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Assessment Of Arbuscular Mycorrhizal Symbiosis On Invasion Success In Brachypodium Sylvaticum, Caitlin Elyse Lee Nov 2014

Assessment Of Arbuscular Mycorrhizal Symbiosis On Invasion Success In Brachypodium Sylvaticum, Caitlin Elyse Lee

Dissertations and Theses

The effects that mutualistic soil biota have on invasive species success is a growing topic of inquiry. Studies of the interactions between invasive plants and arbuscular mycorrhizal fungi (AMF) have shown changes in AMF community composition, reductions in AMF associations in invasive plants, and changes in native species fitness and competitive outcomes in invasive-shifted AMF communities. These findings support the degraded mutualist hypothesis, where invasive species alter the mutualist community composition, resulting in detrimental associations with the new mutualist community for native species. Here I present two studies that examine various aspects of the arbuscular mycorrhizal fungal (AMF) mutualism in …


Characterization Of Functional Domains Of Cul3, An E3 Ubiquitin Ligase, Using Chimeric Analysis, Jennifer Anne Mitchell Sep 2014

Characterization Of Functional Domains Of Cul3, An E3 Ubiquitin Ligase, Using Chimeric Analysis, Jennifer Anne Mitchell

Dissertations and Theses

Modification of cellular proteins with molecules of ubiquitin is an important process that regulates the activity of cellular proteins. Cullin RING ligases (CRLs) are multi-subunit complexes that act in concert with E2 enzymes to attach molecules of ubiquitin to protein substrates. There are seven CRLs in mammalian cells (Cul1, Cul2, Cul3, Cul4A, Cul4B, Cul5, and Cul7) that are highly homologous in sequence and structure. CRLs possess a highly conserved C- terminal domain that interacts with E2 enzymes, and a more variable N- terminal domain which recruits substrates through distinct substrate adapter molecules. Despite the structural similarity, these CRLs recognize distinct …


The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai Jul 2014

The Orientation Of The Pyrococcus Furiosus Transcription Factor Tfb2 In The Transcription Initiation Complex, Arati Bhattarai

Dissertations and Theses

The hyperthermophile archaeon, Pyrococcus furiosus encodes two eukaryotic TFIIB family proteins, TFB1 and TFB2. TFB1 is very similar to TFIIB in terms of sequence homology and function, whereas TFB2 is unusual as it is missing highly conserved sequences in its N-terminal domain that are present in TFIIB and TFB1. Despite this, TFB2 is effective in transcription process, albeit with lower efficiency compared to TFB1. Other archaea also contain multiple TFBs, but unlike Pyrococcus furiosus TFB2, these multiple TFBs have higher sequence homology to each other and have similar transcription efficiencies. Photochemical cross-linking experiments have shown that the B-reader of TFB …


Temperature Dependent Transcription Initiation In Archaea: Interplay Between Transcription Factor B And Promoter Sequence, Ming-Hsiao Wu May 2014

Temperature Dependent Transcription Initiation In Archaea: Interplay Between Transcription Factor B And Promoter Sequence, Ming-Hsiao Wu

Dissertations and Theses

In Pyrococcus furiosus (Pfu), a hyperthermophile archaeon, two transcription factor Bs, TFB1 and TFB2 are encoded in the genomic DNA. TFB1 is the primary TFB in Pfu, and is homologous to transcription factor IIB (TFIIB) in eukaryotes. TFB2 is proposed to be a secondary TFB that is compared to TFB1, TFB2 lacks the conserved B-finger / B-reader / B-linker regions which assist RNA polymerase in transcription start site selection and promoter opening functions respectively. P. furiosus, like all Archaea, encodes a single transcription factor E (TFE), that is homologous to the N-terminus of transcription factor II …


Chytrid Loads, Pathogen Prevalence, And Contemporary Host Source-Sink Dynamics In Dry Vs. Wet Forests; Evaluating Refugia From Disease In Australian Torrent Frogs., Barbara Rizzo Jan 2014

Chytrid Loads, Pathogen Prevalence, And Contemporary Host Source-Sink Dynamics In Dry Vs. Wet Forests; Evaluating Refugia From Disease In Australian Torrent Frogs., Barbara Rizzo

Dissertations and Theses

No abstract provided.


The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro Jan 2014

The Impact Of Saccadic Eye Movement Training On Saccade Accuracy And Latency, Stephanie Montenegro

Dissertations and Theses

No abstract provided.


Kos Modulation Of Mitochondrial Fission And Fusion, Herman Kucharavy Jan 2014

Kos Modulation Of Mitochondrial Fission And Fusion, Herman Kucharavy

Dissertations and Theses

No abstract provided.


Structure-Function Analysis Of Zapc, An Ftsz-Ring Stabilizer, In Escherichia Coli Cytokinesis, Lukasz Tchorzewski Jan 2014

Structure-Function Analysis Of Zapc, An Ftsz-Ring Stabilizer, In Escherichia Coli Cytokinesis, Lukasz Tchorzewski

Dissertations and Theses

In Escherichia coli, cell division is defined by the polymerization and constriction of a cytokinetic ring (Z ring) formed by FtsZ, a tubulin-like GTPase, at midcell. Division also involves the formation of a multi-protein complex at midcell known as the divisome. Several divisome proteins promote the assembly/disassembly processes of FtsZ, thereby exercising spatiotemporal control over division. Among FtsZ regulatory proteins are the FtsZ ringassociated proteins (Zap), which either directly or indirectly stabilize the Z-ring by increasing lateral interactions amongst FtsZ protofilaments in the Z-ring. ZapA-D are recruited during early cytokinesis and have overlapping functions in stabilizing FtsZ at midcell, but …


Investigating Innate Immune Signaling Cross-Talk In A Drosophila Tumor-Inflammation Model, Rebecca Moore Jan 2014

Investigating Innate Immune Signaling Cross-Talk In A Drosophila Tumor-Inflammation Model, Rebecca Moore

Dissertations and Theses

No abstract provided.


Methodological Advancements For Improving Performance And Generating Ensemble Ecological Niche Models, Robert Boria Jan 2014

Methodological Advancements For Improving Performance And Generating Ensemble Ecological Niche Models, Robert Boria

Dissertations and Theses

This study employs spatial filtering of occurrence data with the aim of reducing overfitting to sampling bias in ecological niche models (ENMs). Sampling bias in geographic space leads to localities that may also be biased in environmental space. If so, the model can overfit to those biases. As a preliminary test addressing this issue, we used Maxent, bioclimatic variables, and occurrence localities of a broadly distributed Malagasy tenrec, Microgale cowani (Family Tenrecidae: Subfamily Oryzorictinae). We modeled the abiotically suitable area of this species using three distinct datasets: unfiltered, spatially filtered, and rarefied unfiltered localities. To quantify overfitting and model performance, …


Screen For Suppressors And Enhancers Of Excitotoxic Neurodegeneration, Anthony Omorodion Edokpolo Jan 2014

Screen For Suppressors And Enhancers Of Excitotoxic Neurodegeneration, Anthony Omorodion Edokpolo

Dissertations and Theses

Excitotoxicity is an important and frequently observed neurodegenerative process. Excitotoxicity mediates brain damage in a range of diseases and conditions including stroke, and is triggered by excessive stimulation of glutamatergic synapses. In spite of extensive studies, the molecular mechanisms involved in excitotoxicity following the over-activation of postsynaptic glutamate receptors are not well understood, and clinical trials based on our partial understanding of the process ended with disappointment. Genetic screens in simple animal models offer a powerful alternative approach, since screens are unbiased, analysis is facilitated by strong research tools, and cellular mechanisms are highly conserved through evolution. We produced a …


Caffeine's Attenuation Of Cocaine-Induced Deficiency In Acoustic Startle Response By Inhibition Of Adenosine In A Sex And Dose Dependent Manner, Lauren B. Malave Jan 2014

Caffeine's Attenuation Of Cocaine-Induced Deficiency In Acoustic Startle Response By Inhibition Of Adenosine In A Sex And Dose Dependent Manner, Lauren B. Malave

Dissertations and Theses

No abstract provided.


Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong Jan 2014

Synaptic Physiology Of Glutamate Clearance In The Nematode Caenorhabditis Elegans, Jenny (Chan Ying) Wong

Dissertations and Theses

No abstract provided.


A Phylogeographic Study Of Two Neotropical Bird Species, The Red-Headed Manakin (Pipna Rubrocapilla) And The White-Crowned Manakin (Dixiphia Pipra)., Ivandy Castro-Astor Jan 2014

A Phylogeographic Study Of Two Neotropical Bird Species, The Red-Headed Manakin (Pipna Rubrocapilla) And The White-Crowned Manakin (Dixiphia Pipra)., Ivandy Castro-Astor

Dissertations and Theses

No abstract provided.


Experimental Studies Of Rctb- Initiator Of Vibrio Cholerae Chromosome Ii Replication: Genetic Engineering, Protein Purification, And Protein Crystals, Olha Ivashkiv Jan 2014

Experimental Studies Of Rctb- Initiator Of Vibrio Cholerae Chromosome Ii Replication: Genetic Engineering, Protein Purification, And Protein Crystals, Olha Ivashkiv

Dissertations and Theses

Vibrio cholerae, a member of the Vibrionaceae family, is notorious as the causative agent of acute gastrointestinal disease known as cholera. Genetic information in members of the Vibrionaceae family is distributed between two chromosomes that are distinctively maintained. In V. cholerae, the initiation of DNA replication in each chromosome involves distinct processes. While the initiation of replication of chromosome I is carried by DnaA, the initiation of chromosome II replication is controlled by RctB, a DNA-binding protein that is an exclusive attribute of all Vibrio species. RctB has no homologs among other members of bacteria proteins and can serve as …