Tinkering with the “clockwork” mechanisms of life

University of Montreal

Living organisms monitor time – and react to it – in many different ways, from detecting light and sound in microseconds to responding physiologically in pre-programmed ways, via their daily sleep cycle, monthly menstrual cycle, or to changes in the seasons.

Such ability to react at different timescales is made possible via molecular switches or nanomachines that act or communicate as precise molecular timers, programmed to turn on and off in response to the environment and time.

Now, in new research, scientists at Université de Montréal have successfully recreated and validated two distinct mechanisms that can program both the activation and deactivation rates of nanomachines in living organisms across multiple timescales.

Their findings are published in the Journal of the American Chemical Society. Their breakthrough suggests how engineers can exploit natural processes to improve nanomedicine and other technologies, while also helping explain how life has evolved.

The door analogy
Biomolecular switches or nanomachines, typically made of proteins or nucleic acids, are the nuts and bolts of the machinery of life. They perform thousands of key functions, including chemical reactions, transporting molecules, stocking energy, and enabling movement and growth.

But how have these switches evolved to activate over different timescales? That’s a key question that has long fascinated chemists, and since the pioneering work by Monod-Wyman-Changeux and Koshland-Nemethy-Filmer in the 1960s two popular mechanisms are generally assumed to control the activation of biomolecular switches.

“The analogy of a door is convenient to illustrate these two mechanisms,” said UdeM chemistry professor Alexis Vallée-Bélisle, the principal investigator of the new study.

“The closed door represents the inactive structure of the switch or nanomachine while the open door represents its active structure. It is the interactions between the switch and its activating molecule, such as light or a molecule, that dictates the type of activation mechanism.”

“In the induced-fit mechanism, the activating molecule, or person, grabs the handle of the closed door, which provides the energy for fast opening,” Vallée-Bélisle explained. “In the conformational selection mechanism, the activating molecule needs to wait for the door to spontaneously open before it can interact and block this later in the open structure.”

While these two mechanisms were observed in many proteins, it is only recently that scientists have realized that these mechanisms could also be employed to engineer better nanosystems.

Using DNA to build a nanodoor
To unravel the mystery behind these two mechanisms and their functioning, researchers have successfully recreated a simple molecular “door” using DNA. Although DNA is mostly known for its ability to encode the genetic code of living organisms, several bioengineers have also started to use its simple chemistry to fabricate objects in nanoscale.

“Compared to protein, DNA is a highly programmable and versatile molecule,” said Dominic Lauzon, an associate researcher in chemistry at UdeM and co-author of the new study. “It’s like the Lego blocks of chemistry that allow us to build whatever we have in mind at the nanoscale.”

A thousand times faster
Using DNA, the UdeM scientists have created a 5-nanometre-wide “door” that can be activated via the two distinct mechanisms using the same activating molecule. This allowed the researchers to compare both switching mechanisms directly on the same basis, testing their design principles and ability to program.
They found that the “door handle” (induced-fit) switch activates and deactivates a thousand times faster because the activating molecule provides the energy to accelerate door opening. By contrast, the much slower switch with no handle (conformational selection) can be programmed to open at much slower rates by simply increasing the strength of the interactions maintaining the door closed.

“We have found that we can in fact program switches rates activation from hours to seconds simply by designing molecular handles” explained first author Carl Prévost-Tremblay a graduate biochemistry student.

“We also thought that this ability to program the rate of activation of switches and nanomachines could find many applications in nanotechnology where chemical events need to be programmed at specific times.”

Towards new drug-delivery tech
One field that would drastically benefit from developing nanosystems that activate and deactivate at different rates is nanomedicine, which aims to develop drug-delivery systems with programmable drug-release rates.

This would help to minimize how often a patient takes a drug and help maintain the right concentration of the drug in the body for the length of a treatment.

To showcase the high programmability of both mechanisms, the researchers designed and tested an antimalarial drug carrier that can release its drug at any programmed rate.

“By engineering a molecular handle, we developed a carrier that allows for fast and immediate release of the drug via the simple addition of an activating molecule,” said biomedical engineering master’s student Achille Vigneault, also author of the study. “And in the absence of a handle, we also developed a carrier that provides a programmable slow continuous release of the drug following its activation.”

These results also demystify the distinct evolutionary roles and advantages of the two signaling mechanisms, and explain why some proteins have evolved to be activated via one mechanism over the other, the scientists said.

“For example, cell receptors that require rapid activation to detect light or sense odors likely benefit from a fast induced-fit mechanism,” said Vallée-Bélisle, “while processes lasting for weeks, such as protease inhibition, definitively benefit from the slower conformational selection mechanism.”

About this study

“Programming the kinetics of chemical communication: induced fit vs conformational selection," by Carl Prévost-Tremblay, Achille Vigneault, Dominic Lauzon and Alexis Vallée-Bélisle, was published December 19, 2024 in the Journal of the American Chemical Society. Funding was provided by the National Sciences and Engineering Research Council of Canada, the Canada Research Chairs program, Les Fonds de recherche du Québec – Nature et technologies, and the PROTEO network.

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Journal

Journal of the American Chemical Society

DOI

10.1021/jacs.4c08597 

Article Title

Programming the kinetics of chemical communication: induced fit vs conformational selection

Article Publication Date

19-Dec-2024

FOSSILS

A festive flying reptile family reunion 150 million years in the making

University of Leicester study finds nearly 50 hidden relatives of Pterodactylus, the first pterosaur

University of Leicester

 

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Growth stages of Pterodactylus. From tiny ‘flaplings’ no larger than a sparrow, most known specimens represent ‘teenagers’ comparable in size to a pigeon. Fully grown individuals boasted impressive wingspans exceeding 1 metre. Unlike birds, which must grow before achieving flight, even the smallest Pterodactylus were capable of flight from an early age.

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Credit: University of Leicester

Christmas is the time for families to come together, and in the midst of the festive season University of Leicester paleontologists have announced that they have reunited a family that have been separated for 150 million years.

A new study published this week has found nearly 50 ‘hidden’ relatives of Pterodactylus, the first pterosaur, that will allow scientists to reconstruct this flying reptile’s life history from hatchling to adulthood.

Nearly 250 years ago, the very first pterosaur fossil was found in a quarry in northern Bavaria. Dubbed Pterodactylus, this 150-million-year-old fossil provided the first evidence for an extraordinary group of flying reptiles that filled the skies of the Mesozoic, soaring over the heads of dinosaurs on wings that could span up to 10 metres or more. While this first pterosaur was only the size of a turtle dove, it completely reshaped our understanding of prehistoric life.

Despite being the original ‘pterodactyl’, Pterodactylus was soon quite literally overshadowed in the public consciousness by more dramatic, giant pterosaurs like Pteranodon and Quetzalcoatlus, which stole the spotlight. But Pterodactylus remained a favourite among pterosaur scientists.

Over the centuries, Pterodactylus and other similar pterosaurs from Bavaria have been central to ongoing scientific study, helping shape much of what we know about pterosaurs, from the shape of their wings and how they flew, to their diet and how they grew. But one question has always lingered: which of these many pterosaurs are truly Pterodactylus and which belong to completely different species? This confusion has persisted for centuries... until now. Thanks to a new study that analysed dozens of specimens of Pterodactylus in museums around the world, the mystery has been solved, and the true identity of these fossils has finally been uncovered.

Shining powerful UV torches on fossil bones to make them fluoresce, University of Leicester paleontologists Robert Smyth and Dr Dave Unwin were able to bring to light tiny near-invisible bony details that distinguish one kind of pterosaur from another. Using Pterodactylus’ unique features, found in the head, hips, hands and feet, Smyth and Unwin systematically checked other fossils from the same deposits and to their surprise discovered many other examples of Pterodactylus ‘hiding’ in among what were thought to be other species of pterosaur.

Lead author Robert Smyth, a doctoral researcher in the in the Centre for Palaeobiology and Biosphere Evolution (School of Geography, Geology and the Environment at the University of Leicester), explained: "By examining lots of fossils in collections across Europe we were able to reidentify more than forty specimens as Pterodactylus. UV stimulated fluorescence is astonishing in the amount of detail it can reveal. Features that were once hidden were glowing in plain sight.” 

In an eyeblink the entire concept of Pterodactylus changed dramatically. With nearly 50 examples recognised so far, our knowledge of this most important of pterosaur has exploded. As co-author Dr David Unwin from the University of Leicester explained: “We can now construct a complete and highly detailed skeletal anatomy for this key pterosaur. Soft tissues are fossilised in more than twenty examples so we can also reconstruct head crests, body shape, foot webs and even the wings.”

The result? A sprawling family portrait of Pterodactylus, providing a unique opportunity to reconstruct its full life history. This spans from robin-sized hatchlings (affectionately dubbed ’flaplings’) to ’teenage’ Pterodactylus, all the way to raven-sized adults with wingspans nearly ten times larger.

Dr Unwin added: “UV stimulated fluorescence is a well-known technique, but the difference in this case is that we have been able to combine new high quality light sources with a systematic ‘catch-all’ approach, and it's going to have a revolutionary impact on our understanding of pterosaurs.”   

Ends

UV photography of Pterodactylus. Ultraviolet light reveals remarkable details of the fossil invisible under normal lighting. This famous specimen showcases preserved soft tissues, including the delicate wing membranes, which fluoresce vividly under UV illumination.UV photography of Pterodactylus. Ultraviolet light reveals remarkable details of the fossil invisible under normal lighting. This famous specimen showcases preserved soft tissues, including the delicate wing membranes, which fluoresce vividly under UV illumination.

Family resemblance. This larger specimen is slightly jumbled, but it still reveals many important details, including the anatomy of the hands and feet, which have been found to be highly diagnostic features. This allows us to distinguish Pterodactylus from other closely related pterosaurs.

Credit

University of Leicester

About the University of Leicester  

The University of Leicester is the Daily Mail University of the Year 2025 and shortlisted for University of the Year for both the Times Higher Education Awards 2024 and the Times and Sunday Times Good University Guide 2025.

The University is led by discovery and innovation – an international centre for excellence renowned for research, teaching and broadening access to higher education. It is among the Top 30 universities in the Times Higher Education (THE)’s Research Excellence Framework (REF) 2021 rankings with 89% of research assessed as world-leading or internationally excellent, with wide-ranging impacts on society, health, culture, and the environment. In 2023, the University received an overall Gold in the Teaching Excellence Framework (TEF) 2023, making it one of a small number of institutions nationally to achieve TEF Gold alongside a top 30 REF performance. The University is home to more than 20,000 students and approximately 4,000 staff.

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Journal

Journal of Systematic Palaeontology

DOI

10.1080/14772019.2024.2421845 

Article Title

Re-evaluation of Pterodactylus antiquus and Diopecephalus kochi: two troublesome taxonomic concepts

Article Publication Date

17-Dec-2024

La Brea Tar Pits Researchers identify a mysterious fossil seed to reveal new chapters in LA’s climate history

La Brea Tar Pits scientists successfully identify a previously unknown species to Southern California from fossilized seeds, revealing a drought-fueled dance between two species of juniper with lessons for the region’s climate future

Natural History Museum of Los Angeles County

 

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Fluorescent and scanning electron microscopy (SEM) of fossil and modern juniper leaves. (a, b) Fluorescent microscope imagery of fossil juniper branchlet (LACMHC 1469B). (b) Close-up of leaf scale with smooth leaf margins and acute-slightly obtuse apical shape. (c) SEM image of entire fossil leaf scale from adaxial (dorsal) perspective. (d–g) Close-up imagery of abaxial (ventral) side of modern (d) J. blancoi, (e) J. scopulorum, (f) J. virginiana, and (g) fossil juniper leaf (P23-47594).

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Credit: J. George et al. SEM Imagery by Giar-Ann Kung

Los Angeles (December 19, 2024)—La Brea Tar Pits scientists have identified a previously unknown juniper species to the La Brea Tar Pits as Juniperus scopulorum, commonly known as the Rocky Mountain juniper. The successful identification, along with the first-ever radiocarbon dating of these fossil plants in Southern California, expands our ability to track past environmental changes and highlights the vulnerability of junipers and the environments they shape in the face of modern climate change. Published in the journal New Phytologist, the study unlocks a key finding to understanding the megafaunal extinction at the Tar Pits and better understanding our own climate future. 

The mammoths and saber-toothed cats that shape our imagination of Ice Age Los Angeles browsed, grazed, and hunted in juniper woodlands. More than just a source of food for giant herbivores, junipers were keystone trees and shrubs in the region, in turn shaping the landscape for at least 47,000 years before completely vanishing from the region in the same extinction event that erased most of the megafauna. 

Researchers have long known that there are two different species of juniper found at the Tar Pits—the large-seeded J. californica (California juniper), and the small-seeded, mystery juniper. With distinct tolerances for temperature and drought, fossil junipers play a crucial role in understanding the changing climate of the last Ice Age, and how junipers can survive our climate future, but the identity of the mystery seed remained uncertain—until now. 

“We set out to identify this mystery juniper, and in the process, we found a number of exciting things,” says Dr. Jessie George, postdoctoral researcher at La Brea Tar Pits, and lead author on the study.  “Number one, we identified this juniper as Rocky Mountain juniper, and it is one of the most extreme examples of a plant going extinct locally. It’s not present anywhere in California today.”

As part of the study, George and the other Tar Pits researchers radiocarbon dated the two species of juniper, which led to the second exciting finding: “In the process of radiocarbon dating these juniper species, we found this really interesting pattern of reciprocal presence—either California juniper only or Rocky Mountain juniper only.”

Because each plant survives in specific conditions, its presence acts as a proxy for climate. George and her colleagues found that this dance between the two junipers coincided with long periods of drought and warm, dry weather that would otherwise be hidden in the fossil record. “California juniper is a much more drought tolerant species. It withstands moisture deficit way better than Rocky Mountain juniper,” says George. “Through these back-and-forth occurrences of the two species from the Tar Pits, we have this really fascinating record of aridity and drought that was previously undetected.”

The small size of the unknown juniper seed—about as big as Lincoln’s forehead on a penny—made it a difficult subject, especially since DNA has yet to be extracted from Tar Pits fossils. Instead, George compared the structure of seeds and branchlets to other juniper species—the only way to uncover its identity. It required careful comparison using advanced microscopy, image analysis, and species distribution modeling (SDM) until the team reached a definitive answer. 

While climate definitely played an important role in their local extinction, the team thinks that the abrupt disappearance of Ice Age megafauna and fires started by humans may have also contributed, much like in the case of those iconic giant mammals. In a hotter, drier climate, even plants well-adapted to drought couldn’t survive the extra stress of human fires. This is especially true for plants that are not adapted to wildfire–unlike many other conifer species, juniper has little tolerance for surviving or re-growing following fires. The finding highlights the threat junipers continue to face from human-caused climate change and could inform conservation efforts going forward. 

“We're seeing events of really dramatic decline of these trees in the southwest today because of warming temperatures and increased wildfire caused by modern climate change. So a direct record of how this might have occurred in the past, what factors were at play, and where those boundaries occurred is incredibly important,” says George. “It gives us a better framework to understand a baseline of climate and environment to contextualize changes in other plant life and the fauna that we see during these periods of significant change in the past. As our ability to precisely date fossils improves, better and more detailed information is revealed from ancient life at La Brea.”

Identification of fossil juniper seeds from Rancho La Brea (California, USA): drought and extirpation in the Late Pleistocene was authored by Jessie George, Monica Dimson, Regan E. Dunn, Emily L. Lindsey, Aisling B. Farrell, Brenda Paola Aguilar, Glen M. MacDonald and was published in New Phytologist on December 10, 2024
 

About La Brea Tar Pits 
The asphalt seeps at La Brea Tar Pits are the only consistently active and urban Ice Age excavation site in the world. This makes the site a unique window into active science—where fossils are discovered, prepared, researched, and displayed in one place. Outside, visitors can watch excavators unearth fossils of Ice Age plants and animals that were trapped and preserved in the seeps. Inside the museum, scientists and volunteers clean, repair, and identify those fossils. The best specimens are displayed and available for research: from extraordinary saber-toothed cats, giant sloths, dire wolves, mammoths, and mastodons—to microfossils of small animals and plants. These collections constitute an unparalleled resource for understanding environmental change in Los Angeles, and the planet, during the last 50,000 years of Earth’s history.

About the Natural History Museums of Los Angeles County 
The Natural History Museums of Los Angeles County (NHMLAC) include the Natural History Museum in Exposition Park, La Brea Tar Pits in Hancock Park, and the William S. Hart Museum in Newhall. They operate under the collective vision to inspire wonder, discovery, and responsibility for our natural and cultural worlds. The museums hold one of the world’s most extensive and valuable collections of natural and cultural history—more than 35 million objects. Using these collections for groundbreaking scientific and historical research, the museums also incorporate them into on- and offsite nature and culture exploration in L.A. neighborhoods, and a slate of community science programs—creating indoor-outdoor visitor experiences that explore the past, present, and future. Visit NHMLAC.ORG for adventure, education, and entertainment opportunities.

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Journal

New Phytologist

DOI

10.1111/nph.20324 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Identification of fossil juniper seeds from Rancho La Brea (California, USA): drought and extirpation in the Late Pleistocene

 

Chungnam National University researchers develop a rapid water quality monitoring chip for antibiotic detection

New microfluidic electrochemical sensor containing selenite-enriched lanthanum hydroxide enables on-site detection of trimethoprim molecules

Chungnam National University Evaluation Team

 

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Scientists developed a simple TMP detection device for on-site monitoring of contaminated wastewater using selenite-enriched lanthanum hydroxide electrode and polyimide-filter microfluidic channel.

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Credit: Tae Yoon Lee from Chungnam National University, Korea

Antimicrobial resistance (AMR) is a growing global health crisis because of microbes, such as bacteria, becoming resistant to antibiotics. A leading factor in this rise is the improper use and disposal of antibiotics in the environment. Effluents from wastewater treatment plants often contain various antibiotics including trimethoprim (TMP), which can harm ecosystems by disrupting microbial communities essential for nutrient cycling. In addition to contributing to AMR, TMP poses various health risks to humans through indirect exposure.

Traditional methods for TMP detection such as capillary electrophoresis and liquid chromatography with mass spectrometry, are often labor-intensive and time-consuming. Electrochemical (EC) methods can provide respite from these issues by offering exceptional sensitivity, real-time analytical capabilities and the potential for miniaturization.

Professor Tae Yoon Lee and Dr. Natarajan Karikalan of Chungnam National University, Korea, have made a pioneering advancement in EC detection methods, that shows promise to revolutionize on-site testing for TMP in contaminated wastewater. They developed a disposable microfluidic lab-on-a-chip (LOC) EC sensor, μTMP-chip, designed for real-time TMP detection. “Efficient TMP monitoring in effluents is critical for effective control protocols. Hence, we aimed to enable in situ testing of water samples,” explains Prof. Lee. Their paper was made available online on September 21, 2024 and was published in Volume 499 of Chemical Engineering Journal on November 1, 2024.

The researchers designed the disposable chip by combining a special electrode made with lanthanum hydroxide and selenite, with a polyimide (PI) filter in a microfluidic channel. The analyses showed that the addition of selenite improved the electrode’s ability to detect chemicals by allowing better charge flow. Additionally, the PI filter improved the μTMP-chip’s real-time performance, while the efficiency dropped by 15 to 45% when the filter was removed. Additionally, the filter helped trap and isolate unwanted materials and prevented the risk of microbial growth, which could interfere with the sensor's function.

The μTMP-chip sensor demonstrated impressive results in real-world testing, showing recovery rates of 94.3 % to 97.6 % in soil and water samples. These results, obtained through wireless testing, highlight the chip’s potential for practical use in monitoring environmental samples.

“Our current design may face challenges in detecting TMP in highly polluted environments with significant matrix interferences. However, we hope our research will inspire further exploration into developing affordable and efficient TMP detection chips,” said Prof. Lee.

The researchers believe that their innovative lab-on-a-chip design has the potential to improve the feasibility of on-site, real-time tracking of environmental contaminants leading to improved conservation of ecosystems and human health.

 

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Reference

Title of original paper: Microfluidic sensor integrated with selenite-enriched lanthanum hydroxide and in situ filtration for the on-site detection of the antibiotic trimethoprim in environmental samples

Journal: Chemical Engineering Journal

DOI: https://doi.org/10.1016/j.cej.2024.155982

 

About the institute

Chungnam National University (CNU), located in Daejeon, South Korea, is a leading national university renowned for its excellence in research and education. Established in 1952, CNU offers diverse programs in engineering, medicine, sciences, and the arts, fostering innovation and global collaboration. Situated near Daedeok Innopolis, a major R&D hub, it excels in biotechnology, materials science, and information technology. With a vibrant international community and cutting-edge facilities, CNU continues to drive academic and technological advancements, making it a top choice for students worldwide.

Website: https://plus.cnu.ac.kr/html/en/

 

About the author

Dr. Tae Yoon Lee is a Professor at Chungnam National University, serving in the Departments of Convergence System Engineering. His primary research interest lies in microfluidics, where he has made significant contributions. Dr. Lee has published over 46 research articles, garnering nearly 900 citations with an impressive h-index of 19, underscoring his impact in the field.

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Journal

Chemical Engineering Journal

DOI

10.1016/j.cej.2024.155982 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Microfluidic sensor integrated with selenite-enriched lanthanum hydroxide and in situ filtration for the on-site detection of the antibiotic trimethoprim in environmental samples

First-of-its-kind study uses remote sensing to monitor plastic debris in rivers and lakes

Remote sensing creates a cost-effective solution to monitoring plastic pollution

University of Minnesota

 

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A new study looks at how remote sensing could help monitor and remove plastic debris from freshwater lakes and rivers.

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Credit: Mohammadali Olyaei, University of Minnesota Twin Cities

MINNEAPOLIS / ST. PAUL (12/19/2024) — A first-of-its-kind study from researchers at the University of Minnesota Twin Cities shows how remote sensing can help monitor and remove plastic debris from freshwater environments like the Mississippi River.

The research, published in Nature, a peer-reviewed scientific journal, helps to increase the understanding of plastic debris behavior in freshwater environments.

Plastic pollution in oceans continues to be a growing environmental issue, with the United Nations Environment Programme naming it one of the leading pollution challenges. But, plastic pollution in lakes and rivers, or freshwater environments, has garnered less attention.

That is something the researchers wanted to change, because much of the plastic debris in oceans makes its way there through rivers. Previous studies in removing plastic waste use labor-intensive sampling, which can be time-consuming and expensive.

To help with those challenges, this study used remote sensing technology that can provide cost-effective solutions and reach a wider area. The technology uses spectral reflectance properties, or wavelengths in the electromagnetic spectrum, to pinpoint specific types of plastic. It’s important to find the specific wavelength of the plastic materials, so that the sensing technology can filter out materials found naturally in freshwater environments, such as seaweed, sediments, driftwood, and water foams.

“We could use this technology to identify different types of plastics in the water simultaneously. This is key information that we need when employing other technology, like drones, to capture and remove plastic debris in natural environments,” said Mohammadali Olyaei, a Ph.D. student in the Department of Civil, Environmental, and Geo- Engineering and lead author on the paper.

Conducting their research at the St. Anthony Falls Laboratory allowed the researchers to use actual conditions of the Mississippi River to test their theory since the river runs through the laboratory space. The researchers used a combination of a remote sending platform (spectroradiometer) and a digital single-lens reflex (DSLR) camera to monitor and classify various types of debris, based on their spectral signatures, which can aid in effectively removing plastic debris. 

“If we can develop technology at the Mississippi headwaters, in a place like Minnesota, to catch plastic debris, we can protect the downstream states and the entire ocean from plastic pollution. As soon as these plastics begin to spread more and more, their control becomes more and more challenging,” said Ardeshir Ebtehaj, Associate Professor in the Department of Civil, Environmental, and Geo- Engineering and corresponding author of the study. 

The researchers hope to continue this on a larger scale to increase their understanding of where this plastic debris comes from, how it moves across river systems, and how they can remove it.

In addition to Olyaei and Ebtehaj, the team included Christopher R. Ellis, a senior research associate at the St. Anthony Falls Laboratory.

This work was funded by the Minnesota Environment and Natural Resources Trust Fund (ENTRF) as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). The ENRTF is a permanent fund in Minnesota that provides funding for the protection and conservation of Minnesota's natural resources. 

Read the entire research paper titled, “A Hyperspectral Reflectance Database of Plastic Debris with Different Fractional Abundance in River Systems,” visit Nature’s website.

Monitoring Plastic Pollution [VIDEO] | 

A first-of-its-kind study from researchers at the University of Minnesota Twin Cities shows how remote sensing can help monitor and remove plastic debris from freshwater environments like the Mississippi River.

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Journal

Scientific Data

DOI

10.1038/s41597-024-03974-x 

Article Title

A Hyperspectral Reflectance Database of Plastic Debris with Different Fractional Abundance in River Systems

An inexpensive fix for California’s struggling wildflowers

Rake dead grass to increase flower power

University of California - Riverside

 

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UC Riverside students sampling plants for this study in encouraging biodiversity.

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Credit: Advyth Ramachandran/UCR

California’s native wildflowers are being smothered by layers of dead, invasive grasses. A new UC Riverside study shows that simply raking these layers can boost biodiversity and reduce fire danger.

The study, published this week in Restoration Ecology, tested whether removing thatch — dead leaves and debris — could allow native seeds to germinate and grow. Compared to other techniques for managing invasive grasses, such as controlled burns, hand weeding, and spraying herbicides, raking is decidedly less labor intensive and more ecologically friendly.

“In these ecosystems, native seeds often fall on thick layers of thatch and can’t germinate. Raking the thatch lets light in and gives native plants a chance to grow,” said Marko Spasojevic, study author and UCR associate professor of plant ecology.

In grasslands near the UCR campus, researchers used a grid of paired plots — one raked and one untouched — to measure plant community changes over the course of three years. Results showed raking increased plant diversity overall, reducing invasive grasses like ripgut brome while increasing both native and exotic wildflowers, known as forbs.

Ripgut brome, a dominant invasive grass, earned its name from its sharp, bristly hairs, which can injure grazing animals. “It’s super nasty for sheep and cattle to eat,” Spasojevic said. Meanwhile, native flowers like the common fiddleneck, prevalent in Riverside, benefited modestly from raking.

While raking reduced invasive grasses, there was a trade-off. It also increased certain exotic wildflowers, such as mustard, which can be highly invasive.

“Raking boosted native wildflowers by about 5% and exotic forbs by 7 to 10%,” said Advyth Ramachandran, who co-led the project as a UCR undergraduate and now studies plant ecology at the University of Colorado Boulder. “This doesn’t mean raking isn’t worthwhile. It’s a simple, low-cost method that could be a first step for restoring these systems.”

The roots of this project stretch back decades. The study plots were originally created for an introductory biology class in the 1980s and were later abandoned. During the pandemic, Ramachandran and other UCR students revived the site, launching a grassroots research initiative through the university’s SEEDS club.

“We built this project from scratch, writing protocols, identifying species, and involving over 25 undergraduates,” Ramachandran said. “It’s rare for undergraduates to initiate and lead publishable research like this.”

Spasojevic credits the project’s success to its accessibility. “The research site is on campus, so students could sample between classes. It lowered barriers for involvement and became a rich mentorship opportunity,” he said. The SEEDS initiative remains active, with students continuing to collect data for a fifth consecutive year.

The team’s findings have practical implications for land managers seeking low-cost methods to restore native plant diversity in grasslands and coastal sage ecosystems.

Native plants provide food and habitat for local wildlife, support pollinators like bees, and reduce soil erosion. Invasive grasses, on the other hand, not only outcompete native species but also increase wildfire risk with their dense, flammable layers. Boosting native wildflowers is key to restoring and maintaining healthy ecosystems.

“This project shows how small actions—like raking—can make meaningful differences in our ecosystems,” Ramachandran said. “It’s a promising step toward restoring California’s native landscapes.”

Wildflower competing with invasive grasses on a hillside near UC Riverside. 

Credit

Advyth Ramachandran/UCR

UCR students raking experimental study plots. 

Credit

Advyth Ramachandran/UCR

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Journal

Restoration Ecology

DOI

10.1111/rec.14340 

Article Title

Litter removal increases plant diversity by promoting both native and exotic forbs in heavily invaded coastal sage scrub in Southern California, U.S.A.

Article Publication Date

16-Dec-2024