Evaluation of the fluids mixing enclosure system for life science experiments during a commercial Caenorhabditis elegans spaceflight experiment

Abstract

The Student Spaceflight Experiments Program (SSEP) is a United States national science, technology, engineering, and mathematics initiative that aims to increase student interest in science by offering opportunities to perform spaceflight experiments. The experiment detailed here was selected and flown aboard the third SSEP mission and the first SSEP mission to the International Space Station (ISS). Caenorhabditis elegans is a small, transparent, self-fertilizing hermaphroditic roundworm that is commonly used in biological experiments both on Earth and in Low Earth Orbit. Past experiments have found decreased expression of mRNA for several genes whose expression can be controlled by the FOXO transcription factor DAF-16. We flew a daf-16 mutant and control worms to determine if the effects of spaceflight on C. elegans are mediated by DAF-16. The experiment used a Type Two Fluids Mixing Enclosure (FME), developed by Nanoracks LLC, and was delivered to the ISS aboard the SpaceX Dragon and returned aboard the Russian Soyuz. The short time interval between experiment selection and the flight rendered preflight experiment verification tests impossible. In addition, published research regarding the viability of the FME in life science experiments was not available. The experiment was therefore structured in such a way as to gather the needed data. Here we report that C. elegans can survive relatively short storage and activation in the FME but cannot produce viable populations for post-flight analysis on extended missions. The FME appears to support short-duration life science experiments, potentially on supply or crew exchange missions, but not on longer ISS expeditions. Additionally, the flown FME was not properly activated, reportedly due to a flaw in training procedures. We suggest that a modified transparent FME could prevent similar failures in future flight experiments.

Studying Planarian Regeneration Aboard the International Space Station Within the Student Space Flight Experimental Program

“…However, compared to the air volume in the + air conditions, these bubbles are negligible and thus cannot explain why some -air conditions outperformed the + air conditions in the FME-tubes. The previously reported experiments with C. elegans similarly found that chance largely dictated whether the nematodes survived long-term storage in the FME tubes (Warren et al, 2013). Morokuma et al (2017) concluded that the optimal condition for 30-day survival of intact planarians at 20 • C was a 50-50 airto-water ratio and that using 100% water and no air resulted in complete lethality of intact planarians within 5 days.…”

“…Generally, such a long transportation time is not ideal for biological experiments. It has been previously emphasized that late loading and early retrieval are optimal to maximize organismal health for life science experiments conducted in space (Hughes-Fulford, 2004; National Research Council of the National Academies, 2011; Warren et al, 2013). Travel time was considerably shorter in the non-SSEP planarian ISS experiments, with launch occurring within 12-14 or 31 h for the Gorgiladze (2008) and Morokuma et al (2017) studies, respectively.…”

“…To the best of our knowledge, the results of only one biological SSEP experiment have been published (Warren et al, 2013). In this study, the authors used an earlier version of the FME minilab system with Caenorhabditis elegans to study the effect of the transcription factor DAF-16 on previously reported genomic expression changes induced by spaceflight in C. elegans.…”

“…In this study, the authors used an earlier version of the FME minilab system with Caenorhabditis elegans to study the effect of the transcription factor DAF-16 on previously reported genomic expression changes induced by spaceflight in C. elegans. While the study was unsuccessful, partially due to incorrect activation of the experiment in space, it established that nematode viability could be maintained in the FME system for a maximum of 3 weeks (Warren et al, 2013).…”

Worms in Space for Outreach on Earth: Space Life Science Activities for the Classroom

“…To facilitate this activity, learners can be directed to the Student Spaceflight Experiment Program, which provides details of past and ongoing experiments using NanoRacks hardware that has been used on-board the ISS (http://ssep.ncesse.org/about-ssep/). This also allows them to consider flying an actual experiment, for example, as done by a US High School student (Warren et al, 2013) and by Canadian Secondary School students (Graveley et al, 2018).…”