Fiscal Year 2000 Awards

Minority Postdoctoral Research Fellowships

Fellow's Name Host Institution Research Area/Training Plan NSF Award #
Title of Research and Training Plan

Robert Bellsey University of Oregon Population Biology 0078413
"Examining riverbank restricted plants to determine if there is a pattern of genetic diversity coinciding with the structure of the watershed"
Riparian plants may periodically be scoured out by seasonal floodwaters. Plant populations high in the watershed are less influenced by stochastic effects and may provide a source of migrants to recolonize regions downstream. This research compares genetic structure to spatial structure of the populations and estimates the relative importance of migration, founder effects and genetic drift. This study illustrates the potential role of population genetic structure for management efforts in terrestrial riparian corridors.

Marc Carrasco University of California- Berkeley Population Biology 0001988
"Elucidation of Paleobiogeographic Patterns of Late Oligocene/Miocene Time Period"
This project assesses the effects of large-scale tectonic and climatic perturbations from 30 to 5 million years ago in the western United States on the distributions of fossil and extant mammalian taxa. These effects are determined through the use of a GIS database of fossil taxa, Parsimony Analysis of Endemicity, and biogeographic information on extant taxa. Three hypotheses are tested: 1. Large-scale tectonic changes between thirty and five million years ago restricted gene flow and increased endemism in mammals; 2. Modern biogeographic patterns are more deeply rooted in Earth history rather than being the result of recent climatic events such as Pleistocene glaciation; 3. Mammalian species behave individualistically during times of climate change as opposed to maintaining static species' associations. This study will provide a better understanding of the role played by the physical environment on evolution as well as an increased understanding of how future climate and tectonic changes will affect biodiversity.

Ana Estevez Vanderbilt University Medical Center Biomolecular Processes 0001986
"G-protein Regulation of a Volume-Sensitive Anion Channel"
This research examines the ability of cells to sense and respond to changes in cell volume, a vital housekeeping activity that also serves important roles in growth, proliferation, and apoptosis or "programmed cell death". Cell volume homeostasis is mediated primarily by ion channels, or Volume-Sensitive Organic Osmolyte Anion Channels (VSOAC), which release chloride and other organic osmolytes in response to swelling. Initial studies have demonstrated that these VSOACs are stimulated by G-protein activiation. This research investigates 1. The role of Rho GTPase and cell swelling on VSOAC activation, and 2. The role of actin cytoskeleton, the cell's "skeleton" whose structure and function are known to be regulated by Rho GTPase.

Manuel Leal Union College Sensory Systems 0001982
"Habitat Light and the Evolution of Visual-Signal Design"

Signal diversity in animals may be explained by selection pressures for particular signals and sensory systems based on optimal transmission and detection efficiency, as described by the sensory drive hypothesis (SDH). The SDH may play an important role in genetic isolation of populations and, in turn, speciation. This research examines six allopatric (i.e. occurring in different locations) populations of the lizard Anolis cristatellus found in two distinct habitat types. Habitat light, visual-system response, and signal design are examined. This study provides a greater understanding of the role of sensory drive in the generation of signal diversity and its potential role in the formation of new species.

Reine Protacio Harvard University Eukaryotic Genectics 0001979

"Analysis of the Role of Bulk Chromatin Proteins in Regulating Meiotic Recombination in the Yeast Saccharomyces cerevisiae"

This research investigates the role of general chromatin configuration in regulating crossover recombination. In particular, the functions of bulk chromatin proteins Bdf1, Hho1, Dot1, and Chd1 in meiosis in yeast S. cerevisiae are being examined via two independent approaches: 1. Various events of meiosis are analyzed in cells whose genes encoding these proteins have been deleted, and 2. Proteins that display significant meiotic function are characterized in wild-type cells at different stages of meiosis. Also, chromosomal localization of relevant proteins are being examined.

Alberto Roca Rice University Biomolecular Processes 0001976
"Understanding Recombinational DNA Repair Initiation: A Kinetic Analysis of RecA-DNA Complex Formation"
This research seeks to provide a complete analysis of the functioning of RecA, a protein involved in recombinational DNA repair. Until now, the molecular mechanisms by which it functions have not been described. Of particular interest is whether or not ATP induces a conformational change of RecA into an active state, prior to DNA binding. Spectroscopic signal changes from fluorescent oligonucleotides (multiple DNA bases linked in series) are used to detect DNA binding (i.e. formation of the RecA-DNA complex), while complex formation is followed in real-time using stopped-flow techniques. The specific molecular steps involved are being characterized.

Javier Rodriguez University California-Berkeley Population Biology 0001975
"Genetic Variation Among Populations of Amphibians and Reptiles from the Caribbean Island of Puerto Rico"
This research is a phylogeographic study of ten species of reptiles and amphibians endemic to the Carribbean island bank of Puerto Rico. Phylogeography consists of the principles and processes that govern the geographical distribution of genealogical lineages, especially those at the intraspecific level. Comparative mitochondrial DNA phylogeographic studies of the selected reptilian and amphibian species are being conducted in order to determine whether their current genetic structure has been predominantly influenced by older geological events and climatic changes versus more recent phenomena.

Sean Veney Michigan State University Behavioral Neuroscience 0001973
"The Role of Neurocalcin and Calcium Binding in Development of the Zebra Finch Telencephalon"
This study examines the developing female Zebra Finch brain and the role of neurocalcin (a calcium binding protein) on neuronal development. Expression of neurocalcin in the female brain has been shown via amplification of RNA. Northern blot analysis, which identifies presence of RNA and thus gene expression, is being used to determine the time-course of neurocalcin expression throughout the entire period of sexual differentiation, and in-situ hybridization demonstrates its localized expression. Finally, calcium imaging is used to investigate the potential sex differences as a function of free calcium, which might be induced by increased neurocalcin in females.

Dani Smith SUNY, Brooklyn Health Sciences Center Behavioral Neuroscience 0001971
"Regulation of Synaptic Plasticity by Subpopulations of NMDA Receptors"
Long-term potentiation (LTP), long-term depression (LTD), and depotentiation are persistent and long-lasting changes in synaptic function that may underlie the cellular mechanisms for learning and memory. This research examines the function of the NMDA receptor (a post-synaptic receptor that induces neuronal firing in glutaminergic neurons) in LTP, LTD, and depotentiation. The role of specific NMDA receptor subunits (i.e. components) is assessed in the hippocampus of mice, an area of the chemicals that have binding affinities to specific subunits, as well as by use of gene-targeted knockout mice (mice whose genes encoding specific receptor subunits have been deleted and therefore do not express them). In addition, to determine if LTD and depotentiation share similar maintenance mechanisms, biochemical assays are performed to ascertain shared understanding of the molecular basis of synaptic plasticity.

Herschel Wade University of Pennsylvania Biophysics 0001969
"Protein Engineering of a Model Protein"
This study uses a synthetic diiron-oxo protein (DF) as a model for the class of metalloproteins that performs a variety of functions in living systems including dioxygen transport, conversion of ribonucleotides to deoxyribonucleotides, desaturation of fatty acids, and the solubilization and storage of iron. DF has been designed to serve as a minimal model of diiron-oxo proteins and has been shown to contain a metal center that is very similar to the diiron-oxo proteins. The model is interesting because the dinuclear metal centers in all diiron-oxo proteins contain many common structural features, but at the same time contain subtle differences that give rise to different activities. This makes the diiron-oxo system attractive for studying how protein environments can influence active site functions. This projects seeks to refine the first generation DF system into one that is amenable for engineering and designing efforts and for studying diiron-oxo protein function by (1) developing an efficient synthesis of DF which would offer a quick way to generate large numbers of DF variants and (2) by investigating the determinants for the function and structure of the center by systematically altering the atoms near the active site. Completing these goals will guide efforts towards designing pre-defined functions into the diiron-oxo centers.


Minority Graduate Student Travel Award

Kevin Jones Instituto Cajal, Madrid, Spain Neuronal Mechanisms 0004341

Ousmane Toure National Center for Biotechnology, Braunsweig, Germany Metabolic Biochemisty 0000892