A team led by Rafael Auras has made a bio-based polymer blend that’s compostable in both home and industrial settings. The work is published in the journal ACS Sustainable Chemistry & Engineering.

“In the U.S. and globally, there is a large issue with waste and especially plastic waste,” said Auras, MSU professor and the Amcor Endowed Chair in Packaging Sustainability.

Less than 10% of plastic waste is recycled in the U.S. That means the bulk of plastic waste ends up as trash or litter, creating economic, environmental and even health concerns.

“By developing biodegradable and compostable products, we can divert some of that waste,” Auras said. “We can reduce the amount that goes into a landfill.”

Another bonus is that plastics destined for the compost bin wouldn’t need to be cleaned of food contaminants, which is a major obstacle for efficient plastic recycling. Recycling facilities routinely must choose between spending time, water and energy to clean dirty plastic waste or simply throwing it out.

“Imagine you had a coffee cup or a microwave tray with tomato sauce,” Auras said. “You wouldn’t need to rinse or wash those, you could just compost.”

PLA and a ‘sweet spot’ for starch

The team worked with what’s known as polylactic acid, or PLA, which seems like an obvious choice in many ways. It’s been used in packaging for over a decade, and it’s derived from plant sugars rather than petroleum.

When managed properly, PLA’s waste byproducts are all natural: water, carbon dioxide and lactic acid.

Plus, researchers know that PLA can biodegrade in industrial composters. These composters create conditions, such as higher temperatures, that are more conducive to breaking down bioplastics than home composters.

Yet, the idea of making PLA compostable at home seemed impossible to some people.

“I remember people laughing at the idea of developing PLA home composting as an option,” said Pooja Mayekar, a doctoral student in Auras’ lab group and the first author of the new report. “That’s because microbes can’t attack and consume PLA normally. It has to be broken down to a point where they can utilize it as food.”

Although industrial compost settings can get PLA to that point, that doesn’t mean they do it quickly or entirely.

“In fact, many industrial composters still shy away from accepting bioplastics like PLA,” Auras said.

In its experiments, supported by the U.S. Department of Agriculture and MSU AgBioResearch, the team showed that PLA can sit around for 20 days before microbes start digesting it in industrial composting conditions.

To get rid of that lag time and enable the possibility of home composting, Auras and his team integrated a carbohydrate-derived material called thermoplastic starch into PLA. Among other benefits, the starch gives composting’s microbes something they can more easily chow down on while the PLA degrades.

“When we talk about the addition of starch, that doesn’t mean we just keep dumping starch in the PLA matrix,” Mayekar said. “This was about trying to find a sweet spot with starch, so the PLA degrades better without compromising its other properties.”

Fortunately, postdoctoral researcher Anibal Bher had already been formulating different PLA-thermoplastic starch blends to observe how they preserved the strength, clarity and other desirable features of regular PLA films.

Working with doctoral student Wanwarang Limsukon, Bher and Mayekar could observe how those different films broke down throughout the composting process when carried out at different conditions.

“Different materials have different ways of undergoing hydrolysis at the beginning of the process and biodegrading at the end,” Limsukon said. “We’re working on tracking the entire pathway.”

The team ran these experiments using systems that Auras and lab members, past and present, largely built from scratch during his 19 years with MSU. The equipment the researchers have access to outside their own lab in the School of Packaging also makes a difference.

“Working with Dr. Auras, the School of Packaging, MSU — it’s great,” Bher said. “Because, at some point, we want to be making actual products. We are using facilities around campus to make materials and test their properties. MSU offers a lot of resources.”

“There’s a reason why this is one of the best schools for packaging,” Mayekar said.

The research team at The University of Texas at Austin created a noninvasive electroencephalogram (EEG) sensor that they installed in a Meta VR headset that can be worn comfortably for long periods. The EEG measures the brain’s electrical activity during the immersive VR interactions.

The device could be used in many ways, from helping people with anxiety, to measuring the attention or mental stress of aviators using a flight simulator, to giving a human the chance to see through the eyes of a robot.

“Virtual reality is so much more immersive than just doing something on a big screen,” said Nanshu Lu, a professor in the Cockrell School of Engineering’s Department of Aerospace Engineering and Engineering Mechanics who led the research. “It gives the user a more realistic experience, and our technology enables us to get better measurements of how the brain is reacting to that environment.”

The research is published in Soft Science.

The pairing of VR and EEG sensors has made its way into the commercial sphere already. However, the devices that exist today are costly, and the researchers say their electrodes are more comfortable for the user, extending the potential wearing time and opening up additional applications.

The best EEG devices today consist of a cap covered in electrodes, but that does not work well with the VR headset. And individual electrodes struggle to get a strong reading because our hair blocks them from connecting with the scalp. The most popular electrodes are rigid and comb-shaped, inserting through the hairs to connect with the skin, an uncomfortable experience for the user.

“All of these mainstream options have significant flaws that we tried to overcome with our system,” said Hongbian Li, a research associate in Lu’s lab.

For this project, the researchers created a spongy electrode made of soft, conductive materials that overcome those issues, an effort led by Li. The modified headset features electrodes across the top strap and forehead pad, a flexible circuit with conductive traces similar to Lu’s electronic tattoos, and an EEG recording device attached to the back of the headset.

This technology will play into another major research project at UT Austin: A new robot delivery network that will also serve as the largest study to date on human-robot interactions.

Lu is a part of that project, and the VR headsets will be used by people either traveling with robots or in a remote “observatory.” They will be able to watch along from the robot’s perspective, and the device will also measure the mental load of this observation for long periods.

“If you can see through the eyes of the robot, it paints a clearer picture of how people are reacting to it and lets operators monitor their safety in case of potential accidents,” said Luis Sentis, a professor in the Department of Aerospace Engineering and Engineering Mechanics who is co-leading the robot delivery project and is a co-author on the VR EEG paper.

To test the viability of the VR EEG headset, the researchers created a game. They worked with José del R. Millán, a faculty member in the Chandra Family Department of Electrical and Computer Engineering and the Dell Medical School and an expert in brain-machine interfaces, to develop a driving simulation that has the user press a button to react to turn commands.

The EEG measures the brain activity of the users as they make driving decisions. In this case, it shows how closely the subjects are paying attention.

The researchers have filed preliminary patent paperwork for the EEG, and they’re open to partner with VR companies to create a built-in version of the technology.

Other members of the research team include Hyonyoung Shin, Minsu Zhang, Nicholas Riveira and Susmita Gangopadahyay of the Chandra Family Department of Electrical and Computer Engineering; Andrew Yu, Heeyong Huh, Zhengjie Li, and Yifan Rao from the Department of Aerospace Engineering and Engineering Mechanics; Sangjun Kim from the Walker Department of Mechanical Engineering, Jessie Peng of the Department of Biomedical Engineering; and Gubeum Kwon of Artue Associates Inc. in South Korea.

New research shows just how complex and sophisticated these bacterial circadian clocks are, clearing the way for an exciting new phase of study. This work will provide diverse opportunities, from precision timing of the use of antibiotics, to bioengineering smarter gut and soil microbiomes.

An international collaboration from Ludwig Maximillian University Munich (LMU Munich), The John Innes Centre, The Technical University of Denmark, and Leiden University, made the discovery by probing gene expression as evidence of clock activity in the widespread soil bacterium Bacillus subtilis.

Lead author Dr. Francesca Sartor (LMU Munich) reports: “The circadian clock in this microbe is pervasive: we see it regulating several genes, and a range of different behaviours.”

Professor Antony Dodd from the John Innes Centre added, “It is astonishing that a unicellular organism with such a small genome has a circadian clock with some properties that evoke clocks in more complex organisms.”

Previous work by this collaborative team had demonstrated the existence of a circadian clock in a lab-derived strain of this bacteria. This was the first-time circadian clocks had been observed in the bacterium Bacillus subtilis. Researchers used a technique which inserts an enzyme called luciferase that produces light when a gene is expressed. This bioluminescence guided the team in monitoring the bacterial clock as conditions varied.

The senior author of the publication, Professor Martha Merrow at LMU Munich said: “This study shows that circadian clocks are widely found in Bacillus subtilis. We might capitalize on knowledge of the clock to improve health outcomes and increase sustainability of food production or biotechnology.”

This new study is a significant step forward for multiple reasons. It reveals that these clocks exist in strains collected from natural environments, so could be widespread in this bacteria. Furthermore, B. subtilis continues to show circadian rhythms in both constant dark and constant light, and the researchers reveal examples of nuanced responses found in the circadian clocks of many other organisms. In the field of circadian biology, these responses are known as “aftereffects” and “Aschoff’s Rule.” Taken together, this suggests that, as in more complex organisms, the bacteria can synchronize their physiology and metabolism to different times of the day as light and temperature conditions change.

The discovery offers opportunities for biotechnology, human health, and plant science. Understanding properties of bacterial circadian clocks may help us with industrial applications of microbiology; it could lead to a new understanding of how microbiomes are formed and may indicate how well antibiotics work at certain times of the day to disrupt pathogenic bacteria. The knowledge may also help us in crop protection. Bacillus subtilis is a beneficial soil bacterium used by farmers to assist nutrient exchange, plant development and defense against pathogenic microbes.

The team is developing Bacillus subtilis as a model organism for the study of circadian clocks in bacteria. One of the next steps is to work out which genes are operating to make up the clock mechanism. The team is also curious about how the B. subtilis circadian clock depends on multicellular organization for its full functionality.

Circadian clocks are internal oscillators which offer a selective advantage to organisms by adapting their physiology and metabolism to 24 h changes in the environment, such as the changes in light, temperature or predator behaviour. They give rise to the jarring effects of jet lag, when we pass into different time zones.

Professor Ákos T. Kovács, from Leiden University and Technical University of Denmark said, “The French biologist Jacques Monod once famously said, ‘What is true for E. coli is true for the elephant.’ At the time, he was referring to the universal rules of molecular biology- of DNA and proteins. Similarly, it is amazing that the circadian clock in Bacillus subtilis– a bacterium with just four thousand genes — has a complex circadian system that is reminiscent of circadian clocks in complex organisms such as flies, mammals, and plants.”

“The findings of this study are exciting, especially given much of the recent news regarding sargassum is about the negative effects of its overgrowth in Florida and the Caribbean,” said Lindsay Dubbs, a research associate professor and director of the Outer Banks Field Site at the UNC Institute for the Environment and research associate at East Carolina University’s Coastal Studies Institute. “We were able to show sargassum’s role in nitrogen fixation as meaningful in supporting marine productivity.”

Nitrogen is critical for life. Plants and animals need it for growth. More nitrogen in the ocean means greater biological productivity and growth. Sargassum mats provide an important habitat for organisms to perform nitrogen fixation, but few studies have measured it in sargassum communities.

“Only four studies have been published detailing rates of nitrogen fixation by epiphytes on pelagic sargassum and none in over 30 years,” said Claire Johnson, a Ph.D. student in the Department of Earth, Marine, and Environmental Sciences in the UNC College of Arts and Sciences and a graduate research assistant at the Coastal Studies Institute. “It’s really exciting for us to be able to contribute this long-term dataset which provides an updated view of this process and, in doing so, will hopefully bring attention to something which has been overlooked for decades.”

The team compared the nitrogen fixation rate with other marine sources, including commonly studied nitrogen fixing organisms such as planktonic diazotrophs and coastal epiphytes — plants that grow on other plants — and found the sargassum communities outpaced them — contributing significantly to the marine nitrogen cycle and potentially to sargassum blooms.

Collecting this type of data can be difficult, but the team’s proximity to the Gulf Stream from their lab at the Coastal Studies Institute on East Carolina University’s Outer Banks campus on Roanoke Island made it possible for them to make day-long trips to collect samples seasonally and process them quickly. The team was able to collect whole fronds of the seaweed and process them with minimal handling, better keeping the microorganisms intact for the study. Each piece was carefully managed in large tubs at the laboratory, where they collected data on nitrogen fixation rates. The team collected samples over a six-year period.

Sargassum is typically abundant in the Caribbean Sea, Gulf of Mexico, Gulf Stream and Sargasso Sea. The team’s work in North Carolina provides a comprehensive view of how nitrogen fixation rates vary over time, but understanding how they could vary across a wider geographic range could be a next step for further research.

“This research is even more critical now given the sargassum blooms in the South Atlantic,” said Johnson. “If nitrogen is being fixed by epiphytes on sargassum in this population on a scale anywhere near what we are seeing here, it would almost certainly have a significant impact on the Atlantic marine nitrogen budget.”

“There is so much to be learned about this plant, the other life that it supports, and the factors that contribute to it becoming a nuisance in some places. I am optimistic that our long-term dataset will continue to reveal new insights about its importance and complexity,” Dubbs added.

This organic matter, composed of decaying leaves and branches, airborne particulates and moisture, is called canopy soil or arboreal soil. Its study is relatively new, says Utah State University ecologist Jessica Murray. She’s among researchers unraveling mysteries of the dense, mossy humus that provides rich habitat for insects, birds, fungi, worms and plants, as well as a generous reservoir for carbon storage.

Murray and colleagues from Texas A&M University, the University of Toronto Scarborough and Imperial College London published new information about the enigmatic resource in the July 27, 2023, online edition of Geoderma. The team’s research was supported by USU, the U.S. Department of Agriculture National Institute of Food and Agriculture, and the Natural Sciences and Engineering Research Council of Canada.

“In this study, we sought to understand where canopy soils are found, where they are most abundant, and if their properties — and thus, soil development processes — differ as a function of climate or other small-scale factors,” says Murray, a doctoral student in USU’s Department of Biology and Ecology Center. “This is the first study to look at the distribution patterns of canopy soils across forests and one of very few studies that have sought to examine canopy soil properties.”

Murray collected much of the data for the study some 80 feet above the ground at six primary forest sites across Costa Rica’s Cordillera de Tilarán and Cordillera Volcánica Central, encompassing both Caribbean and Pacific slope mountain ranges. Her field gear includes climbing gear, ropes, a safety harness and helmet.

“I climbed about 30 trees to collect data,” she says. “And getting to one of those sites was the hardest hike of my life.”

Murray is referring to a site designated “Puesto 1070,” located along a contiguous tract of primary forest, which required a steep trek from about 1,970 feet in elevation to 3,608 — in thick mud.

“It took eight hours to complete the hike just to the study site,” she says. “We were carrying all of our climbing gear, food for eight days, sleeping bags and sampling equipment. Thank heavens we finished that site early, because, with our hard-earned appetites, we also nearly finished our food supply ahead of schedule.”

Murray says tree canopies in the tropical montane forest systems are especially dense, with thick moss, soil and an abundance of epiphytes — plants that grow on other plants — often referred to as “air plants” — that are not parasitic and have little or no attachment to other obvious nutrient sources.

“It’s like another world in the air — canopies teeming with plant, insect and animal life,” she says. “I initially conducted surveys to assess canopy soil abundance from the ground with binoculars. But it was really necessary to climb up into the trees to get an accurate picture of what was going on.”

Murray asserts forest canopies store much more carbon that generally assumed.

“It’s kind of a back-of-the-envelope calculation on my part, but one I’m ready to defend and eager to investigate further,” she says. “I think canopy soil stores 0.4 to 4 percent of total soil carbon in the forests where it is found, which is not being counted in ecosystem carbon budgets.”

Mentored by USU Biology Professor John Stark and former USU faculty member Bonnie Waring, the latter now with Imperial College London and an author on the paper, Murray says the team’s results indicate both climate and tree size play an important role in canopy soil abundance, carbon stocks and chemistry.

“Climate, particularly fog and temperature changes, appear to drive canopy soil abundance across forests, while tree size determines canopy soil abundance within a forest,” she says. “Our findings reveal canopy soil’s vulnerability to climate change, and its decline, could cause a significant decrease in carbon storage resources.”

Further, she says, those resources could take longer than expected to restore.

“When we talk about reforestation, we don’t stop to consider the time needed for forest regrowth plus canopy mat regrowth,” Murray says. “It may take decades longer for recovered forests destroyed by wildfire or development to regenerate robust canopy soil mats.”

A 2022 recipient of the Ecological Society of America’s Katherine S. McCarter Graduate Student Policy Award, Murray is among a number of Aggies presenting at the ESA’s 2023 Annual Meeting Aug. 6-11, in Portland, Oregon. She presents the talk, “The Persistence of Metabolically Protected vs. Mineral-Associated Soil Organic Carbon in the Presence of Organic Inputs,” on Thursday, Aug. 10 at the Oregon Convention Center.

“For that meeting, I’ll be presenting on research different from, but related to, the study published in Geoderma, including work about the basic mechanisms of soil carbon sequestration that uses canopy soils from my sites in Costa Rica,” she says.

n a study published today in Cell, one of the most prominent peer-reviewed scientific journals in the field of Biochemistry & Molecular Biology, scientists from the National University of Singapore (NUS) and Imperial College London have discovered a new way by which bacteria transmit their genes, enabling them to evolve much faster than previously understood. Led by Assistant Professor John Chen from the Department of Microbiology and Immunology and the Infectious Diseases Translational Research Programme at the NUS Yong Loo Lin School of Medicine (NUS Medicine), the insights could help scientists to better understand how pathogenic bacteria evolve and become increasingly virulent and resistant to antibiotics.

The ability to share genetic material is the major driver of microbial evolution because it can transform a benign bacterium into a deadly pathogen in an instant. Phages, the viruses of bacteria, can act as conduits that allow genes to transfer from one bacterium to another by a process known as genetic transduction. Currently, there are three known mechanisms of transduction: generalised, specialised, and lateral. Lateral transduction was also discovered by the same groups of researchers in 2018, and it is at least one thousand times more efficient than the next most powerful mechanism, generalised transduction.

The new process is termed lateral cotransduction, and the architects behind this new frequency and speed in bacterial evolution are the Staphylococcus aureus pathogenicity islands (SaPIs), which are selfish DNA elements that exploit and parasitise phages and are commonly found integrated into the chromosomes of S. aureus isolates. S. aureus is a type of bacteria that can cause Staph infections in humans and animals. While it primarily manifests as skin infections, it can become life-threatening if it spreads to the bloodstream and infects organs, bones, or joints.

Professor José R. Penadés from the Department of Infectious Diseases, and Director for the Centre for Bacterial Resistance Biology at Imperial College London, said, “This breakthrough sheds light on a novel pathway through which bacteria evolve. Given the alarming surge of antibiotic-resistant superbugs, comprehending the mechanisms driving bacterial evolution becomes increasingly critical.”

This newly discovered process, lateral cotransduction, rivals lateral transduction in terms of efficiency but surpasses the latter in versatility and complexity. While lateral transduction is only known to occur when dormant phages within bacterial genomes become reactivated and initiate reproduction in the lytic cycle, lateral cotransduction can occur during the reactivation process and the infection of new bacterial cells.

Additionally, unlike phages that sacrifice their genes to transmit bacterial host DNA, SaPIs can transfer themselves completely intact with bacterial DNA through lateral cotransduction. This remarkable capability enables them to perpetually repeat the process, making them significantly more potent and efficient in transmitting bacterial genes.

Asst Prof Chen said, “Through the study, we have demonstrated that bacteria can evolve much faster than we understood. While genetic transduction has always been the exclusive domain of phages, in an unexpected twist of irony, our research has shown that parasites of the most prolific parasites on the planet (the phages) are probably the most powerful and efficient transducing agents currently known.”

The rise of superbugs has called for new ways to treat antibiotic-resistant strains. One such method that has gained traction in recent years is phage therapy, which involves the use of phages to eliminate harmful bacteria in infections and diseases. However, instead of just fighting bacteria, some therapeutic phages could turn out to be the unwitting accomplices of SaPIs or other related elements capable of lateral cotransduction.

According to Prof Penadés, “This process likely occurs in various other bacterial species as well. This groundbreaking finding marks a paradigm shift in our understanding of bacterial evolution and will immensely influence the ways we combat antibiotic resistance.”

“They (phages) could be used to destroy bacteria in the short term but end up spreading harmful genes to other cells in the long term, which could prove to be disastrous. With this new way of understanding the evolutionary mechanisms of disease-causing organisms, it is important for therapeutic phages to be carefully vetted before they are used for therapy,” said Asst Prof Chen.

Understanding the ionosphere high in the Earth’s atmosphere is important due to its effects on communications systems, satellites and crucial chemical features including the ozone layer. New insights into the activity of high energy electrons have come from a simulation study led by geophysicist Yuto Katoh at Tohoku University, reported in the journal Earth, Planets and Space.

“Our results clarify the unexpected role of the geomagnetic field surrounding the Earth in protecting the atmosphere from high energy electrons,” says Katoh.

The ionosphere is a wide region between roughly 60 and more than 600 kilometers above the Earth’s surface. It contains electrically charged particles that are a mixture of ions and free electrons generated by the interaction of the atmosphere with radiation from the sun.

Polar regions of the ionosphere are subjected to a particularly steady and energetic stream of incoming electrons in a process called electron precipitation. These ‘relativistic’ electrons move at close to the speed of light, where the effects of Einstein’s relativity theory become ever more significant. They collide with gas molecules and contribute to many phenomena in the ionosphere, including colourful auroral displays. The processes are heavily influenced by the effects of the geomagnetic field on the charged particles involved.

The Tohoku team, with colleagues in Germany and other institutions in Japan, developed a sophisticated software code that focused particular attention on simulating the effects of a relatively unstudied ‘mirror force’ on the electron precipitation. This is caused by the magnetic force acting on charged particles under the influence of the geomagnetic field.

The simulations demonstrated how the mirror force causes relativistic electrons to bounce back upwards, to an extent dependent on the angles at which the electrons arrive. The predicted effects mean that electrons collide with other charged particles higher in the ionosphere than previously suspected.

Illustrating one example of the significance of this work, Katoh comments: “Precipitating electrons that manage to pass through the mirror force can reach the middle and lower atmosphere, contributing to chemical reactions related to variations in ozone levels.” Decreased ozone levels at the poles caused by atmospheric pollution reduce the protection ozone offers living organisms from ultraviolet radiation.

Katoh emphasizes the key theoretical advance of the research is in revealing the surprising significance of the geomagnetic field and the mirror force in protecting the lower atmosphere from the effects of electron precipitation activities by keeping them further away.

“We have now started a project to combine the simulation studies used in this work with real observations of the polar ionosphere to build even deeper understanding of these crucial geophysical processes,” says Katoh.