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Articles 1 - 17 of 17

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

Molecular Mechanisms Controlling Bovine Lymphocyte Homing , Brad Thomas Bosworth Jan 1991

Molecular Mechanisms Controlling Bovine Lymphocyte Homing , Brad Thomas Bosworth

Retrospective Theses and Dissertations

The cDNA clones encoding for the bovine glycoproteins CD44 and LECAM-1 (lectin cell adhesion molecule-1) were isolated and sequenced. The predicted amino acid sequences of bovine CD44 and LECAM-1 had high identities with those of human and murine CD44 and LECAM-1. The high identities of the predicted amino acid sequences of these glycoproteins in the bovine, human and mouse suggest they may have similar functions in all three species. While the overall amino acid identities were high, bovine CD44 had an area of low identity with human and murine CD44 in the extracellular domain and the cytoplasmic tail of bovine ...


Study Of Secondary Structure Of Protein Sequences By Linear Algebra , Wei-Hua Hsieh Jan 1991

Study Of Secondary Structure Of Protein Sequences By Linear Algebra , Wei-Hua Hsieh

Retrospective Theses and Dissertations

Using encoding schemes, we study the relation between amino acids and protein structure in linear spaces;Local protein-structure prediction schemes use the amino acid sequences in a short subchain of a protein to predict the protein secondary structure of the middle residue of the chain;Two relatively reliable, objective and quantitative local prediction schemes are Robson et al.'s information theory method and and Qian & Sejnowski's neural network models. The latter achieved 64% accuracy for three-state predictions in 1989, the best prediction performance yet recorded;We assign to the 20 amino acids, through a one-to-one correspondence, the 20 columns (unit vectors) of the 20 x 20 identity matrix. Then any chain of k amino acids may be represented as a ...


Identification Of Intermediate Filaments And Their Proteins In Mature Mammalian Striated Muscle , Masako Maria Bilak Jan 1991

Identification Of Intermediate Filaments And Their Proteins In Mature Mammalian Striated Muscle , Masako Maria Bilak

Retrospective Theses and Dissertations

The major purposes of this study were to: (1) clearly identify intermediate filaments (IFs) and elucidate their structural arrangement at the myofibrillar Z-lines in non-diseased, mature mammalian striated muscle cells, and (2) determine the localization of constituent proteins of the IFs by immunogold localization. IFs running transversely to the long axis of the cell and connecting Z-lines of adjacent myofibrils were identified by high resolution transmission electron microscopy (TEM) of plastic-embedded porcine semitendinosus muscle, especially in areas of cells where myofibrils were less tightly packed. When the plane of section included the periphery of myofibrils at their Z-lines, examination indicated ...


Selected Properties Of The Cytoskeletal Protein Synemin And Its Interactions With Proteins At The Muscle Z-Line , Stephan Roman Bilak Jan 1991

Selected Properties Of The Cytoskeletal Protein Synemin And Its Interactions With Proteins At The Muscle Z-Line , Stephan Roman Bilak

Retrospective Theses and Dissertations

The primary purposes of this study were to: (1) examine selected properties of the intermediate filament-associated protein (IFAP), synemin, (2) identify synemin (or a synemin homolog) in adult mammalian muscle, and (3) examine synemin's ability to interact with proteins located at the myofibrillar Z-line. An integrated biochemical, immunological, and ultrastructural approach was used;Synemin (230 kD) was solubilized from an actomyosin-extracted avian smooth muscle residue and purified by chromatography on two hydroxyapatite columns and one DEAE-Sephacel column in the presence of 6 M urea. Renatured, soluble synemin was obtained by removal of the urea by dialysis against 10 mM ...


Effects Of Oxysterols On Acyl-Coa: Cholesterol Acyltranferase , Meiling Shih Jan 1991

Effects Of Oxysterols On Acyl-Coa: Cholesterol Acyltranferase , Meiling Shih

Retrospective Theses and Dissertations

Two oxysterols, 20(R and S)-20,25-dihydroperoxy-5-cholesten-3[beta]-ol (HPs) isolated from the mixture of cholesterol autoxidation products have been found to reduce effectively cholesteryl ester accumulation in mouse peritoneal macrophages. The effect of HPs was associated with inhibition of cholesterol esterification by suppressing acyl-CoA:cholesterol acyltransferase activity, and by interruption of acetylated low-density-lipoprotein metabolism. The mechanism by which HPs inhibit ACAT activity is investigated in detail in the present study. With reconstituted liposomes, I demonstrated that an increase in cholesterol concentration did not prevent the inhibitory effect of HPs. On the other hand, inactivated ACAT activity was partially ...


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 ...


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 ...


Avena Phytochrome Mrna: In Vivo Localization, Degradation Products, And Half-Life , Kevin Andrew Seeley Jan 1991

Avena Phytochrome Mrna: In Vivo Localization, Degradation Products, And Half-Life , Kevin Andrew Seeley

Retrospective Theses and Dissertations

The purpose of this research is to determine the role that post-transcriptional processes play in the regulation of phytochrome (phy) steady-state messenger RNA (mRNA) levels. The control of etiolated phytochrome (phyA) and chlorophyll a/b binding protein (cab) gene transcription and steady-state mRNA levels are known to be regulated by the phyA signal transduction pathway. I performed a number of control experiments that indicate the degradation products detected in northern analysis of phyA mRNA were produced in vivo and were not an artifact of RNA isolation techniques. I have also shown that infrared (IR) irradiation has no appreciable effect on ...


Effect Of 1,10-Phenanthroline On Dna Binding Of 1,25-Dihydroxyvitamin D Receptors And Characterization And Regulation Of Retinoic Acid Receptors In Rat Osteosarcoma Cells , Kevin Brady Atkins Jan 1991

Effect Of 1,10-Phenanthroline On Dna Binding Of 1,25-Dihydroxyvitamin D Receptors And Characterization And Regulation Of Retinoic Acid Receptors In Rat Osteosarcoma Cells , Kevin Brady Atkins

Retrospective Theses and Dissertations

The effect of the chelator 1,10-phenanthroline on the DNA-binding of 1,25-dihydroxyvitamin D receptor was demonstrated. Increasing concentrations of the chelator, up to 3 mM, decreased receptor binding to DNA-cellulose. This effect was specific for the chelating function because the nonchelating analog, 1,7-phenanthroline, did not inhibit DNA-cellulose binding of the receptor. The cations, Cd[superscript]2+ and Zn[superscript]2+, were able to block chelator-mediated inhibition. These cations were unable to reverse the inhibition unless 1,10-phenanthroline was removed by dialysis;The rat osteosarcoma 17/2.8 cells were shown to express both the cellular retinoic acid binding ...


Characterization Of The Mitogen Regulated Protein Receptor , Joseph T. Nelson Jan 1991

Characterization Of The Mitogen Regulated Protein Receptor , Joseph T. Nelson

Retrospective Theses and Dissertations

Mitogen regulated protein (MRP) is a glycoprotein synthesized in murine placenta and secreted into the maternal bloodstream during gestation. The temporal profile of MRP concentration in the plasma during gestation, its synthesis in an organ known to secrete other lactogenic hormones, and its homology to prolactin suggest an hormonal role;A requisite characteristic of a polypeptide hormone is to have a receptor on the plasma membrane of another tissue separate from its site of synthesis. The receptor then mediates the functional effects by binding the hormone. I discovered and characterized a receptor for MRP from murine uterine membrane preparations. The ...


In Vitro Desmin Assembly And In Vivo Changes In Developing Smooth Muscle , Rong-Ghi Robert Chou Jan 1991

In Vitro Desmin Assembly And In Vivo Changes In Developing Smooth Muscle , Rong-Ghi Robert Chou

Retrospective Theses and Dissertations

This dissertation is divided into two principal parts. The purpose of the first part was to investigate the effects of cations and temperature on the critical concentration of desmin required for filament assembly by using tow independent assays, namely, turbidity and centrifugation. Assembly was done in the presence of 2 mM Ca[superscript]2+, 2 mM Mg[superscript]2+ or 150 mM Na[superscript]+ at 2, 22 and 37°C. Similar values for critical concentration were obtained by both assays. As temperature increased, critical concentration decreased for each cation. Critical concentration was lowest in the presence of Ca[superscript]2 ...


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 ...


Changes In Gene Expression During Induction Of The Carbon Dioxide Concentrating Mechanism In Chlamydomonas Reinhardtii , Thomas Leslie Winder Jan 1991

Changes In Gene Expression During Induction Of The Carbon Dioxide Concentrating Mechanism In Chlamydomonas Reinhardtii , Thomas Leslie Winder

Retrospective Theses and Dissertations

The regulation of genes by CO[subscript]2 concentration in wild type and mutants of the unicellular green alga Chlamydomonas reinhardtii was studied. This and other algal species can photosynthesize efficiently under limiting concentrations of CO[subscript]2 due to the activities of a CO[subscript]2 concentrating mechanism and carbonic anhydrase. A cDNA copy of the gene that codes for a periplasmic carbonic anhydrase (perCA) was isolated and used to study regulation of perCA synthesis in a cell wall-deficient mutant (CW-15). Over-expression of perCA in CW-15, relative to wild type, was found at the levels of enzyme activity, protein ...


Purification And Properties Of The Malic Enzyme And The Malate Dehydrogenases From The Gill Tissue Of The Ribbed Mussel (Modiolus Demissus) , Mary Michael Brodey Jan 1991

Purification And Properties Of The Malic Enzyme And The Malate Dehydrogenases From The Gill Tissue Of The Ribbed Mussel (Modiolus Demissus) , Mary Michael Brodey

Retrospective Theses and Dissertations

To assess the role of dicarboxylic acid metabolism in the synthesis of alanine and other compounds by the ribbed mussel under conditions of hyperosmotic and anaerobic stress, the cytosolic and mitochondrial malate dehydrogenases and the mitochondrial malic enzyme from this organism were purified and their kinetics studied. Both the cytosolic and mitochondrial malate dehydrogenases were found to be dimers with native M[subscript] r = 60,000. One cMDH allele (designated slow) was found to predominate in populations from Cape Cod, MA. Similar low K[subscript] m's were observed for purified preparations of the slow/slow homodimer (cMDH) and for ...


Characterization Of A Potato Proteinase Inhibitor Ii Gene Whose Expression In Not Wound-Responsive , Sanggyu Park Jan 1991

Characterization Of A Potato Proteinase Inhibitor Ii Gene Whose Expression In Not Wound-Responsive , Sanggyu Park

Retrospective Theses and Dissertations

A potato Proteinase Inhibitor II gene (pin2T) was isolated and characterized both at the molecular level and the functional level. The open reading frame as well as the 5[superscript]' and 3[superscript]' flanking regions were sequenced. The coding region and 3[superscript]' flanking region showed 86% and 87% identity with those of the previously isolated wound-inducible potato Proteinase Inhibitor IIK gene (pin2K) sequence, respectively. However, the 5[superscript]' flanking region of the pin2T is highly homologous (91% identity) with that of pin2K from -767 to +29, relative to the transcription start site of the wound-inducible pin2K. The 5[superscript ...


Studies On The Active Site Of Escherichia Coli Adenylosuccinate Synthetase By Chemical Modification And Site-Directed Mutagenesis , Qun Dong Jan 1991

Studies On The Active Site Of Escherichia Coli Adenylosuccinate Synthetase By Chemical Modification And Site-Directed Mutagenesis , Qun Dong

Retrospective Theses and Dissertations

Reaction of E. coli adenylosuccinate synthetase with thiol reagents leaded to modification of one cysteine residue per subunit without significant loss of enzyme activity. Modification of a second cysteine residue occurred under 3.4 M urea and resulted in complete loss of enzyme activity. The remaining two cystein residues were modified only after treatment with 8 M urea. The reactive cystein had been identified as Cys[superscript]291, and the thiol exposed with 3.5 M urea is Cys[superscript]344. When Cys[superscript]344 was replaced by either serine or alanine, the mutant enzymes were as active as the ...


Selective Labeling Of Peptides, Metalloproteins, And Proteolytic Enzymes With Pt(Ii) Complexes And Electron-Transfer Reactions Of Native And Cross-Linked Metalloproteins , Herb M. Brothers Ii Jan 1991

Selective Labeling Of Peptides, Metalloproteins, And Proteolytic Enzymes With Pt(Ii) Complexes And Electron-Transfer Reactions Of Native And Cross-Linked Metalloproteins , Herb M. Brothers Ii

Retrospective Theses and Dissertations

The transition-metal complex (Pt(trpy)Cl) [superscript]+ selectively labels the amino acids Cys and His, but is unreactive toward Met. The (Pt(trpy)Cl) [superscript]+ complex also forms complexes with nonbiological ligands to form novel compounds with metal-metal or [pi]-[pi] interactions;The homologous gold reagent, (Au(trpy)Cl) [superscript]2+ reacts with Trp, Cys, His, and Met. The oxidative properties of the gold complex makes it an invasive reagent toward proteins, however;In reactions with proteins, the complex (Pt(trpy)Cl) [superscript]+ exhibits unexpected selectivity toward amino acid side chains in cytochromes c. His residues are labeled in greater ...