adult males failed to work as …
An Examination Of The Human Fibrinogen-Like Protein2: Sequence Variations And Genetic Expression By Human Endothelial Cells, Meredith E. Jenkins
An Examination Of The Human Fibrinogen-Like Protein2: Sequence Variations And Genetic Expression By Human Endothelial Cells, Meredith E. Jenkins
Biology Theses
A role for Fgl2 (fibroleukin) in thrombophilic-associated human fetal loss has been indicated by previous studies. Clotting of vascular vessels of the placenta and fetus interferes with adequate blood circulation. The human Fgl2 gene was sequenced with identification of six SNPs, suggesting an association with a population of women suffering from recurrent fetal losses. A small sample size however, prevented precise statistical analyses of this association. In vitro, human endothelial cells (HUVECs) were not found to constitutively express Fgl2, but were shown to up-regulate its expression when challenged with IFN-γ and TNF-α. Interestingly, TNF-α was only shown to induce expression …
The Role Of The Sia And Siu Abc-Type Transporters In Iron Utilization And Virulence In Streptococcus Pyogenes, Griselle Enid Montanez
The Role Of The Sia And Siu Abc-Type Transporters In Iron Utilization And Virulence In Streptococcus Pyogenes, Griselle Enid Montanez
Biology Dissertations
A limited understanding of iron uptake mechanisms is available for Streptococcus pyogenes, a hemolytic human pathogen capable of using a variety of hemoproteins in addition to ferric and ferrous iron. This study characterizes the transporters of iron-complexes siuADBG (for streptococcal iron uptake) and siaABC (for streptococcal iron acquisition). These ABC-type transporters are encoded by iron regulated operons and their protein products are homologous to components of heme and siderophore transporters found in both Gram-positive and Gram-negative bacteria. Mutants of the membrane permeases siuG and siaB were constructed and characterized. Mutations in both transporters demonstrated growth reduction in comparison to the …