Friday, August 21, 2026

Researchers identify the immune cells that keep a deadly fungus in check

A Virginia Tech study finds that control of Cryptococcus neoformans depends not on a single immune cell type, but on several working together — a discovery that could reshape how doctors think about preventing life-threatening fungal infections.

Virginia Tech

Most people carry the fungus Cryptococcus neoformans in their lungs for life and never know it, held in check by the immune system. New research from the Virginia-Maryland College of Veterinary Medicine at Virginia Tech identifies which immune cells do that work — and finds that no single cell type is responsible.

The study, published in the journal mBio, focused on CD4 T cells, the immune system's coordinators. Researchers had long assumed one dominant cell type controlled the infection. Instead, they found several distinct CD4 T-cell populations, each contributing in its own way.

"Everybody assumed we had the queen that was going to be the single most powerful player," said senior author Kirsten Nielsen, professor of microbiology and immunology at the college's Center for One Health Research. "But it turns out it's not just one queen. Imagine playing chess with five queens."

The finding matters because Cyptococcus turns deadly when the immune system falters. In people undergoing chemotherapy, recovering from organ transplants, living with HIV, or taking immune-suppressing drugs, the dormant fungus can reactivate, spread to the brain, and cause meningitis. It kills more than 150,000 people worldwide each year and is the second-leading cause of death among people living with HIV, according to the CDC and World Health Organization.

Doctors currently cannot predict or prevent that reactivation, in part because it was unclear which immune cells were containing the fungus in the first place. Because no single cell type is responsible, the results suggest that any future preventive treatment will need to protect a coordinated network of immune cells rather than target one.

The work is the latest advance in a research program Nielsen has built over more than a decade, tracing to her insight that the outcome of infection is decided in the lungs — not the brain, where symptoms appear. Reproducing the quiet, lifelong lung infection in mouse models took years before her lab, first at the University of Minnesota and now at Virginia Tech, could begin asking which immune cells mattered.

The fungus is also a veterinary concern, infecting cats, dogs, and pet birds. Because animals mount similar immune responses, the findings are expected to inform both human and animal medicine — a connection central to the veterinary college's One Health mission.

"We've added another piece to the puzzle," Nielsen said. "The picture is starting to resolve, but we're still a long way from completing it." Her team has not yet determined how these T cells communicate with the front-line cells they direct — the next step in the work.

The study, "Paradoxical Th1 activation and CTLA-4 regulation is beneficial during latent cryptococcosis," was supported by the National Institutes of Health, with collaborators at Harvard University and the University of Illinois.

Journal

mBio

DOI

10.1128/mbio.01528-26

Article Title

Paradoxical Th1 activation and CTLA-4 regulation is beneficial during latent cryptococcosis

Mountain hayfields can filter nutrients and support clean water

Colorado State University

Irrigated mountain hayfields can act as large filtration systems that reduce sediment, phosphorus and other contaminants from runoff, sometimes improving the quality of water flowing back into the environment, Colorado State University research has found.

The findings result from a producer-driven, three-year study by CSU’s Agricultural Water Quality Program in the Yampa, Gunnison and Colorado River basins.

The examination of agricultural impacts on water quality found consistently low nutrient concentrations in runoff from Colorado hayfields – lower than levels warranting concern and sometimes lower than when the water was applied to fields.

"These irrigated ag lands in the mountains are essentially large grass filter strips,” said Erik Wardle, director of the Agricultural Water Quality Program, who conducted the research. “Their impacts are very low, and in some cases, they even have the potential to clean the water, depending on management and localized conditions.”

Excess nutrients, such as nitrogen and phosphorus, can cause algal blooms, which are unhealthy for people and animals, especially aquatic life. These nutrients are found in fertilizer, but they’re also found in nature, wastewater and urban stormwater.

Planting perennial grass strips along the edges of fields where row crops such as corn and soybeans are grown is a best practice to prevent fertilizer and sediment from running off into water supplies. The study found that Colorado’s mountain meadows, which are large perennial grass fields, serve this purpose when nutrients required for plant growth are managed judiciously.

Data from the study benefits producers and state agencies by providing baseline measurements and showing that voluntary adoption of best management practices can effectively mitigate the impacts of agricultural nutrient use in mountain meadow hay systems.

Colorado’s nutrient control Regulation 85 restricts nutrients to protect water quality. The Water Quality Control Division monitors wastewater treatment plants and some industrial sources but currently does not regulate most agricultural systems. However, agriculture is continually evaluated, and the division has the authority to recommend regulations if deemed necessary. For now, agricultural producers are tasked with using best management practices and demonstrating sufficient progress in water quality protection.

The Colorado Ag Water Alliance, a group of producers and partner organizations dedicated to preserving water resources, requested the study to understand whether hay production and grazing were contributing nutrients to mountain surface water. The study was funded by the Colorado Department of Public Health and Environment and the Environmental Protection Agency. Several producers, one in each basin, volunteered their property for water quality monitoring. CSU’s Agricultural Water Quality Program tested irrigation water before and after it was applied to fields.

Greg Peterson, executive director of Colorado Ag Water Alliance, said this was the first study of its kind to examine mountain meadow hay operations and water quality.

"A lot of us in the agricultural community were a bit worried about experimenting with these kinds of practices, because what if we see something wrong? Are we going to get in trouble?” Peterson said. "But it really gave participating producers the freedom to experiment and identify things that were a benefit to them and water quality.”

Mountain meadow hay has a short growing season, and producers in these systems typically don’t use much fertilizer, which is expensive. Participating in the project allowed them to test different management practices to optimize fertilizer use and water quality.

"One of the sites was just open space, and there wasn't much difference from the local ranch and that open space site,” Peterson added.

Colorado Farm Bureau President Carlyle Currier, who is also a board member of the Colorado Ag Water Alliance, said he was pleased with the results of the study. Currier chose to evaluate the area of his ranch he was concerned had the most potential for contamination. Results validated that the water leaving his field was generally better quality than the water used to irrigate it.

"Farmers and ranchers are the original environmentalists,” Currier said. “We use natural resources to produce our crops and livestock, and they're very dependent on having a good clean environment. We'd destroy our livelihood if we destroy the environment. My family's been in operation on the same land for well over 100 years. To know that we are protecting the environment and doing things right is very good for us.”

Hay production and forage pastures feed livestock, Colorado’s top agricultural commodity. Wardle said ranches are important to mountain communities and the economy.

“Many of these ranches have been there 100 years or more, so they're very much a part of the ecosystem in the mountains,” he said.

The mountain meadow hay study has led to a new Colorado Water Plan project in the Yampa River Basin. The new project will demonstrate and evaluate best management practices in mountain meadow hay systems, building on this producer-driven research.

The report, "Nutrient Management on Irrigated Pastures," is available upon request.

Molecular 'bypasses' improve grass plants’s synthesis of lignin and starch, laying the early groundwork for evolutionary success

University of Wisconsin-Madison

Joinvillea plant — image:
Scientists examined the genome of Joinvillea, a close relative of grasses, to gain insight into how grasses evolved.
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Credit: Sarah Friedrich / UW–Madison

One hundred million years ago, long before human intervention, ancestors of grasses, like wheat, rice and maize generated “bypasses” of chemical pathways that are used to create two critical compounds: lignin and starch. These more efficient pathways could explain why grass plants are so successful in nature and agriculture, according to a new paper publishing in Science on Aug. 20 by researchers from the University of Wisconsin–Madison and their collaborators.

Like a beltway that creates a more flexible traffic flow in a city, these metabolic bypasses led to efficient and robust synthesis of both lignin and starch, chemical compounds that are critical for plants.

Grasses and cereal grains make up the majority of global human caloric intake. However, it remains a mystery how these grasses became dominant and successful in both nature and later in agriculture. The lab of Hiroshi Maeda, a professor of botany at UW–Madison, teamed up with researchers from around the world to address this question.

The team was particularly interested in the metabolism of grasses, focusing on genes that are needed to make starch and lignin. Grasses are rich in starch, a complex carbohydrate that acts as the plant’s energy storage, and their rapid growth requires the efficient production of lignin, a major component of plant biomass.

Just as scientists use the chimpanzee’s genome as a comparison tool to study how humans evolved, Maeda’s group and their collaborators, James Leebens-Mack from University of Georgia, turned to the closest relatives of grasses, such as Joinvillea ascendens.

This long-leafed plant is found in wet forests of the South Pacific islands and grows much more slowly than many grasses.

Only two out of over 100 seeds obtained from the National Tropical Botanical Garden in Hawaii germinated initially. It took another two years for these plants to grow large enough to be harvested for genomic sequencing. Then, they were finally able to sequence the genomes of Joinvillea, along with three related species.

Comparing thousands of genes found in these genomes, they revealed that Joinvillea has only one pathway to create starch. All grasses, though, have two.

This means that an additional starch synthesis pathway, or a bypass route, emerged at the common ancestor of all grasses and now allows grasses to produce double the amount of energy than Joinvillea and other non-grass plants.

In the natural world, a seed with more energy packed inside can germinate, sprout out of the ground, and begin the process of photosynthesis sooner. That allows the plant to grow taller quickly, outcompeting surrounding slower growing plants.

“That likely gave a competitive advantage to grasses to grow in open habitat, where a lot of plants would love to grow because of all the sun,” Maeda says. ”That's one potential reason why grasses ended up maintaining this highly efficient starch pathway. That same metabolic trait was also very beneficial to agriculture.”

The researchers, including Maeda’s postdoctoral researcher, Yuri Takeda-Kimura, were also interested in how grasses and Joinvillea produced lignin, a chemical compound that gives strong structural support to plants. Plants with high lignin content, like woody plants, tend to grow slowly. Grasses, however, are an exception; they can grow rapidly despite having relatively high lignin contents.

Tracing back the history of lignin synthesis pathways, the team found that both grasses and Joinvillea had two pathways for lignin synthesis. This time, Joinvillea had two.

“It turned out, this unique feature of grasses, capable of synthesizing lignin by two routes, evolved even before grasses existed”, Maeda says.

Knowing when this critical change happened, the team further discovered how the dual lignin pathways were generated.

“We found two mutations in their DNA that are critical and sufficient to create this new bypass pathway,” Maeda says. “So, that means, we can actually introduce similar mutations in other plants to create this second lignin pathway.”

Maeda says that understanding what makes grasses unique opens doors for future improvements to cereal and bioenergy crops and other plants, whether it be augmented energy stores through additional starch synthesis pathways or improved structure strength and resilience through increased production of lignin and other related compounds.

Maeda and his collaborators are using this basic science knowledge for potential applications in plant biotechnology to improve sustainable production of beneficial nutrients and other useful chemicals in agricultural and bioenergy crops.

This work was supported by the U.S. National Science Foundation (NSF) Plant Genome Research Program (IOS-1836824) and the U.S. Department of Agriculture (NIFA-2024-67013-42518). Funding was also provided by the Oversea research fellow of the Japan Society for the Promotion of Science (JSPS), United Kingdom Research and Innovation-Biotechnology and Biological Sciences Research Council, Norwich Research Park Doctoral Training Partnership (grant no. BB/M011216/1), Institute Strategic Programme (grant no.BB/P012574/1 and BBS/E/J/000PR9795), Gatsby Charitable Foundation, United States Department of Agriculture-Agricultural Research Service CRIS #5062-21220-025-000D, the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337; proposal:10.46936/10.25585/60001405), the Office of Science of the U.S. Department of Energy, the U.S. National Science Foundation (NSF) EPSCoR (OIA-1920858), Rules of Life (DEB-2001190) programs, and U.S. Army Corp of Engineers (USACE) Sustainable Rivers (W9126G-23-2-0018).

Journal

Science

DOI

10.1126/science.adv0443

Method of Research

Observational study

Article Title

Genomes of Poaceae sisters reveal key metabolic innovations preceding the evolution of grasses

Article Publication Date

20-Aug-2026

Natural restoration is key to reviving threatened tropical rainforests

University of Queensland

As nations race to restore ecosystems and curb climate change, research has shown that letting nature do the work is a cost-effective and viable solution.

A study from The University of Queensland and the University of Newcastle found natural forest regeneration delivered substantial carbon and biodiversity benefits and could be up to 96 per cent cheaper than traditional tree-planting programs.

School of the Environment PhD candidate Jiaqi Li said the team researched how the costs and benefits of natural regeneration varied across the tropics and created an interactive global map to explore the opportunities for forest regions.

“Nature is a great gardener, sometimes we just need to get out of its way while providing a bit of support,” Ms Li said.

“For tree planting you need to purchase the seeds and hire workers or recruit volunteers to plant and manage them, which is costly.

“For natural regeneration people just need to check the land for invasive species and remove them, check there is adequate seed sources, put up protection from fire, grazing animals, and humans and then it is mostly self-sufficient.

“For many cases of natural regeneration, studies show that you can end up with a forest that could store more carbon and is more biodiverse than a planted forest.”

It’s been calculated that between 2000 and 2012, tropical forests were reduced globally by 2.3 million km², leading to the release of an estimated 0.86 gigatons of carbon annually and threatening the well-being of around 1.5 billion people dependent on forests.

“Forests are Earth’s life support systems and tropical forests are the most biodiverse amongst all the forest types, covering 18 per cent of the land and home to more than half of all land vertebrate species,” Ms Li said.

“They are also a giant carbon sink, so when deforestation happens we not only stop the forest up taking the carbon, but we also flip it and turn it into a carbon source.”

Ms Li said the study identified areas where natural regeneration provided high carbon benefits, high biodiversity benefits and low restoration costs and called them ‘holistic hotspots’.

These areas were mostly located Indonesia, Madagascar, Philippines, México, and Malaysia.

“The carbon benefits stand out most in Neotropic areas like the Amazon basin and in the Indomalaya Tropics like Borneo, Sumatra and Papua New Guinea,” Ms Li said.

“There are more biodiversity benefits in the Afrotropic including Madagascar.”

Senior author Dr Brooke Williams from the University of Newcastle said with the world pledging in 2022’s Kunming-Montreal Global Biodiversity Framework to restore 30 per cent of the Earth’s degraded land, natural restoration was more important than ever.

“The whole world is fighting to combat climate change and on top of that nations have goals to reverse the biodiversity crisis,” Dr Williams said.

“Restoring forests is expensive and the cost could mean some nations can’t meet their ambitious restoration goals.

“Our study gives a broad idea of the benefits and costs which could occur with natural regeneration.”

UQ Associate Professor Matthew Luskin who co-authored the study said the research was a huge leap forward in putting theories about forest restoration into practice.

“I've spent years in the forests around the tropics and seen rampant deforestation first-hand, but I've also seen huge opportunities for regrowth,” Dr Luskin said.

“This work will help countries and communities prioritise where and how to invest in restoration depending on their specific goals and resources to achieve the best outcomes.”

The research paper is published in Nature Ecology & Evolution.

Journal

Nature Ecology & Evolution

DOI

10.1038/s41559-026-03154-7

Method of Research

Data/statistical analysis

Article Publication Date

21-Aug-2026

Dark boreal forests of Canada absorb enough heat to cancel up to a fifth of their climate benefit, scientists warn

Canada's current carbon accounting scheme ignores how much sunlight a forest reflects, and the credits built on it may overstate what they deliver

United Nations University

Richmond Hill, Ontario, Canada (20 August 2026) – Dense evergreen plantations in Canada’s boreal forest absorb so much winter sunlight that the resulting surface warming can offset 6 to 20 percent of the climate benefit they are credited with. Canada’s current carbon accounting frameworks measure the carbon stored but largely omit the heat absorbed by these forests, according to a new Policy Brief from the United Nations University Institute for Water, Environment and Health (UNU-INWEH). The result is inflated mitigation estimates and public investment in forests that may not deliver the cooling they promise.

The Policy Brief “From Carbon Accounting to Net Cooling: Securing the Albedo-Carbon Double Win in Canada’s Boreal Forest” argues that Canada should judge reforestation by its net effect on temperature rather than by tonnes of carbon stored. “Canada has an opportunity here that few countries have,” said Professor Kaveh Madani, Director of UNU-INWEH. “It can be the first to verify forests on what they actually do to the climate, not on what they store on paper. That protects public money, and it protects the credibility of every credit this country issues. Climate leadership isn’t about planting more trees anymore. It’s about being able to show, decades from now, that the forest we planted is still cooling the ground it stands on.”

In snow-covered landscapes, the color of the land surface matters as much as what grows on it. Open snow reflects most of the sunlight that reaches it, but a dark spruce canopy absorbs it. A dense evergreen stand across a snowy landscape makes the ground measurably darker for months of the year, warming the surface even as the trees pull carbon from the air. Scientists call this reflectivity albedo, and most carbon accounting frameworks in use today do not subtract it.

The authors from UNU-INWEH, the University of Waterloo, and Polytechnique Montréal, find that offset frameworks counting stored carbon without deducting surface warming or adjusting for permanence risk systematically overstate reforestation’s true climate value. Evidence from the Taiga Plains shows that heat absorbed by dark spruce forests can offset 6-20 percent of their reported carbon gain. Afforestation and reforestation sit at the center of Canada’s climate commitments, which makes the gap expensive. The publication treats the exposure as fiscal as it is environmental. Public money may be flowing into forests that absorb more heat and carry elevated fire reversal risk. Without reform, the authors warn, Canada risks issuing low-integrity carbon credits. They call this a policy failure to measure net temperature impact, not a gap in the science.

“A forest can pass a carbon audit and still leave the surface warmer than it was. That’s the part nobody is measuring,” said Professor Pooneh Maghoul, Lead for Sustainable Infrastructure in Cold Regions at UNU-INWEH. “We’re not questioning whether trees help. We’re saying the ledger is incomplete, and in the North the missing entry is large enough to change the answer.”

Long-term modeling studies in northern Canada show that forest design decides the outcome. Mixed stands with 25 to 40 percent deciduous trees, planted at moderate densities of 600 to 1,400 trees per hectare, hold substantial carbon while reflecting more winter sunlight. They also burn less intensely. Dense evergreen mono-plantations do the reverse, intensifying competition for soil moisture and building the continuous fuel that drives high-severity fire in dry years. Wildfire, the Policy Brief argues, has become the primary constraint on carbon durability in a warming boreal system. In drought-prone country, a dense plantation is a fire liability rather than a climate asset.

“The question isn’t how many trees we plant. It’s what we plant, how densely, and whether the site can still hold water in thirty years,” said Professor Maghoul. “Get that wrong and you’ve spent public money on something that burns.”

The authors urge Canada to establish a Net Cooling Standard that deducts the Albedo Penalty and screens for wildfire permanence across all publicly supported reforestation. They also recommend confining restoration to hydrologically viable under-stocked land, and building a satellite-supported national platform to monitor soil moisture, fuel accumulation and surface reflectivity as conditions change.

Key Findings at a Glance

Heat absorbed by dark spruce forests can offset 6 to 20 percent of their reported carbon gains, based on evidence from the Taiga Plains.

Mixed forests with 25 to 40 percent deciduous trees, planted at 600 to 1,400 trees per hectare, deliver stronger and more durable climate cooling than dense evergreen monocultures.

A mixed stand of approximately 25 percent aspen generates stronger and more durable cooling than conifer-only stands by combining rapid early growth with sustained carbon retention.

In a warming boreal system, wildfire is the primary constraint on carbon durability, not growth rate or planting volume.

Partial harvesting followed by prompt mixed-species replanting maintains stronger and more stable climate returns than full clearcut cycles.

Publication Details

Ofosu, E., Dsouza, K. B., Amaogu, D. C., Pigeon, J., Boudreault, R., Shokri, N., Moreno-Cruz, J., Matin, M., Madani, K., Maghoul, P., and Leonenko, Y. (2026). From Carbon Accounting to Net Cooling: Securing the Albedo-Carbon Double Win in Canada’s Boreal Forest. United Nations University Institute for Water, Environment and Health (UNU-INWEH), Richmond Hill, Ontario, Canada. doi: 10.53328/INR26RPM001

Available for Interview

Interview requests should be submitted to media.inweh@unu.edu

About UNU-INWEH

Marking its 30th anniversary of operation in 2026, the United Nations University Institute for Water, Environment and Health (UNU-INWEH) is one of 13 institutions that make up the United Nations University (UNU), the academic arm of the UN. Known as ‘The UN’s Think Tank on Water’, UNU-INWEH addresses critical water, environmental, and health challenges around the world. Through research, training, capacity development, and knowledge dissemination, the institute contributes to solving pressing global sustainability and human security issues of concern to the UN and its Member States.

Headquartered in Richmond Hill, Ontario, UNU-INWEH has been hosted and supported by the Government of Canada since 1996. With a global mandate and extensive partnerships across UN entities, international organizations, and governments, UNU-INWEH operates through its UNU Hubs in Calgary, Hamburg, New York, Lund, and Pretoria, and an international network of affiliates.

DOI

10.53328/INR26RPM001

Article Title

From Carbon Accounting to Net Cooling: Securing the Albedo-Carbon Double Win in Canada’s Boreal Forest

Article Publication Date

20-Aug-2026

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Friday, August 21, 2026

Researchers identify the immune cells that keep a deadly fungus in check

Journal

DOI

Article Title

Mountain hayfields can filter nutrients and support clean water

Molecular 'bypasses' improve grass plants’s synthesis of lignin and starch, laying the early groundwork for evolutionary success

Journal

DOI

Method of Research

Article Title

Article Publication Date

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