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In Vivo Dose-Response Of Insects To Hz-2v Infection, John P. Burand, Christopher P. Rallis Dec 2004

In Vivo Dose-Response Of Insects To Hz-2v Infection, John P. Burand, Christopher P. Rallis

John Burand

Background Hz-2V infection of female Helicoverpa zea moths is manifested as insects that are either sterile "agonadal" individuals with malformed reproductive tissues or fertile asymptomatic carriers which are capable of transmitting virus on to their progeny. Virus infected progeny arising from eggs laid by asymptomatic carrier females may themselves be either sterile agonadals or asymptomatic carriers. Results By injecting virus into female moths, a correlation was established between virus doses administered to the females and the levels of resulting asymptomatic and sterile progeny. Conclusions The results of these experiments indicate that high virus doses produced a higher level of agonadal ...


In Vivo Dose-Response Of Insects To Hz-2v Infection, John Burand, Christopher Rallis Dec 2004

In Vivo Dose-Response Of Insects To Hz-2v Infection, John Burand, Christopher Rallis

Microbiology Department Faculty Publication Series

Background Hz-2V infection of female Helicoverpa zea moths is manifested as insects that are either sterile "agonadal" individuals with malformed reproductive tissues or fertile asymptomatic carriers which are capable of transmitting virus on to their progeny. Virus infected progeny arising from eggs laid by asymptomatic carrier females may themselves be either sterile agonadals or asymptomatic carriers. Results By injecting virus into female moths, a correlation was established between virus doses administered to the females and the levels of resulting asymptomatic and sterile progeny. Conclusions The results of these experiments indicate that high virus doses produced a higher level of agonadal ...


Allele Specific Synthetic Lethality Between Pric And Dnaats Alleles At The Permissive Temperature Of 30°C In E. Coli K-12, Steven Sandler, Tania Hinds Dec 2004

Allele Specific Synthetic Lethality Between Pric And Dnaats Alleles At The Permissive Temperature Of 30°C In E. Coli K-12, Steven Sandler, Tania Hinds

Steven Sandler

Background DnaA is an essential protein in the regulation and initiation of DNA replication in many bacteria. It forms a protein-DNA complex at oriC to which DnaC loads DnaB. DNA replication forks initiated at oriC by DnaA can collapse on route to the terminus for a variety of reasons. PriA, PriB, PriC, DnaT, Rep and DnaC form multiple pathways to restart repaired replication forks. DnaC809 and dnaC809,820 are suppressors of priA2::kan mutant phenotypes. The former requires PriC and Rep while the latter is independent of them. RnhA339::cat mutations allow DnaA-independent initiation of DNA replication. Results It is ...


In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley Dec 2004

In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley

Kelly Nevin

In order to determine whether the metabolic state of Geobacteraceae involved in bioremediation of subsurface sediments might be inferred from levels of mRNA for key genes, in situ expression of nifD, a highly conserved gene involved in nitrogen fixation, was investigated. When Geobacter sulfurreducens was grown without a source of fixed nitrogen in chemostats with acetate provided as the limiting electron donor and Fe(III) as the electron acceptor, levels of nifD transcripts were 4 to 5 orders of magnitude higher than in chemostat cultures provided with ammonium. In contrast, the number of transcripts of recA and the 16S rRNA ...


Evidence For Involvement Of An Electron Shuttle In Electricity Generation By Geothrix Fermentans, Daiel R. Bond, Derek Lovley Nov 2004

Evidence For Involvement Of An Electron Shuttle In Electricity Generation By Geothrix Fermentans, Daiel R. Bond, Derek Lovley

Derek Lovley

In experiments performed using graphite electrodes poised by a potentiostat (+200 mV versus Ag/AgCl) or in a microbial fuel cell (with oxygen as the electron acceptor), the Fe(III)-reducing organism Geothrix fermentans conserved energy to support growth by coupling the complete oxidation of acetate to reduction of a graphite electrode. Other organic compounds, such as lactate, malate, propionate, and succinate as well as components of peptone and yeast extract, were utilized for electricity production. However, electrical characteristics and the results of shuttling assays indicated that unlike previously described electrode-reducing microorganisms, G. fermentans produced a compound that promoted electrode ...


The Unpredictable Past Of Plasmodium Vivax Revealed In Its Genome, Stephen M. Rich Oct 2004

The Unpredictable Past Of Plasmodium Vivax Revealed In Its Genome, Stephen M. Rich

Stephen M. Rich

Until quite recently, very little information has been available about the genome content and structure of parasitic protozoa. This inadequacy has been rectified by the advent of high-throughput strategies that permit sequencing of whole genomes and enhanced computational capacities that render this information tractable. The current list of complete or near-complete genomes includes some of the greatest scourges of humans and their domesticated companions. Among these miscreants are several members of the genus Plasmodium, the agents of malaria. Scores of species of Plasmodium have been described and comprise pathogens of every major group of terrestrial vertebrates. At present, no less ...


Resistance Of Solid-Phase U(Vi) To Microbial Reduction During In Situ Bioremediation Of Uranium-Contaminated Groundwater, Irene Ortiz-Bernad, Robert T. Anderson, Helen A. Vrionis, Derek Lovley Jul 2004

Resistance Of Solid-Phase U(Vi) To Microbial Reduction During In Situ Bioremediation Of Uranium-Contaminated Groundwater, Irene Ortiz-Bernad, Robert T. Anderson, Helen A. Vrionis, Derek Lovley

Derek Lovley

Speciation of solid-phase uranium in uranium-contaminated subsurface sediments undergoing uranium bioremediation demonstrated that although microbial reduction of soluble U(VI) readily immobilized uranium as U(IV), a substantial portion of the U(VI) in the aquifer was strongly associated with the sediments and was not microbially reducible. These results have important implications for in situ uranium bioremediation strategies.


In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley Jul 2004

In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley

Derek Lovley

In order to determine whether the metabolic state of Geobacteraceae involved in bioremediation of subsurface sediments might be inferred from levels of mRNA for key genes, in situ expression of nifD, a highly conserved gene involved in nitrogen fixation, was investigated. When Geobacter sulfurreducens was grown without a source of fixed nitrogen in chemostats with acetate provided as the limiting electron donor and Fe(III) as the electron acceptor, levels of nifD transcripts were 4 to 5 orders of magnitude higher than in chemostat cultures provided with ammonium. In contrast, the number of transcripts of recA and the 16S rRNA ...


Attracting Antagonists: Does Floral Nectar Increase Leaf Herbivory?, Lynn Adler, Judith L. Bronstein Jun 2004

Attracting Antagonists: Does Floral Nectar Increase Leaf Herbivory?, Lynn Adler, Judith L. Bronstein

Lynn Adler

Traits that are attractive to mutualists may also attract antagonists, resulting in conflicting selection pressures. Here we develop the idea that increased floral nectar production can, in some cases, increase herbivory. In these situations, selection for increased nectar production to attract pollinators may be constrained by a linked cost of herbivore attraction. In support of this hypothesis, we report that experimentally supplementing nectar rewards in Datura stramonium led to increased oviposition by Manduca sexta, a sphingid moth that pollinates flowers, but whose larvae feed on leaf tissue. We speculate that nectar composition may provide information about plant nutritional status or ...


Direct Correlation Between Rates Of Anaerobic Respiration And Levels Of Mrna For Key Respiratory Genees In Geobacter Sulfurreducens, Abraham Esteve-Núñez, Ching Leang, Kuk-Jeong Chin, Derek Lovley May 2004

Direct Correlation Between Rates Of Anaerobic Respiration And Levels Of Mrna For Key Respiratory Genees In Geobacter Sulfurreducens, Abraham Esteve-Núñez, Ching Leang, Kuk-Jeong Chin, Derek Lovley

Derek Lovley

The predominance of Geobacter species in environments in which Fe(III) reduction is important has suggested that Fe(III) reduction rates might be estimated in Geobacter-dominated environments by assessing in situ activity with molecular techniques. To determine whether mRNA levels of key respiratory genes might be correlated with respiration rates in Geobacter sulfurreducens, studies were conducted with fumarate as the electron acceptor and acetate as the limiting electron donor in anaerobic continuous cultures. Levels of mRNA for a fumarate reductase gene, frdA, quantified by real-time reverse transcription-PCR were directly correlated with fumarate reduction rates. In similar studies with Fe(III ...


Synergistic And Antagonistic Roles Of The Sonic Hedgehog N- And C-Terminal Lipids, Jianchi Feng, Bryan White, Oksana V. Tyurina, Burcu Guner, Theresa Larson, Hae Young Lee, Rolf O. Karlstrom, Jhumku D. Kohtz May 2004

Synergistic And Antagonistic Roles Of The Sonic Hedgehog N- And C-Terminal Lipids, Jianchi Feng, Bryan White, Oksana V. Tyurina, Burcu Guner, Theresa Larson, Hae Young Lee, Rolf O. Karlstrom, Jhumku D. Kohtz

Rolf O Karlstrom

The Shh protein contains both N-terminal and C-terminal lipids. The functional redundancy of these lipid moieties is presently unclear. Here, we compare the relative roles of the N- and C-terminal lipids in early rat striatal neuronal differentiation, membrane association and multimerization, and ventralizing activity in the zebrafish forebrain. We show that these lipid act synergistically in cell tethering and the formation of a large (L) multimer (669 kDa). However, the C-terminal lipid antagonizes the rat striatal neuronal differentiation-inducing activity of the N-terminal lipid. In addition, multimerization is required but not sufficient for the differentiation-inducing activity. Based on the presence of ...


A Regulatory Code For Neurogenic Gene Expression In The Drosophila Embryo, Michele Markstein, Robert Zinzen, Peter Markstein, Ka Ping Yee, Albert Erives, Angela Stathopoulos, Michael Levine May 2004

A Regulatory Code For Neurogenic Gene Expression In The Drosophila Embryo, Michele Markstein, Robert Zinzen, Peter Markstein, Ka Ping Yee, Albert Erives, Angela Stathopoulos, Michael Levine

Michele Markstein

Bioinformatics methods have identified enhancers that mediate restricted expression in the Drosophila embryo. However, only a small fraction of the predicted enhancers actually work when tested in vivo. In the present study, co-regulated neurogenic enhancers that are activated by intermediate levels of the Dorsal regulatory gradient are shown to contain several shared sequence motifs. These motifs permitted the identification of new neurogenic enhancers with high precision: five out of seven predicted enhancers direct restricted expression within ventral regions of the neurogenic ectoderm. Mutations in some of the shared motifs disrupt enhancer function, and evidence is presented that the Twist and ...


Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley May 2004

Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley

Kelly Nevin

A facultatively anaerobic, acid-resistant bacterium, designated strain FRCl, was isolated from a low-pH, nitrate- and U(VI)-contaminated subsurface sediment at site FW-024 at the Natural and Accelerated Bioremediation Research Field Research Center in Oak Ridge, Tenn. Strain FRCl was enriched at pH 4.5 in minimal medium with nitrate as the electron acceptor, hydrogen as the electron donor, and acetate as the carbon source. Clones with 16S ribosomal DNA (rDNA) sequences identical to the sequence of strain FRCl were also detected in a U(VI)-reducing enrichment culture derived from the same sediment. Cells of strain FRCl were gram-negative ...


Expression Of Haper1 And Habmal1 In Syrian Hamsters: Heterogeneity Of Transcripts And Oscillations In The Periphery, Eric L. Bittman, Yanhong Tong, Hongnian Guo, Judy Mckinley Brewer, Alexamder S. Bois Apr 2004

Expression Of Haper1 And Habmal1 In Syrian Hamsters: Heterogeneity Of Transcripts And Oscillations In The Periphery, Eric L. Bittman, Yanhong Tong, Hongnian Guo, Judy Mckinley Brewer, Alexamder S. Bois

Eric L. Bittman

The molecular biology of circadian rhythms has been extensively studied in mice, and the widespread expression of canonical circadian clock genes in peripheral organs is well established in this species. In contrast, much less information about the peripheral expression of haPer1, haPer2, and haBmal1 is available in Syrian hamsters despite the fact that this species is widely used for studies of circadian organization and photoperiodic responses. Furthermore, examination of oscillating expression of these genes in mouse testis has generated discrepant results, and little is known about gonadal expression of haPer1 and haBmal1 or their environmental control. To address these questions ...


Maca, A Diheme C-Type Cytochrome Involved In Fe(Iii) Reduction By Geobacter Sulfurreducens, Jessica E. Butler, Franz Kaufmann, Cinthia Núñez, Maddalena V. Coppi, Derek Lovley Feb 2004

Maca, A Diheme C-Type Cytochrome Involved In Fe(Iii) Reduction By Geobacter Sulfurreducens, Jessica E. Butler, Franz Kaufmann, Cinthia Núñez, Maddalena V. Coppi, Derek Lovley

Derek Lovley

A 36-kDa diheme c-type cytochrome abundant in Fe(III)-respiring Geobacter sulfurreducens, designated MacA, was more highly expressed during growth with Fe(III) as the electron acceptor than with fumarate. Although MacA has homology to proteins with in vitro peroxidase activity, deletion of macA had no impact on response to oxidative stress. However, the capacity for Fe(III) reduction was greatly diminished, indicating that MacA, which is predicted to be localized in the periplasm, is a key intermediate in electron transfer to Fe(III).


Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley Feb 2004

Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley

Derek Lovley

A facultatively anaerobic, acid-resistant bacterium, designated strain FRCl, was isolated from a low-pH, nitrate- and U(VI)-contaminated subsurface sediment at site FW-024 at the Natural and Accelerated Bioremediation Research Field Research Center in Oak Ridge, Tenn. Strain FRCl was enriched at pH 4.5 in minimal medium with nitrate as the electron acceptor, hydrogen as the electron donor, and acetate as the carbon source. Clones with 16S ribosomal DNA (rDNA) sequences identical to the sequence of strain FRCl were also detected in a U(VI)-reducing enrichment culture derived from the same sediment. Cells of strain FRCl were gram-negative ...


Vanadium Respiration By Geobacter Metallireducens: Novel Strategy For In Situ Removal Of Vanadium From Groundwater, Irene Ortiz-Bernad, Robert T. Anderson, Helen A. Vrionis, Derek Lovley Feb 2004

Vanadium Respiration By Geobacter Metallireducens: Novel Strategy For In Situ Removal Of Vanadium From Groundwater, Irene Ortiz-Bernad, Robert T. Anderson, Helen A. Vrionis, Derek Lovley

Derek Lovley

Vanadium can be an important contaminant in groundwaters impacted by mining activities. In order to determine if microorganisms of the Geobacteraceae, the predominant dissimilatory metal reducers in many subsurface environments, were capable of reducing vanadium(V), Geobacter metallireducens was inoculated into a medium in which acetate was the electron donor and vanadium(V) was the sole electron acceptor. Reduction of vanadium(V) resulted in the production of vanadium(IV), which subsequently precipitated. Reduction of vanadium(V) was associated with cell growth with a generation time of 15 h. No vanadium(V) was reduced and no precipitate was formed in heat-killed ...


Identification Of An Uptake Hydrogenase Required For Hydrogen-Dependant Reduction Of Fe(Iii) And Other Electron Acceptors By Geobacter Sulfurreducens, Maddalena V. Coppi, Regina A. O'Neil, Derek Lovley Feb 2004

Identification Of An Uptake Hydrogenase Required For Hydrogen-Dependant Reduction Of Fe(Iii) And Other Electron Acceptors By Geobacter Sulfurreducens, Maddalena V. Coppi, Regina A. O'Neil, Derek Lovley

Derek Lovley

Geobacter sulfurreducens, a representative of the family Geobacteraceae that predominates in Fe(III)-reducing subsurface environments, can grow by coupling the oxidation of hydrogen to the reduction of a variety of electron acceptors, including Fe(III), fumarate, and quinones. An examination of the G. sulfurreducens genome revealed two operons, hya and hyb, which appeared to encode periplasmically oriented respiratory uptake hydrogenases. In order to assess the roles of these two enzymes in hydrogen-dependent growth, Hya- and Hyb-deficient mutants were generated by gene replacement. Hyb was found to be required for hydrogen-dependent reduction of Fe(III), anthraquinone-2,6-disulfonate, and fumarate by ...


Cranberry Irrigation Management, Hilary A. Sandler, Carolyn J. Demoranville, Bruce Lampinen Feb 2004

Cranberry Irrigation Management, Hilary A. Sandler, Carolyn J. Demoranville, Bruce Lampinen

Cranberry Station Fact Sheets

No abstract provided.


Preferential Reduction Of Fe(Iii) Over Fumarate By Geobacter Sulfurreducens, Abraham Esteve-Núñez, Cinthia Núñez, Derek Lovley Jan 2004

Preferential Reduction Of Fe(Iii) Over Fumarate By Geobacter Sulfurreducens, Abraham Esteve-Núñez, Cinthia Núñez, Derek Lovley

Derek Lovley

The presence of Fe(III), but not that of Fe(II), resulted in ca. 20-fold-lower levels of mRNA for fumarate reductase, inhibiting fumarate reduction and favoring utilization of fumarate as an electron donor in chemostat cultures of Geobacter sulfurreducens, despite the fact that growth yield with fumarate was 3-fold higher than with Fe(III).


Immunity Regulatory Dnas Share Common Organizational Features In Drosophila, Kate Senger, Grant W. Armstrong, William J. Rowell, Jennifer M. Kwan, Michele Markstein, Michael Levine Jan 2004

Immunity Regulatory Dnas Share Common Organizational Features In Drosophila, Kate Senger, Grant W. Armstrong, William J. Rowell, Jennifer M. Kwan, Michele Markstein, Michael Levine

Michele Markstein

Infection results in the rapid activation of immunity genes in the Drosophila fat body. Two classes of transcription factors have been implicated in this process: the REL-containing proteins, Dorsal, Dif, and Relish, and the GATA factor Serpent. Here we present evidence that REL-GATA synergy plays a pervasive role in the immune response. SELEX assays identified consensus binding sites that permitted the characterization of several immunity regulatory DNAs. The distribution of REL and GATA sites within these DNAs suggests that most or all fat-specific immunity genes contain a common organization of regulatory elements: closely linked REL and GATA binding sites positioned ...


The Dual Role Of Floral Traits: Pollinator Attraction And Plant Defense, Rebecca E. Irwin, Lynn Adler, Alison K. Brody Jan 2004

The Dual Role Of Floral Traits: Pollinator Attraction And Plant Defense, Rebecca E. Irwin, Lynn Adler, Alison K. Brody

Lynn Adler

Plants are under siege from a diversity of enemies that consume both leaf and floral parts. Plants resist damage to leaves in a variety of ways, and we now have a rich literature documenting how plants defend themselves against herbivore attack. In contrast, the mechanisms by which plants resist enemies that consume floral parts or resources are much less known, even though damage to floral tissue usually has tighter links to plant fitness than damage to leaf tissue. Many plants experience nectar robbing, whereby floral visitors remove nectar from flowers, often without pollinating. Nectar robbers can reduce plant fitness to ...


Heterogeneous Evolutionary Processes Affect R Gene Diversity In Natural Populations Of Solanum Pimpinellifolium, Ana Lucia Caicedo, B. A. Schaal Jan 2004

Heterogeneous Evolutionary Processes Affect R Gene Diversity In Natural Populations Of Solanum Pimpinellifolium, Ana Lucia Caicedo, B. A. Schaal

Ana Lucia Caicedo

Resistance (R) genes of plants are responsible for pathogen recognition and encode proteins that trigger a cascade of responses when a pathogen invades a plant. R genes are assumed to be under strong selection, but there is limited knowledge of the processes affecting R gene diversity in the wild. In this study, DNA sequence variation of Cf-2 homologs was surveyed in populations of Solanum pimpinellifolium, a wild relative of the cultivated tomato. The Cf-2 locus is involved in resistance to strains of the fungus Cladosporium fulvum. At least 26 different Cf-2 homologs were detected in natural populations of S. pimpinellifolium ...


Managing The Wild: Should Stewards Be Pilots?, Peter Alpert Jan 2004

Managing The Wild: Should Stewards Be Pilots?, Peter Alpert

Peter Alpert

No abstract provided.


Disorganization Of Cortical Microtubules Stimulates Tangential Expansion And Reduces The Uniformity Of Cellulose Microfibril Alignment Among Cells In The Root Of Arabidopsis Thaliana, Tobias Baskin, G.T.S. Beemster, J.E. Judy-March, F. Marga Jan 2004

Disorganization Of Cortical Microtubules Stimulates Tangential Expansion And Reduces The Uniformity Of Cellulose Microfibril Alignment Among Cells In The Root Of Arabidopsis Thaliana, Tobias Baskin, G.T.S. Beemster, J.E. Judy-March, F. Marga

Tobias Baskin

To test the role of cortical microtubules in aligning cellulose microfibrils and controlling anisotropic expansion, we exposed Arabidopsis thaliana roots to moderate levels of the microtubule inhibitor, oryzalin. After 2 d of treatment, roots grow at approximately steady state. At that time, the spatial profiles of relative expansion rate in length and diameter were quantified, and roots were cryofixed, freeze-substituted, embedded in plastic, and sectioned. The angular distribution of microtubules as a function of distance from the tip was quantified from antitubulin immunofluorescence images. In alternate sections, the overall amount of alignment among microfibrils and their mean orientation as a ...


Yellow Stripe1. Expanded Roles For The Maize Iron-Phytosiderophore Transporter, Elsbeth Walker, L. A. Roberts, A. J. Pierson, Z Panaviene Jan 2004

Yellow Stripe1. Expanded Roles For The Maize Iron-Phytosiderophore Transporter, Elsbeth Walker, L. A. Roberts, A. J. Pierson, Z Panaviene

Elsbeth Walker

Graminaceous monocots, including most of the world's staple grains (i.e. rice, corn, and wheat) use a chelation strategy (Strategy II) for primary acquisition of iron from the soil. Strategy II plants secrete phytosiderophores (PS), compounds of the mugineic acid family that form stable Fe(III) chelates in soil. Uptake of iron-PS chelates, which occurs through specific transporters at the root surface, thus represents the primary route of iron entry into Strategy II plants. The gene Yellow stripe1 (Ys1) encodes the Fe(III)-PS transporter of maize (Zea mays). Here the physiological functions performed by maize YS1 were further ...


Extrapair Paternity Increases Variability In Male Reproductive Success In The Chestnut-Sided Warbler (Dendroica Pensylvanica), A Socially Monogamous Songbirds, Bruce Byers Jan 2004

Extrapair Paternity Increases Variability In Male Reproductive Success In The Chestnut-Sided Warbler (Dendroica Pensylvanica), A Socially Monogamous Songbirds, Bruce Byers

Bruce Byers

A monogamous mating system that includes extrapair fertilization can potentially generate higher variability in male reproductive success than monogamy without extrapair fertilization. That increased variability could provide a correspondingly higher opportunity for sexual selection and, thus, for the origin and persistence of sexual dimorphism in monogamous species. To determine whether extrapair fertilization enhanced the opportunity for sexual selection in a sexually dimorphic, monogamous bird species, we used microsatellite DNA typing to assess the prevalence of extrapair fertilization and its effect on variation in male reproductive success in a population of Chestnut-sided Warblers (Dendroica pensylvanica). We found that the level of ...


Epistatic Interaction Between The Arabidopsis Fri And Flc Flowering Time Genes Generates A Latitudinal Cline In A Life History Trait, Ana Lucia Caicedo, J. R. Stinchcombe, K. M. Olsen, J Schmitt, M. D. Purugganan Jan 2004

Epistatic Interaction Between The Arabidopsis Fri And Flc Flowering Time Genes Generates A Latitudinal Cline In A Life History Trait, Ana Lucia Caicedo, J. R. Stinchcombe, K. M. Olsen, J Schmitt, M. D. Purugganan

Ana Lucia Caicedo

Epistatic gene interactions are believed to be a major factor in the genetic architecture of evolutionary diversification. In Arabidopsis thaliana, the FRI and FLC genes mechanistically interact to control flowering time, and here we show that this epistatic interaction also contributes to a latitudinal cline in this life history trait within the species. Two major FLC haplogroups (FLCA and FLCB ) are associated with flowering time variation in A. thaliana in field conditions, but only in the presence of putatively functional FRI alleles. Significant differences in latitudinal distribution of FLC haplogroups in Eurasia and North Africa also depend on the FRI ...


Phosphorus For Bearing Cranberries In North America, Teryl Roper, Joan Davenport, Carolyn J. Demoranville, Sebastien Marchand, Art Poole, Kim Patten Jan 2004

Phosphorus For Bearing Cranberries In North America, Teryl Roper, Joan Davenport, Carolyn J. Demoranville, Sebastien Marchand, Art Poole, Kim Patten

Cranberry Station Fact Sheets

No abstract provided.


Disorganization Of Cortical Microtubules Stimulates Tangential Expansion And Reduces The Uniformity Of Cellulose Microfibril Alignment Among Cells In The Root Of Arabidopsis, Ti Baskin, Gts Beemster, Je Judy-March, F Marga Jan 2004

Disorganization Of Cortical Microtubules Stimulates Tangential Expansion And Reduces The Uniformity Of Cellulose Microfibril Alignment Among Cells In The Root Of Arabidopsis, Ti Baskin, Gts Beemster, Je Judy-March, F Marga

Biology Department Faculty Publication Series

No abstract provided.