Fiscal Year 2001 Awards

Minority Postdoctoral Research Fellowships

Fellow’s Name             Host Institution             Research Area             NSF Award #


Title of Research & Training Plan



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

on wheat."


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.