Year 2000 Awards
Minority Postdoctoral Research Fellowships
||Research Area/Training Plan
||NSF Award #|
|Title of Research and Training Plan|
||University of Oregon
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.
||University of California- Berkeley
|"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.
||Vanderbilt University Medical
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.
|"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.
|| Eukaryotic Genectics
"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.
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.
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.
||Michigan State University
|"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.
||SUNY, Brooklyn Health Sciences
|"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.
||University of Pennsylvania
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
||Instituto Cajal, Madrid, Spain
||National Center for Biotechnology,