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Researchers have developed a flying device that can land on tree branches to take samples.

This opens up a new dimension for scientists previously reserved for biodiversity researchers.

Ecologists are increasingly using traces of genetic material left behind by living organisms in the environment, called environmental DNA (eDNA), to catalogue and monitor biodiversity. Based on these DNA traces, researchers can determine which species are present in a certain area.

Obtaining samples from water or soil is easy, but other habitats—such as the forest canopy—are difficult for researchers to access. As a result, many species remain untracked in poorly explored areas.

Researchers at ETH Zurich; the Swiss Federal Institute for Forest, Snow, and Landscape Research WSL; and the company SPYGEN partnered to develop the special drone.

The drone is equipped with adhesive strips. When the aircraft lands on a branch, material from the branch sticks to these strips. Researchers can then extract DNA in the lab, analyze it, and assign it to genetic matches of the various organisms using database comparisons.

But not all branches are the same: they vary in terms of their thickness and elasticity. Branches also bend and rebound when a drone lands on them. Programming the aircraft in such a way that it can still approach a branch autonomously and remain stable on it long enough to take samples was a major challenge for the roboticists.

“Landing on branches requires complex control,” explains Stefano Mintchev, professor of environmental robotics at ETH Zurich and WSL. Initially, the drone does not know how flexible a branch is, so the researchers fitted it with a force sensing cage. This allows the drone to measure this factor at the scene and incorporate it into its flight maneuver.

Researchers have tested their new device on seven tree species. In the samples, they found DNA from 21 distinct groups of organisms, or taxa, including birds, mammals, and insects. “This is encouraging, because it shows that the collection technique works,” says Mintchev, coauthor of the study.

The researchers now want to improve their drone further to get it ready for a competition in which the aim is to detect as many different species as possible across 100 hectares of rainforest in Singapore in 24 hours.

To test the drone’s efficiency under conditions similar to those it will experience at the competition, Mintchev and his team are currently working at the Zoo Zurich’s Masoala Rainforest.

“Here we have the advantage of knowing which species are present, which will help us to better assess how thorough we are in capturing all eDNA traces with this technique or if we’re missing something,” Mintchev says.

For this event, however, the collection device must become more efficient and mobilize faster. In the tests in Switzerland, the drone collected material from seven trees in three days; in Singapore, it must be able to fly to and collect samples from 10 times as many trees in just one day.

Collecting samples in a natural rainforest, however, presents the researchers with even tougher challenges. Frequent rain washes eDNA off surfaces, while wind and clouds impede drone operation.

“We are therefore very curious to see whether our sampling method will also prove itself under extreme conditions in the tropics,” Mintchev says.

The research appears in Science Robotics.

Source: ETH Zurich

Researchers have uncovered how a unique, fast synapse keeps us from falling over.

The sensory organs that allow us to walk, dance, and turn our heads without dizziness or loss of balance contain specialized synapses that process signals faster than any other in the human body, they report.

In a discovery more than 15 years in the making, the neuroscientists, physicists, and engineers describe the mechanism of the synapses. Their work paves the way for research that could improve treatments for vertigo and balance disorders that affect as many as 1 in 3 Americans over age 40.

The new study in the Proceedings of the National Academy of Sciences describes the workings of “vestibular hair cell-calyx synapses,” which are found in organs of the innermost ear that sense head position and movements in different directions.

“Nobody fully understood how this synapse can be so fast, but we have shed light on the mystery,” says Rob Raphael, a Rice University bioengineer and coauthor of the study.

Synapses are biological junctions where neurons can relay information to one another and other parts of the body. The human body contains hundreds of trillions of synapses, and almost all of them share information via quantal transmission, a form of chemical signaling via neurotransmitters that requires at least 0.5 milliseconds to send information across a synapse.

Prior experiments had shown a faster, “nonquantal” form of transmission occurs in vestibular hair cell-calyx synapses, the points where motion-sensing vestibular hair cells meet afferent neurons that connect directly to the brain. The new research explains how these synapses operate so quickly.

In each, a signal-receiving neuron surrounds the end of its partner hair cell with a large cuplike structure called a calyx. The calyx and hair cell remain separated by a tiny gap, or cleft, measuring just a few billionths of a meter.

“The vestibular calyx is a wonder of nature,” says coauthor Anna Lysakowski of the University of Illinois Chicago. “Its large cup-shaped structure is the only one of its kind in the entire nervous system. Structure and function are intimately related, and nature obviously devoted a great deal of energy to produce this structure. We’ve been trying to figure out its special purpose for a long time.”

From the ion channels expressed in hair cells and their associated calyces, the authors created the first computational model capable of quantitatively describing the nonquantal transmission of signals across this nanoscale gap. Simulating nonquantal transmission allowed the team to investigate what happens throughout the synaptic cleft, which is more extensive in vestibular synapses than other synapses.

“The mechanism turns out to be quite subtle, with dynamic interactions giving rise to fast and slow forms of nonquantal transmission,” Raphael says. “To understand all this, we made a biophysical model of the synapse based on its detailed anatomy and physiology.”

The model simulates the voltage response of the calyx to mechanical and electrical stimuli, tracking the flow of potassium ions through low-voltage-activated ion channels from pre-synaptic hair cells to the post-synaptic calyx.

Raphael says the model accurately predicted changes in potassium in the synaptic cleft, providing key new insights about changes in electrical potential that are responsible for the fast component of nonquantal transmission; explained how nonquantal transmission alone could trigger action potentials in the post-synaptic neuron; and showed how both fast and slow transmission depend on the close and extensive cup formed by the calyx on the hair cell.

Coauthor Ruth Anne Eatock of the University of Chicago says, “The key capability was the ability to predict the potassium level and electrical potential at every location within the cleft. This allowed the team to illustrate that the size and speed of nonquantal transmission depend on the novel structure of the calyx. The study demonstrates the power of engineering approaches to elucidate fundamental biological mechanisms, one of the important but sometimes overlooked goals of bioengineering research.”

Coauthor Imran Quraishi of Yale University began constructing the model and collaborating with Eatock in the mid-2000s when he was a graduate student in Raphael’s research group and she was on the faculty of Baylor College of Medicine.

His first version of the model captured important features of the synapse, but he says gaps in “our knowledge of the specific potassium channels and other components that make up the model was too limited to claim it was entirely accurate.”

Since then, Eatock, Lysakowski, and others discovered ion channels in the calyx that transformed scientists’ understanding of how ionic currents flow across hair cell and calyx membranes.

Quraishi says, “The unfinished work had weighed on me,” and he was both relieved and excited when Chenrayan Govindaraju, a PhD student in applied physics at Rice, joined Raphael’s lab and resumed work on the model in 2018.

“By the time I started on the project, more data supported nonquantal transmission,” Govindaraju says. “But the mechanism, especially that of fast transmission, was unclear. Building the model has given us a better understanding of the interplay and purpose of different ion channels, the calyx structure, and dynamic changes in potassium and electric potential in the synaptic cleft.”

Raphael says, “One of my very first grants was to develop a model of ion transport in the inner ear. It is always satisfying to achieve a unified mathematical model of a complex physiological process. For the past 30 years—since the original observation of nonquantal transmission—scientists have wondered, ‘Why is this synapse so fast?’ and, ‘Is the transmission speed related to the unique calyx structure?’ We have provided answers to both questions.”

He says the link between the structure and function of the calyx “is an example of how evolution drives morphological specialization. A compelling argument can be made that once animals emerged from the sea and began to move on land, swing in trees and fly, there were increased demands on the vestibular system to rapidly inform the brain about the position of the head in space. And at this point the calyx appeared.”

Raphael says the model opens the door for a deeper exploration of information processing in vestibular synapses, including research into the unique interactions between quantal and nonquantal transmission.

He says the model could also be a powerful tool for researchers who study electrical transmission in other parts of the nervous system, and he hopes it will aid those who design vestibular implants, neuroprosthetic devices that can restore function to those who have lost their balance.

The research had support from the National Institutes of Health, the Hearing Health Foundation, and a seed grant from Rice University’s ENRICH program.

Source: Rice University

Coffee with milk may have an anti-inflammatory effect in humans, a new study shows.

Researchers found that a combination of proteins and antioxidants doubles the anti-inflammatory properties in immune cells. They hope to be able to study the health effects on humans.

Whenever bacteria, viruses, and other foreign substances enter the body, our immune systems react by deploying white blood cells and chemical substances to protect us.

This reaction, commonly known as inflammation, also occurs whenever we overload tendons and muscles and is characteristic of diseases like rheumatoid arthritis.

Antioxidants known as polyphenols are found in humans, plants, fruits, and vegetables. This group of antioxidants is also used by the food industry to slow the oxidation and deterioration of food quality and thereby avoid off flavors and rancidity. Polyphenols are also known to be healthy for humans, as they help reduce oxidative stress in the body that gives rise to inflammation.

But much remains unknown about polyphenols. Relatively few studies have investigated what happens when polyphenols react with other molecules, such as proteins mixed into foods that we then consume.

In a new study, researchers investigated how polyphenols behave when combined with amino acids, the building blocks of proteins. The results have been promising.

“In the study, we show that as a polyphenol reacts with an amino acid, its inhibitory effect on inflammation in immune cells is enhanced,” says Marianne Nissen Lund, a professor in the food science department at the University of Copenhagen, who headed the study in the Journal of Agricultural and Food Chemistry.

“As such, it is clearly imaginable that this cocktail could also have a beneficial effect on inflammation in humans. We will now investigate further, initially in animals. After that, we hope to receive research funding which will allow us to study the effect in humans.”

Twice the inflammation-fighting power

To investigate the anti-inflammatory effect of combining polyphenols with proteins, the researchers applied artificial inflammation to immune cells. Some of the cells received various doses of polyphenols that had reacted with an amino acid, while others only received polyphenols in the same doses. A control group received nothing.

The researchers observed that immune cells treated with the combination of polyphenols and amino acids were twice as effective at fighting inflammation as the cells to which only polyphenols were added.

“It is interesting to have now observed the anti-inflammatory effect in cell experiments. And obviously, this has only made us more interested in understanding these health effects in greater detail. So, the next step will be to study the effects in animals,” says senior author Andrew Williams of the veterinary and animal sciences department.

Anti-inflammatory coffee and milk

In previous studies, the researchers demonstrated that polyphenols bind to proteins in meat products, milk, and beer. In another new study, they tested whether the molecules also bind to each other in a coffee drink with milk. Indeed, coffee beans are filled with polyphenols, while milk is rich in proteins.

“Our result demonstrates that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that we studied. In fact, the reaction happens so quickly that it has been difficult to avoid in any of the foods that we’ve studied so far,” says Nissen Lund.

Therefore, the researcher does not find it difficult to imagine that the reaction and potentially beneficial anti-inflammatory effect also occur when other foods consisting of proteins and fruits or vegetables are combined.

“I can imagine that something similar happens in, for example, a meat dish with vegetables or a smoothie, if you make sure to add some protein like milk or yogurt,” says Nissen Lund.

Industry and the research community have both taken note of the major advantages of polyphenols. As such, they are working on how to add the right quantities of polyphenols in foods to achieve the best quality. The new research results are promising in this context as well.

“Because humans do not absorb that much polyphenol, many researchers are studying how to encapsulate polyphenols in protein structures which improve their absorption in the body,” says Nissen Lund. “This strategy has the added advantage of enhancing the anti-inflammatory effects of polyphenols.”

Additional coauthors are from the Technical University of Dresden in Germany. Independent Research Fund Denmark funded the work.

Source: University of Copenhagen