New research from the Massachusetts Institute of Technology reveals that some unlikely subjects–bacteria–can have social structures similar to plants and animals.
The research shows that a few individuals in groups of closely related bacteria have the ability to produce chemical compounds that kill or slow the growth of other populations of bacteria in the environment, but not harm their own.
Published in the September 7 issue of the journal Science, the finding suggests that bacteria in the environment can play different social roles and that competition occurs not only among individual bacteria, but also among coexisting ecological populations.
The National Science Foundation, an independent federal agency that supports fundamental research and education across all fields of science and engineering, funded the research.
“Bacteria typically have been considered purely selfish organisms and bacterial populations as groups of clones,” said Otto Cordero, a theoretical biologist and lead researcher on the paper. “This result contrasts with what we know about animal and plant populations, in which individuals can divide labors, perform different complementary roles and act synergistically.”
Cordero and colleagues from MIT, along with researchers from the French Research Institute for Exploitation of the Sea and Woods Hole Oceanographic Institution in Massachusetts, studied whether population-level organization exists for bacteria in the wild.
They reasoned social structure can reduce conflict within populations of plants and animals and determine aggression towards competing biological populations. “Think of a population of lions in the Serengeti or a population of fish in a lake,” said Cordero. But could the same be true for populations of bacteria?
“It is difficult to know what the environmental interactions really are, because microbes are too small for us to observe them in action,” said Martin Polz, an organismic and evolutionary biologist at MIT and principal investigator for the Polz Microbial Ecology and Evolution Lab. “But our research provides strong evidence that antibiotics play a role in fending off competitors.”
The researchers found evidence by looking at direct, aggressive competition between ecological populations of bacteria. They reconstructed a large network of bacterial fights–or antibiotic-mediated interactions–between bacteria from the ocean.
The scientists analyzed interactions called interference competitions, wherein bacteria produce antibiotics as a means of chemical warfare, to gain a competitive edge by directly hindering the survival of potential competitors.
This typically occurs when bacteria compete for the same portion of habitat. …
I happen to think that bacteria are aliens from space.