By dating and tracing pieces of driftwood on beaches in Svalbard, Norway’s archipelago in the Arctic Circle, scientists have determined where these fallen trees floated. Retracing the driftwood’s journey let the researchers reconstruct, for the first time, both the level of sea ice over time and the currents that propelled the driftwood-laden ice.

Borne by rivers to the ocean, fallen trees from the north’s expansive boreal forests can be frozen in sea ice and float far, but the new research showsfewer trees are making the long journey as the sea ice that carries them shrinks away.

The new study found a distinct drop in new driftwood arrivals over the last 30 years, reflecting the steep decline in sea ice coverage in a warming Arctic and provides a higher-resolution picture of past Arctic Ocean conditions than other methods allow. The study is published in the Journal of Geophysical Research: Oceans, which publishes research that advances our understanding of the ocean and its processes.

Sea ice is sensitive to climate change and is an important part of Arctic ecosystems, so understanding how ice, ocean temperatures and currents have varied together over time is necessary for predicting coming changes in the Arctic. But doing so can be elusive: Ice melts, after all. The oldest sea ice is only about four years old (and getting younger), so scientists need to turn to other records.

“This is the first time driftwood has been used to look at large-scale changes in Arctic sea ice dynamics and circulation patterns,” said geoscientist Georgia Hole at the University of Oxford, who led the study.

“They’re taking the analysis one step further to connect changes in driftwood to changes in sea ice, and that’s where we want to go. It’s really exciting,” said Hans Linderholm, a paleoclimatologist at the University of Gothenburg in Sweden who was not involved in the research.

Important ice cubes

The Arctic Ocean collects trees that naturally fall into high-latitude rivers in North America and Eurasia. When it was cold enough, some of the trees were frozen into the sea ice. The ice then floated across the ocean, swept along by ocean currents and winds, until beaching on Svalbard’s shores. There they sat, some for hundreds of years, until researchers like Hole and Linderholm came along.

Researchers have used driftwood for climate-change studies before, but the new study is the first to test how useful Arctic driftwood is for peering into past currents and ice coverage. To check their work, the study directly compared driftwood-inferred sea ice coverage to the observational record of sea ice.

“This is a fantastic resource to say something about ocean currents and sea ice conditions,” said Linderholm. “I think they do have a case for matching [tree] provenance changes to changes in sea ice conditions, which is what we’re looking for: to have sea ice information prior to observations.”

Tracing trees

In the summer months of 2016 and 2018, Hole and her collaborators combed several beaches in northern Svalbard for driftwood. Back in the lab, they analyzed the tree rings to determine what kind of tree it was and compared the tree ring patterns of each driftwood slice to a database of measured rings from trees across the boreal forests. Hole could then trace trees to individual countries, watersheds and even rivers and see how driftwood sources varied over time.

Hole paired her driftwood data with early sea ice observations, from 1600 to 1850, thanks to records from Icelandic fishers, seal hunters and passing ships. More recent sea ice data came from airplane and satellite imagery. Finally, she compared driftwood-tracking data with sea ice conditions and currents to see how well they correlated.

Her data revealed a slow and steady northward migration of the lowest-latitude sea ice, reflecting warming, along with swings in driftwood arrivals between North America and Eurasia.

“We also saw an increase in variability in the driftwood record from 1700 to 1850, which we interpret as increased variability in sea ice,” said Hole. Colder conditions tend to have more sea ice, so earlier driftwood reflected a wider range of sources. As the Arctic warmed up and sea ice melted, less driftwood could make the long journey.

The unique method provides nuanced insights that other techniques can’t offer, and this study is just the beginning — until the Arctic loses its sea ice altogether, that is.

“It’s such a fragile system,” Hole said. “If the sea ice does decline as predicted, then this will kind of be a dying field.”

Calcium is essential for many physiological processes, including the health and function of the muscular, nervous, circulatory and digestive systems. Calcium amplifies signaling molecules that prompt a response inside cells, controls the release of neurotransmitters (chemical messengers that transmit signals from neurons), triggers the contraction of muscle cells and aids in fertilization. Calcium is also important for proper bone formation, and many processes within cells require or use calcium.

Given this wide range of functions, calcium movement and levels can serve as good indicators for biological mechanisms and changes. However, previous attempts at developing calcium sensor tools that can monitor rapid signaling changes have proven limiting due to slow responses of the sensors reported.

“The challenge is how to capture these quick changes in very specific locations,” said Yang, who is also the associate director of the Center for Diagnostics and Therapeutics and director of Advanced Translational Imaging Facility. “For example, if I have an injury in my muscle, there’s a specific muscle cell calcium change and it happens very fast.”

To better capture these signals, Yang and her colleagues have created a way to design a calcium binding site onto the surface of several fluorescent proteins. The study, published in the journal Angewandte Chemie, shows that the red calcium sensor, known as R-CatchER, is highly sensitive at detecting calcium signals in multiple cell types. The discovery is a breakthrough by Yang and her team, who have spent decades developing and refining their technique. They recently published a paper on the development of a green calcium sensor, known as G-CatchER+, in the journal iScience.

“The protein we’re using is able to identify fleeting changes and directly measure calcium activity,” said Yang. “We can monitor calcium events in healthy cells and see how they change in disease states.”

Ultimately R-CatchER could be useful for laboratory research and studies; for example, determining whether there is a connection between changes in calcium and a particular disease. Their technology could also aid in drug discovery.

“We have a unique approach to understanding how aging events or disease states are controlled by calcium. This tool could tell scientists exactly which signal pathway is related to a disease and how it changes when treated with a drug compound,” Yang said. “It could show the specific location that the drug needs to target to be effective.”

The researchers say the next step is to apply the technology in animal models to help better understand how various cell events are involved in disease.

Yang is known as a pioneer in the field she calls “calciomics,” which incorporates protein chemistry, biology, cell biology and neuroscience to develop computational studies and calcium sensor tools. In 2019, she was selected as National Academy of Inventors Fellow in honor of her work.

Co-authors of the study include chemistry doctoral student Xiaonan Deng, Donald Hamelberg, professor of chemistry, and Xinqiu Yao, postdoctoral associate in chemistry.

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The study, published in the academic journal Trends in Food Science & Technology, collects the proceedings of a symposium chaired by an Iowa State University scientist and issued a call to action on the need for new and better ways to detect and mitigate this class of chemical compounds, collectively known as per- and polyfluoroalkyl substances (PFAS). Evidence indicates exposure to high levels can lead to adverse health effects for humans and other species, and the study stresses the need for new ways to measure and study exposures to these synthetic chemicals from various sources including food.

PFAS accumulate in the environment and do not break down on their own. For instance, the compounds can contaminate waterways after leaching from products discarded in landfills, said Keith Vorst, director of the Polymer and Food Protection Consortium and an associate professor of food science and human nutrition at Iowa State. These entirely humanmade chemicals have been used in a wide range of products since the 1940s, and some states have enacted legislation to restrict their use. But their ability to persist in the environment means the compounds that already exist can continue to contaminate the environment.

“They’re out there, we need to be aware of them, and it’s really hard to eliminate them,” Vorst said. “We need to work on mitigation strategies, and we need to be monitoring them and better understand the risks they pose.”

What are PFAS? PFAS often have been used to coat food packaging as a barrier to keep grease from escaping. Vorst said paper wrappers on hamburgers are often coated in these compounds to prevent grease from leaking onto consumers’ hands. The compounds have also been used widely to coat carpets, in car interiors and in fire-fighting foams.

Some PFAS are no longer produced in the United States, but Vorst said more than 5,000 separate compounds qualify under this category, making it difficult for regulations to keep up with newly developed chemicals.

Studies have indicated that exposure to high levels of some of these chemicals can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals, according to the Environmental Protection Agency. The EPA reports the most consistent findings are increased cholesterol levels among exposed populations, and studies have found limited evidence for links between high levels of certain PFAS and low infant birth weights, effects on the immune system, cancer and thyroid hormone disruption.

Monitoring and mitigation The new paper emerged out of a virtual symposium held in June of 2020 organized by the Institute for the Advancement of Food and Nutrition Sciences. The symposium featured scientists, engineers and regulatory professionals from public, private and academic institutions. The symposium addressed science gaps for exposure routes, detection and quantification of PFAS in food. Speakers also noted that, based on limited data to date, there is little PFAS detected in food.

Polymer and Food Protection Consortium researchers Greg Curtzwiler, an assistant professor of food science and human nutrition, and Paulo Silva, adjunct assistant professor of food science and human nutrition, are working with Vorst in the laboratory to study potential mitigation strategies such as high voltage atmospheric cold plasma to change the chemistry of PFAS. This process could work by passing materials that contains PFAS, such as product packaging or even drinking water, through an engineered atmosphere to mitigate the compounds. The research team has tested the method and is working with Iowa State to patent the technology. Vorst’s PFPC lab has been testing new methodologies to detect and monitor PFAS levels in various environments as well. Much of this research was funded by the ISU Polymer and Food Protection Consortium.

“We’re looking at continuous monitoring of exposure limits,” Vorst said. “We’re trying to develop threshold limits for packaging and products. We’re also looking at how we can change these chemistries to get them out of the environment, make them less persistent or sequester them.”

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Despite widespread implementation of vaccines, bacterial meningitis is still associated with a high mortality rate and neurological consequences including hearing loss, focal neurological deficits and cognitive impairment, estimated to occur in close to half of surviving patients.

Antibiotic treatment is necessary, but with the increasing threat of antibiotic resistance, there is a growing need for new treatment strategies.

Now, in a new study performed in rats, researchers from the University of Copenhagen and Lund University were able to utilize the body’s own immune cells to kill the bacterial meningitis infection.

“In a rat model we observed that the neutrophils, a type of immune cells, form a net-like structure in the brain’s membrane, the meninges. But this particular net-structure also causes brain swelling and prevents removal of waste products. We discovered, that if we dissolved the structure — not the immune cells — the immune cells still kill the meningitis bacteria but without causing brain swelling,” says Ph.D. Chiara Pavan, first author on the study.

Immune cells block movement of brain fluid

The researchers show that immune cells entering the brain’s membrane, create a net that traps bacteria but also blocks the movement of cerebrospinal fluid. The brain is constantly cleaned by the cerebrospinal fluid that enters the tissue along blood vessels and is responsible for clearing out waste products made by the active brain cells.

This fluid transport system was named the glymphatic system by Maiken Nedergaard, and its function has been shown to be critical for avoiding accumulation of protein plaques that accumulates in patients with Alzheimer disease. Glymphatic transport of cerebrospinal fluid is also important for avoiding brain swelling in acute diseases such as stroke.

Brain swelling, also called edema, is a life threatening condition because the brain is contained within the skull. The swelling compress blood vessels resulting in loss of the brain tissue, which is fatal when the brain regions that controls breathing stops working.

That brain swelling in meningitis is caused by blockage of the glymphatic system is now shown for the first time in collaboration between Maiken Nedergaards group at the University of Copenhagen and Iben Lundgaard at Lund University.

“When the immune cells enter the brain, they eat the bacteria, but while doing so the immune cells also produce inflammatory components, including nets that cause swelling,” says Maiken Nedergaard, the lead author from the University of Copenhagen.

“The most important aspects of our study is that it suggests that meningitis can be treated by administration of an enzyme that degrades the neutrophil nets. Enzymatic removal of nets eliminated the often fatal accumulation of fluid in the brain in rats with bacterial meningitis. This novel treatment can be combined with antibiotics if needed,” she says.

Hope for an international clinical study

The researchers theorized that if the nets were dissolved, leaving just the immune cells without their nets in the meninges, it would allow the cerebrospinal fluid to pass the brain freely.

The net-like structures consist mainly of DNA, so the research team applied drugs for cutting up DNA, so-called DNase. They gave DNase to the rats infected with pneumococcus bacteria, which causes bacterial meningitis.

“We administered DNase to rats infected with the bacteria, and we were able to show that the nets dissolved. The treatment reduced brain swelling and helped in removing metabolic waste production from the infected brain. In contrast, antibiotic treatment did not have an effect on brain swelling or waste clearance,” says Maiken Nedergaard.

Based on their results, the research team now hopes to set up an international clinical study to investigate DNase in the treatment of patients with bacterial meningitis. Antibiotic resistant is increasing at an alarming rate and the drug the researchers use here is a promising alternative, and has already been approved for human use in other neurological diseases.

“We would also like to investigate how metabolic waste products removal is impaired in other disease of the brain such as multiple sclerosis or viral meningitis,” says Maiken Nedergaard.

The idea behind this approach comes from tumour research: Blocking the protein tubulin in cancer cells prevents the cells from dividing successfully — and thus also from multiplying. Physicians have long been applying this principle successfully in chemotherapy and administering tubulin-inhibiting substances to patients.

PSI researchers Natacha Gaillard and Ashwani Sharma from the Laboratory of Biomolecular Research have now extended this concept to unicellular parasites, including the pathogens that cause malaria (Plasmodium sp.) and toxoplasmosis (Toxoplasma gondii). Their cells, too, need tubulin for cell division. “If this protein no longer works the way it is supposed to, it hits the parasite hard,” says researcher Ashwani Sharma. “That makes tubulin a good point of attack for drugs. The protein has been known for a long time in tumour research, but until now it hasn’t gotten much attention in parasitology.”

The pathogens that cause malaria and toxoplasmosis are counted among the apicomplexa, a group of single-celled eukaryotic parasites. Their cells possess a true cell nucleus, and they go through both sexual and asexual phases of reproduction. Apicomplexa use humans or animals as hosts or intermediate hosts. Every year, many millions of people are afflicted by the infectious diseases they cause.

Searching for points of attack

All eukaryotes, from amoebae to humans, produce the protein tubulin. In the form of long filaments, it spans the cells as a kind of scaffolding. From this, a so-called spindle apparatus forms during cell division that pulls the chromosomes apart and distributes them to two daughter cells.

From one organism to another, the protein differs in just a few places, but these differences can potentially be important. For scientists to find active agents against the protein specific to parasites eukaryotic unicellular and thus block it, the precise structure of the protein must be known.

So PSI researchers isolated tubulin from cells of the ciliate Tetrahymena thermophila. “Its protein is virtually identical to that in apicomplexa,” explains scientist Natacha Gaillard. “And that saves us from having to work with malaria pathogens in the laboratory.”

Using the Swiss Light Source SLS and electron microscopy, the researchers deciphered the molecular structure of the protein. They then searched for a chemical compound capable of inhibiting the protein. A substance data bank yielded five candidates as potential active agents — in the laboratory, one chemical compound proved effective. The researchers named it parabulin. “It prevents tubulin from forming long, stable protein filaments. Thus it also blocks successful cell division,” Gaillard says. Parabulin blocks the protein exactly at the place analogous to where cancer drugs dock in human tubulin.

Hope for future medicine

PSI’s cooperation partners at the University of California in Irvine, USA, tested the compound on Toxoplasma gondii in human cells. And in fact, the parasite was practically incapable of reproducing any more. In contrast, parabulin had virtually no effect on human cells. “That is a good sign: The substance apparently acts only on the tubulin of the parasite — a basic requirement to be able to use it as a drug against infectious diseases,” Sharma explains.

The assumption is that parabulin works not only against Toxoplasma gondii, but also against all representatives of the apicomplexa, including the malaria pathogen. PSI has now filed a patent and plans to continue testing parabulin in the laboratory, with the aim of later developing it into a drug with the help of the pharmaceutical industry.

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Materials provided by Paul Scherrer Institute. Original written by Brigitte Osterath. Note: Content may be edited for style and length.

However, scientists caution that the benefits of managing solar parks for wild pollinators over honeybees should be prioritised where appropriate and should be assessed on a site by site basis.

A team of researchers from Lancaster University and the University of Reading has for the first time quantified the potential economic benefits and costs of installing honeybee hives on solar parks across the UK.

Solar parks are playing an increasingly important role in our national shift towards carbon zero as their contribution to electricity generation rises.

However, solar parks take up a lot of land, and as more parks are created to meet clean energy demand the it is important to look at how they can be used to bring about other environmental or commercial benefits.

One opportunity is to install honeybee hives on solar parks. A lot of solar parks are located in areas of intensive agriculture where many wild pollinator habitats have been lost or degraded. Honeybee hives provide ready-made armies providing a pollinating service to increase crop production in surrounding farmland. Although some honeybee hives have been used on solar parks, the potential economic benefits of this were, until now, unknown.

The research team used detailed land cover maps, such as those produced by the Centre of Ecology and Hydrology, to understand where solar parks are located, as well as crop distribution and rotations, existing data on honeybee hives, crop pollination requirements and crop values.

They also factored in the cost of installing and managing the honeybee hives on the solar parks.

Using crop distribution patterns in 2017, the researchers found that deploying honeybees on solar parks could have raised the value of crop yields that year by £5.9 million.

The study looked at field crops such as field beans, linseed and oilseed, top fruits such as apples and pears including varieties to make cider and perry, as well as soft fruits such as strawberries, raspberries and blackcurrants.

The findings showed that in England the crop that would potentially benefit the greatest from installing honeybee hives is oilseed, because it is so widely cultivated. Though soft fruits, and especially strawberries, would see the greatest economic benefit per land area given their high market value and relatively high dependency on honeybee pollination.

Based on 2017 data then honeybees on solar parks could boost field crop yields by £2.6 million, top fruits by £1.3 million, and soft fruit yields by £1.9 million.

There were also regional patterns in the findings with values being highest in the east and south of England because those are the areas where a greater proportion of oilseed and soft fruits are grown.

They also found that, if taken to the extreme of all UK crops being grown within a 1.5km honeybee foraging radius of solar parks around the UK, then this could boost the value of those crop yields by £80 million a year — but researchers recognise this scenario is unlikely to be possible given other factors.

Given these findings, if UK agriculture wanted to maximise the economic benefits of having honeybees on solar parks then soft fruit growing would need to be prioritised within honeybee foraging zones of 1.5km around solar parks.

However, the researchers are keen to point out that the suitability of placing honeybee hives on solar parks needs to be assessed for each location. This is because not all locations including their climate and soil types are suitable for all crops, and individual farmers have preferences about what and where they produce. Also, different crops vary in their pollination needs and so the research team’s results cannot be generalised across all crop types and varieties.

In addition, great care needs to be taken to ensure the honeybees would not be competing with already established wild pollinator species. The researchers also highlight that where possible encouraging wild pollinators would provide greater ecological benefits than installing honeybee hives.

Dr Alona Armstrong, Senior Lecturer at Lancaster University and lead author of the study, said: “Managing solar parks for honeybees can have positive impacts on crop yields and thus financial returns. But, it is important to consider the suitability on a site by site basis given the potential implications for wild pollinators and the benefits of managing sites for biodiversity more broadly.”

Professor Simon Potts from the University of Reading and co-author of the paper said: “Our study demonstrates how multi-disciplinary research can find novel land management practices which can simultaneously benefit energy producers, farmers, beekeepers and consumers.”

The researchers’ findings will help inform energy policy, future business cases for future solar parks, as well as informing sustainable investments and decisions about including honeybee hives into energy and land management.

The findings are outlined in the paper ‘Honeybee pollination benefits could inform solar park business cases, planning decisions and environmental sustainable targets’, which has been published by the journal Biological Conservation.

The paper’s authors are Alona Armstrong, Lauren Brown, Gemma Davies, and Duncan Whyatt of Lancaster University, and Simon Potts of the University of Reading.