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 …

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 …

Melatonin And Its Metabolites Protect Human Melanocytes Against Uvb-Induced Damage: Involvement Of Nrf2-Mediated Pathways, Zorica Janjetovic, Stuart G. Jarrett, Elizabeth F. Lee, Cory Duprey, Russel J. Reiter, Andrzej T. Slominski

Toxicology and Cancer Biology Faculty Publications

Ultraviolet light (UV) is an inducer of reactive oxygen species (ROS) as well as 6-4-photoproducts and cyclobutane pyrimidine dimers (CPD) in the skin, which further cause damage to the skin cells. Irradiation of cultured human melanocytes with UVB stimulated ROS production, which was reduced in cells treated with melatonin or its metabolites: 6-hydroxymelatonin (6-OHM), N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), N-acetylserotonin (NAS), and 5-methoxytryptamine (5-MT). Melatonin and its derivatives also stimulated the expression of NRF2 (nuclear factor erythroid 2 [NF-E2]-related factor 2) and its target enzymes and proteins that play an important role in cell protection from different damaging factors including UVB. Silencing …

Reverse Gyrase Is Not Necessary For Survival Of Hyperthermophilic Archaeon Pyrococcus Furiosus, Farshid Taghizadeh, Michael S. Bartlett

Student Research Symposium

Reverse gyrase is the only known topoisomerase enzyme with positive supercoiling activity on covalently-closed DNA. This positive supercoiling is required to prevent DNA from denaturation at high temperatures. The gene that codes for this protein is present in all hyperthermophiles and absent from all mesophilic and thermophilic genomes, suggesting that this enzyme is the only hyperthermophile-specific protein. To investigate if this protein is vital for the cells, we knocked out its gene from the genome of living organism Pyrococcus furiosus. Pyrococcus furiosus is a hyperthermophilic archaeon that grows between 70°C to 103°C with an optimum growth temperature of 100°C. …

Identification Of Proteins Potentially Involved In The Formation Of Lafora Bodies, A Hallmark Of Lafora Disease, Elham Schokraie, Oliver Kötting, Matthew S. Gentry

Molecular and Cellular Biochemistry Presentations

Lafora Disease (LD) is a fatal teenage-onset progressive myoclonus epilepsy. It is characterized by the formation of Lafora bodies (LBs), deposits of abnormally branched, insoluble, hyperphosphorylated glycogen-like polymers that are generally believed to trigger the development of the clinical symptoms of LD. 58% and 35% of the LD cases are caused by mutations in EPM2A (laforin) and EPM2B (malin), respectively. However, little is known about their function in LB formation. Two different mechanisms have been proposed to explain the accumulation of insoluble LBs: first, excessive glycogen phosphorylation and, second, an imbalance between glycogen synthesizing enzymes. The present study aims at …

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 …

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 …

Mouse Mast Cell Proteases: Induction, Molecular Cloning, And Characterization, Wei Chu

Electronic Theses and Dissertations

Tryptase, a mast cell-specific serine protease with trypsin-like specificity, has been identified in a mouse mast cell line (ABFTL-6) based on it's enzymatic activity, inhibition properties, and cross-reactivity to a human mast cell tryptase antibody. The effects of fibroblast-conditioned medium and sodium butyrate on ABFTL-6 mast cell differentiation and tryptase expression have been examined. ABFTL-6 mouse mast cells undergo phenotypic changes upon culturing in media supplemented with fibroblast-conditioned media at 50% or 1 mM sodium butyrate. The induced cells increased in size, had larger and more metachromatic cytoplasmic granules, and increased their total cellular protein about four-fold. Tryptase activity increased …