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Molecular Biology

1994

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Articles 1 - 30 of 45

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

Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar, Shaojie Wang, James P. Allen, Carl E. Bauer Oct 1994

Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar, Shaojie Wang, James P. Allen, Carl E. Bauer

David Bollivar

Site-directed mutational analysis of the Rhodobacter capsulatus photosynthesis gene cluster was undertaken in order to identify and characterize genetic loci involved in bacteriochlorophyll a biosynthesis. A mutant in orf304 was shown to accumulate the tetrapyrrole intermediate "bacteriochlorophyllide a" which is a tetrapyrrole that has a bacteriochlorophyll a ring structure without the presence of an esterifying alcohol. A mutant in orf391 is shown to synthesize acteriochlorophyll a that is esterified with geranylgeraniol rather than the normal phytol. This latter result provides the first genetic confirmation that esterification of bacteriochlorophyllide a initially involves the addition of a geranylgeraniol group followed by sequential ...


Effect Of Charged Residue Substitutions On The Membrane-Interactive Properties Of Signal Sequences Of The Escherichia Coli Lamb Protein., Jeffrey Jones, Lila Gierasch Oct 1994

Effect Of Charged Residue Substitutions On The Membrane-Interactive Properties Of Signal Sequences Of The Escherichia Coli Lamb Protein., Jeffrey Jones, Lila Gierasch

Lila Gierasch

Although the central role of the signal sequence in protein export is well established, the molecular details underlying signal sequence in vivo function remain unclear. As part of our continuing effort to relate signal sequence phenotypes to specific biophysical properties, we have carried out an extensive characterization of the secondary structure and lipid interactions for a family of peptides corresponding to the wild-type E. coli LamB signal sequence, and mutants that harbor charged residue point mutations in the hydrophobic core region. We used membrane-resident fluorescence quenching according to the parallax method to determine the relative depth of insertion of tryptophan-labeled ...


The Pha-4 Gene Is Required To Generate The Pharyngeal Primordium Of Caenorhabditis-Elegans, Susan E. Mango, Eric J. Lambie, Judith Kimble Oct 1994

The Pha-4 Gene Is Required To Generate The Pharyngeal Primordium Of Caenorhabditis-Elegans, Susan E. Mango, Eric J. Lambie, Judith Kimble

Open Dartmouth: Faculty Open Access Scholarship

In the 4-cell Caenorhabditis elegans embryo, two blastomeres are destined to generate pharyngeal cells, each by a distinct developmental strategy: one pathway is inductive, while the other is autonomous. Here, we identify the pha-4 locus. In animals lacking pha-4 activity, an early step in pharyngeal organogenesis is blocked: no pharyngeal primordium is formed and differentiated pharyngeal cells are absent. Most other tissues are generated normally in pha-4 mutants, including cells related to pharyngeal cells by cell lineage and position. Thus, pha-4 activity is required to form the pharyngeal primordium. We propose that pha-4 marks a convergence of the inductive and ...


Lag-2 May Encode A Signaling Ligand For The Glp-1 And Lin-12 Receptors Of C-Elegans, Samuel T. Henderson, Dali Gao, Eric J. Lambie, Judith Kimble Oct 1994

Lag-2 May Encode A Signaling Ligand For The Glp-1 And Lin-12 Receptors Of C-Elegans, Samuel T. Henderson, Dali Gao, Eric J. Lambie, Judith Kimble

Open Dartmouth: Faculty Open Access Scholarship

The C. elegans lag-2 gene is required for several cell-cell interactions that rely on the receptors GLP-1 and LIN-12. In this paper, we report that lag-2 encodes a putative membrane protein with sequence similarity to Drosophila Delta, a proposed ligand for the Notch receptor. Furthermore, we show that the lag-2 promoter drives expression of a reporter protein in the signaling distal tip cell (DTC) of the DTC/germline interaction. By in situ hybridization, we have found that endogenous lag-2 mRNA is present in the DTC but not the germ line. One fusion protein, called LAG-2::beta-gal(intra), rescues a lag-2 ...


Effect Of Charged Residue Substitutions On The Thermodynamics Of Signal Peptide-Lipid Interactions For The Escherichia Coli Lamb Signal Sequence., Jeffrey D. Jones, Lila Gierasch Sep 1994

Effect Of Charged Residue Substitutions On The Thermodynamics Of Signal Peptide-Lipid Interactions For The Escherichia Coli Lamb Signal Sequence., Jeffrey D. Jones, Lila Gierasch

Lila Gierasch

We have used tryptophan fluorescence spectroscopy to characterize the binding affinities of an Escherichia coli LamB signal peptide family for lipid vesicles. These peptides harbor charged residue substitutions in the hydrophobic core region. Titrations of peptides with vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine and 1-palmitoyl-2-oleoyl-sn-3-phosphoglycerol (65:35 mol%), in conjunction with evaluation of peptide dissociation rates from these vesicles, were used to determine binding parameters quantitatively. We find that under low ionic strength conditions, point mutations introducing negatively charged aspartate residues substantially reduce peptide affinity relative to the wild-type peptide. However, the difference between wild-type and mutant peptide affinities was much lower ...


Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar Sep 1994

Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar

Scholarship

No abstract provided.


Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar, Ze-Yu Jiang, Carl E. Bauer, Samuel I. Beale Aug 1994

Heterologous Expression Of The Bchm Gene Product From Rhodobacter Capsulatus And Demonstration That It Encodes S-Adenosyl-L-Methionine: Mg-Protoporhyrin Ix Methyltransferase, David Bollivar, Ze-Yu Jiang, Carl E. Bauer, Samuel I. Beale

David Bollivar

The bacteriochlorophyll biosynthesis gene, bchM, from Rlodobacter capsulatus was previously believed to code for a polypeptide involved in formation of the cyclopentone ring of protochlorophyllide from Mg-protoporphyrin IX monomethyl ester. In this study, R. capsulatus bchM was expressed in Escherichia coli and the gene product was subsequently demonstrated by enzymatic analysis to catalyze methylation of Mg-protoporphyrin IX to form Mg-protoporphyrin IX monomethyl ester. Activity required the substrates Mg-protoporphyrin IX and S-adenosyl-L-methionine. 14C-labeled product was formed in incubations containing 14C-methyl-labeled S-adenosyl-L-methionine. On the basis of these and previous results, we also conclude that the bchH gene, which was previously reported to ...


Structure-Substrate Binding Relationships Of Hiv-1 Reverse Transcriptase, Steve Chien-Wen Huang Jul 1994

Structure-Substrate Binding Relationships Of Hiv-1 Reverse Transcriptase, Steve Chien-Wen Huang

Theses and Dissertations in Biomedical Sciences

Human Immunodeficiency Virus, type 1 (HIV-1), is the causative agent of the Acquired Immunodeficiency Syndrome (AIDS). HIV-1 reverse transcriptase (RT), a heterodimer p66/p51, has been the major target for treatment of AIDS. The significance of the p51 subunit and the RNase H domain of p66 in terms of their influence on the RNA-dependent DNA synthesis was investigated. Clones of the wildtype HIV-1 RT subunits, p66 and p51, and a recombinant C-terminal deletion mutant, p64, [Barr, P. J. (1987) Bio/Technoloav 5, 486-489] were employed to study the structure-substrate binding relationships of HIV-1 RT. The activity assays of RNA-dependent DNA ...


Reorganization Of Lipid Domain Structure In Membranes By A Transmembrane Peptide: An Esr Spin Label Study On The Effect Of The Escherichia Coli Outer Membrane Protein A Signal Peptide On The Fluid Lipid Domain Connectivity In Binary Mixtures Of Dimyristoyl Phosphatidylcholine And Distearoyl Phosphatidylcholine., M. Sankaram, D. Marsh, Lila Gierasch, T. Thompson Jun 1994

Reorganization Of Lipid Domain Structure In Membranes By A Transmembrane Peptide: An Esr Spin Label Study On The Effect Of The Escherichia Coli Outer Membrane Protein A Signal Peptide On The Fluid Lipid Domain Connectivity In Binary Mixtures Of Dimyristoyl Phosphatidylcholine And Distearoyl Phosphatidylcholine., M. Sankaram, D. Marsh, Lila Gierasch, T. Thompson

Lila Gierasch

The effect of a transmembrane peptide on the domain structure of a two-component, two-phase lipid bilayer composed of dimyristoyl phosphatidylcholine (DMPC) and distearoyl phosphatidylcholine (DSPC) was examined by spin label electron spin resonance (ESR) spectroscopy. The peptide, pOmpA, is the hydrophobic, 25-residue signal sequence of the outer membrane protein A from Escherichia coli. Nitroxide derivatives of the phospholipid DSPC, 16-DSPCSL, and of the pOmpA signal peptide, pOmpA-IASL, were used as probes. The first-derivative lineshapes of the ESR spectra were analyzed using a normalized intensity ratio, R, that gives information on the average sizes of the disconnected fluid domains and their ...


Molecular Determinants Of Glut1: Structure And Function: A Dissertation, Ralph J. Zottola Jun 1994

Molecular Determinants Of Glut1: Structure And Function: A Dissertation, Ralph J. Zottola

GSBS Dissertations and Theses

Hebert and Carruthers (1992) showed that the human erythrocyte glucose transporter is an allosteric complex of four GLUT1 proteins whose structure and substrate binding properties are stabilized by reductant-sensitive noncovalent subunit interactions. The GLUT1 tetramer dissociates into dimers upon exposure to reductant but subunits are not associated via disulfide bridges. Each subunit of SDS-denatured tetrameric GLUT1 exposes only two thiols while reduced denatured GLUT1 exposes all six sulfhydryl groups. They hypothesized that glucose transporter oligomeric structure and cooperative catalytic function resulted from noncovalent subunit interactions promoted or stabilized by intramolecular disulfide bridges. These interactions give rise to an antiparallel arrangement ...


The Phosphate Transporter From Pea Mitochondria (Isolation And Characterization In Proteolipid Vesicles), Cecilia A. Mcintosh, David J. Oliver May 1994

The Phosphate Transporter From Pea Mitochondria (Isolation And Characterization In Proteolipid Vesicles), Cecilia A. Mcintosh, David J. Oliver

David J. Oliver

The phosphate transporter from mitochondria will exchange matrix phosphate for cytosolic phosphate and facilitate either phosphate/proton symport or phosphate/hydroxyl ion antiport. The phosphate transported into the matrix by this carrier is either used for ATP synthesis or exchanges back out to the cytosol on the dicarboxylate transporter, permitting entry of malate and succinate into the matrix. The phosphate transporter was solubilized from etiolated pea (Pisum sativum L. cv Alaska) mitochondrial membranes with Triton X-114, purified approximately 500-fold by hydroxylapatite chromatography, and reconstituted into azolectin vesicles that were preloaded with 0.1 or 10 mM phosphate. Phosphate transport was ...


Production Of Interleukin 10 By Islet Cells Accelerates Immune-Mediated Destruction Of Beta Cells In Nonobese Diabetic Mice., Lise Wogensen, Myung-Shik Lee, Nora Sarvetnick Apr 1994

Production Of Interleukin 10 By Islet Cells Accelerates Immune-Mediated Destruction Of Beta Cells In Nonobese Diabetic Mice., Lise Wogensen, Myung-Shik Lee, Nora Sarvetnick

Journal Articles: Regenerative Medicine

The T helper type 2 (Th2) cell product interleukin 10 (IL-10) inhibits the proliferation and function of Th1 lymphocytes and macrophages (M phi). The nonobese diabetic mouse strain (NOD/Shi) develops a M phi and T cell-dependent autoimmune diabetes that closely resembles human insulin-dependent diabetes mellitus (IDDM). The objective of the present study was to explore the consequences of localized production of IL-10 on diabetes development in NOD/Shi mice. Surprisingly, local production of IL-10 accelerated the onset and increased the prevalence of diabetes, since diabetes developed at 5-10 wk of age in 92% of IL-10 positive I-A beta g7 ...


Development Of An Assay To Determine The Amount Of Binding Between Dna And The Carcinogen (+)-Anti-Benzo (A) Pyrene Diol Eopxide, Cher Wright Apr 1994

Development Of An Assay To Determine The Amount Of Binding Between Dna And The Carcinogen (+)-Anti-Benzo (A) Pyrene Diol Eopxide, Cher Wright

Life and Environmental Sciences Undergraduate Theses

A method for determining the number of carcinogenic molecules bound (adducted) to a DNA sequence was studied. Samples of purified plasmid DNA were exposed to increasing concentrations of the carcinogenic chemical benzo(a)pyrene diol epoxide (BPDE). Treated plasmids then served as the template in a Polymerase Chain Reaction (PCR). Desired test regions of the plasmid were selectively amplified. Samples from the PCR were then electrophoresed to study the number of successful copies produced by the PCR and the size and density of the bands. DNA replication levels decreased proportionately as BPDE exposure concentrations increased. The results suggest that the ...


Translational Regulation Of The C-Jun Proto-Oncogene, Anil Sehgal Apr 1994

Translational Regulation Of The C-Jun Proto-Oncogene, Anil Sehgal

Theses and Dissertations in Biomedical Sciences

The v-jun oncogene was originally isolated from the ASV17 virus in 1987. Ever since its isolation, extensive work has been done to understand the role of the v-jun oncogene in cell transformation. The c-Jun protein is a transcription factor which binds to the DNA target TGACTCA. The c-Jun protein binds to DNA in the form of dimers. It can form homodimers with itself and heterodimers with Jun family (JunB and JunD), Fos family (FosB, Fra1 and Fra2), or with CREB family members through the leucine zipper motif. Because the c-jun proto-oncogene plays an important role in cell transformation, extensive work ...


Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D S. Peabody Mar 1994

Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D S. Peabody

Marc Spingola

The coat proteins of RNA phages MS2 and GA are specific RNA-binding proteins which function to encapsidate viral RNA and to translationally repress synthesis of the viral replicase. The two proteins have highly homologous amino acid sequences, yet they show different RNA binding specificities, recognizing RNA stem-loop structures which differ primarily in the nucleotide sequences of their loops. We sought to convert MS2 coat protein to the RNA binding specificity of GA through the introduction of GA-like amino acid substitutions into the MS2 coat protein RNA-binding site. The effects of the mutations were determined by measuring the affinity of the ...


Pancreatic Islet Production Of Murine Interleukin-10 Does Not Inhibit Immune-Mediated Tissue Destruction., Myung-Shik Lee, Lise Wogensen, Judith Shizuru, Michael B.A. Oldstone, Nora Sarvetnick Mar 1994

Pancreatic Islet Production Of Murine Interleukin-10 Does Not Inhibit Immune-Mediated Tissue Destruction., Myung-Shik Lee, Lise Wogensen, Judith Shizuru, Michael B.A. Oldstone, Nora Sarvetnick

Journal Articles: Regenerative Medicine

IL-10 inhibits macrophage-dependent antigen presentation, cytokine production, and generation of allospecific cells in vitro. These findings have lead to the widespread expectation that IL-10 may be a useful immunosuppressive agent to inhibit allograft rejection or autoimmunity in vivo. We used two experimental paradigms to study effects of murine IL-10 on in vivo immune responses. First, fetal pancreata or adult pancreatic islets from transgenic mice expressing IL-10 in pancreatic beta cells (Ins-IL-10 mice) were grafted across the MHC barrier to examine if IL-10 could inhibit allograft rejection. Second, Ins-IL-10 mice were crossed with transgenic mice expressing lymphocytic choriomeningitis virus (LCMV) antigens ...


The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton Jan 1994

The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton

Michael Sinensky

The conversion of mammalian prelamin A to mature lamin A proceeds through the removal of 18 amino acids from the carboxyl terminus. The initial step in this processing is the isoprenylation of a CAAX box cysteine. This proteolytic event is distinctive for prelamin A among the known prenylated mammalian proteins. Since the carboxyl terminus of prelamin A is removed during maturation, it is not obvious that this protein would undergo the two reactions subsequent to prenylation observed in other CAAX box proteins-the endoproteolytic removal of the carboxyl-terminal 3 amino acids and the subsequent methylation of the now carboxyl-terminal cysteine. To ...


Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle Jan 1994

Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle

Michael Sinensky

No abstract provided.


Multisite Microprobes For Electrochemical Recordings In Biological Dynamics, G. Sreenivas, S. S. Ang, R. M. Ranade, A. S. Salian, W. D. Brown Jan 1994

Multisite Microprobes For Electrochemical Recordings In Biological Dynamics, G. Sreenivas, S. S. Ang, R. M. Ranade, A. S. Salian, W. D. Brown

Journal of the Arkansas Academy of Science

For over 30 years, techniques have been developed that allow for the microscale (10-30 /mum) measurement of chemical signals with high temporal resolution (1-200 Hz). Such measurements, called in vivo electrochemical recordings, allow for the direct determination of neurotransmitter molecules and related compounds in biological systems. Multiple recordings, simultaneously performed at different, closely spaced, well defined locations throughout a three-dimensional tissue volume in the brain, are of interest in neuroscience. Developments in microelectronic techniques enable the fabrication of multi-electrode microprobes for recording extracellular action potentials generated by individual neurons simultaneously. A high-yield microfabrication process has been successfully developed for the ...


Molecular Cloning Of Cdnas And Genes Coding For Beta-Methylcrotonyl-Coa Carboxylase Of Tomato, Xun Wang, Eve S. Wurtele, Greg Keller, Angela L. Mckean, Basil J. Nikolau Jan 1994

Molecular Cloning Of Cdnas And Genes Coding For Beta-Methylcrotonyl-Coa Carboxylase Of Tomato, Xun Wang, Eve S. Wurtele, Greg Keller, Angela L. Mckean, Basil J. Nikolau

Botany Publication and Papers

Tomato cDNA and genomic clones were isolated by using as a probe a cDNA clone that had originally been identified by its ability to direct the synthesis of a biotin-containing polypeptide in Escherichia coli. The nucleotide sequences of the newly isolated cDNAs indicate that they are clones of a single mRNA molecule. However, one of the cDNA clones contains an insertion of a sequence which we identified as an unspliced intron. The amino acid sequence deduced from the nucleotide sequence of the cDNAs showed similarity to regions of previously sequenced biotin enzymes, indicating that the isolated cDNAs code for a ...


The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton Jan 1994

The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton

Faculty Publications

The conversion of mammalian prelamin A to mature lamin A proceeds through the removal of 18 amino acids from the carboxyl terminus. The initial step in this processing is the isoprenylation of a CAAX box cysteine. This proteolytic event is distinctive for prelamin A among the known prenylated mammalian proteins. Since the carboxyl terminus of prelamin A is removed during maturation, it is not obvious that this protein would undergo the two reactions subsequent to prenylation observed in other CAAX box proteins-the endoproteolytic removal of the carboxyl-terminal 3 amino acids and the subsequent methylation of the now carboxyl-terminal cysteine. To ...


Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle Jan 1994

Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle

Faculty Publications

No abstract provided.


Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar Jan 1994

Molecular Genetic Analysis Of Terminal Steps In Bacteriochlorophyll A Biosynthesis: Characterization Of A Rhodobacter Capsulatus Strain That Synthesizes Geranylgeranoil-Esterified Bacteriochlorophyll A, David Bollivar

Scholarship

No abstract provided.


Novel Suicide Elements For Gene Disruption In Escherichia Coli, Brian Christopher Nicholson Jan 1994

Novel Suicide Elements For Gene Disruption In Escherichia Coli, Brian Christopher Nicholson

Dissertations, Theses, and Masters Projects

No abstract provided.


Purification, Characterization And Cloning Of A Periplasmic Catalase From B Abortus And The Role It Plays In The Pathogenesis Of Brucella , Zheng Yu Sha Jan 1994

Purification, Characterization And Cloning Of A Periplasmic Catalase From B Abortus And The Role It Plays In The Pathogenesis Of Brucella , Zheng Yu Sha

Retrospective Theses and Dissertations

A periplasmic catalase has been identified and purified from Brucella abortus using a procedure which fractionates periplasmic B. abortus proteins from other cellular components while retaining biological activity. The biochemical characteristics of the purified enzyme were studied and the gene encoding the enzyme cloned and sequenced. SDS polyacrylamide gel electrophoresis of the purified enzyme revealed only a single subunit with a molecular weight of 59,000. Gel filtration indicates the native protein is a tetramer. The native protein has a visible absorption spectrum with maxima at 407, 501, and 628 nm which is typical of mammalian, but not some bacterial ...


Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, Qijing Zhang Jan 1994

Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, Qijing Zhang

Retrospective Theses and Dissertations

A microtiter plate adherence assay for Mycoplasma hyopneumoniae was established by using purified swine tracheal cilia which are the natural targets for the mycoplasma. M. hyopneumoniae bound specifically to solubilized cilia immobilized onto microtiter plates. Dextran sulfate, heparin, chondroitin sulfate, laminin, mucin, and fucoidan significantly inhibited binding of the mycoplasmas to cilia. Heparin, mucin, fucoidan, and chondroitin sulfate interacted with the adhesins on the surface of mycoplasmas, whereas laminin blocked the receptors in cilia. Treatment of cilia with neuraminidase appeared to promote adherence of the mycoplasmas; whereas, treatment of cilia with sodium metaperiodate decreased the binding. In the second study ...


Expression Of Chlamydomonas Reinhardtii Periplasmic Carbonic Anhydrase In Escherichia Coli And Transgenic Tobacco Plants , Cyril Sebastian Roberts Jan 1994

Expression Of Chlamydomonas Reinhardtii Periplasmic Carbonic Anhydrase In Escherichia Coli And Transgenic Tobacco Plants , Cyril Sebastian Roberts

Retrospective Theses and Dissertations

Carbonic anhydrase (CA) catalyzes the reversible hydration of CO2. The periplasmic CA gene CAH1 of Chlamydomonas reinhardtii codes for a highly processed secreted glycoprotein. The primary translation product of the CAH1 gene is targeted to the algae's ER, where it is proteolytically processed to yield two different subunits, glycosylated, assembled into an active heterotetramer, and secreted. Expression of CAH1 in Escherichia coli and tobacco plants were effected in this study. For bacterial expression, two constructs, one with and another without, the algal target leader sequence were used. Similarly, after replacing the algal's target leader sequence with that from ...


Characterization And Immunogenicity Of The Heat Shock Protein, Hsp60 Of Brucella Abortus , Dennis Gor Jan 1994

Characterization And Immunogenicity Of The Heat Shock Protein, Hsp60 Of Brucella Abortus , Dennis Gor

Retrospective Theses and Dissertations

Brucella abortus is the causative agent of bovine brucellosis, a disease that causes spontaneous abortion in cows. The most effective form of protection against this pathogen is immunization; however, Brucella abortus strain 19 (the standard vaccine against Brucella abortus) is not completely protective. The vaccination of laboratory mice with the heat shock protein, hsp60 derived from Brucella abortus, using live attenuated recombinant Salmonella typhimurium expressing this protein (hsp60) as a delivery system, and the characterization of the immune response to Brucella abortus hsp60 over a 12 week time course following vaccination is described;Infection of BALB/c strain of laboratory ...


Identification Of Potential Oat Phytochrome A Mrna Degradation Mechanisms , David Charles Higgs Jan 1994

Identification Of Potential Oat Phytochrome A Mrna Degradation Mechanisms , David Charles Higgs

Retrospective Theses and Dissertations

The phytochrome plant photoreceptor is important for perceiving the light environment and initiating plant developmental and environmental responses. When dark-grown oat seedlings are treated with light the phytochrome A (PHYA) mRNA abundance rapidly declines due, in part, to the inherent instability of the PHYA mRNA. Messenger RNA stability is an important process in regulating eukaryotic gene expression. My primary goal was to investigate both the mechanism of oat PHYA mRNA degradation and cis-acting sequences involved in regulating oat PHYA mRNA degradation. An oat protoplast system was established to investigate its use as a quick and reliable system to study plant ...


G-Wires: The Growth And Characterization Of A G4-Dna Nanostructure , Thomas Cosgrove Marsh Jan 1994

G-Wires: The Growth And Characterization Of A G4-Dna Nanostructure , Thomas Cosgrove Marsh

Retrospective Theses and Dissertations

Guanine-rich sequences are vital components in the genomes of many organisms. For example, G-rich sequences are found in telomeres, fragile X locus, promoters, IgG switch regions, recombinational hot spots and the HIV RNA dimerization domain. The functions of these G-rich sequences rely in part on guanine self-recognition. G-rich sequences can adopt a quadruple helical conformation in the presence of specific monovalent and divalent metal cations which are also required for maintaining the quadruplex stability. The structural basis of the quadruplex is a cyclic Hoogsteen hydrogen bonded guanine tetrad known as the G-quartet. Sequences capable of forming G-quartets are classified as ...