Fall 2005 Asa Gray Seminars
Sept. 19th, 2005
Dr. Samuel J. McNaughton, Professor Emeritus
“Science and Conservation in the Serengeti Ecosystem,
East Africa .”
Professor McNaughton has been studying one of Earth’s great ecosystems for over 30 years. He will present results of those studies and their application to conservation policy.
Sept. 26th, 2005
Dr. Peter K. Ducey,
Department of Biological Sciences, SUNY at Cortland
"Invasive Worms Clashing in North American Soils: Everyone's Problem."
"Invasive Worms Clashing in North American Soils: Everyone's Problem."
"Invasive Worms Clashing in North American Soils: Everyone's Problem."
"Invasive Worms Clashing in North American Soils: Everyone's Problem."
The familiar earthworms of the family Lumbricidae have a major influence on physical and biological features of soils in agricultural, horticultural, and natural habitats. The status of these earthworms is currently under threat in parts of North America. Within the last 100 years, exotic, terrestrial flatworms (broadhead planarians) that eat earthworms have been spread across much of the continent. The natural history, evolution, and ecological interactions of these interesting predators will determine the extent of their impact on the earthworms. Scientific study of the flatworms is finally beginning to reveal their biology. An additional recent threat to the lumbricid earthworms is coming from a distinctly different group of worms, the invasive megascolecid earthworms from Asia. Some megascolecids can greatly alter soil structure and compete with the lumbricids for space and food. One ecological battleground for the three groups of worms is here in central New York. The desired outcomes, from a human perspective, of these ecological and evolutionary interactions remain open to considerable debate.
Oct. 17th, 2005
Dr. Manuel Morales
Dept. of Biology, Williams College
“Population Dynamics of Mutualism: Ants, Treehoppers, and Goldenrod.”
Mutualism is an interaction between species where both species benefit. I study the ecology and evolution of mutualism using the interaction between ants and treehoppers as a model system. Treehoppers are insects that feed on plant sap and excrete a sugary waste product called "honeydew." Ants collect this honeydew as a food source, and in exchange benefit treehoppers by protection from predators and by enhancing feeding. My research shows that the relative attractiveness of treehoppers to ants is the primary factor controlling the dynamics of this system. I discuss this work in the context of the evolution of interspecific signaling (e.g. communication between ants and treehoppers) and the ecology of spatial pattern formation.
Nov. 14th, 2005
Dr. Josh Ness
Dept of Biology, Skidmore College
“Integrating the quality and quantity of mutualistic service to contrast ant species visiting a plant with extrafloral nectaries."
Mutualisms (reciprocally beneficial interactions between two species) are often characterized by great variation in the benefits provided by different partner species. This variation may be due to differences among
species in the quality and quantity of their interactions, as well as the costs incurred during those interactions. Many plant species produce extrafloral nectar, a carbohydrate-rich resource, to attract ant species that can act as bodyguards against a plants natural enemies. Here, I explore differences in the quality and quantity of protective service that ants can provide a plant by contrasting the four most common ant visitors to Ferocactus wislizeni, an extrafloral nectary-bearing cactus in southern Arizona. I also ask whether the indirect costs of these plant bodyguards differ. Specifically, I ask whether these aggressive ants deter other beneficial visitors to the plant, such as pollinators. Last, I explore two strategies by which plants may increase the benefits and decrease the costs of their interactions with the ants, thereby increasing the plants net benefit from participating in the mutualism.
Nov. 21st, 2005
Dan O’Bryan
Dept. of Anatomy and Neuroscience, University of Wisconsin, Madison
"Embryonic Stem Cells: Role of genetic manipulation on differentiation”
The use of Embryonic Stem Cells (ESC) offers hope to many fields, including cell-replacement therapy and developmental biology. By genetically manipulating ESCs, key events of cell specification and differentiation can be identified. In this talk, the role of genetic manipulations on specification and differentiation of oligodendrocytes from ESCs will be analyzed.
Nov. 28th, 2005
Dr. Chandra Shekhar Bakshi
Center for Immunology and Microbial Disease
Albany Medical College, Albany, New York
"Francisella tularensis: It’s Re-emergence as a Weapon of Bioterrorism"
For rogue governments and terrorists, Francisella tularensis’s allure is that of a weapon of mass disruption. High infectivity, ease of intentional aerosol dissemination and its tinted past during the cold war has made it one of the latest targets of the U.S. government's massive R&D effort to defend against a potential bioweapon attacks. It is still unknown where this bacterium lives in the wild, how exactly it is transmitted, or even how it makes people sick. Thus, there are plenty of puzzles for the researchers to tackle. The focus of our research efforts is to elucidate the cellular and molecular mechanism(s) responsible for the development of innate immunity which, play a key role in the control of F. tularensis proliferation and alleviation of inflammation-mediated tissue damage. In order to achieve this, we are assessing the clinical course and severity of pneumonic tularemia in mice deficient for various pattern recognition receptors such as Toll like receptor-2 (TLR-2) and TLR-4. Our results have shown that TLRs play a critical role in determining the nature of innate immune response in the lungs to aerosol infection by F. tularensis live vaccine strain. Another focus of our research is to genetically manipulate F. tularensis in order to develop attenuated strains that could be used as a vaccine to populations at risk from F. tularensis infection, either from natural sources or from a biological attack. The ultimate goal is to develop novel, safe and efficacious strategies for biodefense against this potential bioterrorism agent.