When things don’t go well, some bacteria they have a brilliant plan: if they notice, for example, that they are going to go hungry or find themselves in environments that are hostile to them, they keep a copy of their ADN in form of spore. In this new state they can resist radiation, heat, and even being literally crushed and crushed. They become a kind of ‘dust’ in which they can remain even for thousands of years. But this is not a definitive way: if conditions improve, these spores ‘resurrect’ and become bacteria again.
For example, him anthrax that some terrorist groups introduced in envelopes and packages had this capacity: when the victim inhaled the anthrax spores, they entered his body. Once inside the body, in a matter of minutes and more favorable humidity and heat conditions, they would be activated again, turning back into bacteria; thus they multiplied, spread and produced toxins that caused a very serious disease. Another example is the spores locked in the ice of the permafrostwhich have remained frozen for thousands of years, now activating with the thaw, as many studies have reported.
Although scientists have known about this process for a long time, they did not know if the spores could ‘scan’ their environment while they were ‘sleeping’, without waking up if not necessary. Now, a study published in ‘Science’ seems to have found the answer: they are capable of doing it. And, in addition, they use a system similar to the one used by our neurons.
They are not inert, as was thought
The research team, made up of biologists from the University of California, San Diego (USA), discovered that spores have an extraordinary ability to assess the environment that surrounds them even when they are in a physiologically dead state: they use stored electrochemical energy , which acts as a kind of condenser, and they use it at specific moments to determine if the conditions are adequate to return to normal life.
“This work changes the way we think about spores, which were considered inert beings,” he explains. Gurol Suel, professor in the Department of Molecular Biology at the University of California. “We show that cells in a deeply dormant state have the ability to process information: spores can release their previously stored electrochemical potential energy to assess their environment without needing to initiate metabolic activity.”
How they ‘feel’ despite being ‘dead’
Süel and his colleagues used spores from Bacillus subtilis, a common bacterium that can be found in various habitats, and they subjected it to short environmental stimuli that they knew were not capable of bringing them back to life. By monitoring the spores, they realized that they had a kind of ‘internal count’ in which each stimulus was added; if they all reached a certain threshold, the spores were activated and resumed biological activity.
In developing a mathematical model to help explain the process, the researchers realized that spores use a mechanism to assess the surrounding environment known as ‘integration and shooting‘, based on potassium ion fluxes: when the spores receive a favorable stimulus, even a short one, they release part of the stored potassium. When they add up a series of positive signals, each marked with the potassium burst, then they come back to life. Something like filling a kind of ‘vital bar’ with each of these signals; in the case of reaching a limit, the spore is activated and transforms into a bacterium.
“The way the spores process information is similar to how neurons operate in our brain,” Süel says. In both bacteria and neurons, small, brief inputs are summed to determine whether a threshold is reached. Upon reaching it, the spores begin their return to life, while the neurons fire an action potential to communicate with other neurons.” Interestingly, spores can perform this integration of signals without requiring metabolic energy – that is, they can carry out this action without the need for a ‘living body’ – while neurons are among the most energy-dependent cells in our body. .
Implications for possible life beyond Earth
Bacteria, in the state of spores, can survive even in space, so they are firm candidates to become the first extraterrestrial life that we find beyond Earth -if we find it-.
“This work suggests alternative ways to deal with the potential threat posed by pathogenic spores, but also implications for what to expect from extraterrestrial life,” Süel concludes. “If scientists find life on Mars or Venus, it is likely to be in a dormant state. And now we know that a life form that appears to be completely inert may still be able to think of its next steps.”