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Molecular Biology

1999

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Articles 1 - 30 of 42

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor Ambros Dec 1999

Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor Ambros

Open Dartmouth: Faculty Open Access Scholarship

During postembryonic development of Caenorhabditis elegans, the heterochronic gene lin-14 controls the timing of developmental events in diverse cell types. Three alternativelin-14 transcripts are predicted to encode isoforms of a novel nuclear protein that differ in their amino-terminal domains. In this paper, we report that the alternative amino-terminal domains of LIN-14 are dispensable and that a carboxy-terminal region within exons 9 to 13 is necessary and sufficient for in vivo LIN-14 function. A transgene capable of expressing only one of the three alternativelin-14 gene products rescues a lin-14 null mutation and is developmentally regulated by lin-4. This shows ...


A Defect In Interleukin 12-Induced Activation And Interferon Gamma Secretion Of Peripheral Natural Killer T Cells In Nonobese Diabetic Mice Suggests New Pathogenic Mechanisms For Insulin-Dependent Diabetes Mellitus., Marika Falcone, Brian Yeung, Lee Tucker, Enrique Rodriguez, Nora Sarvetnick Oct 1999

A Defect In Interleukin 12-Induced Activation And Interferon Gamma Secretion Of Peripheral Natural Killer T Cells In Nonobese Diabetic Mice Suggests New Pathogenic Mechanisms For Insulin-Dependent Diabetes Mellitus., Marika Falcone, Brian Yeung, Lee Tucker, Enrique Rodriguez, Nora Sarvetnick

Journal Articles: Regenerative Medicine

The function of natural killer T (NKT) cells in the immune system has yet to be determined. There is some evidence that their defect is associated with autoimmunity, but it is still unclear how they play a role in regulating the pathogenesis of T cell-mediated autoimmune diseases. It was originally proposed that NKT cells could control autoimmunity by shifting the cytokine profile of autoimmune T cells toward a protective T helper 2 cell (Th2) type. However, it is now clear that the major function of NKT cells in the immune system is not related to their interleukin (IL)-4 secretion ...


Exploring Ground-State Heterogeneity Of Hypericin And Hypocrellin A And B:  Dynamic And 2d Roesy Nmr Study, Alexandre V. Smirnov, D. Bruce Fulton, Amy H. Andreotti, Jacob W. Petrich Aug 1999

Exploring Ground-State Heterogeneity Of Hypericin And Hypocrellin A And B:  Dynamic And 2d Roesy Nmr Study, Alexandre V. Smirnov, D. Bruce Fulton, Amy H. Andreotti, Jacob W. Petrich

Chemistry Publications

A NMR study was conducted on the antiviral and antitumor agents hypericin and hypocrellin A and B, whose activity is light induced. Elucidation of the conformational/tautomeric properties of these polycyclic quinones is important for interpreting their photophysical behavior in the excited state. Evidence for interconversion between ground-state tautomers or other conformational isomers was sought in temperature-dependent 1H NMR and 2D-ROESY studies. For hypericin and hypocrellin B, only one ground-state species is observed. For hypocrellin A, however, three species are significantly populated in the ground state due to the high flexibility of its 7-membered ring. In the latter case dynamic ...


Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen Jul 1999

Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen

Theses and Dissertations in Biomedical Sciences

Using JEG-3 cells as an in vitro model, I investigated the mechanisms behind the tissue-specific expression and steroid hormone regulation of the hGnRH gene in the human placenta. The hGnRH upstream promoter was found to be functionally active in JEG-3 cells. The DNA sequence responsible for functioning of the upstream promoter in JEG-3 cells is narrowed to a region between –1048 bp and –730 bp. This DNA fragment contains four elements, which can bind with nuclear extract from JEG-3 cells (but not from GT1-7 cells).

Estradiol (E2) represses the hGnRH upstream promoter activity in JEG-3 cells. This inhibition is receptor-mediated ...


Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof. Jun 1999

Phd Thesis (Doctorat De Spécialité): Université De Ouagadougou, 1999. Dr. Mamoudou H. Dicko. Purification Et Propriétés Physico-Chimiques Des Enzymes De Curculigo Pilosa, Gladiolus Klattianus Et Boscia Senegalensis Catalysant L'Hydrolyse Des Polysaccharides (Amidon Et Béta-Glucanes), Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The objective of this study was the research of novel and inexpensive sources of polysaccharides degrading enzymes such as amylases and glucanases from local plants in order to justify their biotechnological applications. The isolation of two l3-amylases and an endo-1,3-ß-D-glucanase was reached using common protein purification methods such as buffer extraction, ammonium sulfate fractionation, ionexchange and gel filtration chromatographies. The methods used were simple and easily reproducible, suggesting the possibilfty of large-scale production. ln the crude extract of Curculigo pilosa tuber, only ß-amylase was detected as starch degrading enzyme and its activity was approximately 282 Uig of fresh material ...


Activated Mono-, Di-, And Polysaccharides Reaction Products Thereof, Their Preparation And Uses, John F. Robyt, Rupendra Mukerjea May 1999

Activated Mono-, Di-, And Polysaccharides Reaction Products Thereof, Their Preparation And Uses, John F. Robyt, Rupendra Mukerjea

Iowa State University Patents

Reaction at the interface of an organic solution containing an acidic reactant and an aqueous alkaline solution containing nonreducing carbohydrates such as sucrose, sugar alcohols, cyclodextrins, and polysaccharides imparts a specificity to the reaction for one or more of the primary alcohol groups of the carbohydrate reactant. The resulting activated, nonreducing carbohydrate intermediate can then be converted to a series of substantially pure, low molecular weight reaction products, including a sucrose trimer and dianhydrosucrose, and to a series of substantially pure, higher molecular weight reaction products, including 6-O-sucro cyclodextrins and poly-6-O-sucro amylose.


Secondary Metabolites From Montana Isolates Of Penicillium, Jennifer Hill Apr 1999

Secondary Metabolites From Montana Isolates Of Penicillium, Jennifer Hill

Chemistry and Physics Undergraduate Theses

Extracellular and intracellular secondary metabolites were extracted from w different cultures of Penicillium, isolated mostly from rust galls on lodgepole and ponderosa pine in Montana. Extracts containing the fungal metabolites were applied to silica-gel thin layer chromatography strips by blotting agar plugs from mycelial cultures. Chromatograms were developed with appropriate solvents in chromatography chambers. The chromatograms were then viewed under normal light and ultraviolet light at wavelengths of 254 nm and 366 nm. Standard literature was used to identify the metabolites. Results show that new metabolites as well as some previously reported metabolites are produced by these Montana Penicillium isolates.


Studies Of Mosaicism For Chromosomal Aneuploidy In Fetal Loss Using Fluorescence In Situ Hybridization On Several Tissue Types, Aaron Knox Apr 1999

Studies Of Mosaicism For Chromosomal Aneuploidy In Fetal Loss Using Fluorescence In Situ Hybridization On Several Tissue Types, Aaron Knox

Life and Environmental Sciences Undergraduate Theses

The main objective ofthis study was to determine the presence and level of mosaicism for chromosomal aneuploidy in several cases of fetal demise that had previous indications of chromosome aberrations. The presence of aneuploidy was determined using fluorescence in situ hybridization (FISH) probes. Techniques that were utilized in attempts to prepare several tissue types for FISH are described. The analyses made with FISH provided useful data on the chromosomal makeup oftwo of the cases studied. In one case FISH results showed that the product of conception (POC) did not contain the trisomy 18 that is present at low levels in ...


Production Of Copper-Complexing Ligands In Response To Elevated Concentrations Of Copper In Marine Synechococcus Spp., Arunsri Chatkaeomorakot Brown Apr 1999

Production Of Copper-Complexing Ligands In Response To Elevated Concentrations Of Copper In Marine Synechococcus Spp., Arunsri Chatkaeomorakot Brown

Theses and Dissertations in Biomedical Sciences

Synechococcus spp. (marine cyanobacteria) are extremely sensitive to copper toxicity and can produce high-affinity ligands of unknown structure which form complexes with free cupric ion. These ligands may contribute to the biological control of the levels of free cupric ions in surface seawater. Synechococcus spp. are known to produce metallothioneins (MT) in response to cadmium and zinc stress. In the present study the hypothesis that marine Synechococcus produce MT in response to copper was tested. Three marine Synechococcus spp. i.e., PCC 7001, PCC 73109, and PCC 7003, were exposed to different concentrations of CUSO 4 for various time periods ...


Linear And Cyclic Sucrose Reaction Products, Their Preparation And Their Use, John F. Robyt, Rupendra Makerjea Mar 1999

Linear And Cyclic Sucrose Reaction Products, Their Preparation And Their Use, John F. Robyt, Rupendra Makerjea

Iowa State University Patents

Sucrose ester and ether products, useful as food or beverage bulking agents, reduced calorie sweeteners, fat replacement agents, stabilizing agents, thickening agents and emulsifying agents; adhesives; biodegradable plastics and films; sizing agents for paper and textiles; ethical pharmaceuticals and new fibers are prepared by using a two-phase reaction system in which sucrose is dissolved in an alkaline, aqueous solution and an acidic reagent such as a bifunctional acid dichloride or epoxide is added to the sucrose in a water-immiscible organic solvent. Several types of products are produced: water-insoluble sucrose ester (ether) copolymers; water-soluble sucrose ester (ether) copolymers; sucrose ester (ether ...


A Copper Cofactor For The Ethylene Receptor Etr1 From Arabidopsis, Brad Binder, Fernando Rodríguez, Jeffrey Esch, Anne Hall, G. Schaller, Anthony Bleecker Jan 1999

A Copper Cofactor For The Ethylene Receptor Etr1 From Arabidopsis, Brad Binder, Fernando Rodríguez, Jeffrey Esch, Anne Hall, G. Schaller, Anthony Bleecker

Brad M. Binder

The ETR1 receptor from Arabidopsis binds the gaseous hormone ethylene. A copper ion associated with the ethylene-binding domain is required for high-affinity ethylene-binding activity. A missense mutation in the domain that renders the plant insensitive to ethylene eliminates both ethylene binding and the interaction of copper with the receptor. A sequence from the genome of the cyanobacterium Synechocystis sp. strain 6803 that shows homology to the ethylene-binding domain of ETR1 encodes a functional ethylene-binding protein. On the basis of sequence conservation between the Arabidopsis and the cyanobacterial ethylene-binding domains and on in vitro mutagenesis of ETR1, a structural model for ...


Genome-Wide Bioinformatic And Molecular Analysis Of Introns In Saccharomyces Cerevisiae, Marc Spingola, Leslie Grate, David Haussler, Manuel Ares Jan 1999

Genome-Wide Bioinformatic And Molecular Analysis Of Introns In Saccharomyces Cerevisiae, Marc Spingola, Leslie Grate, David Haussler, Manuel Ares

Marc Spingola

Introns have typically been discovered in an ad hoc fashion: introns are found as a gene is characterized for other reasons. As complete eukaryotic genome sequences become available, better methods for predicting RNA processing signals in raw sequence will be necessary in order to discover genes and predict their expression. Here we present a catalog of 228 yeast introns, arrived at through a combination of bioinformatic and molecular analysis. Introns annotated in the Saccharomyces Genome Database (SGD) were evaluated, questionable introns were removed after failing a test for splicing in vivo, and known introns absent from the SGD annotation were ...


Development Of A Novel Assay For The Detection Of Viral Stability In Lyophilized Vaccines, Jeffrey Thomas Blue Jan 1999

Development Of A Novel Assay For The Detection Of Viral Stability In Lyophilized Vaccines, Jeffrey Thomas Blue

Theses and Dissertations

No abstract provided.


Transcriptional Regulation Of The Bmp2 Gene: Retinoic Acid Induction In F9 Embryonal Carcinoma Cells And Saccharomyces Cerevisiae, Loree C. Heller, Yong Li, Kevin L. Abrams, Melissa B. Rogers Jan 1999

Transcriptional Regulation Of The Bmp2 Gene: Retinoic Acid Induction In F9 Embryonal Carcinoma Cells And Saccharomyces Cerevisiae, Loree C. Heller, Yong Li, Kevin L. Abrams, Melissa B. Rogers

Bioelectrics Publications

Bmp2, a highly conserved member of the transforming growth factor-beta gene family, is crucial for normal development. Retinoic acid, combined with cAMP analogs, sharply induces the Bmp2 mRNA during the differentiation of F9 embryonal carcinoma cells into parietal endoderm. Retinoic acid (RA) also induces the Bmp2 gene in chick limb buds. Since normal Bmp2 expression may require an endogenous retinoid signal and aberrant Bmp2 expression may cause some aspects of RA-induced teratogenesis, we studied the mechanism underlying the induction of Bmp2. Measurements of the Bmp2 mRNA half-life and nuclear run-on assays indicated that ...


Environmental Stress In Hard Coral: Evaluating Lipid As An Indicator Of Sublethal Stress On Short Time Scales, David Harold Niebuhr Jan 1999

Environmental Stress In Hard Coral: Evaluating Lipid As An Indicator Of Sublethal Stress On Short Time Scales, David Harold Niebuhr

Dissertations, Theses, and Masters Projects

Lipid quality was evaluated in Montastrea spp. under sediment- and heat-stressed conditions to evaluate lipid ratio as an indicator of sub-lethal stress on short time scales. The ratio of storage lipid (wax ester + triacylglyceride) to structural lipid (sterol esters + phospholipid) decreased significantly (0.25 to 0.14, p < 0.01) after experimental sedimentation. FAME analysis of colonies exposed to experimental sedimentation showed a reduction of the algal, 18:3(n-6) and 18:4(n-3), polyunsaturated fatty acid (PUFA) in the polar lipid fraction. This loss of PUFA suggests a loss of algal membrane in sediment-stressed colonies. Lipid quality was similarly measured in M. faveolata over a 10-day period. Mean (n = 20) ratio of storage to structural lipid in M. faveolata dropped from 2.43 to a level of 0.98 immediately following a natural sedimentation event before recovering to levels of 1.4 and 2.9 on post-storm days 2 and 4, respectively. Colonies of M. annularis subject to heat-stress (35??C) exhibited no significant change in storage lipid ratio, while levels of Free Fatty Acids increased significantly from 0.012 (n = 22) to 0.156 mg lipid/g dry tissue (n = 22)(p < 0.05). FAME analysis of tissue lipids extracted from the heat-stressed colonies showed changes in the polar fraction, with significant decreases in the 18:3(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3) (p < 0.05) PUFA and subsequent significant increases in the saturated fatty acids, 16:0 and 18:0 (p < 0.05). These changes in lipid quantity and quality indicate possible oxidation and preferential digestion of zooxanthellar membranes. Stress experiments were repeated in M. annularis using VacutainerRTM blood collection tubes to collect micro-tissue samples without destroying skeleton of the sample colonies. A significant decrease in storage: structural lipid ratio after sedimentation was also detected using the micro-tissue technique. This study indicates that the relative abundance of lipid subclass components can indicate sub-lethal environmental stress, on short time scales, in M. annularis and M. faveolata. Furthermore, micro-tissue collection techniques permit repeated monitoring coral colonies to assess the manifestation of stress from first detection of impact at the cellular level to changes in community to changes in community structure detectable over longer time scales.


The Effects Of Neutrophil-Mediated Damage In Acute Mannheimia (Pasteurella) Haemolytica Pneumonia , Zaher Ahmad Khalil Radi Jan 1999

The Effects Of Neutrophil-Mediated Damage In Acute Mannheimia (Pasteurella) Haemolytica Pneumonia , Zaher Ahmad Khalil Radi

Retrospective Theses and Dissertations

ICAM-1 expression in cattle with Bovine Leukocyte Adhesion Deficiency (BLAD) vs. cattle without BLAD in Mannheimia haemolytica (MH) pneumonia at 2 or 4 hours PI was assessed using in situ hybridization. There was a significant increase in ICAM-1 in bronchiolar and alveolar epithelium and endothelium of arteries and veins in both BLAD and non-BLAD MH-inoculated cattle compared to controls. Highest intensity of ICAM-1 was present in bronchioles while bronchi had the lowest. Most alveolar macrophages and neutrophils in infected lungs expressed ICAM-1. ICAM-1 expression was generally increased in infected BLAD cattle at 2 hours PI compared to non-BLAD but not ...


Molecular And Genetic Analysis Of Jil-1, A Chromatin Associated Protein Kinase Implicated In Transcriptional Regulation In Drosophila , Ye Jin Jan 1999

Molecular And Genetic Analysis Of Jil-1, A Chromatin Associated Protein Kinase Implicated In Transcriptional Regulation In Drosophila , Ye Jin

Retrospective Theses and Dissertations

Chromatin remodeling is an essential step for many chromatin-related fundamental cellular processes, such as gene replication, transcription, recombination and gene silencing. Two classes of protein complexes contribute to chromatin remodeling: protein complexes with ATPase activity and protein complexes capable of enzymatic modifications of chromosomal proteins, especially histones. Compared to well-studied histone acetylation which has been directly linked to gene transcription, the role of histone phosphorylation in chromatin remodeling for gene transcription is still poorly understood although there is some correlation between histone phosphorylation and gene transcription;A novel nuclear tandem protein kinase JIL-1 was cloned and identified in Kristen Johansen ...


32p-Postlabeling Analysis Of Aromatic Dna Adducts In Hemopoietic Tissues And Blood Of The Mummichog Fundulus Heteroclitus, Wendy L. Rose Jan 1999

32p-Postlabeling Analysis Of Aromatic Dna Adducts In Hemopoietic Tissues And Blood Of The Mummichog Fundulus Heteroclitus, Wendy L. Rose

Dissertations, Theses, and Masters Projects

No abstract provided.


Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev Jan 1999

Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev

Retrospective Theses and Dissertations

Barley yellow dwarf virus (BYDV) is an important pathogen of cereal crops. It has a single-stranded positive sense genomic RNA (gRNA), 5.7 kilobases. During infection of a plant cell, BYDV generates a nested set of three subgenomic mRNAs (sgRNAs) for expression of its 3'-proximal genes. The goal of this study was to map and characterize cis-acting RNA signals involved in transcription and replication of BYDV RNA. Three sgRNA promoters and the 3' origin of replication were characterized. The sgRNA1 promoter was mapped to a 98 nt region that contains two stem-loop structures. A combination of primary and secondary ...


The Glycogen Phosphorylase/ Phosphorylase Kinase Interaction: Effects Of Mutations In The Amino-Terminal Region Of Glycogen Phosphorylase , Alyssa Christine Biorn Jan 1999

The Glycogen Phosphorylase/ Phosphorylase Kinase Interaction: Effects Of Mutations In The Amino-Terminal Region Of Glycogen Phosphorylase , Alyssa Christine Biorn

Retrospective Theses and Dissertations

Glycogen phosphorylase is an important enzyme for carbohydrate metabolism in muscle. It uses inorganic phosphate to remove glucose from glycogen, producing glucose-1-phosphate, which can be used for the production of ATP. Inactive glycogen phosphorylase (phosphorylase h) is activated either by the allosteric binding of 5'-AMP, or by phosphorylation by phosphorylase kinase (PhK). Phosphorylation produces phosphorylase a, which is active in the absence of AMP. PhK is the only kinase that can phosphorylate phosphorylase b, which in turn is the only substrate for PhK. This dissertation research has attempted to determine the reasons for this specificity and how these two ...


Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov Jan 1999

Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov

Retrospective Theses and Dissertations

The dissertation focuses on the ultrafast primary photoprocesses of the title anti-viral and anti-cancer agents, whose activity depends on light which is also accompanied by photoacidification in vesicles and living cells;By complementing the techniques of time-resolved absorption spectroscopy with those of fluorescence upconversion and applying them to hypericin, hypocrellin A and B, and their methylated analogs that are unable to execute proton transfer, it was demonstrated that intramolecular excited-state hydrogen atom transfer is a dominant primary nonradiative process;For hypocrellin A in viscous solvents such as octanol and ethylene glycol, an absorption transient of ∼10-ps duration, similar to the ...


Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan Jan 1999

Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan

Retrospective Theses and Dissertations

Members of the lentivirus subfamily of retroviruses are characterized as causing slow, chronic disease. Atypical of other lentiviruses, such as human immunodeficiency virus type 1, equine infectious anemia virus (EIAV) may produce a rapid, variable disease course in horses. Infected horses may undergo an, acute episode of disease involving viremia, fever, and thrombocytopenia. Following this acute period, horses may resolve to an inapparent infection or suffer a chronic period of additional cycles of viremia, fever, and thrombocytopenia. Horses which survive clinical episodes usually become inapparent carriers of the virus for life. Numerous virus and host factors contribute to the phenotypic ...


Novel G-Dna Binding Proteins From The Ciliate Tetrahymena Thermophila: Purification, Characterization, Cloning And Functional Analyses , Quan Lu Jan 1999

Novel G-Dna Binding Proteins From The Ciliate Tetrahymena Thermophila: Purification, Characterization, Cloning And Functional Analyses , Quan Lu

Retrospective Theses and Dissertations

G-DNA is a family of novel four-stranded DNA structures characterized by motifs called G-quartets. Evidence is growing to suggest that G-DNA exists and plays biological roles in vivo. In order to further elucidate the functions of G-DNA, we have studied proteins that specifically bind to the DNA structure;Two G-DNA binding activities, TGPI and TGP3, were purified from the ciliate Tetrahymena thermophila. Based on the peptide sequences obtained from direct internal peptide sequencing, the cDNAs coding for the genes were cloned. Deduced protein sequences showed that TGP1 and TGP3 are novel proteins but share significant homology with each other. Furthermore ...


Assessment Of Plant Introductions For Increasing The Genetic Variability Of Soybean Populations , James Mark Narvel Jan 1999

Assessment Of Plant Introductions For Increasing The Genetic Variability Of Soybean Populations , James Mark Narvel

Retrospective Theses and Dissertations

Plant introductions (PIs) may increase the genetic variability of soybean populations and lead to greater genetic gains from selection. Five soybean populations containing different percentages of PI parentage were developed at Iowa State University to evaluate the use of PIs for increasing genetic variability for seed yield in a recurrent selection program. The objective of this study was to evaluate the performance and genetic variability of the Cycle 4 (C4) populations of AP 10 (100 % PI), AP 11 (75 % PI), AP12 (50 % PI), AP13 (25 % PI), and AP14 (0 % PI) for agronomic traits and seed composition. Multiplexing technology for simple ...


Fatty Acid Modification Of Cells In Culture By Overexpression Of Exogenous Desaturases , Travis Jay Knight Jan 1999

Fatty Acid Modification Of Cells In Culture By Overexpression Of Exogenous Desaturases , Travis Jay Knight

Retrospective Theses and Dissertations

COS-1 cells were transfected transiently with expression vectors encoding stearoyl-acyl-carrier-protein desaturase (SACPD) from castor bean, stearoyl-CoA desaturase (SCD) from mice, and a control vector containing SACPD cDNA in reverse orientation. The hypothesis was that both exogenous desaturases would be active in COS-1 cells, thereby increasing the proportion of monounsaturated fatty acids produced by the cells. Messenger RNA and anti-myc immunoreactive proteins were detected at 12 and 24 hours post-transfection respectively and increased through 48 hours post-transfection. When acetate was used as the fatty acid precursor in cultures for a 24-hour period starting 24 hours post-transfection, the ratio of monounsaturated to ...


Dynamic Changes In The Localization Of Synapse Associated Proteins During Development And Differentiation Of The Mammalian Retina , Mary Heather West Greenlee Jan 1999

Dynamic Changes In The Localization Of Synapse Associated Proteins During Development And Differentiation Of The Mammalian Retina , Mary Heather West Greenlee

Retrospective Theses and Dissertations

We have examined the developmental distribution and differential localization of presynaptic terminal associated proteins in the mammalian retina. We have used antibodies specific for synaptic vesicle associated proteins Synaptotagmin, Rab 3A, Synaptophysin and Synaptobrevin, and presynaptic terminal membrane associated proteins SNAP-25 and Syntaxin, to characterize their spatio-temporal distribution during retinal differentiation and in the mature retina;The vertebrate retina has a laminar organization consisting of three cellular layers separated by two synaptic layers, the inner piexiform layer and the outer plexiform layer. In general, immunoreactivity for presynaptic terminal associated proteins was first observed in cellular layers, and as differentiation progressed ...


Molecular Characterization Of Myb-Homologous Transcriptional Factors Of The Flavonoid Pathway In Zea Mays , Peifen Zhang Jan 1999

Molecular Characterization Of Myb-Homologous Transcriptional Factors Of The Flavonoid Pathway In Zea Mays , Peifen Zhang

Retrospective Theses and Dissertations

Structural genes encoding enzymes that catalyze each step of flavonoid synthesis are temporally and spatially regulated. It has been shown that specific anthocyanin pigmentation patterns in maize are achieved by the tissue-specific expression of regulatory genes. Moreover, this tissue-specific regulation is a consequence of the generation of different alleles or duplicated copies of regulatory genes during evolution;In contrast, the myb-homologous P1 gene was the only known regulatory gene required for phlobaphene biosynthesis. The isolation and characterization of the P2 gene, reported here, provides direct molecular evidence that the P region contains duplicated genes. Furthermore, the duplicated P1 (herein, P1-rr ...


Genome Reorganization And Non-Linear Transposition In Maize , Jianbo Zhang Jan 1999

Genome Reorganization And Non-Linear Transposition In Maize , Jianbo Zhang

Retrospective Theses and Dissertations

Transposable elements have long been considered as potential agents of large-scale genome reorganization by virtue of their ability to induce chromosomal rearrangements such as deletions, duplications, inversions, and reciprocal translocations. Previous researchers have shown that particular configurations of transposon termini can induce chromosome rearrangements at high frequencies. By analyzing two derivatives of an unstable allele of the maize P1 (pericarp color) gene carrying both a full-length Ac (Activator) transposable element and a Ac terminal fragment termed fAc (fractured Ac) that were recovered from a classical maize ear twinned sector, it were found that the twinned alleles are a large inverted ...


Genetic Mobility And Instability Of Retroviral Vector In Vector Producer Cells For Gene Therapy, Won-Bin Young Jan 1999

Genetic Mobility And Instability Of Retroviral Vector In Vector Producer Cells For Gene Therapy, Won-Bin Young

Retrospective Theses and Dissertations

A primary biosafety issue of retroviral vector-mediated gene therapy is the genetic instability of retroviral vectors. Reverse transcription of vector RNA genome is initiated by viral reverse transcriptase (RT) in a virion particle after infection of a target cell. During reverse transcription, abnormal template switches between vector and occasionally co-packaged helper virus in a virion particle can therefore enable helper virus to regain replication elements from the vector and revert to replication-competent retrovirus (RCR). This research was undertaken to study the origins of RT enzyme activities and test the hypothesis that RT enzyme activities are contributed by both exogenous RT ...


Oxidizing Side Of The Photosystem I , Jun Sun Jan 1999

Oxidizing Side Of The Photosystem I , Jun Sun

Retrospective Theses and Dissertations

Photosynthesis converts solar energy into the biological sources of energy for the life on our planet. Photosystem I (PSI) is one of the two reaction centers of oxygenic photosynthesis. PSI is a multiheteromeric membrane-protein complex that catalyzes light-driven electron transfer from plastocyanin or cytochrome c6 to ferredoxin. The PsaA and PsaB subunits form the heterodimeric core that harbors the primary electron donor P700. On the oxidizing side of the PSI complex, plastocyanin or cytochrome c6 donates electrons to the P700 reaction center. The objective of this dissertation is to identify elements of molecular recognition on the oxidizing side of PSI ...