Environmental health sciences professor and Arnold School associate dean for research Dr. Alan Decho (University of South Carolina Arnold School of Public Health) and a team of researchers have been awarded a $400k grant from the National Aeronautics and Space Administration’s Astrobiology: Exobiology Program to study cooperation and adaptability in microbial mats from extreme environments using quorum sensing. The project’s main purpose is to examine the limits of how bacteria life can survive and communicate with each other under extreme conditions both on Earth and perhaps elsewhere.
“For billions of years, bacteria and archaea have formed organized communities in microbial mats, which grow at interfaces between different types of environments,” says Dr. Decho. “Such cooperation among microbes has played determinative roles in the persistence of life and provides insight into how life on Earth and elsewhere may respond to and evolve under extreme conditions.”
The cells in a microbial mat work together using cell-to-cell signals known as quorum sensing. Genetic evidence suggests that quorum sensing developed more than a billion years ago during the early evolution of life when conditions were extremely harsh; however, little is known about how quorum sensing signaling operates in today’s extreme environments.
Using a Mars simulator chamber (in Scotland), hypersaline conditions (in the Bahamas) and lava tube environments (in Hawaii), the researchers will assess the ability of quorum sensing signaling to contribute to the survival of the microbial mats under extreme conditions; ones that mimic the habitats present on early Earth and early Mars. “These are incredibility harsh environments, where very little life other than bacteria can exist,” says Dr. Decho.
It is in these harsh environments where desiccation, or drying up, occurs—a process that few organisms can survive. Yet certain microbes, when enclosed in protective, slimy biofilms are able to dry up, and then regain activity when water returns. This “glass state” occurs everywhere on Earth, from desert crusts and lakes and streams to surgery rooms and restrooms to roofing tiles on houses.
The results from this study will have implications for both the potential for life elsewhere, including other planets and on rocks traveling through space, as well as understanding how microbial life survives on Earth. Findings will also help inform infectious disease prevention and treatment efforts as microbial mats are places where pathogens (i.e., disease-causing bacteria) can survive.