Bacteria produce chemicals called bacteriocins to kill microbial competitors. These chemicals can serve as natural preservatives by killing potentially dangerous pathogens in food. Lanthipeptides, a class of bacteriocins with especially potent antimicrobial properties, are widely used by the food industry and have become known as “lantibiotics” (a scientific portmanteau of lanthipeptide and antibiotics).

Despite their widespread use, however, little is known about how these lantibiotics affect the gut microbiomes of people who consume them in food. Microbes in the gut live in a delicate balance, and commensal bacteria provide important benefits to the body by breaking down nutrients, producing metabolites, and — importantly — protecting against pathogens. If too many commensals are indiscriminately killed off by antimicrobial food preservatives, opportunistic pathogenic bacteria might take their place and wreak havoc — a result no better than eating contaminated food in the first place.

Effects on good and bad bacteria

A new study published in ACS Chemical Biology by scientists from the University of Chicago found that one of the most common classes of lantibiotics has potent effects both against pathogens and against the commensal gut bacteria that keep us healthy.

Nisin is a popular lantibiotic used in everything from beer and sausage to cheese and dipping sauces. It is produced by bacteria that live in the mammary glands of cows, but microbes in the human gut produce similar lantibiotics too. Zhenrun “Jerry” Zhang, PhD, a postdoctoral scholar in the lab of Eric Pamer, MD, the Donald F. Steiner Professor of Medicine and Director of the Duchossois Family Institute at UChicago, wanted to study the impact of such naturally-produced lantibiotics on commensal gut bacteria.

“Nisin is, in essence, an antibiotic that has been added to our food for a long time, but how it might impact our gut microbes is not well studied,” Zhang said. “Even though it might be very effective in preventing food contamination, it might also have a greater impact on our human gut microbes.”

He and his colleagues mined a public database of human gut bacteria genomes and identified genes for producing six different gut-derived lantibiotics that closely resemble nisin, four of which were new. Then, in collaboration with Wilfred A. van der Donk, PhD, the Richard E. Heckert Endowed Chair in Chemistry at the University of Illinois Urbana-Champaign, they produced versions of these lantibiotics to test their effects on both pathogens and commensal gut bacteria. The researchers found that while the different lantibiotics had varying effects, they killed pathogens and commensal bacteria alike.

“This study is one of the first to show that gut commensals are susceptible to lantibiotics, and are sometimes more sensitive than pathogens,” Zhang said. “With the levels of lantibiotics currently present in food, it’s very probable that they might impact our gut health as well.”

Harnessing the power of lantibiotics

Zhang and his team also studied the structure of peptides in the lantibiotics to better understand their activity, in the interest of learning how to use their antimicrobial properties for good. For example, in another study, the Pamer lab showed that a consortium of four microbes, including one that produces lantibiotics, help protect mice against antibiotic-resistant Enterococcus infections. They are also studying the prevalence of lantibiotic-resistant genes across different populations of people to better understand how such bacteria can colonize the gut under different conditions and diets.

“It seems that lantibiotics and lantibiotic-producing bacteria are not always good for health, so we are looking for ways to counter the potential bad influence while taking advantage of their more beneficial antimicrobial properties,” Zhang said.

The study, “Activity of Gut-derived Nisin-like Lantibiotics Against Human Gut Pathogens and Commensals,” was supported by the GI Research Foundation, the Howard Hughes Medical Institute, the National Institutes of Health (grants R01AI095706, P01 CA023766, U01 AI124275, and R01 AI042135) and the Duchossois Family Institute at UChicago. Additional authors include Chunyu Wu, Ryan Moreira, and Darian Dorantes from the Univeristy of Illinois Urbana-Champaign, and Téa Pappas, Anitha Sundararajan, and Huaiying Lin from UChicago.

Seeing that structure snap open and shut in mere millionths of a second is giving Duke Human Vaccine Institute (DHVI) investigators a new handle on the surface of the virus that could lead to broadly neutralizing antibodies for an AIDS vaccine. Their findings appear Feb. 2 in Science Advances.

Being able to attach an antibody specifically to this little structure that would prevent it from popping open would be key. Their findings appear Feb. 2 in Science Advances.

The moving part is a structure called envelope glycoprotein, and AIDS researchers have been trying to figure it out for years because it is a key part of the virus’ ability to dock on a T-cell receptor known as CD4. Many parts of the envelope are constantly moving to evade the immune system, but vaccine immunogens are designed to stay relatively stable.

“Everything that everybody’s done to try to stabilize this (structure) won’t work, because of what we learned,” said lead author Rory Henderson, a structural biologist who is an associate professor of medicine in DHVI. “It’s not that they did something wrong; it’s just that we didn’t know it moves this way.”

Postdoctoral researcher and study co-author Ashley Bennett offers a play-by-play: As the virus feels for its best attachment point on a human T-cell, the host cell’s CD4 receptor is the first thing it latches onto. That connection is what then triggers the envelope structure to pop open, which in turn, exposes a co-receptor binding site “and that’s the event that actually matters.”

Once both molecules of the virus are bound to the cell membrane, the process of injecting viral RNA can begin. “If it gets inside the cell, your infection is now permanent,” Henderson said.

“If you get infected, you’ve already lost the game because it’s a retrovirus,” Bennett agrees.

The moving structure they found protects the sensitive co-receptor binding site on the virus. “It’s also a latch to keep it from springing until it’s ready to spring,” Henderson said. Keeping it latched with a specific antibody would stop the process of infection.

To see the viral parts in various states of open, closed and in-between, Bennett and Henderson used an electron accelerator at the Argonne National Laboratory outside Chicago that produces X-rays in wavelengths that can resolve something as small as a single atom. But this expensive, shared equipment is in high demand. The AIDS researchers were awarded three 120-hour blocks of time with the synchrotron to try to get as much data as they could in marathon sessions. “Basically, you just go until you can’t anymore,” Bennett said.

Earlier research elsewhere had argued that antibodies were being designed for the wrong shapes on the virus and this work shows that was probably correct.

“The question has been ‘why, when we immunize, are we getting antibodies to places that are supposed to be blocked?'” Henderson said. Part of the answer should lie in this particular structure and its shape-shifting.

“It’s the interplay between the antibody binding and what this shape is that’s really critical about the work that we did,” Henderson said. “And that led us to design an immunogen the day we got back from the first experiment. We think we know how this works.”

This research was supported by the National Institutes of Health (UM1AI14437, R01AI145687, U54AI170752, P30 GM124169, S10OD018483), the Department of Energy (DE-AC02-06CH11357) and the DOE Office of Biological and Environmental Research.

Drylands make up 40 percent of the Earth’s landmass and are places where water is the limiting resource for life. They often display a characteristic clustering of vegetation surrounded by bare soil — patterns that are easy to spot in aerial images. The new study, led by SFI External Professor Sonia Kéfi, who is a researcher at CNRS in France, finds that not only are these spatial patterns caused by the stressful environmental conditions of drylands, but they are also a critical adaptation that allows drylands to function in changing conditions. When a dryland ecosystem tips into a degraded state, the spatial patterns disappear.

“Many people have the idea that ‘interesting’ ecosystems are places like the Amazon, and that drylands are poor in some way,” says SFI External Professor Ricard Solé (Pompeu Fabra University), a co-author on the paper. “But they can be very rich. They are responsible for managing how water is being retained or not in these habitats, and are important for CO2 exchange.” Beyond their ecological importance, drylands are also home to one-third of the world’s human population, making them important economically and culturally.

In healthy dryland ecosystems, islands of vegetation create oases where conditions are a bit better than the rest of the landscape. There’s more water, more nutrients, and more shade. If an ecosystem’s climate becomes drier, those clusters tend to move further apart.

And this, says Kéfi, is a double-edged sword. While improving local conditions, these clusters also create spaces without vegetation — harsh places where a single plant would not survive on its own. If conditions become too harsh, the ecosystem can reach a tipping point into desertification.

Kéfi and her colleagues wondered if aerial images, and their evidence of changes in spatial patterns, could themselves indicate the health or level of degradation in a given plot of land.

“In theory, we could tell something about the ecosystem from the sky — that’s what the models predict, in very broad terms,” says Kéfi. To test this, the team paired aerial images with soil and vegetation data gathered from 115 dryland ecosystems across 13 different countries. “This on-the-ground data shows us where one ecosystem is healthier or functioning better than other ecosystems.” Using the two types of data, the team could test the predictions of the model against real-world observations.

“Our results represent a significant advance in the development of tools for the management and preservation of dryland ecosystems in a warmer, drier world,” says Kéfi. “More specifically, changes in spatial vegetation patterns (or the lack thereof) could be used as indicators of degradation.”

According to Solé, the study offers, for the first time, real validation that the model correctly predicts the nonlinear dynamics of what has been unfolding in dryland ecosystems. “The beauty of this work is that it reveals something that goes beyond the pattern-forming problem. You can talk about ecosystem health in ways that are not metaphoric, and it opens new interesting questions about how to address the future of these ecosystems,” he says.

The authors hope their work will make it easier to spot degrading systems that might be approaching a tipping point. And, because vegetation patterning seems to also be key in other natural systems, such as microbial communities or coastal wetlands, their results could have implications for systems beyond arid zones.

3D surface imaging is a common tool used in smartphone facial recognition, as well as in computer vision and autonomous driving. These systems typically consist of a dot projector that contains multiple components: a laser, lenses, a light guide and a diffractive optical element (DOE). The DOE is a special kind of lens that breaks the laser beam into an array of about 32,000 infrared dots. So, when a person looks at a locked screen, the facial recognition system projects an array of dots onto most of their face, and the device’s camera reads the pattern created to confirm the identity. However, dot projector systems are relatively large for small devices such as smartphones. So, Yu-Heng Hong, Hao-Chung Kuo, Yao-Wei Huang and colleagues set out to develop a more compact facial recognition system that would be nearly flat and require less energy to operate.

To do this, the researchers replaced a traditional dot projector with a low-power laser and a flat gallium arsenide surface, significantly reducing the imaging device’s size and power consumption. They etched the top of this thin metallic surface with a nanopillar pattern, which creates a metasurface that scatters light as it passes through the material. In this prototype, the low-powered laser light scatters into 45,700 infrared dots that are projected onto an object or face positioned in front of the light source. Like the dot projector system, the new system incorporates a camera to read the patterns that the infrared dots created.

In tests of the prototype, the system accurately identified a 3D replica of Michelangelo’s David by comparing the infrared dot patterns to online photos of the famous statue. Notably, it accomplished this using five to 10 times less power and on a platform with a surface area about 230 times smaller than a common dot-projector system. The researchers say their prototype demonstrates the usefulness of metasurfaces for effective small-scale low-power imaging solutions for facial recognition, robotics and extended reality.

The authors acknowledge funding from Hon Hai Precision Industry, the National Science and Technology Council in Taiwan, and the Ministry of Education in Taiwan.

In recent years, the functional and mechanical properties of low-dimensional metals, including nanoparticles, nanotubes and nanosheets, have garnered attention for their potential applications in small-scale devices, such as sensors, nano-robots and metamaterials. However, most metals are electrochemically active and susceptible to oxidation in ambient environments, which often degrades their properties and functionalities.

“Metallic nanomaterials have a high surface-to-volume ratio, which can be up to 10⁸m^-1. So in principle, they are expected to be particularly prone to oxidation,” said Professor Yang Yong, in the Department of Mechanical Engineering at CityU, who led the research team together with his collaborators. “To use low-dimensional metals to develop next-generation devices and metamaterial, we must thoroughly understand the adverse effects of oxidation on the properties of these nanometals and then find a way to overcome them.”

Therefore, Professor Yang and his team investigated oxidation in nanometals, and in sharp contrast to their expectation, they found that severely oxidized metallic glass nanotubes and nanosheets can attain an ultrahigh recoverable elastic strain of up to about 14% at room temperature, which outperforms bulk metallic glasses, metallic glass nanowires, and many other super-elastic metals.

They made metallic glass nanotubes with an average wall thickness of just 20nm, and fabricated nanosheets from different substrates, such as sodium chloride, polyvinyl alcohol and conventional photoresist substrates, with different levels of oxygen concentration.

They then conducted 3D atom probe tomography (APT) and electron energy loss spectroscopy measurements. In both the results, oxides were dispersed within the metallic glass nanotubes and nanosheets, unlike conventional bulk metals, in which a solid oxide layer forms on the surface. As the oxygen concentration in the samples increased owing to metal-substrate reactions, connected and percolating oxide networks were formed inside the nanotubes and nanosheets.

In-situ microcompression measurements also revealed that the severely oxidized metallic glass nanotubes and nanosheets exhibited a recoverable strain of 10-20%, which was several times more than that of most conventional superelastic metals, such as shape memory alloys and gum metals. The nanotubes also had an ultra-low elastic modulus of about 20-30 GPa.

To understand the mechanism behind this, the team conducted atomistic simulations, which indicated that the superelasticity originates from severe oxidation in the nanotubes and can be attributed to the formation of a damage-tolerant percolation network of nano-oxides in the amorphous structure. These oxide networks not only restrict atomic-scale plastic events during loading, but also lead to the recovery of elastic rigidity on unloading in metallic glass nanotubes.

“Our research introduces a nano-oxide engineering approach for low-dimensional metallic glasses. The morphology of nano-oxides within metallic-glass nanotubes and nanosheets can be manipulated by adjusting the oxide concentration, ranging from isolated dispersions to a connected network,” said Professor Yang.

“With this approach, we can develop a class of heterogeneous nanostructured ceramic-metal composites by blending metals with oxides at the nanoscale. Such composites have great potential for various future commercial applications and nanodevices working in harsh environments, such as sensors, medical devices, micro- and nano-robots, springs and actuators,” he added.

There has been significant progress in the field of quantum computing. Big global players, such as Google and IBM, are already offering cloud-based quantum computing services. However, quantum computers cannot yet help with problems that occur when standard computers reach the limits of their capacities because the availability of qubits or quantum bits, i.e., the basic units of quantum information, is still insufficient. One of the reasons for this is that bare qubits are not of immediate use for running a quantum algorithm.

While the binary bits of customary computers store information in the form of fixed values of either 0 or 1, qubits can represent 0 and 1 at one and the same time, bringing probability as to their value into play. This is known as quantum superposition. This makes them very susceptible to external influences, which means that the information they store can readily be lost. In order to ensure that quantum computers supply reliable results, it is necessary to generate a genuine entanglement to join together several physical qubits to form a logical qubit. Should one of these physical qubits fail, the other qubits will retain the information. However, one of the main difficulties preventing the development of functional quantum computers is the large number of physical qubits required.

Advantages of a photon-based approach

Many different concepts are being employed to make quantum computing viable. Large corporations currently rely on superconducting solid-state systems, for example, but these have the disadvantage that they only function at temperatures close to absolute zero. Photonic concepts, on the other hand, work at room temperature. Single photons usually serve as physical qubits here. These photons, which are, in a sense, tiny particles of light, inherently operate more rapidly than solid-state qubits but, at the same time, are more easily lost. To avoid qubit losses and other errors, it is necessary to couple several single-photon light pulses together to construct a logical qubit — as in the case of the superconductor-based approach.

A qubit with the inherent capacity for error correction

Researchers of the University of Tokyo together with colleagues from Johannes Gutenberg University Mainz (JGU) in Germany and Palacký University Olomouc in the Czech Republic have recently demonstrated a new means of constructing a photonic quantum computer. Rather than using a single photon, the team employed a laser-generated light pulse that can consist of several photons. “Our laser pulse was converted to a quantum optical state that gives us an inherent capacity to correct errors,” stated Professor Peter van Loock of Mainz University. “Although the system consists only of a laser pulse and is thus very small, it can — in principle — eradicate errors immediately.” Thus, there is no need to generate individual photons as qubits via numerous light pulses and then have them interact as logical qubits. “We need just a single light pulse to obtain a robust logical qubit,” added van Loock. To put it in other words, a physical qubit is already equivalent to a logical qubit in this system — a remarkable and unique concept. However, the logical qubit experimentally produced at the University of Tokyo was not yet of a sufficient quality to provide the necessary level of error tolerance. Nonetheless, the researchers have clearly demonstrated that it is possible to transform non-universally correctable qubits into correctable qubits using the most innovative quantum optical methods.

The corresponding research results have recently been published in Science. They are based on a collaboration going back some 20 years between the experimental group of Akira Furusawa in Japan and the theoretical team of Peter van Loock in Germany.

Jonathan Brande, a doctoral candidate in the ExoLab at the University of Kansas, has just published findings in the open-access scientific journal The Astrophysical Journal Letters showing new atmospheric detail in a set of 15 exoplanets similar to Neptune. While none could support humanity, a better understanding of their behavior might help us to understand why we don’t have a small Neptune, while most solar systems seem to feature a planet of this class.

“Over the past several years at KU, my focus has been studying the atmospheres of exoplanets through a technique known as transmission spectroscopy,” Brande said. “When a planet transits, meaning it moves between our line of sight and the star it orbits, light from the star passes through the planet’s atmosphere, getting absorbed by the various gases present. By capturing a spectrum of the star — passing the light through an instrument called a spectrograph, akin to passing it through a prism — we observe a rainbow, measuring the brightness of different constituent colors. Varied areas of brightness or dimness in the spectrum reveal the gases absorbing light in the planet’s atmosphere.”

With this methodology, several years ago Brande published a paper concerning the “warm Neptune” exoplanet TOI-674 b, where he presented observations indicating the presence of water vapor in its atmosphere. These observations were part of a broader program led by Brande’s adviser, Ian Crossfield, associate professor of physics & astronomy at KU, to observe atmospheres of Neptune-sized exoplanets.

“We want to comprehend the behaviors of these planets, given that those slightly larger than Earth and smaller than Neptune are the most common in the galaxy,” Brande said.

This recent ApJL paper summarizes observations from that program, incorporating data from additional observations to address why some planets appear cloudy while others are clear.

“The goal is to explore the physical explanations behind the distinct appearances of these planets,” Brande said.

Brande and his co-authors took special note of regions where exoplanets tend to form clouds or hazes high up in their atmosphere. When such atmospheric aerosols are present, the KU researcher said hazes can block the light filtering through the atmosphere.

“If a planet has a cloud right above the surface with hundreds of kilometers of clear air above it, starlight can easily pass through the clear air and be absorbed only by the specific gases in that part of the atmosphere,” Brande said. “However, if the cloud is positioned very high, clouds are generally opaque across the electromagnetic spectrum. While hazes have spectral features, for our work, where we focus on a relatively narrow range with Hubble, they also produce mostly flat spectra.”

According to Brande, when these aerosols are present high in the atmosphere, there’s no clear path for light to filter through.

“With Hubble, the single gas we’re most sensitive to is water vapor,” he said. “If we observe water vapor in a planet’s atmosphere, that’s a good indication that there are no clouds high enough to block its absorption. Conversely, if water vapor is not observed and only a flat spectrum is seen, despite knowing that the planet should have an extended atmosphere, it suggests the likely presence of clouds or hazes at higher altitudes.”

Brande led the work of an international team of astronomers on the paper, including Crossfield at KU and collaborators from the Max Planck Institute in Heidelberg, Germany, a cohort led by Laura Kreidberg, and investigators at the University of Texas, Austin, led by Caroline Morley.

Brande and his co-authors approached their analysis differently than previous efforts by focusing on determining the physical parameters of the small-Neptune atmospheres. In contrast, previous analyses often involved fitting a single model spectrum to observations.

“Typically, researchers would take an atmospheric model with pre-computed water content, scale and shift it to match observed planets in their sample,” Brande said. “This approach indicates whether the spectrum is clear or cloudy but provides no information about the amount of water vapor or the location of clouds in the atmosphere.”

Instead, Brande employed a technique known as “atmospheric retrieval.”

“This involved modeling the atmosphere across various planet parameters such as water vapor quantity and cloud location, iterating through hundreds and thousands of simulations to find the best fit configuration,” he said. “Our retrievals gave us a best-fit model spectrum for each planet, from which we calculated how cloudy or clear the planet appeared to be. Then, we compared those measured clarities to a separate suite of models by Caroline Morley, which let us see that our results are in line with expectations for similar planets. In examining cloud and haze behavior, our models indicated that clouds were a better fit than hazes. The sedimentation efficiency parameter, reflecting cloud compactness, suggested observed planets had relatively low sedimentation efficiencies, resulting in fluffy clouds. These clouds, made up of particles like water droplets, remained lofted in the atmosphere due to their low settling tendency.”

Brande’s findings provide insights into the behavior of these planetary atmospheres and caused “substantial interest” when he presented them at a recent meeting of the American Astronomical Society.

Other findings

Moreover, Brande is part of an international observation program, led by Crossfield, that just announced findings of water vapor on GJ 9827d — a planet as hot as Venus 97 light-years from Earth in the constellation Pisces.

The observations, made with the Hubble Space Telescope, show the planet may be just one example of water-rich planets in the Milky Way. They were announced by a team led by Pierre-Alexis Roy of the Trottier Institute for Research on Exoplanets at Université de Montréal.

“We were searching for water vapor on the atmospheres of sub-Neptune-type planets,” Brande said. “Pierre-Alexis’ paper is the latest from that main effort because it took approximately 10 or 11 orbits or transits of the planet to make the water-vapor detection. Pierre-Alexis’ spectrum made it into our paper as one of our trend-data points, and we included all the planets from their proposal and others studied in the literature, making our results stronger. We were in close communication with them during the process of both papers to ensure we were using the proper updated results and accurately reflecting their findings.”

The patients from New Zealand, the Netherlands and the UK have hereditary angioedema, a genetic disorder characterised by severe, painful and unpredictable swelling attacks. These interfere with daily life and can affect airways and prove fatal.

Now researchers from the University of Auckland, Amsterdam University Medical Center and Cambridge University Hospitals have successfully treated more than ten patients with the CRISPR/Cas9 therapy, with interim results just published in a leading journal.

“It looks as if the single-dose treatment will provide a permanent cure for my hereditary angioedema patients’ very disabling symptoms,” says principal investigator Dr Hilary Longhurst, who is both a clinical immunologist at Auckland Hospital Te Toku Tumai and an honorary associate professor at the University of Auckland.

“Plus, of course, there is huge potential for development of similar CRISPR/Cas9 treatments for other genetic disorders.”

Globally, it is estimated one in 50,000 people have hereditary angioedema, however, because it is rare, it is often not correctly diagnosed.

In the phase one study, there were no serious or lasting side-effects from the single infusion, which took place over two to four hours under clinical supervision from late 2021 and onwards.

The investigational therapy, called NTLA-2002, utilises in vivo CRISPR/Cas9 technology to target the KLKB1 gene, which is responsible for producing plasma prekallikrein.

By editing this gene, the therapy reduces the levels of total plasma kallikrein, effectively preventing angioedema (swelling) attacks.

The trial, published in the New England Journal of Medicine, demonstrated dose-dependent reduction in total plasma kallikrein protein with reductions of up to 95 percent achieved.

A mean reduction of 95 percent in angioedema attacks was observed across all patients through to the latest follow-up.

The patients from the initial study will be followed up for a further 15 years to continue to assess long-term safety and efficacy.

A larger and more robust, double-blinded, placebo-controlled phase two trial is under way and a Phase 3 trial is planned to start in the second half of 2024.

Dr Danny Cohn, from the Department of Vascular Medicine at the Amsterdam University Medical Center says these promising results are a step forward for this group of patients.

“We’ve never been closer to the ultimate treatment goal of normalising hereditary angioedema patients’ lives and offering total control of the disease,” says Dr Cohn.

Dr Padmalal Gurugama, consultant in clinical immunology and allergy at Cambridge University Hospitals, UK says the gene editing therapy has the potential to significantly improve patients’ lives.

“Hereditary angioedema can cause patients severe swellings and intense pain which can be life-threatening as well as restricting normal activities, such as going to work or school.

“Because it is often misdiagnosed, many patients undergo unnecessary treatments and invasive procedures.”

The therapy affects only the patient and is not passed onto their children, who still have an even chance of inheriting the disorder.

The studies have been funded by US company Intellia Therapeutics, which chose New Zealand to lead the research as, at that time — late 2021, it had relatively fewer Covid-19 cases than other countries.

So far, the only approved CRISPR therapy, CASGEVY, is for sickle cell disease and beta thalassemia. However, CASGEVY is an ex vivo CRISPR therapy, where the cells are taken from the patient and edited outside of the body and then reinfused, whereas NTLA-2002 is an in vivo CRISPR therapy, where the targeted gene editing occurs directly within the body.

CRISPR technologies are being used to develop treatment for a wide range of diseases, such as genetic disease, cardiovascular disease, cancer and autoimmune diseases.

Findings from the study published in Nature Ecology & Evolution show tree seedlings planted next to the decoy smell solution were 20 times less likely to be eaten by animals.

“This is equivalent to the seedlings being surrounded by actual plants that are unpalatable to the herbivore. In most cases it does trick the animals into leaving the plants alone,” said PhD student Patrick Finnerty, the study’s lead author from the School of Life and Environmental Sciences Behavioural Ecology and Conservation Lab.

“Herbivores cause significant damage to valuable plants in ecological and economically sensitive areas worldwide, but killing the animals to protect the plants can be unethical,” he said.

“So, we created artificial odours that mimicked the smell of plant species they naturally avoid, and this gently nudged problematic herbivores away from areas we didn’t want them to be.

“Given that many herbivores use plant odour as their primary sense to forage, this method provides a new approach that could be used to help protect valued plants globally, either in conservation work or protecting agricultural crops.”

The experiment, conducted in Ku-ring-gai Chase National Park in Sydney, used the swamp wallaby as model herbivore. The researchers selected an unpalatable shrub in the citrus family, Boronia pinnata, and a palatable canopy species, Eucalyptus punctata, to test the concept.

The study compared using B. pinnata solution and the real plant and found both were equally successful at protecting eucalyptseedlings from being eaten by wallabies.

As part of his doctoral research, Mr Finnerty has also tested the method successfully with African elephants, but that fieldwork does not form part of this research paper.

Previous attempts to use repellent substances, such as chilli oil or motor oil, to control animal consumption of plants have inherent limitations, Mr Finnerty said.

“Animals tend to habituate to these unnatural cues and so deterrent effects are only temporary,” he said. “By contrast, by mimicking the smell of plants herbivore naturally encounter, and avoid in day-to-day foraging, our approach works with the natural motivators of these animals, with herbivores less likely to habituate to these smells.”

Researchers took this idea and used solutions that produce these undesired aromas.

“As a management tool to protect palatable plants, our technique offers many advantages over real plants as a repellent,” Mr Finnerty said. “Real plants compete for water and resources, which can outweigh protective effects in providing browsing refuge.

“Our approach should be transferable to any mammalian, or potentially invertebrate, herbivore that relies primarily on plant odour information to forage and could protect valued plants globally, such as threatened species.”

Current solutions to herbivore-related problems often involve costly and environmentally impactful measures such as lethal control or fencing.

The new research introduces an alternative low-cost, humane strategy based on understanding herbivores’ foraging cues, motivations and decisions.

“Plant browsing damage caused by mammalian herbivore populations like deer, elephants and wallabies is a growing global concern,” said senior study author Professor Clare McArthur.

“This damage is one of the greatest limiting factors in areas of post-fire recovery and revegetation, destroying more than half the seedlings in these areas. It also threatens endangered plants and causes billions of dollars of damage in forestry and agriculture globally.

“Current methods to protect plants are expensive and increasingly limited by concerns over animal welfare, so alternate approaches are needed.”