Lost medieval manuscripts inferred by family tree

PNAS Nexus

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Chanson d'Aspremont (a version of the Legend of Roland). Shelfmark: Lansdowne 782.

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Credit: From the British Library archive. E50003-09

For every King Arthur or Roland, whose adventures readers can still enjoy today, another hero of ancient literature may have been lost forever. Before the printing press, texts were copied manually. This process introduced errors and innovations. Like mutations in the replication of DNA, these manuscript changes can be used to create evolutionary trees that philologists call stemmata. Since these trees are based on the extant copies, they do not reflect the full evolutionary history of texts and cannot account for the ones that are completely lost. Jean-Baptiste Camps and colleagues use a complexity science approach to estimate the amount of lost literature among chivalric narratives, beginning in the 12th century. Agent-based simulations suggest that up to 60% of texts and more than 95% of manuscripts may have been lost. The model reveals that the first few years after a text’s creation are key: If few copies are made, the work is at high risk of extinction. The model also suggests that for most texts, no existing copies capture the original state of the work; all surviving texts are likely to be from a subsidiary branch of a given work’s family tree. The oldest version of the Song of Roland is probably unknowable, for example. Seemingly random accidents or major historical contingencies, such as the Black Death, also likely led to the extinctions of texts. According to the authors, cultural heritage is fragile, and the model helps understand how randomness, historical contingencies, and human choices shaped the literature we inherit today.

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Journal

PNAS Nexus

Article Title

On the transmission of texts: Written cultures as complex systems

Article Publication Date

7-Jul-2026

Birds may fly far, but their parasites do not

Estonian Research Council

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A sampled Greenlandic Arctic char

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Credit: Estonian University of Life Sciences

A new study published in the Journal of Helminthology by researchers from the Estonian University of Life Sciences and the Swedish University of Agricultural Sciences together with collaborators from Greenland and the Faroe Islands, has revealed surprisingly limited dispersal of Diplostomum parasites across North Atlantic islands. The findings challenge the common assumption that migratory birds readily transport parasites over large geographic distances.

Diplostomum is a genus of trematodes (parasitic flatworms) ubiquitous in freshwater ecosystems. They are characterised by a complex life cycle involving aquatic snails, fish, and fish-eating birds as their definitive host. Because these birds typically undertake annual migrations from southern wintering areas in the south to Arctic breeding grounds, they serve as an ideal model system for studying long-distance dispersal and biological connectivity. To test the role of the avian host as a potential parasite dispersal vector, the international research team investigated the diversity and distribution of Diplostomum parasites infecting freshwater salmonids in Greenland and the Faroe Islands. They utilized modern DNA metabarcoding, a next-generation sequencing, method that allows the simultaneous characterisation of complex communities using short DNA fragments.

The researchers found striking differences between the North-Atlantic island systems. In Greenland, infections were common in Arctic char and Atlantic salmon and the genetic analyses revealed four parasite lineages, including a potentially undescribed new species. In contrast, no Diplostomum infections were detected in brown trout or Atlantic salmon sampled from sixteen streams across the Faroe Islands.

The findings suggest that migratory birds are not always effective vectors of parasite dispersal, and other factors may limit parasite spread across ecosystems. Consequently, parasite communities in Greenland were more closely related to those found in North America than to those reported from Iceland or northern Europe. Despite being potentially connected by the migration of the avian definitive hosts, the results indicate a limited exchange of parasites across the North Atlantic.

“Given the extensive movements of migratory birds across the North Atlantic, we initially expected much greater overlap in parasite communities among North-Atlantic islands,” said the first author, Alfonso Díaz-Suarez, a postdoctoral researcher at the Estonian University of Life Sciences, “Instead, we found striking differences between regions, indicating that Diplostomum parasites have a more limited distribution despite the presence of highly mobile hosts.”

The researchers suggest that this limited distribution may result from a short transmission season, with parasite transmission occurring only during the breeding season of the avian definitive host in the Arctic and not in the southern wintering areas. This temporal limitation of transmission together with specific migration routes and host distribution, may substantially reduce opportunities for successful parasite colonization between island systems.

“Many people assume that migratory birds freely transport parasites across vast geographic distances,” added Professor Anti Vasemägi. “Our findings suggest that successful parasite dispersal is much more restricted and depends on a combination of host movements, environmental conditions, and the complex life cycles of the parasites themselves.”

One of the most intriguing discoveries was the identification of a potentially new parasite species in Greenland. The finding suggests that North Atlantic and Arctic ecosystems may harbour unique parasite biodiversity that has remained undocumented.

Such hidden diversity may provide valuable insights into evolutionary processes, host–parasite interactions, and the historical colonization of northern freshwater ecosystems. The study also demonstrates the power of modern DNA-based methods for uncovering biodiversity that would be difficult to detect using traditional approaches alone, which can be an essential tool to explore the diversity of a changing ecosystem.

Beyond advancing the understanding of parasite ecology, the findings highlight a broader lesson about biological connectivity. While migratory birds are often viewed as powerful agents of dispersal, complex life cycles and ecological constraints can strongly limit the movement of associated organisms.

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Journal

Journal of Helminthology

DOI

10.1017/S0022149X26101631 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Not-so-frequent flyers? Restricted avian dispersal of Diplostomum parasites across North Atlantic islands

 

Sight-fishing for eye parasites

 

A typical Faroese stream near a sheep farm

 

Using eDNA sampling to identify additional species

Credit

Estonian University of Life Sciences

Parasites deliver long-chain omega-3 fatty acids to aquatic systems

PNAS Nexus

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Schematic overview of the hypothesized reciprocal EPA flow between forest and stream ecosystems, taxon-specific EPA contents, and EPA intake of
fish.

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Credit: Ayano Medo and Takuya Sato

Wormlike parasites cause crickets to jump into streams, where the fatty insects nourish endangered fish. Ayano Medo and Takuya Sato sought to characterize the flow of eicosapentaenoic acid (EPA)—a nutritious long-chain omega-3 fatty acid—through aquatic and terrestrial ecosystems. EPA in human diets often comes from fish. Aquatic algae synthesize significant amounts of EPA, and it was thought that fish acquired most of their EPA from aquatic invertebrates that eat the algae. However, from the middle of August to late October, nematomorph parasites induce terrestrial crickets to jump into water, where the parasite completes its life cycle and where salmonid fish, such as an endangered species of charr (Salvelinus leucomaenis japonicus), gorge themselves on these substantial terrestrial insects. Previous work shows infected crickets and katydids account for 60% of the annual energy intake of an endangered charr population in a temperate forested stream in Japan. The authors measured the EPA levels in camel crickets, which are known to scavenge weak and dead aquatic insects and found that camel crickets have around 4–17 times more EPA than known aquatic invertebrates, and nematomorph infections did not reduce EPA. According to the authors, as nematomorph parasites are common globally, parasite-mediated movements of land insects to water may be a common mechanism by which EPA flows from terrestrial to aquatic ecosystems.

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Journal

PNAS Nexus

Article Title

Nematomorph parasites potentially drive nutritional flow from terrestrial to aquatic ecosystems

Article Publication Date

7-Jul-2026

 

Birds’ efficient red blood cells convert metabolic “waste” into fuel for rapid recovery

Society for Experimental Biology

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Fluorescence microscopy image of chicken red blood cells. Nuclei are shown in blue and mitochondria in orange.

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Credit: Yi Yang, Hickey Lab, The University of Auckland

New research finds that birds can use lactate, often thought of as a metabolic waste product, as a cellular fuel that aids in rapid recovery from a harmful state that impairs oxygen delivery. Haemoglobin, the protein that carries oxygen to our tissues, naturally converts to methaemoglobin, which limits the blood’s oxygen-carrying capacity. This research shows how bird red blood cells (RBCs) can use lactate to rapidly resurrect blood function, and they can do this better than mammals because they contain mitochondria — the “powerhouses of the cell” — something that mature mammalian RBCs do not possess.

It is widely thought that mammals have lost mitochondria and nuclei from RBCs to increase oxygen delivery. However, birds and other non-mammalian vertebrates retain these organelles. “This raises an important question: what benefits or costs does the loss of mitochondria incur?” says Yi Yang, a PhD student at the University of Auckland, New Zealand.

Birds have incredibly high energetic needs compared to mammals, and their anatomy and physiology have evolved to use oxygen more efficiently. Miss Yang and her team wanted to investigate the role of the mitochondria in how bird RBCs respond to oxidative stress that damages haemoglobin and explore fuels that could be used to fix damaged RBCs. Of several possible metabolites, lactate appeared to help convert methaemoglobin back to haemoglobin.

Classically, lactate has been thought to be a waste product of anaerobic metabolism during high-intensity exercise, but it is increasingly being recognised as an important signalling molecule. Lactate itself can act as an antioxidant, but it also contains energy and can generate NADH, a molecule used in many pathways, including recharging antioxidant systems and restoring haemoglobin function.

This research, presented at the Society for Experimental Biology conference in Florence, Italy, demonstrates how bird RBCs harness lactate to maintain healthy cellular metabolism.

“Our study shows that lactate helps protect avian RBCs’ haemoglobin by harnessing mitochondrial metabolism,” says Miss Yang. “As mature mammalian RBCs lack mitochondria, they are unable to fully utilise this pathway.”

Lactate can be used by lactate dehydrogenase (LDH) to form NADH and pyruvate. NADH can be used to convert harmful methaemoglobin back into useful haemoglobin, but the pyruvate must be removed or the reaction stops. “Birds, however, can oxidise and remove the resulting pyruvate, which helps sustain NADH production and maintain haemoglobin in its functional state,” says Miss Yang.

To assess differences in lactate management of bird and mammalian RBCs, Miss Yang and her team measured LDH activities and types in chickens (Gallus gallus domesticus) and rats (Rattus norvegicus) and measured how much oxygen RBCs consumed inside a controlled chamber, to which they added different metabolic fuels such as lactate and glucose. The team then subjected the RBCs to oxidant challenges that promote the conversion of haemoglobin to methaemoglobin.

They found that lactate enabled chicken RBCs to convert the methaemoglobin back to haemoglobin three times faster than the rat RBCs could. Lactate addition increased apparent oxygen consumption in both chicken and rat RBCs, but the response was substantially greater in chicken RBCs. In part, this was because reformation of functional haemoglobin-bound oxygen, and mitochondria began to oxidise pyruvate.

In addition, chicken RBCs express a form of LDH typically expressed in the heart, while rats express a form associated with skeletal muscle. The heart-type LDH works better at turning lactate to pyruvate.

The most surprising finding of this research is that the mitochondria in bird RBCs support the removal of methaemoglobin. “At first glance, retaining mitochondria might seem risky for bird RBCs because mitochondria result in larger cells, which can impact oxygen delivery,” says Miss Yang. “However, our findings show that mitochondria aid methaemoglobin reduction by consuming pyruvate.”

While work in the 1970s hinted at lactate use by RBCs containing mitochondria, this is the first time that the mitochondrial mechanisms underlying these processes in bird RBCs have been revealed to protect oxygen supplies.

This research opens up the question of which other cells, tissues and animals are also able to use lactate in this way. Miss Yang and her team are now interested in further investigating the roles of lactate and other metabolic products in other vertebrates.

 

Mount Sinai receives $7.2 million NIH grant to advance precision medicine for peanut allergy treatment

New multidisciplinary research center will identify biomarkers and biological pathways that predict response to peanut allergy treatments

The Mount Sinai Hospital / Mount Sinai School of Medicine

 at Mount Sinai have been awarded a five-year, $7.2 million grant from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), to establish a new Asthma and Allergic Diseases Cooperative Research Center focused on advancing personalized treatment strategies for peanut allergy.

The study, known as Immunologic Trajectories of Peanut Desensitization or INROADS, will investigate the biological mechanisms that drive peanut allergy desensitization and identify biomarkers that can help predict which patients are most likely to benefit from treatment. The initiative brings together experts in allergy, immunology, omics, artificial intelligence, computational biology, and clinical research from across Mount Sinai to advance precision medicine approaches for food allergy care.

Peanut allergy affects nearly 2 percent of adults and up to 5 percent of children in some regions of the United States. Its prevalence has tripled in recent decades, making it one of the most common and potentially life-threatening food allergies. Although recently approved therapies—including peanut oral immunotherapy and the allergy medication omalizumab—have improved treatment options, clinicians currently have no reliable way to predict treatment response or understand why therapies are effective for some patients but not others.

“Mount Sinai has played a leading role in developing and advancing therapies that have transformed care for patients with peanut allergy,” said Supinda Bunyavanich, MD, MPH, MPhil, Contact Principal Investigator of INROADS and Deputy Director of the Elliot and Roslyn Jaffe Food Allergy Institute at Mount Sinai Kravis Children’s Hospital. “This new center allows us to take the next critical step toward precision medicine by identifying the immune and molecular pathways that determine treatment success. Our goal is to help ensure that every patient receives the therapy most likely to benefit them.”

Dr. Bunyavanich is also the Mount Sinai Professor in Allergy and Systems Biology and a Professor of Pediatrics, and Genetics and Genomic Sciences, at the Icahn School of Medicine at Mount Sinai.

The INROADS center builds on decades of pioneering peanut allergy research at Mount Sinai, including studies that contributed to Food and Drug Administration approvals of peanut oral immunotherapy and omalizumab. Investigators recently demonstrated that, through careful characterization of peanut allergy sensitivity, many patients can be safely and effectively desensitized using measured amounts of store-bought peanut products. These findings may help expand access to treatment and challenge longstanding assumptions about peanut allergy management.

“Families living with peanut allergy face constant uncertainty and vigilance,” said Scott H. Sicherer, MD, Multiple Principal Investigator of INROADS, Director of the Jaffe Food Allergy Institute, and Chief, Serena and John Liew Division of Pediatric Allergy and Immunology at the Icahn School of Medicine at Mount Sinai. “The discoveries generated through this center have the potential to fundamentally improve how we deliver desensitization therapies, making them more personalized, more effective, and ultimately more accessible for patients and families.”

The center includes two major research projects:

• MICRO-TRACK, which will use advanced immune profiling technologies, allergen-specific T cell studies, and laboratory models to identify biological markers that predict treatment response and reveal mechanisms of immune regulation during desensitization.
• SPADE, which will apply transcriptomics and machine learning approaches to uncover molecular signatures associated with successful desensitization and develop predictive tools that may help guide clinical decision-making.

Supporting these projects will be three integrated cores:

• PATHWAYS Clinical Core, which will provide clinical data and biological samples from patients undergoing oral food challenge testing before and after desensitization therapies
• Administrative Core, which will coordinate scientific activities, center operations, and collaborations across the national Asthma and Allergic Diseases Cooperative Research Center network
• Data Stewardship Core, which will oversee biospecimen management, data integration, and sharing of research resources with the broader scientific community

By combining detailed clinical information with comprehensive immune and molecular analyses, investigators aim to create one of the most robust datasets ever assembled for peanut allergy desensitization research. These data will be made publicly available to accelerate discovery and collaboration across the field.

“Our integrated approach brings together clinical expertise, cutting-edge immunology, omics, artificial intelligence, and computational science to answer some of the most important unanswered questions in food allergy research,” said Dr. Sicherer. “The insights gained from INROADS may not only improve outcomes for peanut allergy but also inform the treatment of other food allergies and allergic diseases.”

Faculty participating in the center also include Erik Wambre, PhD; Julie Wang, MD; Pei Wang, PhD; Kristin Beaumont, PhD; and Seung-Hee Kim-Schulze, PhD, representing the Departments of Pediatrics, Genetics and Genomic Sciences, Immunology and Immunotherapy, and related research programs across the Icahn School of Medicine at Mount Sinai.

The INROADS center is funded by NI AID through the Asthma and Allergic Diseases Cooperative Research Centers program.

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About the Mount Sinai Health System 

Mount Sinai Health System is one of the largest academic medical systems in the New York metro area, with approximately 48,000 employees working across seven hospitals, more than 400 outpatient practices, more than 600 research and clinical labs, a school of nursing, and leading schools of medicine and graduate education. Mount Sinai advances health for all people, everywhere, by taking on the most complex health care challenges of our time—discovering and applying new scientific learning and knowledge; developing safer, more effective treatments; educating the next generation of medical leaders and innovators; and supporting local communities by delivering high-quality care to all who need it. 

Through the integration of its hospitals, labs, and schools, Mount Sinai offers comprehensive health care from conception through geriatrics, leveraging innovative approaches such as artificial intelligence and informatics while keeping patients’ medical and emotional needs at the center of all treatment. The Health System includes more than 9,000 primary and specialty care physicians and 10 free-standing joint-venture centers throughout the five boroughs of New York City, Westchester, Long Island, and Florida. Hospitals within the System are consistently ranked by Newsweek’s® “The World’s Best Smart Hospitals,” “Best in State Hospitals,” “World’s Best Hospitals,” and  “Best Specialty Hospitals” and by U.S. News & World Report's® “Best Hospitals” and “Best Children’s Hospitals.” The Mount Sinai Hospital is on the U.S. News & World Report® “Best Hospitals” Honor Roll for 2025-2026.  

For more information, visit https://www.mountsinai.org or find Mount Sinai on Facebook, Instagram, LinkedIn, X, and YouTube. To listen to news and stories from Mount Sinai, visit the Mount Sinai Podcast Network.

High levels of forever chemicals found on wastewater filters

A significant buildup of “forever chemical” concentrations on reverse osmosis filters used in desalination and advanced wastewater treatment highlights the need for proper handling, disposal and recycling.

Texas A&M University

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A reverse osmosis facility featuring hundreds of filters used in water treatment.

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Credit: Dr. Shankar Chellam

As cities across the nation and the globe increasingly turn to advanced water purification systems to expand their drinking water supplies, researchers at Texas A&M University have identified a critical environmental safety consideration. A new study from the Department of Civil and Environmental Engineering shows that per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” accumulate significantly on the purification filters used in advanced treatment to recycle wastewater into drinking water.

This breakthrough research examines a real-world potable reuse facility, where municipal wastewater is currently treated to very high standards to produce safe drinking water. Although the technology effectively removes contaminants, the study shows for the first time that microscopic trapping of harmful chemicals causes significant accumulation on the filters over their operational lifespan.

These findings carry implications for public health and environmental policy. When water utilities replace thousands of worn-out filtration membranes, the accumulated PFAS could pose risks to workers handling the equipment or leach into local groundwater if the components are discarded improperly. By detailing exactly how and where these persistent chemicals accumulate, the research provides engineers with the foundational data needed to develop safer disposal protocols and advanced cleaning techniques.

Civil and environmental engineering professor Dr. Shankar Chellam, his post-doctoral fellow Dr. Onkar Ekande, his former Ph.D. student Dr. Bilal Abada, and Brent Alspach, director of applied research at Arcadis, were co-authors of the study, published in the Journal of Membrane Science.

The research team analyzed several commercial reverse osmosis filters — coiled, sheet-like polymer membranes — that had been operating for four consecutive years at a full-scale potable reuse facility. 

“Reverse osmosis is excellent at removing PFAS, just like it’s excellent at removing salts,” said Chellam. “It’s literally a desalination technology, and it is good for removing a lot of contaminants, but it’s expensive.”

Reverse osmosis works by forcing water through a dense, highly selective polymer membrane under high pressure, leaving salts, minerals and contaminants behind. Because wastewater contains much higher levels of PFAS than typical freshwater sources like lakes or rivers, these filters face an intense barrage of chemical pollutants over years of continuous service in a potable reuse plant.

This research addresses a crucial gap by analyzing the concentrations of these chemicals on the filters themselves. The team discovered that long-chain PFAS compounds often bind strongly to organic and biological fouling layers — slimes or biofilms composed of proteins, sugars and microorganisms — that naturally form on filter surfaces over time.

“There could be a correlation between the bio-organic fouling and PFAS accumulation on the filter surfaces,” said Abada. “In all but the very last filtration stage, we found organic fouling.”

The researchers discovered that long-chain, water-repelling PFAS variants accounted for two-thirds of the trapped chemical mass in the initial stages of membranes. Additionally, chemical precursors — compounds that degrade over time into more stable forms of PFAS — accounted for another 14% of the accumulation. In contrast, the final stage of the filtration system, which was dominated by chalky mineral scales rather than organic slime, retained almost no PFAS.

“PFAS is toxic at very low concentrations, and they have been reported in numerous drinking water sources and wastewater,” said Chellam. “The removal technologies currently in use, such as reverse osmosis, take a water stream that is relatively dilute in PFAS and concentrate the toxic chemicals to much higher levels on the filters.”

The conclusions drawn from this study add critical data on a widely concerning pollutant and support policymaking and regulatory oversight. Future research on PFAS mitigation technologies can also benefit from these results in terms of membrane life cycle analysis.

“The problem of membrane use, cleaning and disposal will only become bigger and bigger,” said Abada. “Even if we become more efficient and make the membranes last longer, we still have to figure out how to safely handle and dispose of them once they reach their end of life.”

As water-stressed communities continue to adopt advanced recycling technologies, these insights help ensure they can do so with a better understanding of the impact of PFAS accumulation on membrane lifecycles.

By Justin Agan, Zachry Department of Civil and Environmental Engineering, Texas A&M University

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DOI

10.1016/j.memsci.2026.125425 

Article Title

Accumulation of per- and polyfluoroalkyl substances and their precursors in fouling layers on end-of-life reverse osmosis membranes in a full-scale potable reuse facility