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Articles 1 - 24 of 24

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

Post-Orbital Color Pattern Variation And The Evolution Of A Radiation Of Turtles (Graptemys), Erin M. Myers Jan 2008

Post-Orbital Color Pattern Variation And The Evolution Of A Radiation Of Turtles (Graptemys), Erin M. Myers

Retrospective Theses and Dissertations

One of the most studied areas in the field of evolutionary biology is the formation and maintenance of new species, as well as variation in the rate and extent to which taxa radiate. A range of evolutionary processes, from ecological adaptation to sexual selection and reinforcement, can lead species formation. However, the generation of new species likely results from several isolating mechanisms acting in concert. The map turtle complex (genus: Graptemys) is an excellent model system for exploring the nature of speciation given its exceptional species richness and morphological diversity, particularly in facial coloration patterns. This research utilizes an integrative ...


Taxonomic Review, Phylogeny, And Geographical Population Structure Of The Sawfishes (Chondrichthyes, Pristiformes), Vicente Vieira Faria Jan 2007

Taxonomic Review, Phylogeny, And Geographical Population Structure Of The Sawfishes (Chondrichthyes, Pristiformes), Vicente Vieira Faria

Retrospective Theses and Dissertations

Sawfishes (Pristidae) are considered endangered species worldwide, but their conservation and management have been undermined due to poor understanding of the group's natural taxonomy. The main purpose of this work was to review the taxonomy of sawfishes based on historical taxonomic literature supplemented with empirical observations on morphology, genetics, and geographic distribution. A molecular phylogenetics study based on both mitochondrial and nuclear genes was carried out to estimate the evolutionary interrelationships among the different species of sawfishes. Seven distinct living species are recognized based on external morphology and DNA sequence comparisons. Four are distributed in the Indo-West Pacific, two ...


Posttranslational Processing And Functional Analysis Of Tractin, An L1 Family Member In Leech , Yingzhi Xu Jan 2003

Posttranslational Processing And Functional Analysis Of Tractin, An L1 Family Member In Leech , Yingzhi Xu

Retrospective Theses and Dissertations

During neurogenesis, glycosylated cell adhesion molecules (CAMs) mediate the growth cone navigation and synapse formation. The structure of neuronal CAMs of Ig superfamily is characterized by the variability and complexity of their extracellular region which contain multiple tandemly arranged domains. The diversity in the structure of the neuronal CAMs is generated by alternative splicing and posttranslational modification, such as differential glycosylation and proteolytic processing.;Tractin is a member of the L1-family of neuronal CAMs in leech. It contains six Ig domains, 4 FNIII-like domains, an acidic domain, 12 repeats of a novel proline- and glycine-rich motif (PG/YG) with sequence ...


Protein Structure, Distribution Of Homoplasy And Phylogenetic Inference , Olivier Fedrigo Jan 2003

Protein Structure, Distribution Of Homoplasy And Phylogenetic Inference , Olivier Fedrigo

Retrospective Theses and Dissertations

All molecular phylogenetic methods are based on two assumptions: independence of characters and constant selective pressure. It is well known that these assumptions are often violated, but it is assumed that the methods are robust to such violations. However, the increase of unorthodox phylogenies makes us wonder about their reliability. None of the currently used phylogenetic methods and models account for a change of functional/structural constraint at the protein level. In order to understand the consequences on the phylogenetic inference, I studied the distribution of the structural/functional misleading phylogenetic signal in the tree and described the effect of ...


A Candidate Gene Analysis For Response To Salmonella Enteritidis Challenge Or Vaccination In Young Chicks , Wei Liu Jan 2002

A Candidate Gene Analysis For Response To Salmonella Enteritidis Challenge Or Vaccination In Young Chicks , Wei Liu

Retrospective Theses and Dissertations

Salmonella enteritidis (SE) contamination of poultry products is a major cause of food-borne disease worldwide. The candidate gene approach for identification of quantitative trait loci (QTL) for chicken response to Salmonella enteritidis (SE) was applied in the current study. The Iowa Salmonella Response Resource Population (ISRRP), formed by crossing outbred broiler sires with three diverse, highly inbred dam lines (two major histocompatibility complex-congenic Leghorn lines G-B1 and G-B2 and one Fayoumi line) was studied. The F1 generation was evaluated as young chicks for either bacterial load in spleen and cecum after pathogenic SE inoculation, or antibody level after SE vaccination ...


Expression Of Bovine Mammary Gland Ca2+Atpases , Siriwan Prapong Jan 2000

Expression Of Bovine Mammary Gland Ca2+Atpases , Siriwan Prapong

Retrospective Theses and Dissertations

Control of transcellular Ca2+ fluxes associated with lactation are critical to mammary function and Ca2+ homeostasis. Mammary Ca2+ transport and storage may contribute to the pathological hypocalcemia seen in dairy cows at parturition. RT-PCR and Western Blotting were used to identify which Ca2+ ATPases are present in the bovine mammary gland and in milk fat globule membranes (MFGM). PMCA1, PMCA2 and PMCA4 are plasma membrane Ca2+ ATPases expressed in the bovine mammary gland. A putative Golgi Ca2+ ATPase (bSPCA) is also found in significant amounts in the mammary gland. The expression of Ca2+ ATPases in the bovine mammary gland is ...


Characterization Of [Alpha]-Adrenoceptor-Mediated Contractile Responses In The Isolated Bovine Tail Artery And Vein And An Investigation Of Nerve-Mediated Contraction In The Bovine Tail Artery In Response To Electrical Field Stimulation , Marina Val Ioudina Jan 2000

Characterization Of [Alpha]-Adrenoceptor-Mediated Contractile Responses In The Isolated Bovine Tail Artery And Vein And An Investigation Of Nerve-Mediated Contraction In The Bovine Tail Artery In Response To Electrical Field Stimulation , Marina Val Ioudina

Retrospective Theses and Dissertations

The purpose of this study was to identify alpha-adrenoreceptor types and subtypes mediating contractile responses to adrenergic agonists in the bovine tail artery and vein and to investigate nerve-mediated contraction in the bovine tail artery in response to electrical field stimulation. Isolated tissue bath methods were used to study isometric contractile responses in vessel rings. Electrical field stimulation, under constant current conditions, was used to study vessel contraction as a result of neurotransmitter(s) release from sympathetic nerve terminals;Evidence was obtained for the presence of functional alpha1A- and alpha1D-adrenoceptors in the tail artery. Whether functional alpha 1B-adrenoceptors are present ...


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 ...


The Role Of Rat Brain Ptp-1 Surface Basic Residues In Substrate Reactivity , Deborah Sue Baedke Jan 1996

The Role Of Rat Brain Ptp-1 Surface Basic Residues In Substrate Reactivity , Deborah Sue Baedke

Retrospective Theses and Dissertations

Previous work by others has demonstrated that rat brain protein tyrosine phosphatase (rbPTP-1) exhibited increased reactivity toward substrates containing acidic residues N-terminal to phosphotyrosine. We show that substrates containing a single acidic residue C-terminal to the phosphotyrosine also enhanced reactivity with rbPTP-1. A substrate aspartate residue at the P+2 position exhibited the greatest enhancement of reactivity;Surface basic residues of rbPTP-1 were investigated for their role in the increased reactivity due to substrate acidic residues. Mutation of R47 or K120 to alanine decreased the enhancement of reactivity due to acidic residues N-terminal to phosphotyrosine by 78% and 73% respectively ...


The Relationship Between The Calpain Enzyme System And The Postmortem Degradation Of Selected Myofibrillar Proteins , Elisabeth Jane Huff Lonergan Jan 1995

The Relationship Between The Calpain Enzyme System And The Postmortem Degradation Of Selected Myofibrillar Proteins , Elisabeth Jane Huff Lonergan

Retrospective Theses and Dissertations

The protease [mu]-calpain degrades the myofibrillar proteins titin, nebulin, filamin, desmin and troponin-T. Titin and nebulin have been reported to be affected by sample preparation. This study showed that there was little difference in the rate of degradation of the intact forms due to sample preparation (whole muscle preparations vs. purified myofibrils). The postmortem degradation of titin, nebulin, filamin, desmin, and troponin-T was monitored using SDS-PAGE and Western blotting techniques at 0, 1, 3, 7, 14, 28, and 56 days postmortem. Postmortem aged samples with lower shear force values exhibited faster degradation of the five myofibrillar proteins. Similar degradation ...


Characterization Of A Rat Clonal [Beta]-Cell Line, Rinm5f, In A Passage- And Morphology-Dependent Manner , Bum-Sup Lee Jan 1995

Characterization Of A Rat Clonal [Beta]-Cell Line, Rinm5f, In A Passage- And Morphology-Dependent Manner , Bum-Sup Lee

Retrospective Theses and Dissertations

A novel insulin-like immunoreactivity, adrenergic receptors (ARs) and voltage-dependent Ca[superscript]2+ channels (VDCCs) were characterized in a clonal [beta]-cell line, RINm5F, in a passage- and morphology-dependent manner. The cells exhibited two morphological features; the differentiated cells (DCs) with long neuron-like processes and the undifferentiated cells (UCs) without the processes;As morphology of the cells changed from DCs to UCs, amount of secreted insulin gradually decreased; however, insulin reacted to antiserum vs. bovine insulin (ABI) gradually increased from barely detectable amounts. Immunoblotting and immunocytochemistry showed that antiserum vs. rat insulin reacted with insulin from both cell types. ABI did ...


Sequence Variation Characteristics Of D-Loop, Rrna, Trna, And Polypeptide Coding Region Of Bovine Mitochondrial Dna , Jianming Wu Jan 1995

Sequence Variation Characteristics Of D-Loop, Rrna, Trna, And Polypeptide Coding Region Of Bovine Mitochondrial Dna , Jianming Wu

Retrospective Theses and Dissertations

By cloning and sequencing the mtDNA of cows from different maternal lineages, it was found that multiple heteroplasmic mtDNA states within the D-loop and rRNA genes of mtDNA existed extensively in Holstein cattle. Meanwhile, the nature and transmission of mtDNA were investigated. The mtDNA population in a specific animal was found to be a mixture of different genotypes. Because heteroplasmy was observed frequently and seemingly is persistent, selected amplification of specific mtDNA molecules may not be a part of mtDNA inheritance. At same time, four hypervariable sites were located at nt 169, 216, and 1594 between nt 352 to 364 ...


The Role(S) Of Arginine-Specific Mono(Adp-Ribosyl)Transferase In Skeletal Muscle Cells , Hui-Yu Huang Jan 1995

The Role(S) Of Arginine-Specific Mono(Adp-Ribosyl)Transferase In Skeletal Muscle Cells , Hui-Yu Huang

Retrospective Theses and Dissertations

The overall goal of this research project was to examine the biological function of arginine-specific mono(ADP-ribosyl) transferase in skeletal muscle cells. To better understand the function of this enzyme in skeletal muscle, the experimental approach to accomplish this goal consisted of two specific objectives. The first objective was to identify the protein substrates for this enzyme in myogenic cell cultures and cellular fractions. Embryonic chick primary muscle cell cultures were used as a working system for this purpose. In membrane fractions of 96-h myotube cultures incubated with [[superscript]32 P]NAD under conditions selected for mono(ADP-ribosyl)ation, proteins ...


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 ...


Tissue-Specific Regulation Of 1,25-Dihydroxyvitamin D Action In The Target Tissues Of Rats , Matthew John Beckman Jan 1993

Tissue-Specific Regulation Of 1,25-Dihydroxyvitamin D Action In The Target Tissues Of Rats , Matthew John Beckman

Retrospective Theses and Dissertations

Tissue response to 1,25(OH)[subscript]2D[subscript]3 action was evaluated by examining vitamin D-dependent VDR, 24-OHase, and CaBP mRNA expressions, 24-OHase activities, and VDR concentrations in kidney and intestine. Of 4 groups of rats, 2 groups were fed an adequate vitamin D (300-600 IU/wk), 1.0-1.2% calcium (Ca) diet, designated NC, and 2 groups were fed an adequate vitamin D, 0.02% Ca diet, designated LC. One group from each diet was treated with excess vitamin D[subscript]3 (75,000 IU/wk). These groups were designated NCT and LCT, respectively;Plasma 1,25(OH ...


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 ...


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 ...


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 ...


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 ...


A Novel Insulin From The Bullfrog: Its Structure And Function In Protein Secretion By Hepatocytes , Jocelyn Jean Hulsebus Jan 1987

A Novel Insulin From The Bullfrog: Its Structure And Function In Protein Secretion By Hepatocytes , Jocelyn Jean Hulsebus

Retrospective Theses and Dissertations

Bullfrog insulin was extracted and purified from the pancreas of Rana catesbeiana adults using gel filtration and reverse phase high performance liquid chromatography. Amino acid analysis of bullfrog insulin revealed 52 amino acids instead of the most common number of 51. Hagfish insulin is the only other known insulin with 52 amino acids. The most unique feature of bullfrog insulin is a two amino acid extension on the amino terminus (A1) of the A chain. This is the only insulin to date that has an extension at this position. In mammals, the deletion of A1 glycine or addition of a ...


Isolation And Determination Of Nutritional Factors In Food And Fodder Yeast, Robert Lee Smith Jan 1954

Isolation And Determination Of Nutritional Factors In Food And Fodder Yeast, Robert Lee Smith

Retrospective Theses and Dissertations

No abstract provided.


Metabolism Of Cellulose By Microorganisms Of The Rumen , Warren D. Kitts Jan 1953

Metabolism Of Cellulose By Microorganisms Of The Rumen , Warren D. Kitts

Retrospective Theses and Dissertations

No abstract provided.


Dihydroxyphenylalanine Metabolism By Kidney Tissue , Robert Edward Clegg Jan 1948

Dihydroxyphenylalanine Metabolism By Kidney Tissue , Robert Edward Clegg

Retrospective Theses and Dissertations

No abstract provided.


The Determination Of Ethyl Alcohol In The Blood And Tissues, Its Absorption And Distribution And Its Effect Upon Some Of The Blood Constituents Of The Rat , Velmer Bernel Fish Jan 1942

The Determination Of Ethyl Alcohol In The Blood And Tissues, Its Absorption And Distribution And Its Effect Upon Some Of The Blood Constituents Of The Rat , Velmer Bernel Fish

Retrospective Theses and Dissertations

No abstract provided.