Fiscal Year 2001 Awards
Minority Postdoctoral Research Fellowships
Emilio M. Bruna Instituto Nacional-Pesquisas da Amazonia Ecology 0109226
"Are ant-plant mutualisms disrupted in rainforest fragments?"
The subtitle is "Influence of fragment size and edge proximity on ant colon establishment,
growth, and defense against herbivores." This research investigates how rain forest
fragmentation impacts plants and the ants that defend them from herbivores. In addition to
determining if the community of ant-plant mutualists is reduced in fragments, a focal ant-plant
system is being used to experimentally investigate three potential mechanisms by which ant-
plant mutualisms can be altered in forest fragments. The fieldwork is being carried out in
Leslie A. Cornick Univ Alaska-Fairbanks Integrated Animal Biology 0109230
"Understanding the physiological and biochemical effects of increased hydrostatic pressure
in seals and sea lions: how can they dive so deep?"
The physiological limits to diving in marine mammals focus on two restrictions: how long
can the animal breath-hold and how deep can it dive? Within these limits, animals hunt by
choosing a foraging strategy that balances the obligate costs with the potential energetic gains
of foraging. In order to incorporate a more complete picture of the physiological and
biochemical limitations to diving into optimal foraging models for diving mammals, this
research is examining red blood cell membrane changes and non-glycolytic pathway
responses to increased hydrostatic pressure.
Gerald B. Downes University of Pennsylvania Developmental Neurobiology 0109217
"Genetic analysis of spinal cord circuit formation in the zebrafish embryo."
Large-scale genetic screens have revealed zebrafish motility mutants that abnormally
contract muscles on the left and right sides simultaneously, suggesting a disruption of spinal
cord circuits that coordinate motor output. The goal of this research is to examine these
mutants to elucidate the precise cellular and molecular events required for spinal cord circuit
Ernesto J. Fuentes University of North Carolina Cell Biology 0109211
"Functional aspects of Dbl homology proteins as molecular switches in cell signaling."
Communication within a cell is vital for the maintenance of normal cellular function. Studies
being conducted are aimed at deciphering the basic molecular aspects of function and
regulation of a Dbl homology protein, a vital component in cellular signaling. These studies
are aimed at determining the general mechanism of function using structural, biochemical
and cell-based approaches.
Kevin S. Jones Instituto Cajal, Madrid Neuronal/Glial Mechanisms 0109195
"Investigating the Merging of Ionotropic and Metabotropic Signals at the Ionotropic Kainate
Neurotransmission at chemical synapses is carried out by two distinct classes of receptors-
ionotropic and metabotropic. Ionotropic receptors are ligand-gated ion channels that respond
to neurotransmitters by allowing ion flux across cell membranes. Metabotropic receptors,
however, mediate neurotransmission less directly by activating second messenger molecules
which subsequently modulate cellular communication. Contemporary models of
neurotransmission maintain that the signals evoked by ionotropic and metabotropic receptors
are autonomous and exclusive. Recent data, however, suggests that kainate receptors,
members of the ionotropic glutamate receptor family, may be capable of initiating both
ionotropic and metabotropic signals. This research is elucidating the merging of these
distinct signaling pathways by (1) reconstituting the putative pathway in a heterologous
expression system; and (2) identifying proteins that directly interact with the ionotropic
kainate receptors as potential mediators of metabotropic coupling. These aims are being
achieved by utilizing Xenopus oocyte expression and yeast two-hybrid screening,
Paul M. Magwene Yale University Biological Databases/Informatics 0109224
"Statistical tools for analyzing gene expression data."
The goal of this research is to develop statistical tools for analyzing gene expression data
derived from DNA microarray experiments and to generate an analytical framework for
relating distributions of gene expression profiles to variation in phenotypic traits. Particular
emphasis is being paid to developing methodologies that incorporate a priori biological
knowledge and that facilitate the development and testing of biological hypotheses.
James P. Martinez Oregon State University Prokaryotic Genetics 0109202
"Analysis of a host-selective toxin gene, ToxB, from the fungus that causes tan spot disease
Toxin production is one strategy that fungi use to infect plants. The fungus, Pyrenophora
tritici-repentis, is a pathogen of wheat due to the production of host-selective toxins. To
better understand how this pathogen interacts with its host, this research is characterizing a
toxin gene (ToxB) and its protein product(s). A similar gene (toxb) from non-pathogenic
fungal isolates is also being cloned and evaluated in comparison to the pathogenic form.
Maria J. Martinez University of New Mexico Cell Biology 0109235
"Genetically defining the non-dividing state of the cell."
It has been debated, for cells that have stopped growing, whether they have simply paused
in their growth cycle or whether they have entered a physiologically different state, referred
to as G0. To distinguish between cycle arrested and G0 cells, this research is using
microarray analysis on growth arrested cells of the yeast, Saccharomyces cerevisiae.
Aileen A. Rubio University of California-San Diego Cell Biology 0109229
"Understanding how membrane proteins involved in sporulation reach their proper
All cells can target proteins to specific locations, but the mechanism for this process is
poorly understood in bacterial systems. During sporulation in Bacillus subtilis, many
membrane proteins are specifically localized within the cell to division sites. Through
mutant analyses and fluorescence microscopy using GFP fusions, this research is gaining a
more detailed picture of how bacteria send proteins to specific regions of the cell.
James A. Schulte National Museum of Natural History Population Biology 0109205
"Evolution of morphological diversity in iguanian lizards."
This research compares the evolution of morphological diversity among and within two
lizard families, Agamidae and Iguanidae. The goal is to identify clades that have evolved
greater morphological disparity than other clades, test for common ecomorphological
patterns within and between groups, and test for an association between increased
morphological disparity and diversification rates using a phylogenetic context.
Maria Uriarte Institute of Ecosystem Studies Population Biology 0109223
"Evolution of herbivore defense strategies in an invasive plant."
The invasive weed Hypericum perforatum, L. (St. John's wort) is being used in this study of
the evolution of defense strategies against insect herbivory. The genetic basis of resistance
and tolerance are being determined by developing a genetic map of resistance and tolerance
traits, investigating tradeoffs between traits conferring resistance versus tolerance, and
examining whether tradeoffs vary between native and introduced populations with differing
histories of biological control.