Wednesday, April 03, 2024

AI helps to detect invasive Asian hornets

UNIVERSITY OF EXETER

VespAI Detection Prior to VespAI analysis — IMAGE:
VESPAI DETECTION PRIOR TO VESPAI ANALYSIS
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CREDIT: UNIVERSITY OF EXETER

Artificial Intelligence can be used to detect invasive Asian hornets and raise the alarm, new research shows.

University of Exeter researchers have developed VespAI, an automated system that attracts hornets to a monitoring station and captures standardised images using an overhead camera.

When an Asian hornet visits, VespAI can identify the species with almost perfect accuracy – allowing authorities to mount a rapid response.

Asian hornets (also known as yellow-legged hornets) have already invaded much of mainland Europe and parts of east Asia, and have recently been reported in the US states of Georgia and South Carolina.

The UK sits at the edge of the European invasion front, and with ongoing yearly incursions there is an urgent need for improved monitoring systems.

“Our goal was to develop something cost-effective and versatile, so anyone – from governments to individual beekeepers – could use it,” said Dr Thomas O’Shea-Wheller, from the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall.

“This study tested a prototype version, and the results were encouraging. VespAI shows promise as a robust early warning system to detect Asian hornet ingressions into new regions.”

VespAI uses a compact processor to operate, and remains dormant unless its sensors identify an insect within the size range of a hornet.

If this happens, the system’s AI algorithm activates, analysing the image to determine if it’s an Asian hornet (Vespa velutina), or native European hornet (Vespa crabro). If an Asian hornet is detected, the monitor then sends an image alert to the user, allowing them to confirm the identification.

At present, the UK response strategy depends upon people seeing, identifying and reporting Asian hornets. However, this has some limitations.

“Unfortunately, the majority of reports submitted are misidentified native species, meaning that the responsible agencies have to manually validate thousands of images every year – our system thus aims to provide a vigilant, accurate and automated surveillance capability to remediate this,” said Dr Peter Kennedy, who conceptualised the system.

“In some parts of Europe, detection relies on hornet trapping – but such traps kill a lot of native insects, and do little to impact Asian hornet numbers.

“VespAI does not kill non-target insects, and thus eliminates the environmental impact of trapping, while ensuring that live hornets can be caught and tracked back to the nest, which is the only effective way to destroy them.”

During the project, the system was tested extensively on the island of Jersey, which experiences high numbers of Asian hornet incursions due to its proximity to France.

While this exposed the monitor to both Asian hornets, European hornets and a variety of other insects, VespAI’s detection algorithm successfully distinguished between each of these, even when present in large numbers.

“That’s the benefit of our system – its high accuracy means that it won’t wrongly identify other species, or miss any Asian hornets that visit,” said Dr O’Shea-Wheller.

The research project included both biologists and data scientists from the University of Exeter’s Environment and Sustainability Institute, Centre for Ecology and Conservation and Institute for Data Science and Artificial Intelligence.

This year, the team will begin deploying additional prototypes in collaboration with Defra, the National Bee Unit, the British Beekeepers Association and Vita Bee Health.

With 2023 seeing record numbers of Asian hornet sightings in the UK, the system aims to bolster exclusion efforts at a potentially crucial juncture.

“The proposed device may prove a powerful tool in the early determination of the presence of Asian hornets in an area, and thereby fills an important gap,” said Alistair Christie, Senior Scientific Officer for Invasive Species in Jersey, and part of the collaborative testing effort.

The project was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), part of UKRI.

The paper, published in the journal Communications Biology, is entitled: “VespAI: a deep learning-based system for the detection of invasive hornets.”

VespAI Bait Station

CREDIT

Peter J. Kennedy

JOURNAL

Communications Biology

DOI

10.1038/s42003-024-05979-z

ARTICLE TITLE

VespAI: a deep learning-based system for the detection of invasive hornets

ARTICLE PUBLICATION DATE

3-Apr-2024

Machine learning enables viability of vertical-axis wind turbines

EPFL researchers have used a genetic learning algorithm to identify optimal pitch profiles for the blades of vertical-axis wind turbines, which despite their high energy potential, have until now been vulnerable to strong gusts of wind.

Peer-Reviewed Publication

ECOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE

Experimental VAWT blade — IMAGE:
EXPERIMENTAL VAWT BLADE
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CREDIT: © UNFOLD EPFL CC BY SA

If you imagine an industrial wind turbine, you likely picture the windmill design, technically known as a horizontal-axis wind turbine (HAWT). But the very first wind turbines, which were developed in the Middle East around the 8th century for grinding grain, were vertical-axis wind turbines (VAWT), meaning they spun perpendicular to the wind, rather than parallel.

Due to their slower rotation speed, VAWTs are less noisy than HAWTs and achieve greater wind energy density, meaning they need less space for the same output both on- and off-shore. The blades are also more wildlife-friendly: because they rotate laterally, rather than slicing down from above, they are easier for birds to avoid.

With these advantages, why are VAWTs largely absent from today’s wind energy market? As Sébastien Le Fouest, a researcher in the School of Engineering Unsteady Flow Diagnostics Lab explains, it comes down to an engineering problem – air flow control – that he believes can be solved with a combination of sensor technology and machine learning. In a paper recently published in Nature Communications, Le Fouest and UNFOLD head Karen Mulleners describe two optimal pitch profiles for VAWT blades, which achieve a 200% increase in turbine efficiency and a 77% reduction in structure-threatening vibrations.

“Our study represents, to the best of our knowledge, the first experimental application of a genetic learning algorithm to determine the best pitch for a VAWT blade,” Le Fouest says.

Turning an Achilles’ heel into an advantage

Le Fouest explains that while Europe’s installed wind energy capacity is growing by 19 gigawatts per year, this figure needs to be closer to 30 GW to meet the UN’s 2050 objectives for carbon emissions.

“The barriers to achieving this are not financial, but social and legislative – there is very low public acceptance of wind turbines because of their size and noisiness,” he says.

Despite their advantages in this regard, VAWTs suffer from a serious drawback: they only function well with moderate, continuous air flow. The vertical axis of rotation means that the blades are constantly changing orientation with respect to the wind. A strong gust increases the angle between air flow and blade, forming a vortex in a phenomenon called dynamic stall. These vortices create transient structural loads that the blades cannot withstand.

To tackle this lack of resistance to gusts, the researchers mounted sensors onto an actuating blade shaft to measure the air forces acting on it. By pitching the blade back and forth at different angles, speeds, and amplitudes, they generated series of ‘pitch profiles’. Then, they used a computer to run a genetic algorithm, which performed over 3500 experimental iterations. Like an evolutionary process, the algorithm selected for the most efficient and robust pitch profiles, and recombined their traits to generate new and improved ‘offspring’.

This approach allowed the researchers not only to identify two pitch profile series that contribute to significantly enhanced turbine efficiency and robustness, but also to turn the biggest weakness of VAWTs into a strength.

“Dynamic stall – the same phenomenon that destroys wind turbines – at a smaller scale can actually propel the blade forward. Here, we really use dynamic stall to our advantage by redirecting the blade pitch forward to produce power,” Le Fouest explains. “Most wind turbines angle the force generated by the blades upwards, which does not help the rotation. Changing that angle not only forms a smaller vortex – it simultaneously pushes it away at precisely the right time, which results in a second region of power production downwind.”

The Nature Communications paper represents Le Fouest’s PhD work in the UNFOLD lab. Now, he has received a Swiss National Science Foundation (SNSF) BRIDGE grant to build a proof-of-concept VAWT. The goal is to install it outdoors, so that it can be tested as it responds in real time to real-world conditions.

“We hope this air flow control method can bring efficient and reliable VAWT technology to maturity so that it can finally be made commercially available,” Le Fouest says.

This work benefited from the SNSF's "Assistant Professor (AP) Energy Grants" instrument. The call for proposals, launched between 2013 and 2016 as part of the Swiss government's Energy Strategy 2050, aimed to fund the launch of new energy-related research projects in newly opened laboratories. Read the SNSF press release.

JOURNAL

Nature Communications

DOI

10.1038/s41467-024-46988-0

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Optimal blade pitch control for enhanced vertical-axis wind turbine performance

ARTICLE PUBLICATION DATE

30-Mar-2024

A simple way to harvest more ‘blue energy’ from waves

AMERICAN CHEMICAL SOCIETY

As any surfer will tell you, waves pack a powerful punch. Now, we are one step closer to capturing the energy behind the ocean’s constant ebb and flow with an improved “blue energy” harvesting device. Researchers report in ACS Energy Letters that simply repositioning the electrode — from the center of a see-sawing liquid-filled tube to the end where the water crashes with the most force — dramatically increased the amount of wave energy that could be harvested.

The tube-shaped wave-energy harvesting device improved upon by the researchers is called a liquid–solid triboelectric nanogenerator (TENG). The TENG converts mechanical energy into electricity as water sloshes back and forth against the inside of the tube. One reason these devices aren’t yet practical for large-scale applications is their low energy output. Guozhang Dai, Kai Yin, Junliang Yan and colleagues aimed to increase a liquid–solid TENG’s energy harvesting ability by optimizing the location of the energy-collecting electrode.

The researchers used 16-inch clear plastic tubes to create two TENGs. Inside the first device, they placed a copper foil electrode at the center of the tube — the usual location in conventional liquid–solid TENGs. For the new design, they inserted a copper foil electrode at one end of the tube. The researchers then filled the tubes a quarter of the way with water and sealed the ends. A wire connected the electrodes to an external circuit.

Placing both devices on a benchtop rocker moved water back and forth within the tubes and generated electrical currents by converting mechanical energy — the friction from water hitting or sliding against the electrodes — into electricity. Compared to the conventional design, the researchers found that the optimized design increased the device’s conversion of mechanical energy to electrical current 2.4 times. In another experiment, the optimized TENG blinked an array of 35 LEDs on and off as water entered the section of the tube covered by the electrode and then flowed away, respectively. The researchers say these demonstrations lay the foundation for larger scale blue-energy harvesting from ocean waves and show their device’s potential for other applications like wireless underwater signaling communications.

The authors acknowledge funding from the National Natural Science Foundation of China and the National Key Research and Development Program of China, and acknowledge computing resources from the High Performance Computing Center of Central South University.

The paper’s abstract will be available on April 3 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acsenergylett.4c00072

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The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.

JOURNAL

ACS Energy Letters

DOI

10.1021/acsenergylett.4c00072

ARTICLE TITLE

Space Volume Effect in Tube Liquid–Solid Triboelectric Nanogenerator for Output Performance Enhancement

ARTICLE PUBLICATION DATE

3-Apr-2024

Water-based paints: Less stinky, but some still contain potentially hazardous chemicals

AMERICAN CHEMICAL SOCIETY

Choosing paint for your home brings a lot of options: What kind of paint, what type of finish and what color? Water-based paints have emerged as “greener” and less smelly than solvent-based options. And they are often advertised as containing little-to-no volatile organic compounds (VOCs). But, according to research published in ACS’ Environmental Science & Technology Letters, some of these paints do contain compounds that are considered VOCs, along with other chemicals of emerging concern.

Paint consists of four ingredients: pigments, binders, additives and a liquid. If the liquid is water — as in latex and some acrylic paints — it’s classified as a water-based paint, rather than solvent-based. Historically, solvent-based paints were easy to apply and durable, though they released foul-smelling VOCs into the air both during and after application, stinking up a newly painted room. These airborne VOCs can cause respiratory irritation and headaches, among other potential health problems, especially in high concentrations or over long periods of time. Despite water-based paints sporting labels with “zero-” or “low-VOC,” their formulations could contain potentially dangerous chemicals of their own. So, Ying Xu and colleagues wanted to understand more about these paints’ formulations. The team notes that there are differing definitions of what constitutes a VOC, some of which are stricter than others, including the World Health Organization’s definition used in this research.

The team collected 40 water-based paints from around the world, all ranked among the top 70 most-sold brands, and many labelled as zero- or low-VOC. Both dry and wet samples were analyzed by gas chromatography-mass spectrometry to determine their composition.

Twenty semi-volatile organic compounds were identified in concentrations ranging from 10 to 35,000 parts per million. While less likely to be in a gaseous form, these can still persist indoors for years, often incorporated into dust.
Endocrine-disrupting phthalates, which act as binders, were largely absent in the tested paints. However, several phthalate-replacement chemicals were detected — their toxicities are still being assessed.
Nearly half the analyzed samples contained measurable amounts of isothiazolinones — preservatives that have been linked to skin irritation and asthmatic symptoms.
In 24 of the wet paint samples advertised as either zero- or low-VOC, 11 different VOCs were detected at concentrations up to 20,000 parts per million.

These concentrations represent the chemical composition within the paint, not the air. Further studies are required to understand how much of these potentially hazardous compounds become airborne as painted surfaces are drying. The researchers say that this work could allow for the design of safer paint products in the future.

The authors acknowledge funding from the National Natural Science Foundation of China.

The paper’s abstract will be available on April 3 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.estlett.4c00052

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To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.

JOURNAL

Environmental Science & Technology Letters

DOI

10.1021/acs.estlett.4c00052

ARTICLE TITLE

Chemicals of Emerging Concern in Water-Based Paint Products

ARTICLE PUBLICATION DATE

3-Apr-2024

Testing environmental water to monitor COVID-19 spread in unsheltered encampments

AMERICAN CHEMICAL SOCIETY

To better understand COVID-19’s spread during the pandemic, public health officials expanded wastewater surveillance. These efforts track SARS-CoV-2 levels and health risks among most people, but they miss people who live without shelter, a population particularly vulnerable to severe infection. To fill this information gap, researchers reporting in ACS’ Environmental Science & Technology Letters tested flood-control waterways near unsheltered encampments, finding similar transmission patterns as in the broader community and identifying previously unseen viral mutations.

In recent years, testing untreated wastewater for SARS-CoV-2 incidence and dominant viral variants, as well as other pathogens, has been vital to helping public health officials determine infectious disease transmission in local communities. Yet, this monitoring only captures information on viruses shed from human feces and urine in buildings that are connected to local sewage infrastructure. Beyond the pandemic’s impact on human health, it also exacerbated socioeconomic difficulties and increased the number of people experiencing homelessness and living in open-air encampments without access to indoor bathrooms. To understand the prevalence of COVID-19 among people who live unsheltered, Edwin Oh and colleagues tested for SARS-CoV-2 in waterways near encampments outside Las Vegas from December 2021 through July 2022.

Using quantitative polymerase chain reaction, the researchers identified SARS-CoV-2 RNA in more than 25% of the samples tested from two flood-control channels. The highest detection frequency over the study period aligned with Las Vegas’ first wave of omicron variant infections, as confirmed through parallel testing at a local wastewater treatment plant. The researchers say these results suggest a similar level of transmission was occurring within the unsheltered community as it was among the general population. Then the researchers conducted whole genome sequencing to identify the SARS-CoV-2 variants in the waterways. These samples largely contained the same variants identified in the broader community. Deeper computational analysis of the viral sequences identified three novel viral spike protein mutations in some waterway samples, but the researchers have not yet examined what impact these mutations might have on viral function or clinical outcomes. Regardless, the ability to detect and identify SARS-CoV-2 in environmental water samples could help improve public health measures for a community that is often underrepresented in current surveillance methods. The researchers also say monitoring waterways could warn health officials of unexpected variants circulating in the community.

The authors acknowledge funding from the National Institutes of Health, the Nevada Governor’s Office of Economic Development, the Centers for Disease Control and Prevention, and the Water Resources Research Institute of the United States Geological Survey.

The paper’s abstract will be available on April 3 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.estlett.3c00938

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To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.

JOURNAL

Environmental Science & Technology Letters

DOI

10.1021/acs.estlett.3c00938

ARTICLE TITLE

Environmental Surveillance of Flood Control Infrastructure Impacted by Unsheltered Individuals Leads to the Detection of SARS-CoV‑2 and Novel Mutations in the Spike Gene

ARTICLE PUBLICATION DATE

3-Apr-2024

California leads U.S. emissions of little-known greenhouse gas

State emits more than rest of country combined, new study finds

Peer-Reviewed Publication

JOHNS HOPKINS UNIVERSITY

Global Sulfuryl Fluoride Emissions — IMAGE:
THE UNITED STATES IS RESPONSIBLE FOR AS MUCH AS 17% OF THE GLOBAL EMISSIONS OF SULFURYL FLUORIDE, A POTENT GREENHOUSE GAS. ABOUT 60-85% OF U.S. EMISSIONS COME FROM CALIFORNIA, ACCORDING TO A STUDY PUBLISHED IN *COMMUNICATIONS EARTH & ENVIRONMENT*
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CREDIT: KHAMAR HOPKINS/JOHNS HOPKINS UNIVERSITY

California, a state known for its aggressive greenhouse gas reduction policies, is ironically the nation’s greatest emitter of one: sulfuryl fluoride.

As much as 17% of global emissions of this gas, a common pesticide for treating termites and other wood-infesting insects, stem from the United States. The majority of those emissions trace back to just a few counties in California, finds a new study led by Johns Hopkins University.

“When we finally mapped it out, the results were puzzling because the emissions were all coming from one place,” said co-author Scot Miller, an assistant professor of environmental health and engineering at Johns Hopkins who studies greenhouse gases and air pollutants. “Other greenhouse gases like carbon dioxide and methane are found everywhere across the U.S. On our sulfuryl fluoride map, only California lit up like a Christmas tree.”

Miller and lead author Dylan Gaeta, a PhD candidate at Johns Hopkins, analyzed more than 15,000 air samples collected between 2015 and 2019 by NOAA Global Monitoring Laboratory scientists. The researchers factored in wind speed, direction, and other meteorological variables to trace the chemicals back to their point of origin.

The team found 60-85% of sulfuryl fluoride emissions in the U.S. come from California, primarily Los Angeles, Orange, and San Diego counties, despite California being a national leader in reducing greenhouse gas emissions, including publishing a comprehensive plan to achieve net-zero emissions by 2045.

“We can now show not only where but also how and why this gas is being emitted,” Gaeta said. “In order to get to net-zero emissions, we need a complete inventory of what greenhouse gases are out there.”

The findings published today in Communications Earth & Environment.

First approved by the U.S. Environmental Protection Agency for use as a pesticide in 1959, sulfuryl fluoride gained popularity after countries around the world agreed to phase out more reactive fumigants that were depleting the ozone layer, the researchers said.

Because California has kept thorough records of pesticide use, the team was able to attribute the vast majority, roughly 85% of the state’s sulfuryl fluoride emissions, to structural fumigation—the practice of sealing an infested structure with an airtight tent, pumping gas into the tent to eradicate the pests, and afterward venting the gas directly into the atmosphere. Roughly 15% came from agricultural and commodities fumigation.

Once emitted, the gas spreads and stays for more than 40 years in the atmosphere, where it contributes to global warming by trapping heat and sending it back down to the Earth’s surface, the researchers said. Average concentrations of sulfuryl fluoride in the atmosphere are low; however, humans have been emitting the man-made gas for decades at a rate faster than it can breakdown naturally.

“Without some form of intervention, sulfuryl fluoride is going to keep accumulating in our atmosphere. For most greenhouse gases, California has been very intentional about how it’s going to reduce emissions,” Gaeta said. “This one has slipped under the radar.”

Efforts to reduce greenhouse gas emissions generally focus on carbon because it poses the greatest threat to global warming. But, Miller said, researchers are working to get a more complete picture of the risks from other greenhouse gases.

Sulfuryl fluoride is one of the few treatments to rid buildings of drywood termites, a common regional pest that can form colonies in high, hard-to-reach parts of wooden structures. It’s also used at shipping ports to kill pests before they can hitch a ride to other parts of the world.

“It really is a double-edged sword. Sulfuryl fluoride is less harmful than the banned fumigants, but it also contributes to global warming,” Miller said. “California’s track record shows that it’s been looking at out-of-the-box, creative ways to reduce its greenhouse gas emissions. I think knowing better what the emissions are and what impact they have will give the state the information it needs to help holistically develop greenhouse gas reduction strategies.”

The researchers shared findings with the California Air Resources Board and the Bay Area Air Quality Management District.

This work was made possible by NSF program grants 2121641 and 2121739; NOAA grants NA21OAR4310233, NA21OAR4310234, NA14OAR0110139, NA14OAR0110140, and NA17OAR4320101; and NASA grant NNX15AJ06G.

Authors include: Johns Hopkins PhD candidate Mingyang Zhang; Scripps Institution of Oceanography researcher Jens Mühle; NOAA researchers Isaac J. Vimont, John B. Miller, Kathryn McKain, Lei Hu, Bianca C. Baier, Molly Crotwell, and Benjamin R. Miller; and Jianing Bao, a former Johns Hopkins graduate student.

Graphic: The United States is responsible for as much as 17% of the global emissions of sulfuryl fluoride, a potent greenhouse gas. About 60-85% of U.S. emissions come from California, according to a study published in Communications Earth & Environment. Credit/ Khamar Hopkins, Johns Hopkins University

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JOURNAL

Communications Earth & Environment

DOI

10.1038/s43247-024-01294-x

ARTICLE TITLE

California dominatesU.S. emissions of the pesticide and potent greenhouse gas sulfuryl fluoride

ARTICLE PUBLICATION DATE

3-Apr-2024

Discovery could end global amphibian pandemic

What infects the infection?

UNIVERSITY OF CALIFORNIA - RIVERSIDE

Panamanian golden frog — IMAGE:
PANAMANIAN GOLDEN FROG IS NEARING EXTINCTION.
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CREDIT: BRIAN GRATWICKE/U.S. FISH & WILDLIFE SERVICE

A fungus devastating frogs and toads on nearly every continent may have an Achilles heel. Scientists have discovered a virus that infects the fungus, and that could be engineered to save the amphibians.

The fungus, Batrachochytrium dendrobatidis or Bd, ravages the skin of frogs and toads, and eventually causes heart failure. To date it has contributed to the decline of over 500 amphibian species, and 90 possible extinctions including yellow-legged mountain frogs in the Sierras and the Panamanian golden frog.

A new paper in the journal Current Biology documents the discovery of a virus that infects Bd, and which could be engineered to control the fungal disease.

The UC Riverside researchers who found the virus are excited about the implications of their discovery. In addition to helping them learn about how fungal pathogens rise and spread, it offers the hope of ending what they call a global amphibian pandemic.

“Frogs control bad insects, crop pests, and mosquitoes. If their populations all over the world collapse, it could be devastating,” said UCR microbiology doctoral student and paper author Mark Yacoub.

“They’re also the canary in the coal mine of climate change. As temperatures get warmer, UV light gets stronger, and water quality gets worse, frogs respond to that. If they get wiped out, we lose an important environmental signal,” Yacoub said.

Bd was not prevalent before the late 1990s, but then, “all of a sudden frogs started dying,” Yacoub said.

When they found the Bd-infecting virus, Yacoub and UCR microbiology professor Jason Stajich had been working on the population genetics of Bd, hoping to gain a better understanding about where it came from and how it is mutating.

“We wanted to see how different strains of fungus differ in places like Africa, Brazil, and the U.S., just like people study different strains of COVID-19,” Stajich said. To do this, the researchers used DNA sequencing technology. As they examined the data, they noticed some sequences that did not match the DNA of the fungus.

“We realized these extra sequences, when put together, had the hallmarks of a viral genome,” Stajich said.

Previously, researchers have looked for Bd viruses but did not find them. The fungus itself is hard to study because complex procedures are required to keep it alive in a laboratory.

“It is also a hard fungus to keep track of because they have a life stage where they’re motile, they have a flagellus, which resembles a sperm tail, and they swim around,” Stajich said.

Additionally, the virus that infects Bd was hard to find because most known viruses that infect fungi, called mycoviruses, are RNA viruses. However, this virus is a single-stranded DNA virus. By studying the DNA, the researchers could see the virus stuck in the genome of the fungus.

It appears that only some strains of the fungus have the virus in their genome. But the infected ones seem to behave differently than the ones that don’t. “When these strains possess the virus they produce fewer spores, so it spreads more slowly. But they also might become more virulent, killing frogs faster,” Stajich said.

Right now, the virus is essentially trapped inside the fungal genome. The researchers would eventually like to clone the virus and see if a manually infected strain of Bd also produces fewer spores.

“Because some strains of the fungus are infected and some are not, this underscores the importance of studying multiple strains of a fungal species,” Yacoub said.

Moving forward, the researchers are looking for insights into the ways that the virus operates. “We don’t know how the virus infects the fungus, how it gets into the cells,” Yacoub said. “If we’re going to engineer the virus to help amphibians, we need answers to questions like these.”

In some places, it appears there are a few amphibian species acquiring resistance to Bd. “Like with COVID, there is a slow buildup of immunity. We are hoping to assist nature in taking its course,” Yacoub said.

Spore producing structures of the fungus Bd.

CREDIT

Mark Yacoub/UCR

JOURNAL

Current Biology

DOI

10.1016/j.cub.2024.02.062

ARTICLE TITLE

An endogenous DNA virus in an amphibian-killing fungus associated with pathogen genotype and virulence