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Articles 31 - 51 of 51

Full-Text Articles in Molecular Biology

Integration Specificity Of The Retrovirus-Like Transposable Element Ty5 Of Saccharomyces , Sige Zou Jan 1996

Integration Specificity Of The Retrovirus-Like Transposable Element Ty5 Of Saccharomyces , Sige Zou

Retrospective Theses and Dissertations

The retrotransposons and retroviruses display a strong preference in selecting integration sites. The molecular mechanisms underlying this process, however, are largely unknown. I have characterized a new retrotransposon, called Ty5, in diverse strains of Saccharomyces cerevisiae and related species. A functional element, Ty5-6p, was identified from S. paradoxus. To investigate Ty5 target preference, the locations of 13 native insertions were determined in S. cerevisiae and S. paradoxus. Twelve were found near the telomeres and the mating locus HMR. To determine if this distribution is a consequence of targeted integration, a Ty5 transposition assay was developed in S. cerevisiae using Ty5-6p ...


Molecular Analyses Of Group 1 Late Embryogenic Abundant (Lea) Genes In Soybean (Glycine Max (L.) Merr.) , Éberson Sanches Calvo Jan 1995

Molecular Analyses Of Group 1 Late Embryogenic Abundant (Lea) Genes In Soybean (Glycine Max (L.) Merr.) , Éberson Sanches Calvo

Retrospective Theses and Dissertations

The entire soybean Sle gene family was cloned and characterized. The five Sle genes (Sle1-5) could be divided into two classes based on sequence identity. Sle1-4 map to 4 different linkage groups. Sle1 and Sle5 are expressed weeks earlier in seed development than Sle2 and Sle3. Sle4 is a pseudogene. Maximal levels of Sle mRNA accumulate in the seeds, before desiccation had occurred, and decline rapidly upon seed imbibition. Desiccation does not induce Sle expression in seeds. Unlike most of its homologs, ABA is not necessary to induce Sle expression in cultured embryos and only moderately increases Sle mRNA levels ...


Identification And Characterization Of G4-Dna Binding Proteins From Tetrahymena Thermophila , Ted Patrick Schierer Jan 1995

Identification And Characterization Of G4-Dna Binding Proteins From Tetrahymena Thermophila , Ted Patrick Schierer

Retrospective Theses and Dissertations

Alternative DNA conformations have been known to exist since before the elucidation of the double helix. The study of alternative DNA conformations formed by telomeric sequences has led to detailed studies of biologically relevant DNA capable of forming unusual structures. In order to understand the biological role of alternative DNA conformations formed by telomeric DNA, proteins which bind these structures have been identified and characterized;The initial portion of my research involved the identification of a protein from Tetrahymena thermophila which binds preferentially to parallel-stranded G-quartet structures. Competition and binding assays demonstrated that the protein, TGP (Tetrahymena G4 binding protein ...


Calsensin, A Novel Calcium-Binding Protein Expressed In A Subset Of Peripheral Leech Neurons Fasciculating In A Single Axon Tract , Kristen Kay Briggs Jan 1995

Calsensin, A Novel Calcium-Binding Protein Expressed In A Subset Of Peripheral Leech Neurons Fasciculating In A Single Axon Tract , Kristen Kay Briggs

Retrospective Theses and Dissertations

The lan 3-6 monoclonal antibody recognizes a subpopulation of peripheral neurons whose afferents segregate into a single fascicle within the developing leech central nervous system. The lan 3-6 monoclonal antibody was used to isolate a clone encoding a novel protein, calsensin, which contains two EF-hand calcium-binding domains. In situ hybridizations with calsensin riboprobes, Western blots of lan 3-6 monoclonal antibody immunoprecipitations, and immunohistochemistry with polyclonal antibodies generated against a partially-purified calsensin fusion protein confirmed that the sequence encoding the lan 3-6 antigen has been identified. Partially-purified calsensin fusion protein binds [superscript]45Ca[superscript]2+ in vitro, suggesting that the calsensin ...


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 ...


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 ...


Telomeric Nucleic Acids: C-Strand Structure And A Telomerase Rna Mutant , Shawn Cameron Ahmed Jan 1994

Telomeric Nucleic Acids: C-Strand Structure And A Telomerase Rna Mutant , Shawn Cameron Ahmed

Retrospective Theses and Dissertations

Telomeres, the ends of linear chromosomes, are composed of simple tandem repeats which are usually G·C rich. Telomeres are essential for chromosome stability, organizing the nuclear architecture and ensuring complete replication of the chromosomal terminus. To understand how telomeres carry out these fundamental cellular roles, one must understand the structural and dynamic properties of telomeric repeat sequences. Structural and genetic approaches were taken to learn more about telomeric nucleic acids;The structural portion of my research concerned an unusual DNA structure formed by the C-rich strand of telomeric DNA. Telomeric C-strand sequences form non-Watson-Crick structures in supercoiled plasmids at ...


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 ...


Soybean Cultivar Development: A Genome Perspective , Lisa Lou Lorenzen Jan 1994

Soybean Cultivar Development: A Genome Perspective , Lisa Lou Lorenzen

Retrospective Theses and Dissertations

The purpose of this dissertation was to retrospectively analyze the process of soybean cultivar development from a molecular perspective, by following the inheritance of RFLP markers in a pedigree analysis. Five methods of analysis are included in this dissertation;Sixty-four plant introductions, cultivars, and breeding lines were analyzed to define a core set of 97 probes with a high likelihood of detecting a polymorphism in elite germplasm. The ability to trace regions of chromosomes from parent to offspring and the application of pedigree-based mapping was demonstrated, which is the cosegregation of phenotypic traits and RFLP markers based on pedigree information ...


Cloning, Sequencing, And Expression Of Brucella Abortus Heat Shock 70 Gene , Emily C. L. Chin Jan 1993

Cloning, Sequencing, And Expression Of Brucella Abortus Heat Shock 70 Gene , Emily C. L. Chin

Retrospective Theses and Dissertations

Brucella abortus is a gram negative bacteria that can infect and cause serious disease in many mammals including humans. Any organism, including Brucella, that can survive as an intracellular parasite must be able to survive the stress of a foreign and often hostile environment of the host. Stress usually results in a dramatic change in gene expression including an elevated synthesis of heat shock proteins;We have subcloned, sequenced and expressed the Brucella HSP70 and the upstream sequences. The gene was put under the control of the strong "tac" promoter. However, when expressed, we saw a high accumulation of a ...


Molecular Analysis Of Protein Kinase C In The Sea Urchin Lytechinus Pictus , Terese Louise Rakow Jan 1993

Molecular Analysis Of Protein Kinase C In The Sea Urchin Lytechinus Pictus , Terese Louise Rakow

Retrospective Theses and Dissertations

Protein kinase C (PKC) was originally described as a serine threonine kinase in brain tissue. This activity was found to be dependent upon Ca[superscript]2+ and phosphatidyl serine. Today protein kinase C consists of a family of kinases with nine known members. Some members are Ca[superscript]2+-independent isozymes, and all of them have subtle activation differences. The multiple isozymes with varying activities in addition to different tissue distributions lead to the idea that members of the family have different functions. PKC has been well studied in mammalian systems and it is concluded that PKC is activated in ...


Cloning And Molecular Characterization Of Two Nuclear Genes For Zea Mays Mitochondrial Chaperonin 60 , Pamela Sue Close Jan 1993

Cloning And Molecular Characterization Of Two Nuclear Genes For Zea Mays Mitochondrial Chaperonin 60 , Pamela Sue Close

Retrospective Theses and Dissertations

Hsp60 is a mitochondrial protein first identified in Tetrahymena thermophila and Saccharomyces cerevisiae. It belongs to a class of proteins called "molecular chaperones" which prevent aggregation and precipitation of partially or completely unfolded polypeptides;Two cDNAs for maize cpn60 were identified and sequenced. Southern blots of maize DNA showed two bands hybridizing with mt-cpn60 in maize inbreds. One copy was present in Arabidopsis. Both maize genes are contained within the nuclear genome. The chromosomal location of the cpn60 genes have been mapped by RFLPs. A maize B73 genomic library has been constructed and screened for cpn60 clones and two major ...


Characterization Of Cis-Acting Replication Control Elements In Ribosomal Rna Genes Of Tetrahymena Thermophila , Wen-Ling Shaiu Jan 1993

Characterization Of Cis-Acting Replication Control Elements In Ribosomal Rna Genes Of Tetrahymena Thermophila , Wen-Ling Shaiu

Retrospective Theses and Dissertations

This dissertation describes the identification and characterization of specific cis-acting replication control elements in the replication origin of Tetrahymena rDNA. Earlier studies of a mutant rDNA allele, C3-rmm1, identified a cis-acting sequence (the Type I repeat) within the 5[superscript]' non-transcribed spacer of rDNA that affects rDNA replication (Larson et al. 1986). Characterization of two additional, independently-isolated mutants (C3-rmm3 and C3-rmm4) and a revertant of C3-rmm4 strongly argue that the Type I repeat is indeed a cis-acting replication control element. Mutations causing rDNA replication defects were identified in copies of the Type I repeat that are separated by >600 bp ...


Safety And Potency Testing Of Veterinary Vaccines , Louise Mary Henderson Jan 1993

Safety And Potency Testing Of Veterinary Vaccines , Louise Mary Henderson

Retrospective Theses and Dissertations

Prior to licensing of veterinary vaccines, it is essential to demonstrate that the use of the product is safe (e.g., use of the product will not have unexpected or undesirable effects on animals exposed to the agent or on the environment) and potent (e.g., produces the desired result). The projects described in this dissertation demonstrate research directed toward the development and improvement of safety and potency testing of veterinary vaccines from a regulatory perspective;In the first study, recombination between vaccine strains of pseudorabies virus (PRV) resulting in the creation of strains with undesirable virulence and antigenic combinations ...


Characterization Of Dna-Binding Proteins That Recognize The Replication Origin Of The Rrna Genes Of Tetrahymena Thermophila , Angela Rae Umthun Jan 1993

Characterization Of Dna-Binding Proteins That Recognize The Replication Origin Of The Rrna Genes Of Tetrahymena Thermophila , Angela Rae Umthun

Retrospective Theses and Dissertations

Proteins that bind to specific sequences in replication origins have been shown to be important components of both prokaryotic and eukaryotic DNA replication systems. An origin of DNA replication is located within the 5[superscript]' non-transcribed spacer region of the rRNA genes (rDNA) of Tetrahymena thermophila. Previous work has shown that several cis-acting mutations responsible for rDNA replication defects lie in upstream repeats of a transcriptional promoter element, the Type I repeat;Using FE(II)EDTA cleavage footprinting and gel-mobility shift assays, I identified and characterized two distinct DNA-binding activities that interact with the Type I repeat. One of these ...


Deletion Analysis Of The Starch Binding Domain From Aspergillus Glucoamylase , Luojing Chen Jan 1992

Deletion Analysis Of The Starch Binding Domain From Aspergillus Glucoamylase , Luojing Chen

Retrospective Theses and Dissertations

Glucoamylase (GA) from Aspergillus (EC 3.2.1.3) exists in two forms: GAI (amino acids 1-616) and GAII (amino acids 1-512). GAII is identical to GAI but lacks the C-terminal region (amino acids 513-616). While both forms of glucoamylase are able to digest soluble starch, only GAI has the ability to bind to and therefore hydrolyze native starch granules. To further examine the location of the starch binding domain at the C-terminus of GAI and to determine how many amino acid residues of GAI are required for starch binding, six [beta]-galactosidase fusion proteins were constructed. Affinity purified fusion ...


Direct Introduction Of Dna Into Embryonic Axes Of Glycine Max By Microprojectile Bombardment , Charisse Marie Buising Jan 1992

Direct Introduction Of Dna Into Embryonic Axes Of Glycine Max By Microprojectile Bombardment , Charisse Marie Buising

Retrospective Theses and Dissertations

Apical meristem and axillary bud development in germinating soybean embryonic axes treated for 24 hr with the cytokinin, 6-benzylaminopurine (BAP) seemed normal morphologically, but was delayed by about 9 to 15 hr. After 5 days, numerous, rapidly proliferating meristematic regions (de novo vegetative buds) were observed in BAP-treated axes around the perimeter of the apical dome. These visible changes were preceded by transient inhibition of DNA synthesis in the shoot apices as early as 21-36 hr post-imbibition;Some of the new meristematic regions developed into multiple shoots, which were excised, subcultured, and used to generate mature plants. In the absence ...


Physical Mapping Of Rhizobium Meliloti And Glycine Max L. (Merr.) Using Pulsed-Field Gel Electrophoresis , Rhonda Jean Honeycutt Jan 1991

Physical Mapping Of Rhizobium Meliloti And Glycine Max L. (Merr.) Using Pulsed-Field Gel Electrophoresis , Rhonda Jean Honeycutt

Retrospective Theses and Dissertations

Partial physical maps of each of the three replicons of Rhizobium meliloti were constructed using restriction enzymes PacI, SpeI, and AseI. Using transverse alternating field gel electrophoresis (TAFE) in combination with very long pulse times, low agarose concentrations, and low field gradients, or in combination with PacI restriction enzyme digestions, the three replicons of R. meliloti 1021 were separated. Three bands were separated from undigested genomic DNA samples using TAFE; Southern hybridizations with representative cloned genes from each replicon revealed that each band corresponded to one of the replicons. The three bands were excised, digested with SpeI, and separated using ...


Analysis Of Three Plasmids From Filamentous, Nitrogen-Fixing Cyanobacteria , Douglas Kevin Walton Jan 1991

Analysis Of Three Plasmids From Filamentous, Nitrogen-Fixing Cyanobacteria , Douglas Kevin Walton

Retrospective Theses and Dissertations

The cyanobacteria are an ancient and diverse group of prokaryotes capable of oxygenic photosynthesis. They display both unicellular and filamentous cell types and some have the ability to fix atmospheric dinitrogen, and the ability to differentiate specialized cells. In addition, many of the cyanobacteria possess plasmids. To date, only one plasmid, from a unicellular non-nitrogen-fixer, has been characterized in detail. The current lack of information concerning cyanobacterial plasmids, and their subsequent use as vectors, has hindered genetic analysis, particularly in the filamentous species;In this study, the properties of two plasmids and one plasmid origin of replication from filamentous, nitrogen-fixing ...


Study Of En At The Wx-844 Allele: Modifier Of En Excision, Weak En, And Transposition Of En , Sudhansu Dash Jan 1991

Study Of En At The Wx-844 Allele: Modifier Of En Excision, Weak En, And Transposition Of En , Sudhansu Dash

Retrospective Theses and Dissertations

The wx-844 allele contains a fully active and complete En transposable element inserted within the Wx gene. The mutability of this allele is very high and the somatic mutability is seen in the endosperm as dark staining Wx sectors in a background of non-staining wx regions;The very high coarse pattern of waxy mutability is modified into a reduced fine pattern in the presence of the I-102 element located within the A gene in the non-autonomously mutable a-m(r) 102 allele. The modifying effect of the I-102 element on En induced excision has been found to be a general phenomenon ...


Identification Of The Immediate-Early Products Of Bovine Herpesvirus-1 , David A. Hulce Jan 1990

Identification Of The Immediate-Early Products Of Bovine Herpesvirus-1 , David A. Hulce

Retrospective Theses and Dissertations

Bovine herpesvirus-1 (BHV-1) is a member of the alphaherpesvirinae. Productive infections of the alphaherpesvirinae progress through three stages of viral transcription and translation. The first stage, immediate-early (IE), does not require prior viral gene expression and is required for the second, delayed-early (DE), and third, late (L), stages of the infectious cycle. Like other herpesviruses, BHV-1 frequently establishes latent infections. This study was undertaken to characterize the IE stage of the productive BHV-1 infection. The number and location of IE genes and the size of IE polypeptides and IE mRNAs were investigated;Probing genomic Southern blots of BHV-1 cloned in ...