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

Genetic And Biochemical Analysis Of Aspergillus Awamori Glucoamylase Thermostability , Martin John Allen Jan 1997

Genetic And Biochemical Analysis Of Aspergillus Awamori Glucoamylase Thermostability , Martin John Allen

Retrospective Theses and Dissertations

Aspergillus awamori glucoamylase (GA) is an enzyme involved in industrial corn starch processing. Genetic and biochemical approaches were used to study the mechanisms governing GA thermostability. Three proline substitution (Xaa → Pro) mutations were constructed that were predicted to increase the enzyme's stability by decreasing its conformational entropy of unfolding. When expressed in Saccharomyces cerevisiae Ser30 → Pro increased, Asp345 → Pro did not alter and Glu408 → Pro greatly decreased GA stability as measured by resistance to irreversible thermoinactivation relative to the wild-type enzyme. The Ser30 → Pro mutation was combined with other previously identified stabilizing mutations to examine whether combining such mutations ...


Pou Domain Genes And The Immunoglobulin Octamer Motif In Chickens , Lynn Marie Heltemes Jan 1997

Pou Domain Genes And The Immunoglobulin Octamer Motif In Chickens , Lynn Marie Heltemes

Retrospective Theses and Dissertations

This research was undertaken to test the hypothesis that multiple POU genes exist and that POU proteins are involved in transcriptional regulation in the chicken. The POU protein Oct-2 has been hypothesized to partially regulate immunoglobulin gene expression through its interaction with the octamer motif found in the promoter of immunoglobulin genes. Transcriptional regulation of immunoglobulin genes provides a model for tissue-specific gene expression in the immune system. In searching for a chicken Oct-2 homologue, two partial chicken POU domain genes were identified. A cDNA clone encoding the POU domain of Brn-3a was isolated and showed near identity to the ...


Identification Of Genes In Tn916 Encoding Membrane-Targeted Proteins, Suganda Loe Jan 1997

Identification Of Genes In Tn916 Encoding Membrane-Targeted Proteins, Suganda Loe

Retrospective Theses and Dissertations

Tn916 is a 18 kb, broad-host range conjugative transposon originally isolated from Enterococcus faecalis. Transposon TnphoA was used to identify genes in Tn916 encoding for membrane-targeted proteins or for secretion. Sixty five independent PhoA+ gene fusions were isolated. These insertions clustered into two regions, open reading frames 13 and 15 (Flanagan et al., Plasmid 32:350-354). These TnphoA insertional mutations in resulted in a Tn+ (ability to transpose intracellularly) and Tra- (inability to transfer conjugatively) phenotype. The hydrophathy analysis of ORF13 and ORF15 revealed that these proteins lack the classical signal peptides necessary for protein export, suggesting that these two ...


Improved Resins And Novel Materials And Methods For Solid Phase Extraction And High Performance Liquid Chromatography , Ronald Carl Freeze Jan 1997

Improved Resins And Novel Materials And Methods For Solid Phase Extraction And High Performance Liquid Chromatography , Ronald Carl Freeze

Retrospective Theses and Dissertations

Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. By reducing the size of the resin beads and optimizing reaction conditions, resins were produced which had excellent capacities both in the packed-column and the suspension mode. By reducing bead sizes to 1 [mu]m, direct injection of the beads into an inductively coupled plasma (ICP) torch was possible. The resin, along with adsorbed metals, was vaporized ...


Gene Expression Studies Of Murine Pregnancy Associated Granulated Metrial Gland And Decidual Cells , Melissa Phillips Allen Jan 1997

Gene Expression Studies Of Murine Pregnancy Associated Granulated Metrial Gland And Decidual Cells , Melissa Phillips Allen

Retrospective Theses and Dissertations

During pregnancy in viviparous mammals, the maternal decidua develops between the embryo and the uterine endometrium. This dissertation describes research on two different cell types present within the rodent decidua during pregnancy, namely, granulated metrial gland (GMG) cells and decidual cells;GMG cells are natural killer cells that proliferate and differentiate within the murine uterus during pregnancy. Their differentiation is associated with the accumulation of cytolytic mediators within cytoplasmic granules. The signaling mechanisms required for GMG cell differentiation, however, are largely unknown. In this study, expression of the genes coding for granzymes D, E, F, and G (granzymes D-G) was ...


Molecular Cloning And Characterization Of Gl8, A Gene Involved In Maize Cuticular Wax Biosynthesis , Xiaojie Xu Jan 1997

Molecular Cloning And Characterization Of Gl8, A Gene Involved In Maize Cuticular Wax Biosynthesis , Xiaojie Xu

Retrospective Theses and Dissertations

The gl8 locus of maize was previously defined by a mutation that reduces the amount and alters the composition of seedling cuticular waxes. Sixty independently derived gl8 mutant alleles have been isolated from stocks that carried the Mutator transposon system. A DNA fragment that contains a Mu8 transposon and that co-segregates with one of these alleles, gl8-Mu3142, was identified and cloned. DNA flanking the Mu8 transposon was shown to represent the gl8 locus via allelic cross-referencing experiments. The gl8 probe reveals a 1.4-kb transcript present in wild-type seedling leaves, and in lesser amounts, in other organs and at other ...


Differential Glycosylation Of Tractin And Leechcam, Two Novel Ig-Superfamily Members, Regulates Neurite Extension And Fascicle Formation , Yueqiao Huang Jan 1997

Differential Glycosylation Of Tractin And Leechcam, Two Novel Ig-Superfamily Members, Regulates Neurite Extension And Fascicle Formation , Yueqiao Huang

Retrospective Theses and Dissertations

Specific carbohydrate structures on neural cell adhesion molecules are promising candidates for assisting in patterning neural connections during development. An excellent system to study the potential function of specific oligosaccharide modifications of neural proteins regulating pathway formation is in the projections of sensillar neurons in leech. At least five different monoclonal antibodies (Lan3-2, Lan2-3, Lan4-2, Laz2-369, Laz7-79) which recognize different glycoepitopes specific to the entire population as well as distinct subsets of these sensillar neurons have been identified. Their expression patterns and antibody perturbation studies are consistent with the hypothesis that a hierarchy of distinct carbohydrate structures expressed by specific ...


Monitoring Protein Refolding Using Diverse Separation And Spectroscopy Techniques , Pamela Kay Jensen Jan 1997

Monitoring Protein Refolding Using Diverse Separation And Spectroscopy Techniques , Pamela Kay Jensen

Retrospective Theses and Dissertations

Rapid growth in the biotechnology industry has led to a dramatic increase in attention to the protein folding problem. Understanding of protein folding is essential to the production of biopharmaceuticals since commercial production of recombinant proteins often requires a protein refolding process to recover high yields;Capillary zone electrophoresis (CZE) equipped with laser induced fluorescence detection (LIFD) is developed as a tool for monitoring the refolding of a model protein, phage P22 tailspike endorhamnosidase. Intermediates on the folding pathway are separated in CZE and monitored by their intrinsic tryptophan fluorescence. Monitoring refolding of tailspike by traditional methods, sodium dodecyl sulfate-polyacrylamide ...


Structure-Function Study Of A Plant Protein Proteinase Inhibitor: Site-Directed Mutagenesis Of Cucurbita Maxima Trypsin Inhibitor V , R. Sandra Benavente Jan 1997

Structure-Function Study Of A Plant Protein Proteinase Inhibitor: Site-Directed Mutagenesis Of Cucurbita Maxima Trypsin Inhibitor V , R. Sandra Benavente

Retrospective Theses and Dissertations

Cucurbita marima Trypsin Inhibitor-V (CMTI-V), isolated from pumpkin, is an inhibitor of trypsin and [beta]-Factor XIIa (FXIIa). CMTI-V binds to enzyme as would a substrate, but whereas substrate is cleaved at its scissile bond and the resulting fragments released, CMTI-V remains bound to its target enzyme, thus inhibiting activity. Amino acids at the amino side of the scissile bond are referred to as P1, P2, etc., away from the bond. Carboxyl-side amino acids are referred to as P1', P2', etc., away from the bond. We focused on the inhibitor amino acid positions P1' (D45) and P3 (V42). CMTI-V belongs ...


Molecular Characterization Of Cer2, An Arabidopsis Gene Involved In Cuticular Wax Accumulation , Yiji Xia Jan 1997

Molecular Characterization Of Cer2, An Arabidopsis Gene Involved In Cuticular Wax Accumulation , Yiji Xia

Retrospective Theses and Dissertations

Cuticular waxes are complex mixtures of very long chain fatty acids (VLCFAs) and their derivatives. The CER2 locus of Arabidopsis is involved in cuticular wax accumulation on stems, siliques, and hypocotyls. The CER2 gene was cloned via chromosome walking. This cloned sequence is able to complement the cer2 mutant phenotype. It is a single-copy sequence in the Arabidopsis genome and encodes a novel protein with a predicted mass of 47 kD. Anti-CER2 polyclonal antibodies detected a 47 kD polypeptide. Cell fractionation and immunoblot analyses demonstrated that the CER2 protein is not membrane-bound and localized in nuclei. These results suggest that ...


Regulation Of Brucella Abortus Catalase As A Defensive Mechanism Against Oxidative Stress , Jeonga Kim Jan 1997

Regulation Of Brucella Abortus Catalase As A Defensive Mechanism Against Oxidative Stress , Jeonga Kim

Retrospective Theses and Dissertations

Free radicals in the nature are harmful to organisms because they cause damage to tissues, cell membranes, proteins, and DNA. The animal immune system (cell mediated immune response) uses oxygen molecules to kill foreign organisms. B. abortus causes a cattle disease called brucellosis. The mechanism for bacteria to survive and adapt in the face of oxidative attack is thought to be important for understanding pathogenesis. This dissertation presents the response of B. abortus to oxidative stress and the regulation of catalase as a defensive mechanism;Different protein expression patterns were observed during oxidative stress by conducting 2-D protein gel analysis ...


Host Regulation Of The Replication Of The Yeast Retrotransposon Ty5 , Ning Ke Jan 1997

Host Regulation Of The Replication Of The Yeast Retrotransposon Ty5 , Ning Ke

Retrospective Theses and Dissertations

The replication of retroelements may have deleterious effects on the hosts. Therefore, elements and their hosts have coevolved mechanisms to regulate retroelement replication. This regulation can occur at the transcriptional, translational, or post-translational levels as well as through targeted integration or cDNA recombination. I have studied host regulation of the Saccharomyces retrotransposon Ty5. I have found that Ty5 transcription is carefully controlled. Transcription of Ty5 is haploid specific and is repressed 10 fold in diploid strains. Ty5 transcription is also regulated by the pheromone response pathway, which is activated during mating. In addition, Ty5 transcription is regulated by flanking sequences ...


Sequence And Functional Analysis Of The P97 Swine Cilium Adhesin Gene Of Mycoplasma Hyopneumoniae , Tsungda Hsu Jan 1997

Sequence And Functional Analysis Of The P97 Swine Cilium Adhesin Gene Of Mycoplasma Hyopneumoniae , Tsungda Hsu

Retrospective Theses and Dissertations

Mycoplasma hyopneumoniae causes swine enzootic pneumonia, an important disease in the swine industry. Adherence of M. hyopneumoniae to the cilia of the tracheal epithelial cells is required to establish infection. Previous studies have identified a 97-kDa protein (P97) as the putative ciliary adhesin. To further characterize the P97 protein, the gene has been cloned, its DNA sequence analyzed, and the function of the P97 protein expressed in Escherichia coli studied. These results demonstrated that recombinant P97 has swine ciliary adherence activity. Further analysis revealed that the P97 gene was translated as a 124.9-kilodalton (kDa) protein and subjected to proteolytic ...


Studies Of Cis- And Trans-Acting Elements In Tetrahymena Rdna Replication , Chunying Du Jan 1997

Studies Of Cis- And Trans-Acting Elements In Tetrahymena Rdna Replication , Chunying Du

Retrospective Theses and Dissertations

Eukaryotic cells must precisely duplicate their genomes before they divide. The mechanisms of eukaryotic chromosomal DNA replication are far from clear, however, because very few cis- and trans-acting factors that function in eukaryotic DNA replication have been identified. To gain further insights into this problem, this work identified and characterized potential cis- and trans-acting replication factors for the replication initiation of Tetrahymena ribosomal RNA gene (rDNA);A search far cis-acting elements identified a cluster of predicted modular sequences and structural elements in the origin region of rDNA. The presence of these elements were verified experimentally; (1) two mung bean nuclease-hypersensitive ...


Cloning And Characterization Of A Soybean Snf2 Yeast Homolog , Weiping Chen Jan 1997

Cloning And Characterization Of A Soybean Snf2 Yeast Homolog , Weiping Chen

Retrospective Theses and Dissertations

It is of great economic and scientific interest to understand plant disease resistance genes at the molecular level. Phytophthora sojae, a fungal pathogen of soybean is of particular interest since the root and stem rot resulting from its infection causes great economic loss. It is the goal of this project to clone Phytophthora resistance genes from soybean. This was done by designing primers from the conserved regions of known plant disease resistance genes using a modified differential display for near isogenic lines; L85-3044 a resistant line and Williams, a susceptible line. Several polymorphic bands were identified, including a unique 0 ...


Analyses Of A Genic Male-Sterile Mutant In Soybean , Wei Jin Jan 1997

Analyses Of A Genic Male-Sterile Mutant In Soybean , Wei Jin

Retrospective Theses and Dissertations

A new genic male-sterile mutant in soybean was characterized genetically, developmentally, and molecularly. This mutant is controlled by a single recessive gene, which is not allelic to six previously identified soybean genic male-sterile mutants: ms1, ms2, ms3, ms4, ms5, or ms6. No linkage was detected between the male-sterile gene and flower color (W1 locus), or between the male-sterile gene and pubescence color (T1 locus). Developmental and enzymatic studies showed that sterility was caused by retention of the callose walls, which normally are degraded by callase ([beta]-1,3-glucanase) at the late tetrad stage. Molecular markers linked with the male-sterile gene ...


Study Of Avian Acyl-Coa Cholesterol Acyltransferase , Donghui Cheng Jan 1997

Study Of Avian Acyl-Coa Cholesterol Acyltransferase , Donghui Cheng

Retrospective Theses and Dissertations

Acyl-CoA Cholesterol Acyltransferase (ACAT) (EC.2.3.1.26) catalyzes intracellular esterification of cholesterol with long chain fatty acyl-CoA. ACAT is an integral membrane protein of the endoplasmic reticulum membrane and plays a very important role in intracellular cholesterol homeostasis. Activity of ACAT is important for the production and secretion of lipoproteins and for intestinal absorption of dietary cholesterol. The involvement of ACAT activity in the pathogenesis of atherosclerosis and its related heart diseases leads to an extensive effort from both the pharmaceutical industry and the basic research community to study this protein and its catalytic mechanism. ACAT from yolk ...


Cloning, Expression And Bioactivity Of Porcine Soluble Tnf Receptor 1 And The Comparison Of Pk(15) And Wehi 164(13)-Based Tnf Bioassays , Nancy A. Maroushek Boury Jan 1997

Cloning, Expression And Bioactivity Of Porcine Soluble Tnf Receptor 1 And The Comparison Of Pk(15) And Wehi 164(13)-Based Tnf Bioassays , Nancy A. Maroushek Boury

Retrospective Theses and Dissertations

Tumor necrosis factor (TNF) is a pro-inflammatory cytokine that activates both leukocytes and endothelium and facilitates the movement of inflammatory cells from circulation to sites of infection or injury. This activation may be beneficial and aid in host defense, or may be detrimental and mediate part of the pathophysiology of disease. Several porcine diseases, such as salmonellosis and mycoplasmal pneumonia, cause an increase in TNF production, which may be either beneficial or harmful to swine health. Two related studies were completed to develop assays and reagents to further study the role of TNF in porcine disease;In the first study ...


Suppressor Analysis Of The Protein Kinase Elm1p, An Enzyme Involved In The Regulation Of Yeast Morphology , Nicholas Patrick Edgington Jan 1997

Suppressor Analysis Of The Protein Kinase Elm1p, An Enzyme Involved In The Regulation Of Yeast Morphology , Nicholas Patrick Edgington

Retrospective Theses and Dissertations

Saccharomyces cerevisiae is an ascomycete that has several developmental options, with concomitant morphological changes, that depend on cell type and nutrient status. In response to these signals, vegetative Saccharomyces cerevisiae cells assume one of two distinct morphologies, the yeast form or the filamentous form. Molecules affecting this morphogenetic response were identified by analyzing transposon-induced or spontaneous suppressor mutations that restore yeast form growth to a strain that constitutively exhibits filamentous form characteristics owing to mutation of the protein kinase Elm1p. One transposon-tagged mutation was isolated and is allelic to the negative regulatory subunit Bcy1p, thus activation of cAMP dependent protein ...


Identification And Characterization Of Proteins Binding To Regulatory Elements Of The Hoxa-5 Spatial-Specific Enhancer , Tamara Mann Nowling Jan 1997

Identification And Characterization Of Proteins Binding To Regulatory Elements Of The Hoxa-5 Spatial-Specific Enhancer , Tamara Mann Nowling

Retrospective Theses and Dissertations

The Hox homeobox genes cooperate in providing positional information needed for spatial and temporal patterning of the vertebrate body axis. However, the biological mechanisms behind spatial Hox expression are largely unknown. In transgenic mice, gene fusions between Hoxa-5 (previously called Hox-1.3) 5' flanking regions and lacZ show tissue- and time-specific expression in the brachial spinal cord in day 11-13 embryos. This spatially-specific expression is directed by a 604 bp regulatory region with enhancer properties. Fine-detail mapping of this enhancer has identified several elements involved in region-specific expression. A brachial spinal cord (BSC) element, is required for expression in the ...


Organization And Expression Of The Tup Gene In Daucus Carota , Philip Earl Dykema Jan 1997

Organization And Expression Of The Tup Gene In Daucus Carota , Philip Earl Dykema

Retrospective Theses and Dissertations

Differential screening of a somatic embryo cDNA library for genes expressed during embryogenesis has disclosed a small RNA which I have named Tiny Up-regulated Protein (TUP). This mRNA is 402 bp in length, is expressed during embryo formation, and reaches its highest accumulation in the flowers and roots of adult carrot plants. The mRNA is barely detectable in leaves. The accumulation of the TUP mRNA in seedlings is increased by auxin and by abscisic acid. The open reading frame encodes a tiny, uniquely structured protein of 6100 Daltons which has a pI of 5.3. Algorithms predicting protein structure suggest ...


Genetic Analysis Of Quantitative Trait Loci With Inbred And Hybrid Progeny Of Maize , David Frederick Austin Jan 1997

Genetic Analysis Of Quantitative Trait Loci With Inbred And Hybrid Progeny Of Maize , David Frederick Austin

Retrospective Theses and Dissertations

The first objective of this study was to compare quantitative trait loci (QTL) detection in two climatically diverse environments in a population of F6:7 lines of an elite maize (Zea mays L.) single-cross. The second objective was to detect QTL for general (GCA) and specific (SCA) combining ability effects in hybrid progeny of F2:3 and F6:8 lines from the same population. Evaluations of both inbred per se and hybrid progeny from the same population enabled comparisons between QTL controlling the two progeny types;The results from the F6:7 inbred progeny evaluations suggest that QTL detection can ...


Expression Of Genes Encoding Acetyl-Coa Carboxylase, Biotin Synthase, And Acetyl-Coa Generating Enzymes In Arabidopsis Thaliana , Jinshan Ke Jan 1997

Expression Of Genes Encoding Acetyl-Coa Carboxylase, Biotin Synthase, And Acetyl-Coa Generating Enzymes In Arabidopsis Thaliana , Jinshan Ke

Retrospective Theses and Dissertations

Acetyl-CoA carboxylase catalyzes the formation of malonyl-CoA from acetyl-CoA. The four genes encoding heteromeric acetyl-CoA carboxylase are coordinately expressed in leaves, flowers, and developing siliques and embryos. The highest expression occurs in tissues undergoing rapid growth and high oil deposition. The gene encoding the E1 [beta] subunit of chloroplastidic pyruvate dehydrogenase has an identical pattern, indicating it may provide acetyl-CoA for seeds. In contrast, the gene encoding acetyl-CoA synthetase has a different expression pattern and is expressed at low levels in seeds;The ACC1 genes encoding homomeric acetyl-CoA shows transient expression in a variety of cell types. The homomeric acetyl-CoA ...


The Role Of Domain E In The Activity Of Bacillus Macerans Cyclodextrin Glucanotransferase , Hai-Yin Chang Jan 1997

The Role Of Domain E In The Activity Of Bacillus Macerans Cyclodextrin Glucanotransferase , Hai-Yin Chang

Retrospective Theses and Dissertations

Cyclodextrin glucanotransferase (CGT) folds into five domains A, B, C, D and E. Domain E has the ability to bind starch and cyclodextrins (CDs) and is considered the starch-binding domain of CGT. The role of domain E in the catalysis of Bacillus macerans cyclodextrin glucanotransferase was investigated by constructing five CGT mutants. The truncated CGT (CGT[delta]E) mutant was constructed by deleting domain E, and the chimeric CGT (CGT-SBD) by replacing domain E with the starch-binding domain (SBD) of Aspergillus glucoamylase I. The modified CGT (CGT+6) was constructed by inserting a six-amino-acid pseudo linker between domains D and ...


Structure-Function Relationships In Porcine Fructose-1, 6-Bisphosphatase , Rulin Zhang Jan 1997

Structure-Function Relationships In Porcine Fructose-1, 6-Bisphosphatase , Rulin Zhang

Retrospective Theses and Dissertations

Fructose-1,6-bisphosphatase (FBPase) plays a crucial role in the regulation of gluconeogenesis. It is a homotetramer with a subunit molecular mass of 37 kDa. Each subunit has one substrate and three metal binding sites. Site-directed mutagenesis were carried out to replace amino acid residues which are thought to play important roles in structure integrity and functioning of the enzyme. Particular emphasis was placed on residues in the substrate and metal binding sites as well as the residues at the C1C2 (C3C4) interface. The mutant and wild-type FBPases were purified to homogeneity and characterized by initial-rate kinetics and circular dichroism spectrometry ...


Characterization Of The Expression Of Two Maize Root-Preferential Genes At The Protein Level , Lathika Pinto Moragoda Jan 1997

Characterization Of The Expression Of Two Maize Root-Preferential Genes At The Protein Level , Lathika Pinto Moragoda

Retrospective Theses and Dissertations

The zrp2 gene encodes an mRNA that accumulates preferentially in roots of maize. To study zrp2 gene expression at the protein level, an antibody was raised against an E. coli-produced ZRP2 protein. Western analyses using this antibody revealed an approximately 100 kDa protein in seedling roots that was not detected in seedling leaves. This size is about 30 kDa larger than the predicted molecular weight. Within seedling roots, low levels of ZRP2 protein were detected in the root tip and high levels were detected throughout the rest of the root. In mature maize plants, the ZRP2 protein was present at ...


Replication Of Barley Yellow Dwarf Luteovirus-Pav Rna , Mohan Bangalore Jan 1997

Replication Of Barley Yellow Dwarf Luteovirus-Pav Rna , Mohan Bangalore

Retrospective Theses and Dissertations

Barley yellow dwarf luteovirus (BYDV)-PAV serotype, an economically important virus of small grain cereals, has a positive-sense RNA genome encoding at least six open reading frames (ORFs). The goal of the research was to determine the genes and sequences involved in the viral replication and to design efficient antiviral strategies to BYDV-PAV. Genetically engineered resistance is essential for BYDV as the natural resistance is inadequate. Antiviral constructs such as sense RNA, antisense RNA and viral polymerase gene were tested for their ability to reduce virus titre in oat protoplasts as monitored by enzyme-linked immunosorbent assay. All antiviral constructs yielded ...


Protein Engineering Of The Ph Dependence And Substrate Specificity Of Glucoamylase From Aspergillus Awamori , Tsuei-Yun Fang Jan 1997

Protein Engineering Of The Ph Dependence And Substrate Specificity Of Glucoamylase From Aspergillus Awamori , Tsuei-Yun Fang

Retrospective Theses and Dissertations

Glucoamylase (EC 3.2.1.3) (GA), an enzyme that catalyzes the release of [beta]-D-glucose from the nonreducing ends of starch and related oligo- and polysaccharides, is widely used in industry to produce high-glucose syrups. Site-directed mutagenesis was used to construct mutations to obtain mutant enzymes with industrially desired alterations in pH dependence and substrate specificity;An increased pH optimum for GA would be industrially desirable so that it could be used in process conditions more similar to that of other enzymatic steps in starch processing. Five mutations were designed to remove or weaken the hydrogen bond between Ser411 ...


Use Of Pyrimidine Pathway To Produce Mutant Plants That Fail To Respond To Wound Induction , Lan Zhou Jan 1997

Use Of Pyrimidine Pathway To Produce Mutant Plants That Fail To Respond To Wound Induction , Lan Zhou

Retrospective Theses and Dissertations

To understand how proteinase inhibitor genes, as a part of plant defense system, are activated following wounding, we have developed a molecular genetic approach to directly select for mutants blocked in wound response in Arabidopsis thaliana. The wound-inducible promoter from the potato Proteinase Inhibitor 11 gene (pin2) was linked to a bacterial negative marker gene codA encoding for cytosine deaminase and transformed into Arabidopsis thaliana. The cytosine deaminase activity was detected in the leaves of the transgenic plants induced by sucrose, ABA, methyl jasmonate and mechanical wounding. Methyl jasmonate was the best for the pin2 induction in the seedlings among ...


Structure And Function Of Escherichia Coli Valine Transfer Rna In Aminoacylation And Ternary Complex Formation , Jack Chia-Hsiang Liu Jan 1997

Structure And Function Of Escherichia Coli Valine Transfer Rna In Aminoacylation And Ternary Complex Formation , Jack Chia-Hsiang Liu

Retrospective Theses and Dissertations

The relationship of E. coli tRNA Val structure to its function in the aminoacylation reaction and the later steps of polypeptide synthesis was investigated. Steady-state kinetic studies of the aminoacylation of invitro transcribed tRNA Val variants have shown that nucleotides, A35, C36, A73, and G20, are important for the specific recognition of E. coli tRNA Val by valyl-tRNA synthetase (ValRS). Identity swap experiments, testing the efficiency of this "recognition nucleotide set" in converting yeast tRNA Phe and E. coli tRNA Phe into caline acceptors, confirm the importance of the recognition nucleotide set. In addition, a minor recognition nucleotide, G45, was ...