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2001

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Articles 1 - 30 of 35

Full-Text Articles in Molecular Biology

Cold-Temperature Adaptation Of Muscle Creatine Kinase From An Antartic Teleost (Chaenocephalus Aceratus), Paul Winnard Jr. Dec 2001

Cold-Temperature Adaptation Of Muscle Creatine Kinase From An Antartic Teleost (Chaenocephalus Aceratus), Paul Winnard Jr.

Electronic Theses and Dissertations

The white muscle of Chuenocephulus aceratus, an Antarctic teleost of the Channicthyidae family, has a compromised glycoiytic capacity and this fish cannot depend on glycolysis for rapid ATP generation For C. aceratus, creatine kinase (CK) and phosphocreatine (PCr) reserves comprise the metabolic pathway that may supplement and overcome this deficiency in energy transduction. Two conditions, low glycolytic capacity and evolution in a chronically cold habitat (-1.86°C), give us reason to believe that C. aceratus muscle CK (MMCK) has been subjected to strong selective pressure. Thus, the hypothesis of this thesis is that MMCK fiom C. aceratus white muscle ...


Detection Of Insulin Receptor, Epidermal Growth Factor Receptor, And Interleukin-6 On Individual Mouse Embryos By Immuno-Polymerase Chain Reaction, Kun Xu Dec 2001

Detection Of Insulin Receptor, Epidermal Growth Factor Receptor, And Interleukin-6 On Individual Mouse Embryos By Immuno-Polymerase Chain Reaction, Kun Xu

Electronic Theses and Dissertations

Three series of experiments were conducted to: 1) optimize the conditions for the production of pUC19 plasmid and of biotinylated pUC19 fragments; 2) optimize the conditions for the production of protein A-streptavidin chimera (chimeric protein); and 3) detect soluble antigens [bovine serum albumin (BSA) and interleukin-6 (IL-6)] and membrane-bound antigens [insulin receptor and epidermal growth factor receptor (EGFr)] of mouse embryos by immuno-polymerase chain reaction (I-PCR). The first experimental series, which included bacterial culture, chimeric protein purification, and chimeric protein functional experiments, was performed to investigate the effects of IPTG (isopropyl-β-D-thiogalactopyranoside) induction time and temperature, bacterial culture medium, and protein ...


Conformational Changes In Pediocin Ach Upon Vesicle Binding And Approximation Of The Membrane-Bound Structure In Detergent Micelles, Rachel M. Watson, Robert W. Woody, Randolph V. Lewis, D. Scott Bohle, Amy H. Andreotti, Bibek Ray, Kurt W. Miller Oct 2001

Conformational Changes In Pediocin Ach Upon Vesicle Binding And Approximation Of The Membrane-Bound Structure In Detergent Micelles, Rachel M. Watson, Robert W. Woody, Randolph V. Lewis, D. Scott Bohle, Amy H. Andreotti, Bibek Ray, Kurt W. Miller

Biochemistry, Biophysics and Molecular Biology Publications

Pediocin AcH is a 44-residue antimicrobial peptide with bactericidal potency against Gram-positive bacteria such as Listeria. It belongs to a family of bacteriocins that, when membrane-associated, is predicted to contain β-sheet and α-helical regions. All bacteriocins in this family have a conserved N-terminal disulfide bond. An additional C-terminal disulfide bond in pediocin AcH is thought to confer enhanced potency and broader specificity range against sensitive bacteria. The C-terminal disulfide bond may also affect the conformation of the C-terminus. The secondary structures of pediocin AcH in aqueous solution and vesicles from susceptible cells, as well as the ability of trifluoroethanol (TFE ...


Nf-Kappab Signaling Pathways In Mammalian And Insect Innate Immunity, Neal S. Silverman, Tom Maniatis Sep 2001

Nf-Kappab Signaling Pathways In Mammalian And Insect Innate Immunity, Neal S. Silverman, Tom Maniatis

Infectious Diseases and Immunology Publications and Presentations

In this review, we discuss recent advances in understanding the signaling pathways in mammalian and Drosophila innate immunity, with emphasis on the mechanisms by which NF-kappaB/Rel family proteins are activated.


Photodynamic Therapy Of Murine Fibrosarcoma With Topical And Systemic Administration Of Hypericin, I Cavarga, P Brezani, Maria Cekanova, P Solar, P Fedorocko, P Miskovsky Aug 2001

Photodynamic Therapy Of Murine Fibrosarcoma With Topical And Systemic Administration Of Hypericin, I Cavarga, P Brezani, Maria Cekanova, P Solar, P Fedorocko, P Miskovsky

Maria Cekanova MS, RNDr, PhD

The in vivo antitumour activity of the natural photosensitizer hypericin was evaluated. C3H/DiSn mice inoculated with fibrosarcoma G5:1:13 cells were intraperitoneally or intratumourally injected with hypericin (5 mg/kg) and 2 hours later the mice were locally irradiated with laser light (488 nm, 150 mW/cm2, 180 J/cm2) when the tumour reached volume of 40-80 mm3 (approximately 17 days after inoculation). Tumours treated with hypericin alone as well as those irradiated with laser light alone have similar growth rates and none of these tumours regressed spontaneously. The mean tumour volume in hypericin-PDT treated groups was significantly ...


Quinic Acid-Mediated Induction Of Hypovirulence And A Hypovirulence-Associated Double-Stranded Rna In Rhizoctonia Solani, Chunyu Liu Aug 2001

Quinic Acid-Mediated Induction Of Hypovirulence And A Hypovirulence-Associated Double-Stranded Rna In Rhizoctonia Solani, Chunyu Liu

Electronic Theses and Dissertations

This study is a part of a project focused on the relationship between dsRNA and hypovirulence in R. solani. Hypovirulence refers to a condition in which a pathogen has a drastically reduced ability to cause disease. Rhizoctonia solani is a soil-borne pathogen causing diseases in numerous plants. Phenyl acetic acid (PAA), a metabolite of phenylalanine, causes Rhizoctonia disease symptoms on potato in the absence of the pathogen itself. The amount of PAA produced by a hypovirulent isolate is 10% of that produced by virulent isolates. A 3.6 kb dsRNA (M2) has been shown to be associated with hypovirulence in ...


Sir3-Dependent Assembly Of Supramolecular Chromatin Structures In Vitro, Philippe T. Georgel, Madeleine A. Palacios Debeer, Gregory Pietz, Catherine A. Fox, Jeffrey C. Hansen Jul 2001

Sir3-Dependent Assembly Of Supramolecular Chromatin Structures In Vitro, Philippe T. Georgel, Madeleine A. Palacios Debeer, Gregory Pietz, Catherine A. Fox, Jeffrey C. Hansen

Biological Sciences Faculty Research

Baculovirus-expressed recombinant Sir3p (rSir3p) has been purified to near homogeneity, and its binding to naked DNA, mononucleosomes, and nucleosomal arrays has been characterized in vitro. At stoichiometric levels rSir3p interacts with intact nucleosomal arrays, mononucleosomes, and naked DNA, as evidenced by formation of supershifted species on native agarose gels. Proteolytic removal of the core histone tail domains inhibits but does not completely abolish rSir3p binding to nucleosomal arrays. The linker DNA in the supershifted complexes remains freely accessible to restriction endonuclease digestion, suggesting that both the tail domains and nucleosomal DNA contribute to rSir3p–chromatin interactions. Together these data indicate ...


Immunoprecipitation Of A Nadph Oxidase System Gtpase, Rac2, From The Human Neutrophil And The Gtp-Dependent Activity Of Rac2 In A Phosphorylation-Dependent Cell-Free System, Rachel Brennan Apr 2001

Immunoprecipitation Of A Nadph Oxidase System Gtpase, Rac2, From The Human Neutrophil And The Gtp-Dependent Activity Of Rac2 In A Phosphorylation-Dependent Cell-Free System, Rachel Brennan

Life and Environmental Sciences Undergraduate Theses

The neutrophil is an integral part of the body’s line of defense against infectious microbial agents. Its microbicidal activity is carried out by NADPH oxidase, an enzyme that uses electron transfer to create superoxide (O2"), which is then transformed into various toxins that are responsible for the demise of the foreign microorganism. The oxidase system is composed of membrane and cytosolic components. One of the cytosolic components is a low molecular-weight member of the Rho family of GTPases, Rac2. A genetic link has recently been established between Rac2 and Chronic Granulomatomous Disease (CGD), a disease in which the body ...


The Involvement Of C-Terminal Amino Acids In The Formation Of Prion Protein Dimers, Rebecca Phillip Apr 2001

The Involvement Of C-Terminal Amino Acids In The Formation Of Prion Protein Dimers, Rebecca Phillip

Life and Environmental Sciences Undergraduate Theses

Accumulations o f abnormal prion protein are thought to be the cause o f the transmissible spongiform encephalopathies, which are degenerative brain diseases. Throughout the disease process it is hypothesized that there is some sort of binding that occurs among the proteins. This research project involved the search for a strong, most likely covalent, linkage in a dimer of prion proteins. The focus was on the amino acid sequence o f the prion protein from 220 to 232. The lysine residue in this sequence was of particular concern due to its involvement in covalent linkages in other proteins (Priola et ...


The N-Terminal Segment Of Recombinant Porcine Fructose-1,6-Bisphosphatase Participates In The Allosteric Regulation Of Catalysis, Scott W. Nelson, Feruz T. Kurbanov, Richard B. Honzatko, Herbert J. Fromm Mar 2001

The N-Terminal Segment Of Recombinant Porcine Fructose-1,6-Bisphosphatase Participates In The Allosteric Regulation Of Catalysis, Scott W. Nelson, Feruz T. Kurbanov, Richard B. Honzatko, Herbert J. Fromm

Biochemistry, Biophysics and Molecular Biology Publications

Residues 1–10 of porcine fructose-1,6-bisphosphatase (FBPase) are poorly ordered or are in different conformations, sensitive to the state of ligation of the enzyme. Deletion of the first 10 residues of FBPase reducesk cat by 30-fold and Mg2+ affinity by 20-fold and eliminates cooperativity in Mg2+ activation. Although a fluorescent analogue of AMP binds with high affinity to the truncated enzyme, AMP itself potently inhibits only 50% of the enzyme activity. Additional inhibition occurs only when the concentration of AMP exceeds 10 mM. Deletion of the first seven residues reduces k cat and Mg2+ affinity ...


Nuclear Export Of 60s Ribosomal Subunits Depends On Xpo1p And Requires A Nuclear Export Sequence-Containing Factor, Nmd3p, That Associates With The Large Subunit Protein Rpl10p, Olivier Gadal, Daniela Strau, Jacques Kessl, Bernard Trumpower Feb 2001

Nuclear Export Of 60s Ribosomal Subunits Depends On Xpo1p And Requires A Nuclear Export Sequence-Containing Factor, Nmd3p, That Associates With The Large Subunit Protein Rpl10p, Olivier Gadal, Daniela Strau, Jacques Kessl, Bernard Trumpower

Open Dartmouth: Faculty Open Access Articles

Nuclear export of ribosomes requires a subset of nucleoporins and the Ran system, but specific transport factors have not been identified. Using a large subunit reporter (Rpl25p-eGFP), we have isolated several temperature-sensitive ribosomal export (rix) mutants. One of these corresponds to the ribosomal protein Rpl10p, which interacts directly with Nmd3p, a conserved and essential protein associated with 60S subunits. We find that thermosensitive nmd3 mutants are impaired in large subunit export. Strikingly, Nmd3p shuttles between the nucleus and cytoplasm and is exported by the nuclear export receptor Xpo1p. Moreover, we show that export of 60S subunits is Xpo1p dependent. We ...


An Early Transition State For Folding Of The P4-P6 Rna Domain., Scott K. Silverman, Thomas R. Cech Feb 2001

An Early Transition State For Folding Of The P4-P6 Rna Domain., Scott K. Silverman, Thomas R. Cech

Chemistry & Biochemistry Faculty Contributions (1986-2018)

Tertiary folding of the 160-nt P4-P6 domain of the Tetrahymena group I intron RNA involves burying of substantial surface area, providing a model for the folding of other large RNA domains involved in catalysis. Stopped-flow fluorescence was used to monitor the Mg2+-induced tertiary folding of pyrene-labeled P4-P6. At 35 degrees C with [Mg2+] approximately 10 mM, P4-P6 folds on the tens of milliseconds timescale with k(obs) = 15-31 s(-1). From these values, an activation free energy deltaG(double dagger) of approximately 8-16 kcal/mol is calculated, where the large range for deltaG(double dagger) arises from uncertainty in ...


Protein Targeting And Translocation, Barry D. Bruce, D.A. Phoenix Jan 2001

Protein Targeting And Translocation, Barry D. Bruce, D.A. Phoenix

Faculty Publications and Other Works -- Biochemistry, Cellular and Molecular Biology

No abstract provided.


Phylogeographic Analysis Of The Threatened And Endangered Superconglutinate-Producing Mussels Of The Genus Lampsilis (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard, Paul D. Hartfield Jan 2001

Phylogeographic Analysis Of The Threatened And Endangered Superconglutinate-Producing Mussels Of The Genus Lampsilis (Bivalvia: Unionidae), Kevin J. Roe, Charles Lydeard, Paul D. Hartfield

Kevin J. Roe

Several species of freshwater unionid mussels in the genus Lampsilis exhibit a remarkable reproductive strategy. Female mussels of these species enclose their larvae in a minnow-like lure, called a ‘superconglutinate’, to attract piscivorous fishes. When a fish attempts to ingest the superconglutinate the lure ruptures and the larvae are released to parasitize the fish. Of the four species of mussel which exhibit this strategy and are endemic to the Gulf Coast drainages of the southeastern United States, three are protected under the Endangered Species Act, and one is recognized as imperilled. Phylogenetic analysis of nucleotide sequences of the mitochondrial 16S ...


Voltage Gating Of A Model Membrane Spanning Channel, Eric Miller Jan 2001

Voltage Gating Of A Model Membrane Spanning Channel, Eric Miller

Inquiry: The University of Arkansas Undergraduate Research Journal

Channels in cell membranes are important for intercellular communication and especially for the function of the nervous system in higher vertebrates. These channels consist of proteins made from the 20 common amino acids. Channel proteins are embedded into the lipid bilayer membranes of living cells and function by allowing the specific passage of a positively charged material such as sodium or potassium ions across the membrane in response to an external signal. The external signaloeither a chemical signal or a voltageoregulates the opening and closing of channels. In an attempt to understand the voltage-dependent opening of channels (igatingi), we are ...


Adrenal Expression Of Cyp17 And Hsd3b1 Mrna In Peromyscus Maniculatus Bairdii, Brian Thomas Lovitt Jan 2001

Adrenal Expression Of Cyp17 And Hsd3b1 Mrna In Peromyscus Maniculatus Bairdii, Brian Thomas Lovitt

Dissertations, Theses, and Masters Projects

No abstract provided.


Response Of Plant Growth And Development To Different Light Conditions In Three Model Plant Systems , Hanhong Bae Jan 2001

Response Of Plant Growth And Development To Different Light Conditions In Three Model Plant Systems , Hanhong Bae

Retrospective Theses and Dissertations

Shade avoidance response to the reduced ratio of red:far-red (R:FR) light was studied in a white aspen Populus alba clone 'Bolleana' using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The response to low R:FR The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were ...


Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu Jan 2001

Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu

Retrospective Theses and Dissertations

Photosystem I, one of the two light driven reaction centers of oxygenic photosynthesis, functions as the light-driven plastocyanin-ferredoxin oxidoreductase in the thylakoid membranes of cyanobacteria and chloroplasts. It is a pigment protein complex with 11--14 proteins and several types of organic (e.g. chlorophyll a) and inorganic energy and electron transfer cofactors (e.g. Fe-S cluster). The objectives of this dissertation are: (i) to demonstrate that the spectroscopic and kinetic properties of photosystem I cofactors are determined by the protein environments, (ii) to determine whether the electron transfer in photosystem I is unidirectional or bidirectional, (iii) to identify which aromatic ...


Molecular Characterization Of Cultured Perkinsus Marinus Isolates, Gwynne D. Brown Jan 2001

Molecular Characterization Of Cultured Perkinsus Marinus Isolates, Gwynne D. Brown

Dissertations, Theses, and Masters Projects

Perkinsus marinus is the causative agent of the oyster disease Dermo in the eastern oyster, Crassostrea virginica. In vitro propagation of the parasite has led to the establishment of multiple isolates by several investigators. Little work, however, has been done to characterize different isolates. In this study multiple isolates were examined for genetic and biochemical diversity. at two loci, the ITS region and the ATAN region, there was as much intra-isolate genetic variation among DNA sequences of some isolates as there was inter-isolate variation. Variation was also observed at a third loci, a subtilisin-like serine protease gene. This is the ...


The 1dx5 High Molecular Weight Subunit Gene From Wheat In Transgenic Maize , Varaporn Sangtong Jan 2001

The 1dx5 High Molecular Weight Subunit Gene From Wheat In Transgenic Maize , Varaporn Sangtong

Retrospective Theses and Dissertations

We have developed a method for detecting a transgene and its protein product in maize endosperm that allows the kernel to be germinated after analysis. Our method involves first sampling the endosperm with a hand-held rotary grinder. This tissue is then serially extracted for phenotypic analysis by SDS-PAGE with visualization by total protein staining or immuno-blot detection and genotypic analysis by PCR reactions to detect the transgene. This method is useful for screening transgenic kernels in breeding experiments. We have produced transgenic maize plants containing a wheat Glu-1Dx5 gene encoding the high molecular weight glutenin subunit 1Dx5. Analysis by SDS-PAGE ...


Genetic Analysis Of Reproductive Traits In Soybean [Glycine Max (L) Merr] , I. Made Tasma Jan 2001

Genetic Analysis Of Reproductive Traits In Soybean [Glycine Max (L) Merr] , I. Made Tasma

Retrospective Theses and Dissertations

The objectives of this study were to: (1) estimate the number of genes controlling photoperiod insensitivity in soybean; (2) map quantitative trait loci controlling flowering time, maturity, and photoperiod insensitivity in soybean; (3) map homologous and cloned flowering time gene sequences in soybean; (4) correlate these sequences with maturity (E) loci by means of near isogenic lines (NILs). Three populations, two F 6:7 recombinant inbred lines of 101 and 100 progeny and an F2:4 G. max x G. soja population (60 progeny), were used. Forty-one NILs were also included. At least three genes were proposed to control photoperiod ...


Functional Analysis Of Hoxa5: Analysis Of Structural, Behavioral, And Molecular Effects Of Hoxa5 Overexpression In Transgenic Line Hoxa5sv2 , Karin Elizabeth Krieger Jan 2001

Functional Analysis Of Hoxa5: Analysis Of Structural, Behavioral, And Molecular Effects Of Hoxa5 Overexpression In Transgenic Line Hoxa5sv2 , Karin Elizabeth Krieger

Retrospective Theses and Dissertations

The purpose of this research was to provide new information on the role of a murine homeobox gene, Hoxa5, in the development of the central and peripheral nervous systems. Although Hoxa5 is expressed in the brachial spinal cord and enteric neuroblasts during development, no neural phenotype has yet been observed in the Hoxa5 knockout mutant. In the work reported here, functional HOXA5 protein was overexpressed in the developing nervous system in transgenic mice in order to gain insight into the mechanisms by which this gene exerts its effects during development. Evaluation of the phenotypes of F0 transgenics and transgenic animals ...


Response To S1 Recurrent Selection And Estimation Of Genetic Parameters In Effective Population Sizes Of The Bs11 Maize Population , Kebede Mulatu Ponta Jan 2001

Response To S1 Recurrent Selection And Estimation Of Genetic Parameters In Effective Population Sizes Of The Bs11 Maize Population , Kebede Mulatu Ponta

Retrospective Theses and Dissertations

Recurrent selection is a cyclical breeding technique that has become popular in comprehensive maize improvement strategies. The magnitude of response in recurrent selection depends upon the modes of gene action and their frequencies in effective population sizes. We studied four effective population sizes with the objectives: (1) to estimate response to selection and inbreeding effects, (2) to partition the response to selection into that due to additive and dominance genetic components, and (3) to examine changes in the correlated traits. Four effective population sizes 5, 10, 20, and 30 were developed by S1-progeny selection in the BS11 maize population using ...


Phospholipase C Of Clostridium Hemolyticum: Gene Characterization And Proof Of Its Role As A Protective Immunogen In Guinea Pigs , Paul Joseph Hauer Jan 2001

Phospholipase C Of Clostridium Hemolyticum: Gene Characterization And Proof Of Its Role As A Protective Immunogen In Guinea Pigs , Paul Joseph Hauer

Retrospective Theses and Dissertations

The phospholipase C (PLPC) gene from Clostridium hemolyticum was cloned using the polymerase chain reaction. An open reading frame which encodes a 399-amino acid protein, containing a 27-amino acid signal sequence, was identified. The molecular weight of the active protein was 42,869 daltons. A 16-amino acid N-terminal sequence determined by Edman degradation exactly matched the putative amino acid sequence of the gene product. Comparison of the nucleotide and amino acid sequences with Genebank databases demonstrated that the beta toxin of C. hemolyticum exhibits high homology with other bacterial PLPCs. The N-terminal portion of the beta toxin contains the zinc-binding ...


Studying The Replication Mechanism Of The Yeast Retrotransposon Ty5 By Molecular And Computational Approaches, Xiang Gao Jan 2001

Studying The Replication Mechanism Of The Yeast Retrotransposon Ty5 By Molecular And Computational Approaches, Xiang Gao

Retrospective Theses and Dissertations

The yeast retrotransposon Ty5 is a Ty1/copia element. It is in the Hemivirus genus of the Pseudoviridae family. The ability to genetically manipulate retrotransposons and the yeast host cell was taken advantage of to explore replication mechanisms unique to Ty5 and common to most retrotransposons. Because of the abundance and diversity of retroelement sequences, along with the fact that many retroelement enzymes have evolved unique functional specificities, computational approaches were also developed to study functional divergence in replication. By screening a randomly mutagenized Ty5 library, two mutations (Y68C, D252N) causing higher transposition frequencies were identified. Both mutations increased Ty5 ...


Coordination Of Cell Morphology And Nuclear Division By The Bud Neck Control Ring In Saccharomyces Cerevisiae , Courtney Lynn Thomas Jan 2001

Coordination Of Cell Morphology And Nuclear Division By The Bud Neck Control Ring In Saccharomyces Cerevisiae , Courtney Lynn Thomas

Retrospective Theses and Dissertations

Coordination of daughter cell growth and nuclear division are readily observed but not well understood in the yeast Saccharomyces cerevisiae . A screen was performed to identify mutants which lost this coordination such that they exhibited an elongated cell morphology (improper cell growth), but continued to divide. The results of this screen and suppressor analysis suggests the bud neck ring is a control structure which determines cell morphology as well as nuclear division as an upstream regulator of Cdc28p-cyclin complexes.;The effects of mutations in specific components of the bud neck ring on the assembly of other components into the structure ...


Drosophila Jil-1 Kinase Mediates Histone H3 Ser10 Phosphorylation, Maintains Higher Order Chromatin Structure, And Is Implicated In Dosage Compensation , Yanming Wang Jan 2001

Drosophila Jil-1 Kinase Mediates Histone H3 Ser10 Phosphorylation, Maintains Higher Order Chromatin Structure, And Is Implicated In Dosage Compensation , Yanming Wang

Retrospective Theses and Dissertations

The Drosophila JIL-1 tandem Ser/Thr kinase is associated with chromosomes/chromatin throughout the cell cycle in early embryos and localized to hundreds of sites on the open interband regions on third instar larvae polytene chromosomes. Interestingly, the level of JIL-1 is upregulated on the male X chromosome, which is hypertranscribed for dosage compensation. The distribution of JIL-1 overlaps with that of MSL (male specific lethal) proteins and JIL-1 is associated with the MSL complex.;To further study the function of JIL-1 in vivo, a series of JIL-1 mutants from hypomorphs to null were generated. Analyzing the phenotypes of JIL-1 ...


Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen Jan 2001

Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen

Retrospective Theses and Dissertations

Barley yellow dwarf virus RNA contains a translation element (3 'TE) that confers efficient cap-independent initiation at the 5 proximal AUG. Direct end-labeling of RNAs verified the absence of a 5 ' modification on virion RNA. Thus BYDV differs from related viruses by having neither a genome-linked protein nor a 5 ' cap. To function in the 3' UTR, the 3 'TE must recruit ribosomes and associated translation factors, and communicate with the 5' end of the mRNA where translation initiates. The communication function is mediated by direct base pairing between the 3'TE and the 5' UTR. We propose that protein ...


Human Hexokinase: Multiple Mechanisms Of G6p Inhibition , Xiaofeng Liu Jan 2001

Human Hexokinase: Multiple Mechanisms Of G6p Inhibition , Xiaofeng Liu

Retrospective Theses and Dissertations

Human hexokinase I catalyzes the first step in glycolysis, playing a key role in the energy metabolism of brain tissue. The chapters included in this thesis focus on structure-function relationships of hexokinase I. Glucose 6-phosphate (G6P), the reaction product, binds to hexokinase I with apparent negative cooperativity and inhibits catalysis (Chapter II). Both N- and C-terminal binding sites for G6P are functional, yet only one G6P molecule binds to hexokinase I.;A series of site-directed mutations were constructed in the base- and ribose-binding pocket of ATP in C-terminal half of hexokinase I G6P inhibition completely (Chapter III). The same mutations ...


Molecular And Genetic Characterization Of Rf2, A Mitochondrial Aldehyde Dehydrogenase Gene Required For Male Fertility In Maize (Zea Mays L) , Xiangqin Cui Jan 2001

Molecular And Genetic Characterization Of Rf2, A Mitochondrial Aldehyde Dehydrogenase Gene Required For Male Fertility In Maize (Zea Mays L) , Xiangqin Cui

Retrospective Theses and Dissertations

T-cytoplasm induced male sterility (cms-T) is a maternally inherited inability to produce viable pollen in maize. The causal factor, the URF13 protein, is encoded by the mitochondrial genome and accumulates in the mitochondrial inner membrane. Fertility restoration of cms-T is mediated by the complementary action of two nuclear genes, rf1 and rf2. The rf2 gene was cloned via transposon tagging. Sequence analysis revealed that it has high sequence similarity to mammalian mitochondrial aldehyde dehydrogenases (mtALDHs). Sequence, mRNA, and protein analyses of the spontaneous mutant allele rf2-R213 demonstrated that the ALDH activity is necessary for rf2's function as a cms-T ...