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Articles 451 - 471 of 471

Full-Text Articles in Biology

Determining The Effect Of Substitutions At Alanine 47 In Synechococcus Pcc6301 Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco), Christopher R. Salyer Jan 2006

Determining The Effect Of Substitutions At Alanine 47 In Synechococcus Pcc6301 Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco), Christopher R. Salyer

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Mutant screening and genetic selection in various organisms have shown that residues far from the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) can influence catalytic efficiency and CO2/O2 specificity. Because RubisCO catalyzes the rate-limiting step of photosynthesis, further study of these sites distant from the primary reaction center may provide the necessary information for engineering an increase in primary productivity of crop plants. In a previously described system of random mutagenesis and bioselection (Smith, 2002), the RubisCO genes from the cyanobacterium Synechococcus PCC6301, were randomly mutated and introduced into the photosynthetic bacterium Rhodobacter capsulatus. An A47T substitution resulted in a very …

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Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn Aug 2005

Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn

Biological Sciences Faculty Publications

Modeling the geographical distributions of wildlife species is important for ecology and conservation biology. Spatial autocorrelation in species distributions poses a problem for distribution modeling because it invalidates the assumption of independence among sample locations. I explored the prevalence and causes of spatial autocorrelation in data from the Breeding Bird Survey, covering the conterminous United States, using Regression Trees, Conditional Autoregressive Regressions (CAR), and the partitioning of variance. I also constructed a simulation model to investigate dispersal as a process contributing to spatial autocorrelation, and attempted to verify the connection between dispersal and spatial autocorrelation in species’ distributions in empirical …

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Evaluating Forensic Dna Evidence, Dan E. Krane, William C. Thompson Jun 2005

Evaluating Forensic Dna Evidence, Dan E. Krane, William C. Thompson

Biological Sciences Faculty Publications

No abstract provided.

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Phylogenetic Reconstruction Of Exoristinae Using Molecular Data: A Bayesian Re-Analysis, John O. Stireman Iii Feb 2005

Phylogenetic Reconstruction Of Exoristinae Using Molecular Data: A Bayesian Re-Analysis, John O. Stireman Iii

Biological Sciences Faculty Publications

A few years ago I published the results of a phylogenetic analysis of New World Exoristinae based on molecular data from two genes, 28S rDNA and Elongation Factor 1-alpha (Stireman 2002). In that study I employed parsimony, neighbor joining, and maximum likelihood inference methods to generate phylogenetic reconstructions, and explored a variety of weighting schemes and combinations of the sequence data (i.e. each gene separately and both together). The results of these analyses generally supported recent taxonomic hypotheses (e.g., Herting 1984; Wood 1987; O’Hara and Wood 2004). For example, Tachinidae and Exoristinae were reconstructed as monophyletic in most analyses, as …

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The Genetics Of Ray Pattern Variation In Caenorhabditis Briggsae, Scott Everet Baird, Cynthia R. Davidson, Justin C. Bohrer Jan 2005

The Genetics Of Ray Pattern Variation In Caenorhabditis Briggsae, Scott Everet Baird, Cynthia R. Davidson, Justin C. Bohrer

Biological Sciences Faculty Publications

Background: How does intraspecific variation relate to macroevolutionary change in morphology? This question can be addressed in species in which derived characters are present but not fixed. In rhabditid nematodes, the arrangement of the nine bilateral pairs of peripheral sense organs (rays) in tails of males is often the most highly divergent character between species. The development of ray pattern involves inputs from hometic gene expression patterns, TGFβ signalling, Wnt signalling, and other genetic pathways. In Caenorhabditis briggsae, strain-specific variation in ray pattern has provided an entrée into the evolution of ray pattern. Some strains were fixed for a derived …

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Vertebrate Gld2 Poly(A) Polymerases In The Germline And The Brain, Labib Rouhana, Liaoteng Wang, Natascha Buter, Jae Eun Kwak, Craig A. Schiltz, Tania Gonzalez, Ann E. Kelley, Charles F. Landry, Marvin Wickens Jan 2005

Vertebrate Gld2 Poly(A) Polymerases In The Germline And The Brain, Labib Rouhana, Liaoteng Wang, Natascha Buter, Jae Eun Kwak, Craig A. Schiltz, Tania Gonzalez, Ann E. Kelley, Charles F. Landry, Marvin Wickens

Biological Sciences Faculty Publications

Cytoplasmic polyadenylation is important in the control of mRNA stability and translation, and for early animal development and synaptic plasticity. Here, we focus on vertebrate poly(A) polymerases that are members of the recently described GLD2 family. We identify and characterize two closely related GLD2 proteins in Xenopus oocytes, and show that they possess PAP activity in vivo and in vitro and that they bind known polyadenylation factors and mRNAs known to receive poly(A) during development. We propose that at least two distinct polyadenylation complexes exist in Xenopus oocytes, one of which contains GLD2; the other, maskin and Pumilio. GLD2 protein …

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Evaluating Forensic Dna Evidence: Essential Elements Of A Competent Defense Review, Dan E. Krane Nov 2004

Evaluating Forensic Dna Evidence: Essential Elements Of A Competent Defense Review, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

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Evaluating Forensic Dna Evidence, Dan E. Krane Oct 2004

Evaluating Forensic Dna Evidence, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

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Forensic Dna Evidence: Collection, Mixtures, And Degradation, Dan E. Krane Oct 2004

Forensic Dna Evidence: Collection, Mixtures, And Degradation, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

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Chemical Defenses In Garlic Mustard (Alliaria Petiolata) And Their Potential Role In Species Interactions In Forest Understories, Don Cipollini Jan 2004

Chemical Defenses In Garlic Mustard (Alliaria Petiolata) And Their Potential Role In Species Interactions In Forest Understories, Don Cipollini

Biological Sciences Faculty Publications

Garlic mustard [Alliaria petiolata [(M. Bieb) Cavara & Grande; Brassicaceae] is a European native biennial herb, first recorded on Long Island, NY in the 1860s, and is expanding rapidly in northeastern and midwestern forests in the U.S. and in southern Canada. Garlic mustard flourishes in moist woodlands with moderate exposure to light, but it can grow in a diversity of other habitats. It is found in natural areas, woodlots, and along edges of agricultural fields and lawns throughout North America. Several life history traits likely contribute to the invasiveness of this species. It has a high inbreeding rate and can …

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Current Issues In Forensic Dna Profiling, Dan E. Krane Sep 2002

Current Issues In Forensic Dna Profiling, Dan E. Krane

Biological Sciences Faculty Publications

No abstract provided.

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Using Ecological Land Units In A Gap Analysis For Conservation Planning In A Southwestern Ohio Watershed, Christopher Lee Zimmerman Jan 2002

Using Ecological Land Units In A Gap Analysis For Conservation Planning In A Southwestern Ohio Watershed, Christopher Lee Zimmerman

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Gap analysis is a method to identify insufficiency in biodiversity protection. In degraded agricultural landscapes, it requires information on the past, present, and the potential natural distribution of forest vegetation to construct a comprehensive nature reserve network. Using Geographic Information Systems (GIS), I conducted a biodiversity gap analysis to assess the representation of ecological land units (ELUs) supporting forest vegetation both within and external to the current reserve network in the Lower Twin Creek Watershed (LTCW), southwestern Ohio. I used this analysis to make conservation planning recommendations to the local park district. ELUs are based on relatively stable associations of …

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Regional Variation In Recruitment Of Hemlock Seedlings And Saplings In The Upper Great Lakes, Usa, Thomas P. Rooney, Ronald J. Mccormick, Stephen L. Solheim, Donald M. Waller Aug 2000

Regional Variation In Recruitment Of Hemlock Seedlings And Saplings In The Upper Great Lakes, Usa, Thomas P. Rooney, Ronald J. Mccormick, Stephen L. Solheim, Donald M. Waller

Biological Sciences Faculty Publications

Mature eastern hemlock–northern hardwood forest cover decreased drastically in the upper Midwest following European settlement and has yet to rebound substantially. Previous studies show that stands retaining substantial hemlock canopy coverage have low hemlock seedling and sapling densities. Results from various geographically restricted studies suggest several possible mechanisms that could cause low seedling or sapling density. We examined the relative importance of these proposed mechanisms in the Southern Superior Uplands Section of the Laurentian Forest Province. We surveyed 294- m2 plots in 100 hemlock stands in northern Wisconsin and western upper Michigan to assess how these proposed mechanisms affect the …

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Periphyton Production On Wood And Sediment: Substratum-Specific Response To Laboratory And Whole-Lake Nutrient Manipulations, Yvonne Vadeboncoeur, David M. Lodge Mar 2000

Periphyton Production On Wood And Sediment: Substratum-Specific Response To Laboratory And Whole-Lake Nutrient Manipulations, Yvonne Vadeboncoeur, David M. Lodge

Biological Sciences Faculty Publications

Substratum heterogeneity is a large source of variability in periphyton production, but the influence of substratum on periphyton response to experimental manipulations is rarely measured. Using laboratory and whole-lake experiments, we compared area-specific primary production of periphyton on wood (epixylon) and sediment (epipelon), and tested whether periphyton on the 2 substrata responded differently to water-column fertilization. In the laboratory, natural periphyton assemblages on wood or sediment were exposed to 1 of 6 treatments in a fully factorial (light [250, 70, or 10 μmol m−2 s−1] × nutrient [control or + N and P]) experiment. We measured 14 …

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Exploring Cost Constraints On Stem Elongation In Plants Using Phenotypic Manipulation, Don Cipollini, Jack C. Schultz Feb 1999

Exploring Cost Constraints On Stem Elongation In Plants Using Phenotypic Manipulation, Don Cipollini, Jack C. Schultz

Biological Sciences Faculty Publications

Negative associations between individual life‐history traits of an organism are referred to as life‐history trade‐offs (Stearns 1992; Zera et al. 1998). The existence of costly trade‐offs is thought to have favored the evolution of phenotypic plasticity as a mechanism through which organisms can account for environmental heterogeneity while modulating costs and benefits incurred by fixed allocation to competing functions (Bradshaw 1965; Stearns 1992; Sultan 1995; Dudley and Schmitt 1996; Pigliucci 1996). In plants, the ability to modify stem elongation in response to environmental cues appears to be a classic form of adaptive phenotypic plasticity (Sultan 1995; Gedroc et al. 1996). …

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Top-Down Cascade From A Bitrophic Predator In An Old-Field Community, Matthew D. Moran, Thomas P. Rooney, L. E. Hurd Jan 1996

Top-Down Cascade From A Bitrophic Predator In An Old-Field Community, Matthew D. Moran, Thomas P. Rooney, L. E. Hurd

Biological Sciences Faculty Publications

We tested the hypothesis that a bitrophic (third and fourth level) arthropod predator can exert a cascading, top-down influence on other arthropods and plants in an early successional old field. First-stadium mantids, Tenodera sinensis, were added to replicated open-field plots in numbers corresponding to naturally occurring egg hatch density and allowed to remain for ≈ 2 mo. Sticky-trap dispersal barriers around both control and mantid-addition plots allowed us to monitor emigration of arthropods continuously during the experiment. Biomass of herbivores, carnivores, and plants, and abundances of arthropod taxa within plots were determined at the beginning, middle, and end of …

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Benthic-Pelagic Links: Responses Of Benthos To Water-Column Nutrient Enrichment, S. C. Blumenshine, Yvonne Vadeboncoeur, D. M. Lodge, K. L. Cottingham, S. E. Knight Sep 1994

Benthic-Pelagic Links: Responses Of Benthos To Water-Column Nutrient Enrichment, S. C. Blumenshine, Yvonne Vadeboncoeur, D. M. Lodge, K. L. Cottingham, S. E. Knight

Biological Sciences Faculty Publications

Although the responses of pelagic algae and invertebrates to gradients of nutrient enrichment are well known, less is known about the responses of benthos to such gradients or how benthic and pelagic responses may interact. We performed a 9-wk experiment in 2000-L mesocosms in the field to test for the effect of water-column nutrient enrichment on phytoplankton, algae on sediments (epipelon) and hard surfaces (plastic strips), as well as pelagic and benthic primary consumers. The experimental design consisted of 4 nutrient enrichment rates (0, 0.5, 1.0 and 2.0 μg P L-1 d-1, together with N to yield …

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Longitudinal Dynamics Of Seston Concentration And Composition In A Lake Outlet Stream, Yvonne Vadeboncoeur Jun 1994

Longitudinal Dynamics Of Seston Concentration And Composition In A Lake Outlet Stream, Yvonne Vadeboncoeur

Biological Sciences Faculty Publications

Concentrations of suspended particulate organic carbon (POC), dissolved organic carbon, bacteria, and chlorophyll a were measured in a lake outlet in western Montana, USA. Seven sites within the first 3 km downstream from the lake were sampled over 14 mo. Downstream change in concentration of each variable was tested for fit to a power function (C=aDb). Downstream changes in POC, bacteria, and chlorophyll a, sometimes fit a power function, and the value of the exponent b was positively correlated with discharge. At low discharge, a downstream decline in lake algae was accompanied by an increase in stream algae. …

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Micronuclear Genome Organization In Euplotes Crassus: A Transposonlike Element Is Removed During Macronuclear Development, Scott Everet Baird, Gina M. Fino, Susan L. Tausta, Lawrence A. Klobutcher Sep 1989

Micronuclear Genome Organization In Euplotes Crassus: A Transposonlike Element Is Removed During Macronuclear Development, Scott Everet Baird, Gina M. Fino, Susan L. Tausta, Lawrence A. Klobutcher

Biological Sciences Faculty Publications

After mating, hypotrichous ciliated protozoa transform a set of their micronuclear chromosomes into thousands of short, linear DNA molecules that form the macronuclear genome. To examine micronuclear genome organization in the hypotrich Euplotes crassus, we have analyzed two cloned segments of micronuclear DNA as well as the macronuclear DNA molecules that are derived from them. E. crassus was found to display a number of features characteristic of other hypotrich genomes, including (i) clustering and close spacing of the precursors of macronuclear DNA molecules, (ii) the frequent occurrence of internal eliminated sequences within macronuclear precursors, (iii) overlapping macronuclear precursors, (iv) lack …

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Characterization Of Chromosome Fragmentation In Two Protozoans And Identification Of A Candidate Fragmentation Sequence In Euplotes Crassus, Scott Everet Baird, Lawrence A. Klobutcher Jan 1989

Characterization Of Chromosome Fragmentation In Two Protozoans And Identification Of A Candidate Fragmentation Sequence In Euplotes Crassus, Scott Everet Baird, Lawrence A. Klobutcher

Biological Sciences Faculty Publications

Following the sexual cycle, hypotrichous ciliated protozoans fragment a set of their micronuclear chromosomes to generate the thousands of short, linear DNA molecules present in the transcriptionally active macronucleus. We have used a hybrid selection procedure to examine macronuclear DNA molecules for subtelomeric length heterogeneity to determine whether chromosome fragmentation occurs at unique or multiple sites. The results suggest that multiple, but closely spaced, chromosome fragmentation sites are used by Oxytricha nova. In contrast, Euplotes crassus uses unique chromosome fragmentation sites in a reproducible manner to generate the ends of macronuclear DNA molecules. Additional studies compared DNA sequences in …

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Botany Sketchbook - Orville Wright, Orville Wright Jan 1887

Botany Sketchbook - Orville Wright, Orville Wright

Wright Family School Items

A botany notebook that belonged to Orville Wright filled with drawings and observations about flowers and other plants sometime between 1887 and 1888.

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