Hawaiian lava cave microbial mats appear to have the highest levels and diversity of genes related to quorum sensing so far. (Stuart Donachie, University of Hawai`i at Mānoa)
Did you know that many bacteria — some of the oldest lifeforms on Earth — can talk? Really.
And not only between the same kind of single-cell bacteria, but back and forth with members of other species, too.
Okay, they don’t talk in words or with sounds at all. But they definitely communicate in a meaningful and essential way, especially in the microbial mats and biofilms (microbes attached to surfaces surrounded by mucus) that constitute their microbial “cities.”
Their “words” are conveyed via chemical signaling molecules — a chemical language — going from one organism to another, and are a means to control when genes in the bacterial DNA are turned “on” or “off.” The messages can then be translated into behaviors to protect or enhance the larger (as in often much, much larger) group.
Called “quorum sensing,” this microbial communication was first identified several decades ago. While the field remains more characterized by questions than definitive answers, is it clearly growing and has attracted attention in medicine, in microbiology and in more abstract computational and robotics work.
Most recently, it has been put forward as chemically-induced behavior that can help scientists understand how bacteria living in extreme environments on Earth — and potential on Mars — survive and even prosper. And the key finding is that bacteria are most successful when they form communities of microbial mats and biofilms, often with different species of bacteria specializing in particular survival capabilities.
Speaking at the recent Astrobiology Science Conference in Seattle, Rebecca Prescott, a National Science Foundation Postdoctoral Research Fellow in Biology said this community activity may make populations of bacteria much more hardy than otherwise might be predicted.
Quorum sensing requires a community. Isolated Bacteria (and Archaea) have nobody to communicate with and so genes that are activated by quorum sensing are not turned “on.”
“To help us understand where microbial life may occur on Mars or other planets, past or present, we must understand how microbial communities evolve and function in extreme environments as a group, rather than single species,” said Prescott,
“Quorum sensing gives us a peek into the interactive world of bacteria and how cooperation may be key to survival in harsh environments,” she said.
Rebecca Prescott is a National Science Foundation Postdoctoral Fellow in Biology (1711856) and is working with principal investigator Alan Decho of the University of South Carolina on a NASA Exobiology Program grant.
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