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Articles 1 - 17 of 17

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

Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos Jan 1990

Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos

Retrospective Theses and Dissertations

Computer models have been widely used to simulate pressure and flow propagation in the arterial system. While experimentation involving the human arterial system is difficult and impractical, computer models offer an attractive alternative for the study of arterial hemodynamics. The purpose of the present study was to develop a computer model of the whole systemic circulation and to use this model to study pressure and flow propagation under normal flow conditions, as well as under conditions of arterial disease;The mathematical model used to describe flow in an arterial segment was based on the one-dimensional continuity and momentum equations. The ...


Excited State Structure, Energy And Electron Transfer Dynamics Of Photosynthetic Reaction Centers: A Hole Burning Study , Deming Tang Jan 1990

Excited State Structure, Energy And Electron Transfer Dynamics Of Photosynthetic Reaction Centers: A Hole Burning Study , Deming Tang

Retrospective Theses and Dissertations

The excited state structure, early time energy and electron transfer dynamics for bacterial photosynthetic reaction centers of Rhodoseudomonas viridis, Rhodobacter sphaeroides and green plant photosynthetic reaction center of Photosystem II (PS II) have been determined by hole burning spectroscopy. Transient hole burned spectra of the bacterial reaction centers reveal a special pair Franck-Condon marker mode progression with a superimposed zero phonon hole. Such progression is found to be absent in green plant Photosystem II which raises the question of structural similarities between the PS II and bacterial reaction centers. The excited state decay times are obtained for all systems and ...


The 5Å Resolution Crystal Structure Of Adenylosuccinate Synthetase From Escherichia Coli , Michael Alan Serra Jan 1990

The 5Å Resolution Crystal Structure Of Adenylosuccinate Synthetase From Escherichia Coli , Michael Alan Serra

Retrospective Theses and Dissertations

The technique of X-ray crystallography has been employed to determine the structure of adenylosuccinate synthetase from Escherichia coli to a resolution of 5A. Three crystalline forms of the enzyme have been obtained. The structure determination of the P21 crystal form was pursued due to its excellent diffraction properties and its rapid and reproducible growth. The P21 form crystallizes as a dimer. Unit cell parameters are as follows: a = 73.31(9)A, b = 72.23(7)A, c = 82.87(9)A, [beta] = 108.59°(6). The unit cell volume is 416,700(1,200)A[superscript]3.;A suitable ...


Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson Jan 1990

Genetic And Molecular Analyses Of Suppressor Of Forked In Drosophila Melanogaster , Cynthia Lynn Fitch-Steenson

Retrospective Theses and Dissertations

Mutations at the suppressor of forked, su(f), locus are trans-acting, allele specific suppressors and enhancers of mutations at certain other loci. Su(f) is a trans-acting regulator whose normal product is necessary for proper transcription of these genes. The su(f) product regulates the transcription of transposable elements located within these genes. Our investigation includes a genetic analysis in which a number of new su(f) alleles were isolated, a development analysis in which the effects of new alleles and allelic combinations were characterized, and a molecular analysis in which a cloned genomic DNA fragment containing su(f) was ...


The Crystal Structure Of Adenylosuccinate Synthetase From Escherichia Coli , Kyung Hyun Kim Jan 1990

The Crystal Structure Of Adenylosuccinate Synthetase From Escherichia Coli , Kyung Hyun Kim

Retrospective Theses and Dissertations

The crystal structure of adenylosuccinate synthetase from Eschericha coli has been pursued to a resolution of 3.7 A. Using isomorphous and anomalous (SIRAS) phases from a HgI[subscript]4[superscript]2- derivative, electron density maps were generated that clearly revealed the envelope of the enzyme dimer and the two-fold molecular symmetry of the dimer;Since the enzyme is active as a dimer consisting of two identical monomers, the method of density averaging (Bricogne, 1976) was employed to improve the electron density map based on SIRAS phases. The non-crystallographic two-fold operator, which relates two monomers, was refined against an SIRAS ...


Molecular Characterization Of The Yeast Gene Hsp60 , Donald Stevenson Reading Jan 1990

Molecular Characterization Of The Yeast Gene Hsp60 , Donald Stevenson Reading

Retrospective Theses and Dissertations

In all organisms studied, heat shock or other stressful stimuli lead to profound changes in gene expression. During heat shock, a small group of evolutionarily conserved proteins, termed heat shock proteins (hsps), are synthesized in abunDance; Several hsps are known to have vital cellular function even at normal temperature. These hsps have the capacity to bind polypeptide chains and have a probable role in the folding, translocation, and assembly pathways of many proteins. One such protein, hsp60, is located within mitochondria, is highly conserved in evolution, and based on immunological and physical characterization, is a member of a family of ...


Purification And Partial Characterization Of Arg-Specific Adp-Ribosyltransferase From Skeletal Muscle Microsomal Membranes , Jon Eric Peterson Jan 1990

Purification And Partial Characterization Of Arg-Specific Adp-Ribosyltransferase From Skeletal Muscle Microsomal Membranes , Jon Eric Peterson

Retrospective Theses and Dissertations

Integral membrane-associated arginine specific mono-ADP-ribosyltransferase was purified from rabbit skeletal muscle microsomes. The ADP-ribosyltransferase was solubilized from the 100,000 x g pellet with 0.3% sodium deoxycholate and purified to ≥95% homogeneity by successive DE-52, concanavalin A agarose, 3-aminobenzamide agarose and size exclusion chromatography steps in the presence of detergents. Two molecular weight forms of the enzyme were isolated and partially characterized. The apparent Mr of the [alpha]-form of the enzyme purified to ≥95 homogeneity was about 39,000 ± 500 as estimated by silver-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis. The Mr of the [beta] form purified to ...


Studies Of A Secreted, Superinducible Protein, Sip 24 , Thomas Richard Davis Jan 1990

Studies Of A Secreted, Superinducible Protein, Sip 24 , Thomas Richard Davis

Retrospective Theses and Dissertations

A series of studies were conducted to purify, characterize, sequence, and evaluate the mechanism of expression of a secreted, superinducible protein, SIP 24. It has been found that the potent tumor promoter, 12-o-tetradecanoyl-13-acetate (TPA) in combination with the protein synthesis inhibitor, cycloheximide (CHX), can synergistically increase SIP 24 expression. The in vivo activator of protein kinase C (PKC), diacylglycerol, also increased SIP 24 expression. Further evidence that PKC is involved in regulating SIP 24 expression, was found when an inhibitor of PKC, H7, was added to cells stimulated by TPA and bFGF, and SIP 24 levels were reduced. Studies, in ...


Cell-Wall Components And Lignin Biosynthesis In Forages , James Enderby Bidlack Jan 1990

Cell-Wall Components And Lignin Biosynthesis In Forages , James Enderby Bidlack

Retrospective Theses and Dissertations

Lignin is the major cell-wall (CW) component that lowers forage digestibility. Negative relationships between lignin and forage quality are caused by interactions and variability of lignin with other CW components. This study was conducted to better understand how lignin content, concentration, deposition, and change in concentration vary with other CW components in maturing stems and to provide preliminary information about phenylpropanoid metabolism in relation to lignification;Regrowth from basal stem tissue was sampled weekly or biweekly from greenhouse-grown forage grass and legume species. Samples were collected for a period of about 8 weeks and analyzed for fiber concentration and content ...


Specificity Of Cholera Toxin And Mono(Adp-Ribosyl)Transferase Activity In Cultured Myoblasts , Shanta Virabhai Kharadia Jan 1990

Specificity Of Cholera Toxin And Mono(Adp-Ribosyl)Transferase Activity In Cultured Myoblasts , Shanta Virabhai Kharadia

Retrospective Theses and Dissertations

The relationship between ADP-ribosylation and phosphorylation using a model substrate, the specificity requirements for cholera toxin-catalyzed ADP-ribosylation using peptide substrates, and the role of ADP-ribosylation reactions in skeletal muscle were studied;Cholera toxin preferentially ADP-ribosylates the first arginyl residue of kemptide (Leu-Arg-Arg-Ala-Ser-Leu-Gly) and some ADP-ribosylation was observed on the second arginyl residue. A di(ADP-ribosyl)ated product was also formed. Phosphorylated seryl residue of kemptide decreased the extent of ADP-ribosylation of the arginyl residues by cholera toxin and mono(ADP-ribosyl)ated kemptide was a poor substrate for the cAMP-dependent protein kinase. Di(ADP-ribosyl)ated kemptide was not phosphorylated at all ...


Regulation Of Protein Expression By Transforming Growth Factor Beta And Other Growth Modulators , Frederic William Thalacker Jan 1990

Regulation Of Protein Expression By Transforming Growth Factor Beta And Other Growth Modulators , Frederic William Thalacker

Retrospective Theses and Dissertations

The main goal of this project was to understand the signal transduction pathways through which growth modulators such as TGF-[beta], PMA and retinoic acid mediate protein expression and DNA synthesis. Transforming growth factor [beta] (TGF-[beta]) induces synthesis and secretion of a 48,000 M r protein that we have found to be type I plasminogen activator inhibitor (PAI-1). TGF-[beta] induces PAI-1 in every cell line that we have studied including near term mink lung epithelial CCL64 cells, mouse embryo fibroblast AKR-2B 84A cells, African green monkey kidney epithelial BSC-1 cells, and normal rat kidney fibroblast NRK 49F ...


A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng Jan 1990

A Restriction Fragment Length Polymorphism Map Of Cochliobolus Heterostrophus , Tzy-Hwa Tzeng

Retrospective Theses and Dissertations

An RFLP map was constructed for Cochliobolus heterostrophus, the causal agent of southern corn leaf blight, to facilitate the cloning of pathogenicity genes. A total of 128 RFLP and 4 phenotypic markers were analyzed. Of these, 126 were linked to other markers and delimited 944 cM, or, at a maximum, 58% of the total map length. Several RFLPs were found tightly linked to Tox1, a pathogenicity gene. A previously hypothesized translocation tightly linked to Tox1 was also detected;The numbers and sizes of the chromosomes of the two strains crossed to make the RFLP map were investigated using pulsed field ...


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 ...


Isolation Of A Chicken Cardiac Muscle Titin Cdna Probe , Greg Robert Sater Jan 1990

Isolation Of A Chicken Cardiac Muscle Titin Cdna Probe , Greg Robert Sater

Retrospective Theses and Dissertations

The objective of this project was to construct and identify a cDNA probe for the striated muscle protein titin. RNA was isolated from skeletal and cardiac muscle of 16 day chicken embryos using a guanidinium isothiocyanate procedure. The RNA thus isolated was both intact (as shown by agarose gel electrophoresis) and transcribable in vitro; additionally, it was possible to obtain very large RNA molecules in this manner. cDNA was then constructed utilizing random oligodeoxynucleotides for priming of the first strand synthesis reaction, instead of the more common oligo-dT priming. Random priming was also utilized for second strand synthesis. As with ...


Analysis And Characterization Of The Major Histocompatibility Complex Of Domestic Animals , Yuanxin Xu Jan 1990

Analysis And Characterization Of The Major Histocompatibility Complex Of Domestic Animals , Yuanxin Xu

Retrospective Theses and Dissertations

The major histocompatibility complex (MHC) is a family of genes coding for molecules which play important roles in the immune response as well as many other cellular processes of a vertebrate organism. The understanding of the immune system of some of the domestic animals will have both practical value and theoretical significance. The purpose of this work was to study the MHC of the chicken (B) and the swine (SLA). First, in order to study the MHC class II gene structure of the chicken, a genomic library was constructed from an inbred chicken line G-B2 (MHC haplotype B[superscript]6 ...


Interaction Of Metal, Amp, And Fructose 2,6-Bisphosphate With Rabbit Liver Fructose-1,6-Bisphosphatase , Feng Liu Jan 1990

Interaction Of Metal, Amp, And Fructose 2,6-Bisphosphate With Rabbit Liver Fructose-1,6-Bisphosphatase , Feng Liu

Retrospective Theses and Dissertations

The effect of thiol group modification of rabbit liver fructose-1,6-bisphosphatase by N-ethylmaleimide (NEM) was investigated. The results of these studies suggest that the substrate, fructose 1,6-bisphosphate (Fru-1,6-P2), is almost as effective as the inhibitor, fructose 2,6-bisphosphate (Fru-2,6-P2), in preventing loss of Fru-2,6-P2 inhibition when the enzyme is modified by NEM. What differences exist between the two ligands in their ability to protect against loss of Fru-2,6-P2 inhibition seem to be quantitative rather than qualitative. Our experimental results suggest that Fru-2,6-P2 binds to the enzyme at its active site;The binding site(s ...


Active Site Studies And Mechanism Of Action Of Leuconostoc Mesenteroides B-512fm Dextransucrase , Daotian Fu Jan 1990

Active Site Studies And Mechanism Of Action Of Leuconostoc Mesenteroides B-512fm Dextransucrase , Daotian Fu

Retrospective Theses and Dissertations

Leuconostoc mesenteroides NRRL B-512FM dextransucrase was treated extensively with Sigma crude dextranase, followed by column chromatography on Bio-Gel A-5m. The purified dextransucrase has a specific activity of 84 IU/mg, and was shown by SDS-PAGE to have a single protein of 158 kDa with dextransucrase activity. The procedure gave a 100-fold purification with 42% yield, and was used to produce purified enzyme for sequencing;The active site of dextransucrase was studied by chemical modification with diethyl pyrocarbonate and photo-dye-oxidation. Kinetic analysis of the inactivation data showed that two histidines are essential for the dextransucrase activity. We proposed that the two ...