Different areas of the brain activated depending on structural complexity of music, language

Peer-Reviewed Publication

UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER AT HOUSTON

 

IMAGE: UTHEALTH HOUSTON RESEARCHERS OBSERVED AS A BRAIN TUMOR PATIENT, WHO IS ALSO A MUSICIAN, UNDERWENT AN AWAKE CRANIOTOMY WHILE PLAYING A MINI-KEYBOARD PIANO. view more 

CREDIT: PHOTO PROVIDED BY ELLIOT MURPHY, PHD

Distinct, though neighboring, areas of the brain are activated when processing music and language, with specific sub-regions engaged for simple melodies versus complex melodies, and for simple versus complex sentences, according to research from UTHealth Houston.

The study, led by co-first authors Meredith McCarty, PhD candidate in the Vivian L. Smith Department of Neurosurgery with McGovern Medical School at UTHealth Houston, and Elliot Murphy, PhD, postdoctoral research fellow in the department, was published recently in iScience. Nitin Tandon, MD, professor and chair ad interim of the department in the medical school, was senior author.

The research team used the opportunity provided during an awake craniotomy on a young musician with a tumor in the brain regions involved in language and music. The patient heard music and played a mini-keyboard piano to map his musical skills, heard and repeated sentences and heard descriptions of objects that he then named to map his language. Musical sequences were melodic or not melodic and differed in complexity, while auditory recordings of sentences differed in syntactic complexity.

Direct brain recordings with electrodes placed on the brain surface mapped out the location and characteristics of brain activity during music and language. Small currents were passed into the brain to localize regions critical for language and music perception and production.

"This allowed us not just to obtain novel insights into the neurobiology of music in the brain, but to enable us to protect these functions while performing a safe, maximal resection of the tumor,” said Tandon, the Nancy, Clive and Pierce Runnels Distinguished Chair in Neuroscience of the Vivian L. Smith Center for Neurologic Research and the BCMS Distinguished Professor in Neurological Disorders and Neurosurgery with McGovern Medical School and a member of the Texas Institute for Restorative Neurotechnologies (TIRN) at UTHealth Houston.

“If we look purely at basic brain activation profiles for music and language, they often look pretty similar, but that’s not the full story,” said McCarty, who is also a graduate research assistant at The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences and a member of TIRN. “Once we look closer at how they assemble small parts into larger structures, some striking neural differences can be detected.”

Language and music involve the productive combination of basic units into structures. However, researchers wanted to study whether brain regions sensitive to linguistic and musical structure are co-localized, or exist in the same physical space.

“The unparalleled, high resolution of intracranial electrodes allows us to ask the kinds of questions about music and language processing that cognitive scientists have long awaited answers for, but were unable to address with traditional neuroimaging methods,” said Murphy, a member of TIRN. “This work also truly highlights the generosity of patients who work closely with researchers during their stay at the hospital.”

Overall, they found shared temporal lobe activity for music and language, but when examining features of melodic complexity and grammatical complexity, they discovered different temporal lobe sites to be engaged. Therefore, music and language activation at the basic level is shared, however when the researchers examined comparing basic melodies vs. complex melodies, or simple sentences versus complex sentences, different areas show distinct sensitivities.

Specifically, cortical stimulation mapping of the posterior superior temporal gyrus (pSTG) disrupted music perception and production, along with speech production. The pSTG and posterior middle temporal gyrus (pMTG) activated for language and music. While pMTG activity was modulated by musical complexity, pSTG activity was modulated by syntactic complexity.

Tandon resected the patient’s mid-temporal lobe tumor at Memorial Hermann-Texas Medical Center. At his four-month follow-up, the patient was confirmed to have fully preserved musical and language function, without evidence of deterioration.

The study was funded by the National Institute of Neurological Disorders and Stroke (NS098981), part of the National Institutes of Health.

Co-authors on the study included Xavier Scherschligt; Oscar Woolnough, PhD; Cale Morse; and Kathryn Snyder, all with the Vivian L. Smith Department of Neurosurgery at McGovern Medical School and TIRN. Tandon is also a faculty member at the MD Anderson UTHealth Houston Graduate School, and Snyder is a student at the school. Bradford Mahon, PhD, with the Department of Psychology and Neuroscience Institute at Carnegie Mellon University in Pittsburgh, also contributed.

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JOURNAL

iScience

DOI

10.1016/j.isci.2023.107223 

ARTICLE TITLE

Intraoperative cortical localization of music and language reveals signatures of structural complexity in posterior temporal cortex

In search of rice to reduce methane emissions

Peer-Reviewed Publication

THE ALLIANCE OF BIOVERSITY INTERNATIONAL AND THE INTERNATIONAL CENTER FOR TROPICAL AGRICULTURE

 

IMAGE: STUDY LEAD AUTHOR PAUL SOREMI IN THE FIELD. view more 

CREDIT: MARIA FERNANDA ALVAREZ

Livestock, the petroleum industry and landfills are all leading producers of methane, a potent greenhouse gas. But another significant but less well known contributor is one of the world’s most popular crops: rice. Rice plants transport methane from the flooded rice field into the atmosphere. A new paper from researchers at the Alliance of Bioversity International and CIAT has found that it is possible to lower emissions by developing new varieties of rice. 

According to the World Bank, rice farming is responsible for 10% of global methane emissions and is also a contributor to nitrous oxide and carbon dioxide emissions. Despite this, greenhouse gas emissions from rice systems, particularly in the Latin America and the Caribbean region, has been a largely untapped research area for the reduction of global emissions. 

In a new paper, “Potential of rice (Oryza sativa L.) cultivars to mitigate methane emissions from irrigated systems in Latin America and the Caribbean,” published in the journal All Earth,  researchers from the Alliance of Bioversity International and CIAT found that the transition to low-emission rice production systems can be accelerated by using differences in productivity and root qualities to breed a variety of rice that can maintain current yields but lower overall greenhouse gas emissions.

The team explored the genetic influences on methane emissions and highlighted the need to exploit and further develop hybrids that take advantage of  differences in roots and other above-ground plant anatomy on methane emissions. 

María Fernanda Álvarez, rice programme leader at the Alliance of Bioversity International and CIAT and one of the authors of the paper, explained that although the higher yielding hybrids they studied have a higher absolute methane emissions than current varieties, they produce similar methane per grain of rice. This implies that by adopting rice hybrids, farmers can achieve food security goals without significantly increasing the methane emission per grain of rice compared to lower yielding varieties. 

“We must acknowledge that it's not easy to reduce methane emissions and maintain productive rice systems, but our results suggest that there is hope,” Álvarez said. 

Reducing Rice Emissions

When soil is flooded, as in rice production, this produces low-oxygen (anaerobic) conditions in which methane-producing bacteria thrive. 

The rice plant uses aerenchyma, a spongy chimney-like plant tissue, to allow oxygen to move down into the roots and the methane-producing bacteria in the soil are using the same tube to send methane up into the atmosphere. 

Paul Abayomi S. Soremi, the paper’s first author and currently a lecturer at the Federal University of Agriculture in Abeokuta, Nigeria, explained that under submerged conditions, the roots of plants in general and rice in particular are responsible for taking up and expelling gasses, including methane. 

“The challenges to decrease methane emission through the expression of aerenchyma include the non-availability of adequate and up-to-date equipment to characterize aerenchyma, huge consumables requirement and inadequate human capacity,” he said, “This requires huge financial investment.”

Soremi explained that this aspect of methane transfer has not been fully investigated.

“There is a dearth of appropriate information on the optimization of aerenchyma to decrease methane emission under submerged conditions,” he said. 

A Lower Emissions Future 

Ngonidzashe Chirinda, a professor of sustainable tropical agriculture at Morroco’s Mohammed VI Polytechnic University, a co-author of the paper and an expert in the greenhouse gas impact of agriculture said that further research into the physiology of the plants was needed to develop the next generation of low-emissions varieties.

Chirinda explains that while there are no “silver bullets” when it comes to rice farming emissions, the hope is to get community buy-in and even potentially certify the emissions reductions in the future so that farmers are compensated for lowering emissions while maintaining or increasing their harvest.

 “To scale up, you need to incentivise the farmers to implement the good practices and if you can get a rice that is low emitting, but high yielding, they can achieve both goals,” Chirinda said, “Everyone wins: the farmer wins, the environment wins and the future wins.”

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JOURNAL

All Earth

DOI

10.1080/27669645.2023.2207941 

ARTICLE TITLE

Potential of rice (Oryza sativa L.) cultivars to mitigate methane emissions from irrigated systems in Latin America and the Caribbean

POSTMODERN SPAGYRIC HOMEOPATHY

Scientists make common pain killers from pine trees instead of crude oil

Common drugs such as paracetamol and ibuprofen can be made from a chemical from pine trees instead of crude oil products.

Peer-Reviewed Publication

UNIVERSITY OF BATH

 

IMAGE: CONVERSION OF Β-PINENE INTO PARACETAMOL AND IBUPROFEN view more 

CREDIT: UNIVERSITY OF BATH

Common drugs such as paracetamol and ibuprofen can be made from a chemical from pine trees instead of crude oil products.

• Turpentine is a waste product from the paper industry and is usually burned to generate energy.
• Around 350,000 tonnes of turpentine is generated in the world – enough to supply the global demand for paracetamol and ibuprofen (~100,000 tonnes).
• New method converts one of the components of turpentine (β-pinene) into a range of valuable chemical starting blocks for perfumes, plastics and pharmaceuticals including paracetamol and ibuprofen.
• Turpentine is a biorenewable, sustainable starting material that could replace crude oil products, and is not subject to price fluctuations of crude oil.

A team of scientists, from the University of Bath’s Department of Chemistry and Institute for Sustainability have found a way to create two of the world’s most common painkillers, paracetamol and ibuprofen, out of a compound found in pine trees, which is also a waste product from the paper industry.

It is perhaps not widely known that many common pharmaceuticals are manufactured using chemical precursors derived from crude oil, presenting a niche sustainability challenge as the world targets Net Zero.

The research team from Bath has developed a method of creating a range of pharmaceutical  precursors from biorenewable β-pinene, a component of turpentine which is a waste by-product from the paper industry (annual production >350,000 tonnes).

They successfully converted β-pinene into two everyday painkillers, paracetamol and ibuprofen, which are produced on ~100,000 tonne scales annually.

They also successfully synthesised a range of other precursor chemicals from turpentine, including 4-HAP (4-hydroxyacetophenone), which is the precursor of drugs including beta-blockers and the asthma inhaler drug, salbutamol, as well as others widely used for perfumes and in cleaning products.

They hope that this more sustainable “biorefinery” approach could replace the need for crude oil products in the chemical industry.

Dr Josh Tibbetts, Research Associate in the University’s Department of Chemistry, said: “Using oil to make pharmaceuticals is unsustainable – not only is it contributing to rising CO2 emissions, but the price fluctuates dramatically as we are greatly dependent on the geopolitical stability of countries with large oil-reserves, and it is only going to get more expensive.

“Instead of extracting more oil from the ground, we want to replace this in the future with a ‘bio-refinery’ model.

“Our turpentine-based biorefinery model uses waste chemical by-products from the paper industry to produce a spectrum of valuable, sustainable chemicals that can be used in a wide range of applications from perfumes to paracetamol.”

Instead of putting chemicals in a large reactor to create separate batches of product, the method uses continuous flow reactors, meaning production can be uninterrupted and easier to scale up.

Whilst the process in its current form may be more expensive than using oil-based feedstocks, consumers may be prepared to pay a slightly higher price for more sustainable pharmaceuticals that are completely plant-derived.

The research, funded by the Engineering and Physical Sciences Research Council, is published in the journal ChemSusChem. https://doi.org/10.1002/cssc.202300670

Biorenewable paracetamol produced by the team.

CREDIT

University of Bath

Flow reactor used in the synthesis of paracetamol where starting materials are flowed through in a continuous process to give a constant stream of products.

CREDIT

University of Bath

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JOURNAL

ChemSusChem

DOI

10.1002/cssc.202300670 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Sustainable Syntheses of Paracetamol and Ibuprofen from Biorenewable β-pinene

Is our phosphorus use sustainable? Most stakeholders doubt it

Peer-Reviewed Publication

NORTH CAROLINA STATE UNIVERSITY

A new study finds that most phosphorus stakeholders – representing a wide swath of industry, agriculture, environmental and policy interests – have significant doubts about the long-term sustainability of existing phosphorus management systems. The study underscores the complex challenges facing policymakers and other decision-makers as they attempt to ensure our continued access to a critical resource that is finite and largely non-renewable.

Phosphorus is a naturally occurring element which is used in a wide variety of industrial sectors.
For example, phosphorus is a key ingredient in agricultural fertilizers, contributing to food production on a global scale. However, phosphorus runoff also contributes to major water quality issues, such as the formation of oxygen-free “dead zones.”

“From an industry standpoint, the fertilizer, agriculture, mining, food processing and chemical manufacturing sectors all have a stake in phosphorus – it’s an incredibly important resource,” says Khara Grieger, corresponding author of the study and an assistant professor of environmental health and risk assessment at North Carolina State University. “Phosphorus stakeholders also include policymakers, wastewater treatment facilities and environmental groups who are concerned about the adverse impacts that mismanaged phosphorus has on our water quality.

“If we want to develop systems and policies that ensure long-term sustainability of phosphorus resources, we have to understand the needs, wants and concerns of relevant stakeholders,” Grieger says. “However, to date, very little has been done to understand and document how phosphorus stakeholders view phosphorus sustainability or what challenges they perceive related to ensuring sustainable phosphorus systems more broadly.”

To address this lack of information, the researchers collected survey data from 96 stakeholders involved in various aspects of phosphorus management. These study participants represent a wide variety of industry, environmental, agricultural and policy interests and have expertise in many different aspects of phosphorus management.

The researchers found that 30.2% of study participants felt that current practices regarding “the mining, use, transport, recovery, recycling or disposal of phosphorus and materials containing phosphorus” was completely unsustainable. Another 45.8% of study participants felt these practices were only slightly sustainable – which was one step up from unsustainable. Meanwhile, 14.6% felt that the practices were neither sustainable nor unsustainable, and only 4.2% of respondents felt the practices were “very sustainable.”

“If there are two key takeaway messages here, one of them is that there is very real concern among the majority of phosphorus stakeholders about the sustainability of this essential resource,” says Grieger, who is also a co-director of knowledge transfer of the National Science Foundation’s Science and Technologies for Phosphorus Sustainability (STEPS) Center headquartered at NC State. “The other takeaway is that there is no silver bullet for addressing this challenge – the needs and concerns across stakeholder groups are too varied and tend to be context and site-specific.”

However, when researchers asked study participants about what is needed to advance phosphorus sustainability, three items stood out.

“More than 50% of respondents reported that new, improved or different regulations are needed; improved management practices and procedures are needed; and new or improved technologies are needed,” Grieger says. “And the respondents who highlighted those three areas of need ran the gamut across interest groups.

“While the challenges here are thorny ones, we found this aspect of the study encouraging – because the STEPS Center is focused on addressing needs related to both technologies and management practices. And these results suggest there is support for our work in both areas.”

The paper, “What are stakeholder views and needs for achieving phosphorus sustainability?,” is published open access in the journal Environment Systems and Decisions. The paper was co-authored by Ashton Merck and Alison Deviney, who are both postdoctoral researchers at NC State; and by Anna Marshall: associate professor of sociology at the University of Illinois, Urbana-Champaign.

The work was done with support from the STEPS Center, which is a National Science Foundation Science and Technology Center funded by NSF grant 2019435. The STEPS Center focuses on addressing phosphorus sustainability challenges by integrating research across the physical, life, social and economic sciences.

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JOURNAL

Environment Systems & Decisions

DOI

10.1007/s10669-023-09917-y 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

What are stakeholder views and needs for achieving phosphorus sustainability?

Exterminating greenhouse pests with bat-inspired drones

Reports and Proceedings

SOCIETY FOR EXPERIMENTAL BIOLOGY

 

IMAGE: ULTRASONIC SPEAKER IN GREENHOUSE view more 

CREDIT: DAYO JANSEN

Researchers have been testing real-life Batman-style gadgets to eradicate moth pests from greenhouses, including bat-inspired flying drones that hunt down and destroy moths – but new research reveals that the noise from drones can alter moth flight behaviour.

“The idea of using drones as an alternative solution to eliminating moths all started in the bedroom of one of the co-owners of the PATS startup company,” says Dayo Jansen, a PhD student from student from Wageningen University and Research in the Netherlands. “He was fed up with all the mosquitoes keeping him awake and he made a drone that hunts down mosquitoes.”

Building on this idea, PATS is now creating drones and other animal-inspired technology to eradicate moth pests from large-scale plant and crop greenhouses.

While the drones are effective at removing moths, new research by Mr Jansen shows that the noise of their flight affects the moth’s flying behaviours. “After analysing the sounds, we found that it produces ultrasound in the same range as a bat would be, the moth's natural predator,” says Mr Jansen. “Some moths still ignore the noise and get eliminated quickly, but for the moths that do get scared, we doubled down on the sound with our speakers by creating an environment where some of the moths would cease to fly.”

To detect when a moth is flying in the greenhouse, Mr Jansen uses an infrared camera that can differentiate the moths from other flying insects based on wingbeat frequency and size. “This makes sure we only attack moths and not the bumblebees that are used for pollination” he says. “The moment a moth flies into detection range, a drone will spin up and hunt the moth down.”

However, several moth species behave quite erratically in response to the drones. “I study these erratic responses and try to find ways to predict the moth’s actions in the future and let the drone move where the moth is bound to go,” says Mr Jansen.

Part of this research involves playing ultrasonic noises through speakers to influence the moth’s flight behaviour. “We find out what sound each moth species is most scared of, making them cease their flight as a whole,” says Mr Jansen. “We do this firstly by figuring out which bat hunts the moth species that we want to tackle and secondly, study the tympanic hearing organ of the moths to find the sounds that they’re most sensitive to.

During the experimental setup, when a moth enters the camera’s vision, the speaker plays bursts of ultrasound and the moth’s flight behaviour is tracked – this was repeated 850 times. The behaviour of the moths was then compared to control setups where the speakers would not play ultrasound after detecting the moths.

They found that the moth behaviours fell into an array of categories, from which diving to the ground was found to be most common, causing the moths to erratically fly into the crops instead of finding a partner for reproduction. “For certain moth species we found that this has the effect of them not even flying anymore and therefore quickly diminishing their flight activity in our systems,” explains Mr Jansen.

“It has become increasingly difficult to counter agricultural pests,” says Mr Jansen. “Due to climate change, newer pest species are being introduced in previously inhabitable areas, and monoculture has become a standard in a lot of greenhouses. Greenhouse owners tend to specialize on a singular crop which has the added risk that when a suitable pest species enters the greenhouse, it finds itself in pest heaven and reproduces uncontrollably fast.

The current way of dealing with greenhouse pest infestation is often to use a tremendous number of unsustainable pesticides, but these systems hope to drive development towards futuristic and bio-inspired solutions that make pesticides a thing of the past.

Currently, the camera vision recognition system (PATS-C) is available and currently active in around 250 greenhouses across Europe. The bat-inspired drone hunting system (PATS-X) is being trialled with first customers and is to be released by the end of 2023.

“With my research we aim to dive deep into some of the most common and harmful species in the European greenhouses and make sure our systems are ready for a tailored approach against them,” concludes Mr Jansen. “We hope to illustrate the positive effect that comes from bridging the gap between biologists, engineers and industry.”

Computer vision of drone hunti [VIDEO] 

Moth flight activity during the night

CREDIT

Dayo Jansen

To make drinking water safer, WVU researcher investigates microbial communities living in pipes

Grant and Award Announcement

WEST VIRGINIA UNIVERSITY

 

IMAGE: EMILY GARNER, ASSISTANT PROFESSOR OF CIVIL AND ENVIRONMENTAL ENGINEERING AT WEST VIRGINIA UNIVERSITY, SHOWS STUDENTS HOW TO PREPARE WATER SAMPLES FOR ANALYSIS. THE SAMPLES CONSIST OF DNA EXTRACTED FROM MICROORGANISMS FOUND IN DRINKING WATER DISTRIBUTION SYSTEM SAMPLES COLLECTED. IN THE BACKGROUND IS RECENT UNIVERSITY GRADUATE MADISON HADDIX. view more 

CREDIT: WVU PHOTO

A West Virginia University engineer is working to solve the unknowns about microorganisms growing inside pipes that bring drinking water to homes and businesses.

Supported by $505,784 from a National Science Foundation CAREER award, researcher Emily Garner has launched a five-year study to learn more about biofilms. Known as “cities of microbes,” biofilms are conglomerations of fungi, algae, bacteria and other single-celled organisms that cling to each other and to surfaces like the insides of water pipes, where they become coated in protective slime.

“Many things influence how biofilms grow in drinking water distribution systems: water chemistry, the presence of disinfectants like chlorine and the forces exerted as water flows through pipes,” said Garner, an assistant professor in the Wadsworth Department of Civil and Environmental Engineering at the Benjamin M. Statler College of Engineering and Mineral Resources.

“But past research about biofilms doesn’t account for the complexities of varied flow conditions in different parts of a water distribution system. These systems can consist of hundreds of miles of buried pipes, so ensuring the chlorine disinfectant hasn’t decayed by the time it reaches all parts of the system can be a challenge.”

Garner’s lab will develop strategies for maintaining water quality throughout these complex infrastructures and offer recommendations to managers of drinking water distribution systems.

The research also includes an outreach and educational component that will bring K-12 students across West Virginia hands-on activities about water treatment and information about water sector careers.

Research that tests the waters

Rest assured, Garner said, “it’s normal and expected for biofilms to form on the inside of all drinking water pipes. Biofilms rich in organisms that are harmless to humans may even be effective at reducing the growth of harmful pathogens through competition.”

But biofilms can be also detrimental to drinking water quality. The protective environment they create can harbor dangerous microorganisms like salmonella or E. coli, and they can release particles or compounds that affect the taste, odor and color of tap water. They can also facilitate formation of harmful compounds called “disinfection byproducts.”

Garner explained water utilities control the growth of microorganisms by adding small amounts of a disinfectant like chlorine into the water.

“At low enough levels, these disinfectants are not harmful to humans but prevent growth of microorganisms like those in biofilms,” she said. “This is really important for making sure the water that arrives at your home is high-quality and safe, even though it has made a long journey of many miles from the treatment plant.”

To evaluate ways to minimize potential safety hazards, Garner will combine lab experiments with field sampling from water systems throughout West Virginia, where water quality can vary dramatically between communities.

Garner said she drinks plenty of tap water because she knows water quality is high in her home city.

“Here in Morgantown, our water is consistently compliant with all federal drinking water standards, and I drink it daily,” Garner said. “Everyone should be aware that public water systems must create an annual Consumer Confidence Report that describes their water quality and any violations of regulatory requirements for drinking water quality. You probably receive it in the mail, you can often find it online or you can contact your drinking water utility to request it. It’s a good idea to review this report to understand if your drinking water is in compliance with federal regulations.”

Students who chart the waters

Garner’s project, “Elucidating hydrodynamic drivers of microbial water quality in drinking water distribution systems,” prioritizes not only research but also education and training.

Garner will deliver an educational module, “Why Water Matters in Rural Communities,” to K-12 classrooms in West Virginia. Her goal is not only to help kids recognize water’s essential role in supporting healthy, prosperous communities, but also to increase awareness about water careers and promote recruitment of an emerging workforce into apprenticeship programs with local water utilities.

“Having well-trained water professionals is critical for ensuring community access to safe drinking water. Yet the U.S. water sector is facing an imminent workforce crisis. As the existing workforce nears retirement age, we have to raise interest in water sector jobs,” she said.

Garner has a history of leveraging her research to support local communities, especially through the Appalachian Community Technical Assistance and Training Program, in which she assists small utilities in establishing effective, sustainable management practices.

“We provide technical assistance on challenges that often arise among rural utilities,” she explained. “For example, I have partnered with the WVU student chapter of Engineers Without Borders to map the buried water infrastructure of a rural system that had no digital records of where their infrastructure was located.”

Garner will also integrate important topics for rural communities’ water and wastewater systems into courses for engineering undergraduates at WVU, addressing topics such as decentralized wastewater treatment technologies and public health engineering.

Helping plants make better use of sunlight

New findings on photosynthesis

Peer-Reviewed Publication

TECHNICAL UNIVERSITY OF MUNICH (TUM)

 

IMAGE: PROF. FRANZ HAGN (RIGHT) AND DR. UMUT GÜNSEL IN FRONT OF A STRUCTURAL MODEL OF THE TRANSPORT PROTEIN. view more 

CREDIT: ASTRID ECKERT / TUM

Plants use photosynthesis to produce oxygen, nutrients and bioenergy. But this complex biochemical process is inefficient, with only a fraction of the sun's energy actually being utilized in photosynthesis. Researchers want to change this in order to help increase the yield of cultivated crops. A research team in Munich has now discovered that the outer envelope membrane of chloroplasts could play a key role in this process.

Plants absorb carbon dioxide and use the sun and water to turn it into biomass and oxygen. Without photosynthesis, life as we know it would be impossible. However, the photosynthesis process is inefficient, since plants utilize only a small portion of the solar energy involved. Researchers around the world are trying to decode the process in order to optimize it – and to be able to produce more biomass in a shorter period of time.

Logistics as a limiting factor

A research team led by Franz Hagn, Professor for Structural Membrane Biochemistry at TUM and research group leader at Helmholtz Munich, has investigated a new approach to optimizing photosynthesis. The researchers didn't focus on the chemical photosynthesis process, instead they looked at what could be called the logistics. "Increasing the yield of simple sugars and other metabolites in the chloroplasts is the subject of intensive research," says Hagn. "But just improving the process itself won't help. The products must also be transported out of the chloroplasts across the inner and outer envelope membrane so that the plant can use them to grow."

A large number of transport proteins of the inner envelope membrane and their functionalities have already been investigated in detail. However, the role the outer envelope membrane plays in this process is by far less clear. "Among other things there was a theory that the outer envelope membrane functions as a kind of sieve which allows for almost unrestricted passage of these metabolites."

Additional transport mechanisms have to be investigated

The researchers have now shown that this is not the case. Investigating the molecular structure of a transport protein in the outer envelope membrane, they were able to determine the mechanism by which certain molecules reach the outside. The team was thus able to demonstrate that a controlled transport takes place which selects metabolites according to charge and size. "The outer envelope membrane of the chloroplasts has long been ruled out as a barrier for metabolites from photosynthesis. Now we've succeeded in showing that the membrane is probably an important limiting and regulated factor," says Hagn.

Next the scientists want to investigate the structural and functional details of further transport proteins of the outer envelope membrane. In the long term the findings could be used for example to integrate more and larger transport proteins in the outer envelope membrane so that the metabolites could make their way to the outside faster and thus boost the growth of the plant. Hagn: "Increasing the yield of for example energy plants becomes more and more important in the context of climate change, extreme weather and energy shortages."

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JOURNAL

Nature Structural & Molecular Biology

DOI

10.1038/s41594-023-00984-y 

ARTICLE TITLE

Structural basis of metabolite transport by the chloroplast outer envelope channel OEP21

The future of recycling could one day mean dissolving plastic with electricity

Peer-Reviewed Publication

UNIVERSITY OF COLORADO AT BOULDER

Chemists at the University of Colorado Boulder have developed a new way to recycle a common type of plastic found in soda bottles and other packaging. The team’s method relies on electricity and some nifty chemical reactions, and it’s simple enough that you can watch the plastic break apart in front of your eyes.  

The researchers described their new approach to chemical recycling July 3 in the journal Chem Catalysis.

The study tackles the mounting problem of plastic trash around the world. According to the Environmental Protection Agency, the United States alone produced nearly 36 million tons of plastic products in 2018. A majority of the waste winds up in landfills, said study co-author Oana Luca.

“We pat ourselves on the back when we toss something into the recycling bin, but most of that recyclable plastic never winds up being recycled,” said Luca, assistant professor in the Department of Chemistry. “We wanted to find out how we could recover molecular materials, the building blocks of plastics, so that we can use them again.”

In the new research, she and her colleagues got one step closer to doing just that.

The group focused on a type of plastic called polyethylene terephthalate (PET), which consumers encounter every day in water bottles, blister packs and even some polyester fabrics. In small-scale lab experiments, the researchers mixed bits of that plastic with a special kind of molecule then applied a small electric voltage. Within minutes, the PET began to disintegrate.

The team has a lot more work to do before its recycling tool can take a realistic bite out of the world’s plastic trash problem. But it was still fun to watch the waste, which can stick around in garbage piles for centuries, disappear in a matter of hours or days, said study lead author Phuc Pham.

“It was awesome to actually observe the reaction progress in real time,” said Pham, a doctoral student in chemistry. “The solution first turns a deep pink color, then becomes clear as the polymer breaks apart.”

One person’s trash

Luca said it’s a whole new way of thinking about the possibilities of trash. Recycling bins, she noted, may look like a good solution to the world’s plastics problem. But most municipalities around the world have struggled to collect and sort the small mountain of rubbish that people produce every day. The result: Less than one-third of all PET plastic in the U.S. comes close to being recycled (other types of plastic lag even farther behind). Even then, methods like melting plastic waste or dissolving it in acid can alter the material properties in the process.

“You end up changing the materials mechanically,” Luca said. “Using current methods of recycling, if you melt a plastic bottle, you can produce, for example, one of those disposable plastic bags that we now have to pay money for at the grocery store.”

She and her team, in contrast, want to find a way to use the basic ingredients from old plastic bottles to make new plastic bottles. It’s like smashing your Lego castle so that you can retrieve the blocks to create a whole new building.

Another’s treasure

To achieve that feat, the group turned to a process called electrolysis—or using electricity to break apart molecules. Chemists, for example, have long known that they can apply a voltage to beakers filled with water and salts to split those water molecules into hydrogen and oxygen gas.

But PET plastic is a lot harder to divide than water. In the new study, Pham ground up plastic bottles then mixed the powder into a solution. Next, he and his colleagues added an extra ingredient, a molecule known as [N-DMBI]+ salt, to the solution. Pham explained that in the presence of electricity, this molecule forms a “reactive mediator” that can donate its extra electron to the PET, causing the grains of plastic to come undone. Think of it like the chemistry equivalent of delivering a karate chop to a wooden board.

The researchers are still trying to understand how exactly these reactions take place, but they were able to break down the PET into its basic building blocks—which the group could then recover and, potentially, use to make something new. 

Deploying only tabletop equipment in their lab, the researchers reported that they could break down about 40 milligrams (a small pinch) of PET over several hours. 

“Although this is a great start, we believe that lots of work needs to be done to optimize the process as well as scale it up so it can eventually be applied on an industrial scale,” Pham said. 

Luca, at least, has some big-picture ideas for the technology.

“If I were to have my way as a mad scientist, I would use these electrochemical methods to break down many different kinds of plastic at once,” Luca said. “That way, you could, for example, go to these massive garbage patches in the ocean, pull all of that waste into a reactor and get a lot of useful molecules back.”

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JOURNAL

Chem Catalysis