Biology Commons^™

Estimating The Latitudinal Origins Of Migratory Birds Using Hydrogen And Sulfur Stable Isotopes In Feathers: Influence Of Marine Prey Base, Casey A. Lott, Timothy D. Meehan, Julie A. Heath

Julie Heath

Hydrogen stable isotope analysis of feathers is an important tool for estimating the natal or breeding latitudes of nearctic-neotropical migratory birds. This method is based on the latitudinal variation of hydrogen stable isotope ratios in precipitation in North America (iDp) and the inheritance of this variation in newly formed feathers (iDf). We hypothesized that the typically strong relationship between iDp and iDf would be decoupled in birds that forage in marine food webs because marine waters have relatively high iD values compared to iD values for local precipitation. Birds that forage on marine prey bases should also have feathers with …

Coastal Habitat Use By Wood Storks During The Non-Breeding Season, A. L. Bryan Jr., Karen F. Gaines, C. S. Eldridge

Karen F. Gaines

We documented roosting and foraging habitat use by Wood Storks during the post-breeding season in the coastal zone of Georgia from 1994-1998. Larger, more persistent aggregations of roosting storks typically oc- curred in enclosed wetlands on large estuarine islands. Smaller, more ephemeral aggregations tended to occur on salt marsh/upland ecotones, where storks appeared to be waiting for local conditions (tide levels) to become suit- able for foraging. Examination of habitat types within a 2-km radius of the larger (mean > 10 storks/survey) vs. smaller (mean <10 storks/survey) roosts showed that surrounding habitat structure, including those used for for- aging, were similar. Foraging storks typically fed in close proximity (median = 0.5 km) to large roosts, much closer than storks using coastal wetlands during the breeding season. Tidal creeks were used almost exclusively as foraging habitat (92%). Storks and other wading birds were almost always present when the study bird arrived. The foraging patterns of study birds and four storks carrying radios suggested that storks often used the same foraging sites and/ or marsh systems in the non-breeding season. Coastal Wood Storks apparently selected roosting sites based on the presence of conspecifics, abundant local prey, or possibly as shelter from adverse weather conditions

Whole-Genome Analysis Of Dorsal-Ventral Patterning In The Drosophila Embryo, Angelike Stathopoulos, Madeleine Van Drenth, Albert Erives, Michele Markstein, Michael Levine

Michele Markstein

The maternal Dorsal regulatory gradient initiates the differentiation of several tissues in the early Drosophila embryo. Whole-genome microarray assays identified as many as 40 new Dorsal target genes, which encode a broad spectrum of cell signaling proteins and transcription factors. Evidence is presented that a tissue-specific form of the NF-Y transcription complex is essential for the activation of gene expression in the mesoderm. Tissue-specific enhancers were identified for new Dorsal target genes, and bioinformatics methods identified conserved cis-regulatory elements for coordinately regulated genes that respond to similar thresholds of the Dorsal gradient. The new Dorsal target genes and enhancers represent …

Decoding Cis-Regulatory Dnas In The Drosophila Genome, Michele Markstein, Michael Levine

Michele Markstein

Cis-regulatory DNAs control the timing and sites of gene expression during metazoan development. Changes in gene expression are responsible for the morphological diversification of metazoan body plans. However, traditional methods for the identification and characterization of cis-regulatory DNAs are tedious. During the past year, computational methods have been used to identify novel cis-DNAs within the entire Drosophila genome. These methods change the way that cis-DNAs will be analyzed in future studies and offer the promise of unraveling complex gene networks.

A Mathematical Model Of Bacterial Aerotaxis, Borbala Mazzag, Alex Mogilner

Borbala Mazzag

No abstract provided.

No Difference Found In Ribosomal Dna Sequences From Physiologically Diverse Clones Of Karenia Brevis (Dinophyceae) From The Gulf Of Mexico, Torstein Tengs

Dr. Torstein Tengs

Maximum growth rate and toxin content were significantly different among five strains of Karenia brevis isolated from Texas and Florida when grown under identical culture conditions. Sequence analysis of the 18S rRNA gene and internal transcribed spacer (ITS) regions revealed, however, that all five strains were identical. Consequently, a clear genetic basis for physiological variability among various geographical isolates of K. brevis from the Gulf of Mexico could not be assessed using these genetic markers. Both the ITS and 18S rRNA regions may be useful in species-specific probe selection. At the intra-specific level, however, an alternative marker will be needed …

Caudal Spotting In The Beacon Fish (Hemigrammus Ocellifer Characidae), Jack Frankel

Jack Frankel

Role Of A Heterotrimeric G Protein In Regulation Of Arabidopsis Seed Germination, Hemayet Ullah, Jin-Gui Chen, Shucai Wang, Alan M. Jones

Hemayet Ullah

Survival Of And Herbivore Damage To A Cohort Of Quercus Rubra Planted Across A Forest-Old-Field Edge, Scott J. Meiners, Matthew J. Matinkovic

Scott J. Meiners

Forest edges are known to affect plant community composition and habitat use by animals. However, the direct influence of edges in determining patterns of tree regeneration is poorly understood. Survival of and herbivore damage to Quercus ruln-a seedlings were experimentally determined for seedlings planted across a forest--old-field edge gradient. Seedling survival was lowest inside the forest ( 1%), intermediate at the edge (25%) and highest within the old-field portion of the gradient (49%). Deer herbivory decreased with increasing distance into the old field. Seedling survival increased under Rosa multiflora and decreased in plots with mammalian herbivory. Seedling height was significantly …

The Nmda Receptor M3 Segment Is A Conserved Transduction Element Coupling Ligand Binding To Channel Opening, Kevin S. Jones, Hendrika M A Vandongen, Antonius M. Vandongen

Kevin Jones

Captive Double-Crested Cormorant Phalacrocorax Auritus Predation On Channel Catfish Ictalurus Punctatus Fingerlings And Its Influence On Single-Batch Cropping Production, Brian S. Dorr

Brian S Dorr

Abstract.-We studied the effect of captive double-crested cormorant Phalacrocorax auritus predation on channel catfish Ictalurus punctatus inventories from research ponds with and without alternative prey during the years 1998-2000. In 1998, predation by two groups of captive cormorants on ponds without alternative prey produced inventory reductions relative to a control pond that were equivalent to 10.2 (516 g) and I 0.5 (608 g) catfish/bird per d. In 1999 and 2000 individual cormorants foraging on 0.02-ha pond halves for I 0 d (500 cormorant d/ha) stocked with both catfish and golden shiners Notemigonus crysoleucas produced inventory reductions at harvest (7.5 mo …

Spiroplasmas: Evolution, Adaptation And Diversity, Gail E. Gasparich

Gail Gasparich

Costs Of Reproduction In The Terrestrial Isopod Porcellio Laevis Latreille (Isopoda: Oniscidea): Brood-Bearing And Locomotion, Scott Kight

Scott Kight

Biological Implications Of The Weibull And Gompertz Models Of Aging, Robert Ricklefs, Alex Scheuerlein

Robert Ricklefs

Genome-Wide Analysis Of Clustered Dorsal Binding Sites Identifies Putative Target Genes In The Drosophila Embryo, Michele Markstein, Peter Markstein, Vicky Markstein, Michael Levine

Michele Markstein

Metazoan genomes contain vast tracts of cis-regulatory DNA that have been identified typically through tedious functional assays. As a result, it has not been possible to uncover a cis-regulatory code that links primary DNA sequences to gene expression patterns. In an initial effort to determine whether coordinately regulated genes share a common “grammar,” we have examined the distribution of Dorsal recognition sequences in the Drosophila genome. Dorsal is one of the best-characterized sequence-specific transcription factors in Drosophila. The homeobox gene zerknullt (zen) is repressed directly by Dorsal, and this repression is mediated by a 600-bp silencer, the ventral repression element …

Using Raccoons As An Indicator Species For Metal Accumulation Across Trophic Accumulation Across Trophic Levels: A Stable Isotope Approach, Karen F. Gaines, Christhopher S. Romanek, C. Shane Boring, Christine G. Lord, Michael Gochfeld, Joanna Burger

Karen F. Gaines

: The fact that raccoons (Procyon lotor) are an opportunistic omnivore has severely complicated interpreta- tions of contaminant uptake patterns due to the inability to determine the trophic position an individual occupies. Moreover, few studies have examined the relationships between heavy metal bioaccumulation and trophic struc- ture, especially in the terrestrial environment. In this study, the stable isotopes of nitrogen were used to charac- terize the feeding habits of the raccoon at the population level and to determine whether metal burden was relat- ed to trophic feeding structure within a welldefined ecosystem. Raccoon populations were isotopically distinct, and significant positive …

Scirpus Ancistrochaetus (Cyperaceae): First Record In Canada, Stuart G. Hay, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.

Probability Of Tree Seedling Establishment Changes Across A Forest–Old Field Edge Gradient, Scott J. Meiners, Steward T.A. Pickett, Steven N. Handel

Scott J. Meiners

Forest edges affect many aspects of plant communities, causing changes in microclimate, species composition, and community structure. However, the direct role of edges in regulating forest regeneration is relatively unknown. The pattern of tree establishment across a forest–old field edge was experimentally examined to determine the response of three tree species to the edge gradient. We placed 100 1-m2 plots in a 90 3 90 m grid that began 30 m inside the forest, extended across the edge, and ended at 60 m into the old field. Into each plot, we planted seeds of Acer rubrum, Acer saccharum, and Quercus …

Problems With Developmental Stability In Two Rodent Species From Chornobyl, Taras K. Oleksyk, Michael H. Smith, Sergiy P. Gashchak, James M. Novak, James R. Purdue

James M. Novak

Changes in developmental patterns are some of the most important effects that may be observed at radioactively contaminated sites like those at Chornobyl. Developmental instability may arise from the interactions between an organism's genotype and its environment and be manifested as deviant morphology. Fluctuating asymmetry (FA) is a measure of deviations from the expected bilateral symmetry of the body. Our objective was to test for differences in FA in two rodent species (Apodemus flavicollis and Clethrionomys glareolus) that live in habitats suirounding the failed Chornobyl reactor. Rodents were collected from four different locations (two contaminated and two reference sites), and …

Mineralization Of Clapper Rail Eggshell From A Contaminated Salt Marsh System, Alejandro Rodriguez-Navarro, Karen F. Gaines, Christopher S. Romanek, G. R. Masson

Karen F. Gaines

The effect of contamination on eggshell mineralization has been studied for clapper rails (Rallus longirostris) inhabiting a contaminated salt marsh in coastal Georgia. To assess the impact of contaminants, the thickness, microstructure (crystal orientation), mineral composition, and chemistry of shell material were analyzed from a contaminated site and a nearby reference site using optical microscopy, X-ray diffraction, inductively coupled plasma mass spectrometry, and gas chromatography with electron capture detector. Eggshells from the contaminated site were generally thinner than those from the reference site. Also, eggshells from the contaminated site were abnormally brittle and contained anomalous microstructural attributes. The combination of …

Scarification Technique Affects Germination Of Stylisma Pickeringii (Patterson Bindweed ), An Illinois Endangered Plant, Henry R. Owen, Brent L. Todd, Janice M. Coons

Henry R. Owen

The seed coat of Stylistna pickeringii (Torr.) Gray var. pattersoni (Patterson bindweed), an endangered species of Illinois sand prairies, inhibits water uptake and seed germination. The purpose of this research was to find an effective and efficient way to scarify seeds of S. pickeringii to aid reintroduction into its natural habitat. Seeds were collected from sandy areas close to the Illinois River near Snicarte (Mason Co.), Illinois during the summers of 1998 and 1999. Experiments were conducted to determine the best scarification techniques (basal cut, sandpaper shakes, sulfuric acid, sand shakes and sonication). Initially, each technique was evaluated by scarifYing …

Cloning Of Plants, Henry R. Owen

Henry R. Owen

No abstract provided.

Discovery Of The Toxic Dinoflagellate Pfiesteria In Northern European Waters, Torstein Tengs

Dr. Torstein Tengs

Several dinoflagellate strains of the genus Pfiesteria were isolated by culturing techniques from sediment samples taken in the Oslofjord region of Norway. Pfiesteria piscicida, well known as a fish killer from the Atlantic coast of America, was identified by genetic methods and light microscopy. The related species Pfiesteria shumwayae was attracted from the sediment by the presence of fish, and has proved toxic. This present survey demonstrates the wide distribution of these potentially harmful species, but so far they have not been connected with fish kills in Europe.

Foraging Ecology And Depredation Management Of Great Blue Herons At Mississippi Catfish Farms, James F. Glahn, Brian S. Dorr, John B. Harrell, Lester Khoo

Brian S Dorr

No abstract provided.

Cellulose Synthase-Like (Csl) Genes Of Rice, Samuel P. Hazen, J. S. Scott-Craig, J. D. Walton

Samuel P Hazen

No abstract provided.

Mutant Alleles Of Arabidopsis Radially Swollen 4 And Rsw7 Reduce Growth Anisotropy Without Altering The Transverse Orientation Of Cortical Microtubules Or Cellulose Microfibrils, Tobias Baskin, A.M.D. Wiedemeier, J.E. Judy-March, C.H. Hocart, G.O. Wasteneys, R.E. Williamson

Tobias Baskin

The anisotropic growth of plant cells depends on cell walls having anisotropic mechanical properties, which are hypothesized to arise from aligned cellulose microfibrils. To test this hypothesis and to identify genes involved in controlling plant shape, we isolated mutants in Arabidopsis thaliana in which the degree of anisotropic expansion of the root is reduced. We report here the characterization of mutants at two new loci, RADIALLY SWOLLEN 4 (RSW4) and RSW7. The radial swelling phenotype is temperature sensitive, being moderate (rsw7) or negligible (rsw4) at the permissive temperature, 19°C, and pronounced at the restrictive temperature, 30°C. After transfer to 30°C, …

Newcomers "Invade" The Field Of Invasion Ecology: Question The Field's Future, Mark Davis, K Thompson

Mark Davis

No abstract provided.

A Cladistic Analysis Of The Cyphophthalmid Genera (Opiliones, Cyphophthalmi), Sarah Boyer, G. Giribet

Sarah Boyer

No abstract provided.

Variability Of Placental Expression Of Cyclin E Low Molecular Weight Variants, A Bukovsky, Maria Cekanova Ms, Rndr, Phd, Mr Caudle, J Wimalasena, Js Foster, Ja Keenan, Rf Elder

Maria Cekanova MS, RNDr, PhD

No abstract provided.

Squeaking With A Sliding Joint: Mechanics And Motor Control Of Sound Production In Palinurid Lobsters, Sheila Patek

Sheila Patek

The origin of arthropod sound-producing morphology typically involves modification of two translating body surfaces, such as the legs and thorax. In an unusual structural rearrangement, I show that one lineage of palinurid lobsters lost an antennal joint articulation, which transformed this joint from moving with one degree of freedom into a sliding joint with multiple degrees of freedom. With this sliding joint, `stick-and-slip' sounds are produced by rubbing the base of each antenna against the antennular plate. To understand the musculo-skeletal changes that occurred during the origin and evolutionary variation of this sound-producing mechanism, I examined joint morphology and antennal …