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

Characterization Of Barley Yellow Dwarf Virus Subgenomic Rnas, Jacquelyn R. Jackson Jan 2008

Characterization Of Barley Yellow Dwarf Virus Subgenomic Rnas, Jacquelyn R. Jackson

Retrospective Theses and Dissertations

Transcription of subgenomic RNAs (sgRNAs) is a common strategy used by many positive strand RNA viruses of plants and animals to regulate viral gene expression. Barley yellow dwarf virus (BYDV) produces three nested 3'-coterminal subgenomic RNAs in infected cells. SgRNA1 serves as the messenger for the structural and movement proteins. sgRNA2 encodes a small open reading frame (ORF6), that appears not to be translated. The role of sgRNA3 is unknown, as it encodes no ORFs. Neither sgRNA2 nor sgRNA3 is needed for BYDV RNA replication in oat protoplasts. However, sgRNA2 does function as a riboregulator of viral translation in ...


Functional Analysis Of The C-Terminal Domain In The Drosophila Jil-1 Histone H3 Kinase, Xiaomin Bao Jan 2008

Functional Analysis Of The C-Terminal Domain In The Drosophila Jil-1 Histone H3 Kinase, Xiaomin Bao

Retrospective Theses and Dissertations

Epigenetic regulation is an important process utilized by biological systems to control gene expression and organize development, with histone modification enzymes among the most important components in this regulatory network. The predominant interphase H3 Serine10 kinase in Drosophila is JIL-1, which plays an important role in regulating chromosome structure and modulating gene expression. The full-length JIL-1 protein is composed of four domains including a N-terminal domain (NTD), two kinase domains (KDI and KDII), and a unique C-terminal domain (CTD). In order to study the biological importance of these individual domains, a domain analysis research approach was taken and different functions ...


Phylogenetic Placement And Population Genetic Analysis Of The Endangered Winged Mapleleaf, Quadrula Fragosa, Amanda Heather Hemmingsen Jan 2008

Phylogenetic Placement And Population Genetic Analysis Of The Endangered Winged Mapleleaf, Quadrula Fragosa, Amanda Heather Hemmingsen

Retrospective Theses and Dissertations

The endangered winged mapleleaf, Quadrula fragosa once occurred in the Mississippi, Tennessee, Ohio, and Cumberland River basins in the United States. While the range of this species was thought to have been reduced to a single population in the St. Croix River (Minnesota/Wisconsin), individuals morphologically similar to Q. fragosa were recently recorded in Missouri, Arkansas, and Oklahoma. We employed a phylogenetic analysis of mitochondrial ND1 gene sequences. Our results indicate that Q. fragosa is a separate species and that the southern populations are genetically Q. fragosa. In addition, we developed and utilized 12 microsatellite loci to quantify genetic variation ...


Relatedness Of Haemophilus Parasuis Strains And Their Proteins' Possible Roles As Virulence Factors, Emilie Susanna Noel Zehr Jan 2008

Relatedness Of Haemophilus Parasuis Strains And Their Proteins' Possible Roles As Virulence Factors, Emilie Susanna Noel Zehr

Retrospective Theses and Dissertations

Haemophilus parasuis, the causative agent of Glasser's disease, is considered to be a remerging pathogen of swine in high-health status herds. Several molecular typing methods have been suggested as alternatives to serotyping, which failed to identify up to 30% of field isolates. This study compared random amplification of polymorphic DNA (RAPD) profiles and protein profiles of H. parasuis reference strains and field isolates as methods for identifying and grouping virulent and avirulent isolates. DNA and protein profiles of 15 reference strains and 31 field isolates of H. parasuis, analyzed with two computer-based similarity analyses, revealed unique and reproducible DNA ...


Mechanisms Of Bes1-Regulated Gene Expression Downstream Of Brassinosteroid Signaling In Arabidopsis Thaliana, Xiaofei Yu Jan 2008

Mechanisms Of Bes1-Regulated Gene Expression Downstream Of Brassinosteroid Signaling In Arabidopsis Thaliana, Xiaofei Yu

Retrospective Theses and Dissertations

Brassinosteroids (BRs), the plant steroid hormones, play an important role in mediating plant responses to developmental and environmental cues. BRs signal through a membrane receptor BRI1 and a GSK3 kinase BIN2 to control the activity of BES1/BZR1 family transcription factors. To understand how BES1 regulates gene expression, I looked into both trans-acting protein factors and cis-acting DNA elements that affect BES1 functions, by yeast genetic screen and chromatin immunoprecipitation coupled with DNA microarray (ChIP-chip), respectively. We identified 1609 BES1 direct target genes and discovered conserved DNA motifs in BES1 binding regions. We also showed that BES1 target genes were ...


Biochemical And Genetic Analyses Of Physical Associations Among Zea Mays Starch Biosynthetic Enzymes, Tracie Ann Hennen-Bierwagen Jan 2008

Biochemical And Genetic Analyses Of Physical Associations Among Zea Mays Starch Biosynthetic Enzymes, Tracie Ann Hennen-Bierwagen

Retrospective Theses and Dissertations

Mutations affecting specific starch biosynthetic enzymes commonly have pleiotropic effects on other enzymes in the same metabolic pathway. Such genetic evidence indicates functional relationships between components of the starch biosynthetic system including starch synthases (SS), starch branching enzymes (BE), and starch debranching enzymes (DBE), however, the molecular explanation for these functional interactions is not known. One possibility is that specific SSs, BEs, and/or DBEs associate physically with each other in multisubunit complexes. To test this hypothesis, this study sought to identify stable associations between SSI, SSIIa, SSIII, SBEI, SBEIIa, and SBEIIb from maize amyloplasts. Three separate detection methods, yeast ...


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 ...


Dissection Of The Mitotic And Nuclear Functions Of Chromator, A Nuclear-Derived Spindle Matrix Component In Drosophila, Yun Ding Jan 2008

Dissection Of The Mitotic And Nuclear Functions Of Chromator, A Nuclear-Derived Spindle Matrix Component In Drosophila, Yun Ding

Retrospective Theses and Dissertations

A spindle matrix has long been proposed to serve as a stationary or elastic molecular matrix substrate for the organization and activities of microtubules and motors, based on the consideration of a mechanical and functional support for the stabilization of microtubule spindle during force generation from mitotic motors. Recently, the identification of four Drosophila proteins, Skeletor, Megator, EAST and Chromator has provided molecular evidence for the existence of this macromolecular matrix structure during mitosis. All of these four proteins have been shown to interact with each other within a protein complex and redistribute from the nucleus at interphase to form ...


Molecular Interactions Of The Mammalian Intermediate Filament Protein Synemin With Cytoskeletal Proteins Present In Adhesion Sites, Ning Sun Jan 2008

Molecular Interactions Of The Mammalian Intermediate Filament Protein Synemin With Cytoskeletal Proteins Present In Adhesion Sites, Ning Sun

Retrospective Theses and Dissertations

The type VI intermediate filament (IF) protein synemin is a very large, unique member of the IF protein superfamily. Synemin associates with the major type III IF protein desmin and/or vimentin forming heteropolymeric intermediate filaments (IFs) within mammalian muscle cells. Previous studies in our lab showed that avian synemin interacts with vinculin and alpha-actinin, both of which are cytoskeletal proteins present in adhesion sites such as the focal adhesions within cells. Thus, synemin may link the heteropolymeric IFs to adhesion sites within mammalian muscle cells or within some non-muscle cells that express synemin. At least two isoforms of synemin ...


Functional Analysis Of Paralogous Genes In Acetyl Coenzyme A Metabolism, Joel D. Schmidt Jan 2008

Functional Analysis Of Paralogous Genes In Acetyl Coenzyme A Metabolism, Joel D. Schmidt

Retrospective Theses and Dissertations

No abstract provided.


A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi Jan 2008

A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi

Retrospective Theses and Dissertations

Programmed Cell Death (PCD) plays a pivotal role in plant development and defense. Pathogen dependent cell-death mutants were used to investigate the complex regulatory pathways between PCD and R-gene mediated resistance. Time-course expression profiles of Blumeria graminis f. sp. hordei (Bgh) challenged C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast-neutron-derived "Bgh-induced tip cell death1" mutant, bcd1, were compared using the 22K Barley1 GeneChip. Contrasts were made to identify genes associated with the cell death phenotype as opposed to R-gene mediated resistance. One hundred eighty-two genes were found in the intersection of these contrasts at a ...


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 ...


Analysis Of Globulin-1 Promoter Activity And The Expression Of Gfp In Transgenic Maize Seed Tissues And Processing Of Gfp-Containing Grain, Colin Shepherd Jan 2007

Analysis Of Globulin-1 Promoter Activity And The Expression Of Gfp In Transgenic Maize Seed Tissues And Processing Of Gfp-Containing Grain, Colin Shepherd

Retrospective Theses and Dissertations

The maize (Zea mays L) kernel is perfectly configured to store proteins and nutrients. The major proteins of the maize kernel are known as seed storage proteins because they have no enzymatic function and they accumulate to a high level for use during germination of the seed as an immediate nutrient source. These seed storage proteins are responsible for much of the nutrient quality of maize when used as a food or feed source. Understanding the regulation of seed storage protein deposition may allow researchers to improve the use of maize grain in a variety of food and feed products ...


Characterization Of Rns2, An S-Like Rnase In Arabidopsis Thaliana Suggests Role In Phosphate Recycling, Saralyn Ohanian Jan 2007

Characterization Of Rns2, An S-Like Rnase In Arabidopsis Thaliana Suggests Role In Phosphate Recycling, Saralyn Ohanian

Retrospective Theses and Dissertations

Ribonucleases play important biological roles within all organisms but many have not been well characterized. The family of T2 RNases is well-conserved throughout the kingdoms of life and yet their properties and functions are not well understood. RNS2 is one of five such RNases found in Arabidopsis, and preliminary evidence shows that it may be involved in phosphate recycling and localized to an intracellular compartment. Using rns2 knock-out mutant plants, I showed that RNS2 has an effect on flowering time during times of phosphate starvation. I also showed that RNS2 is localized to the ER, more specifically, to ER-bodies. To ...


Biotechnological Improvements Of Bio-Based Fuels And Lubricants: Characterization Of Genes For Branched Chain Fatty Acids And Mono-Acyl Esters, Yuqin Jin Jan 2007

Biotechnological Improvements Of Bio-Based Fuels And Lubricants: Characterization Of Genes For Branched Chain Fatty Acids And Mono-Acyl Esters, Yuqin Jin

Retrospective Theses and Dissertations

The goals of the research in this dissertation are to generate the fundamental technologies that can be used to improve the production and quality of vegetable-oil based biodiesel and biolubricants. Specifically, we sought to test the hypothesis that branched chain fatty acids (BCFAs) can substitute for unsaturated fatty acids in maintaining fluidityin an organism. Toward this goal, we examined the utility of two Bacillus keto-acyl synthase III (KASIII) coding genes (yhfB and yjaX) in producing BCFAs. In conducting this research it was necessary to examine if the E. coli KASIII gene (fabH) was essential for initiating fatty acid biosynthesis and ...


Transcriptional Profiling Of Laser-Microdissected Stamen Abscission Zones In Arabidopsis, Suqin Cai Jan 2007

Transcriptional Profiling Of Laser-Microdissected Stamen Abscission Zones In Arabidopsis, Suqin Cai

Retrospective Theses and Dissertations

Organ detachment occurs within cell tiers termed abscission zones (AZs). Characterizations of mutants with aberrant abscission behavior showed abscission to involve multiple signaling pathways. How such pathways are regulated is largely unknown. We examined Arabidopsis abscission zone transcriptome changes associated with floral organ detachment to identify novel shedding regulators. For genomic studies, we used laser capture microdissection (LCM) to dissect AZ cells from surrounding tissues. Because the extremely limited number, small size and close proximity of AZs limited immediate use of LCM, we developed new LCM protocols necessary for genomic studies.;Initial work showed that tape-transfer of paraffin sections to ...


Subcellular Location And Function Of A Putative Juvenile Hormone Esterase Binding Protein In Drosophila Melanogaster, Zhiyan Liu Jan 2007

Subcellular Location And Function Of A Putative Juvenile Hormone Esterase Binding Protein In Drosophila Melanogaster, Zhiyan Liu

Retrospective Theses and Dissertations

Insect development, metamorphosis and reproduction are regulated in part by the action of juvenile hormone (JH). The titer of JH is regulated in turn by the action of the enzymes juvenile hormone epoxide hydrolase and juvenile hormone esterase (JHE). Because of the potential for disruption of regulation of insect development through perturbation of the action of JH, the biology of JHE has been well studied. A putative juvenile hormone esterase binding protein, P29 was identified in the tobacco hornworm, Manduca sexta. Following sequencing of the Drosophila melanogaster genome, we identified a homolog of P29 in D. melanogaster, and used this ...


Genome Rearrangement At Reversed-Ends Ds Element In Arabidopsis, Lakshminarasimhan Krishnaswamy Jan 2007

Genome Rearrangement At Reversed-Ends Ds Element In Arabidopsis, Lakshminarasimhan Krishnaswamy

Retrospective Theses and Dissertations

In course of McClintock's study on radiation induced chromosome breakage, she observed frequent chromosome break generated at a specific locus on chromosome 9. The precision of frequent breaks at this particular locus led to the discovery of Ac/Ds elements. In recent years, molecular characterization of Ac/Ds induced chromosome breaks reveal that when multiple transposon ends are in proximity, the transposase could recognize non-canonical transposon ends resulting in various kinds of chromosomal rearrangements including deletion, inversion, translocation, duplication and, sometimes, chromosome breaks. Previous studies in our lab show that in the maize P1-rr11 allele of the P1 gene ...


The Role Of The Integrase C-Terminus In Replication And Targeted Integration Of The Yeast Retrotransposon Ty5, Troy Leon Brady Jan 2007

The Role Of The Integrase C-Terminus In Replication And Targeted Integration Of The Yeast Retrotransposon Ty5, Troy Leon Brady

Retrospective Theses and Dissertations

Mobile genetic elements have the inherent potential to shape the genomes of their hosts. The retroelements, which include the retrotransposons and retroviruses, are a particularly abundant class of mobile elements. The site of retroelement insertion in the host genome is largely determined by the element-encoded protein integrase (IN). Research presented here addresses three aspects of IN from the retrotransposon Ty5: the function of a conserved domain (GKGY) in the IN C-terminus, the role of IN post-translational modification in targeted integration, and the origin of the Ty5 targeting mechanism.;Sequence analysis of a conserved domain (GKGY) found in the C-termini of ...


Molecular Basis Of Campylobacter Antibiotic Resistance And Adaptation To The Intestinal Tract Of Chickens, Baoqing Guo Jan 2007

Molecular Basis Of Campylobacter Antibiotic Resistance And Adaptation To The Intestinal Tract Of Chickens, Baoqing Guo

Retrospective Theses and Dissertations

Campylobacter is a major foodborne pathogen causing human enteric infections. Antibiotic treatments are needed for prolonged and severe cases of campylobacteriosis, but Campylobacter is increasingly resistant to antimicrobials, which has rendered antimicrobial therapy less effective. Multiple mechanisms contribute to antibiotic resistance in Campylobacter, but antibiotic efflux mediated by membrane transporters is considered a significant player in conferring intrinsic and acquired resistance to a broad spectrum of antimicrobials. The recently published genomic sequence revealed the presence of multiple genes encoding efflux transporters in C. jejuni, and work conducted in our laboratory identified that CmeABC, a RND (resistance nodulation and cell division ...


Characterization Of Three Spindle Matrix Proteins, Megator, East And Asator, In Drosophila, Hongying Qi Jan 2007

Characterization Of Three Spindle Matrix Proteins, Megator, East And Asator, In Drosophila, Hongying Qi

Retrospective Theses and Dissertations

Two previously identified proteins Skeletor and Chromator provide the molecular evidence for the existence of a spindle matrix complex in Drosophila. The spindle matrix has been proposed to be a macromolecular complex, which plays a role in organization and stabilization of the mitotic spindle as well as in providing structural support for counterbalancing force production.;In this dissertation, I present the identification and characterization of three more putative spindle matrix candidate proteins, Megator, EAST and Asator. Megator, an ortholog of the mammalian TPR protein, contains a large coiled-coil domain at its NH2-terminus and an acidic, non-structural COOH-terminus. Immunohistochemistry studies show ...


Mechanism Of Cap-Independent Translation By Long Distance Kissing Stem-Loop Interactions In Plant Viral Rnas, Aurélie Mamisoa Rakotondrafara Jan 2007

Mechanism Of Cap-Independent Translation By Long Distance Kissing Stem-Loop Interactions In Plant Viral Rnas, Aurélie Mamisoa Rakotondrafara

Retrospective Theses and Dissertations

While the presence of a 5' cap and a 3' poly(A) tail are key elements for efficient translation of eukaryotic mRNAs, many viral mRNAs lack one or both of such structures and yet translate efficiently. Owing to the absence of a 5' cap, Barley yellow dwarf virus (BYDV, Luteoviridae family) genomic and subgenomic RNA1 rely on a cap-independent translation element (BTE), which is an RNA domain capable of promoting translation. In contrast to an internal ribosome entry site (IRES), the BTE is located at the 3' end of the viral mRNA, while translation initiation occurs at the 5' end ...


Genesis Of Gene Structures And Computational Analysis Of U12-Type Introns, Matthew Devin Wilkerson Jan 2007

Genesis Of Gene Structures And Computational Analysis Of U12-Type Introns, Matthew Devin Wilkerson

Retrospective Theses and Dissertations

Accurate and prompt gene structure annotation is a necessity for the utilization of genomic sequence data and large scale biological research. As the number of genomes being sequenced rapidly increases, there is a need for immediate gene structure annotation, which is distinct from the whole genome annotation that is conducted at the completion of sequencing. In completely sequenced genomes, inaccuracies in gene structure annotations can make subsequent analysis problematic. For instance, the incorrect assignment of exons to a gene can change the protein coded by the gene, which would have effects on the functional and evolutionary descriptions of the gene ...


The Roles Of Lcn2 In The Inflammatory Lung And Liver, Yinghua Liu Jan 2007

The Roles Of Lcn2 In The Inflammatory Lung And Liver, Yinghua Liu

Retrospective Theses and Dissertations

Uterocalin (Lcn2; also called 24p3, SIP24, or siderocalin and abbreviated as Utc) is an acute phase protein, for which the physiological function remains to be determined. Basal Utc expression is highest in the uterus, mammary gland and lung, which are three tissues with direct exposure to the diverse bacterial flora of the external environment. The demonstrated ability to bind siderophores is one means by which Utc can provide protection against pathogenic bacteria. However, its specificity for siderophores limits the ability of Utc to ward off pathogens. Epithelial tissues that interact with the external environment are exposed to many different nonpathogenic ...


Production Of 3-Hydroxypropionate From Biomass, Netra Rajguru Agarkar Jan 2007

Production Of 3-Hydroxypropionate From Biomass, Netra Rajguru Agarkar

Retrospective Theses and Dissertations

Biorenewable technology is a developing field of science that researches alternative sources for petroleum products like fuels, plastics, paints, etc. The DoE biomass program has identified the 12 top chemicals that can be produced from biomass and further processed to replace many petroleum products; 3-hydroxypropionate (3HP) is a top 12 chemical that can be used to produce plastics, paints, tires, and other consumer products. This thesis describes the attempts to produce 3HP from glucose in E. coli and from syngas in R. rubrum. Malonyl CoA reductase from C. aurantiacus and R. castenholzii was cloned and expressed in E. coli and ...


Cloning, Expression, Purification, And Characterization Of A Glycoside Hydrolase Family 44 Cellulase From Clostridium Acetobutylicum In Escherichia Coli, Taran Christopher Shilling Jan 2007

Cloning, Expression, Purification, And Characterization Of A Glycoside Hydrolase Family 44 Cellulase From Clostridium Acetobutylicum In Escherichia Coli, Taran Christopher Shilling

Retrospective Theses and Dissertations

Glycoside hydrolase family 44 (GH44) remains one of the smallest and least studied families of cellulases. The cellulosome of Clostridium acetobutylicum ATCC 824 contains the gene CAC0915, which codes for a putative extracellular GH44 catalytic domain with a C-terminal type I dockerin domain. The GH44 catalytic domain was synthesized with codon modifications, ligated into the expression vector pET--22b, and transformed into Escherichia coli BL21 (DE3). Expression during cell growth was induced by isopropyl-beta-D-thiogalactopyranoside and the recombinant protein, produced as a fusion protein containing a C-terminal His6-tag, and isolated from the harvested cells' cytoplasm after sonication. The enzyme has a mass ...


Characterization Of The Starch Branching Enzymes In Arabidopsis Thaliana, Qinglei Gan Jan 2007

Characterization Of The Starch Branching Enzymes In Arabidopsis Thaliana, Qinglei Gan

Retrospective Theses and Dissertations

The roles of three starch branching enzyme isoforms, BE1, BE2 and BE3, in Arabidopsis leaf starch metabolism were investigated by AtBE mutant analysis. We also determined the expression patterns of BEs in Arabidopsis by GUS staining and microarray experiments. The possible correlation of BE gene expression with other genes in the Arabidopsis genome was analyzed to identify putative genes that are functionally correlated with BEs. Motifs in the promoters of the Arabidopsis BE genes were identified to better understand their expression differences. BE2 and BE3 expression levels during a diurnal cycle were evaluated with isoform specific antibodies. Meantime, the in ...


Map Based Candidate Gene Cloning And Functional Analysis Of Genes Involved In Vlcfas Synthesis, Li Fan Jan 2007

Map Based Candidate Gene Cloning And Functional Analysis Of Genes Involved In Vlcfas Synthesis, Li Fan

Retrospective Theses and Dissertations

VLCFAs are biosynthesized by an endoplasmic reticulum associated enzyme system, referred to as fatty acid elongase. Fatty acid elongase generates VLCFAs by elongating 18C fatty acids. The enzymatic machinery of fatty acid elongation is believed to be composed of 3-ketoacyl-CoA synthase, 3-ketoacyl-CoA reductase, 3-hydroxyacyl-CoA dehydratase, and enoyl-CoA reductase. However, the insoluble nature of the fatty acid elongase system has hampered efforts to purify the system and to identify the genes that encode the component proteins. In the current study a candidate gene cloning approach was used to demonstrate that the previously defined gl26 gene of maize encodes a predicted enoyl-CoA ...


Genetic And Molecular Analysis Of Starch Synthases Functions In Maize And Arabidopsis , Xiaoli Zhang Jan 2006

Genetic And Molecular Analysis Of Starch Synthases Functions In Maize And Arabidopsis , Xiaoli Zhang

Retrospective Theses and Dissertations

Understanding the specific functions played by individual starch synthase isoforms in maize and Arabidopsis will provide important evidence for how highly organized starch structure is made. Starch synthases (SS) catalyze the transfer of the glucosyl moiety from ADP-Glc to the terminus of a growing alpha-(1, 4)-linked glucan linear chain. At least five classes of SSs are identified in higher species, referred to as GBSS, SSI, SSII, SSIII, and SSIVN. They have high similarity in the catalytic and starch-binding domains of the C-termini but differ at their N-termini. All of these enzymes are highly conserved in plant kingdom, which ...


Functional Characterization Of The Rad51 Genes In Zea Mays And Their Roles In Mu Transposition , Jin Li Jan 2006

Functional Characterization Of The Rad51 Genes In Zea Mays And Their Roles In Mu Transposition , Jin Li

Retrospective Theses and Dissertations

In Saccharomyces cerevisiae, Rad51p plays a central role in homologous recombination and DNA repair. Double mutants of the two Zea mays L. rad51 homologs are viable, but male sterile and have ~22% of normal seed set. Light microscopic analyses of male meiosis in these plants reveal: many chromosomes are unpaired at diakinesis and over 33% of quartets carry cells that either lack a nucleolus or have two nucleoli, indicating that non-disjunction occurs at both meiotic divisions. FISH analysis shows that 70% pachytene cells have paired 5S rDNA loci. Thus, maize RAD51 is required for efficient chromosome pairing and proper chromosome ...