Using this new method, scientists should be able to analyze in mere minutes structures that would previously have taken years to decipher, says Robert Griffin, the Arthur Amos Noyes Professor of Chemistry. The new approach, which relies on short pulses of microwave power, could allow researchers to determine structures for many complex proteins that have been difficult to study until now.

“This technique should open extensive new areas of chemical, biological, materials, and medical science which are presently inaccessible,” says Griffin, the senior author of the study.

MIT postdoc Kong Ooi Tan is the lead author of the paper, which appears in Sciences Advances on Jan. 18. Former MIT postdocs Chen Yang and Guinevere Mathies, and Ralph Weber of Bruker BioSpin Corporation, are also authors of the paper.

Enhanced sensitivity

Traditional NMR uses the magnetic properties of atomic nuclei to reveal the structures of the molecules containing those nuclei. By using a strong magnetic field that interacts with the nuclear spins of hydrogen and other isotopically labelled atoms such as carbon or nitrogen, NMR measures a trait known as chemical shift for these nuclei. Those shifts are unique for each atom and thus serve as fingerprints, which can be further exploited to reveal how those atoms are connected.

The sensitivity of NMR depends on the atoms’ polarization — a measurement of the difference between the population of “up” and “down” nuclear spins in each spin ensemble. The greater the polarization, the greater sensitivity that can be achieved. Typically, researchers try to increase the polarization of their samples by applying a stronger magnetic field, up to 35 tesla.

Another approach, which Griffin and Richard Temkin of MIT’s Plasma Science and Fusion Center have been developing over the past 25 years, further enhances the polarization using a technique called dynamic nuclear polarization (DNP). This technique involves transferring polarization from the unpaired electrons of free radicals to hydrogen, carbon, nitrogen, or phosphorus nuclei in the sample being studied. This increases the polarization and makes it easier to discover the molecule’s structural features.

DNP is usually performed by continuously irradiating the sample with high-frequency microwaves, using an instrument called a gyrotron. This improves NMR sensitivity by about 100-fold. However, this method requires a great deal of power and doesn’t work well at higher magnetic fields that could offer even greater resolution improvements.

To overcome that problem, the MIT team came up with a way to deliver short pulses of microwave radiation, instead of continuous microwave exposure. By delivering these pulses at a specific frequency, they were able to enhance polarization by a factor of up to 200. This is similar to the improvement achieved with traditional DNP, but it requires only 7 percent of the power, and unlike traditional DNP, it can be implemented at higher magnetic fields.

“We can transfer the polarization in a very efficient way, through efficient use of microwave irradiation,” Tan says. “With continuous-wave irradiation, you just blast microwave power, and you have no control over phases or pulse length.”

Saving time

With this improvement in sensitivity, samples that would previously have taken nearly 110 years to analyze could be studied in a single day, the researchers say. In the Sciences Advances paper, they demonstrated the technique by using it to analyze standard test molecules such as a glycerol-water mixture, but they now plan to use it on more complex molecules.

One major area of interest is the amyloid beta protein that accumulates in the brains of Alzheimer’s patients. The researchers also plan to study a variety of membrane-bound proteins, such as ion channels and rhodopsins, which are light-sensitive proteins found in bacterial membranes as well as the human retina. Because the sensitivity is so great, this method can yield useful data from a much smaller sample size, which could make it easier to study proteins that are difficult to obtain in large quantities.

The research was funded by the National Institutes of Biomedical Imaging and Bioengineering, the Swiss National Science Foundation, and the German Research Foundation.

The group of scientists — led by Selman Sakar at EPFL and Bradley Nelson at ETH Zurich — drew inspiration from bacteria to design smart, biocompatible microrobots that are highly flexible. Because these devices are able to swim through fluids and modify their shape when needed, they can pass through narrow blood vessels and intricate systems without compromising on speed or maneuverability. They are made of hydrogel nanocomposites that contain magnetic nanoparticles allowing them to be controlled via an electromagnetic field.

In an article appearing in Science Advances, the scientists describe the method they have developed for “programming” the robot’s shape so that it can easily travel through fluids that are dense, viscous or moving at rapid speeds.

Embodied intelligence

When we think of robots, we generally think of bulky machines equipped with complex systems of electronics, sensors, batteries and actuators. But on a microscopic scale, robots are entirely different.

Fabricating miniaturized robots presents a host of challenges, which the scientists addressed using an origami-based folding method. Their novel locomotion strategy employs embodied intelligence, which is an alternative to the classical computation paradigm that is performed by embedded electronic systems. “Our robots have a special composition and structure that allow them to adapt to the characteristics of the fluid they are moving through. For instance, if they encounter a change in viscosity or osmotic concentration, they modify their shape to maintain their speed and maneuverability without losing control of the direction of motion,” says Sakar.

These deformations can be “programmed” in advance so as to maximize performance without the use of cumbersome sensors or actuators. The robots can be either controlled using an electromagnetic field or left to navigate on their own through cavities by utilizing fluid flow. Either way, they will automatically morph into the most efficient shape.

Inspired by nature

“Nature has evolved a multitude of microorganisms that change shape as their environmental conditions change. This basic principle inspired our microrobot design. The key challenge for us was to develop the physics that describe the types of changes we were interested in, and then to integrate this with new fabrication technologies,” says Nelson. In addition to offering enhanced effectiveness, these miniaturized soft robots can also be manufactured easily at a reasonable cost. For now, the research team is working on improving the performance for swimming through complex fluids like those found in the human body.

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The double-slit experiment is of fundamental importance in physics. More than 200 years ago, Thomas Young diffracted light at two adjacent slits, thus generating interference patterns (images based on superposition) behind this double slit. That way, he demonstrated the wave character of light. In the 20th century, scientists have shown that electrons or molecules scattered on a double slit show the same interference pattern, which contradicts the classical expectation of particle behaviour, but can be explained in quantum-mechanical wave-particle dualism. In contrast, the researchers in Cologne investigated an iridium oxide crystal (Ba3CeIr2O9) by means of resonant inelastic X-ray scattering (RIXS).

The crystal is irradiated with strongly collimated, high-energy X-ray photons. The X-rays are scattered by the iridium atoms in the crystal, which take over the role of the slits in Young’s classical experiment. Due to the rapid technical development of RIXS and a skilful choice of crystal structure, the physicists were now able to observe the scattering on two adjacent iridium atoms, a so-called dimer.

‘The interference pattern tells us a lot about the scattering object, the dimer double slit’, says Professor Markus Grueninger, who heads the research group at the University of Cologne. In contrast to the classical double-slit experiment, the inelastically scattered X-ray photons provide information about the excited states of the dimer, in particular their symmetry, and thus about the dynamic physical properties of the solid.

These RIXS experiments require a modern synchrotron as an extremely brilliant X-ray light source and a sophisticated experimental setup. To specifically excite only the iridium atoms, scientists have to select the very small proportion of photons with the right energy from the broad spectrum of the synchrotron, and the scattered photons are selected even more strictly according to energy and direction of scattering. Only a few photons remain. With the required accuracy, these RIXS experiments are currently only possible at two synchrotrons worldwide, including the ESRF (European Synchrotron Radiation Facility) in Grenoble, where the team from Cologne conducted their experiment.

‘With our RIXS experiment, we were able to prove a fundamental theoretical prediction from 1994. This opens a new door for a whole series of further experiments that will allow us to gain a deeper understanding of the properties and functionalities of solids’, says Grueninger.

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The new study, with its first author being Anna Barbanti (UB-IRBio), represents the first genetic study of the reintroduction project of this endangered species, and the wild population of green turtles in the Cayman Islands, a British Overseas Territory.

According to the conclusions, the current wild population of green turtle in the Cayman Islands has been recovered as a result of the reintroduction process; it presents a high genetic diversity and shows no difficulties regarding breeding. However, the authors of the study recommend conducting a genetic monitoring of the species in this Atlantic Ocean region since it shows a differential genetic heritage compared to other populations of the Caribbean. Other participants in this study were Clara Martín and Víctor Ordóñez (UB-IRBio), and other experts from the University of Exeter, the Cayman Turtle Farm (CTF) and the Department of Environment of the Cayman Islands Government (United Kingdom).

At the limits of survival due human overexploitation

The green turtle (Chelonia mydas) is a migratory species globally distributed in tropical and subtropical latitudes -nesting beaches in the Mediterranean basin- which has been quite exploited by human activity. This species is the biggest one within the family of Cheloniidae -adults can weigh over 200 kg- and one of the species of marine turtles with a more natal phylopatric behaviour (it comes back to their birth place to lay its eggs). Factors such as marine pollution, loss of natural habitat, fishing pressure and bycatches endanger the survival of these turtles, classified as an endangered species according to the International Union for Conservation of Nature (IUCN).

During the eighties, overexploitation of the green turtle in the Cayman Islands caused the disappearance of nesting populations. To recover this endangered population, a program of reintroduction of the species was launched, with individuals of the Cayman Turtle Farm (CTF). Forty years later, data show that the nesting population of the Cayman Islands has been restored but researchers did not know if this was the result of the reintroduction process or the natural recovery of the population for the improvement of threatening factors.

In the new study, experts analyse several genetic markers to see the degree of parentage of the natural population of the green turtle in the Cayman Islands with the breeding individuals in the farm, and therefore evaluate the effect of the reintroduction process on wild population.

“In wildlife, genetic diversity is a key factor that eases the adaptation of populations in the natural environment and their tolerance to environmental changes. In this context, it is crucial to conduct a genetic monitoring of the reintroduction processes to evaluate their success and the potential consequences for the target species of the reintroduction,” says Carlos Carreras, member of the Department of Genetics, Microbiology and Statistics of the UB and IRBio. “A threatened population -he continues- reduces their survival options due excessive inbreeding but a poorly planned reintroduction can have negative consequences because of the mix of genetically different beings, since they could create hybrids that are not feasible to the environmental conditions of the population.”

The population of the wild green turtle has a tight genetic relationship with the ones in CTF, the new study reveals. According to Marta Pascal, member of the mentioned Department and IRBio, “90 % of the wild individuals were related to the captive stock. This means the reintroduction process was very important in the recovery of threatened populations.”

The reintroduction process started in the farm with individuals of distant populations, and this explains why the genetic diversity of first generation turtles is higher than their parents’. This genetic diversity of the initial population has been changing as a consequence of the captivity process -as expected- but also because of the effects of the CTF population management. For instance, they use beings from the same cohort as reproductive adults to replace the losses hurricane Michelle caused in 2001, a strategy that has increased the degree of parentage among reproductive individuals in the farm. Therefore, scientific studies like the one in Molecular Ecology, are essential tools to take the right decisions in the management of threatened species.

Lights and shades in the reintroduction of endangered species

Current labelling studies show that there is a population between one hundred and one hundred and fifty reproductive female adults in the Cayman Islands. In this situation of biodiversity protection, the reintroduction programs for endangered species can become an effective tool of preservation but can also be inefficient, and can even have negative consequences for the threatened populations and natural ecosystems. “Therefore, it is essential to design these programs of reintroduction of threatened species with scientific rigor and to conduct a long term scientific monitoring to assess its success and the potential consequences for the species,” warn the experts.

The genetic studies carried out by the Evolutionary Genetics team of the UB and IRBio are part of the first scientific initiative to assess the global impact of the reintroduction of the species Chelonia mydas in the Cayman Islands from different sides: social and economic, commercial, and even gastronomic. This research study has been funded by the European Regional Development Fund (FEDER), as well as the Darwin project, with the support of Bosch i Gimpera Foundation (FBG) of the UB and the Department for Environment, Food and Rural Affairs (United Kingdom).

Earstones help the fish know up from down, determine their speed through the water and aid hearing. The researchers from UK, Norway and Denmark have now shown that it also acts as a fitness watch, revealing whether the fish had an active life or was completely relaxed.

Earstones — the fish fitness watch

The carbon in the earstone originates from two sources: the water the fish lives in and the food it eats to meet its energy demands. The carbon from both sources mix in the blood before some of it ends up in the earstone as calcium carbonate. By carefully analyzing the calcium carbonate, the researchers can determine the how much of the carbon originates from the water or the diet as the two sources have different proportions of the light and the heavy carbon isotopes. When the fish’s metabolism increases, for example when it encounters warmer water or is more active, it burns off more food and the proportion of carbon from the food in its earstone increases.

A treasure chest of data

Earstones grow new layers similar to the rings in a tree trunk. Every little increment in the otolith growth reflects the growth of the fish and can be used to document its age. This data can be recovered even after the fish has died. Now, by measuring carbon isotopes in the individual layers, the researchers can tell how the metabolism of a fish has changed on a monthly basis during its life, including how seasonal variations in temperature, food and the fish’s behaviour have affected its metabolism.

“Our new results is the key to a treasure chest of new discoveries,” says Dr Clive Trueman, from the University of Southampton, who is one of the co-authors behind the paper that is being published in the journal Communications Biology today.

Dr Ming-Tsung Ching, another co-author from Aarhus University in Denmark added “Now we have the tools to measure and understand how fish are being affected by and adapting to changes in the environment, and how much the fish must eat to gain enough energy to swim, grow and reproduce. This new tool will help us improve our predictions of what happens to the fish including commercially important fish like cod when the environment changes.”

Long time series

Otoliths have been studied and stored for over 100 years, so now we can go back in time and see how the metabolism of fish has changed in response to industrial fishing and long-term climate change. But it is not only these scientific collections that contain exciting material for research. It is possible to find very old otoliths in archaeological sites known as middens. These otoliths, millennia old, still contain the carbon signal that reveals the metabolic rate of the fish.

“We can use knowledge about ancient fish metabolism to learn about the ability of the fish to adapt to environmental conditions that may come to exist in the near future, or how fish respond to changes in water temperature or food availability. What happens to the fish when the waters become warmer than they are now?,” says Prof. Grønkjaer from Aarhus University in Denmark.

Dr Trueman added: “We have already started looking into the metabolic rates of cod living in the cold, but warming waters, around Greenland. We have otoliths from fish in that region dating back to 1926 which will help us understand the impact of climate on the well-being of these fish.

“Otoliths are like the black box of fish, they contain an enormous library of information written in a language that we are now starting to decipher.”

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The researchers studied wave patterns created within Saturn’s rings by the planet’s internal vibrations. In effect, the rings act as an extremely sensitive seismograph by responding to vibrations within the planet itself.

Similar to Earth’s vibrations from an earthquake, Saturn responds to perturbations by vibrating at frequencies determined by its internal structure. Heat-driven convection in the interior is the most likely source of the vibrations. These internal oscillations cause the density at any particular place within the planet to fluctuate, which makes the gravitational field outside the planet oscillate at the same frequencies.

“Particles in the rings feel this oscillation in the gravitational field. At places where this oscillation resonates with ring orbits, energy builds up and gets carried away as a wave,” explained Christopher Mankovich, a graduate student in astronomy and astrophysics at UC Santa Cruz.

Mankovich is lead author of a paper, published January 17 in the Astrophysical Journal, comparing the wave patterns in the rings with models of Saturn’s interior structure.

Most of the waves observed in Saturn’s rings are due to the gravitational effects of the moons orbiting outside the rings, said coauthor Jonathan Fortney, professor of astronomy and astrophysics at UC Santa Cruz. “But some of the features in the rings are due to the oscillations of the planet itself, and we can use those to understand the planet’s internal oscillations and internal structure,” he said.

Mankovich developed a set of models of the internal structure of Saturn, used them to predict the frequency spectrum of Saturn’s internal vibrations, and compared those predictions with the waves observed by Cassini in Saturn’s C ring. One of the main results of his analysis is the new calculation of Saturn’s rotation rate, which has been surprisingly difficult to measure.

As a gas giant planet, Saturn has no solid surface with landmarks that could be tracked as it rotates. Saturn is also unusual in having its magnetic axis nearly perfectly aligned with its rotational axis. Jupiter’s magnetic axis, like Earth’s, is not aligned with its rotational axis, which means the magnetic pole swings around as the planet rotates, enabling astronomers to measure a periodic signal in radio waves and calculate the rotation rate.

The rotation rate of 10:33:38 determined by Mankovich’s analysis is several minutes faster than previous estimates based on radiometry from the Voyager and Cassini spacecraft.

“We now have the length of Saturn’s day, when we thought we wouldn’t be able to find it,” said Cassini Project Scientist Linda Spilker. “They used the rings to peer into Saturn’s interior, and out popped this long-sought, fundamental quality of the planet. And it’s a really solid result. The rings held the answer.”

The idea that Saturn’s rings could be used to study the seismology of the planet was first suggested in 1982, long before the necessary observations were possible. Coauthor Mark Marley, now at NASA’s Ames Research Center in Silicon Valley, subsequently fleshed out the idea for his Ph.D. thesis in 1990, showed how the calculations could be done, and predicted where features in Saturn’s rings would be. He also noted that the Cassini mission, then in the planning stages, would be able to make the observations needed to test the idea.

“Two decades later, people looked at the Cassini data and found ring features at the locations of Mark’s predictions,” Fortney said.

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Each of the 20 billion neurons in the cerebral cortex receives thousands of synaptic connections from other neurons, forming complex neural networks that make sensation, perception, movement, and higher cognitive functions possible. Ultimately the function of these networks depends on events that occur within a neuron’s dendrite — extensions from the neuron’s cell body that resemble branches of a tree and receive synaptic connections from the axons of other neurons, A critical piece of the puzzle of cortical networks that continues to challenge neuroscientists is understanding the functional organization of synapses within a neuron’s dendritic field. This requires determining the functional properties of the synaptic inputs a neuron receives (what they are communicating), the source of the inputs (where they are coming from), and how they are arranged within the dendrite. In a new article in Neuron, MPFI researchers detail how they recently devised new methods to answer these questions, revealing a functional order to the arrangement of distant and local synaptic inputs within a neuron’s dendritic field that may play an important role in coordinating network activity.

Graduate student Kuo-Sheng Lee, along with other members of the Fitzpatrick lab, explored this question in the mouse visual cortex by mapping the synaptic inputs that link the two cortical hemispheres via a fiber bundle called the corpus callosum. This pathway is thought to play a critical role in coordinating the activity of the two cerebral hemispheres, and, for the visual system, unifying our binocular view of the world. They developed an approach that would permit them to visualize the individual dendritic spines of a neuron (small dendritic specializations that receive excitatory synaptic inputs), characterize their functional properties, and determine whether they receive callosal inputs.

To visualize the activity of individual dendritic spines, Lee et al., used an advanced imaging technique that relies on calcium signals that are detected as changes in fluorescence. By watching the dendritic spines ‘light up’ with activity in the living brain, they could present different visual stimuli to the animal and determine which was most effective. The dendritic spines, like most of the cells in visual cortex, respond selectively to the orientation of edges in the visual scene, so this was the functional property they chose to define for each spine. Then to determine whether a spine received synaptic input from the callosum, Lee et al. used direct stimulation of the other hemisphere and looked to see which of the dendritic spines would light up. Having found that a small percentage of spines were reliably and consistently activated by stimulating callosal inputs, then they were ready to address how are they were arranged within the dendritic field.

One interesting possibility was that the callosal inputs with similar orientation preference might be clustered together within the dendritic field. Previous results had provided evidence for clustering of synaptic inputs by functional properties and suggested that coactivation of clustered inputs could amplify their impact on the neuron’s response. But, when they performed the analysis, they found that close pairs of spines receiving callosal input were no more likely to have similar orientation preference than a random distribution of the spines within the dendritic field. Then they considered another possibility. Perhaps the callosal spines were clustered with non-callosal spines with the same orientation preference, bringing spines with distant and local inputs that have similar orientation preference into close proximity on the dendrite. When they took pairs of close spines, one a callosal recipient and the other non-callosal recipient, and examined the orientation preference of the pairs, they were excited to find that they were they more similar to each other than would be expected by chance.

Lee et al. recognized that their conclusions would be strengthened if they could confirm the functional evidence for orderly local and callosal connectivity with another experimental approach: defining the synaptic connections anatomically. To accomplish this, they used a novel technique called expansion microscopy to anatomically visualize the nanoscale synaptic contacts with conventional light microscopy. The results were consistent with the functional stimulation results, demonstrating that callosal inputs and local inputs (derived from the region right around the targeted neuron) that exhibit similar or¬ientation preference are clustered within the dendritic field.

These observations put the concept of functional clustering into a whole new context: ‘birds of a feather flock together’ and ‘opposites attract’. Functional clustering represents a fine scale spatial pattern of specificity in connections within the dendritic field that can bring together inputs that have similar properties and are derived from different networks. Combined with the evidence that functional clustering of spines in the dendritic field can amplify their impact on neuronal response, neurons in the visual cortex could use this strategy to generate robust responses to orientation-matched inputs from the two hemispheres, contributing to a seamless perception of the visual world. A similar structure may apply to callosal connections that link other areas of the cortex, a fine-scale organization of synapses within the dendrites of individual neurons that has ramifications for large-scale network function.

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With nearly 35% of mangroves lost from around the world since the 1980s, primarily due to coastal development, the future loss of seemingly small mangrove patches to new construction projects such as airports or aquaculture is extremely worrying for coastal communities and Critically Endangered wildlife like the pygmy three-toed sloth (Bradypus pygmaeus) and green sawfish (Pristis zijsron) that are protected by, and reliant on, these habitats.

Large swathes of mangroves in Southeast Asia, such as in the Philippines, have been cleared to make way for aquaculture, mainly shrimp and fish ponds. Elsewhere, in the Maldives, mangroves are being cleared to make way for a controversial new airport to be built. Here, despite assurances being made that only 30% of mangroves would be directly affected as a result, almost 70% may have already been destroyed.

Mangroves offer vital ecosystem services to local communities, providing food, coastal protection from extreme weather events, fisheries support and key natural carbon storage facilities. They clean water by trapping sediments and pollutants and help mitigate the impacts of storm surges and tsunamis on coastal communities, particularly in vulnerable low-lying island nations.

Despite warnings from leading scientists about the dire ramifications of losing mangroves, the conversion and degradation of mangrove forests for infrastructure or agriculture still occur — especially for smaller mangrove patches.

The letter states that the continued loss of small patches of mangroves could result in the disconnect of habitats, meaning natural wildlife corridors used by species to move freely throughout the landscape could be lost. This could generate new barriers for wildlife being able to adapt to the effects of climate change, as well as low-lying island communities becoming increasingly vulnerable to extreme weather patterns such as typhoons during monsoon seasons.

Dr David Curnick, Post-doctoral Researcher at ZSL’s Institute of Zoology and member of the IUCN SSC Mangrove Specialist Group said: “Given the recent Intergovernmental Panel on Climate Change’s projections, we simply cannot afford to lose more mangrove forests, irrespective of their size.

“All too often mangroves are regarded as irrelevant swamps or wastelands — yet they’re incredibly important ecosystems. Globally, yes, mangrove conservation is being looked at, but it’s these smaller patches of mangroves in remote areas that need greater recognition.

“We need governments to move away from policy decisions that prioritise large areas and short-term local political gains, and instead adopt a more well-rounded long-term vision, ensuring the value of smaller mangrove patches are appreciated and safeguarded.”

Though Mangroves are covered under international agreements including the Convention on Biological Diversity (CBD), the United Nations Framework Convention on Climate Change (UNFCCC) and Convention for the Protection of World Cultural and Natural Heritage — these are only recommendations and thus mangrove forests are still one of the most severely threatened and undervalued ecosystems on Earth.

The ecosystem services provided by mangroves are conservatively estimated at around £1.2 billion (US $1.6 billion) globally, suggesting that no matter their size, they are key to meeting commitments like the Paris Climate Agreement.

ZSL hosts the IUCN SSC Mangrove Specialist Group and supports projects around the globe helping to rehabilitate mangrove forests using ‘Community-based Mangrove Rehabilitation approaches in countries like the Philippines, where over 50% of mangroves have been lost. Over a four-year period, close to 100,000 mangroves have been planted, with the rehabilitation of 107.8 hectares of mangrove forest well underway.