The following projects are available to students in the summer of 2008:

• Extreme Prokaryotes in Extreme Habitats (Dr. Anthony Lobo)
• Mammalian Ecology (Dr. Ellen Dawley or Dr. Robert Dawley)
   

1. Extreme Prokaryotes in Extreme Habitats (Dr. Anthony Lobo).
   • Extremes in the physical parameters of an environment- most notably temperature and salt concentration- limit the diversity of organisms capable of inhabiting them.
   • Microorganisms of the domain Archaea are often the only organisms that exist in these extreme environments.
   • These prokaryotes are uniquely adapted to cope with environmental extremes and studying them and the means by which they do has led us to a better understanding of biodiversity and the limits of living systems.
   • Dr. Lobo’s lab is currently studying a number of species of extremely halophilic archaea in our laboratory.
     One species they study, Halorubrum coriense, is host to the halophilic phage HF2.
   • They observed recently that H. coriense was more susceptible to infection by HF2 during the stationary phase of growth than during exponential growth and that when exponential-phase cells were exposed to culture supernatants of stationary-phase cultures-- the exponential-phase cells became more susceptible as well.
   • This intriguing findings suggests the possibility that H. coriense changes its physiology in stationary phase by some quorum sensing mechanism—some chemical communication between the bacteria.
   • Dr. Lobo’s lab is currently further investigating this possibility.
   • To this end, Dr. Lobo is carrying out three types of projects, all of which will be conducted by Ursinus undergraduates and those invited through the REU site.
   • The first is the identification and characterization of the factor involved in signaling H. coriense stationary-phase cells.
   • At the moment, they know only that the crude culture supernatants confer stationary-phase behavior, so we are proceeding to fractionate the supernatant to identify the factor.
   • Students with coursework in organic chemistry, biochemistry and analytical chemistry will bring expertise to this project; analytical chemical methods through the Ursinus College Chemistry department are at our disposal.
   • The second project is a broader survey of cultures of extremely halophilic archaea for the presence of molecules associated with quorum sensing.
   • Students can explore this group using a variety of biosensor organisms which have been engineered to respond to a range of quorum sensing molecules.
   • The third is an open-ended project aimed at identifying other behaviors in extremely halophilic archaea that may be controlled through quorum sensing.
   • For example, Dr. Lobo and his students have noticed that many of these species form visible biofilms in their culture containers late in growth.
   • They wish to investigate the possibility that biofilm formation by extremely halophilic archaea is controlled by quorum sensing, as it is in some species of bacteria.
   • Students will be encouraged to identify, through observation of cultures and study of the literature, other density-related changes in cell appearance, behavior, or physiology.

   Dr. Anthony Lobo earned his Ph.D. at Cornell University and was a postdoctoral fellow at the University of Wisconsin. He taught at the State University of New York and at Swarthmore College before joining the Ursinus faculty. He is a winner of the Lindbach Teaching Award. Dr. Lobo teaches microbiology, cell biology, immunity, and molecular biology courses.

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2. Mammalian Ecology (Dr. Ellen Dawley or Dr. Robert Dawley - please specify on your application)
   • Small mammal abundances are frequently used to estimate biodiversity, especially when considering anthropogenic habitat changes.
   • Southern Pennsylvania has been greatly affected by human population expansion, yet pockets of forested areas remain, frequently as a result of open spaces initiatives.
   • A broad area of inquiry pursued by students interested in field work in Dr. Dawley’s lab is small mammal species richness and behavior.
   • We have recently been studying small mammal biology on Montgomery County park lands.
   • Possible projects that could be pursued include a study of diversity in one locality of Montgomery County park lands compared to other localities that are more restricted in size and adjacent to human housing and traffic (e.g., the Perkiomen Trail, a reclaimed railroad bed that has been converted into a pedestrian/bike trail).
   • This project would provide an assessment of the efficacy of pockets of suitable habitat within larger suburban/rural tracts in maintaining species richness.
   • Another project might include marking individual small mammals or attaching transmitters and tracking movements and behaviors.
   • As a final example, students could examine olfactory behavior of small mammals and corresponding morphological adaptations.

   Dr. Ellen Dawley earned her Ph.D. at the University of Connecticut in Ecology and Evolution. She taught at Cornell University where she also did postdoctoral research before coming to Ursinus College. Dr. Dawley is chairman of the Pre-Medical committee, winner of the Lindbach Teaching Award, and former chair of the Biology Department. She teaches mammalogy, and courses on organismic and evolutionary biology.
   
   Dr. Robert Dawley earned his Ph.D. at the University of Connecticut in Ecology and Evolution. He is a former chair of Biology Department and winner of the Lindback Teaching Award. He was instrumental in the development of the Ursinus College Environmental Studies Program, and has developed courses in tropical ecology in Costa Rica and Mexico. He taught at Cornell University and Bowdoin College before coming to Ursinus College. He was coeditor of a landmark book entitled: The Ecology and Evolution of Unisexual Vertebrates. New York State Museum of Natural History Press, N.Y. in 1989.

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