Study reveals location of starfish’s head

Postdoctoral scholar Laurent Formery (left) and biology Professor Christopher Lowe with starfish on the shore of Stanford’s Hopkins Marine Station, in Monterey, California.
Photo Credit: LiPo Ching / Stanford University

A new study that combines genetic and molecular techniques helps solve the riddle of starfish body plans, and how starfish start life with bilateral body symmetry – just like humans – but grow up to be adults with fivefold “pentaradial” symmetry.

If you put a hat on a starfish, where would you put it? On the center of the starfish? Or on the point of an arm and, if so, which one? The question is silly, but it gets at serious questions in the fields of zoology and developmental biology that have perplexed veteran scientists and schoolchildren in introductory biology classes alike: Where is the head on a starfish? And how does their body layout relate to ours?

Now, a new Stanford study that used genetic and molecular tools to map out the body regions of starfish – by creating a 3D atlas of their gene expression – helps answer this longstanding mystery. The “head” of a starfish, the researchers found, is not in any one place. Instead, the headlike regions are distributed with some in the center of the sea star as well as in the center of each limb of its body.

The Remains of an Ancient Planet Lie Deep Within Earth

Video Credit: California Institute of Technology

In the 1980s, geophysicists made a startling discovery: two continent-sized blobs of unusual material were found deep near the center of the Earth, one beneath the African continent and one beneath the Pacific Ocean. Each blob is twice the size of the Moon and likely composed of different proportions of elements than the mantle surrounding it.

Where did these strange blobs—formally known as large low-velocity provinces (LLVPs)—come from? A new study led by Caltech researchers suggests that they are remnants of an ancient planet that violently collided with Earth billions of years ago in the same giant impact that created our Moon.

The study, published in the journal Nature on November 1, also proposes an answer to another planetary science mystery. Researchers have long hypothesized that the Moon was created in the aftermath of a giant impact between Earth and a smaller planet dubbed Theia, but no trace of Theia has ever been found in the asteroid belt or in meteorites. This new study suggests that most of Theia was absorbed into the young Earth, forming the LLVPs, while residual debris from the impact coalesced into the Moon.

What Happens When We Pass Out? Researchers ID New Brain and Heart Connections

An image of a heart labeled by vagal sensory neurons. In a new study published in the journal Nature, UC San Diego researchers and their colleagues found that these neurons trigger fainting, laying a foundation for addressing fainting-related disorders.
Image Credit: Augustine Lab, UC San Diego

Nearly 40 percent of people experience syncope, or fainting spells, at least once in their lives. These brief losses of consciousness, whether brought by pain, fear, heat, hyperventilation or other causes, account for a significant portion of hospital emergency room visits. Yet the exact root mechanisms at play when people “pass out” largely have remained a mystery.

Publishing a new report in Nature, University of California San Diego researchers, along with colleagues at The Scripps Research Institute and other institutions, have for the first time identified the genetic pathway between the heart and brain tied to fainting.

One of their unique approaches was to think of the heart as a sensory organ rather than the longstanding viewpoint that the brain sends out signals and the heart simply follows directions. School of Biological Sciences Assistant Professor Vineet Augustine, the paper’s senior author, applies a variety of approaches to better understand these neural connections between the heart and brain.

Researchers demonstrate novel technique to observe molten salt intrusion in nuclear-grade graphite

From left, Yuxuan Zhang, James Keiser, Jisue Moon, Cristian Contescu, Erik Stringfellow (back) and Nidia Gallego, with Dino Sulejmanovic (not shown), first visualized molten salt distribution in graphite pores.
Photo Credit: Carlos Jones/ORNL, U.S. Dept. of Energy

In response to a renewed international interest in molten salt reactors, researchers from the Department of Energy’s Oak Ridge National Laboratory have developed a novel technique to visualize molten salt intrusion in graphite.

During ORNL’s revolutionary Molten Salt Reactor Experiment, or MSRE, in the 1960s, scientists first demonstrated the feasibility of nuclear fission reactions with molten fluoride salt used both as a fuel carrier and as a coolant, substituting for the solid fuel and water used in traditional nuclear reactors. Molten salt reactor designs show great promise as a means of carbon-free power generation.

To slow down neutrons so they can easily promote nuclear fission, nuclear reactors use a material called a moderator. To moderate the MSRE, scientists used synthetic graphite, which is resistant to thermal shock and dimensionally stable because of its extensive pore system resulting from the manufacturing process. MSRE graphite was custom-made and specially coated to decrease porosity and defend against detrimental effects that may occur when hydraulic and gas pressures cause molten salt to seep into graphite’s pores. Moreover, preventing molten salt intrusion avoids additional issues with waste management during reactor decommissioning.

Higher risk of cancer following 'all clear' after suspected cancer referral

Photo Credit: National Cancer Institute

Patients who were referred to urgent suspected cancer pathways, but were found not to have cancer at that time, have a higher risk of subsequent cancer in the 1-5 years following the ‘all clear’ than those who haven’t been through the referral pathways.

The study, published today in Lancet Oncology, is the first to examine the risk of cancer in patients in England who entered the urgent suspected cancer pathway but were found not to have cancer at that time. These patients were found to have a higher-than-expected risk of subsequent cancer in the 1-5 years after the initial ‘all clear’.

In England, the urgent suspected cancer referral pathway is the most common route to diagnosis. Of the 3 million patients who are referred for urgent cancer assessments in England each year, 7% are found to have cancer. This leaves a large group of patients who go through these pathways but do not have cancer at the time – a group that is currently understudied and who may be in need of support.

New study: Deep-sea pressure preserves food for microbes in the abyss

A flake of marine snow from the experiment.
Photo Credit: © Peter Stief/SDU

Scientific Frontline: "At a Glance" Summary: Deep-Sea Pressure Preserves Food for Microbes in the Abyss

• Main Discovery: Hydrostatic pressure in the deep ocean significantly reduces microbial respiration on sinking marine snow, preserving essential organic matter so it can reach the seabed to sustain deep-sea microbes.
• Methodology: Researchers utilized rotating pressure tanks to simulate the continuous sinking of 2-millimeter marine snow flakes composed of diatoms and bacteria, gradually increasing the pressure by 50 bar daily up to 1000 bar to mimic ocean depths of up to 10 kilometers.
• Key Data: Microbial respiration halted completely at 600 bar of pressure, and at 1000 bar, approximately half of the original marine snow flake remained intact.
• Significance: This mechanism clarifies how vital nutrients, including organic carbon, nitrogen, sulfur, and phosphate, survive the lengthy descent to the abyssal zone, providing crucial sustenance for the largest microbial habitat on Earth and facilitating deep-sea carbon burial.
• Future Application: Insights from this pressure-induced preservation mechanism will inform the evaluation of proposed climate change mitigation strategies, specifically those involving the artificial stimulation of marine snow to sequester atmospheric carbon dioxide in the deep ocean.
• Branch of Science: Earth Science, Marine Biology, and Microbiology.
• Additional Detail: While only an estimated 1 percent of marine snow is ultimately stored on the seabed, the steady accumulation of this organic matter over geological time scales is directly responsible for the formation of extensive fossil fuel reserves.

Risk of serious infection even in low-active IBD

Karl Mårild, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg.
 Photo Credit: Västra Götalandsregionen

Inflammatory bowel disease (IBD) is an independent risk factor for serious infection, even at very low levels of gastrointestinal inflammation. This has been shown by a study at the University of Gothenburg.

IBD is an umbrella term for chronic inflammatory bowel diseases, with a population prevalence of around 0.5%. The main types of IBD are ulcerative colitis and Crohn’s disease. Unlike irritable bowel syndrome (IBS), IBD results in visible damage to the intestinal mucous membrane.

IBD is characterized by intermittent symptoms. Periods of high disease activity are sometimes followed by longer periods of low or no activity. However, the extent to which IBD patients with low disease activity are also at increased risk of serious infections, including sepsis, has been unclear.

The current study, published in the journal Clinical Gastroenterology and Hepatology, included data on 55,626 individuals diagnosed with IBD. ‘Serious infections’ referred to infections requiring hospitalization.

Meteors Can Be Affected by Massive Objects Within and Near the Solar System

Superimposed images of FH1 flight recorded in Finland.
Photo Credit: Maria Gritsevich

Apparently interstellar meteors may be the result of accelerated meteoroid collisions with massive objects passing near or through the Solar System. This was reported by Maria Gritsevich, Associate Professor at the University of Helsinki and Senior Researcher at the Ural Federal University, at the VII Workshop on Robotic Autonomous Observatories in Malaga, Spain.

The conclusion, announced by Maria Gritsevich at the workshop as co-author of a paper and scientific article published in the journal Icarus, is due to the study of meteor FH1. This is an astronomical event registered by the Finnish Fireball Network on October 23, 2022. The speed of FH1 exceeded the speed of objects within the solar system. Thus, FH1 could be both an object in the Oort Cloud, a theoretical spherical region - the source of long-period comets - at the edge of the Solar System, and an interstellar object.

"According to our hypothesis, the trajectory of the FH1 meteoroid could have been affected by the passage of the so-called Scholz star - a double star system - close to the Sun. This event is estimated to have occurred several tens of thousands of years ago, and the gravitational perturbations caused by it changed the orbit of the meteoroid", explains Maria Gritsevich.

High metabolism is an early sign of Alzheimer’s disease

Illustration Credit: geralt

An early phase in the process of developing Alzheimer’s disease is a metabolic increase in a part of the brain called the hippocampus, report researchers from Karolinska Institutet in a study published in Molecular Psychiatry. The discovery opens up new potential methods of early intervention.

Alzheimer’s disease is the most common form of dementia and strikes about 20,000 people in Sweden every year. Researchers now show that a metabolic increase in the mitochondria, the cellular power plants, is an early indicator of the disease. 

The teams behind the study used mice that developed Alzheimer’s disease pathology in a similar way to humans. The increase in metabolism in young mice was followed by synaptic changes caused by disruption to the cellular recycling system (a process known as autophagy), a finding that was awarded the Nobel Prize in Physiology or Medicine in 2016. 

After a time, metabolism in the Alzheimer brain usually declines, which contributes to the degradation of synapses. This the researchers could also see in the older mice, which had had the disease for a longer time. 

Fossil fuels responsible for heart arrhythmias in mammals

Photo Credit: Pixabay

One of the most common byproducts of the burning of fossil fuels, phenanthrene, causes heart arrhythmias in mice, proving for the first time it is toxic to mammals, new research has discovered.

The study, led by The University of Manchester in collaboration with the University of Bristol and Moscow State University, and funded by the British Heart Foundation, is published today in the journal Environmental Health Perspectives.

Thanks to earlier work by one of the lead authors Professor Holly Shiels from Manchester in conjunction with scientists at the University of Bristol, Moscow State University, National Oceanic and Atmospheric Association (NOAA) and Stanford University, phenanthrene's toxicity to the hearts of fish and crustaceans (crayfish) has been well established.

But now the team has discovered the change also occurs in healthy mouse hearts when directly exposed to phenanthrene, mimicking what happens when we breathe in pollution.

Professor Holly Shiels said: "We've known that phenanthrene is causally linked to cardiotoxicity in fish for many years - scientists recognized this following the disastrous impact of the Exxon Valdez oil disaster in Alaska in 1989.