Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 16 of 16

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

Functional Analysis Of Hoxa5: Analysis Of Structural, Behavioral, And Molecular Effects Of Hoxa5 Overexpression In Transgenic Line Hoxa5sv2 , Karin Elizabeth Krieger Jan 2001

Functional Analysis Of Hoxa5: Analysis Of Structural, Behavioral, And Molecular Effects Of Hoxa5 Overexpression In Transgenic Line Hoxa5sv2 , Karin Elizabeth Krieger

Retrospective Theses and Dissertations

The purpose of this research was to provide new information on the role of a murine homeobox gene, Hoxa5, in the development of the central and peripheral nervous systems. Although Hoxa5 is expressed in the brachial spinal cord and enteric neuroblasts during development, no neural phenotype has yet been observed in the Hoxa5 knockout mutant. In the work reported here, functional HOXA5 protein was overexpressed in the developing nervous system in transgenic mice in order to gain insight into the mechanisms by which this gene exerts its effects during development. Evaluation of the phenotypes of F0 transgenics and transgenic animals ...


Response Of Plant Growth And Development To Different Light Conditions In Three Model Plant Systems , Hanhong Bae Jan 2001

Response Of Plant Growth And Development To Different Light Conditions In Three Model Plant Systems , Hanhong Bae

Retrospective Theses and Dissertations

Shade avoidance response to the reduced ratio of red:far-red (R:FR) light was studied in a white aspen Populus alba clone 'Bolleana' using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The response to low R:FR The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were ...


Drosophila Jil-1 Kinase Mediates Histone H3 Ser10 Phosphorylation, Maintains Higher Order Chromatin Structure, And Is Implicated In Dosage Compensation , Yanming Wang Jan 2001

Drosophila Jil-1 Kinase Mediates Histone H3 Ser10 Phosphorylation, Maintains Higher Order Chromatin Structure, And Is Implicated In Dosage Compensation , Yanming Wang

Retrospective Theses and Dissertations

The Drosophila JIL-1 tandem Ser/Thr kinase is associated with chromosomes/chromatin throughout the cell cycle in early embryos and localized to hundreds of sites on the open interband regions on third instar larvae polytene chromosomes. Interestingly, the level of JIL-1 is upregulated on the male X chromosome, which is hypertranscribed for dosage compensation. The distribution of JIL-1 overlaps with that of MSL (male specific lethal) proteins and JIL-1 is associated with the MSL complex.;To further study the function of JIL-1 in vivo, a series of JIL-1 mutants from hypomorphs to null were generated. Analyzing the phenotypes of JIL-1 ...


Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen Jan 2001

Molecular Mechanisms Of Cap And Poly(A) Independent Translation Of Barley Yellow Dwarf Virus Rna , Edwards M. Allen

Retrospective Theses and Dissertations

Barley yellow dwarf virus RNA contains a translation element (3 'TE) that confers efficient cap-independent initiation at the 5 proximal AUG. Direct end-labeling of RNAs verified the absence of a 5 ' modification on virion RNA. Thus BYDV differs from related viruses by having neither a genome-linked protein nor a 5 ' cap. To function in the 3' UTR, the 3 'TE must recruit ribosomes and associated translation factors, and communicate with the 5' end of the mRNA where translation initiates. The communication function is mediated by direct base pairing between the 3'TE and the 5' UTR. We propose that protein ...


Studying The Replication Mechanism Of The Yeast Retrotransposon Ty5 By Molecular And Computational Approaches, Xiang Gao Jan 2001

Studying The Replication Mechanism Of The Yeast Retrotransposon Ty5 By Molecular And Computational Approaches, Xiang Gao

Retrospective Theses and Dissertations

The yeast retrotransposon Ty5 is a Ty1/copia element. It is in the Hemivirus genus of the Pseudoviridae family. The ability to genetically manipulate retrotransposons and the yeast host cell was taken advantage of to explore replication mechanisms unique to Ty5 and common to most retrotransposons. Because of the abundance and diversity of retroelement sequences, along with the fact that many retroelement enzymes have evolved unique functional specificities, computational approaches were also developed to study functional divergence in replication. By screening a randomly mutagenized Ty5 library, two mutations (Y68C, D252N) causing higher transposition frequencies were identified. Both mutations increased Ty5 ...


Phospholipase C Of Clostridium Hemolyticum: Gene Characterization And Proof Of Its Role As A Protective Immunogen In Guinea Pigs , Paul Joseph Hauer Jan 2001

Phospholipase C Of Clostridium Hemolyticum: Gene Characterization And Proof Of Its Role As A Protective Immunogen In Guinea Pigs , Paul Joseph Hauer

Retrospective Theses and Dissertations

The phospholipase C (PLPC) gene from Clostridium hemolyticum was cloned using the polymerase chain reaction. An open reading frame which encodes a 399-amino acid protein, containing a 27-amino acid signal sequence, was identified. The molecular weight of the active protein was 42,869 daltons. A 16-amino acid N-terminal sequence determined by Edman degradation exactly matched the putative amino acid sequence of the gene product. Comparison of the nucleotide and amino acid sequences with Genebank databases demonstrated that the beta toxin of C. hemolyticum exhibits high homology with other bacterial PLPCs. The N-terminal portion of the beta toxin contains the zinc-binding ...


Response To S1 Recurrent Selection And Estimation Of Genetic Parameters In Effective Population Sizes Of The Bs11 Maize Population , Kebede Mulatu Ponta Jan 2001

Response To S1 Recurrent Selection And Estimation Of Genetic Parameters In Effective Population Sizes Of The Bs11 Maize Population , Kebede Mulatu Ponta

Retrospective Theses and Dissertations

Recurrent selection is a cyclical breeding technique that has become popular in comprehensive maize improvement strategies. The magnitude of response in recurrent selection depends upon the modes of gene action and their frequencies in effective population sizes. We studied four effective population sizes with the objectives: (1) to estimate response to selection and inbreeding effects, (2) to partition the response to selection into that due to additive and dominance genetic components, and (3) to examine changes in the correlated traits. Four effective population sizes 5, 10, 20, and 30 were developed by S1-progeny selection in the BS11 maize population using ...


Investigation Of The Effect Of Bcl-2 On Hybridoma Cell Survival , Mark Christopher Mowry Jan 2001

Investigation Of The Effect Of Bcl-2 On Hybridoma Cell Survival , Mark Christopher Mowry

Retrospective Theses and Dissertations

Hybridoma cells are widely used to produce large quantities of monoclonal antibodies for use as medicines and diagnostics. Bcl-2 is an oncogene that has been shown to have an anti-apoptotic effect in many cell lines including hybridomas. This study investigates the effect of various levels of bcl-2 expression on hybridoma cell grown and antibody productivity in both batch and perfusion culture.;H166 hybridomas were transfected with a plasmid containing a bcl-2 insert and stable clones were selected. The cells were grown in spinner flasks in batch mode for twelve days and it was confirmed that expression at high levels allow ...


Genetic Analysis Of Reproductive Traits In Soybean [Glycine Max (L) Merr] , I. Made Tasma Jan 2001

Genetic Analysis Of Reproductive Traits In Soybean [Glycine Max (L) Merr] , I. Made Tasma

Retrospective Theses and Dissertations

The objectives of this study were to: (1) estimate the number of genes controlling photoperiod insensitivity in soybean; (2) map quantitative trait loci controlling flowering time, maturity, and photoperiod insensitivity in soybean; (3) map homologous and cloned flowering time gene sequences in soybean; (4) correlate these sequences with maturity (E) loci by means of near isogenic lines (NILs). Three populations, two F 6:7 recombinant inbred lines of 101 and 100 progeny and an F2:4 G. max x G. soja population (60 progeny), were used. Forty-one NILs were also included. At least three genes were proposed to control photoperiod ...


Photophysics And Light Induced Photobiology Of Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Jaehun Park Jan 2001

Photophysics And Light Induced Photobiology Of Antiviral And Antitumor Agents, Hypericin And Hypocrellin , Jaehun Park

Retrospective Theses and Dissertations

The dissertation mainly focuses on the excited-state photophysics and the light-induced biological activity of hypericin and its analogs.;Femtosecond laser technology has provided the opportunity to investigate the rapid dynamics of these molecules. Fluorescence upconversion measurements, which monitor only emission from the fluorescent singlet state, demonstrate that hexamethoxy hypericin, which possesses no labile protons, has an instantaneous rise time for its transient response. On the other hand, hypericin shows a clear 10-ps rise time. This confirms excited-state H-atom transfer as the primary photophysical process in hypericin.;Femtosecond transient absorption spectroscopy technique is used to determine if excited state H-atom transfer ...


The 1dx5 High Molecular Weight Subunit Gene From Wheat In Transgenic Maize , Varaporn Sangtong Jan 2001

The 1dx5 High Molecular Weight Subunit Gene From Wheat In Transgenic Maize , Varaporn Sangtong

Retrospective Theses and Dissertations

We have developed a method for detecting a transgene and its protein product in maize endosperm that allows the kernel to be germinated after analysis. Our method involves first sampling the endosperm with a hand-held rotary grinder. This tissue is then serially extracted for phenotypic analysis by SDS-PAGE with visualization by total protein staining or immuno-blot detection and genotypic analysis by PCR reactions to detect the transgene. This method is useful for screening transgenic kernels in breeding experiments. We have produced transgenic maize plants containing a wheat Glu-1Dx5 gene encoding the high molecular weight glutenin subunit 1Dx5. Analysis by SDS-PAGE ...


Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu Jan 2001

Functional Analysis Of Photosystem I Complex By Site-Directed Mutagenesis , Wu Xu

Retrospective Theses and Dissertations

Photosystem I, one of the two light driven reaction centers of oxygenic photosynthesis, functions as the light-driven plastocyanin-ferredoxin oxidoreductase in the thylakoid membranes of cyanobacteria and chloroplasts. It is a pigment protein complex with 11--14 proteins and several types of organic (e.g. chlorophyll a) and inorganic energy and electron transfer cofactors (e.g. Fe-S cluster). The objectives of this dissertation are: (i) to demonstrate that the spectroscopic and kinetic properties of photosystem I cofactors are determined by the protein environments, (ii) to determine whether the electron transfer in photosystem I is unidirectional or bidirectional, (iii) to identify which aromatic ...


Molecular And Genetic Characterization Of Rf2, A Mitochondrial Aldehyde Dehydrogenase Gene Required For Male Fertility In Maize (Zea Mays L) , Xiangqin Cui Jan 2001

Molecular And Genetic Characterization Of Rf2, A Mitochondrial Aldehyde Dehydrogenase Gene Required For Male Fertility In Maize (Zea Mays L) , Xiangqin Cui

Retrospective Theses and Dissertations

T-cytoplasm induced male sterility (cms-T) is a maternally inherited inability to produce viable pollen in maize. The causal factor, the URF13 protein, is encoded by the mitochondrial genome and accumulates in the mitochondrial inner membrane. Fertility restoration of cms-T is mediated by the complementary action of two nuclear genes, rf1 and rf2. The rf2 gene was cloned via transposon tagging. Sequence analysis revealed that it has high sequence similarity to mammalian mitochondrial aldehyde dehydrogenases (mtALDHs). Sequence, mRNA, and protein analyses of the spontaneous mutant allele rf2-R213 demonstrated that the ALDH activity is necessary for rf2's function as a cms-T ...


X-Ray Crystallographic Studies Of The Metal Binding Sites On Recombinant Porcine Fructose-1,6-Bisphosphatase , Jun-Yong Choe Jan 2001

X-Ray Crystallographic Studies Of The Metal Binding Sites On Recombinant Porcine Fructose-1,6-Bisphosphatase , Jun-Yong Choe

Retrospective Theses and Dissertations

Fructose 1,6-bisphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11, FBPase; Fructose 1,6-bisphosphate + H2O ⇔ Fructose 6-phosphate + Phosphate) is a key regulatory enzyme in gluconeogenesis. It is a homotetramer with subunit molecular mass of 37 kDa. There are two different quaternary conformations of FBPase: the R-state (the active conformation) and the T-state (the inactive conformation). FBPase is inhibited allosterically by AMP. FBPase requires divalent metal ions (Mg2+, Mn 2+, Zn2+, or Co2+) to hydrolyze fructose 1,6-bisphosphate. Some monovalent cations (K+, Rb+, Tl+ or NH3+) maximize the enzyme activity, whereas lithium ions inhibit the enzyme. Li+ inhibition of FBPase ...


Coordination Of Cell Morphology And Nuclear Division By The Bud Neck Control Ring In Saccharomyces Cerevisiae , Courtney Lynn Thomas Jan 2001

Coordination Of Cell Morphology And Nuclear Division By The Bud Neck Control Ring In Saccharomyces Cerevisiae , Courtney Lynn Thomas

Retrospective Theses and Dissertations

Coordination of daughter cell growth and nuclear division are readily observed but not well understood in the yeast Saccharomyces cerevisiae . A screen was performed to identify mutants which lost this coordination such that they exhibited an elongated cell morphology (improper cell growth), but continued to divide. The results of this screen and suppressor analysis suggests the bud neck ring is a control structure which determines cell morphology as well as nuclear division as an upstream regulator of Cdc28p-cyclin complexes.;The effects of mutations in specific components of the bud neck ring on the assembly of other components into the structure ...


Human Hexokinase: Multiple Mechanisms Of G6p Inhibition , Xiaofeng Liu Jan 2001

Human Hexokinase: Multiple Mechanisms Of G6p Inhibition , Xiaofeng Liu

Retrospective Theses and Dissertations

Human hexokinase I catalyzes the first step in glycolysis, playing a key role in the energy metabolism of brain tissue. The chapters included in this thesis focus on structure-function relationships of hexokinase I. Glucose 6-phosphate (G6P), the reaction product, binds to hexokinase I with apparent negative cooperativity and inhibits catalysis (Chapter II). Both N- and C-terminal binding sites for G6P are functional, yet only one G6P molecule binds to hexokinase I.;A series of site-directed mutations were constructed in the base- and ribose-binding pocket of ATP in C-terminal half of hexokinase I G6P inhibition completely (Chapter III). The same mutations ...