Caption Sarah Wallace (L), NASA microbiologist and Genes in Space-3 principal investigator, and Sarah Stahl (R), microbiologist, are seen in their Johnson Space Center lab with the in-flight sample from the Genes in Space-3 investigation. Credit Rachel Barry
For the first time ever, a team of researchers have collected and identified microbes without leaving the spacecraft.
The Genes in Space-3 team have completed the first-ever sample-to-sequence process entirely aboard the Soyuz spacecraft, which could aid in the ability to diagnose and treat astronauts ailments in real time.
The ability to sequence microbes could also lead to the identification of DNA-based life on other planets and could benefit other experiments aboard the orbiting laboratory.
To identify microbes the researchers must isolate the DNA of samples and amplify or make many copies of the DNA that can then be sequenced or identified.
The team collected the microbial and amplified them by Polymerase Chain Reaction (PCR) and then sequenced and identified the microbes.
As part of regular microbial monitoring, petri plates were touched to various surfaces of the space station. About a week later, they transferred cells from growing bacterial colonies on the plates into miniature test tubes, which has never previously been done in space. After the cells were successfully collected, the team isolated the DNA and prepared it for sequencing.
NASA astronaut Peggy Whitson conducted the experiment aboard the orbiting laboratory, with NASA microbiologist and the project’s Principal Investigator Sarah Wallace and her team watching and guiding her from Houston.
Hurricane Harvey though, threatened the ground team’s ability to guide the progress of the experiment.
When the Johnson Space Center became inaccessible due to dangerous road conditions and rising flood waters, the team at Marshall Space Flight Center’s Payload Operations Integration Center in Huntsville, Alabama, who serve as “Mission Control” for all station research, worked to connect Wallace to Whitson using Wallace’s personal cell phone.
Wallace offered support to Whitson, a biochemist, as she used the MinION device to sequence the amplified DNA. The data were downlinked to the team in Houston for analysis and identification.
“Once we actually got the data on the ground we were able to turn it around and start analyzing it,” Aaron Burton, a NASA biochemist and the project’s co-investigator, said in a statement. “You get all these squiggle plots and you have to turn that into As [Adenine], Gs [Guanine], Cs [Cytosine] and Ts [Thymine].”
Wallace said the As, Gs, Cs and Ts are the four bases that make up each strand of DNA and can tell the researchers what organism the strand came from.
“Right away, we saw one microorganism pop up, and then a second one, and they were things that we find all the time on the space station,” she said in a statement. “The validation of these results would be when we got the sample back to test on Earth.”
After the samples returned to Earth, the researchers completed biochemical and sequencing tests to confirm the findings from the Soyuz spacecraft. They also ran the tests multiple times to confirm the accuracy and finding that each result was the same on the ground as in orbit.
Genes in Space-1 marked the first time the PCR was used in space to amplify DNA with the miniPCR thermal cycler.
This was followed shortly after by Biomolecule Sequencer, which used the MinION device to sequence DNA. Genes in Space-3 married the two investigations to create a full microbial identification process in microgravity.
“It was a natural collaboration to put these two pieces of technology together because individually, they’re both great, but together they enable extremely powerful molecular biology applications,” Wallace said.
