Researchers find key to stopping deadly infection

Disabling a critical cellular pathway reveals potential treatment for rotavirus and some other infections

WashU Medicine

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New research from WashU Medicine identified a key enzyme, called FA2H, that enables rotavirus to infect cells. When rotavirus enters a cell without FA2H, it becomes trapped in pockets called endosomes (indicated by red arrows). This prevents the virus from infecting the rest of the cell.

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Credit: DING LAB

Rotavirus causes severe dehydrating diarrhea in infants and young children, contributing to more than 128,500 deaths per year globally despite widespread vaccination efforts. Although rotavirus is more prevalent in developing countries, declining vaccination uptake in the United States has resulted in increasing cases in recent years.

New research from Washington University School of Medicine in St. Louis has identified a key step that enables rotavirus to infect cells. The researchers found that disabling the process in tissue culture and in mice prevented infection. This discovery opens up new avenues for therapeutic intervention to treat rotavirus and other pathogens that rely on the same infection mechanism.

The results were published in PNAS.

“Rotavirus kills infants and children, young people who never had a chance at life,” said Siyuan Ding, PhD, an associate professor of molecular microbiology at WashU Medicine. “That’s why we want to develop effective therapeutics, even though we already have vaccines that we can use. Not all kids receive the vaccine, and this virus is very infectious. Once a child has the virus, there’s currently no treatment; we can only manage the symptoms.”

Enzyme as entry code

To identify a possible treatment, Ding and his collaborators focused on features of the body’s cells that can be leveraged to protect against viral infection. This strategy, Ding said, may be less likely to trigger drug resistance than targeting the virus itself and has the potential to work on multiple diseases because it is based on shared infection routes, not disease-specific traits.

When a rotavirus particle burrows through the outer wall of a cell, it isn’t immediately free to infect the cell. Instead, the virus emerges inside a tiny cell compartment called an endosome.

The researchers identified an enzyme in cells, called fatty acid 2-hydroxylase (FA2H), that is essential to rotavirus breaking out of endosomes and fully infecting cells. Using advanced gene editing techniques, they removed the FA2H gene from human cells and found that viruses remained trapped in endosomes and could not replicate effectively. In other words, disabling FA2H prevented infection from the very beginning.

To confirm these results in animal models, the researchers created genetically modified mice specifically missing the FA2H enzyme in the cells lining the small bowel. These mice showed significantly fewer symptoms when infected with rotavirus compared to normal mice, demonstrating the importance of FA2H in viral infections.

Unlike vaccines that typically cue the body to produce antibodies that block pathogens from entering cells in the first place, disabling FA2H intervenes in the normal course of infection to craft a complementary line of host-based cellular defense against rotavirus and similar infections.

“Viruses are dependent on hosts, so we’re preventing infection by stopping them from using the host’s machinery,” Ding said. “We didn’t really know how this enzyme, FA2H, worked until this study, but now we’re seeing that the same process aids other pathogens, such as Junín virus and Shiga toxin, suggesting a common ‘entry code’ used by multiple disease-causing agents.”

Now that Ding and his collaborators have identified this pathway as a broadly exploitable entry mechanism, they can start testing drugs that duplicate the effect of FA2H gene editing.

Li E, Zang R, Kawagishi T, Zhang W, Iyer K, Hou G, Zeng Q, Meganck RM, Ross SR, Wang X, Su X, Ding S. Fatty acid 2-hydroxylase facilitates rotavirus uncoating and endosomal escape. PNAS. September 3, 2025. DOI: https://www.pnas.org/doi/10.1073/pnas.2511911122

This work is supported by NIH R01 AI150796 and R01 AI159290. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

About Washington University School of Medicine

WashU Medicine is a global leader in academic medicine, including biomedical research, patient care and educational programs with more than 3,000 faculty. Its National Institutes of Health (NIH) research funding portfolio is the second largest among U.S. medical schools and has grown 83% since 2016. Together with institutional investment, WashU Medicine commits well over $1 billion annually to basic and clinical research innovation and training. Its faculty practice is consistently among the top five in the country, with more than 2,000 faculty physicians practicing at 130 locations. WashU Medicine physicians exclusively staff Barnes-Jewish and St. Louis Children’s hospitals — the academic hospitals of BJC HealthCare — and Siteman Cancer Center, a partnership between BJC HealthCare and WashU Medicine and the only National Cancer Institute-designated comprehensive cancer center in Missouri. WashU Medicine physicians also treat patients at BJC’s community hospitals in our region. With a storied history in MD/PhD training, WashU Medicine recently dedicated $100 million to scholarships and curriculum renewal for its medical students, and is home to top-notch training programs in every medical subspecialty as well as physical therapy, occupational therapy, and audiology and communications sciences.

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2511911122 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Fatty acid 2-hydroxylase facilitates rotavirus uncoating and endosomal escape

Leafcutter ants have blind spots, just like truck drivers

Scientists at the Smithsonian Tropical Research Institute (STRI) in Panama discovered that carrying oversized loads limits the ability to perceive the trail in leafcutter ants, akin to blind spots while we are driving

Peer-Reviewed Publication

Smithsonian Tropical Research Institute

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Blind Spots in Leafcutter ants

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Credit: Smithsonian Tropical Research Institute

We have all been in that situation: the moving boxes are large and heavy, but we are determined to carry them all in one trip, even if that means we can’t see where we’re going. In the tropics, some leaf-cutter ants face a similar challenge: carrying a load that is several times their body weight. To make matters even more difficult, scientists at the Smithsonian Tropical Research Institute (STRI) in Panama recently discovered that carrying oversized weights may create “blind spots” when leafcutter ants transport material on a trail.

Leafcutter ants live in societies, and just like humans, deal with waste management, diseases, road design and the everyday struggle of many cities: traffic. Interestingly, some leaf-cutter ants can carry leaves that are eight times their body weight. However, when leafcutter ants carry an oversized load, they walk more slowly, delaying the nestmates behind, just as big trucks do on a highway. This phenomenon, known as "the truck-driver effect," can reduce the walking speed of following ants by up to 50 percent. The reason behind this phenomenon was still a mystery. Staff scientist Sabrina Amador and her intern Katherine Porras video-recorded ants with and without leaves to see how they used their antennae. In ants, the antennae are in charge of touching, smelling and tasting. Then, they measured the ants and the leaves. They also performed an interesting experiment: They offered artificial leaves to the ants, consisting of tiny pieces of paper previously dipped in orange juice. This makes the paper attractive to the ants. Once an ant collected an artificial leaf, they carefully cut it with scissors while the ant was still walking, to reduce the load in half, and checked the use of antennae before and after reducing the load.

“When I started observing the ants, what I enjoyed most was paying attention to the small details. The more I observed them, the more questions I had. Then I realized that, with any organism we study, the most beautiful thing about science is that we never stop learning,” says Porras.

By carefully watching the videos, they discovered that ants with leaves performed fewer antennae taps per step than ants without leaves. Also, the ants increased their antennae taps when scientists reduced the load in half. Because ants follow their trail by "feeling” with their antennae the chemicals other ants leave, and carrying an oversized load limits the ability of ants to tap the ground, the ants present difficulties to perceive the trail accurately. Therefore, carrying larger loads might lead to difficulties in dealing with trail obstacles or surface irregularities. Interestingly, this effect is stronger in larger ants, just as if they were larger trucks.

“What we discovered may explain why, despite having the strength to move larger loads, some ants choose to carry smaller ones,” Sabrina explained. “Leaf-cutting ants are experts at solving logistics and transportation problems, and now we understand more about their load-lifting capacity. As humans have dealt with similar problems, we could learn valuable lessons from their efficiency strategies”, says Amador.

Leafcutter ants enrich the soil and disperse seeds, playing a vital role in America's tropical forests. Remarkably, leafcutter ants can harvest around 1-2 tons of plant material per year. Studying their foraging behavior helps us understand how they navigate the forest, orient back to their nest, or deal with obstacles while carrying plant material. But it also provides insights into how foraging could influence the rate of plant material collection and its broader effects on nutrient cycling and forest dynamics. Ant movements and their efficiency have also inspired the construction of different robots, and their study deserves further attention in the future.

 

Reference: Porras-Brenes, K., & Amador-Vargas, S. 2025. Carrying oversized loads may create “blind spots” in leafcutter ants. Insectes Sociaux, 1-13.

Leafcutter ants collect leaves, flowers, and other plant material as a substrate to grow a specialized fungus that serves as their food source

Some leafcutter ant species can carry loads that are up to 8 times their body weight, but oversized loads can slow them down and create “blind spots.”

Credit

Steven Paton

First author of the publication and STRI intern Katherine Porras, observing video recordings of leafcutter ants in Parque Metropolitano, Panama City.

Credit

Katherine Porras

About the Smithsonian Tropical Research Institute

Headquartered in Panama City, Panama, STRI is a unit of the Smithsonian Institution. Our mission is to understand tropical biodiversity and its importance to human welfare, to train students to conduct research in the tropics and to promote conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Watch our video, and visit our website, Facebook, X and Instagram for updates.

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Journal

Insectes Sociaux

Article Title

Carrying oversized loads may create “blind spots” in leafcutter ants

 

Study: Tariffs have potential to reshape US beer market

University of Illinois at Urbana-Champaign, News Bureau

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CHAMPAIGN, Ill. — The ripple effects of increased tariffs under President Trump could extend to the $117 billion U.S. beer market, according to new research from a University of Illinois Urbana-Champaign agricultural economist who studies food supply chains.

While tariffs could stimulate increased domestic beer production, any gains in domestic market share would most likely be concentrated among a few multinational firms rather than the nearly 10,000 small, independently owned craft breweries, said Aaron Staples, a professor of agribusiness management.

“The beer industry is commonly divided into three segments: craft beer brewed by small businesses, domestic noncraft beer owned by multinational firms, and imported beer,” he said. “Tariffs can raise domestic beer production costs and the price of imported beer. When these costs are passed down to the consumer, it can influence beer purchasing behaviors. We wanted to gauge how consumers would respond to tariff-driven price increases and predict how it would impact each market segment.”

The paper, published in the journal Food Policy and co-written by Michael McCullough of California Polytechnic State University, examined the potential effects of tariffs on beer demand, market shares and consumer welfare.

Using experimental data from more than 700 U.S. beer drinkers, the researchers arrived at three key findings, each with policy implications and industry relevance:

• Tariffs could stimulate domestic beer production, but the gains in domestic market share would likely be primarily confined to multinational firms rather than local entrepreneurs.
• Small businesses could lose market share if their limited economies of scale and reduced supply chain flexibility lead to higher proportional price increases compared to well-established national brands.
• The net reduction in consumer welfare via higher beer prices ranged from $53.1 million to $306.4 million, where the estimate depends on the tariff structure and the resulting price increases.

While tariffs are not directly imposed on consumers, they can still have a discernible impact on U.S. beer drinkers for several reasons, Staples said. For example, the U.S. market share for imported beer has increased from 14% to 24% since 2013. Mexico alone accounts for approximately 83% of U.S. beer imports, meaning roughly one in five beers consumed in the United States comes from Mexico.

“Most Mexican beer was exempt from initial tariffs under the United States-Mexico-Canada Agreement, but there is now a 50% tariff on the aluminum content of imported beer,” he said. “If this cost is passed down the supply chain, consumers could pay higher retail prices for their favorite Mexican lager. Small international brands may also consider discontinuing distribution to the U.S. if tariffs render the decision unprofitable, thereby reducing product variety.”

In that scenario, the market share for imports could fall, and any gains to domestic beer production from tariffs “would primarily flow to the multinational companies that purchase ads during football games, not the small craft breweries that have become cornerstones of local economies,” Staples said.

“In fact, we’re already starting to see a shift in business strategies among some of the multinational firms,” he said. “From investments in new production plants to marketing beer as ‘American made’ rather than ‘domestic,’ multinational firms are playing up the nationalistic aspect of their beer.”

But the impact of tariffs is not isolated to imported beer. Tariffs can increase domestic beer production costs given the reliance on international trade for agricultural and nonagricultural inputs, including malt, hops, steel and aluminum.

When these inputs are taxed, the cost of domestic beer production increases.

“Businesses may try to absorb these at first, but there comes a point where some of these increased costs will eventually be passed along to consumers,” Staples said.

This is especially worrisome for smaller craft brewers, which operate on tighter profit margins and have limited supply chain flexibility, Staples said.

“The multinationals will likely have a better buffer to weather these cost increases brought about by tariffs,” he said. “They have economies of scale, hedge against market disruptions and can negotiate with suppliers due to their strategic positioning. The average craft brewer can’t do this, making them more susceptible to market disruptions.”

If craft brewers start to falter, it could have broader implications for local economies, Staples said.

“The impact of the tariffs might not be immediate. The effects could be delayed until the inventory on hand dries up or brewers decide they can no longer afford to absorb these added costs,” he said. “But once beer prices go up, we don’t typically see them come back down.”

Tariffs remain a central policy topic, and the legality of certain tariffs has recently been called into question, Staples noted.

“It’s a very fluid and uncertain situation overall, one that ultimately points to higher consumer prices and a shifting market landscape,” he said.

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Journal

Food Policy

DOI

10.1016/j.foodpol.2025.102947 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Tariffs and U.S. beer demand: How protectionist policies could impact market shares and consumer welfare

Article Publication Date

6-Oct-2025