Brain circuits for locomotion evolved long before appendages and skeletons

The sea slug, Pleurobranchea californica 
Photo Credit: Fred Zwicky

Hundreds of millions of years before the evolution of animals with segmented bodies, jointed skeletons or appendages, soft-bodied invertebrates like sea slugs ruled the seas. A new study finds parallels between the brain architecture that drives locomotion in sea slugs and that of more complex segmented creatures with jointed skeletons and appendages. 

Reported in the Journal of Neuroscience, the study suggests that, rather than developing an entirely new set of neural circuits to govern the movement of segmented body parts, the insects, crustaceans and even vertebrates like mammals adapted a network of neurons, a module, that guided locomotion and posture in much simpler organisms. 

“Sea slugs may still have that module, a smallish network of neurons called the ‘A-cluster,’ with 23 neurons identified so far,” said University of Illinois Urbana-Champaign molecular and integrative physiology professor Rhanor Gillette, who led the new research. 

“The question that we addressed in this study is whether the similarities we see between sea slugs and more complex creatures evolved independently or whether those with segmented body parts and appendages may have inherited their underlying neural circuitry from a soft-bodied, bilaterally symmetrical common ancestor,” he said. 

Predators decrease prey disease levels but also population size

Microscope image showing a phantom midge larva (genus Chaoborus), top left, preying on a Daphnia dentifera water flea, bottom right. Chaoborus is a fierce predator with a complex “catching basket” on its head for quickly trapping small crustaceans like water fleas.
Photo Credit: Meghan Duffy, University of Michigan.

Nature documentaries will tell you that lions, cheetahs, wolves and other top predators target the weakest or slowest animals and that this culling benefits prey herds, whether it’s antelope in Africa or elk in Wyoming.

This idea has been widely accepted by biologists for many years and was formalized in 2003 as the healthy herds hypothesis. It proposes that predators can help prey populations by picking off the sick and injured and leaving healthy, strong animals to reproduce.

The healthy herds hypothesis has even been used to suggest that manipulating predator numbers to protect prey might be a useful conservation strategy. Even so, hard evidence supporting the hypothesis is scarce, and in recent years many of its assumptions and predictions have been questioned.

In a study published online April 26 in the journal Ecology, a University of Michigan-led research team used a pint-sized predator-prey-parasite system inside 20-gallon water tanks to test the healthy herds hypothesis.

Woodpecker helps managers promote new life in burned forests

A male Black-backed Woodpecker at Silvio O. Conte National Wildlife Refuge, Brunswick, Vermont, USA.
Photo Credit: U.S. Fish and Wildlife Service Northeast Region
(CC BY 2.0)

Scientists have created a tool based on the habitat preferences of the black-backed woodpecker to help forest managers make decisions that promote regrowth and biodiversity following wildfires.

“Wildfire is like a 10,000-piece puzzle, and climate change is rearranging the pieces,” said Andrew Stillman, a postdoctoral researcher at the Cornell Atkinson Center for Sustainability and the Cornell Lab of Ornithology and first author of “Incorporating Pyrodiversity into Wildlife Habitat Assessments for RapidPost-Fire Management: A Woodpecker Case Study,” published April 25 in Ecological Applications.

“Gigantic, severe fires are becoming the new norm in California due to drought, longer burn seasons and dense forests. But birds do really well in landscapes that are ‘pyrodiverse’ – areas where fire results in uneven patches burned at high, medium, and low severity,” Stillman said.

Black-backed woodpeckers love pyrodiversity. They prefer to build their nest cavities in newly burned areas after high severity fires. But they also like to be adjacent to areas that burned at low intensity, where their young can hide from predators among living trees that still provide cover. Because of the species’ unique habitat associations, they are sensitive to the removal of trees after fire, and forest managers use information on the woodpecker to guide their post-fire planning.

This killer protein causes pancreatic cancer

Mouse pancreas cells with high levels of the protein SRSF1; CSHL Professor Adrian Krainer found that mice with high levels of SRFS1 tend to exhibit intraepithelial neoplasia—a known precursor to the most common form of pancreatic cancer.
Image Credit: Cold Spring Harbor Laboratory

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer. It’s also one of the deadliest. More than 90% of PDAC patients die within five years of diagnosis. Usually, by the time the cancer is identified, it has already spread.

“PDAC is often found too late for treatments like chemotherapy and surgery to be very effective,” Cold Spring Harbor Laboratory (CSHL) Professor Adrian Krainer says. “But if we can clearly understand the underlying genetic mechanisms of PDAC, this might lead to earlier diagnoses and new types of therapies.”

Krainer and CSHL Postdoc Ledong Wan partnered with CSHL Professor David Tuveson to explore the role of a genetic process called RNA splicing in pancreatic cancer. RNA splicing helps DNA deliver instructions to cells for protein production. The team zeroed in on a splicing-regulator protein called SRSF1. They found that high levels of SRSF1 cause inflammation, or pancreatitis. This jumpstarts PDAC tumor development.

New black hole images reveal a glowing, fluffy ring and a high-speed jet

Scientists observing the compact radio core of M87 have discovered new details about the galaxy’s supermassive black hole. In this artist’s conception, the black hole’s massive jet is seen rising up from the center of the black hole. The observations on which this illustration is based represent the first time that the jet and the black hole shadow have been imaged together, giving scientists new insights into how black holes can launch these powerful jets. 
Illustration Credit: S. Dagnello (NRAO/AUI/NSF)

In 2017, astronomers captured the first image of a black hole by coordinating radio dishes around the world to act as a single, planet-sized telescope. The synchronized network, known collectively as the Event Horizon Telescope (EHT), focused in on M87*, the black hole at the center of the nearby Messier 87 galaxy. The telescope’s laser-focused resolution revealed a very thin glowing ring around a dark center, representing the first visual of a black hole’s shadow. 

Astronomers have now refocused their view to capture a new layer of M87*. The team, including scientists at MIT’s Haystack Observatory, has harnessed another global web of observatories — the Global millimeter VLBI Array (GMVA) — to capture a more zoomed-out view of the black hole.

The new images, taken one year after the EHT’s initial observations, reveal a thicker, fluffier ring that is 50 percent larger than the ring that was first reported. This larger ring is a reflection of the telescope array’s resolution, which was tuned to pick up more of the super-hot, glowing plasma surrounding the black hole. 

Paradoxical quantum phenomenon measured for the first time

Photo Credit: © Thomas Schweigler, TU Wien

How do quantum particles share information? A peculiar conjecture about quantum information has been experimentally confirmed at the TU Wien.

Some things are related, others are not. Suppose you randomly select a person from a crowd who is significantly taller than the average. In that case, there is a good chance that they will also weigh more than the average. Statistically, one quantity also contains some information about the other.

Quantum physics allows for even stronger links between different quantities: different particles or parts of an extensive quantum system can "share" a certain amount of information. There are curious theoretical predictions about this: surprisingly, the measure of this "mutual information" does not depend on the size of the system but only on its surface. This surprising result has been confirmed experimentally at the TU Wien and published in "Nature Physics". Theoretical input to the experiment and its interpretation came from the Max-Planck-Institut für Quantenoptik in Garching, FU Berlin, ETH Zürich and New York University.

Prolonged droughts likely spelled the end for Indus megacities

A section through the Dharamjali stalagmite that the authors studied. 
Photo Credit: Alena Giesche

The beginning of this arid period — starting at around 4,200 years ago and lasting for over two centuries — coincides with the reorganization of the metropolis-building Indus Civilization, which spanned present-day Pakistan and India.

The research identified three protracted droughts — each lasting between 25 and 90 years — during this arid period. “We find clear evidence that this interval was not a short-term crisis but a progressive transformation of the environmental conditions in which Indus people lived,” said study co-author Prof Cameron Petrie, from Cambridge’s Department of Archaeology.

The researchers charted historic rainfall by examining growth layers in a stalagmite collected from a cave near Pithoragarh, India. By measuring a range of environmental tracers — including oxygen, carbon and calcium isotopes — they obtained a reconstruction showing relative rainfall at seasonal resolution. They also used high-precision Uranium-series dating to get a handle on the age and duration of the droughts.

“Multiple lines of evidence allow us to piece together the nature of these droughts from different angles — and confirm they are in agreement,” said lead author of the research Alena Giesche, who conducted the research as part of her PhD in Cambridge’s Department of Earth Sciences.

Near-universal T cell immunity towards a broad range of bacteria

Neutralizing the bacterially derived cytotoxic bomb: the pneumococci lie in the background, an array of macrophages and dendritic cells are arranged around the central image of a T cell. Rows of TCRs interacting with the identified pneumolysin epitope bound to HLA (white) cross the length and breadth of the artwork, emphasizing their centrality in the immune response.
Illustration Credit: Dr. Erica Tandori.

Typically, T cells of the immune system respond to a specific feature (antigen) of a microbe, thereby generating protective immunity. As reported in the journal Immunity, an international team of scientists have discovered an exception to this rule. Namely, a group of divergent bacterial pathogens, including pneumococci, all share a small highly conserved protein sequence, which is both presented and recognized by human T cells in a conserved population-wide manner.

The study set out to understand immune mechanisms that protect against pneumococcus, a bacterial pathobiont that can reside harmlessly in the upper respiratory mucosae but can also cause infectious disease, especially in infants and older adults, which can range from middle ear and sinus infections to pneumococcal pneumonia and invasive bloodstream infections.

Most currently used pneumococcal polysaccharide-based conjugate vaccines (PCVs) are effective against 10–13 serotypes, but growing serotype replacement becomes a problem.

Versatile, High-Speed, and Efficient Crystal Actuation with Photothermally Resonated Natural Vibrations

Mechanically responsive molecular crystals are extremely useful in soft robotics, which requires a versatile actuation technology. Crystals driven by the photothermal effect are particularly promising for achieving high-speed actuation. However, the response (bending) observed in these crystals is usually small. Now, scientists from Japan address this issue by inducing large resonated natural vibrations in anisole crystals with UV light illumination at the natural vibration frequency of the crystal.

Every material possesses a unique natural vibration frequency such that when an external periodic force is applied to this material close to this frequency, the vibrations are greatly amplified. In the parlance of physics, this phenomenon is known as "resonance." Resonance is ubiquitous in our daily life, and, depending on the context, could be deemed desirable or undesirable. For instance, musical instruments like the guitar relies on resonance for sound amplification. On the other hand, buildings and bridges are more likely to collapse under an earthquake if the ground vibration frequency matches their natural frequency.

Interestingly, natural vibration has not received much attention in material actuation, which relies on the action of mechanically responsive crystals. Versatile actuation technologies are highly desirable in the field of soft robotics. Although crystal actuation based on processes like photoisomerization and phase transitions have been widely studied, these processes lack versatility since they require specific crystals to work. One way to improve versatility is by employing photothermal crystals, which show bending due to light-induced heating. While promising for achieving high-speed actuation, the bending angle is usually small (<0.5°), making the actuation inefficient.

Scientists discover rare element in exoplanet’s atmosphere

Illustration Credit: Bibiana Prinoth

The rare metal terbium has been found in an exoplanet’s atmosphere for the first time. The researchers at Lund University in Sweden have also developed a new method for analyzing exoplanets, making it possible to study them in more detail.

KELT-9 b is the galaxy’s hottest exoplanet, orbiting its distant star about 670 light years from Earth. The celestial body, with an average temperature of a staggering 4,000 degrees Celsius, has excited the world's astronomers since its discovery in 2016. A new study in Astronomy & Astrophysics reveals discoveries about the scalding-hot oddball's atmosphere.

“We have developed a new method that makes it possible to obtain more detailed information. Using this, we have discovered seven elements, including the rare substance terbium, which has never before been found in any exoplanet's atmosphere”, says Nicholas Borsato, PhD student in astrophysics at Lund University.

Terbium is a rare earth metal that belongs to the so-called lanthanoids. The substance was discovered in 1843 by the Swedish chemist Carl Gustaf Mosander in the Ytterby mine in the Stockholm archipelago. The substance is very rare in nature, and 99 percent of the world's terbium production today takes place in the Bayan Obo mining district in Inner Mongolia.