UNT Libraries - 34 Matching Results

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Tobacco Phospholipase D β1: Molecular Cloning and Biochemical Characterization

Description: Transgenic tobacco plants were developed containing a partial PLD clone in antisense orientation. The PLD isoform targeted by the insertion was identified. A PLD clone was isolated from a cDNA library using the partial PLD as a probe: Nt10B1 shares 92% identity with PLDβ1 from tomato but lacks the C2 domain. PCR analysis confirmed insertion of the antisense fragment into the plants: three introns distinguished the endogenous gene from the transgene. PLD activity was assayed in leaf homogenates … more
Date: December 2002
Creator: Hodson, Jane E.
Item Type: Refine your search to only Thesis or Dissertation
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FLP-mediated conditional loss of an essential gene to facilitate complementation assays

Description: Commonly, when it is desirable to replace an essential gene with an allelic series of mutated genes, or genes with altered expression patterns, the complementing constructs are introduced into heterozygous plants, followed by the selection of homozygous null segregants. To overcome this laborious and time-consuming step, the newly developed two-component system utilizes a site-specific recombinase to excise a wild-type copy of the gene of interest from transformed tissues. In the first componen… more
Date: December 2007
Creator: Ganesan, Savita
Item Type: Refine your search to only Thesis or Dissertation
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Function of the ENOD8 gene in nodules of Medicago truncatula.

Description: To elaborate on the function(s) of the ENOD8 gene in the nodules of M. truncatula, several different experimental approaches were used. A census of the ENOD8 genes was first completed indicating that only ENOD8.1 (nt10554-12564 of GenBank AF463407) is highly expressed in nodule tissues. A maltose binding protein-ENOD8 fusion protein was made with an E. coli recombinant system. A variety of biochemical assays were undertaken with the MBP-ENOD8 recombinant protein expressed in E. coli, which did … more
Date: December 2006
Creator: Coque, Laurent
Item Type: Refine your search to only Thesis or Dissertation
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Functional Characterization of Plant Fatty Acid Amide Hydrolases

Description: Fatty acid amide hydrolase (FAAH) terminates the endocannabinoid signaling pathway that regulates numerous neurobehavioral processes in animals by hydrolyzing a class of lipid mediators, N-acylethanolamines (NAEs). Recent identification of an Arabidopsis FAAH homologue (AtFAAH) and several studies, especially those using AtFAAH overexpressing and knock-out lines suggest that a FAAH-mediated pathway exists in plants for the metabolism of endogenous NAEs. Here, I provide evidence to support this … more
Date: December 2010
Creator: Kim, Sang-Chul
Item Type: Refine your search to only Thesis or Dissertation
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The Relationship of Force on Myosin Subfragment 2 Region to the Coiled-Coiled Region of the Myosin Dimer

Description: The stability of myosin subfragment 2 was analyzed using gravitational force spectroscopy. The region was found to destabilize under physiological force loads, indicating the possibility that subfragment 2 may uncoil to facilitate actin binding during muscle contraction. As a control, synthetic cofilaments were produced to discover if the observations in the single molecule assay were due to the lack of the stability provided by the thick filament. Statistically, there was no difference betwee… more
Date: December 2011
Creator: Hall, Nakiuda M.
Item Type: Refine your search to only Thesis or Dissertation
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Dependence of the Kinetic Mechanism of Adenosine 3',5'-Monophosphate Dependent Protein Kinase Catalytic Subunit in the Direction of Magnesium Adenosine 5'-Diphosphate Phosphorylation on pH and the Concentration of Free Magnesium Ions

Description: To define the overall kinetic and chemical mechanism of adenosine 3',5'-monophosphate dependent protein kinase catalytic subunit, the mechanism in the direction of MgADP phosphorylation was determined, using studies of initial velocity in the absence and presence of dead-end inhibitors. The kinetic mechanism was determined as a function of uncomplexed Mg^2+ (Mg_f) at pH 7.2 and as a function of pH at low (0.5 mM) Mg_f. At pH 7.2 data are consistent with a random kinetic mechanism in the directi… more
Date: December 1992
Creator: Qamar, Raheel
Item Type: Refine your search to only Thesis or Dissertation
open access

N-Acylethanolamines and Plant Phospholipase D

Description: Recently, three distinct isoforms of phospholipase D (PLD) were identified in Arabidopsis thaliana. PLD α represents the well-known form found in plants, while PLD β and γ have been only recently discovered (Pappan et al., 1997b; Qin et al., 1997). These isoforms differ in substrate selectivity and cofactors required for activity. Here, I report that PLD β and γ isoforms were active toward N-acylphosphatidylethanolamine (NAPE), but PLD α was not. The ability of PLD β and γ to hydrolyze NAPE mar… more
Date: December 1998
Creator: Brown, Shea Austin
Item Type: Refine your search to only Thesis or Dissertation
open access

Cottonseed Microsomal N-Acylphosphatidylethanolamine Synthase: Identification, Purification and Biochemical Characterization of a Unique Acyltransferase

Description: N-Acylphosphatidylethanoiamine (NAPE) is synthesized in the microsomes of cotton seedlings by a mechanism that is possibly unique to plants, the ATP-, Ca2+-, and CoA-independent acylation ofphosphatidylethanolamine (PE) with unesterified free fatty acids (FFAs), catalyzed by NAPE synthase. A photoreactive free fatty acid analogue, 12-[(4- azidosalicyl)amino]dodecanoic acid (ASD), and its 125I-labeled derivative acted as substrates for the NAPE synthase enzyme.
Date: December 1998
Creator: McAndrew, Rosemary S. (Rosemary Smith)
Item Type: Refine your search to only Thesis or Dissertation
open access

Fumarate Activation and Kinetic Solvent Isotope Effects as Probes of the NAD-Malic Enzyme Reaction

Description: The kinetic mechanism of activation of the NAD-malic enzyme by fumarate and the transition state structure for the oxidation malate for the NAD-malic enzyme reaction have been studied. Fumarate exerts its activating effect by decreasing the off-rate for malate from the E:Mg:malate and E:Mg:NAD:malate complexes. The activation by fumarate results in a decrease in K_imalate and an increase in V/K_malate by about 2-fold, while the maximum velocity remains constant. A discrimination exists between … more
Date: December 1992
Creator: Lai, Chung-Jeng
Item Type: Refine your search to only Thesis or Dissertation
open access

Kinetic and Chemical Mechanism of Pyrophosphate-Dependent Phosphofructokinase

Description: Data obtained from isotope exchange at equilibrium, exchange of inorganic phosphate against forward reaction flux, and positional isotope exchange of 18O from the (βγ-bridge position of pyrophosphate to a (β-nonbridge position all indicate that the pyrophosphate-dependent phosphofructokinase from Propionibacterium freudenreichii has a rapid equilibrium random kinetic mechanism. All exchange reactions are strongly inhibited at high concentrations of the fructose 6-phosphate/Pi and MgPPi/Pi subst… more
Date: December 1988
Creator: Cho, Yong Kweon
Item Type: Refine your search to only Thesis or Dissertation
open access

Studies of the Mechanism of Plasma Cholesterol Esterification in Aged Rats

Description: The study was performed to determine factors influencing the esteriflcation of plasma cholesterol in young and aged rats. The distribution of LCAT activity was determined following gel nitration chromatography and ultracentrifugation of whole plasma respectively. When rat plasma was fractionated on a Bio-Gel A-5 Mcolumn, LCAT activity was found to be associated with the HDL fraction. A similar result was observed upon 24 hr density gradient ultracentrifugation of the plasma. However, following … more
Date: December 1989
Creator: Lee, Sun Min
Item Type: Refine your search to only Thesis or Dissertation
open access

Purification of HMG-CoA Reductase and Regulation by Protein-Lipid Interactions

Description: The enzyme 3-Hydroxy-3- Methylglutaryl Coenzyme A Reductase catalyzes the rate limiting step of hepatic cholesterol biosynthesis and is unique among the enzymes in the early part of the pathway in that it is membrane bound. This gives rise to potential regulation of the enzyme through interactions with the endoplasmic reticulum membrane. A purification procedure has been developed which consistently produces enzyme of high specific activity. In order to fully characterize the interactions betwe… more
Date: December 1982
Creator: Brent, Lynn G. (Lynn Gran)
Item Type: Refine your search to only Thesis or Dissertation
open access

Analysis of Human Transfer RNA Gene Heteroclusters

Description: Two phage lambda clones encompassing human tRNA genes have been isolated from a human gene library harbored in bacteriophage lambda Charon-UA. One of the clones (designated as hLeuU) containing a 20-kb human DNA fragment was isolated and found to contain a cluster of four tRNA genes. An 8.2-kb Hindlll fragment encompassing the four tRNA genes was isolated from the 20-kb fragment and subcloned into pBR322 for restriction mapping and DNA sequence analysis. The four tRNA genes are arranged as two… more
Date: December 1986
Creator: Chang, Yung-Nien
Item Type: Refine your search to only Thesis or Dissertation
open access

Metabolism of Diadenosine-5ʹ,5ʹʹʹ-P¹,P⁴-tetraphosphate (Ap₄A) in Cultured Mammalian Cells

Description: Methodology was developed which allowed the rapid and routine quantitation of subpicomole quantities of diadenosine-5ʹ,5ʹʹʹ-P¹,P⁴-tetraphosphate (Ap₄A) in cultured mammalian cells. This methodology includes the rapid extraction of cellular nucleotides in cold alkali, resolution of Ap₄A from the bulk of cellular materials on a highly specific boronate affinity resin, and quantitation of the dinucleotide in a coupled bioluminescence assay utilizing venom phosphodiesterase and firefly luciferase. … more
Date: December 1984
Creator: Baker, Jeffrey C. (Jeffrey Clayton)
Item Type: Refine your search to only Thesis or Dissertation
open access

Poly(ADP-ribose) Synthesis as a Function of Growth and DNA Fragmentation

Description: This work examines the synthesis of poly(ADP-ribose) in normal and SV40-transformed monolayer cultures of 3T3 cells as a function of growth and DNA fragmentation. A review of the relevant literature is given in the introduction of this work. Poly(ADP-ribose) synthesis has been implicated in transcription, replication, repair, differentiation and regulation of cell growth. The results of this study suggest that poly(ADP-ribose) synthesis is involved in some aspect of cell-growth control and DNA … more
Date: December 1981
Creator: Levi, Viktorya
Item Type: Refine your search to only Thesis or Dissertation
open access

Modification of Cardiac Membrane Gsα by an Endogenous Arginine-Specific Mono-Adp-Ribosyltransferase

Description: The mechanism by which nicotinamide adenine dinucleotide (NAD) stimulates the activity of adenylate cyclase (AC) in canine plasma membrane has been studied. Using [3 2P]-NAD, the activation by NAD was correlated with the radiolabeling of the stimulatory guanosine triphosphate (GTP) binding protein Gsa. Further characterization demonstrated that the modification occurred only in the presence of G-protein activators and that arginine residue(s) were modified by ADP-ribose by the action of a mono-… more
Date: December 1993
Creator: Coyle, Donna L. (Donna Lynn)
Item Type: Refine your search to only Thesis or Dissertation
open access

Mechanism of Activation by Autophosphorylation of an S6/H4 Kinase Isolated From Human Placenta

Description: A novel molecular mechanism of autophosphorylation-dependent activation of the ser/thr S6/H4 kinase isolated from human placenta is described. Phosphopeptide mapping of the enzyme was used to determine the rate and extent of site-specific autophosphorylation. These data were correlated to phosphotransferase activity of the protein kinase. The results indicated that a sequential phosphorylation of two sites in the catalytic domain is required for maximum activation. Kinetic analysis determined t… more
Date: December 1994
Creator: Benner, Gretchen E. (Gretchen Evonne)
Item Type: Refine your search to only Thesis or Dissertation
open access

Molecular and Functional Characterization of Medicago Truncatula Npf17 Gene

Description: Legumes are unique among plants for their ability to fix atmospheric nitrogen with the help of soil bacteria rhizobia. Medicago truncatula is used as a model legume to study different aspects of symbiotic nitrogen fixation. M. truncatula, in association with its symbiotic partner Sinorhizobium meliloti, fix atmospheric nitrogen into ammonia, which the plant uses for amino acid biosynthesis and the bacteria get reduced photosynthate in return. M. truncatula NPF1.7 previously called MtNIP/LATD is… more
Date: December 2013
Creator: Salehin, Mohammad
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open access

Functional Characterization of Mtnip/latd’s Biochemical and Biological Function

Description: Symbiotic nitrogen fixation occurs in plants harboring nitrogen-fixing bacteria within the plant tissue. The most widely studied association is between the legumes and rhizobia. In this relationship the plant (legumes) provides the bacteria (rhizobia) with reduced carbon derived from photosynthesis in exchange for reduced atmospheric nitrogen. This allows the plant to survive in soil, which is low in available of nitrogen. Rhizobia infect and enter plant root and reside in organs known as nodul… more
Date: December 2013
Creator: Bagchi, Rammyani
Item Type: Refine your search to only Thesis or Dissertation
open access

Protein Kinase C Activation in Hyperglycemic Bovine Lens Epithelial Cells

Description: This study demonstrates the presence of protein kinase C activity in both cytosolic and membrane fractions of bovine lens epithelial cells in culture. Protein kinase C activity is similar in normal and hyperglycemic cells. Furthermore, the ability of the enzyme to translocate from the cytosol to the membrane following phorbol ester treatment is unimpeded by hyperglycemic conditions. Moreover, protein kinase C activation had no effect on myoinositol uptake either in normal cells or in cells expo… more
Date: December 1993
Creator: Fan, Wen-Lin
Item Type: Refine your search to only Thesis or Dissertation
open access

Chemical Mechanism of the Catalytic Subunit of Camp-Dependent Protein Kinase: Methods for Determining the Primary ¹⁸O Isotope Effects Using the Remote Label Technique

Description: A description of the nature of the transition state structure for phosphoryl transfer in the cAPK reaction requires a measurement of the primary 180 isotope effect at the serine hydroxyl acceptor. Since it is difficult to obtain primary 180 isotope effect directly, the 15N/1 4N ratio of the a-amine of the C-terminal glycine in the peptide Leu Arg-Lys-Ala-Ser-Leu-Gly (when serine is phosphorylated) was used to represent on the phosphorylation at serine. 15N Glycine, ' 4N-Glycine and 180 serine w… more
Date: December 1991
Creator: Chen, Gang, 1963-
Item Type: Refine your search to only Thesis or Dissertation
open access

Physical Mapping of Human Transfer RNA Gene Clusters

Description: Two plaque-pure phage lambda clones designated as λhtX-l and λhtX-2 that hybridized to unfractionated bovine liver tRNA were isolated from a human X chromosome-specific library. The λDNAs were characterized by restriction mapping and Southern blot hybridization techniques. The human DNA segment in λhtX-l contains five or more presumptive tRNA genes and at least one Alu family member. The 19-kilobase human DNA insert in λhtX-2 contains two or more presumptive tRNA genes and at least three Alu fa… more
Date: December 1989
Creator: Wang, Luping
Item Type: Refine your search to only Thesis or Dissertation
open access

Structural Analyses of a Human Valine Transfer RNA Gene and of a Transfer RNA Pseudogene Cluster

Description: Two different cloned human DNA segments encompassing transfer RNA gene and pseudogene clusters have been isolated from a human gene library harbored in bacteriophage lambda Charon 4-A. One clone (designated as λhVal7) encompassing a 20.5-kilobase (Kb) human DNA insert was found to contain a valine transfer RNA_AAC gene and several Alu-like elements by Southern blot hybridization analysis and DNA sequencing with the dideoxyribonucleotide chain-termination method in the bacteriophage M13mp19 vect… more
Date: December 1987
Creator: Lee, Mike Ming-Jen
Item Type: Refine your search to only Thesis or Dissertation
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Synthesis and Kinetic Mechanism Study of Phosphonopeptide as a Dead-End Inhibitor of cAMP-Dependent Protein Kinase

Description: DL-2-Amino-4-phosphonobutyric acid, an isostere of phosphoserine, was incorporated into the heptapeptide sequence, Leu-Arg-Arg-Ala-(DL-2-amino-4-phosphonobutyric acid)-Leu-Gly, for kinetic mechanistic studies of the cAMP-dependent protein kinase. To block the phosphono hydroxyl groups, methyl, ethyl and 4nitrobenzyl esters were studied as possible protecting groups. The phosphono diethyl ester of the N-Fmoc-protected amino acid was utilized in the synthesis of the heptapeptide. Two configuratio… more
Date: December 1991
Creator: Yang, Chunhua
Item Type: Refine your search to only Thesis or Dissertation
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