To achieve causal evidence, the researchers from the Lise Meitner Group for Environmental Neuroscience examined brain activity in regions involved in stress processing in 63 healthy volunteers before and after a one-hour walk in Grunewald forest or a shopping street with traffic in Berlin using functional magnetic resonance imaging (fMRI). The results of the study revealed that activity in the amygdala decreased after the walk in nature, suggesting that nature elicits beneficial effects on brain regions related to stress.

“The results support the previously assumed positive relationship between nature and brain health, but this is the first study to prove the causal link. Interestingly, the brain activity after the urban walk in these regions remained stable and did not show increases, which argues against a commonly held view that urban exposure causes additional stress,” explains Simone Kühn, head of the Lise Meitner Group for Environmental Neuroscience.

The authors show that nature has a positive impact on brain regions involved in stress processing and that it can already be observed after a one-hour walk. This contributes to the understanding of how our physical living environment affects brain and mental health. Even a short exposure to nature decreases amygdala activity, suggesting that a walk in nature could serve as a preventive measure against developing mental health problems and buffering the potentially disadvantageous impact of the city on the brain.

The results go in line with a previous study (2017, Scientific Reports) which showed that city dwellers who lived close to the forest had a physiologically healthier amygdala structure and were therefore presumably better able to cope with stress. This new study again confirms the importance for urban design policies to create more accessible green areas in cities in order to enhance citizens’ mental health and well-being.

In order to investigate benedicial effects of nature in different populations and age groups, the researchers are currently working on a study examining how a one-hour walk in natural versus urban environments impacts stress in mothers and their babies.

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A team led by the University of Exeter tested bee behaviour and built bee’s-eye-view simulations to work out how they see flowers.

Honeybees have low-resolution vision (about 100 times lower than human vision), so they can only see a flower’s pattern clearly when they are within few centimetres.

However, the new study shows bees can very effectively distinguish between different flowers by using a combination of colour and pattern.

In a series of tests, bees rarely ignored pattern — suggesting colour alone does not lead them to flowers.

This may help to explain why some colours that are visible to bees are rarely produced by flowers in nature.

“We analysed a large amount of data on plants and bee behaviour,” said Professor Natalie Hempel de Ibarra, from Exeter’s Centre for Research in Animal Behaviour.

“By training and testing bees using artificial patterns of shape and colour, we found they relied flexibly on their ability to see both of these elements.

“Showing how insects see colour and learn colour patterns is important to understand how pollinators may, or may not, create evolutionary ‘pressures’ on the colours and patterns that flowers have evolved.

“Our findings suggest that flowers don’t need to evolve too many different petal colours, because they can use patterns to diversify their displays so bees can tell them apart from other flowers.”

One consistent feature identified in the study is that the outside edges of flowers usually contrast strongly with the plant’s foliage — while the centre of the flower does not have such a strong contrast with the foliage colour.

This could help bees quickly identify colour differences and navigate to flowers.

While flowers may be beautiful to humans, Professor Hempel de Ibarra stressed that understanding more about bees — and the threats they face — meant we need to see the world “through the eyes of a bee and the mind of a bee.”

The research, by a team including the Free University of Berlin and the University of Auckland, was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).

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Importantly, the researchers also found that it does not appear to matter which types of fish are eaten because the essential nutrients in the fish could be protective against the mercury content of the fish. The more important factor was whether the woman ate fish or not. This contrasts with current advice warning pregnant women not to eat certain types of fish that have relatively high levels of mercury.

Although there are several studies that have considered this question, this research has looked at two contrasting studies of populations with mercury levels measured during pregnancy where the children were followed up at frequent intervals during their childhood.

The first is a study focused on a population in the Seychelles, where almost all pregnant women are fish eaters. The second study considered analyses of data from the University of Bristol’s Children of the 90s study (also known as the Avon Longitudinal Study of Parents and Children (ALSPAC)), based in a relatively industrialised area in south-west England where fish are consumed far less frequently. No summary of the findings from this study has been published before.

Although it has been known for some time that the children of women who eat fish in pregnancy are likely to benefit in various ways in regard to their eyesight and intellectual abilities, official advice has included the warning not to eat certain types of fish that have relatively high levels of mercury. As a result, there is the possibility that some women will stop eating any fish ‘to be on the safe side’.

Dr Caroline Taylor, Senior Research Fellow and co-author of the study, said: “We found that the mother’s mercury level during pregnancy is likely to have no adverse effect on the development of the child provided that the mother eats fish. If she did not eat fish, then there was some evidence that her mercury level could have a harmful effect on the child. This could be because of the benefits from the mix of essential nutrients that fish provides, including long-chain fatty acids, iodine, vitamin D and selenium.”

Professor Jean Golding, co-author and Emeritus Professor of Paediatric and Perinatal Epidemiology at the University of Bristol, said: “It is important that advisories from health professionals revise their advice warning against eating certain species of fish. There is no evidence of harm from these fish, but there is evidence from different countries that such advice can cause confusion in pregnant women. The guidance for pregnancy should highlight ‘Eat at least two portions of fish a week, one of which should be oily’ — and omit all warnings that certain fish should not be eaten.”

The current study is funded via core support for ALSPAC by the UK Medical Research Council and the UK Wellcome Trust.

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A team of Stanford scientists led by Polly Fordyce, an Institute Scholar at Sarafan ChEM-H, has developed a new method to faster and more accurately predict which antigens will lead to a strong immune response. Their approach, which was reported in Nature Methods on Sept. 5, could help scientists develop more effective cancer immunotherapies.

T cells, a class of immune cells, crawl along and squish past other cells as they patrol the body, using T cell receptors to molecularly read peptides, or short pieces of proteins — which are cradled within larger proteins called major histocompatibility complexes (pMHCs) that project from cell surfaces. Healthy host cells display an array of pMHCs that do not trigger an immune response, but once T cells recognize disease-indicating peptides, they become activated to find and kill cells bearing these foreign signatures. Understanding how T cells sensitively distinguish these antigenic peptides from host peptides to avoid mistakenly killing host cells has long been a mystery.

“A T cell can detect a single antigenic peptide amongst a sea of 10,000 or 100,000 non-antigenic peptides being displayed on cell surfaces,” said Fordyce, assistant professor of bioengineering and of genetics.

The key to selectivity is in the T cell crawl. T cells’ sliding puts stress on the bonds between receptors and peptides, and in most cases, that extra stress is enough to break that bond. But sometimes, it has the opposite effect. Chris Garcia, co-author of the study and professor of molecular and cellular physiology and of structural biology, and others had already shown that the most antigenic peptides are those whose interactions with T cell receptors grow stronger in response to sliding.

“It’s kind of like a Chinese finger trap,” said Fordyce. “When you pull a bit at the receptor-antigen interaction, the binding actually lasts longer.”

Cellular mimicry

Identifying the best antigen-receptor pairs requires simultaneously applying that sliding, or shear, force between a peptide and a T cell and measuring T cell activation, ideally thousands of times to get repeatable data for many possible peptide/T cell receptor pairs. But existing methods are time-intensive and can result in measuring only one peptide with hundreds of T cells in a day.

The study’s first author, postdoctoral scholar Yinnian Feng, developed a trick that allows the team to measure 20 unique peptides interacting with thousands of T cells in less than five hours.

To make a simplified system that mimics cells with dangling peptides, they constructed small spherical beads from a material that expands upon heating and attached a few molecules of a given peptide-studded pMHC to their surfaces. After depositing a T cell atop each bead and waiting long enough for receptors to bind to the peptides, they then very slightly heated the bead. The bead’s expansion increases the distance between tether points, and the corresponding stretching of the T cell mimics the force it would experience sliding along cells in the body. After exerting that force, the team then measured how active the T cells were.

They could do hundreds of individual experiments in parallel by using beads that are each labeled with a unique color, making it possible to track multiple different pMHCs. They took two sets of pictures tiling across each slide after each run: one set that tells them which pMHC a given bead is displaying and another that tells them how active each T cell atop that bead is. Cross-referencing those images tells them which antigens led to the strongest T cell responses.

In this demonstration of their platform, the team showed, with 21 unique peptides, that their results confirmed known activating and non-activating peptides for one T cell receptor and uncovered a previously unknown antigen that induced a strong T cell response. Working with the Garcia lab, they have also already begun to address a challenge in immunotherapy: the T cell receptors that form the highest affinity interactions with antigens in the lab are often also activated by non-antigenic peptides in the body, a dangerous side effect that leads to the killing of healthy cells. Using their technology, the team characterized T cell receptors engineered to specifically recognize tumor antigens without off-target reactivity. In future work, they plan to build libraries of over 1,000 peptides to uncover novel antigens.

They hope that this approach, which is quick and requires few cells, or an optimized form of it could one day be used to improve personalized immunotherapies.

“This platform can help improve efforts to engineer T cells that specifically target cancer cells, as well as determine which antigens are capable of potently activating a patient’s own T cells to more effectively target cancer cells,” said Fordyce.

Fordyce is a member of Stanford Bio-X, SPARK, and the Wu Tsai Neurosciences Institute, and is a Chan Zuckerberg Biohub investigator. Garcia is a member of Stanford Bio-X, the Stanford Cancer Institute, the Wu Tsai Neurosciences Institute, and a Howard Hughes Medical Institute investigator.

Xiang Zhao and Adam K. White are also authors of the paper.

The work was funded by a Stanford Bio-X Interdisciplinary Initiatives seed grant and the National Institutes of Health.

COPD, a lung disease that obstructs the airways and leads to coughing, wheezing, and shortness of breath, affects about 15 million Americans. However, millions of others who smoke or used to smoke and have some symptoms of COPD have also been prescribed bronchodilators.

“We’ve assumed these medications worked in patients who don’t meet lung function criteria for COPD, but we never checked,” said MeiLan K. Han, M.D., a principal investigator and first author of the study. “We now know these existing medications don’t work for these patients.”

The findings of the study, which was funded by the National Heart, Lung, and Blood Institute (NHLBI), were published in the New England Journal of Medicine and simultaneously presented at the European Respiratory Society International Congress.

According to scientists, the implications are significant. First, they show the importance of diagnosing lung conditions through spirometry, a lung function test Han noted is underutilized in clinical practice. Second, they show the need for new, effective therapies for patients without COPD.

Inhalers have long been the primary go-to treatment for these patients, she explained, because doctors either assume a patient has COPD, or if they don’t, that their smoking-related symptoms could be helped by the inhalers. But while tobacco smoking causes a large spectrum of lung damage, the study showed bronchodilator therapy only helps patients with enough lung damage that would result in abnormal spirometry readings.

In the 12-week, randomized, double-blinded study, which was part of the Redefining Therapy in Early COPD for the Pulmonary Trials Cooperative(RETHINC), researchers enrolled 535 adults with symptoms of COPD, ages 40-80, at one of 20 U.S. medical centers. Twice each day, study participants used an inhaler that contained either medication or a placebo.

By the end of the trial, some adults in the medication (intervention) and placebo (control) groups saw slight respiratory improvements — this could mean they coughed less, produced less phlegm, or felt less winded — which was assessed through the St. George’s Respiratory Questionnaire. However, the researchers found no significant differences between those receiving medication or placebo. They reported 56% (128 of 227) of participants who received the medication saw respiratory symptom improvements, compared to 59% (144 of 244) of those who took the placebo.

According to Han, these data underscore why we can’t continue to do what we have been doing, which is not doing spirometry and just treating patients with the same COPD medications and expect that we’re going to see improvement.

Antonello Punturieri, M.D., Ph.D., program director of NHLBI’s Chronic Obstructive Pulmonary Disease/Environment Program, said spirometry testing should be used for any patient who shows signs of COPD, airflow obstruction, or who has a history of cigarette smoking. Though spirometry readings are used during about one-third of medical visits related to COPD, roughly half of patients who would meet criteria for COPD go undiagnosed.

Helping patients quit smoking is a primary way to prevent COPD or COPD-like symptoms, the study noted. More than 30 million adults smoke, according to the Centers for Disease Control and Prevention, and many who are not diagnosed with COPD share symptoms. About one in four current or former smokers without COPD have reported having shortness of breath. In addition to encouraging smoking cessation, doctors can help patients who do not meet lung-function criteria of COPD by working with them to address any other underlying issues, such as overweight and obesity, heart failure, or other lung issues.

“In the meantime, research should be focused on finding new treatments for them,” Han explained. “The next question is, can we develop more targeted therapies for these patients who are on the milder end of the spectrum?”

“Because cough and mucus production show up prominently among these patients, we believe therapies that target mucus production in the airways may be effective,” said Prescott G. Woodruff, M.D., a principal investigator and senior author of the study.

Some of these therapies are already in development, and data from other studies may offer insight into the biological causes of excessive airway mucus. Those clues could help researchers identify additional therapies.