Biologists from the University of Amsterdam (UvA) have discovered an alternative, previously unknown strategy of bacteria to survive starvation. This study was published in the Nature Communications on 21 February 2019.
In a human body, during the process of antibiotics, the bacteria usually go into a deep sleep where they do not require many nutrients to survive. The bacterias do not die but instead remain in a sleeping mode waiting to rise again under favorable conditions.
Under stress, the bacteria form endospores. During harsh conditions, the bacteria enclose themselves into a sturdy coat and sleeps.
Details of the research
In the study, the scientists discovered that bacteria, in fact, do not sleep but slow down exceptionally.
The research involved the study and survival function of Bacillus subtilis. Bacillus subtilis is a bacteria which is found in the soil. This bacteria can survive extreme weather conditions. This bacteria is also non-pathogenic which means it does not cause disease or harm.
Scientists used a modified Bacillus subtilis which could no longer form endospores. The scientists starved the bacteria. The scientists discovered that some of the bacteria could survive for a long period of time. The bacteria survived without being able to revive to the sleeping stage.
The bacteria takes shelter in the state which is yet unknown. The bacteria are not entirely active and nor are they sleeping. The bacteria, on the contrary, slow down the process to a very low level.
In the study the scientists observed that the bacteria did not entirely stop, rather it altered the processes it usually performs when active. When active the bacteria divide every 40 minutes. But when the bacteria became slow, the same process took place once every 4 days. This process is a hundred times slower than usual.
This slow alternate, survival strategy process is named as oligotrophic growth by the scientists. Oligotrophic growth means ‘nutrient-poor growth’.
Leendert Hamoen, professor and team leader of the study says, “The big question now is: do bacteria other than Bacillus know this trick too? If so, this fundamentally changes our outlook on bacteria. Apparently, they do not always have to form spores to survive.”
Hamoen also said, “Forming endospores requires a lot of energy, and the bacteria are not always able to 'wake up' from this condition. It is much easier for them to switch to and from this oligotrophic growth state. Once conditions improve, they can easily form new colonies. Hence this state is much more favorable for them.”
It further raises the question that how are bacteria able to escape antibiotics. If there are more bacteria found which are able to choose an alternate survival state then this a matter of concern. The need for better understanding is required.