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Articles 1 - 19 of 19

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

The Effects Of Neutrophil-Mediated Damage In Acute Mannheimia (Pasteurella) Haemolytica Pneumonia , Zaher Ahmad Khalil Radi Jan 1999

The Effects Of Neutrophil-Mediated Damage In Acute Mannheimia (Pasteurella) Haemolytica Pneumonia , Zaher Ahmad Khalil Radi

Retrospective Theses and Dissertations

ICAM-1 expression in cattle with Bovine Leukocyte Adhesion Deficiency (BLAD) vs. cattle without BLAD in Mannheimia haemolytica (MH) pneumonia at 2 or 4 hours PI was assessed using in situ hybridization. There was a significant increase in ICAM-1 in bronchiolar and alveolar epithelium and endothelium of arteries and veins in both BLAD and non-BLAD MH-inoculated cattle compared to controls. Highest intensity of ICAM-1 was present in bronchioles while bronchi had the lowest. Most alveolar macrophages and neutrophils in infected lungs expressed ICAM-1. ICAM-1 expression was generally increased in infected BLAD cattle at 2 hours PI compared to non-BLAD but not ...


Molecular And Genetic Analysis Of Jil-1, A Chromatin Associated Protein Kinase Implicated In Transcriptional Regulation In Drosophila , Ye Jin Jan 1999

Molecular And Genetic Analysis Of Jil-1, A Chromatin Associated Protein Kinase Implicated In Transcriptional Regulation In Drosophila , Ye Jin

Retrospective Theses and Dissertations

Chromatin remodeling is an essential step for many chromatin-related fundamental cellular processes, such as gene replication, transcription, recombination and gene silencing. Two classes of protein complexes contribute to chromatin remodeling: protein complexes with ATPase activity and protein complexes capable of enzymatic modifications of chromosomal proteins, especially histones. Compared to well-studied histone acetylation which has been directly linked to gene transcription, the role of histone phosphorylation in chromatin remodeling for gene transcription is still poorly understood although there is some correlation between histone phosphorylation and gene transcription;A novel nuclear tandem protein kinase JIL-1 was cloned and identified in Kristen Johansen ...


Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov Jan 1999

Primary Photoprocesses Of Light-Activated Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Alexandre V. Smirnov

Retrospective Theses and Dissertations

The dissertation focuses on the ultrafast primary photoprocesses of the title anti-viral and anti-cancer agents, whose activity depends on light which is also accompanied by photoacidification in vesicles and living cells;By complementing the techniques of time-resolved absorption spectroscopy with those of fluorescence upconversion and applying them to hypericin, hypocrellin A and B, and their methylated analogs that are unable to execute proton transfer, it was demonstrated that intramolecular excited-state hydrogen atom transfer is a dominant primary nonradiative process;For hypocrellin A in viscous solvents such as octanol and ethylene glycol, an absorption transient of ∼10-ps duration, similar to the ...


Novel G-Dna Binding Proteins From The Ciliate Tetrahymena Thermophila: Purification, Characterization, Cloning And Functional Analyses , Quan Lu Jan 1999

Novel G-Dna Binding Proteins From The Ciliate Tetrahymena Thermophila: Purification, Characterization, Cloning And Functional Analyses , Quan Lu

Retrospective Theses and Dissertations

G-DNA is a family of novel four-stranded DNA structures characterized by motifs called G-quartets. Evidence is growing to suggest that G-DNA exists and plays biological roles in vivo. In order to further elucidate the functions of G-DNA, we have studied proteins that specifically bind to the DNA structure;Two G-DNA binding activities, TGPI and TGP3, were purified from the ciliate Tetrahymena thermophila. Based on the peptide sequences obtained from direct internal peptide sequencing, the cDNAs coding for the genes were cloned. Deduced protein sequences showed that TGP1 and TGP3 are novel proteins but share significant homology with each other. Furthermore ...


Fatty Acid Modification Of Cells In Culture By Overexpression Of Exogenous Desaturases , Travis Jay Knight Jan 1999

Fatty Acid Modification Of Cells In Culture By Overexpression Of Exogenous Desaturases , Travis Jay Knight

Retrospective Theses and Dissertations

COS-1 cells were transfected transiently with expression vectors encoding stearoyl-acyl-carrier-protein desaturase (SACPD) from castor bean, stearoyl-CoA desaturase (SCD) from mice, and a control vector containing SACPD cDNA in reverse orientation. The hypothesis was that both exogenous desaturases would be active in COS-1 cells, thereby increasing the proportion of monounsaturated fatty acids produced by the cells. Messenger RNA and anti-myc immunoreactive proteins were detected at 12 and 24 hours post-transfection respectively and increased through 48 hours post-transfection. When acetate was used as the fatty acid precursor in cultures for a 24-hour period starting 24 hours post-transfection, the ratio of monounsaturated to ...


Genome Reorganization And Non-Linear Transposition In Maize , Jianbo Zhang Jan 1999

Genome Reorganization And Non-Linear Transposition In Maize , Jianbo Zhang

Retrospective Theses and Dissertations

Transposable elements have long been considered as potential agents of large-scale genome reorganization by virtue of their ability to induce chromosomal rearrangements such as deletions, duplications, inversions, and reciprocal translocations. Previous researchers have shown that particular configurations of transposon termini can induce chromosome rearrangements at high frequencies. By analyzing two derivatives of an unstable allele of the maize P1 (pericarp color) gene carrying both a full-length Ac (Activator) transposable element and a Ac terminal fragment termed fAc (fractured Ac) that were recovered from a classical maize ear twinned sector, it were found that the twinned alleles are a large inverted ...


Evaluation Of Mycobacterial Esat-6 As A Type-I Immune Enhancing Adjuvant , Sreekumar Ambalakkat Menon Jan 1999

Evaluation Of Mycobacterial Esat-6 As A Type-I Immune Enhancing Adjuvant , Sreekumar Ambalakkat Menon

Retrospective Theses and Dissertations

The need for improved adjuvants has continued in spite of new vaccination strategies using recombinant proteins and genetic (DNA vectored) vaccines. The Mycobacterium tuberculosis protein ESAT-6 has been shown in mice to be involved in the recall of long-lived immunity and protection in mice against tuberculosis. Thus, this protein could potentially act as a molecular adjuvant enhancing antigen-specific Type I immune responses. This study examined the hypothesis that Es could enhance Type I responses against a second antigen in mice when presented as a fusion with that antigen. This was tested using ESAT-6 fusions with two Mycoplasma hyopneumoniae surface antigens ...


Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan Jan 1999

Genetic And Molecular Characterization Of The Rev Protein Of Equine Infectious Anemia Virus , Michael Andrew Belshan

Retrospective Theses and Dissertations

Members of the lentivirus subfamily of retroviruses are characterized as causing slow, chronic disease. Atypical of other lentiviruses, such as human immunodeficiency virus type 1, equine infectious anemia virus (EIAV) may produce a rapid, variable disease course in horses. Infected horses may undergo an, acute episode of disease involving viremia, fever, and thrombocytopenia. Following this acute period, horses may resolve to an inapparent infection or suffer a chronic period of additional cycles of viremia, fever, and thrombocytopenia. Horses which survive clinical episodes usually become inapparent carriers of the virus for life. Numerous virus and host factors contribute to the phenotypic ...


Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev Jan 1999

Replication Of Barley Yellow Dwarf Virus Rna And Transcriptional Control Of Gene Expression , Guennadi Koev

Retrospective Theses and Dissertations

Barley yellow dwarf virus (BYDV) is an important pathogen of cereal crops. It has a single-stranded positive sense genomic RNA (gRNA), 5.7 kilobases. During infection of a plant cell, BYDV generates a nested set of three subgenomic mRNAs (sgRNAs) for expression of its 3'-proximal genes. The goal of this study was to map and characterize cis-acting RNA signals involved in transcription and replication of BYDV RNA. Three sgRNA promoters and the 3' origin of replication were characterized. The sgRNA1 promoter was mapped to a 98 nt region that contains two stem-loop structures. A combination of primary and secondary ...


Genetic Mobility And Instability Of Retroviral Vector In Vector Producer Cells For Gene Therapy, Won-Bin Young Jan 1999

Genetic Mobility And Instability Of Retroviral Vector In Vector Producer Cells For Gene Therapy, Won-Bin Young

Retrospective Theses and Dissertations

A primary biosafety issue of retroviral vector-mediated gene therapy is the genetic instability of retroviral vectors. Reverse transcription of vector RNA genome is initiated by viral reverse transcriptase (RT) in a virion particle after infection of a target cell. During reverse transcription, abnormal template switches between vector and occasionally co-packaged helper virus in a virion particle can therefore enable helper virus to regain replication elements from the vector and revert to replication-competent retrovirus (RCR). This research was undertaken to study the origins of RT enzyme activities and test the hypothesis that RT enzyme activities are contributed by both exogenous RT ...


The Glycogen Phosphorylase/ Phosphorylase Kinase Interaction: Effects Of Mutations In The Amino-Terminal Region Of Glycogen Phosphorylase , Alyssa Christine Biorn Jan 1999

The Glycogen Phosphorylase/ Phosphorylase Kinase Interaction: Effects Of Mutations In The Amino-Terminal Region Of Glycogen Phosphorylase , Alyssa Christine Biorn

Retrospective Theses and Dissertations

Glycogen phosphorylase is an important enzyme for carbohydrate metabolism in muscle. It uses inorganic phosphate to remove glucose from glycogen, producing glucose-1-phosphate, which can be used for the production of ATP. Inactive glycogen phosphorylase (phosphorylase h) is activated either by the allosteric binding of 5'-AMP, or by phosphorylation by phosphorylase kinase (PhK). Phosphorylation produces phosphorylase a, which is active in the absence of AMP. PhK is the only kinase that can phosphorylate phosphorylase b, which in turn is the only substrate for PhK. This dissertation research has attempted to determine the reasons for this specificity and how these two ...


Oxidizing Side Of The Photosystem I , Jun Sun Jan 1999

Oxidizing Side Of The Photosystem I , Jun Sun

Retrospective Theses and Dissertations

Photosynthesis converts solar energy into the biological sources of energy for the life on our planet. Photosystem I (PSI) is one of the two reaction centers of oxygenic photosynthesis. PSI is a multiheteromeric membrane-protein complex that catalyzes light-driven electron transfer from plastocyanin or cytochrome c6 to ferredoxin. The PsaA and PsaB subunits form the heterodimeric core that harbors the primary electron donor P700. On the oxidizing side of the PSI complex, plastocyanin or cytochrome c6 donates electrons to the P700 reaction center. The objective of this dissertation is to identify elements of molecular recognition on the oxidizing side of PSI ...


Dynamic Changes In The Localization Of Synapse Associated Proteins During Development And Differentiation Of The Mammalian Retina , Mary Heather West Greenlee Jan 1999

Dynamic Changes In The Localization Of Synapse Associated Proteins During Development And Differentiation Of The Mammalian Retina , Mary Heather West Greenlee

Retrospective Theses and Dissertations

We have examined the developmental distribution and differential localization of presynaptic terminal associated proteins in the mammalian retina. We have used antibodies specific for synaptic vesicle associated proteins Synaptotagmin, Rab 3A, Synaptophysin and Synaptobrevin, and presynaptic terminal membrane associated proteins SNAP-25 and Syntaxin, to characterize their spatio-temporal distribution during retinal differentiation and in the mature retina;The vertebrate retina has a laminar organization consisting of three cellular layers separated by two synaptic layers, the inner piexiform layer and the outer plexiform layer. In general, immunoreactivity for presynaptic terminal associated proteins was first observed in cellular layers, and as differentiation progressed ...


Transposon-Induced Homologous Recombination At The Maize P Locus And In Transgenic Arabidopsis , Yongli Xiao Jan 1999

Transposon-Induced Homologous Recombination At The Maize P Locus And In Transgenic Arabidopsis , Yongli Xiao

Retrospective Theses and Dissertations

The maize P gene encodes a Myb-homologous regulator of red phlobaphene pigment biosynthesis in the pericarp, cob and other floral tissues. The P locus has a unique structure with two 5.2kb direct repeats flanking the P gene coding region. When the transposon (Ac) inserts into one site between the two direct repeats in the P-ovov-1114 allele, homologous recombination between the two 5.2kb repeats can occur and the whole P gene coding sequence is deleted;To further study this transposon-induced homologous recombination. This study examined six alleles that carry Ac insertions at different sites in the P locus, in ...


Biochemical Characterization And Positional Cloning Of The Var2 Variegation Mutant Of Arabidopsis Thaliana , Meng Chen Jan 1999

Biochemical Characterization And Positional Cloning Of The Var2 Variegation Mutant Of Arabidopsis Thaliana , Meng Chen

Retrospective Theses and Dissertations

Chloroplasts differentiation and development are highly coordinated with their host cells. To better elucidate the mechanisms involved in nuclear-chloroplast interactions, we characterized a nuclear encoded leaf variegation mutation called var2. While cotyledons appear normal, true leaves of var2 emerge as yellow, then turn into green-white sectors. The green sectors contain cells with normal chloroplasts, whereas the white sectors contain cells with abnormal plastid lacking of internal membrane structures. The phenotypes suggested that VAR2 might be involved in thylakoid biogenesis in early chloroplast differentiation. We cloned the VAR2 gene by a map-based method. Five original and two potential alleles were sequenced ...


Evaluation Of Recurrent Selection In Leaming And Midland Maize Populations , Marcelo Javier Carena Jan 1999

Evaluation Of Recurrent Selection In Leaming And Midland Maize Populations , Marcelo Javier Carena

Retrospective Theses and Dissertations

Rates of maize (Zea mays L.) yield improvement in the United States has been reduced during the 1990's. Double-cycle breeding in a few old inbred lines and limited germplasm evaluation and utilization are possible explanations. Only one heterotic pattern (Iowa Stiff Stalk Synthetic x Lancaster Sure Crop) is being widely exploited in U.S. dent maize breeding programs. Alternative U.S. heterotic patterns have been suggested, but they received limited attention and improvement. The objectives of this research were to evaluate inbred-progeny recurrent selection in Leaming (originated in Ohio), the oldest known U.S. open-pollinated variety, and Midland Yellow ...


Assessment Of Plant Introductions For Increasing The Genetic Variability Of Soybean Populations , James Mark Narvel Jan 1999

Assessment Of Plant Introductions For Increasing The Genetic Variability Of Soybean Populations , James Mark Narvel

Retrospective Theses and Dissertations

Plant introductions (PIs) may increase the genetic variability of soybean populations and lead to greater genetic gains from selection. Five soybean populations containing different percentages of PI parentage were developed at Iowa State University to evaluate the use of PIs for increasing genetic variability for seed yield in a recurrent selection program. The objective of this study was to evaluate the performance and genetic variability of the Cycle 4 (C4) populations of AP 10 (100 % PI), AP 11 (75 % PI), AP12 (50 % PI), AP13 (25 % PI), and AP14 (0 % PI) for agronomic traits and seed composition. Multiplexing technology for simple ...


Molecular Characterization Of Myb-Homologous Transcriptional Factors Of The Flavonoid Pathway In Zea Mays , Peifen Zhang Jan 1999

Molecular Characterization Of Myb-Homologous Transcriptional Factors Of The Flavonoid Pathway In Zea Mays , Peifen Zhang

Retrospective Theses and Dissertations

Structural genes encoding enzymes that catalyze each step of flavonoid synthesis are temporally and spatially regulated. It has been shown that specific anthocyanin pigmentation patterns in maize are achieved by the tissue-specific expression of regulatory genes. Moreover, this tissue-specific regulation is a consequence of the generation of different alleles or duplicated copies of regulatory genes during evolution;In contrast, the myb-homologous P1 gene was the only known regulatory gene required for phlobaphene biosynthesis. The isolation and characterization of the P2 gene, reported here, provides direct molecular evidence that the P region contains duplicated genes. Furthermore, the duplicated P1 (herein, P1-rr ...


Selection For Soybean Seed Yield With Molecular Markers , Joseph Richard Byrum Jan 1999

Selection For Soybean Seed Yield With Molecular Markers , Joseph Richard Byrum

Retrospective Theses and Dissertations

Molecular markers may facilitate the identification of and selection for quantitative trait loci (QTL) that control economically important traits. The objective of the study was to compare the efficiency of selection among soybean [Glycine max (L.) Merrill] lines for seed yield based on single replication progeny-row-yield tests (PRYT), molecular marker loci selected by pedigree analysis, and a combination of PRYT and molecular marker data. A total of 380 random F3-derived lines from three populations were evaluated in the PRYT at Ames, IA, in 1997 and were genotyped for simple sequence repeats (SSRs) that had been chosen by pedigree analysis for ...