Space-Raised Flies Unable to Fight Off Fungal Infections

Posted on January 27, 2014

Drosophila infected with fungus after returning from space

Flies sent as eggs on a 12-day mission on the Space Shuttle Discovery were unable to fight off fungal infection as adults. A sick looking Drosophila infected with fungus is pictured above. The research study was led by Deborah Kimbrell, a researcher in the Department of Molecular and Cellular Biology in the UC Davis College of Biological Sciences.

The flies developed into adults on the tenth day of their 12-day mission in space. They were tested by Kimbrell and her colleagues when they returned to Earth. The fruit flies were exposed to two different types of infections: a fungus, which flies fight off through a pathway mediated by the Toll receptor, and a bacterial infection that flies resist through a gene called Imd.

The flies fought off the bacterial infection but were unable to fight off fungal infections. Scientists say the Toll pathway was "non-functional" in space-raised flies leaving them vulnerable to the fungus.

The scientists also conducted Earth-based experiments in a centrifuge under hypergravity conditions and found fruit flies showed improved resistance to the fungus.

The research was published here in PLoS One. In the paper, the researchers say, "Our major findings are that hypergravity and spaceflight have opposing effects, and that spaceflight produces stress-related transcriptional responses and results in a specific inability to mount a Toll-mediated infection response."

Photo: Deborah Kimbrell/UC Davis

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