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1994

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Articles 1 - 30 of 39

Full-Text Articles in Molecular 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 Articles

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 Articles

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 ...


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 ...


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.


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.


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.


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 ...


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 ...


Mitochondrial Dna Variation In Natural And Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck) And The Calico Scallop, Argopecten Gibbus (Dall), Sandra Grace Blake Jan 1994

Mitochondrial Dna Variation In Natural And Cultured Populations Of The Bay Scallop, Argopecten Irradians (Lamarck) And The Calico Scallop, Argopecten Gibbus (Dall), Sandra Grace Blake

Dissertations, Theses, and Masters Projects

No abstract provided.


Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel Jan 1994

Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel

Open Dartmouth: Faculty Open Access Articles

Chromatin in eukaryotic nuclei is thought to be partitioned into functional loop domains that are generated by the binding of defined DNA sequences, named MARs (matrix attachment regions), to the nuclear matrix. We have previously identified B-type lamins as MAR-binding matrix components (M. E. E. Ludérus, A. de Graaf, E. Mattia, J. L. den Blaauwen, M. A. Grande, L. de Jong, and R. van Driel, Cell 70:949-959, 1992). Here we show that A-type lamins and the structurally related proteins desmin and NuMA also specifically bind MARs in vitro. We studied the interaction between MARs and lamin polymers in molecular ...


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.


Xenopus Laevis Ribosomal Protein S1: Evidence For Regulation At The Transcriptional Level, Cleve Ray-Dean Sinor Jan 1994

Xenopus Laevis Ribosomal Protein S1: Evidence For Regulation At The Transcriptional Level, Cleve Ray-Dean Sinor

Dissertations, Theses, and Masters Projects

No abstract provided.


Regulation Of Mitogen Regulated Protein/Proliferin Gene Expression In 3t3 Cells By Basic Fibroblast Growth Factor , Manzoor Ali P. K. Mohideen Jan 1994

Regulation Of Mitogen Regulated Protein/Proliferin Gene Expression In 3t3 Cells By Basic Fibroblast Growth Factor , Manzoor Ali P. K. Mohideen

Retrospective Theses and Dissertations

Mitogen regulated protein/proliferin (MRP/PLF) is a murine uterine growth factor belonging to the prolactin/growth hormone gene superfamily. Basic fibroblast growth factor (bFGF) regulates its expression in 3T3 cells and is speculated to be among its regulators in vivo. In order to gain insights into its regulation, experiments were performed to elucidate the mechanisms by which bFGF regulates mrp/plf gene expression in 3T3 cells. RT-PCR analyses demonstrated that of the three different forms of MRP/PLF proteins only one, PLF1, is expressed in these cells in response to bFGF. PLF1 could be the product of either plf42 ...


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 ...


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 And Ultrastructural Aspects Of The Adaptation Of Chlamydomonas Reinhardtii To Limiting Co2 , Anne Margaret Geraghty Jan 1994

Molecular And Ultrastructural Aspects Of The Adaptation Of Chlamydomonas Reinhardtii To Limiting Co2 , Anne Margaret Geraghty

Retrospective Theses and Dissertations

Change occurring in Chlamydomonas reinhardtii as cells adapt to limiting CO2 conditions were examined at both a molecular level and an ultrastructural level. It was demonstrated using antibodies that the time course of the de novo synthesis of LIP-21, a 21 kD limiting-CO2 induced polypeptide, correlates with the appearance of CO2 concentrating activity and that expression of the nuclear gene for LIP-21 is regulated at the level of translatable message. These results are consistent with LIP-21 being a component of an adaptive response to limiting CO2, such as the induction of the CO2 concentrating mechanism. Phase separation of membrane proteins ...


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 ...


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 ...