Carnegie Institution of Washington

Carnegie Institution

News Release

September 24, 2003

Contact Devaki Bhaya 650-325-1521 x 283, devaki@andrew2.stanford.edu; Arthur Grossman 650 325 1521 x212, arthur@andrew2.stanford.edu; or Tina McDowell in the Carnegie Publications Office 202 939 1120

The concept of a bacterial species: Are things heating up?

Stanford, California. A new study may revolutionize the concept of species—at least in the world of bacteria. On September 24, the National Science Foundation announced their award of a $5-million, 5-year grant to a group* of scientists, including investigators at the Carnegie Institution’s Department of Plant Biology in Stanford, California, to study some of the tiny photosynthetic creatures that live in near-boiling pools in Yellowstone National Park. The organisms, known as cyanobacteria, are among the microbes that inhabit the thick, colorful mats in the thermal pools.

Carnegie’s Dr. Devaki Bhaya, one of the researchers on the team, explains: “It’s easy to think that microbes that look the same under the microscope are all the same genetically. Yet we know that even within these simple microbial mats there are tremendous differences generated over thousands of years of evolution. This raises several questions: Have the same species undergone genetic radiation to populate relatively different microenvironments? Have different, but morphologically similar species become specialized for specific niches within the mats? Is evolution of the mat structure linked to the flow of genetic information between organisms?”

By using a host of sophisticated molecular and genomic tools, the team should be able to identify genetic differences among bacteria that comprise the microbial mats, determine the extent to which they promiscuously exchange genetic information, and shape this information into ideas about how the community became structured over time. Perhaps the results will clarify some of the controversies surrounding the concept of what constitutes a bacterial species, or determine if the term species should even be applied to bacteria.

Dr. Arthur Grossman, also at Carnegie, additionally wants to know how a photosynthetic organism can survive in temperatures that scald the human hand. “Developing an understanding of the different cyanobacterial 'ecotypes' that populate the hot springs will provide us with clues of what constitutes fitness and what limits that fitness within the confines of a highly structured environment,” he commented.

The scientists believe that local environmental differences are the major driving force behind the different genetic groups of the cyanobacterium, Synechococcus, which is dominant in the hot springs. The interdisciplinary team will probe the problem from a variety of perspectives including genomics, microbial physiology, environmental science, bioinformatics, and mathematical modeling to untangle the complex interactions that occur within this environment. Carnegie researchers will use DNA microarrays and other technology to get a glimpse of genes that are turned on in these cyanobacteria as they acclimate to changing mat environments over daily and seasonal cycles. The possible discovery of genetically and physiologically separable ecotypes will broadly impact thinking in microbial evolution and bacterial ecology.

Images available at www.carnegieinstitution.org/cyanobacteria/

*The National Science Foundation, Frontiers in Integrative Biological Research (FIBR) study—“Do Species Matter in Microbial Communities?” (Award No. EF-0328698)is led by principal investigator Dr. David Ward at Montana State University. The study’s interdisciplinary team is made up of scientists from the following institutions: Montana State University, Wesleyan University, The Institute for Genomic Research, The University of Copenhagen, Stanford University/Carnegie Institution of Washington, and Lockheed-Martin.

The Carnegie Institution of Washington (www.CarnegieInstitution.org) has been a pioneering force in basic scientific research since 1902. It is a private, nonprofit organization with six research departments in the U.S.: Plant Biology and Global Ecology in Stanford, CA.; The Observatories in Pasadena, CA, and Chile; Embryology, in Baltimore, MD.; and the Department of Terrestrial Magnetism and the Geophysical Laboratory in Washington, D.C.