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Full-Text Articles in Life Sciences

Drosophila Rnase Z Processes Mitochondrial And Nuclear Pre-Trna 3′ Ends In Vivo, Edward B. Dubrovsky, Veronica A. Dubrovskaya, Louis Levinger, Steffen Schiffer, Anita Marchfelder Nov 2004

Drosophila Rnase Z Processes Mitochondrial And Nuclear Pre-Trna 3′ Ends In Vivo, Edward B. Dubrovsky, Veronica A. Dubrovskaya, Louis Levinger, Steffen Schiffer, Anita Marchfelder

Open Dartmouth: Faculty Open Access Scholarship

Although correct tRNA 3′ ends are crucial for protein biosynthesis, generation of mature tRNA 3′ ends in eukaryotes is poorly understood and has so far only been investigated in vitro. We report here for the first time that eukaryotic tRNA 3′ end maturation is catalysed by the endonuclease RNase Z in vivo. Silencing of the JhI‐1 gene (RNase Z homolog) in vivo with RNAi in Drosophila S2 cultured cells causes accumulation of nuclear and mitochondrial pre‐tRNAs, suggesting that JhI‐1 encodes both forms of the tRNA 3′ endonuclease RNase Z, and establishing its biological role in endonucleolytic tRNA ...


Electrotransformation Of Clostridium Thermocellum, Michael V. Tyurin, Sunil G. Desai, Lee R. Lynd Nov 2004

Electrotransformation Of Clostridium Thermocellum, Michael V. Tyurin, Sunil G. Desai, Lee R. Lynd

Open Dartmouth: Faculty Open Access Scholarship

Electrotransformation of several strains of Clostridium thermocellum was achieved using plasmid pIKm1 with selection based on resistance to erythromycin and lincomycin. A custom-built pulse generator was used to apply a square 10-ms pulse to an electrotransformation cuvette consisting of a modified centrifuge tube. Transformation was verified by recovery of the shuttle plasmid pIKm1 from presumptive transformants of C. thermocellum with subsequent PCR specific to the mls gene on the plasmid, as well as by retransformation of Escherichia coli. Optimization carried out with strain DSM 1313 increased transformation efficiencies from <1 to (2.2 􏰍 0.5) 􏰎 105 transformants per 􏰃g of plasmid DNA. Factors conducive to achieving high transformation efficiencies included optimized periods of incubation both before and after electric pulse application, chilling during cell collection and washing, subculture in the presence of isoniacin prior to electric pulse application, a custom-built cuvette embedded in an ice block during pulse application, use of a high (25-kV/cm) field strength, and induction of the mls gene before plating the cells on selective medium. The protocol and preferred conditions developed for strain DSM 1313 resulted in transformation efficiencies of (5.0 􏰍 1.8) 􏰎 104 transformants per 􏰃g of plasmid DNA for strain ATCC 27405 and 􏰁1 􏰎 103 transformants per 􏰃g of plasmid DNA for strains DSM 4150 and 7072. Cell viability under optimal conditions was 􏰁50% of that of controls not exposed to an electrical pulse. Dam methylation had a beneficial but modest (7-fold for strain ATCC 27405; 40-fold for strain DSM 1313) effect on transformation efficiency. The effect of isoniacin was also strain specific. The results reported here provide for the first time a gene transfer method functional in C. thermocellum that is suitable for molecular manipulations involving either the introduction of genes associated with foreign gene products or knockout of native genes.


The Caenorhabditis Elegans F-Box Protein Sel-10 Promotes Female Development And May Target Fem-1 And Fem-3 For Degradation By The Proteasome, Sibylle Jager, Hillel T. Schwartz, H. Robert Horvitz, Barbara Conradt Aug 2004

The Caenorhabditis Elegans F-Box Protein Sel-10 Promotes Female Development And May Target Fem-1 And Fem-3 For Degradation By The Proteasome, Sibylle Jager, Hillel T. Schwartz, H. Robert Horvitz, Barbara Conradt

Open Dartmouth: Faculty Open Access Scholarship

The Caenorhabditis elegans F-box protein SEL-10 and its human homolog have been proposed to regulate LIN-12 Notch signaling by targeting for ubiquitin-mediated proteasomal degradation LIN-12 Notch proteins and SEL-12 PS1 presenilins, the latter of which have been implicated in Alzheimer's disease. We found that sel-10 is the same gene as egl-41, which previously had been defined by gain-of-function mutations that semidominantly cause masculinization of the hermaphrodite soma. Our results demonstrate that mutations causing loss-of-function of sel-10 also have masculinizing activity, indicating that sel-10 functions to promote female development. Genetically, sel-10 acts upstream of the genes fem-1, fem-2, and fem-3 ...


Pf15p Is The Chlamydomonas Homologue Of The Katanin P80 Subunit And Is Required For Assembly Of Flagellar Central Microtubules, Erin E. Dymek, Paul A. Lefebvre, Elizabeth F. Smith Aug 2004

Pf15p Is The Chlamydomonas Homologue Of The Katanin P80 Subunit And Is Required For Assembly Of Flagellar Central Microtubules, Erin E. Dymek, Paul A. Lefebvre, Elizabeth F. Smith

Open Dartmouth: Faculty Open Access Scholarship

Numerous studies have indicated that the central apparatus plays a significant role in regulating flagellar motility, yet little is known about how the central pair of microtubules or their associated projections assemble. Several Chlamydomonas mutants are defective in central apparatus assembly. For example, mutant pf15 cells have paralyzed flagella that completely lack the central pair of microtubules. We have cloned the wild-type PF15 gene and confirmed its identity by rescuing the motility and ultrastructural defects in two pf15 alleles, the original pf15a mutant and a mutant generated by insertional mutagenesis. Database searches using the 798-amino-acid polypeptide predicted from the complete ...


Identification Of Sarv (Sa2062), A New Transcriptional Regulator, Is Repressed By Sara And Mgra (Sa0641) And Involved In The Regulation Of Autolysis In Staphylococcus Aureus, Adhar C. Manna, Susham S. Ingavale, Marybeth Maloney, Willem Van Wamel, Ambrose L. Cheung Aug 2004

Identification Of Sarv (Sa2062), A New Transcriptional Regulator, Is Repressed By Sara And Mgra (Sa0641) And Involved In The Regulation Of Autolysis In Staphylococcus Aureus, Adhar C. Manna, Susham S. Ingavale, Marybeth Maloney, Willem Van Wamel, Ambrose L. Cheung

Open Dartmouth: Faculty Open Access Scholarship

The expression of genes involved in the pathogenesis of Staphylococcus aureus is known to be controlled by global regulatory loci, including agr, sarA, sae, arlRS, lytSR, and sarA-like genes. Here we described a novel transcriptional regulator called sarV of the SarA protein family. The transcription of sarV is low or undetectable under in vitro conditions but is significantly augmented in sarA and mgrA (norR or rat) (SA0641) mutants. The sarA and mgrA genes act as repressors of sarV expression, as confirmed by transcriptional fusion and Northern analysis data. Purified SarA and MgrA proteins bound specifically to separate regions of the ...


Sadb Is Required For The Transition From Reversible To Irreversible Attachment During Biofilm Formation By Pseudomonas Aeruginosa Pa14, Nicky C. Caiazza, George A. O'Toole Jul 2004

Sadb Is Required For The Transition From Reversible To Irreversible Attachment During Biofilm Formation By Pseudomonas Aeruginosa Pa14, Nicky C. Caiazza, George A. O'Toole

Open Dartmouth: Faculty Open Access Scholarship

Current models of biofilm formation by Pseudomonas aeruginosa propose that (i) planktonic cells become surface associated in a monolayer, (ii) surface-associated cells form microcolonies by clonal growth and/or aggregation, (iii) microcolonies transition to a mature biofilm comprised of exopolysaccharide-encased macrocolonies, and (iv) cells exit the mature biofilm and reenter the planktonic state. Here we report a new class of P. aeruginosa biofilm mutant that defines the transition from reversible to irreversible attachment and is thus required for monolayer formation. The transposon insertion carried by the sadB199 mutant was mapped to open reading frame PA5346 of P. aeruginosa PA14 and ...


Pv1 Is A Key Structural Component For The Formation Of The Stomatal And Fenestral Diaphragms, Radu V. Stan, Eugene Tkachenko, Ingrid R. Niesman May 2004

Pv1 Is A Key Structural Component For The Formation Of The Stomatal And Fenestral Diaphragms, Radu V. Stan, Eugene Tkachenko, Ingrid R. Niesman

Open Dartmouth: Faculty Open Access Scholarship

PV1 is an endothelial-specific integral membrane glycoprotein associated with the stomatal diaphragms of caveolae, transendothelial channels, and vesiculo-vacuolar organelles and the diaphragms of endothelial fenestrae. Multiple PV1 homodimers are found within each stomatal and fenestral diaphragm. We investigated the function of PV1 within these diaphragms and their regulation and found that treatment of endothelial cells in culture with phorbol myristate acetate (PMA) led to upregulation of PV1. This correlated with de novo formation of stomatal diaphragms of caveolae and transendothelial channels as well as fenestrae upon PMA treatment. The newly formed diaphragms could be labeled with anti-PV1 antibodies. The upregulation ...


Estimating Metazoan Divergence Times With A Molecular Clock, Kevin J. Peterson, Jessica B. Lyons, Kristin S. Nowak, Carter M. Takacs, Matthew J. Wargo, Mark A. Mcpeek Apr 2004

Estimating Metazoan Divergence Times With A Molecular Clock, Kevin J. Peterson, Jessica B. Lyons, Kristin S. Nowak, Carter M. Takacs, Matthew J. Wargo, Mark A. Mcpeek

Open Dartmouth: Faculty Open Access Scholarship

Accurately dating when the first bilaterally symmetrical animals arose is crucial to our understanding of early animal evolution. The earliest unequivocally bilaterian fossils are 555 million years old. In contrast, molecular-clock analyses calibrated by using the fossil record of vertebrates estimate that vertebrates split from dipterans (Drosophila) 900 million years ago (Ma). Nonetheless, comparative genomic analyses suggest that a significant rate difference exists between vertebrates and dipterans, because the percentage difference between the genomes of mosquito and fly is greater than between fish and mouse, even though the vertebrate divergence is almost twice that of the dipteran. Here we show ...


The C. Elegans Heterochronic Gene Lin-46 Affects Developmental Timing At Two Larval Stages And Encodes A Relative Of The Scaffolding Protein Gephyrin, A. S.-R. Pepper, Jill E. Mccane, Kevin Kemper, Dennis Au Yeung, Rosalind C. Lee, Victor Ambros, Eric G. Moss Apr 2004

The C. Elegans Heterochronic Gene Lin-46 Affects Developmental Timing At Two Larval Stages And Encodes A Relative Of The Scaffolding Protein Gephyrin, A. S.-R. Pepper, Jill E. Mccane, Kevin Kemper, Dennis Au Yeung, Rosalind C. Lee, Victor Ambros, Eric G. Moss

Open Dartmouth: Faculty Open Access Scholarship

The succession of developmental events in the C. elegans larva is governed by the heterochronic genes. When mutated, these genes cause either precocious or retarded developmental phenotypes, in which stage-specific patterns of cell division and differentiation are either skipped or reiterated, respectively. We identified a new heterochronic gene, lin-46, from mutations that suppress the precocious phenotypes caused by mutations in the heterochronic genes lin-14 and lin-28. lin-46 mutants on their own display retarded phenotypes in which cell division patterns are reiterated and differentiation is prevented in certain cell lineages. Our analysis indicates that lin-46 acts at a step immediately downstream ...


Decreased Expression Of Cu–Zn Superoxide Dismutase 1 In Ants With Extreme Lifespan, Joel D. Parker, Karen M. Parker, Barbara H. Sohal, Rajindar S. Sohal, Laurent Keller Mar 2004

Decreased Expression Of Cu–Zn Superoxide Dismutase 1 In Ants With Extreme Lifespan, Joel D. Parker, Karen M. Parker, Barbara H. Sohal, Rajindar S. Sohal, Laurent Keller

Joel D Parker

Reactive oxygen species, the by-products of oxidative energy metabolism, are considered a main proximate cause of aging. Accordingly, overexpression of the enzyme Cu–Zn superoxide dismutase 1 (SOD1) can lengthen lifespan of Drosophila melanogaster in the laboratory. However, the role of SOD1 as a main determinant of lifespan has been challenged on the grounds that overexpression might be effective only in compromised genetic backgrounds. Moreover, interspecific comparisons show lower levels of antioxidant activities in longer-lived species, suggesting that life-span extension may evolve through less reactive oxygen species generation from the mitochondria rather than higher expression of SOD1. The tremendous variation ...


A Dominant-Negative Fur Mutation In Bradyrhizobium Japonicum, Heather P. Benson, Kristin Levier, Mary Lou Guerinot Mar 2004

A Dominant-Negative Fur Mutation In Bradyrhizobium Japonicum, Heather P. Benson, Kristin Levier, Mary Lou Guerinot

Open Dartmouth: Faculty Open Access Scholarship

In many bacteria, the ferric uptake regulator (Fur) protein plays a central role in the regulation of iron uptake genes. Because iron figures prominently in the agriculturally important symbiosis between soybean and its nitrogen-fixing endosymbiont Bradyrhizobium japonicum, we wanted to assess the role of Fur in the interaction. We identified a fur mutant by selecting for manganese resistance. Manganese interacts with the Fur protein and represses iron uptake genes. In the presence of high levels of manganese, bacteria with a wild-type copy of the furgene repress iron uptake systems and starve for iron, whereas fur mutants fail to repress ...


Molecular Mechanism Of Imprinting Of The Maize Endosperm Gene Fie1 , Pedro Hermon-Cruz Jan 2004

Molecular Mechanism Of Imprinting Of The Maize Endosperm Gene Fie1 , Pedro Hermon-Cruz

Retrospective Theses and Dissertations

The main purpose of this study was to characterize the expression patterns of the maize fie genes and to identify possible modes of their regulation. Our study revealed that although the fie1 and fie2 genes in maize contain a 78% homology within their exonic regions, their promoter regions are complex and contain no similarity. The maize fie1 and fie2 genes also have different pattern of expression. fie1 has a highly regulated expression. fie1 transcription is detectable only in the endosperm at early stages of development. fie2 has a more ubiquitous expression, detectable in vegetative and reproductive tissues at all times ...


Characterization Of Rev Variants Selected During Chronic And Inapparent Stages Of Equine Infectious Anemia Virus Infection, Wendy Olissa Sparks Jan 2004

Characterization Of Rev Variants Selected During Chronic And Inapparent Stages Of Equine Infectious Anemia Virus Infection, Wendy Olissa Sparks

Retrospective Theses and Dissertations

Equine infectious anemia virus (EIAV) exhibits a high rate of genetic variation in vivo and results in a clinically variable disease in infected horses. Previous studies identified distinct subpopulations within the Rev quasispecies of an experimentally infected pony, pony 524. The subpopulations showed significantly different phenotypes, as measured by in vitro assays, and fluctuated in dominance in a manner coincident with clinical stage of disease. This study further characterizes the genotypic and phenotypic variation within and between the previously identified EIAV Rev subpopulations in pony 524, and characterizes the EIAV Rev quasispecies of another EIAV-infected pony, pony 625. Within pony ...


A Literature Review Of Swine Heat Production, Tami M. Brown-Brandl, John A. Nienaber, Hongwei Xin, Richard S. Gates Jan 2004

A Literature Review Of Swine Heat Production, Tami M. Brown-Brandl, John A. Nienaber, Hongwei Xin, Richard S. Gates

Agricultural and Biosystems Engineering Publications

Current ASAE standards of heat and moisture production (HP, MP) for swine are primarily based on data collected nearly four decades ago. Feedstuffs, management practices, growth rate, and lean percentage of swine have changed HP and MP considerably in that time period. Literature data shows that lean percent increased 1.55% in the last 10 years, resulting in an increase in HP by approximately 15%. Data were compiled into two categories: prior to 1988, and 1988 to present. Analysis of this data revealed that HP increased 12.4% to 35.3% between the two categories, with the largest differences occurring ...


The Central Role Of Acetyl-Coa In Plant Metabolism, As Examined Through Studies Of Atp Citrate Lyase And The Bio1 Mutant Of Arabidopsis , Elizabeth K. Winters Jan 2004

The Central Role Of Acetyl-Coa In Plant Metabolism, As Examined Through Studies Of Atp Citrate Lyase And The Bio1 Mutant Of Arabidopsis , Elizabeth K. Winters

Retrospective Theses and Dissertations

The acetyl-CoA/biotin network encompasses acetyl-CoA generation and utilization, biotin synthesis, recovery, and transport, and myriad metabolic processes requiring biotin-containing enzymes. To expand understanding of this network and its control, plants with altered levels of ACL (ATP citrate lyase) and BIO1 (adenosylmethionine-8-amino-7-oxononanoate synthase) were examined.;An inducible promoter provides a powerful method to test the effects of altered expression of specific genes. The synthetic GVG promoter, reported to be sterol-inducible in Arabidopsis thaliana, was inducible in Glycine max (soybean) when used to control the GUS reporter gene, or the ACLA or ACLB genes. It showed the same unique pattern in ...


Molecular, Bioinformatic And Statistical Approaches To Identify Genes Underlying Complex Traits In Livestock , Laura Grapes Jan 2004

Molecular, Bioinformatic And Statistical Approaches To Identify Genes Underlying Complex Traits In Livestock , Laura Grapes

Retrospective Theses and Dissertations

One of the primary goals for molecular geneticists working with livestock species is to identify and characterize genes underlying complex traits, the so-called quantitative trait loci (QTL). The primary strategy for identifying QTL involves several steps, one being fine mapping of a previously defined chromosomal region and another being identification of candidate genetic polymorphisms that may cause differences in phenotype. The studies presented in this dissertation address fine mapping methodology, use of the candidate gene approach for directly identifying candidate genetic polymorphisms and use of bioinformatic tools for identifying genetic polymorphisms in silico. Results from simulation studies suggest that two ...


Expression Analysis Of Maize Opaque2 Mutants And Glu-1dx5 Transgenic Corn , Hongwu Jia Jan 2004

Expression Analysis Of Maize Opaque2 Mutants And Glu-1dx5 Transgenic Corn , Hongwu Jia

Retrospective Theses and Dissertations

The maize (Zea mays L.) opaque2 (o2) mutant has high lysine content, but soft and starchy kernels. We confirm that Lys content, kernel density, and reduction of zein proteins in o2 mutants are genetic-background dependent. Microarray analysis was carried out by pooling the same amount of mRNA from eight o2 lines to probe the maize Unigene cDNA chip to understand the o2 main effects. 202 genes identified as differentially expressed fit our definition of main effect genes. Comparative analysis of the expression profiles of two additional inbred lines shows that B46WT/B46 o2 with the most extreme phenotype has the ...


Gene Regulation Of Rna Viruses With Uncapped And Non-Polyadenylated Genomic Rna , Ruizhong Shen Jan 2004

Gene Regulation Of Rna Viruses With Uncapped And Non-Polyadenylated Genomic Rna , Ruizhong Shen

Retrospective Theses and Dissertations

New roles of RNAs as regulators of gene expression have emerged and expanded in recent years. However, gene regulation by viral RNA in trans is less noted and not well understood. Barley yellow dwarf virus (BYDV) is a positive sense RNA virus with a single genomic RNA (gRNA). As it replicates it generates three subgenomic RNAs (sgRNA). Data in this dissertation show that BYDV sgRNA2 serves as a regulatory RNA to control viral gene expression. In vitro and In vivo, BYDV sgRNA2 inhibits translation of gRNA, but has less or little effect on translation of sgRNA1, respectively. These data support ...


An Agent-Based Computational Model Of The Evolution Of Reproductive Isolation In Populations Of Digital Plants , Nicole Patricia Leahy Jan 2004

An Agent-Based Computational Model Of The Evolution Of Reproductive Isolation In Populations Of Digital Plants , Nicole Patricia Leahy

Retrospective Theses and Dissertations

The process of speciation is a fascinating area of research in the biological sciences. Development of mathematical and computational models are an important part of developing speciation theory. The Pseudophyte Evolutionary Algorithm PEA is a individual-based population model developed to test hypotheses concerning process of speciation. The individuals pseudophytes are digital "plants." Biologically, they are haploid annuals, each producing pollen and ovules. Pseudophytes are implemented as binary strings representing loci which encoded six traits. Loci were divided into two chromosomes each with three traits. The loci are mapped to a phenotype which determines the behavior of the pseudophyte. The PEA ...


Genetic Analysis Of Complex Traits In Alfalfa (Medicago Sativa L) , Joseph Gary Robins Jan 2004

Genetic Analysis Of Complex Traits In Alfalfa (Medicago Sativa L) , Joseph Gary Robins

Retrospective Theses and Dissertations

The genetic structure of complex agronomic traits in alfalfa ( Medicago sativa) is not well understood. By crossing the subspecies M. sativa subsp. falcata and M. sativa subsp. sativa, a fullsib F1 population was created from which a genetic linkage map of each parental genome was developed using RFLP and SSR markers. These maps include simplex, duplex, and simplex-simplex alleles along with a number of alleles exhibiting segregation distortion. The inclusion of these more complicated segregation ratios resulted in greater saturation of the genome, a better convergence to eight consensus linkage groups, and a more realistic view of regions of the ...


Investigating The Influence Of Cadmium Stress On Glutathione Metabolism Utilizing Mutant And Transgenic Arabidopsis Plants , Annita Gatherum Peterson Jan 2004

Investigating The Influence Of Cadmium Stress On Glutathione Metabolism Utilizing Mutant And Transgenic Arabidopsis Plants , Annita Gatherum Peterson

Retrospective Theses and Dissertations

Glutathione (GSH) has long been known to be an essential molecule in a number of important basic cellular functions including detoxification of reactive oxygen species, transport and storage of organic sulfur, and regulation of the cell cycle. Furthermore, GSH is essential in the detoxification of some heavy metals including cadmium through the production of phytochelatins. Because the accounts of heavy metal pollution are increasing due to human activities, heavy metal toxicity in plants is an important topic of study. To investigate the role of GSH-related functions in response to cadmium exposure I examined three distinct levels of GSH involvement in ...


Computational And Molecular Analysis Of Myb Gene Family, Cizhong Jiang Jan 2004

Computational And Molecular Analysis Of Myb Gene Family, Cizhong Jiang

Retrospective Theses and Dissertations

Myb proteins are defined by a highly conserved DNA-specific binding domain termed Myb, which is composed of approximately 50 amino acids with constantly spaced tryptophan residues. Multiple copies of Myb domains often exist as tandem repeats within a single protein. There are up to four tandem Myb repeats present in Myb proteins identified to date (termed R0R1R2R3 hereafter).;In our study, we collected additional Myb genes, and performed a series of phylogenetic analyses to explore the evolutionary origin of Myb genes. The results suggest that the Myb gene family originated from an ancient one Myb-box gene. One and two intragenic ...


Investigation Of The Molecular Mechanism Of Fertility Restoration In Texas Cytoplasm Maize , David Stewart Skibbe Jan 2004

Investigation Of The Molecular Mechanism Of Fertility Restoration In Texas Cytoplasm Maize , David Stewart Skibbe

Retrospective Theses and Dissertations

Cytoplasmic male sterility (cms) is a maternally inherited inability to produce viable pollen. In Texas (T)-cytoplasm maize, the combined action of two restorer of fertility genes, rfl and rfla , can overcome the male sterile phenotype. Previous research established rf2a encodes a mitochondrial aldehyde dehydrogenase (ALDH) with broad substrate specificity. This broad substrate specificity complicates determining the molecular mechanism of rf2a-mediated fertility restoration. In response, a combination of transgenic, biochemical, reverse genetic, and genomic approaches were utilized. Three additional functional maize ALDH genes (rf2b, rf2c, and rf2d) with differing substrate specificities were identified. Each ALDH gene was characterized via in ...


Identification, Characterization, And Cloning Of Arabidopsis Rhd1-4: A Udp-Glucose-4-Epimerase Mutant That Exhibits Hypersusceptibility To The Sugar Beet Cyst Nematode And Altered Root Ethylene Responses , Martin John Evers Wubben Ii Jan 2004

Identification, Characterization, And Cloning Of Arabidopsis Rhd1-4: A Udp-Glucose-4-Epimerase Mutant That Exhibits Hypersusceptibility To The Sugar Beet Cyst Nematode And Altered Root Ethylene Responses , Martin John Evers Wubben Ii

Retrospective Theses and Dissertations

Cyst nematodes (genus Heterodera) constitute an economically important class of plant pathogens that induce the formation of a complex feeding site, i.e., a syncytium, within host plant roots. Cyst nematode-induced modulations in host cell gene expression and signal transduction, via the activity of nematode esophageal gland secretions, are likely required in order to bring about syncytium formation. However, the identities of these host genes and signaling pathways targeted by the nematode remain obscure. In an effort to identify host genes pertinent to successful cyst nematode parasitism, a forward genetics mutant screen was implemented based on the Arabidopsis thaliana-Heterodera schachtii ...


The Essential Jil-1 Kinase Regulates Histone H3 Phosphorylation And Maintains Chromatin Structure In Drosophila , Weiguo Zhang Jan 2004

The Essential Jil-1 Kinase Regulates Histone H3 Phosphorylation And Maintains Chromatin Structure In Drosophila , Weiguo Zhang

Retrospective Theses and Dissertations

JIL-1 encodes a chromatin-associated tandem serine/threonine kinase in Drosophila melanogaster. JIL-1 predominantly associates with interbands on polytene chromosomes. It appears at higher levels on the X chromosome than on autosomes in males, and distributes about equally on all chromosomes in females. In addition, in males JIL-1 overlaps with the MSL (for male specific lethal) complex that specifically associates with the male X chromosome on which expression of most genes are upregulated.;We isolated JIL-1 mutants by inducing imprecise excision of an EP element inserted in JIL-1. We found that JIL-1 is required for viability of both females and males ...


The Identification, Cloning, And Characterization Of A Phospholipase C-Beta Isoform From The Sea Urchin Egg , Andre Peter Joseph Kulisz Jan 2004

The Identification, Cloning, And Characterization Of A Phospholipase C-Beta Isoform From The Sea Urchin Egg , Andre Peter Joseph Kulisz

Retrospective Theses and Dissertations

This work was the first to provide direct evidence for the presence of a PLCbeta isoform within the sea urchin egg, named suPLCbeta. The coding sequence was identified and cloned from the eggs of Lytechinus pictus and when translated, determined to have the greatest degree of homology and identity with the mammalian PLCbeta4 isoforms. This alone is a unique finding in that the presence of PLCbeta4 has only been found in the retina and specific neuronal tissues. The presence of the protein within the egg was verified using antibodies that were generated specifically against suPLCbeta, which indicate that the majority ...


Carbohydrate Partitioning And Photosynthesis In Arabidopsis Thaliana , Dan Joseph Stessman Jan 2004

Carbohydrate Partitioning And Photosynthesis In Arabidopsis Thaliana , Dan Joseph Stessman

Retrospective Theses and Dissertations

To characterize carbohydrate partitioning and photosynthesis in Arabidopsis thaliana we examined three different lines: wild type Columbia ecotype, immutans, and T-DNA knockouts of vacuolar acid invertase. Wild type plants displayed decreasing photosynthesis from the beginning of leaf expansion through senescence. Chlorophyll, total soluble protein, and expression of LhcB also declined in a similar fashion. Pulse-label feeding of 14C showed a peak flux into glucose and fructose coincident with full leaf expansion a large decrease in LhcB expression. However, flux of 14C into the different carbohydrate fractions did not reflect carbohydrate pool sizes. The conclusion was that flux into the different ...


Characterization Of Meiotic Recombination In Maize Using The A1-Sh2 Interval As A Model System , Hong Yao Jan 2004

Characterization Of Meiotic Recombination In Maize Using The A1-Sh2 Interval As A Model System , Hong Yao

Retrospective Theses and Dissertations

Meiotic recombination across the ~130--140 kb a1-sh2 interval was characterized, aiming to answer the question "Why does recombination occurs non-randomly in the maize genome?" The a1-sh2 interval contains at least four genes (a1, yz1, x1 and sh2). Initially, the breakpoints associated with 101 recombinants isolated from a stock that carries maize A1 Sh2 and a1::rdt sh2 haplotypes were physically mapped relative to sequence polymorphisms. These breakpoints are concentrated in three recombination hot spots that are located in the proximal 10% of the a1-sh2 interval. Two hot spots are genic ( a1 and yz1) and one is apparently non-genic. The x1 ...


2004 Nebraska Swine Report, Duane E. Reese Jan 2004

2004 Nebraska Swine Report, Duane E. Reese

Historical Materials from University of Nebraska-Lincoln Extension

This publications was prepared by the staff in Animal Science and cooperating Departments for use in Extension, Teaching and Research programs. It deals with the results that were done in reproduction, breeding, health, genetics, nutrition, economics and housing of swine.


Analysis Of The Lipoproteins Of Mycoplasma Hyopneumoniae, David Claude Oneal Jan 2004

Analysis Of The Lipoproteins Of Mycoplasma Hyopneumoniae, David Claude Oneal

Retrospective Theses and Dissertations

Mycoplasma hyopneumoniae causes a chronic respiratory disease in swine. It is an important component of the porcine respiratory disease complex and has been shown to enhance disease due to other pathogens. Few definitive studies of the surface architecture of M. hyopneumoniae have been reported although mycoplasmas in general abound with antigenic surface lipoproteins and other structures that contribute to disease. Hindering studies in M. hyopneumoniae are the inability to grow the organism on agar surfaces and to genetically manipulate the organism. Some monoclonal antibodies are available, but they have not been fully characterized to identify the gene product recognized. To ...