Hamburg collaboration paves the way to cleaner technologies for industry

Interdisciplinary collaboration combining structural biology and microbiology provides insights on a heat-resistant enzyme from an exotic microbe, which might contribute to transition to more sustainable industrial processes

Peer-Reviewed Publication

EUROPEAN MOLECULAR BIOLOGY LABORATORY

 

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INTERDISCIPLINARITY AND AN EXCHANGE OF INNOVATIVE IDEAS ALLOWED RESEARCHERS TO GAIN INSIGHTS INTO THE STRUCTURE AND FUNCTION OF A HEAT-RESISTANT ENZYME FOUND IN AN EXOTIC MICROBE LIVING IN EXTREME CONDITIONS.

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CREDIT: ISABEL ROMERO CALVO/EMBL

During the nearly five decades of its operation, the European Molecular Biology Laboratory (EMBL) in Hamburg has developed many fruitful collaborations with other scientific institutions located in the Hamburg metropolitan area. One example is the long-lasting collaboration between researchers at EMBL Hamburg and the Center for Biobased Solutions (CBBS) at the Hamburg University of Technology (TUHH), which has recently yielded new insights into the structure and function of a lipid-degrading enzyme found in a microbe adapted to living in extreme conditions. The findings could help improve chemical processes in various branches of industry.

In this interview, Matthias Wilmanns and Garo Antranikian, who lead respective research groups at EMBL Hamburg and TUHH, discuss how their collaboration developed over almost two decades.

What motivated you to study enzymes from organisms living in extreme conditions?

 

Garo Antranikian:  Throughout my career, I was consistently motivated by the wonders of nature, which never failed to inspire my research work. Collaboration with industry further amplified this creative energy leading to the realisation of innovative technologies. We are experiencing a sort of a revolution nowadays – a transition to a circular economy and sustainable technologies that rely on biomass like starch, fats, and cellulose. Biology will play a dramatic role in it by enabling ways to use these resources more efficiently.

 

Biomass can be degraded to compounds useful for various industries, such as the food and the pharmaceutical industries. It’s possible to do this via chemical reactions, but they are not very exact and you get side reactions and contamination. However, in nature, enzymes can carry out reactions very precisely and without producing compounds that are harmful for our environment.

 

In many cases, enzymes are very specific but complex, so we need to study and understand them in more detail to develop efficient and environmentally friendly enzymatic processes useful for the industry.

 

For scientists like Matthias and I, it’s extremely interesting to learn from nature. With this knowledge and with artificial intelligence, I think it will be possible to develop completely new nature-inspired enzymes in the future, and make totally new products, such as new bioplastics.

 

That’s why we started working together, and we focused in particular on a lipid-degrading enzyme found in extremophiles – microbes adapted to extreme conditions. Enzymes from extremophiles exhibit remarkable resilience in extreme conditions. Particularly, at elevated temperatures, reactions become both faster and more efficient. This characteristic also allows the development of more sustainable and effective industrial processes.

 

Matthias Wilmanns: This was actually one of the reasons why I found this project motivating. The structures of enzymes from organisms living in extremely high temperatures are more stable and thus more likely to be solved using structural biology methods.

 

I had also other reasons, of a more private nature. The organisms adapted to extreme environments come from the most exotic places in the world, and I find it fascinating. For example, the enzyme that we worked on with Garo comes from a microbe isolated from the Solar Lake in the Middle East.

 

Finally, I have very much enjoyed working with Garo over extended periods of time, especially in recognition of the fact that he has pioneered the field of research with extremophilic organisms.

How did you start working together?

 

Matthias Wilmanns: We first met 23 years ago – in 2000. At that time, I was particularly interested in enzymes from extremophilic conditions and wanted to explore their properties at the molecular level that let them adapt to those conditions.

 

Garo Antranikian: I'm a microbiologist, so I was interested in microbial physiology – how microbes live, how they make products, how they degrade complex chemical compounds etc. And Matthias knows the technology to analyse enzyme structure, the interaction of these enzymes with other molecules, and so on.

 

With interdisciplinary research, you can get much better results, so, we need to work together. And especially in Hamburg, where we’re lucky to have so many tools and infrastructures available, Matthias and I had good opportunities to do that.

 

Matthias Wilmanns: That’s why I’m very positive about the Science City Hamburg Bahrenfeld, and its potential to stimulate scientific exchange in the metropolitan area of Hamburg. The TUHH in Hamburg- Harburg is another leading hub. This concept has the potential to evolve the city even more as a leading hub for research worldwide.

 

The research that Garo and I have been pursuing for the last two decades is now also highly relevant for the current EMBL programme ‘Molecules to Ecosystems’.

 

What challenges did you overcome to complete this work?

 

Matthias Wilmanns: Our ambition was not just to solve the structure of the enzyme, but to make it useful in terms of possible applications and learn about its mechanisms of function. That’s why we aimed to not only solve the structure, but also see how it interacts with lipid molecules as it degrades them.

 

The ability of lipids to dissolve in water is close to zero, while the enzyme is water soluble. So, there's absolutely no way to get both into a crystal (needed for X-ray crystallography experiments) using conventional methods. We had to find a way around it. It was a lucky break that the enzyme is heat-resistant, because at high temperatures, the lipids mix with the water and the enzyme a little bit – just enough for us to capture them together in an experiment.

 

What did you learn from this collaboration?

 

Garo Antranikian: Of course, scientifically, we’ve learned a lot from each other. But I’ve also learned to be patient and not to lose hope. And I’ve learned that from Matthias, because he’s more patient than I am [laughs].

 

Matthias Wilmanns: For me, Garo opened my mind to research areas I wasn’t familiar with before. The collaboration enabled me to learn about the unique research profile of the TUHH and different ways of approaching research, with potential applications very much in the mindset. Through the collaboration, I got to know many researchers with whom I later collaborated.

 

What advice would you give to other scientists who want to start interdisciplinary projects?

 

Garo Antranikian: From my experience, I got my best papers when the projects were not well planned [laughs]. This is because when you plan everything and you expect certain results, the level of innovation is very low. You should be very enthusiastic, motivated, and then try to take risks.

 

Also, you have to try to collaborate with people that you don't naturally expect to collaborate with, who are outside your discipline, and then try to create new ideas. Communication is extremely important, such as interaction with other researchers, institutions, industry etc. Without it, you can’t really get innovation.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-023-43354-4 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Discovery of a non-canonical prototype long-chain monoacylglycerol lipase through a structure-based endogenous reaction intermediate complex

ARTICLE PUBLICATION DATE

27-Nov-2023

 

Pioneering research method reveals bluefin tuna’s fate

Peer-Reviewed Publication

UNIVERSITY OF SOUTHAMPTON

 

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CLOSE-UP OF A BLUEFIN TUNA OTOLITH

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CREDIT: PROFESSOR CLIVE TRUEMAN

The return of bluefin tuna to Northern European waters is a conservation success story, but rising sea temperatures in their Mediterranean nursery grounds mean this recovery may be short-lived, according to new research led by the University of Southampton.

Temperatures expected in the Mediterranean within the next 50 years are expected to drive juvenile tuna out of the Mediterranean, where they may be accidentally caught in existing sardine and anchovy fisheries – requiring fishery managers to adapt their methods to allow tuna nurseries to establish.

Outlining the research, published in Nature, lead author Clive Trueman, Professor of Geochemical Ecology at the University of Southampton, said: “We have found that anything over 28 degrees Celsius will adversely impact bluefins’ growth. Drawing on compilations of global climate model projections, we show that most of the Mediterranean Sea will exceed that 28 degree threshold within 50 years under current predictions of climate change, making it too warm for juvenile bluefin. We would, therefore, expect the tuna to move their nursery areas, potentially into the Bay of Biscay or other cooler regions – which would place juvenile tuna within existing fisheries for species like anchovy and sardine.”

Bluefin spawn on both sides of the Atlantic Ocean, and fish typically return to their nursery area for spawning. Eastern Atlantic bluefin spend their first year in the Mediterranean. When they are approximately one year old and mature enough to regulate their body temperature, they go out into the Atlantic, sometimes crossing the Atlantic ocean searching for small prey fish like sardines, herring and mackerel, returning to the Mediterranean to spawn.

To discover the cut-off temperature for bluefins to thrive, the international research team – which comprised scientists from eight countries, including the British Antarctic Survey and the AZTI science and technology centre in Spain – used a pioneering method of analysing a tissue called the otolith. The otolith, found behind the brains of bony fish, has long been used reveal a fish’s age, but the new research used the chemistry of tuna otoliths to measure the pace of life of bluefin tuna.

Professor Trueman, who pioneered the otolith decoding method, explained: “All fish have a stony tissue in their ear called an otolith, or ‘ear stone’, which enables them to perceive noise and to balance. Our new work uses variations in the levels of natural stable isotopes of carbon and oxygen in the otolith to reveal each tuna’s individual metabolic rate. This can tell us when waters are getting too hot for the fish to handle -it’s like a natural fitness tracker.”

Bluefins are the largest tuna, at up to three metres long, and one of the fastest, most powerful fish in the sea, capable of leaping out of the water at 43 miles per hour. They are also highly valuable, selling for thousands of pounds for their meat, a delicacy in sushi and sashimi.

ENDS

Bluefin tuna

CREDIT   Iñigo Onandia

JOURNAL

Nature

DOI

10.1038/s41467-023-41930-2 

ARTICLE TITLE

Thermal sensitivity of field metabolic rate predicts differential futures for bluefin tuna juveniles across the Atlantic Ocean

ARTICLE PUBLICATION DATE

27-Nov-2023

 

Deepfake smiles matter less

The perceptual and emotional impact of deepfakes

Peer-Reviewed Publication

TECHNISCHE UNIVERSITÄT BERLIN – SCIENCE OF INTELLIGENCE

 

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HOW DO WE DISTINGUISH BETWEEN REAL AND GENERATED IMAGES OF HUMAN EMOTIONS, AND HOW CAN SCIENTIFIC RESEARCH UNDERSTAND THE WAYS IN WHICH OUR BRAINS DIFFERENTIATE BETWEEN REAL AND ARTIFICIALLY CREATED EMOTIONAL CUES?

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CREDIT: IMAGE GENERATED VIA JASPER ILLUSTRATOR BY ANNA EISERBECK AS A RESPONSE TO THE PROMPT "SMILING FACE, VECTOR ART"

In our digital time, where artificial intelligence (AI) crafts deceptively realistic human faces, the emergence of deepfake technology may blur the boundaries between reality and digital fabrication. These AI-generated faces, though technologically astounding, carry a weight of societal implications that demand a thorough examination. A recent study published in Scientific Reports and conducted by Science of Intelligence (SCIoI) scientists Anna Eiserbeck, Martin Maier, Julia Baum, and Rasha Abdel Rahman, delves into the psychological and neural repercussions tied to the perception of AI-generated faces, especially focusing on the emotional expressions they portray.

Products of generative artificial intelligence, such as deceptively real-looking photos and videos of people, known as deepfakes, are becoming increasingly common. Until now, however, it was unclear how knowing that a face might or might not be real affects how we perceive it and respond to it emotionally. In their new study, the researchers analyzed facial expression ratings and brain responses to smiling, angry, and neutral faces that participants assumed were either real or computer-generated. The results show that a computer-generated smile matters less to us on several levels: it is perceived as less intense, elicits a weaker emotional response in the brain, and appears to give us pause. Angry faces, on the other hand, remain equally threatening, whether we believe them to be genuine or not. These fundamental new findings have implications for how we as a society will deal with deepfakes, both when they are used for good and for ill.

Deepfakes and the Human Brain: A study of Perception and Emotional Evaluation

The study, involving 30 participants and utilizing EEG technology, explored the effects of the belief that a portrayed individual iseither real or deepfake on psychological and neural measures of face perception. In the words of SCIoI researcher Martin Maier, “When confronted with smiling faces marked as deepfakes, participants showed reduced perceptual and emotional responses, and a slower evaluative process as opposed to when the faces were marked real. Intriguingly, this impact was not mirrored in the perception of negative expressions, which remained consistent whether believed to be real or fake.” The findings highlight a complex interplay of emotional valence and presumed authenticity, and mark the first time a distinction has been drawn in the psychological impact between positive and negative expressions portrayed by deepfakes. “When real and fake faces are otherwise indistinguishable, perception and emotional responses may crucially depend on the prior belief that what you are seeing is, in fact, real or fake,“ added Rasha Abdel Rahman, principal investigator of the study.

In order to reach these conclusions, the researchers looked at how the brain’s response to images of faces evolves over time, focusing on three stages: early visual perception (up to 200 milliseconds after a face was shown, before we are even aware of seeing it), reflexive emotional processing (at 200 – 350 milliseconds, reflecting our immediate emotional reactions), and higher-level evaluative processing (at 350 milliseconds and later, marking a more thoughtful consideration). They used a method called Event-Related Potentials (ERPs) to track these stages. The findings showed that when people looked at smiles they thought were created by deepfake technology, their typical early visual and emotional responses were weaker. Understanding this has direct implications for different situations in which we may encounter deepfakes: when used, for instance, to bring back younger versions of movie characters, the hope is that the emotional expressions of artificially generated characters appear just as lively and genuine as a real actor. In these situations, the study results suggest, knowing that the character is artificially generated may compromise its impact, especially for positive emotions. When used in the context of misinformation campaigns, the results suggest that artificially generated negative contents may stick, even though observers may suspect that the images are fake.

Implications and Future Directions in Deepfake Technology

The findings of this study serve as a cornerstone in understanding the behavioral and neural dynamics of human interaction with AI-generated faces, while the discoveries underscore the necessity for a nuanced approach in devising policies and strategies to navigate the growing sphere of deepfake technology. The results also provide a starting point for further explorations into other domains of AI-generated content such as text, visual art, or music. As deepfake technology continues to evolve, nurturing a profound understanding of its psychological and neural impact becomes central to both optimally using its potential to benefit society, and fortify societal resilience against the various challenges it poses.

Defending your voice against deepfakes

McKelvey engineers prevent synthesis of deceptive speech by making it more difficult for AI tools to read voice recordings

Reports and Proceedings

WASHINGTON UNIVERSITY IN ST. LOUIS

 

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OVERVIEW OF HOW ANTIFAKE WORKS.

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CREDIT: IMAGE COURTESY OF NING ZHANG, MCKELVEY SCHOOL OF ENGINEERING, WASHINGTON UNIVERSITY IN ST. LOUIS

Recent advances in generative artificial intelligence have spurred developments in realistic speech synthesis. While this technology has the potential to improve lives through personalized voice assistants and accessibility-enhancing communication tools, it also has led to the emergence of deepfakes, in which synthesized speech can be misused to deceive humans and machines for nefarious purposes.

In response to this evolving threat, Ning Zhang, an assistant professor of computer science and engineering at the McKelvey School of Engineering at Washington University in St. Louis, developed a tool called AntiFake, a novel defense mechanism designed to thwart unauthorized speech synthesis before it happens. Zhang presented AntiFake Nov. 27 at the Association for Computing Machinery’s Conference on Computer and Communications Security in Copenhagen, Denmark.

Unlike traditional deepfake detection methods, which are used to evaluate and uncover synthetic audio as a post-attack mitigation tool, AntiFake takes a proactive stance. It employs adversarial techniques to prevent the synthesis of deceptive speech by making it more difficult for AI tools to read necessary characteristics from voice recordings. The code is freely available to users.

“AntiFake makes sure that when we put voice data out there, it’s hard for criminals to use that information to synthesize our voices and impersonate us,” Zhang said. “The tool uses a technique of adversarial AI that was originally part of the cybercriminals’ toolbox, but now we’re using it to defend against them. We mess up the recorded audio signal just a little bit, distort or perturb it just enough that it still sounds right to human listeners, but it’s completely different to AI.”

To ensure AntiFake can stand up against an ever-changing landscape of potential attackers and unknown synthesis models, Zhang and first author Zhiyuan Yu, a graduate student in Zhang’s lab, built the tool to be generalizable and tested it against five state-of-the-art speech synthesizers. AntiFake achieved a protection rate of over 95%, even against unseen commercial synthesizers. They also tested AntiFake’s usability with 24 human participants to confirm the tool is accessible to diverse populations.

Currently, AntiFake can protect short clips of speech, taking aim at the most common type of voice impersonation. But, Zhang said, there’s nothing to stop this tool from being expanded to protect longer recordings, or even music, in the ongoing fight against disinformation.

“Eventually, we want to be able to fully protect voice recordings,” Zhang said. “While I don’t know what will be next in AI voice tech — new tools and features are being developed all the time — I do think our strategy of turning adversaries’ techniques against them will continue to be effective. AI remains vulnerable to adversarial perturbations, even if the engineering specifics may need to shift to maintain this as a winning strategy.”

***

Yu Z, Zhai S, and Zhang N. AntiFake: Using adversarial audio to prevent unauthorized speech synthesis. Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security, Nov. 26-30, 2023. DOI: https://doi.org/10.1145/3576915.3623209. Code: https://sites.google.com/view/yu2023antifake.

This work was supported by the National Science Foundation and Army Research Office.

Originally published on the McKelvey School of Engineering website.

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DOI

10.1145/3576915.3623209 

ARTICLE TITLE

AntiFake: Using Adversarial Audio to Prevent Unauthorized Speech Synthesis

 

Quality of tidal mudflats changes in gas extraction area of Wadden Sea

Peer-Reviewed Publication

ROYAL NETHERLANDS INSTITUTE FOR SEA RESEARCH

 

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SIEVING ONE OF THE NEARLY 5,000 SOILS SAMPLES TAKEN WITH SIBES ON THE INTERTIDAL MUDFLATS OF THE DUTCH WADDEN SEA. CREDITS: KEES VAN DE VEEN

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CREDIT: KEES VAN DE VEEN

As tidal flats subside due to gas extraction, their composition changes. This is shown in a paper that is published in this month’s Journal of Applied Ecology. "The average grain size in the parts of the mudflats where gas is extracted has decreased over 10% in 12 years. With that, sand is getting finer," says NIOZ researcher Allert Bijleveld. In this period, the composition of the benthic life in subsided areas has also changed in comparison to similar areas where subsidence due to gas extraction did not occur.

Long-term monitoring

The data on soil composition and benthic life are derived from the long-term monitoring program SIBES. In this Synoptic Intertidal BEnthic Survey, soil has been sampled annually for 15 years along a web of nodes spaced every 500 meters across the intertidal mud flats. In total, this includes about five thousand sampling locations. SIBES shows that the grain size in the areas that are affected by gas extraction around Ameland decreased by an average of 1 micrometer each year between 2008 and 2020, while no decrease was seen in reference areas. Over the entire period, the average grain size decreased from 154 to 138 micrometers. Bijleveld: "This means that there is increasingly fine soil material in the ‘bowl’ that is created by gas extraction. That may have consequences for the benthic animals that live there."

Altered life

This study provides the first indication of these alterations in benthic life. The total biomass in the subsided area decreased slightly, although that decrease was not statistically significant compared to the reference areas. The composition of the bottom life did change statistically significant  in favor of animals that prefer deeper bottoms, such as cat worms. Conversely, there has been a reduction in animals that prefer shallow mudflats, such as mudsnails, for example.

Hand on tap

In the legal permit for mining activities under the Wadden Sea World Heritage Site, it was agreed upon that gas and salt will be extracted ‘with a hand on the tap’. According to the permit, if gas extraction has effects on natural values, extraction must be slowed down. Because 'natural values' are difficult to measure, attention is primarily paid to subsidence. This research now shows that subsidence in itself is not a good signal for a vigilant hand on the tap. Bijleveld: "Strictly spoken, there has been no net subsidence in recent decades, because the affected area has been refilled on average. But the quality of the soil did change and with it the composition of soil life."

The Dutch petrol company NAM has been extracting gas from under the mud flats near Ameland since the 1980’s. The gas extraction area is currently comprised of more silt than expected. However, due to a lack of proper monitoring in the time before extraction began, it is now impossible to determine with certainty whether the silt was already present or if it was caused by the extraction. This research gives a preliminary indication of the latter.

Out of sight

Bijleveld advocates for the inclusion of long-term research such as the SIBES monitoring program in decisions regarding mining and other activities in the Wadden Sea. "For the legally required 'hand on the tap,' the salt extraction around Harlingen now only looks at the bottom at a very limited number of stations. This leaves the actual effects of subsidence out of sight. For a serious assessment of effects, it is necessary to start measuring even before an intervention and to automatically monitor comparable areas as well through an extensive and long-term study such as SIBES. In addition to any net decrease in the soil elevation, the composition of the soil and soil life in particular, should become a measure," Bijleveld argues.

Taking a soil sample from the boat to determine sediment composition and biodiversity of benthic life. Credits: Kees van de Veen.

Cockles that were collected at a sampling station. Credits: Kees van de Veen.

CREDIT

Kees van de Veen

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METHOD OF RESEARCH

News article

ARTICLE TITLE

Quality of tidal mudflats changes in gas extraction area of Wadden Sea

 

Natural products used in Ayurvedic treatments alleviate symptoms of depression in fruit flies

Mainz University and the US-American BENFRA Center have jointly demonstrated the effect of botanical products used in traditional Asiatic medicine on depressive states

Peer-Reviewed Publication

JOHANNES GUTENBERG UNIVERSITAET MAINZ

 

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THE LEVEL OF MOTIVATION OF THE FRUIT FLY DROSOPHILA CAN BE DEDUCED ON THE BASIS OF WHETHER IT ATTEMPTS TO CLIMB OVER GAPS IT ENCOUNTERS WHEN WALKING. IN A DEPRESSION-LIKE STATE, THE FRUIT FLY IS LESS LIKELY TO DO SO. IN THE BACKGROUND ARE LEAVES OF CENTELLA ASIATICA, THE INDIAN PENNYWORT.

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CREDIT: PHOTO/©: HELEN HOVOET, HANS-HERMANN HUBER

Chronic exposure to stress can lead to the development of depression-like disorders that manifest as a lack of motivation – even in the fruit fly Drosophila melanogaster. As a result, the insects show less courtship behavior, are less interested in stopping to ingest sweet nutrients, and are less willing to climb a gap in the experimental setup. Traditional medicinal plants, however, can – to some extent – alleviate some of the associated symptoms, as observed by researchers at Johannes Gutenberg University Mainz (JGU) in Germany in collaboration with the BENFRA Botanical Dietary Supplements Research Center in Portland, Oregon. The researchers have shown that two plants used in Ayurvedic medicine can improve resilience to chronic stress when used prophylactically in the flies. Despite their stressed state, they then no longer displayed behavior consistent with depression. Papers on their studies of the two plant materials have been published in Nutrients.

Plants containing biologically active ingredients can help the organism deal with stress

The JGU research group led by Professor Roland Strauss has been using the Drosophila melanogaster model to analyze the underlying mechanisms involved in resilience to stress and the effects of stress on the nervous system. "Chronic stress can induce depression-like states also in the fruit fly, and these become apparent in changes to their behavior," explained Strauss. In this most recent research context, his group cooperated with the BENFRA Botanical Dietary Supplements Research Center in the United States of America. The center investigates botanicals that enhance neurological and functional resilience in aging.

The Mainz-based researchers focus on testing extracts of botanicals and natural substances that are known to be used in traditional Asian medicine and are also marketed as dietary supplements. The idea is that certain plants contain above average amounts of active constituents or substances that themselves demonstrate particularly high levels of biological activity. These so-called adaptogens can help our bodies adapt to increased physical and emotional stress.

"An advantage over conventional drugs could be that medicinal plants contain blends of various active botanical substances that act on different sites of the stress axis," said Helen Holvoet, a doctoral candidate in the team of Professor Strauss and lead author of the two papers. "Because they have a synergistic effect on counteracting stress, they may cause fewer undesirable effects than if the substances themselves were administered alone in pure form." Another potential advantage is that dietary supplements can be used as complementary medication in association with pharmacotherapies.

In the joint project, Strauss' team tested their approach for the treatment of stress using two Ayurvedic medicinal plants, namely Withania somnifera (known as ashwagandha or the sleep berry) and Centella asiatica (the Indian pennywort). The research partners were able to demonstrate that, when administered prophylactically, both plants enhanced the resilience to chronic stress so that the flies exposed to stress did not get into a depression-like state in the first place.

Chlorogenic acid identified as substance relevant to the treatment of stress

"In the case of Withania somnifera, we found that the way of preparing the root makes a difference – as aqueous extracts provided better prophylactic effects than extracts in alcohol," explained Dr. Burkhard Poeck, who was also involved in the experiments. This surprising result does indicate how important it is to pay attention to the production methods used for dietary supplements.

The team in Mainz and their cooperation partners in Portland obtained an even more impressive result when experimenting with Centella asiatica. They were actually able to identify a specific component, chlorogenic acid, acting as a prophylactic, anti-stress substance. Chlorogenic acid is present in many botanicals, in particularly high levels in coffee beans, for example. It is also found in traditional medicinal herbs such as valerian (Valeriana officinalis) and St. John’s wort (Hypericum perforatum), the stress-relieving potential of which have long been known.

The analysis of such medicinal substances not only provides general information on their effects on neuronal stress, but it can also offer starting points for fundamental resilience research. "In this case, we were able to pinpoint a relevant target protein for chlorogenic acid in Drosophila, the protein phosphatase calcineurin," said Professor Roland Strauss, explaining additional research results. In humans, calcineurin is present in many body organs and there are exceptionally high concentrations in the nervous system. There it interacts with numerous other proteins and mediates many signaling pathways.

The uptake of sugar and adaptogens can alleviate and even prevent depression-like states in the fruit fly Drosophila.

CREDIT

photo/©: Tim Hermanns

Publications:

• H. Holvoet et al., Chlorogenic Acids, Acting via Calcineurin, Are the Main Compounds in Centella asiatica Extracts That Mediate Resilience to Chronic Stress in Drosophila melanogaster, MDPI Nutrients, 16 September 2023,
  DOI: 10.3390/nu15184016
  https://www.mdpi.com/2072-6643/15/18/4016
• H. Holvoet et al., Withania somnifera Extracts Promote Resilience against Age-Related and Stress-Induced Behavioral Phenotypes in Drosophila melanogaster; a Possible Role of Other Compounds besides Withanolides, MDPI Nutrients, 22 September 2022,
  DOI: 10.3390/nu14193923
  https://www.mdpi.com/2072-6643/14/19/3923

Related links:

• https://idn.biologie.uni-mainz.de/ – Institute of Developmental Biology and Neurobiology (IDN) at JGU
• https://www.ohsu.edu/benfra-bdsrc – BENFRA Botanical Dietary Supplements Research Center

Read more:

• https://press.uni-mainz.de/towards-a-better-understanding-of-depression/ – press release "Towards a better understanding of depression" (16 Sept. 2022)
• https://press.uni-mainz.de/memory-research-fruit-flies-learn-their-body-size-once-for-an-entire-lifetime/ – press release "Memory research: Fruit flies learn their body size once for an entire lifetime" (21 Aug. 2019)
• https://press.uni-mainz.de/short-term-memory-in-fruit-flies-shows-age-related-decline/ – press release "Short-term memory in fruit flies shows age-related decline" (14 March 2018)
• https://press.uni-mainz.de/a-backup-copy-in-the-central-brain-how-fruit-flies-form-orientation-memory/ – press release "A backup copy in the central brain: How fruit flies form orientation memory" (7 March 2017)

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JOURNAL

Nutrients

DOI

10.3390/nu15184016 

ARTICLE TITLE

Chlorogenic Acids, Acting via Calcineurin, Are the Main Compounds in Centella asiatica Extracts That Mediate Resilience to Chronic Stress in Drosophila melanogaster

 

New research finds taste perception of ultra-processed foods no better than less processed foods

Peer-Reviewed Publication

UNIVERSITY OF BRISTOL

The study, led by Bristol’s Nutrition and Behaviour Group, wanted to test the common but largely untested assumptions that food energy density (calories per gram), level of processing, and carbohydrate-to-fat ratio are key factors influencing food liking and desirability.

In the experiment, involving 224 adult volunteers, participants were presented with colour images of between 24 and 32 familiar foods, varying in energy density, level of processing (including UPFs), and carbohydrate-to-fat ratio. There were 52 different foods in total, including avocado, grapes, cashew nuts, king prawns, olives, blueberry muffin, crispbread, pepperoni sausage, and ice cream.

Participants were then asked to rate the foods for taste pleasantness (liking), desire to eat, sweetness, and saltiness while imagining tasting them. The validity of this method was confirmed by, for example, finding a strong relationship between sweetness ratings and food sugar content.

Results from the study showed that, on average, UPFs were no more liked or desired than processed or unprocessed foods. However, foods that combined more equal amounts (in calories) of carbohydrate and fat, were more liked and desired than foods containing the same number of calories mostly as carbohydrate, or mostly as fat. This is known, from previous research, as the ‘combo’ effect.

Further results revealed that foods with higher amounts of dietary fibre were less liked and desired, and foods tasting more intense (mainly related to the level of sweetness and saltiness), were more liked and desired.

Professor Peter Rogers in the School of Psychological Science and the study’s lead author, commented that the results for UPFs were surprising.  He said: ”Our results challenge the assumption that ultra-processed foods are ‘hyperpalatable’, and it seems odd that this has not been directly tested before.

“However, whilst ultra-processing didn’t reliably predict liking (palatability) in our study, food carbohydrate-to-fat ratio, food fibre content, and taste intensity did – actually, together, these three characteristics accounted for more than half of the variability in liking across the foods we tested.

“The results for sweetness and saltiness, are consistent with our innate liking for sweetness and saltiness. And the results for carbohydrate-to-fat ratio and fibre might be related to another important characteristic that determines food liking.

“Our suggestion is that humans are programmed to learn to like foods with more equal amounts of carbohydrate and fat, and lower amounts of fibre, because those foods are less filling per calorie. In other words, we value calories over fullness.

“In turn, this trait helps us to maximise calorie intake and build up fat reserves when food is abundant – which is adaptive in circumstances when food supplies are uncertain or fluctuate seasonally, but not when food is continuously available in excess of our immediate needs.”

The Nutrition and Behaviour Group are currently testing the calories versus fullness idea in further studies of food liking and meal preferences, including across different countries and cuisines.

This research was funded by the University of Bristol’s School of Psychological Science.

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JOURNAL

Appetite

DOI

10.1016/j.appet.2023.107124 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Evidence that carbohydrate-to-fat ratio and taste, but not energy density or NOVA level of processing, are determinants of food liking and food reward

ARTICLE PUBLICATION DATE

27-Nov-2023