Organizational Unit:
School of Biological Sciences

Permanent Link
https://hdl.handle.net/1853/70750
Research Organization Registry ID
Description
Previous Names
Parent Organization
Parent Organization
Organizational Unit
Includes Organization(s)
ArchiveSpace Name Record
https://finding-aids.library.gatech.edu/agents/corporate_entities/1131

Filters

2000 - 2009 77 2010 - 2011 1
1
77
77
Reset filters

Settings
End date: 2003 × Start date: 2000 × Item Type: Publication × search.filters.applied.f.isOrgUnitOfPublicationTitle: College of Sciences ×

Publication Search Results

Now showing 1 - 10 of 77
Thumbnail Image
Item

American scientists survey-phase II

2011-03-15 , Walsh, John P. , Huang, Hsin-I , No, Yeonji , Wartell, Roger M. , Bayer, Charlene W. , Tornabene, Thomas G.

View
Thumbnail Image
Item

Palatability and defense of some tropical infaunal worms: alkylpyrrole sulfamates as deterrents to fish feeding

2003-11-28 , Kicklighter, Cynthia Ellen , Kubanek, Julia , Barsby, Todd , Hay, Mark E.

Numerous studies have investigated chemical defenses among sessile species growing on hard substrates, but few have addressed this for mobile species in soft-sediment communities. We investigated the palatability and potential chemical defenses of 11 worm species from soft-sediment systems in southern Florida, USA. Three species were unpalatable to the bluehead wrasse Thalassoma bifasciatum. The polychaete Cirriformia tentaculata and the hemichordate Ptychodera bahamensis were uniformly unpalatable. For the polychaete Eupolymnia crassicornis, the exposed tentacles were unpalatable, but the body, which remains protected in a deeply buried tube, was palatable. These unpalatable worms were chemically defended; extracts of C. tentaculata, P. bahamensis, and the tentacles of E. crassicornis deterred fish feeding. For C. tentaculata, bioassay-guided fractionation demonstrated that a mixture of 3 closely related alkylpyrrole sulfamates deterred fish at naturally occurring concentrations (2-n-hexylpyrrole sulfamate [1.6% of worm dry mass], 2-n-heptylpyrrole sulfamate [3.1% dry mass], and 2-n-octylpyrrole sulfamate [0.8% dry mass]). This appears to be the first documentation of characterized natural products defending a marine worm from consumers. For P. bahamensis and the tentacles of E. crassicornis, deterrent effects of crude extracts decomposed before specific compounds could be identified

View
Thumbnail Image
Item

Impact of fiddler crabs and plant roots on sediment biogeochemistry in a Georgia salt marsh

2003-09-12 , Gribsholt, Britta , Kostka, Joel E. , Kristensen, Erik

The influence of macrofauna and macrophytes on sediment biogeochemistry was quantified in a Spartina alterniflora (Loisel) saltmarsh, with emphasis on sulfur and iron cycling. Vertical profiles of sediment geochemistry and rates of microbial metabolism at 3 sites with different abundances of fiddler crab Uca pugnax burrows, vegetation coverage and hydrology were supplemented with high-resolution radial profiles around burrow walls and S. alterniflora roots. Carbon oxidation was measured as sulfate reduction using the 35S technique, as total anaerobic CO2 production, and as Fe(III) reduction by monitoring Fe(II) evolution. Depth-integrated (0 to 10 cm) sulfate reduction was 25% lower, while total Fe and Fe(III) concentrations were 1.5 and 6 times higher, respectively, in bioturbated than in nonbioturbated sediment. Low sulfate-reduction rates adjacent to burrow walls (3% of those in bulk sediment) were counteracted by very high Fe(III) reduction rates. Thus, Fe(III) reduction accounted for 54 to 86% of the total carbon oxidation within 4 cm distance of burrows, decreasing in importance with distance from the burrow wall. Overall, S. alterniflora roots showed a greater impact on sediment biogeochemistry than crab burrows. Sulfate reduction was almost absent in the rhizosphere, whereas Fe(III) reduction rates (6.2 µmol Fe cm-3 d-1) were among the highest reported for marine sediments, accounting for >99% of carbon oxidation. Our results confirm the universal relationship between the contribution of Fe(III) respiration to total carbon oxidation and solid Fe(III) concentrations that has been suggested based on studies of subtidal marine sediments. The importance of Fe(III) respiration was strongly dependent on Fe(III) concentrations below levels of 30 µmol cm-3, whereas above this level almost all anaerobic respiration was mediated by Fe(III) reduction in saltmarsh sediments.

View
Thumbnail Image
Item

Scaling and the swimming kinematics of the pteropod, limacina helicina

2003-08 , Chan, Yin

View
Thumbnail Image
Item

Thermodynamic studies of tandem mismatches and other structural elements in Hairpin and duplex nucleic acids

2003-12-01 , Bourdelat-Parks, Brooke Nicole

View
Thumbnail Image
Item

Unfolding of globular proteins: monte carlo dynamics of a realistic reduced model

2003-11 , Kolinski, Andrzej , Klein, Piotr , Romiszowski, Piotr , Skolnick, Jeffrey

Reduced lattice models of proteins and Monte Carlo dynamics were used to simulate the initial stages of the unfolding of several proteins of various structural types, and the results were compared to experiment. The models semiquantitatively reproduce the approximate order of events of unfolding as well as subtle mutation effects and effects resulting from differences in sequences of similar folds. The short-time mobility of particular residues, observed in simulations, correlates with the crystallographic temperature factor. The main factor controlling unfolding is the native state topology, with sequence playing a less important role. The correlation with various experiments, especially for sequence-specific effects, strongly suggests that properly designed reduced models of proteins can be used for qualitative studies (or prediction) of protein unfolding pathways

View
Thumbnail Image
Item

Retrotransposons and their recognition of pol II promoters: A comprehensive survey of the transposable elements derived from the complete genome sequence of Schizosaccharomyces pombe

2003-09 , Bowen, Nathan J. , Jordan, I. King , Epstein, Jonathan A. , Wood, Valerie , Levin, Henry L.

The complete DNA sequence of the genome of Schizosaccharomyces pombe provides the opportunity to investigate the entire complement of transposable elements (TEs), their association with specific sequences, their chromosomal distribution, and their evolution. Using homology-based sequence identification, we found that the sequenced strain of S. pombe contained only one family of full-length transposons. This family, Tf2, consisted of 13 full-length copies of a long terminal repeat (LTR) retrotransposon. We found that LTR-LTR recombination of previously existing transposons had resulted in extensive populations of solo LTRs. These included 35 solo LTRs of Tf2, as well as 139 solo LTRs from other Tf families. Phylogenetic analysis of solo Tf LTRs reveals that Tf1 and Tf2 were the most recently active elements within the genome. The solo LTRs also served as footprints for previous insertion events by the Tf retrotransposons. Analysis of 186 genomic insertion events revealed a close association with RNA polymerase II promoters. These insertions clustered in the promoter-proximal regions of genes, upstream of protein coding regions by 100 to 400 nucleotides. The association of Tf insertions with pol II promoters was very similar to the preference previously observed for Tf1 integration. We found that the recently active Tf elements were absent from centromeres and pericentromeric regions of the genome containing tandem tRNA gene clusters. In addition, our analysis revealed that chromosome III has twice the density of insertion events compared to the other two chromosomes. Finally we describe a novel repetitive sequence, wtf, which was also preferentially located on chromosome III, and was often located near solo LTRs of Tf elements.

View
Thumbnail Image
Item

Automation of comparative genomic promoter analysis of DNA microarray datasets

2003-12-01 , Karanam, Suresh Kumar

View
Thumbnail Image
Item

Role of olfactory appendages in chemically mediated orientation of blue crabs

2003-10-17 , Keller, Troy A. , Powell, Ian , Weissburg, Marc J.

Benthic crustaceans such as the blue crab Callinectes sapidus use various sensory appendages to navigate chemical plumes. We characterized the role of different sensory structures in blue crabs during olfactory search by deafferenting (i.e. removing or rendering inactive) particular sensor populations and by quantifying odor-plume structure and flow dynamics. Our results indicate that blue crabs use both cephalic and thoracic appendages for olfactory-mediated orientation. Cephalic chemosensor deafferentation decreased search success, reduced walking speed and increased the duration of stationary periods. All these deficiencies are manifestations of the inability of crabs to sustain upstream progress. Crabs subjected to deafferentation of thoracic sensilla failed to correctly track the narrowing plume and showed an increased frequency of large course-corrections. Whereas cephalic sensors clearly function in motivating upstream movement during the search process, thoracic receptors aid in source localization. The differing functional roles of these 2 sets of appendages may be associated with different signal characteristics impinging on their chemosensor populations. Intermittent but intense signals received by the cephalic appendages may enable the crabs to identify attractive odors and sustain searching. Chemical signals impinging on legs are more homogeneous and may allow the crabs to acquire better information on the spatial patterns of chemical signal structure that are important for navigation. The simultaneous use of chemical signals at differing heights in the plume suggest that the 3D structure of these plumes is important for foraging success, and that different populations of neural receptors may be tuned to operate optimally in particular signal environments.

View
Thumbnail Image
Item

Improving gene annotation of complete viral genomes

2003-08 , Mills, Ryan E.

View