The fruit fly — Drosophila melanogaster — is helping researchers understand how spaceflight affects the immune system's response to infection. (Credit: NASA/Dominic Hart)

The most advanced system to date for studying fruit flies in space, NASA's Fruit Fly Lab, is making its debut aboard the International Space Station. The Fruit Fly Lab-01 mission, planned to launch to the station in December aboard SpaceX's fifth commercial resupply services (CRS) mission, is the first of a series of fruit fly investigations NASA plans to conduct.

The fruit fly — a widely studied biological research model — plays a lead role in this study and will help us better understand how spaceflight impairs the body's ability to fight infections. Model organisms, such as fruit flies, are simpler and easier to research than humans. Their study can shed light on the mechanisms of human health and disease because we share the basic biochemical machinery of life. Fruit flies can fill in for humans in this research because the insect's immune system closely resembles human innate immunity — our first line of defense against infections.

Lights built into the system will create an Earth-like day/night cycle for the flies and cameras record high-definition video of fly behavior, which can indicate their health. Artificial gravity, generated by the NanoRacks Astrium centrifuge, will allow researchers to distinguish the effects of weightlessness from other aspects of spaceflight, such as radiation and launch forces. The centrifuge can simulate the levels of gravity found on Earth, the moon and Mars.

This investigation follows on the heels of other spaceflight fruit fly studies. However, none of the previous hardware systems had the combined capabilities of artificial gravity, day/night lighting, video observation, tissue preservation and the ability to separate multiple generations of flies. The system's new tools for in-flight preservation of fruit fly tissue can be used for studies of gene expression, such as those that will be performed by NASA's GeneLab.

Fruit Fly Lab can support longer-duration studies in space than were previously possible. Multiple generations of space-reared fruit flies can be bred continuously with sufficient hardware and food.

"At the end of the 28-day validation mission we expect to be studying the children, grandchildren and possibly great-grandchildren of the original population of fruit flies that are launching aboard SpaceX CRS-5," said Sharmila Bhattacharya, director of the Biomodel Performance and Behavioral Laboratory at NASA's Ames Research Center in Moffett Field, California, and project scientist for the mission.

An immune response study will be conducted during the mission, major goals of which are to show that the system operates smoothly aboard the station and delivers high-quality data.

"Data from this validation study will confirm and extend findings from shorter-duration studies we conducted aboard the space shuttle that examined how spaceflight impacts fruit fly immune responses," said Bhattacharya. "We are conducting a host-pathogen study involving immune challenge in orbit where both the flies and the bacteria are under the influence of spaceflight."

During spaceflight microbes can become more infectious and the immune systems of complex organisms such as humans and fruit flies can weaken. Bhattacharya's team at Ames is studying the underlying biological mechanisms responsible for this diminished immune response in the host organism. Such knowledge can be applied to protecting human health, including the health of astronauts who will someday travel deeper into space than ever before, such as on a journey to Mars. 

Each fly cassette — a food-containing habitat for fruit flies — fits inside of a camera and lighting unit that records high-definition video and provides a day/night cycle for the flies. (Credit: NASA/Dominic Hart)

Groups of flies will be transported to the space station in habitats known as fly cassettes. Half of the flies will be weightless during the study and half will be exposed to simulated Earth gravity. The crew will periodically feed the flies and preserve samples of fruit fly tissues for analysis by Bhattacharya's team.

Some of the flies' food will contain a microbe that will infect the insects. The researchers will compare the ability of fruit flies to resist infection by the food-borne microbe between the flies that were weightless, those exposed to simulated Earth's gravity in space and flies that remained on Earth.

Once the Fruit Fly Lab-01 study completes, the Fruit Fly Lab research platform will be made available for proposed spaceflight research from the scientific community. NASA anticipates a series of yearly sequels to follow the debut mission.

(Courtesy of NASA)

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