Research: Add space salad to the risks astronauts face

Jan 22, 2024

3 min

Harsh BaisKali Kniel


University of Delaware researchers grew lettuce under conditions that imitated the weightless environment aboard the International Space Station and found those plants were actually more prone to infections from Salmonella. 


It’s been more than three years since the National Aeronautics and Space Administration made space-grown lettuce an item on the menu for astronauts aboard the International Space Station. Alongside their space diet staples of flour tortillas and powdered coffee, astronauts can munch on a salad, grown from control chambers aboard the ISS that account for the ideal temperature, amount of water and light that plants need to mature.


But as the UD researchers discovered, there is a problem. The International Space Station has a lot of pathogenic bacteria and fungi. Many of these disease-causing microbes at the ISS are very aggressive and can easily colonize the tissue of lettuce and other plants. Once people eat lettuce that’s been overrun by E. coli or Salmonella, they can get sick.


With billions of dollars poured into space exploration each year by NASA and private companies like SpaceX, some researchers are concerned that a foodborne illness outbreak aboard the International Space Station could derail a mission.


In the new study by UD's team, published in Scientific Reports and in npj Microgravity, researchers grew lettuce in a weightless environment similar to that found at the International Space Station. Plants are masters of sensing gravity, and they use roots to find it. The plants grown at UD were exposed to simulated microgravity by rotation. The researchers found those plants under the manufactured microgravity were actually more prone to infections from Salmonella, a human pathogen.



Stomata, the tiny pores in leaves and stems that plants use to breathe, normally close to defend a plant when it senses a stressor, like bacteria, nearby, said Noah Totsline, an alumnus of UD’s Department of Plant and Soil Sciences who finished his graduate program in December. When the researchers added bacteria to lettuce under their microgravity simulation, they found the leafy greens opened their stomata wide instead of closing them.


“The fact that they were remaining open when we were presenting them with what would appear to be a stress was really unexpected,” Totsline said.


Totsline, the lead author of both papers, worked with plant biology professor Harsh Bais as well as microbial food safety professor Kali Kniel and Chandran Sabanayagam of the Delaware Biotechnology Institute. The research team used a device called a clinostat to rotate plants at the speed of a rotisserie chicken on a spinner.


“In effect, the plant would not know which way was up or down,” Totsline said. “We were kind of confusing their response to gravity.”


Additionally, Bais and other UD researchers have shown the usage of a helper bacteria called B. subtilis UD1022 in promoting plant growth and fitness against pathogens or other stressors such as drought.


They added the UD1022 to the microgravity simulation that on Earth can protect plants against Salmonella, thinking it might help the plants fend off Salmonella in microgravity.


Instead, they found the bacterium actually failed to protect plants in space-like conditions, which could stem from the bacteria’s inability to trigger a biochemical response that would force a plant to close its stomata.


“The failure of UD1022 to close stomata under simulated microgravity is both surprising and interesting and opens another can of worms,” Bais said. “I suspect the ability of UD1022 to negate the stomata closure under microgravity simulation may overwhelm the plant and make the plant and UD1022 unable to communicate with each other, helping Salmonella invade a plant.”


To contact researchers from the team, visit the profiles for Bais or Kniel and click on the contact button.

Connect with:
Harsh Bais

Harsh Bais

Professor, Plant and Soil Sciences

Prof. Bais conducts research in plant signaling – how plants recognize and communicate with one another.

Plant-Microbe InteractionsPlant BiologyPlant SignalingRoot ExudationPlant and Soil Sciences and Horticulture
Kali Kniel

Kali Kniel

Professor, Microbial Food Safety

Prof. Kniel’s laboratory explores issues of food safety and public health that involve transmission of viruses and pathogenic bacteria.

Food SystemsPathogenic BacteriaFood Safety Public HealthMicroorganisms
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UD English professors reveal 2026 beach reads, tying summer picks to big themes in today’s culture featured image

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When summer rolls around, the best beach reads do more than just pass the time—they somehow capture what everyone’s talking about right now. That’s the vibe behind University of Delaware’s professor-picked list: books that are fun to sink into, but also surprisingly sharp about the world we’re living in. Think big feelings, messy relationships, culture shifts, and the kind of stories that make you look up from the page and go, “Yep, that tracks.” "There Is No Antimemetics Division" By qntm A Reddit novel turned print bestseller, "There Is No Antimemetics Division" is a surreal horror story that follows an X-Fileish government division fighting aliens whose battlefield is the human mind. How do you fight an enemy whose existence you cannot remember? – Siobhan Carroll, Associate Professor "The Briar Club" By Kate Quinn I'm a big fan of Kate Quinn. Her books never disappoint. Her writing is wonderful and captivating, and the voices and characters are authentic. This book, set in the 50s, is a post-war reflection on a group of tenants in a boarding house who, over food (recipes included!), become friends and navigate McCarthyism, conspiracies and fear. It is historical fiction written to remind us that history repeats itself. – Christine Cucciarre, Professor "Guido Brunetti mysteries" By Donna Leon I've gotten completely hooked on these mysteries set in Venice. Fans will tell you the best is the fifth book in the series, "Acqua Alta," but be sure you read the first book to meet the characters! – Emily S. Davis, Director of Graduate Studies "When We Cease to Understand the World" By Benjamin Labatut An English professor recommending a book detailing the lives of physicists, scientists and mathematicians? Yes! History, heady concepts, madness, melancholy and beautiful prose come together in a haunting way. – Viet Dinh, Associate Professor "Dungeon Crawler Carl series" By Matt Dinniman What if you smushed role-playing video games/tabletop games with The Running Man? Plus, there's a sassy cat who talks! – Lowell Duckert, Associate Professor "Just Kids" By Patti Smith I've recently read "M Train" by Patti Smith, and now I'm looking forward to reading the book for which she won the National Book Award. Smith's memoirs can be impressionistic, but they often come down to some unexpected detail or some ongoing longing. If you know her music, you can sometimes hear it in the background, or you can spot those moments in her life when music would almost necessarily emerge as a great force gathered by her authentic approach to life. She's one of those writers who can change how you look for and find what most matters to you, how you look for and embrace your own soul. – John Ernest, Chair in English "Prairie Fires: The American Dreams of Laura Ingalls Wilder" By Caroline Fraser I loved reading the "Little House" books as a child. It seemed like a life full of adventure and love, even through "The Long Winter." But this biography of author Laura Ingalls Wilder reveals a life full of struggle and loss behind the calico dresses and the fiddle lullabies. Caroline Fraser won the 2018 Pulitzer Prize for "Prairie Fires," using unpublished manuscripts, letters, diaries, and land and financial records to pull back the pioneer spirit curtain and show readers the reality of life on the prairie. – Dawn Fallik, Associate Professor "The School for Good Mothers" By Jessamine Chan Warning: Do not bring this book to the beach without plenty of sun screen, because you will not put it down and that might make YOU a candidate for enrollment in The School. Second Warning: The book is compelling precisely because it will make you mad and freak you out. My wife gave it to friends as a Mother's Day present, and every mother who read it could relate. – Peter X Feng, Associate Professor "Audition" By Katie Kitamura This book has been on my bedside table for months now, just waiting for the semester to end. 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Perfect for a day at the beach. Best of all, if you fall in love with the characters and the place, it's part of a series of three books, so you can keep going! – Cathryn Molloy, Professor "The Order of Time" By Carlo Rovelli You could read any Rovelli book, really—I am reading the one on the birth of science at the moment— but this is the one that drew me in. He merges a physics/science‒centered approach to time with a human/experienced‒centered view of it, which I just cannot get enough of. It is beautifully written, at times verging on poetic, while also bringing in a lot of the information and knowledge I seem to have skipped over as a terrible science student. It's joyful and intense and meditative. And yes, this is what I read for fun! – Amish Trivedi, Assistant Professor "The Season of Styx Malone" By Kekla Magoon Two young Black boys in small-town Indiana fall under the spell of Styx Malone, a mysterious new kid who arrives for the summer and stirs things up by persuading them to pursue their biggest dreams and breaking a few rules along the way. I collect multicultural kids books and stumbled across this one six years ago. It captured me because it celebrates family and friendship, depicts young people with rich interior lives, and mixes in a little mystery and humor. There's something sweet and down-home about it. It's a refreshing little respite from, well, everything ... – Délice Williams, Associate Professor To speak to the professors more about what makes these books the perfect summer reads, email mediarelations@udel.edu.

New clues about how earthquakes work featured image

4 min

New clues about how earthquakes work

University of Delaware researcher Jessica Warren helped uncover evidence that sections of fast-moving underwater faults may act like “brakes,” controlling the occurrence of big earthquake events on transform faults. Warren can discuss what the findings, released today in the journal Science, mean for earthquake science and future modeling. Situated along a stretch of the equator in the Pacific Ocean, between Indonesia and Central America, the Gofar transform fault is one of the fastest moving faults on Earth — cruising along the seafloor at about 140 millimeters per year. This is over four times faster than the San Andreas fault is moving in California. “Geologically speaking, it's like looking at a moving Acela train next to a SEPTA train on the tracks,” said Warren, a professor of earth sciences at UD. Researchers know that the Gofar transform fault line has experienced a magnitude 6 earthquake about every five to six years over the last three decades. 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Warren: Geoscientists want to understand faults and earthquakes because they are obviously a big hazard on land. The rocks that make up the seafloor are simpler than those found on land, providing a more controlled space to study earthquakes, despite the challenges of doing research underwater. If you want to understand how faults build up stress and then release it (and where), the Gofar transform fault is amazing, because it experiences earthquakes at reliable intervals of five to six years. This is a lot more regular than any other fault. In 2019, I led a research cruise on the R/V Atlantis that deployed 51 seismometers two miles down on the seafloor to detect these small events. We were able to compare the results of our measurements from 2019 to 2020 to an experiment conducted by my colleague Jeff McGuire on the same fault in 2008. The similarities in the two datasets brought us to the realization that fault sections without large magnitude earthquakes control the overall occurrence of big events on transform faults. When we had that observation in 2008, that might have been a one-off, but getting back this new data and seeing such similar behavior was a new insight into what's happening in the fault. How does that tell you about how earthquakes occur on land? Warren: On land, people spend a lot of time looking at how rainwater and groundwater move in a fault system, and how that influences the behavior of the fault. In the oceans, we have an unlimited amount of water. Once the rock cracks, the water is going to get in there. Being able to look at how a fault changes through the earthquake cycle — which we've now measured most of on this one fault — can help us understand what is universal about how faults work, and how rock friction works. And one of the big players is water. That's why the rock samples that my lab works on matter. Fault structure is another thing that we've been trying to understand. We know from on land that some parts of a fault are linear, while other parts have lots of strands and maybe contain more fractures and that, if you start putting water in the picture, this can limit or change how water moves into the system. Now, we have these very high-resolution maps of the seafloor, where we can see, for the first time, where the fault itself is. One of the next things we want to understand is how fluid gets into the fault, and then how friction in a fault changes when water is there. Why is this important? Warren: The next step is to translate the understanding that we've gained from this specific fault to understanding how faults behave in general. This is the longer path to really understanding earthquake hazards. It's not going to change our hazard models tomorrow, but hopefully it will in the decades to come. To reach Warren directly and arrange an interview, visit her profile and click on the "contact" button. Interested reporters can also email MediaRelations@udel.edu.

Survey says: Senior leaders are using AI, but they could use more direction featured image

4 min

Survey says: Senior leaders are using AI, but they could use more direction

Over the years, study upon study has shown that senior leaders are slower to adapt to new technology – email, the Internet and social media – than younger employees. That’s not necessarily so with AI, according to the University of Delaware’s Saleem Mistry. Mistry, associate professor of management at UD's Alfred Lerner College of Business & Economics, recently conducted a survey of more than 200 university alumni, 75% of which had more than 16 years of professional experience. He found that senior leaders are actively adopting AI to solve their biggest challenges. However, they are doing so largely without structured support or guidance. Here are four findings from Mistry's survey that shows how AI is actually being used at the top. Senior Leaders Are Overwhelmingly Self-Taught Mistry said his most glaring finding is the gap between high AI adoption among senior leaders and the near-total absence of formal corporate support. Although a majority use these tools, they are almost entirely self-taught, which highlights visible opportunity that organizations aren’t really steering the AI conversation for leaders: • High usage. 62% of all senior leaders surveyed use AI tools "regularly" or "occasionally" in their work. • Training gap. Of those users, an overwhelming 80% report their organization provides "Never" or only "Sometimes" (mostly never) adequate training. Mistry said this shows that leaders from VP level down are using tools like ChatGPT and Copilot informally to keep up with heavy workloads, without any real organizational guidance. The stakes are high. In the survey, a vice president of legal was using AI for compliance tasks and a manager of three was using it for performance reviews, both with no formal training. “These are senior leaders handling sensitive work while essentially figuring it out on their own,” Mistry said. There is a clear ladder of AI use Leaders are not using AI randomly. There is a clear progression in how they use it, moving through three levels. • Tier 1 (The Drafters) This is the most common starting point. Leaders use AI to improve writing and communication. They draft emails, shape documents, and refine tone. As one Director of Product put it, it helps him "polish phrasing" and adjust tone and voice. • Tier 2 (The Synthesizers) At this stage, leaders use AI to manage information overload. They summarize meetings, condense documents, and pull together research so they can keep up with large volumes of input. As one leader managing a team of 200 said, "Being a leader requires attention in a variety of areas. AI helps me manage the vast amounts of information I need to consume." • Tier 3 (The Architects) Here, leaders move beyond writing and summarizing. They use AI to automate parts of their work. This includes building agents, creating custom GPTs, or designing tools that track work and performance. One leader managing 300 people said, "It will eliminate half or more of my overhead." Managers and individual contributors use AI for different reasons People managers and individual contributors (IC) are using AI for very different reasons based on their roles. • For people managers, their main challenge is scale. They are overloaded with communication and administration, so they use AI to reduce noise and keep up. They lean heavily on summarization and tone adjustment tools. • For project leads and ICs, their focus is output. They use AI to produce work faster, including drafting content, building decks, writing code, or generating ideas. This difference reflects their jobs. One group is trying to keep up, the other is trying to produce more. It also shows that AI is not a single-use tool. Its value depends on the problem it is being used to solve. This difference reflects their jobs. One group is trying to keep up, the other is trying to produce more. It also shows that AI is not a single-use tool. Its value depends on the problem it is being used to solve. Resistance to AI is mostly intentional Among the 38 percent of leaders who do not use AI, resistance is usually not based on lack of awareness. It falls into three groups: • The Ethical Objectors. Some avoid AI due to concerns about its broader impact. • The Quality Skeptics. Some do not trust the output and feel it is not reliable enough for important work. • The Blocked. Some are not allowed to use AI due to company policy. Mistry concludes that there is a clear overall pattern: Leaders are using AI in practical ways, but mostly without structured support or guidance. “If it feels like you are figuring this out as you go without much help from your organization, that is consistent with what most leaders are experiencing,” Mistry said. To connect directly with Mistry and arrange an interview, visit his profile page and click on the "connect" button. Interested reporters can also email MediaRelations@udel.edu.

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