Researchers in the Raman Lab at UW recently published a study discussing sending microbes into space at the International Space Station to evaluate how mutations induced by microgravity may impact human health by utilizing the bacteria Escherichia coli and the phage T7 Bacteriophages.
Phages, like the T7 Bacteriophage, work by preying on and then invading bacteria, where they can hijack the DNA and replication mechanisms to make proteins and enzymes which help the phage multiply, associate professor in the Department of Bacteriology Garret Suen said.
“The protein and enzymes that result from [invasion] will be used to force the bacteria to produce other copies of themselves,” Suen said.
Work in the field of bacteriophage and how they evolve isn’t a new topic, associate professor in the Department of Biochemistry Srivatsan Raman said.
There is a constant arms race between bacteriophage and bacteria where they mutate to compete against each other, according to Raman. The race occurs because as bacteria develop antibiotic resistance to treatments, phages find other ways to kill the bacteria, Raman said.
“Bacteria have become resistant to all kinds of antibiotics and we’ve been interested in figuring out how bacteriophages could be deployed as alternative therapies to kill high drug resistant bacteria,” Raman said.
Prior to sending the E. coli bacteria and the T7 Bacteriophage into space, the Raman Lab faced a few constraints and concerns, according to Raman. These included a lack of physical space, because all samples of the bacteria and phage had to fit in a small box, approximately the size of a lunch box.
First, the researchers had to ensure that all biosafety conditions that occur on earth would occur on the International Space Station, according to Raman. Second, there is a lack of experiments that the astronauts could do due to training and space, Raman said they opted to perform simple experiments such as temperature changes and shaking the samples.
“We had to run mock versions of those experiments on Earth,” Raman said. “If [we were] going to take the trouble of sending these samples up, we’ll get some interpretable data that we can use.”
Mutations of both bacteria and bacteriophages can impact human health in a positive, negative or neutral way, Suen said. One mutation can have different effects for different groups. For example, antimicrobial resistance is good for bacteria, but may not be beneficial for phages or humans, according to Suen.
Microbes undergo stress in a multitude of ways every single day, such as a lack of oxygen, high salt concentration, extreme temperature or competition with other microbes, but they are able to adapt.
“These microbes have never experienced [space], they’re adapting just like we as humans are,” Suen said.
Adaptations from space found infections proceeded much slower in Raman’s study. The researchers hypothesized that this was because the liquid mixture that the phages and bacteria are mixed into have different properties in space, so it took longer for phages to infect and replicate in bacteria, according to Raman.
On earth, it takes about 20 minutes for infection and replication to occur. But, in the experiments conducted in space the replication time took significantly longer. Periods of infection and replication could be anywhere from hours to days long, rather than minutes, impacting the microbiome which is a part of the human body, Raman said.
“This has implications in terms of how does the microbiome composition change over time,” Raman said.
Bacteriophages and bacteria both experienced positive mutations while in space, due to microgravity, according to Raman. The adaptation to microgravity is a response to high stress, similar to salt concentration, pH and temperature, according to Raman.
Mutations that are picked up from phages and bacteria often help with keeping them intact by supporting the membrane, Raman said.
“Evolution happens in the international space station as well,” Raman said.
Virulence, the ability of a microorganism to cause disease were analyzed when the samples returned to Earth by testing how phages were able to kill pathogenic bacteria that causes urinary tract infections, according to Raman. The mutated phages were highly effective at killing those pathogens, which could have implications in the fight against drug resistance in bacteria.
Despite the fact that these mutations occurred in space, there is optimism that this study can be beneficial from a human health standpoint, Raman said.
“We can take these natural phages that occur on Earth. We can make modifications to them and we could repurpose them as therapeutic agents against bacterial diseases. That was quite a cool finding,” Raman said.
While the publication of this study provides strong conclusions, the information found acts as a flood gate for questions, as there are relatively few answers compared to the questions posed, opening the door for more complex studies in the future, according to Raman.
