Hello there! It’s been a while since I’ve written about anything related to space but let’s bring that back, shall we? In part 3 of this series, I will be discussing how microbes have managed to survive in space much so easily compared to other groups of organisms. You can read my previous post on how we conduct testing on microbes over here: Testing micro-organisms in space!.
In this post, we will discuss a little more on how microbes have developed adaptive mechanisms to cope with the harsh conditions that outer space has to offer. My intention with this article is that once you read it, you understand exactly why studying microbes under conditions in space is important. Also, how studying them and their survivability can help answer any questions about genetic mutations and survivability.
What changes occur at the molecular level?
In my previous posts, I’ve discussed how microbes have been studied in space and even outlined a few species that had successfully survived over 2 weeks in space without any protection, whatsoever. But exactly how are they managing to do so? Are there any specific mechanisms that allow them to do so? If so, is there a possibility that these adaptive microbes could impact humans as well? Let’s find out!
A few species that have been tested in space previously! (Credit: Unknown)
It is almost inevitable that microbes would be present on any spacecraft that leaves Earth or comes back to Earth because humans themselves carry them. The idea is that this must be maintained at a healthy level and no new species gets carried back to our planet because we have no idea what kind of an impact they might have! In general, microbes that are in outer space can be separated into two classes: human flora and extremophiles. While human flora is the microbes that are already present in our body, extremophiles are the ones that can literally survive any condition. Be it outer space or a deep-sea vent, they’re there and they’re thriving!
Many of these studies have been done using the systems biology approach where they make use of complex mathematical models to get a picture of exactly how the molecules in these microbes are interacting with each other. This gives us an idea of what changes we can expect in them and how they come about.
Are there differences in their cellular behavior?
In previous studies on common virulent bacterial strains, it was found that when they are exposed to harsh conditions such as those in space, they become more virulent in nature. This means that their ability to infect and spread becomes a lot higher than they already have. This is due because the regulation of gene expression changes under hostile conditions and in order to survive the cells compensate in a way that helps them survive! This can also be seen from the fact that the lag phase (Where bacterial cells get used to their living conditions) is a lot shorter if they’re in space, meaning they can literally reproduce a lot faster!
Also, there are many other modifications that happen within the cell especially with respect to their metabolism. They become more active and tend to produce more secondary metabolites – helps them survive better in such conditions! Even within the cell membrane, they can rearrange their molecular structures in such a way that the space vacuum does not desiccate them, making them stronger, literally.
Antibiotic resistance in space?
Now that we’ve discussed that microbial species are more active in space, naturally, the next question that arises is how can we use it to our advantage? Well, they produce antibiotics a lot faster than they do on Earth! In some cases, production can be as high as 200% when compared to studies done on Earth. So does this mean now we have to produce all our antibiotics in space? Well, not really. The idea is to understand why antibiotic production ramps up under those conditions and how we can mimic them on Earth.
But again the question remains if they’re more resilient in space, does that mean they’re more resistant to antibiotics as well? The short answer is yes. When they tested the internal microbial flora of an astronaut, it was found that in a strain of E. coli the resistance to common antibiotics such as kanamycin and colistin were increased. This same phenomenon was observed in many other bacterial species which is quite worrying to think about. But when these same strains were tested back on ground laboratories, the effects were reversible. Even then, it raises many concerns over the health of the astronauts and cosmonauts that do go up there!
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Dey, D. (2019). Space Microbiology: Modern Research and Advantages for Human Colonization on Mars. International Journal for Research in Applied Sciences and Biotechnology, 6.
Milojevic, T., & Weckwerth, W. (2020). Molecular mechanisms of microbial survivability in outer space: a systems biology approach. Frontiers in Microbiology, 11, 923.
Liu, C. (2017). The theory and application of space microbiology: China’s experiences in space experiments and beyond. Environmental microbiology, 19(2), 426-433.