Fruit fly researchers published thousands of papers in 2014, and several of them were picked up by the media. I even reviewed a couple of these popular stories on this blog. In April, the Seghal lab published a paper showing that sleep loss in young flies led to abnormal brain development and behavioral deficits in adulthood. In September, researchers in the Walker lab showed that increasing the levels of a molecule called AMPK in the guts of fruit flies could extend their lifespan, providing hope that we may one day be able to develop a pill to slow aging.

The most heartwarming story of 2014 came out in June, after a sixth-grader’s science fair project was published in the peer-reviewed journal PLoS One. Father and son worked together to discover that the artificial sweetener Truvia is toxic to fruit flies. Erythritol, the main ingredient of Truvia, is safe to consume for humans but quickly kills these winged pests. The researchers who worked on the project are now pursuing the possibility of using erythritol as a safe insecticide for fruit flies and other insects.

But perhaps the biggest news from 2014 involves flies… in space! Although many animals have been to space over the past several decades, fruit flies have recently proven to be ideal for studying the effects of zero gravity on earthly bodies. It’s widely known that microgravity (zero gravity) leads to rapid loss of bone density and muscle weakness, which is why astronauts spend a lot of time exercising while they’re in space. But did you know that microgravity also negatively affects the cardiovascular and immune systems? NASA recently announced a plan to send humans to Mars by 2030, but first, they need a better understanding of the long-term effects of microgravity on the body.

This fruit fly is covered with a fungal infection after its immune system was compromised by 2 weeks in space. Image credit: Deborah Kimbrell/UC Davis

Space flies made the news in January 2014 after the results of a successful experiment were published in PLoS One by the Kimbrell lab. Researchers sent flies into space for 12 days to determine how zero gravity affects their immune system. It may seem like a short trip, but that’s about half the lifespan of your average fly (roughly the equivalent of sending a human into space for 40 years!). The researchers reported that flies subjected to microgravity had reduced ability to fight off a fungal infection compared to their earthbound brethren. Also interestingly, flies exposed to hypergravity (even stronger than Earth’s gravity) showed an increased ability to fight off the infection. The difference in immunity was caused by changes in the Toll pathway, an immune response which is also present in humans and other mammals. These promising results provided a leap forward in understanding how astronauts’ immune system may also be affected by microgravity.

Three more fruit fly experiments were launched into space in 2014. In April, a collaborative group led by Dr. Peter Lee sent flies into space for 30 days to study the effects of microgravity on the cardiovascular system (the experiment was named The HEART FLIES study). The second experiment was launched in September by a team at NASA’s Ames Research Center led by Dr. Sharmila Bhattacharya. The researchers hope to better understand how flies adapt to microgravity by studying changes in behavior.

The final experiment, launched in December 2014, was the maiden voyage of NASA’s newly-developed Fruit Fly Lab-01 project. NASA’s Fruit Fly Lab is a collaborative effort with a sophisticated set-up that researchers hope will improve our understanding of how spaceflight affects immune function. After 30 days in space, researchers will analyze the immune systems from three generations of flies exposed to various levels of gravity.

The results of these three missions should be published this year. Researchers at NASA are hoping that the findings will help them predict the physical challenges that astronauts will face during future space exploration, including the first human mission to Mars. NASA is also planning yearly sequels to their Fruit Fly Lab’s debut mission, so stay tuned!

References:

• Baudier K.M., Nirali Patel, Katherine L. Diangelus, Sean O’Donnell & Daniel R. Marenda (2014). Erythritol, a Non-Nutritive Sugar Alcohol Sweetener and the Main Component of Truvia®, Is a Palatable Ingested Insecticide, PLoS ONE, 9 (6) e98949. DOI: http://dx.doi.org/10.1371/journal.pone.0098949
• Taylor K., Michael D. George, Rachel Morgan, Tangi Smallwood, Ann S. Hammonds, Patrick M. Fuller, Perot Saelao, Jeff Alley, Charles A. Fuller & Deborah A. Kimbrell (2014). Toll Mediated Infection Response Is Altered by Gravity and Spaceflight in Drosophila, PLoS ONE, 9 (1) e86485. DOI: http://dx.doi.org/10.1371/journal.pone.0086485
• NASA.gov