January 11, 2021 - Podcast

Episode 76—Blowflies, and Alzheimer’s

Chemical weapons are banned by international treaty, but they are still occasionally used to kill or seriously injure people around the world. Researchers at IUPUI may have found an unlikely ally in detecting chemical weapons use: insects called blowflies that feed on feces and dead bodies. Blowflies are pretty much present in any environment, says Christine Picard, a molecular biologist at IUPUI. The flies collect "samples" from the field either by feeding on the bodies of humans or animals killed by chemical weapons, or by drinking water contaminated with chemical weapons or their byproducts. The IU researchers have developed tests to determine what species a fly has been feeding on and whether it was eating feces or dead bodies. Those tests could provide some hints (though not proof) about where a fly might have picked up the chemicals in its gut. Picard says collecting the flies is easy; you just lure them in with rotting meat. While Picard and her team’s research is in early stages, they have conducted proof-of-concept experiments by feeding blowflies on substances similar to chemical weapons that pose no danger to humans. The substances were detectable in blowflies' guts two weeks after the feedings, suggesting that wild blowflies could retain chemicals of interest in their bodies long after a suspected chemical attack. Researchers also learned that most real nerve agents break down more quickly than the chemicals they tested, meaning they would probably not last as long in the flies’ guts. However, when nerve agents break down, they leave behind new chemicals that are nontoxic and can last for years, so it would likely be these breakdown products, not the nerve agents themselves, that would be detected in flies. Researchers are now planning to conduct feeding experiments with nerve agent breakdown products.

In other news, Alzheimer’s disease is the sixth leading cause of death in the United States and research has shown it might be ranked higher. While there is no cure for Alzheimer’s, IU researchers are studying whether the social connectedness of older adults may slow the progression of Alzheimer's disease. A team, led by social neuroscientist Anne Krendl, is focusing on social cognitive abilities -- the skills we need to maintain social relationships -- and the part of the brain that supports them. These abilities include the ability to understand the way other people think and feel, the ability to remember faces and other information about people, recognizing the differences between yourself and others, and adjusting for that. Research has shown that older adults whose social connections include a wide and varied circle of friends and acquaintances are less likely to experience cognitive decline than those with smaller, tightly knit networks. Social networks typically get smaller as people age. Older adults more often keep close ties with family members, leaving behind a broader circle of friends and acquaintances which could leave them more vulnerable to Alzheimer's disease. Krendl and her team hope to find out what is it about wider social relationships that specifically helps to stave off the onset of Alzheimer's disease. By studying the dynamic between the brain, social cognition, social networks and cognitive ability, Krendl and her team ultimately seek new ways of slowing down the progression of Alzheimer's.