Molecular Biology Commons^™

Minimal Carbon Requirements For Potential Colonizers Of Other Planets, Benjamin Tan

Biological Sciences Undergraduate Honors Theses

The NASA Office of Planetary Protection regulates the safe scientific exploration of other planets. Specifically, the office enacts rules to discourage interplanetary mission practices that would lead to the contamination of Earth-originating microbial life on other planets. Interplanetary contamination jeopardizes the potential to obtain reliable scientific evidence for extraterrestrial life. In coordination with this office, the biosignatures of potential colonizers of other celestials bodies are studied. Several organisms of Earth qualify as potential colonizers of other planets.

This experiment focused on the environment of Mars in particular. Two organisms were tested: Desulfovibrio arcticus and Desulfotalea psychrophila. Both are psychrotolerant or …

Validation Of Whole Genome Resequencing For Mapping The Genetics Of Ascites In Broilers And Viral Susceptibility In Layers, Katherine Pepper Lee

Graduate Theses and Dissertations

This dissertation focused on the efficacy and validity of whole genome resequencing (WGR) for fine mapping genetic determinants of particular traits in a given organism. Previously, our research group used WGR to identify haplotype blocks of single nucleotide polymorphisms associated with ascites resistance with some as strong candidates for use in marker-assisted selection (MAS). Chapter 2 discusses the completion of a MAS project through evaluation of ascites incidence as well as production traits of economic value to poultry producers. Thus, the MAS project also covered viability of this methodology in the industry. The MAS significantly reduced ascites incidence in broilers …

Mechanisms Of Telomere Maintenance In Trypanosoma Brucei, M A G G. Rabbani

ETD Archive

Telomeres are a nucleoprotein structure at the end of the chromosome and are essential for genome integrity and chromosome stability. Telomere lengths are primarily maintained by a telomerase-mediated pathway but can be maintained by a homologous recombination-mediated pathway. However, detailed mechanisms of telomere maintenance are still unclear in many eukaryotes, including an important human pathogen, Trypanosoma brucei. Telomeres can be elongated by telomerase in T. brucei, a causative agent of fatal sleeping sickness in humans and nagana in cattle. T. brucei evades host immune response by regularly switching its major surface antigen, variant surface glycoprotein (VSG), a process known as …

Halogen Bonding: A Computational Chemistry Investigation Of The Interaction Between Thyroid Hormone And Deiodinase, William Rice

Honors Theses

Halogen bonding is a noncovalent interaction that continues to garner interest among the scientific community. Investigation of halogen bonds in biological contexts typically revolves around rational drug design for developing therapeutics. However, halogen bonding may be occurring naturally in our body every day. Thyroid hormone and its regulating enzyme, iodothyronine deiodinase, show promising results for a halogen bonding interaction that happens during catalysis. Prior work has examined the interaction between the iodine of thyroid hormone and the selenium of iodothyronine deiodinase. However, this study is the first of its kind to use computational chemistry methods to analyze the halogen bond …

Microbial Community Analysis: Biofilm Inhibition & Algae Associated Community Structure, Michelle V. Fong

University of the Pacific Theses and Dissertations

Natural products chemistry is the pursuit of bioactive small molecules from living organisms. These can be classified as primary metabolites if they are essential to survival, and secondary metabolites if they are accessory, playing a role in communication, defense, recruitment, etc.. Natural products have made a significant contribution to society – of 1,881 FDA-approved drugs from 1981 to 2019, 4% were pure natural products, 19% were natural products derived, and 3% were synthetic drugs with a natural products pharmacophore targeting a wide range of diseases and infections (Newman & Cragg, 2020). Pharmacophores are structural components of drugs that are responsible …

Mechanisms Of Substrate Recognition By The Cul3-Based E3 Ligase, Katia Graziella De Oliveira Rebola

Dissertations and Theses

Cul3-based E3 ligase is responsible for regulating a variety of cellular pathways, many of which are known to have profound effects on the proper function of multicellular organisms. Although progress over the past years has been truly impressive, our understanding of the mechanisms of E2 recruitment and selection by the BCR complex and all the roles that Cul3 plays on kidneys remains in its infancy. To explore these aspects, this dissertation aims to analyze the Cul3 complex using two different approaches: (1) We used the powerful tool of chimeric analysis to map the essential domain binding characteristics of Cul3 taking …

Fxs-Causing Point Mutations In Fmrp Disrupt Neuronal Granule Formation And Function, Emily L. Starke

Electronic Theses and Dissertations

Fragile X Syndrome (FXS) is a neurodevelopmental disorder caused by the disruption of Fragile X Mental Retardation Protein (FMRP) function in neurons, affecting nearly 1 in 7,500 individuals. Although FXS typically occurs from a complete loss of FMRP expression due to a CGG trinucleotide expansion within the 5’UTR of the FMR1 gene, single nucleotide polymorphisms (SNPs) within the KH domains of FMRP have been shown to severely disrupt FMRP function. FMRP is an RNA-binding translation repressor that interacts with ~4% of the neuronal transcriptome. Many target mRNAs encode for proteins important for regulating synaptic processes and modulate synaptic plasticity. It …

Post-Translational Modification And Degradation Mechanisms Of The Aryl Hydrocarbon Receptor, Yujie Yang

University of the Pacific Theses and Dissertations

The aryl hydrocarbon receptor (AHR) is a transcription factor first discovered to be activated by exogenous ligands, such as dioxins, and helps promote downstream gene (e.g. CYP1A1) transcription to metabolize the toxicants. With the reports of various AHR targets genes, the expression levels and activities of AHR have been implicated in many physiological and pathological situations. Understanding how AHR protein level is regulated would provide more information to target AHR. AHR stays in the cytosol in the absence of ligand in a complex with HSP90, p23 and XAP2. After ligand activation, AHR translocates into the nucleus, fulfilling its transactivation function …

Development Of Linked-Domain Protein Inhibitors Of The E2-Conjugating Enzyme Ube2d, Anneroos E. Nederstigt

University of the Pacific Theses and Dissertations

In most eukaryotic organisms, the ubiquitination pathway is one of the most important and versatile signaling systems in use. It is integral to processes such as protein degradation and homeostasis, DNA repair cell cycle regulation, signaling and regulation, epigenetics, and many more. Ubiquitin (Ub) is a short polypeptide of 8.6 kDa, 76 residues that functions as a reversible post-translation modification (PTM). It furthermore contains 7 different lysine residues (K6, K11, K27, K29, K33, K48, K63), all of which can form isopeptide linkages with one another to link individual Ub moieties to form unique polyUb chains onto substrates. The type of …

Determining A Method For Expressing And Purifying Cytochrome P450 4v2: A Protein Involved In Bietti's Crystalline Dystrophy, Cody Lane Turner

MSU Graduate Theses

Within the Cytochrome P450 class of enzymes, there are a group known as the “orphan” cytochromes. The “orphan” classification comes from the poorly understood in vivo functionality and substrate specificity. Cytochrome P450 4V2 (CYP4V2) is one of these “orphans” and belongs to the CYP4 family. The CYP4 family is known for the omega oxidation of endogenous fatty acids. This family is most commonly found on chromosome 1 (CYP4ABXZ). CYP4V2 is unique in that its location is bound to chromosome 4 as discovered by Jiao in 2004. Mutations within the CYP4V2 gene have been associated with the …

Changes In Gene Expression Profiles In Müller Glia Following Exposure To An Α7 Nicotinic Acetylcholine Receptor Agonist, Megan L. Stanchfield

Masters Theses

Previous studies from this lab have determined that dedifferentiation of Müller glia (MG) occurs after application of an α7 nicotinic acetylcholine receptor agonist, PNU-282987 (PNU), to retinal pigment epithelial (RPE) cells in adult rodents. This study was designed to explore the role of the HB-EGF/Ascl1/Lin28a signaling pathway in MG dedifferentiation to retinal progenitor cells. RNAseq was performed on MG following contact with RPE-J cells treated with PNU-282987. Up- or down-regulated genes were compared with published literature of MG dedifferentiation that occurs in lower vertebrate regeneration or with transcript profiles during early mammalian development. Between 8-12 hours, up-regulation was observed in …

Iron-Sulfur Cluster Assembly; In Vivo Analysis Of The Methanogenic Suf System, Evan Dunkle

LSU Master's Theses

Iron-sulfur (Fe-S) clusters are among the most ancient and prevalent of all biological cofactors. Their assembly into associated proteins is a tightly regulated process with many organisms employing multiple cluster assembly pathways. Much is known about Fe-S cluster assembly in aerobic organisms such as Escherichia coli (E. coli) but little is known in regards to cluster assembly in more ancient organisms such as methanogens. Methanogens are members of the domain of Archaea and are defined by their ability to generate methane as a byproduct of their main energy generating pathway. Methanogens also have significantly higher Fe-S cluster content …

Evaluating Methods Of Obtaining Male Pheromone From Hymenochirus Sp. Using Analytical Chemistry, Vincent Wing-Kun Leung

University of the Pacific Theses and Dissertations

Male Hymenochirus sp. frogs are known to release pheromone that attracts females of the same species. Four methods for collecting secretions containing pheromone in Hymenochirus sp. were tested: norepinephrine injection, gonadotropin-releasing hormone injection, homogenization of gland tissue, and electrostimulation of the skin over the breeding gland area. The samples collected were analyzed using high-performance liquid chromatography (HPLC) and mass spectrometry. The HPLC chromatograph for the male norepinephrine sample contained a peak at 6.4 min that was not in the female norepinephrine sample HPLC chromatograph. The male norepinephrine sample mass spectrum had a peak of m/z 292.0 not in the female …

Investigating The Effect Of Rutaecarpine On The Benzo[A]Pyrene-Induced Dna Damage In Vitro, You Li

University of the Pacific Theses and Dissertations

Benzo[a]pyrene (BaP), is one of the most potent mutagens and carcinogens known. It requires metabolic activation through cytochrome P450 (CYP)1A1 to yield the ultimate carcinogenic metabolite, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE). BPDE can bind to DNA and form predominantly covalent (+) trans adducts at the N2 position of guanine causing DNA damage. Rutaecarpine (RTC) is an herbal medicine that has been used to treat several diseases such as headache, hypertension, gastrointestinal disorders, amenorrhea, and anti-inflammation. It has also been reported as a potent inducer of CYP enzymes, including CYP1A1, and CYP1A2. The mechanisms underlying up-regulation of CYP1A1 by RTC is dependent on aryl …

Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade

University of the Pacific Theses and Dissertations

Increasing anthropogenic disturbance in marine ecosystems such as fishing, oil-drilling, and noise pollution can have detrimental effects on the reproduction and survival of apex predators such as marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoid (GCs) hormones, which alter expression of target genes encoding metabolic enzymes and other mediators of stress. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. GCs measurements are used to identify wild animals experiencing stress. However, these measurements may not be sensitive enough to distinguish between an …

Discovery Of Small Molecules Blocking Oncogenic K-Ras Activity, Sarah E. Kovar

Browse all Theses and Dissertations

Ras proteins were the first human oncogenes discovered. Although Ras has been found to be the most frequently mutated oncogene, there are currently no anti-Ras-specific drugs available in the clinic. Ras is responsible for initiating cellular pathways that include proliferation, survival, and apoptosis. There are three ubiquitously expressed Ras isoforms in mammalian cells: H-, N-, and K-Ras. Interaction with the plasma membrane is required for Ras biological activity. When Ras interaction with the plasma membrane is blocked, Ras activity is inhibited. Two compounds (from Dr. Ketcha, WSU Chemistry Department) were tested and shown to dissociate K-Ras, but not H-Ras from …

The Selective Survival Of Escherichia Coli In Freshwater Beach Sand, Natalie Ann Rumball

Theses and Dissertations

The quantification of Escherichia coli or E. coli is the most common method used to detect recent fecal pollution in recreational water, as this species is known for its high abundance in fecal matter and assumed host-associated nature. However, it has been determined that some strains are capable of long-term survival and potential propagation in non-host environments, such as the beach sand. These long-term environmental survivors are host-independent and are not associated with the same health risks as those E. coli from recent fecal pollution. However, they have been shown to impact how water quality is perceived as they are …

Characterization Of A Phosphonate-Specific Cytidylyltransferase, Kissa Batul

Theses and Dissertations (Comprehensive)

Antibiotic resistance is a major global health concern that requires new therapeutic approaches. Furthermore, a lack of narrow spectrum antibiotics on the market produces unintended consequences with respect to changes in our microbial make up. Phosphonates are reduced versions of phosphates that possess a C-P bond which is more resistant to enzymatic and chemical degradation. The role of phosphonate containing macromolecules (e.g. cell surface polysaccharides) remains enigmatic, however their presence suggests that they may confer an advantage. The biosynthesis of phosphonate-containing macromolecules is unknown, but a pathway is proposed involving aLicC type cytidylyltransferase-catalyzed conjugation to a phosphonate followed by a …

Ex Vivo Dna Cloning, Adam B. Fisher

Theses and Dissertations

Genetic engineering of microbes has developed rapidly along with our ability to synthesize DNA de novo. Yet, even with decreasing DNA synthesis costs there remains a need for inexpensive, rapid and reliable methods for assembling synthetic DNA into larger constructs or combinatorial libraries. While technological advances have resulted in powerful techniques for in vitro and in vivo assembly of DNA, each suffers inherent disadvantages. Here, an ex vivo DNA cloning suite using crude cellular lysates derived from E. coli is demonstrated to amplify and assemble DNA containing small sequence homologies. Further, the advantages of an ex vivo approach are …

Biochemistry Of 1, 2-Dehydro-N-Acetyldopamine Derivatives, Adal T. Abebe

Graduate Doctoral Dissertations

Dehydrodopa/dopamine derivatives form an important group of biomolecules participating in sclerotization of all arthropod cuticles, gluing and cementing mussels and related organisms to solid surfaces, and defense reactions of countless marine and invertebrate organisms. Yet very little information is available on the biochemistry of these highly reactive and unstable molecules. To understand their physiological role, I conducted a thorough biochemical study on three representative compounds that cover the entire plethora of dehydrodopa/dopamine derivatives. Employing diode array UV-visible spectroscopy, HPLC, liquid chromatography-mass spectrometry, and electrospray ionization tandem mass spectrometry, I investigated the oxidation chemistry of 1,2-dehydro-N-acetyldopamine (dehydro NADA), 1,2-dehydro-N-acetyldopa and 1,2-dehydro-N-acetyldopa …

Elucidating The Role Of Dopamine In The Avoidance Response Of Caenorhabditis Elegans Utilizing Microfluidics, Patricia Frances Turturro

Theses Digitization Project

This study looks at dopamine modulation of ASH neurons, which are part of the avoidance circuit of C. elegans, and their response to water soluble stimuli. Because nematodes such as Caenorhabditis elegans utilize dopamine at the molecular and cellular level in much the same way as mammals, they offer researchers a unique opportunity to study the mechanisms of dopamine signaling.

Cell Type Difference In Influenza A Viral Mrna Nuclear Export, Sean William Larsen

Theses Digitization Project

The focus of this thesis research was to clarify the role of host Nxf1 in influenza viral mRNA nuclear export. This study aims to define the nuclear mRNA export pathways of influenza viral mRNA. If viral mRNAs are discovered to utilize neither known mRNA nuclear export pathway this would indicate the mRNA exports via undefined mRNA nuclear export pathway. This might be an atypical pathway not utilized by many host mRNAs and thus might reveal novel antiviral target. 293T (Human embryonic kidney cells) and A549 (Human lung epithelial) cells were purchased from ATCC American Tissue Culture Collection.

Cell Modeling, Matthew L. Campbell

Theses and Dissertations

The Air Force is currently developing new products that incorporate a variety of chemicals which may come in contact with product users. To define which chemicals are dangerous to the user, toxicity studies have been performed. However, analysis of toxicity ultimately requires models of the exposed cellular systems. This thesis provides an introduction of how to model and analyze small and large cellular systems. Understanding the underlying behavior of small models and their relation to large systems will lead to a better understanding of how the Air Force should construct intracellular models to assist in future toxicology studies. Developing analysis …

In Vitro Assessment Of The Toxicity Of Cocaine And Its Metabolites In The Human Umbilical Artery, Tessa L. Long

Electronic Theses and Dissertations

An in vitro model was used to assess the effect of cocaine and its metabolites on the umbilical artery. Objectives were to pharmacologically confirm the presence of adrenergic innervation using tyramine, evaluate the ability of cocaine, benzoylecgonine, norcocaine and cocaethylene to potentiate vasoconstriction by serotonin and norepinephrine, examine the ability of ketanserin to block the enhanced vasoconstriction produced by cocaine, and determine displacement of 3 H-ketanserin by serotonin, norepinephrine, tyramine and mianserin. The vasoconstrictive effect of tyramine (100 μM) was enhanced in the presence of cocaine by 257%. Vasoconstrictive effects of serotonin and norepinephrine were significantly enhanced by cocaine by …

The Influence Of A Human Repetitive Dna On Genome Stability, Eugenia L. Posey

Electronic Theses and Dissertations

A uniquely human interspersed repetitive DNA sequence family, the L2Hs, are highly polymorphic in human genomes. Several features of interspersed repeated DNA may contribute to the instability observed. Certain motifs (direct repeats, palindromes, and inverted repeats) comprising L2Hs elements may adopt unusual secondary structures such as cruciforms or hairpins. These motifs have been associated with features of genome instability in recombination, insertions and deletions. The L2Hs elements also are AT-rich (76%) compared to the bulk of human DNA (52%). That their dynamic nature (i.e. polymorphisms) may arise from recombination, insertions and deletions has led to the hypothesis that the L2Hs …

Endogenous Alkylglycerol Functions As A Mediator Of Protein Kinase C Activity And Cell Proliferation, Fritz G. Buchanan

Electronic Theses and Dissertations

To explore the possibility that 1-O-alkyl-sn-glycerol (alkylglycerol) may serve a regulatory role in the control of cell proliferation or PKC activity, we examined the ability of alkylglycerol to influence PKC activity and subcellular distribution as well as the ability of alkylglycerol to effect cell proliferation. MDCK cells grown to confluence show a loss of PKC activity associated with the membrane, as reported in fibroblasts. Preconfluent cultures of MDCK cells have a high level of PKC activity associated with the membrane. However, treatment of preconfluent cultures with alkylglycerol causes a reduction of PKC activity. A similar inhibition was observed with alkylglycerol …

Moraxella (Branhamella) Catarrhalis: A Molecular Epidemiology Study, Lyndell R. Gill

Electronic Theses and Dissertations

Moraxella (Branhamella) catarrhalis is the third-most-frequently isolated microorganism associated with acute exacerbations of chronic bronchitis in patients during their stay at the Mountain Home VA Medical Center (MHVAMC). In order to develop a practical, epidemiologically-meaningful typing method for M. (B.) catarrhalis, we tested two methods based on analysis of chromosomal DNA for typeability, reproducibility, and ability to differentiate between unrelated strains (discriminatory power, D). M. (B.) catarrhalis isolants from MHVAMC from 7/1/87-6/30/88 were grown overnight in broth and embedded in agarose. DNA was isolated by standard methods. The DNA was subjected to: (1) restriction endonuclease digestion (with either Bgl II …

A Molecular Basis For Erythromycin Sensitivity And Resistance In Escherichia Coli, Harold S. Chittum

Electronic Theses and Dissertations

The effect of erythromycin on the 50S ribosomal subunit during cell growth has been extensively investigated. Sucrose density gradient analysis of ribosomes formed in the presence and absence of the drug revealed a 50S specific assembly defect is partially responsible for erythromycin's inhibitory effects on wild type cells. Examination of two erythromycin-resistant mutants of E. coli (N281 and N282) revealed that mutant N281 (L22 mutant) but not N282 (L4 mutant) was assembly defective in the presence of the drug, although only at much higher drug concentrations (300 ug/ml vs. 75 ug/ml for wild type cells). The altered genes from each …

Unusual Structure Of A Human Middle Repetitive Dna, Duminda D. Ratnasinghe

Electronic Theses and Dissertations

The L2Hs sequences are a polymorphic, interspersed, middle repetitive DNA family unique to human genomes. Genomic fingerprinting indicates that these DNAs vary from one individual to another and between tissues of the same individual. Sequence analysis reveals that they are AT-rich (76%) and contain many unusual sequence arrangements (palindromes, inverted and direct repeats). These sequence properties confer on the L2Hs elements the potential to fold into non-B-form structures, a characteristic of recombination hot spots. To test this hypothesis carbodiimide, osmium tetroxide and S$\sb1$ nuclease were used as single-strand specific probes to study a recombinant plasmid, pN6.4.39, containing a single L2Hs …

Characterization Of Two Temperature-Sensitive Mutants Of Escherichia Coli Exhibiting An Altered L22 Ribosomal Protein, Bonnie A. Burnette-Vick

Electronic Theses and Dissertations

Analysis of E. coli strains SK1047 and SK1048 have shown them to be temperature-sensitive, protein-synthesis deficient. An alteration in ribosomal protein L22 was detected in both strains using two dimensional gel electrophoresis. Protein L22 was purified from both strains by reversed phase high performance liquid chromatography and from two dimensional electrophoretic gels. Purified ribosomal protein L22 was labeled by reductive methylation and used in 23S RNA binding assays with and without ribosomal protein L4. At the permissive temperature, protein L22 from SK1047 bound less efficiently than the control while protein L22 from SK1048 bound as efficiently as the control. At …