Neural network helps design brand new proteins

 With their intricate arrangements and dynamic functionalities, proteins perform a plethora of biological tasks by employing unique arrangements of simple building blocks where geometry is key. Translating this nearly limitless library of arrangements into their respective functions could let researchers design custom proteins for specific uses.

In Journal of Applied Physics, from AIP Publishing, Markus Buehler of the Massachusetts Institute of Technology combined attention neural networks, often referred to as transformers, with graph neural networks to better understand and design proteins. The approach couples the strengths of geometric deep learning with those of language models not only to predict existing protein properties but also to envision new proteins that nature has not yet devised.

"With this new method, we can utilize all that nature has invented as a knowledge basis by modeling the underlying principles," Buehler said. "The model recombines these natural building blocks to achieve new functions and solve these types of tasks."

Owing to their complex structures, ability to multitask, and tendency to change shape when dissolved, proteins have been notoriously difficult to model. Machine learning has demonstrated the ability to translate the nanoscale forces governing protein behavior into working frameworks describing their function. However, going the other way -- turning a desired function into a protein structure -- remains a challenge.

To overcome this challenge, Buehler's model turns numbers, descriptions, tasks, and other elements into symbols for his neural networks to use.

He first trained his model to predict the sequencing, solubility, and amino acid building blocks of different proteins from their functions. He then taught it to get creative and generate brand new structures after receiving initial parameters for a new protein's function.

The approach allowed him to create solid versions of antimicrobial proteins that previously had to be dissolved in water. In another example, his team took a naturally occurring silk protein and evolved it into various new forms, including giving it a helix shape for more elasticity or a pleated structure for additional toughness.

The model performed many of the central tasks of designing new proteins, but Buehler said the approach can incorporate even more inputs for more tasks, potentially making it even more powerful.

"A big surprise element was that the model performed exceptionally well even though it was developed to be able to solve multiple tasks. This is likely because the model learns more by considering diverse tasks," he said. "This change means that rather than creating specialized models for specific tasks, researchers can now think broadly in terms of multitask and multimodal models."

The broad nature of this approach means this model can be applied to many areas outside protein design.

"While our current focus is proteins, this method has vast potential in materials science," Buehler said. "We're especially keen on exploring material failure behaviors, aiming to design materials with specific failure patterns."

Lengthy screen time associated with childhood development delays

 The amount of screen time spent by one-year-olds is associated with developmental delays. This finding, by researchers at Tohoku University, with collaborators at Hamamatsu University School of Medicine, was published in the journal JAMA Pediatrics.

The research examined 7,097 mother-child pairs participating in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Each child's screen time exposure was assessed using parental questionnaires, covering viewing of televisions, video game displays, tablets, mobile phones and other electronic devices with visual displays.

The children in the study were almost evenly split between boys (51.8%) and girls (48.2%). Their screen time exposure was assigned to the categories of less than one hour (48.5% of subjects), from one to less than two hours (29.5%), from two to less than four hours (17.9%), and four or more hours (4.1%).

The children's development was assessed at two and four years of age in the five domains of communication, gross motor, fine motor, problem solving, and personal and social skills. Previous studies in the field have generally not broken development down into different domains, therefore offering a less refined view.

The association between screen time at age one and later developmental delay was assessed using an established statistical technique, revealing a dose-response association; meaning that the level of developmental delay (the response) was correlated to the amount (dose) of screen time.

For the children aged two, increased screen time when aged one was associated with developmental delays in all domains apart from gross motor skills. By the age of four however, increased screen time was associated with developmental delays in only the communication and problem-solving domains.

"The differing levels of developmental delays in the domains, and the absence of any detected delay in some of them at each stage of life examined, suggests that the domains should be considered separately in future discussions of the association between screen time and child development," says Tohoku University epidemiologist Taku Obara, corresponding author of the research article.

One reason for undertaking this study was recent evidence published by the World Health Organization and the American Academy of Pediatrics suggesting that only a minority of children are meeting guidelines for limiting screen time exposure. The guidelines were designed to ensure that children engage in sufficient physical activity and social interaction.

"The rapid proliferation of digital devices, alongside the impact of the COVID pandemic, has markedly increased screen time for children and adolescents, but this study does not simply suggest a recommendation for restricting screen time. This study suggests an association, not causation between screen time and developmental delay" says Obara. "We use the term 'delay' in accordance with previous research, but it is debatable whether this difference in development is really a 'delay' or not. We would like to gain deeper insight in future studies by examining the effects of different types of screen exposure."

Brain signals transformed into speech through implants and AI

 Researchers from Radboud University and the UMC Utrecht have succeeded in transforming brain signals into audible speech. By decoding signals from the brain through a combination of implants and AI, they were able to predict the words people wanted to say with an accuracy of 92 to 100%. Their findings are published in the Journal of Neural Engineering this month.

The research indicates a promising development in the field of Brain-Computer Interfaces, according to lead author Julia Berezutskaya, researcher at Radboud University's Donders Institute for Brain, Cognition and Behaviour and UMC Utrecht. Berezutskaya and colleagues at the UMC Utrecht and Radboud University used brain implants in patients with epilepsy to infer what people were saying.

Bringing back voices

'Ultimately, we hope to make this technology available to patients in a locked-in state, who are paralyzed and unable to communicate,' says Berezutskaya. 'These people lose the ability to move their muscles, and thus to speak. By developing a brain-computer interface, we can analyse brain activity and give them a voice again.'

For the experiment in their new paper, the researchers asked non-paralyzed people with temporary brain implants to speak a number of words out loud while their brain activity was being measured. Berezutskaya: 'We were then able to establish direct mapping between brain activity on the one hand, and speech on the other hand. We also used advanced artificial intelligence models to translate that brain activity directly into audible speech. That means we weren't just able to guess what people were saying, but we could immediately transform those words into intelligible, understandable sounds. In addition, the reconstructed speech even sounded like the original speaker in their tone of voice and manner of speaking.'

Researchers around the world are working on ways to recognize words and sentences in brain patterns. The researchers were able to reconstruct intelligible speech with relatively small datasets, showing their models can uncover the complex mapping between brain activity and speech with limited data. Crucially, they also conducted listening tests with volunteers to evaluate how identifiable the synthesized words were. The positive results from those tests indicate the technology isn't just succeeding at identifying words correctly, but also at getting those words across audibly and understandably, just like a real voice.

Limitations

'For now, there's still a number of limitations,' warns Berezutskaya. 'In these experiments, we asked participants to say twelve words out loud, and those were the words we tried to detect. In general, predicting individual words is less complicated than predicting entire sentences. In the future, large language models that are used in AI research can be beneficial. Our goal is to predict full sentences and paragraphs of what people are trying to say based on their brain activity alone. To get there, we'll need more experiments, more advanced implants, larger datasets and advanced AI models. All these processes will still take a number of years, but it looks like we're heading in the right direction.'

Surprising study results: Students are bored during exams

 In the case of boredom, we think of many situations in life but intuitively not of exams. However, an international team of academics led by Thomas Götz from the University of Vienna has now studied exactly this phenomenon of test boredom for the first time and found remarkable results. According to the study, school students are actually very bored during exams. The study also showed that utter boredom has a negative effect on exam results. The research results have been published recently in the Journal of Educational Psychology.

Although boredom is currently a very intensively studied phenomenon, test boredom has so far been completely ignored in the research. For the first time and on an international basis, psychologists from the University of Vienna, the University of Konstanz, the University of Zurich, the University of Applied Sciences and Arts Northwestern Switzerland, the LMU Munich, the City University of New York, the University of Essex and the Australian Catholic University (Sidney) have now been able to show that test boredom does actually occur and that it clearly deteriorates performance. The main causes were being both underchallenged and overchallenged during the exam. In addition, test boredom was significantly higher when the exam content had no personal relevance for the students. The main result of the study was that a high level of test boredom had a negative effect on exam results.

The academics proposed the so-called abundance hypothesis for the first time in their study, which they were able to confirm. On the one hand, the abundance hypothesis states that boredom especially deteriorates exam performance if students are overchallenged, because all mental resources would have to be allocated to completing the tasks, i.e. those that are used for experiencing boredom but are no longer available for working on the tasks. On the other hand, in the case of boredom as a result of being underchallenged, resources are available in abundance for processing the tasks anyway.

Exam tasks should relate to the reality of students' lives

In the study, a total of 1,820 German students in the 5th to 10th grades were examined. Questions about the extent of boredom, of being underchallenged and overchallenged and the personal relevance of the tasks were directly included in the test, between the different tasks.

From the study results, the researchers also derive some recommendations for teachers and guardians. "In order to combat test boredom, teachers should prepare exam tasks in such a way that they relate to the reality of students' lives. In addition, the tasks should not be very underchallenging or overchallenging," explains educational psychologist Thomas Götz from the University of Vienna, "Parents or guardians can also support young people by starting an open conversation about possible overchallenging or underchallenging tasks at school. Especially in the case of being overchallenged at school, it is important to react quickly to avoid boredom and also other negative consequences, such as a downward spiral of poor performance."

This first study of test boredom also opens up a completely new field of research. The academics are making a decisive contribution to clarifying the negative effects of boredom in school. "A large number of studies already show that boredom has not only a detrimental effect on learning and performance but also on mental and physical health. With our work, we are now expanding the view to a central area in the everyday school life of children and adolescents, namely exams," says Götz.

Study reveals important associations between gut microbiome and eczema in infancy

 A new study has revealed important associations between the gut microbiome and eczema in infancy and has established the basis for the potential prevention and treatment of eczema via modulation of the gut microbiota. The study was published in mSystems, a journal of the American Society for Microbiology.

"The problem of eczema is increasing, and our study shows it could be a result of unwanted changes in the gut bacterial content. The first year of life could be a critical period to restore the gut bacteria to a more desirable composition," said the study's principal investigator Paul Chan, M.D., professor of microbiology at The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.

In the new study, Dr. Chan and colleagues invited pregnant women who were close to term to participate in the research. They collected their information on health, lifestyle and events during pregnancy and delivery. After delivery, the researchers visited the women and collected information on their babies' diet, health and medication. The researchers arranged follow-up clinics to check the babies' health conditions and any eczema problems. The researchers characterized the development and determinants of the gut microbiome in a cohort of 112 term Chinese children by sequencing 713 stool samples collected at nine time points from birth to 3 years of age using 16S rRNA gene sequencing.

The researchers revealed alterations in the composition and alpha and beta diversity of the gut microbiota across the first 3 years of life. They identified mode of delivery, feeding mode and intrapartum antibiotics as the major determinants of the early-life gut microbiome, the effects of all of which persisted up to 12 months. Importantly, by conducting a nested case-control study, they showed that alterations in the infant gut microbiota precede the development of eczema. Interestingly, they identified a depletion of Bacteroides and an enrichment of Clostridium sensu stricto 1 in the gut microbiome of infants with eczema at 1 year old. The same patterns were also observed in C-section born infants within the same time frames, suggesting a role of the gut microbiota in previously reported associations between C-section and increased risk of eczema.

"Our study found that the gut bacterial content of babies changes drastically over the first 3 years of life," said Dr. Chan. "The mode of delivery and feeding, and the use of antibiotics around the time of delivery affects the gut bacterial content. We observed characteristic changes in the gut bacterial content before the babies present with eczema. Remarkably, those bacterial changes were also observed in babies delivered by C-section. Nevertheless, the link between C-section and eczema requires further studies to verify. Gut bacteria may play a role in preventing or treating eczema."

Half as many AF patients dying of heart attacks and strokes in the UK now

 Patients living with one of the UK's most common heart rhythm conditions are 50% less likely to die from a heart attack or stroke than they were at the start of the millennium, new research has found.

Analysis of the health records of more than 70,000 patients newly diagnosed with atrial fibrillation (AF) showed that mortality from related cardiovascular and cerebrovascular diseases more than halved over the 16-year study period.

AF is associated with an increased risk of stroke.

The research showed that dementia now accounts for more deaths within one year of an AF diagnosis than acute stroke, heart attack and heart failure combined, demonstrating the need for more research into the link between dementia and AF.

The study team believe the lower mortality rate can be attributed to better detection and treatment for AF, which, according to the British Heart Foundation, affects more than 1.5 million people in the UK.

But the findings reveal significant health inequalities, showing that the most socioeconomically deprived patients were 22% more likely to die from AF-related conditions than people from the most affluent group.

Additionally, patients are now more likely to be diagnosed with coexisting health conditions such as diabetes, cancer and chronic kidney disease, which have greater health implications for them than AF.

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Senior author Chris Gale, Professor of Cardiovascular Medicine, Honorary Consultant Cardiologist, and Co-Director of the Leeds Institute for Data Analytics at the University of Leeds said: "Atrial fibrillation is a common and often undetected heart rhythm disorder that increases the risk of stroke. Advances in health care have now reduced the chance of having a stroke related to AF, and from dying as result of it, if AF is detected and treated.

"However, our study also reveals important disparities in care associated with deprivation and the co-existence of other illnesses. Proactively diagnosing and treating AF in these groups will likely further reduce death and disability from cardiovascular disease. Equally, for many people, AF is a marker of co-existent disease -- identifying and treating these additional disease states could further improve outcome for people with AF."

The team is now calling for randomised clinical trials to determine whether the earlier identification and treatment of AF and associated co-morbidities could effectively improve cardiovascular health.

Data analysis

The research examined data from electronic health records of 72,412 patients from a representative sample of the UK population, who had been diagnosed with AF between 2001 and 2017. The team assessed the health outcomes in patients in the first year after their AF diagnosis, and analysed changes in cause-specific mortality and hospitalisation over time and by sex, age, socioeconomic status and diagnostic care setting.

The average patient was aged 75.6. Some 48.2% of patients were women, and 61.8% had three or more comorbidities.

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Over the study period, coexisting health concerns became more common, with almost 70% of newly diagnosed AF patients also having at least three comorbidities.

Mortality rates at one year post diagnosis were investigated, as well as the number of hospital admissions with an overnight stay within 1 year of diagnosis.

Over the study period, 20% of patients died from any cause within a year of being diagnosed with AF -- but this declined over time.

However the researchers found that deaths due to cardiovascular and cerebrovascular events (strokes) more than halved over the study period. Cardiovascular deaths declined from 7.3% in 2001/02 to 3% in 2016/2017, while cerebrovascular deaths declined from 2.6% to 1.1%.

The researchers say that the lower rates of cardiovascular deaths among AF patients in the study may be partly explained by improvements in strategies to prevent heart disease, and by changes in clinical practice that could lead to people being diagnosed earlier.

By contrast, there was an increase in mortality rates from mental and neurological disorders, from 2.5% in 2001/02 to 10.1% in 2016/17. Of these deaths, 87.2% were caused by dementia, Alzheimer's disease and Parkinson's disease. The research team say that while this could be partly due to greater awareness

of dementia, it also strengthens the evidence that the relationship between AF and dementia is a pressing research priority.

Other findings include:

• Hospitalisation is common within a year of AF diagnosis, with almost two further admissions experienced by patients

• Hospitalisation rates have increased by 17% due to increasing admissions from non-cardio/cerebrovascular causes, especially in older patients

• Hospitalisation for cardiovascular and cerebrovascular causes have decreased by 38% and 28%, respectively, but for non-cardio/cerebrovascular causes hospitalisation has increased by 42%

• Older people have experienced the greatest rise in hospitalisation, with those aged 80 years or more experiencing a 39% rise in hospitalisation within a year of AF diagnosis

Health inequalities

Professor Gale said: "Patients diagnosed in hospital or from the most deprived group had worse outcomes compared with those diagnosed in the community or from the most affluent group.

"Although increased burden of comorbidities might partly explain the increased frequency of death in these groups, the persisting difference after full adjustment for these factors suggests other social and health-care factors might also contribute.

"Our previous research showed that the most deprived individuals in the UK experience an AF diagnosis at a younger age than the most affluent individuals. This discrepancy in outcomes warrants targeted strategies and healthcare resource planning."

Lead author Jianhua Wu, Professor of Biostatistics and Health Data Science in the Queen Mary University of London's Wolfson Institute of Population Health said: "AF is one of the most prevalent heart conditions in the UK and as such it is crucial that we understand whether or not the current management of the condition is successful. Our findings provide vital evidence about the effectiveness of treatments for this condition, while also showing that other conditions are becoming more prevalent among AF patients -- potentially providing avenues for exploration of more targeted treatments."

Tiny magnetic beads produce an optical signal that could be used to quickly detect pathogens

 Getting results from a blood test can take anywhere from one day to a week, depending on what a test is targeting. The same goes for tests of water pollution and food contamination. And in most cases, the wait time has to do with time-consuming steps in sample processing and analysis.

Now, MIT engineers have identified a new optical signature in a widely used class of magnetic beads, which could be used to quickly detect contaminants in a variety of diagnostic tests. For example, the team showed the signature could be used to detect signs of the food contaminant Salmonella.

The so-called Dynabeads are microscopic magnetic beads that can be coated with antibodies that bind to target molecules, such as a specific pathogen. Dynabeads are typically used in experiments in which they are mixed into solutions to capture molecules of interest. But from there, scientists have to take additional, time-consuming steps to confirm that the molecules are indeed present and bound to the beads.

The MIT team found a faster way to confirm the presence of Dynabead-bound pathogens, using optics, specifically, Raman spectroscopy. This optical technique identifies specific molecules based on their "Raman signature," or the unique way in which a molecule scatters light.

The researchers found that Dynabeads have an unusually strong Raman signature that can be easily detected, much like a fluorescent tag. This signature, they found, can act as a "reporter." If detected, the signal can serve as a quick confirmation, within less than an hour, that a target pathogen is indeed present in a given sample. The team is currently working to develop a portable device for quickly detecting a range of bacterial pathogens, and has reported their results today in a special issue of the Journal of Raman Spectroscopy.

"This technique would be useful in a situation where a doctor is trying to narrow down the source of an infection in order to better inform antibiotic prescription, as well as for the detection of known pathogens in food and water," says study co-author Marissa McDonald, a graduate student in the Harvard-MIT Program in Health Sciences and Technology. "Additionally, we hope this approach will eventually lead to expanded access to advanced diagnostics in resource-limited environments."

Study co-authors at MIT include Postdoctoral Associate Jongwan Lee; Visiting Scholar Nikiwe Mhlanga; Research Scientist Jeon Woong Kang; Tata Professor Rohit Karnik, who is also the associate director of the Abdul Latif Jameel Water and Food Systems Lab; and Assistant Professor Loza Tadesse of the Department of Mechanical Engineering.

Oil and water

Looking for diseased cells and pathogens in fluid samples is an exercise in patience.

"It's kind of a needle-in-a-haystack problem," Tadesse says.

The numbers present are so small that they must be grown in controlled environments to sufficient numbers, and their cultures stained, then studied under a microscope. The entire process can take several days to a week to yield a confident positive or negative result.

Both Karnik and Tadesse's labs have independently been developing techniques to speed up various parts of the pathogen testing process and make the process portable, using Dynabeads.

Dynabeads are commercially available microscopic beads made from a magnetic iron core and a polymer shell that can be coated with antibodies. The surface antibodies act as hooks to bind specific target molecules. When mixed with a fluid, such as a vial of blood or water, any molecules present will glom onto the Dynabeads. Using a magnet, scientists can gently coax the beads to the bottom of a vial and filter them out of a solution. Karnik's lab is investigating ways to then further separate the beads into those that are bound to a target molecule, and those that are not. "Still, the challenge is, how do we know that we have what we're looking for?" Tadesse says.

The beads themselves are not visible by eye. That's where Tadesse's work comes in. Her lab uses Raman spectroscopy as a way to "fingerprint" pathogens. She has found that different cell types scatter light in unique ways that can be used as a signature to identify them.

In the team's new work, she and her colleagues found that Dynabeads also have a unique and strong Raman signature that can act as a surprisingly clear beacon.

"We were initially seeking to identify the signatures of bacteria, but the signature of the Dynabeads was actually very strong," Tadesse says. "We realized this signal could be a means of reporting to you whether you have that bacteria or not."

Testing beacon

As a practical demonstration, the researchers mixed Dynabeads into vials of water contaminated with Salmonella. They then magnetically isolated these beads onto microscope slides and measured the way light scattered through the fluid when exposed to laser light. Within half a second, they quickly detected the Dynabeads' Raman signature -- a confirmation that bound Dynabeads, and by inference, Salmonella, were present in the fluid.

"This is something that can be used to rapidly give a positive or negative answer: Is there a contaminant or not?" Tadesse says. "Because even a handful of pathogens can cause clinical symptoms."

The team's new technique is significantly faster than conventional methods and uses elements that could be adapted into smaller, more portable forms -- a goal that the researchers are currently working toward. The approach is also highly versatile.

"Salmonella is the proof of concept," Tadesse says. "You could purchase Dynabeads with E.coli antibodies, and the same thing would happen: It would bind to the bacteria, and we'd be able to detect the Dynabead signature because the signal is super strong."

The team is particularly keen to apply the test to conditions such as sepsis, where time is of the essence, and where pathogens that trigger the condition are not rapidly detected using conventional lab tests.

"There are a lot cases, like in sepsis, where pathogenic cells cannot always be grown on a plate," says Lee, a member of Karnik's lab. "In that case, our technique could rapidly detect these pathogens."

This research was supported, in part, by the MIT Laser Biomedical Research Center, the National Cancer Institute, and the Abdul Latif Jameel Water and Food Systems Lab at MIT.

How being in space impairs astronauts' immune system

 A new study led by researchers at Karolinska Institutet in Sweden has examined how T cells of the immune system are affected by weightlessness. The results, which are published in the journal Science Advances, could explain why astronauts' T cells become less active and less effective at fighting infection.

The next steps in the exploration of space are human missions to the moon and to Mars. Space is an extremely hostile environment that poses threats to human health. One such threat is changes to the immune system that occur in astronauts while in space and that persist after their return to Earth. This immune deficiency can leave them more vulnerable to infection and lead to the reactivation of latent viruses in the body.

"If astronauts are to be able to undergo safe space missions, we need to understand how their immune systems are affected and try to find ways to counter harmful changes to it," says study leader Lisa Westerberg, principal researcher at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet. "We've now been able to investigate what happens to T cells, which are a key component of the immune system, when exposed to weightless conditions."

In the study, the researchers have tried to simulate weightlessness in space using a method called dry immersion. This involves a custom-made waterbed that tricks the body into thinking it is in a weightless state. The researchers examined T cells in the blood of eight healthy individuals for three weeks of exposure to simulated weightlessness. Blood analyses were performed before the experiment started, at 7, 14 and 21 days after the start, and at 7 days after the experiment ended.

They found that the T cells significantly changed their gene expression -- that is to say, which genes were active and which were not -- after 7 and 14 days of weightlessness and that the cells became more immature in their genetic programme. The greatest effect was seen after 14 days.

"The T cells began to resemble more so-called naïve T cells, which have not yet encountered any intruders. This could mean that they take longer to be activated and thus become less effective at fighting tumour cells and infections. Our results can pave the way for new treatments that reverse these changes to the immune cells' genetic programme," says Carlos Gallardo Dodd, PhD student at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet and shared first author with researchers Christian Oertlin and Julien Record at the same department.

After 21 days, the T cells had "adapted" their gene expression to weightlessness so that it had almost returned to normal, but analyses carried out seven days after the experiment ended showed that the cells had regained some of the changes.

The researchers now plan to use Esrange Space Centre's sounding rocket platform in Kiruna, Sweden, to study how T cells behave in weightless conditions and how their function is affected.

The study was financed by the Swedish National Space Agency, the Swedish Research Council and Karolinska Institutet and was conducted in close collaboration with Claudia Kutter's research group at Karolinska Institutet/SciLifeLab and collaboration partners at IBMP Moscow and New York University Abu Dhabi. There are no reported conflicts of interest.

Unlocking the secrets of cell antennas

 The non-specific lethal (NSL) complex is a chromatin-associated factor that has been shown to regulate the expression of thousands of genes in both fruit flies and mammals. Abrogation of the NSL genes leads to the death of the organism, and this phenotype gives rise to this complex's curious name. Max Planck researchers have now identified the NSL complex as a "master" epigenetic regulator of intraciliary transport genes across multiple cell types and species. The study reveals that this class of genes is "turned on" by the NSL complex irrespective of whether a particular cell has cilia or not. Additionally, the researchers uncovered that this class of cilia-associated genes is in fact vitally important for the function of kidney podocytes, a highly specialized cell type that paradoxically does not carry cilia. These findings have important implications for ciliopathies and kidney disease.

Cilia are thin, eyelash-like extensions on the surface of cells. They perform a wide variety of functions, acting as mechanosensors or chemosensors, and play a crucial role in many signaling pathways. In the last few decades, the organelle has undergone a remarkable, but at the same time sinister, career transformation. It evolved from an organelle whose relevance was unclear to becoming a central player in the pathogenesis of a large group of diseases. These so-called ciliopathies are associated with a wide range of symptoms, including hearing loss, visual impairment, obesity, kidney disease, and mental disability. Different gene mutations impair cilia formation, maintenance, and function, resulting in these ciliopathies, which can sometimes be multi-organ, syndromic disorders.

The proper assembly, maintenance, and function of cilia rely on a process called "intraciliary transport." Components of the intraciliary transport system "walk" on the microtubule to deliver cargo between the cell body and the ciliary tip to ensure a constant supply of materials. Mutation of genes encoding components within the intraciliary transport machinery could lead to ciliopathies. In their recent study in the journal Science Advances, the lab of Asifa Akhtar identified the NSL complex as a transcriptional regulator of genes known for their roles in the intraciliary transport system of cilia across multiple cell types.

The NSL complex enables intraciliary transport

The NSL complex is a potent epigenetic modifier that regulates thousands of genes in fruit flies, mice, and humans. However, most of the functions of the NSL complex remain mysterious and have only recently begun to be elucidated. "Previous research from our lab indicates that the NSL complex controls many pathways critical for organismal development and cellular homeostasis," says Asifa Akhtar, Director at the MPI of Immunobiology and Epigenetics in Freiburg.

The complex comprises several proteins and is a histone acetyltransferase (HAT) complex that prepares the genes for activation. "Think of gene regulation as a team effort with different players. One important player is the NSL complex. It puts special marks on the histone proteins on which the DNA is wrapped around in the nucleus, like putting up green flags. These flags tell other regulators to switch on specific genes. We now found that the NSL complex does exactly this for a group of genes linked to moving materials within cilia," says Tsz Hong Tsang, the first author of the study.

Without components of the NSL complex, the cell cannot build a cilium

The intraciliary transport system is essential because it is needed to build a functional cilium. The cell uses the intraciliary transport system to move material from the cilium base to the growing tip -- similar to building a tower. In the study, the researchers used mouse cells to determine the functional consequences of the loss of the NSL complex in the cells.

They found that fibroblast cells lacking the NSL complex protein KANSL2 could not activate the transport genes nor assemble cilia. "As cilia are the sensory and signaling hubs for cells, loss of KANSL2 leads to the inability of cells to activate the sonic hedgehog signaling pathway, which plays important roles in the regulation of embryonic development, cell differentiation, and maintenance of adult tissues as well as cancer," says Asifa Akhtar.

Although tiny protrusions, these sensory organelles are incredibly important to cells. Ciliopathies, which affect organs as diverse as the kidney, liver, eye, ear, and central nervous system, remain challenging for biological and clinical studies. The researchers at the Max Planck Institute in Freiburg hope that their analysis of the role of the NSL complex has provided important insights into the regulation of these organelles and the genes associated with them, thus contributing to human health.

Consequences of NSL loss in non-ciliated cells

Cilia are found in most cell types in the human body. This explains why ciliopathies can affect so many different organs and tissues, but there are also cells that are not ciliated. One of the cell types that do not have cilia is mature glomerular podocytes, which are special filtration cells in the kidney. "Interestingly, we found that podocytes also express these intraciliary transport genes that are regulated by the NSL complex. So, we wondered what would happen if they are unable to switch on these genes," says Tsz Hong Tsang.

The researchers found that in non-ciliated mouse podocytes, the loss of KANSL2 leads to changes in microtubule dynamics in the cells. Microtubules are cytoskeletal components responsible for the mechanical stabilization of the cell and intracellular transport between different organelles. While lacking cilia, mature podocytes have specialized cell processes extending from the cell body called primary and secondary processes, whose functions rely heavily on cytoskeletal components. Although apparently milder than the defect in ciliated cells, the Akhtar lab found that the cytoskeletal defects are likely the cause of severe glomerulopathy and kidney failure observed in mice lacking the NSL complex. These and other extraciliary functions of intraciliary transport genes may help explain the complexity of symptoms presented by ciliopathies.

Scientists solve mystery of why thousands of octopus migrate to deep-sea thermal springs

 In 2018, researchers from NOAA's Monterey Bay National Marine Sanctuary and Nautilus Live observed thousands of octopus nesting on the deep seafloor off the Central California coast. The discovery of the "Octopus Garden" captured the curiosity of millions of people around the world, including MBARI scientists. For three years, MBARI and collaborators used high-tech tools to monitor the Octopus Garden and learn exactly why this site is so attractive for deep-sea octopus.

In a new study published today in Science Advances, a team of researchers from MBARI, NOAA's Monterey Bay National Marine Sanctuary, Moss Landing Marine Laboratories, the University of Alaska Fairbanks, the University of New Hampshire, and the Field Museum confirmed that deep-sea octopus migrate to the Octopus Garden to mate and nest. The Octopus Garden is one of a handful of known deep-sea octopus nurseries. At this nursery, warmth from deep-sea thermal springs accelerates the development of octopus eggs. Scientists believe the shorter brooding period increases a hatchling octopus' odds for survival. The Octopus Garden is the largest known aggregation of octopus on the planet -- researchers counted more than 6,000 octopus in a portion of the site and expect there may be 20,000 or more at this nursery.

"Thanks to MBARI's advanced marine technology and our partnership with other local researchers, we were able to observe the Octopus Garden in tremendous detail, which helped us discover why so many deep-sea octopus gather there. These findings can help us understand and protect other unique deep-sea habitats from climate impacts and other threats," said MBARI Senior Scientist Jim Barry, lead author of the new study.

The Octopus Garden is located 3,200 meters (10,500 feet, or about two miles) below the ocean's surface on a small hill near the base of Davidson Seamount, an extinct underwater volcano 130 kilometers (80 miles) southwest of Monterey, California. The site is full of Muusoctopus robustus -- a species MBARI researchers nicknamed the pearl octopus because from a distance, nesting individuals look like opalescent pearls on the seafloor.

Over the course of 14 dives with MBARI's remotely operated vehicle (ROV) Doc Ricketts, the research team learned why such large numbers of pearl octopus are attracted to this location. The presence of adult male and female octopus, developing eggs, and octopus hatchlings indicated that the site is used exclusively for reproduction. The team did not observe any intermediate-sized individuals or any evidence of feeding. Pearl octopus gather at this site solely to mate and nest.

When researchers from NOAA and Nautilus Live first discovered the Octopus Garden, they observed "shimmering" waters. This phenomenon occurs when warm and cool waters mix, suggesting the region had previously unknown thermal springs. Further investigation by MBARI researchers and their collaborators confirmed octopus nests are clustered in crevices bathed by hydrothermal springs where warmer waters flow from the seafloor.

The ambient water temperature at 3,200 meters (10,500 feet) deep is 1.6 degrees Celsius (about 35 degrees Fahrenheit). However, the water temperature within the cracks and crevices at the Octopus Garden reaches nearly 11 degrees Celsius (about 51 degrees Fahrenheit).

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Octopuses are ectotherms, or cold-blooded animals. The frigid temperatures of the deep sea slow their metabolism as well as their rate of embryonic development. Most deep-sea octopuses have very long incubation periods compared to their relatives inhabiting warmer shallow seas. Past experiments have measured egg incubation time for a number of octopus species in habitats and locations around the world. Comparing those egg incubation times clearly demonstrates how temperature affects the rate of embryo development -- the colder the water, the slower the embryos grow.

At the near-freezing temperatures of the abyss, researchers expected pearl octopus eggs to take five to eight years, if not longer, to hatch. A 4K camera on MBARI's ROV Doc Ricketts provided a close-up look at nesting mothers. MBARI researchers and their collaborators used the scars and other distinguishing features of individual octopus moms to monitor the development of their broods. Surprisingly, the eggs hatched in less than two years. Warmth from thermal springs increased the metabolism of female octopus and their broods, reducing the time required for incubation.

Researchers believe the shorter brood period in warmer waters greatly reduces the risk that developing octopus embryos will be injured or eaten by predators. Nesting in warmer water boosts the reproductive success of the pearl octopus, better ensuring the offspring's survival.

"The deep sea is one of the most challenging environments on Earth, yet animals have evolved clever ways to cope with frigid temperatures, perpetual darkness, and extreme pressure. Very long brooding periods increase the likelihood that a mother's eggs won't survive. By nesting at hydrothermal springs, octopus moms give their offspring a leg up," said Barry.

The massive number of octopus in one area attracts both predators and scavengers. Like most other cephalopods, pearl octopus die after they reproduce. Dead octopus at the Octopus Garden provide a feast for scavengers. A rich community of invertebrates lives alongside the nesting females, undoubtedly benefiting from unhatched eggs, vulnerable hatchlings, or adult octopus that have died.

Davidson Seamount and its Octopus Garden are protected as part of Monterey Bay National Marine Sanctuary. Previous MBARI expeditions to Davidson Seamount in 2002 and 2006 revealed the stunning community of life on its rocky slopes. MBARI's images and video of beautiful deep-sea corals, vibrant sponges, and curious fishes engaged and inspired audiences worldwide. Ocean champions spoke up to protect this unique, and still untouched, ocean wilderness. In 2008, resource managers expanded the Monterey Bay National Marine Sanctuary to include Davidson Seamount.

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"Essential biological hotspots like this deep-sea nursery need to be protected," said Barry. "Climate change, fishing, and mining threaten the deep sea. Protecting the unique environments where deep-sea animals gather to feed or reproduce is critical, and MBARI's research is providing the information that resource managers need for decision-making."

This work is funded as part of the David and Lucile Packard Foundation's long-term support of MBARI's ocean research and technology.

Background

For more than two decades, researchers from MBARI and NOAA have collaborated to study Davidson Seamount. Since the first expedition to the seamount in 2002, NOAA has leveraged MBARI expertise in marine geology and benthic biology and ecology to develop a comprehensive research program that aims to understand the unique community of life on and around Davidson Seamount. Now, Davidson Seamount is considered one of the best-studied and well-protected seamounts in the world.

In October 2018, a team of researchers from NOAA, the Ocean Exploration Trust, and collaborators made an expedition to Davidson Seamount aboard the E/V Nautilus. At the suggestion of MBARI geologists and NOAA researchers, the Nautilus Live team decided to expand their exploration from the top of the seamount to its surrounding foothills. The researchers discovered thousands of octopus aggregated around a rocky ridge adjacent to the towering seamount.

Most of the octopus were oriented upside down, inverting their arms and folding them around their bodies. This posture was an indication of pearl octopus (Muusoctopus robustus) mothers protecting, or brooding, their eggs. The pearl octopus is a pale purple species about the size of a grapefruit that occurs in the northeastern Pacific Ocean from Oregon to Baja California. MBARI has observed this species at depths of 2,300 to 3,600 meters (7,500 to 11,800 feet).

MBARI researchers and their collaborators deployed a suite of advanced scientific instruments developed by MBARI engineers to better understand the Octopus Garden.

"The expertise of the MBARI team -- the engineers, pilots of our submersible vehicles, and crew of our research vessels -- was integral to studying this hotspot of life two miles below the surface. We leveraged decades of experience in deep-sea exploration to develop and deploy instruments to study the Octopus Garden without disturbing the nesting mothers," said Barry.

MBARI's ROV Doc Ricketts recorded high-definition and 4K video of the brooding pearl octopus and their neighbors. MBARI's skilled submersible pilots maneuvered the ROV close to brooding pearl octopus to deploy instruments to measure the environmental conditions within their nests, including temperature and oxygen levels, and to film mothers and their eggs up close in ultra-high definition resolution. A stereoscopic camera allowed MBARI engineers to visualize sites within the Octopus Garden in 3D. The team also launched one of MBARI's autonomous underwater vehicles to map the Octopus Garden at meter-scale resolution.

MBARI engineers outfitted the ROV Doc Ricketts with an innovative, custom-built sensor suite, the Low-Altitude Survey System (LASS), to see the Octopus Garden in even greater detail.

The LASS gathered detailed bathymetry information to help researchers characterize the seafloor habitat at centimeter-scale resolution. The LASS also took high-resolution photographs of the Octopus Garden. Researchers assembled these photographs into a photomosaic to count the number of nests within this deep-sea nursery. They documented 5,718 octopus within a 2.5-hectare (6.2-acre) area at the center of the Octopus Garden. The team estimated the total population of the 333-hectare (823-acre) hillock could easily exceed 20,000 individuals.

A time-lapse camera collected long-term observations of the octopus' behavior and changes in the community over a period of more than six months, allowing researchers to keep watch on the octopus nursery between research expeditions. The camera recorded an image every 20 minutes and amassed a trove of more than 12,200 images from March 2022 to August 2022. These photographs revealed various activities and behaviors of octopus, their predators, and local scavengers.

Both male and female pearl octopus migrate to the Octopus Garden. Females search for a warm nesting spot to deposit a clutch of approximately 60 elongate, sausage-shaped eggs. When brooding, mothers cover their eggs with their body and protect them from predators that creep too close. She lives off food reserves from her own tissues while tending to her developing eggs.

The transformation from egg to hatchling is not easy. In addition to going through development successfully, embryos must avoid injury, predation, infection, and other external sources of mortality. Maternal care protects them from most external risks, but a shorter brooding period generally allows more eggs to survive.

As is typical of cephalopods, male and female pearl octopus die after reproducing -- the Octopus Garden will be their final resting spot. Most females live until their eggs have hatched. Sometimes, however, a mother octopus runs out of energy and dies before her eggs complete their development, exposing the developing eggs to greater risk.

The time-lapse camera revealed that nesting mothers push aside the carcasses of dead octopus. Food is scarce in the deep sea and nothing goes to waste. Larger scavengers like rattail fishes (family Macrouridae), cusk eels (family Ophidiidae), whelks, and sea anemones feast on octopus remains. Near Davidson Seamount, life on the deep seafloor depends on the rain of organic matter from above. Researchers estimated the turnover of male octopus and nesting females to calculate how much nutrition this massive aggregation provides. Biomass from dying octopus represents a substantial carbon subsidy to the local seafloor community, providing 72 percent more food than is available outside the Octopus Garden.

Many questions still remain about the Octopus Garden, including where pearl octopus go after hatching, how this octopus species became adapted to breeding in thermal springs, how adult octopus find the thermal springs, what advantage individuals breeding in these hydrothermal springs have over those that breed elsewhere, and how common hydrothermal springs are in the deep sea.

The deep sea is not immune to threats like fishing, pollution, and climate change. By documenting deep-sea biodiversity and identifying hotspots of life on the ocean floor, scientists are gathering important information that resource managers can use to guide protections for this unique environment and its inhabitants.

"Technological advances in our ability to study the ocean have helped us discover and document incredible biodiversity across an array of deep-sea environments. As the imprint of human activities reaches deeper into ocean ecosystems, we need to protect not only the octopus nurseries found off California and Costa Rica, but also the many other biological treasures that remain undiscovered," emphasized Barry.

Deep-sea octopus nurseries: A new field of exploration

Researchers have documented four deep-sea octopus nurseries to date -- two off the coast of Central California and two off the coast of Costa Rica -- and are continuing to study these sites to learn more about octopus behavior.

December 2013: Discovery of first octopus nursery at Dorado Outcrop (Costa Rica) Researchers from the University of Akron, the Field Museum, and the University of Alaska Fairbanks observed an aggregation of more than 100 octopus at the Dorado Outcrop, a hydrothermal spring located approximately 160 kilometers (100 miles) off the Pacific coast of Costa Rica at a depth of 3,000 meters (9,800 feet). The team identified the octopus as a potentially undescribed species of Muusoctopus. Nearly all of the individuals were in a brooding position, however, none of the eggs that researchers observed were viable.

April 2018: Researchers publish findings from the Dorado Outcrop (Costa Rica) The team of researchers from the University of Akron, the Field Museum, and the University of Alaska Fairbanks published their observations of deep-sea octopus brooding unviable eggs at the Dorado Outcrop in Deep Sea Research Part I.

October 2018: Discovery of second octopus nursery at the Octopus Garden (Davidson Seamount, United States) During a Nautilus Live expedition with the E/V Nautilus, researchers from NOAA's Monterey Bay National Marine Sanctuary, the Ocean Exploration Trust, and collaborators observed a large aggregation of brooding octopus on a hillock approximately 12 kilometers (7.5 miles) southeast of Davidson Seamount at a depth of 3,200 meters (10,500 feet). Researchers identified the octopus as Muusoctopus robustus. A second visit by researchers from NOAA and the Woods Hole Oceanographic Institution (WHOI) in March 2019 confirmed the presence of warm hydrothermal springs at this site. The expedition team also confirmed that the octopus were brooding viable eggs and observed baby octopus hatching from the eggs.

April 2019: First MBARI expedition to Octopus Garden (Davidson Seamount, United States) MBARI researchers made their first visit to the Octopus Garden as part of the 2019 Seafloor Ecology expedition. Along with collaborators, they visited the site 14 times with the R/V Western Flyer between April 2019 and August 2022. Additionally, MBARI researchers visited the Octopus Garden with the R/V Rachel Carson in February 2022 to launch a mapping autonomous underwater vehicle and create meter-scale maps of the site.

October 2019: Discovery of third octopus nursery at Octocone (Davidson Seamount, United States) During a Nautilus Live expedition with the E/V Nautilus, researchers from NOAA, the Ocean Exploration Trust, and collaborators observed a second aggregation of brooding octopus on a volcanic cone to the east of Davidson Seamount. This site is approximately 17 kilometers (10.5 miles) northeast of the Octopus Garden. Researchers identified the octopus as Muusoctopus robustus. The octopus were confirmed to be brooding viable eggs.

June 2023: Discovery of fourth octopus nursery (Costa Rica) During a Schmidt Ocean Institute expedition with the R/V Falkor (too), researchers from the Bigelow Laboratory for Ocean Sciences and the University of Costa Rica observed a previously unknown octopus nursery near an unexplored and still-unnamed seamount off the Pacific coast of Costa Rica. Upon returning to the nearby Dorado Outcrop, the team also observed octopus brooding viable eggs, confirming this location is indeed an active octopus nursery. Both Costa Rican nurseries host a potentially undescribed species of Muusoctopus.

August 2023: MBARI researchers publish findings from the Octopus Garden (Davidson Seamount, United States) MBARI researchers and their collaborators from NOAA, Moss Landing Marine Laboratories, the University of Alaska Fairbanks, the University of New Hampshire, and the Field Museum published their research on brooding pearl octopus in Science Advances, confirming that deep-sea octopus migrate to the Octopus Garden to mate and nest.

Malaysian rock art found to depict elite -- Indigenous conflict

 A team of researchers led by the Griffith Centre for Social and Cultural Research in collaboration with The Sarawak Museum Department have become the first to date drawings of Gua Sireh Cave in Sarawak, uncovering a sad story of conflict in the process.

The limestone cave of Gua Sireh in western Sarawak (Malaysian Borneo) is famous for the hundreds of charcoal drawings lining the walls of its main chambers, attracting hundreds of visitors each year.

Approximately 55km southeast of Sarawak's Capital, Kuching, the site is managed by the Bidayuh (local Indigenous peoples) in collaboration with The Sarawak Museum Department, with the drawings depicting Indigenous resistance to frontier violence in the 1600s and 1800s AD.

Radiocarbon ages for the drawings date them between 280 and 120 cal BP (AD 1670 to 1830), corresponding with a period of increasing conflict in the region when the Malay elites controlling the region exacted heavy tolls on Indigenous hill tribes, including the Bidayuh.

To the best of the team's knowledge, these radiocarbon dates are the first chronometric age determinations for Malaysian rock art.

Study co-lead, Dr Jillian Huntley said the first step was establishing what had been used to make the drawings.

"We wanted to confirm the images were drawn with charcoal, as there are a limited number of substances you can actually radiocarbon date," she said.

"We were looking at the decay isotopes of carbon, which meant the material had to be carbon bearing, and our analyses (with collaborator Dr Emilie Dotte-Sarout at University of Western Australia) determined charcoal from different species of bamboo had been used.

"Being drawn on limestone, they're remarkably well preserved."

The art at Gua Sireh is part of a wider distribution of black drawings found from the Philippines through central Island Southeast Asia across Borneo and Sulawesi to Peninsular Malaysia. They are thought to be associated with the diaspora of Austronesian speaking peoples.

Previous dating work, also led by the Griffith Centre for Social and Cultural Research, has established similar drawings in the Philippines were made as early as ~3500 cal BP and ~1500 cal BP in southern Sulawesi.

"Black drawings in the region have been made for thousands of years," Dr Huntley said.

"Our work at Gua Sireh indicates this art form was used up to the recent past to record Indigenous peoples' experiences of colonisation and territorial violence."

Co-lead Distinguished Professor Paul Tacon said the team knew from previous work in the region that northwest Borneo's rock art (the Malaysian states of Sabah and Sarawak) is dominated by drawings of people, animals, ships and abstract geometric/linear design.

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"At Gua Sireh, people are drawn wearing headdresses -- some armed with shields, knives and spears, in scenes showing activities such as hunting, butchering, fishing, fighting and dancing," he said.

"We had clues about their age based on subjects such as introduced animals, but we really didn't know how old they were, so it was difficult to interpret what they might mean."

Bidayuh descendant and curator at The Sarawak Museum Department Mr Mohammad Sherman Sauffi William said understanding of the dates had been informed by the oral histories of the Bidayuh who have continuing custodial responsibilities over the site today.

"The Bidayuh recall Gua Sireh's use as a refuge during territorial violence in the early 1800s when a very harsh Malay Chief had demanded they hand over their children," he said.

"They refused and retreated to Gua Sireh, where they initially held off a force of 300 armed men trying to enter the cave from the valley about 60 meters below.

"Suffering some losses (two Bidayuh were shot and seven taken prisoner/enslaved), they saved their children when most of the tribe escaped through a passageway at the back of the largest entrance chamber which leads hundreds of meters through the Gunung Nambi limestone hill.

"The figures were drawn holding distinctive weapons such as a Pandat which was used exclusively for fighting or protection, as well two short-bladed Parang Ilang, the main weapons used during warfare that marked the first decades of white rule in Borneo."

2023 Global Heat Wave: July brought the hottest three weeks observed so far

 The first three weeks of July 2023 have been the hottest global three-week period so far. In the summer months of 2023, twice as many people in Germany were exposed to daily temperatures of 35 degrees and higher than the average from 1980 to 1999. This is obvious from a study published recently by Karlsruhe Institute of Technology (KIT). Researchers from KIT's Center for Disaster Management and Risk Reduction Technology (CEDIM) report that the European population's exposure to heat was highest in Italy.

In the summer of the year 2023, several hot spells of variable length and intensity occurred partly simultaneously in different regions of the northern hemisphere. In their "Untersuchung der globalen Hitzewelle im Jahr 2023" (investigation of the global heat wave in 2023), researchers of the Forensic Disaster Analysis (FDA) Task Force Group of KIT's CEDIM analyzed the record temperatures reached and the population's exposure to heat.

Ocean Surface Temperatures in June 2023 Were as High as Never Before since records began

In some regions, previous all-time record temperatures were exceeded by far, in other areas new daily or monthly records were recorded. In June 2023, global mean ocean surface temperatures were as high as never before. As regards the Earth's surface, including landmass, June 2023 has been the warmest June since 1850. On a global scale, the first three weeks of July 2023 were the hottest three-week period ever. The daily record, a global surface temperature of 17.08 degrees Celsius was reached on July 6, closely followed by July 5 and 7 with 17.07 degrees Celsius each. In July 2023, extreme temperatures and new country records -- official confirmation by the World Meteorological Organization (WMO) is still pending -were reached in the Mediterranean countries, including North Africa and the Middle East. Record-breaking temperatures were also reported by the USA, Canada, and China.

"For a big temperature anomaly to develop over a longer term, a long-lasting and unusually large-scale flow pattern is required," says Dr. Andreas Schäfer from the FDA Task Force Group of CEDIM. Pressure distribution in the middle troposphere at about 5.5 kilometers altitude plays an important role, as it influences upper airflow and the associated air mass transport. "In July 2023, extraordinarily persistent high-pressure areas prevailed in the regions affected by the high temperatures. Here, descending air masses contributed significantly to warming and the local development of the heat wave," Schäfer says.

The researchers also studied the population's exposure to heat. In Germany, about seven million people were exposed to daily maximum temperatures higher than 25 degrees Celsius. These were about 40 percent more than the average number of the years 1980 to 1999. The number of persons exposed to daily temperatures of 35 degrees Celsius and higher even doubled to about 206,000. Compared to previous decades, heat exposure during the summer months was also much higher in Italy, Greece, Spain, the USA, China, and India.

Paper drinking straws may be harmful and may not be better for the environment than plastic versions

 "Eco-friendly" paper drinking straws contain long-lasting and potentially toxic chemicals, a new study has concluded.

In the first analysis of its kind in Europe, and only the second in the world, Belgian researchers tested 39 brands of straws for the group of synthetic chemicals known as poly- and perfluoroalkyl substances (PFAS).

PFAS were found in the majority of the straws tested and were most common in those made from paper and bamboo, the study, published in the peer-reviewed journal Food Additives and Contaminants, found.

PFAS are used to make everyday products, from outdoor clothing to non-stick pans, resistant to water, heat and stains. They are, however, potentially harmful to people, wildlife and the environment.

They break down very slowly over time and can persist over thousands of years in the environment, a property that has led to them being known as "forever chemicals."

They have been associated with a number of health problems, including lower response to vaccines, lower birth weight, thyroid disease, increased cholesterol levels, liver damage, kidney cancer and testicular cancer.

"Straws made from plant-based materials, such as paper and bamboo, are often advertised as being more sustainable and eco-friendly than those made from plastic," says researcher Dr Thimo Groffen, an environmental scientist at the University of Antwerp, who is involved in this study.

"However, the presence of PFAS in these straws means that's not necessarily true."

A growing number of countries, including the UK and Belgium, have banned sale of single-use plastic products, including drinking straws, and plant-based versions have become popular alternatives.

A recent study found PFAS in plant-based drinking straws in the US. Dr Groffen and colleagues wanted to find out if the same was true of those on sale in Belgium.

To explore this further, the research team purchased 39 different brands of drinking straw made from five materials -- paper, bamboo, glass, stainless steel and plastic.

The straws, which were mainly obtained from shops, supermarkets and fast-food restaurants, then underwent two rounds of testing for PFAS.

The majority of the brands (27/39, 69%) contained PFAS, with 18 different PFAS detected in total.

The paper straws were most likely to contain PFAS, with the chemicals detected in 18/20 (90%) of the brands tested. PFAS were also detected in 4/5 (80%) brands of bamboo straw, 3/4 (75%) of the plastic straw brands and 2/5 (40%) brands of glass straw. They were not detected in any of the five types of steel straw tested.

The most commonly found PFAS, perfluorooctanoic acid (PFOA), has been banned globally since 2020.

Also detected were trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMS), "ultra-short chain" PFAS which are highly water soluble and so might leach out of straws into drinks.

The PFAS concentrations were low and, bearing in mind that most people tend to only use straws occasionally, pose a limited risk to human health. However, PFAS can remain in the body for many years and concentrations can build up over time.

"Small amounts of PFAS, while not harmful in themselves, can add to the chemical load already present in the body," says Dr Groffen.

It isn't known whether the PFAS were added to the straws by the manufacturers for waterproofing or whether were the result of contamination. Potential sources of contamination include the soil the plant-based materials were grown in and the water used in the manufacturing process.

However, the presence of the chemicals in almost every brand of paper straw means it is likely that it was, in some cases, being used as a water-repellent coating, say the researchers.

The study's other limitations include not looking at whether the PFAS would leach out of the straws into liquids.

Dr Groffen concludes: "The presence of PFAS in paper and bamboo straws shows they are not necessarily biodegradable.

"We did not detect any PFAS in stainless steel straws, so I would advise consumers to use this type of straw -- or just avoid using straws at all