New Technique Visualizes Every Pigment Cell of Zebrafish in 3D

3D image of melanin in a zebrafish sample captured by micro-computed tomography.
Credit: Spencer R. Katz and Daniel J. Vanselow/Penn State College of Medicine

Researchers have developed a new technique that images every pigment cell of a whole zebrafish in 3D. The work, recently reported in the journal eLife, could help scientists understand the role of melanin in skin cancer.

Melanin is a natural pigment that gives color to the skin, hair, and eyes in humans and animals. Melanin also has implications in melanin-containing cancers, or melanomas, which are typically staged by the depth of penetration in skin.

But studying melanin directly with a conventional microscope is challenging because the pigment blocks light. So Keith C. Cheng, a distinguished professor of pathology, pharmacology and biochemistry, and molecular biology at Penn State College of Medicine, turned to X-ray imaging, which can pass through optically opaque matter like melanin.

To perform the imaging, Cheng partnered with Dula Parkinson, a staff scientist at Berkeley Lab’s Advanced Light Source (ALS), to image two sets of zebrafish samples – one with the normal pigmentation associated with the zebrafish’s characteristic black stripes, and another from a mutant zebrafish line with lighter stripes called golden. Over 15 years ago, Cheng and his lab discovered a key gene implicated in human skin color by studying golden zebrafish. That discovery highlighted the zebrafish’s utility as an animal model of human pigmentation in skin disorders such as albinism or melanoma skin cancer.

Omicron may be significantly better at evading vaccine-induced immunity, but less likely to cause severe disease

As the SARS-CoV-2 virus replicates and spreads, errors in its genetic code can lead to changes in the virus. On 26 Novembe
r 2021, the World Health Organization designated the variant B.1.1.529, first identified in South Africa, a variant of concern, named Omicron. The variant carries a large number of mutations, leading to concern that it will leave vaccines less effective at protecting against infection and illness.

Working in secure conditions, a team led by Professor Ravi Gupta at the Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, created synthetic viruses – known as ‘pseudoviruses’ – that carried key mutations found in the Delta and Omicron strains. They used these to study the virus’s behavior.

The team, which included collaborators from Japan, including Dr Kei Sato of Tokyo University, has released its data ahead of peer review because of the urgent need to share information relating to the pandemic, and particularly the new Omicron variant.

Professor Gupta and colleagues tested the pseudoviruses against blood samples donated to the NIHR COVID-19 BioResource. The blood samples were from vaccinated individuals who had received two doses of either the AstraZeneca (ChAdOx-1) or Pfizer (BNT162b2) vaccines.

On average, Omicron required around a ten-fold increase in the concentration of serum antibody in order to neutralize the virus, compared to Delta. Of particular concern, antibodies from the majority of individuals who had received two doses of the AstraZeneca vaccine were unable to neutralize the virus. The data were confirmed in live virus experiments.

Researchers create artificial cell cortex, a system to study how cells divide

Animal cells are bound by a structure called a cell cortex—and this structure, researchers say, is a bit like a tent.

A tent is constructed of a shell with a zippered opening that controls what can go into and out of the tent. This shell is held up by a system of poles. Similarly, an animal cell cortex is composed of a cell membrane that controls what enters the cell.

The cortex also contains proteins, which help the cell keep its shape. One of these key proteins, called actin, is a polymer with a linear structure—like a tent pole. But unlike a tent, a cell’s cortical proteins aren’t stationary. They move along the cell membrane, freely assembling and moving apart over time, in a process called “cortical excitability.”

When these proteins begin to form wave patterns, it’s a sign that the cell is preparing to divide. But studying this process within the cell membrane is difficult. Now, University of Michigan researchers have developed an approach to study these wave patterns outside of a cell by developing a cell-free artificial cortex.

As a cell prepares to divide, its cell cortex proteins begin to move. First, its cortical proteins form an excitable wave, like spectators performing “the wave” at a football stadium. Second, cortical proteins organize into coherent oscillations, which behave like blinking holiday lights, associating and dissociating with the membrane at regular intervals.
Image credit: Jennifer Landino, A. Miller lab

Vaccine study flips traditional view of product scarcity driving demand

 The first doses of the Pfizer COVID-19 vaccine are administered
to Iowa State University health care employees on
Friday, December 18, 2020, at the Thielen Student Health Center.
Credit: Christopher Gannon/Iowa State University

Anyone who has taken an economics class probably remembers learning about scarcity. The concept of demand outpacing supply applies to the toilet paper shortage at the onset of the COVID-19 pandemic and helps explain how a spike in home-improvement projects last year contributed to skyrocketing lumber prices.

“Previous research on product scarcity shows people will desire something more when it isn’t as easily accessible. Since scarcity signals value, people are willing to make more of an effort or pay more to acquire it,” said Beatriz Pereira, assistant professor of marketing at Iowa State University.

Last year, as COVID-19 cases surged across the U.S., Pereira and a team of researchers knew the initial supply of vaccines would be limited. It seemed like the perfect opportunity to test whether vaccine scarcity drives demand. But the researchers’ newly published findings in Psychology & Marketing reveal the opposite: Participants were less interested in rolling up their sleeves when they thought vaccines were scarce. The researchers point to compassion for the vulnerable as a driving factor.

At the time of the first survey, COVID-19 vaccines were not yet available to the general public.

Over 300 college students were asked to imagine a scenario where manufacturers were working nonstop to produce enough vaccines for everyone, but due to limited supply, priority was being given to people considered high risk. Half of the participants were told that vaccine doses were limited in their area, while the other half were told there were plenty of doses available. The survey then asked both groups of participants the likelihood that they would book a vaccination appointment if their doctor said they could get a shot the following week.

“Interest in booking an appointment dropped by as much as 15% when the participants perceived vaccines as scarce,” said Pereira.

Gum disease increases risk of other illness such as mental health and heart conditions

A University of Birmingham-led study shows an increased risk of patients developing illnesses including mental ill-health and heart conditions if they have a GP-inputted medical history of periodontal (gum) disease.

Experts carried out a first of its kind study of the GP records of 64,379 patients who had a GP-inputted recorded history of periodontal disease, including gingivitis and periodontitis (the condition that occurs if gum disease is left untreated and can lead to tooth loss). Of these, 60,995 had gingivitis and 3,384 had periodontitis. These patients’ records were compared to those of 251,161 patients who had no record of periodontal disease. Across the cohorts, the average age was 44 years and 43% were male, while 30% were smokers. Body Mass Index (BMI), ethnicity and deprivation levels were also similar across the groups.

The researchers examined the data to establish how many of the patients with and without periodontal disease go on to develop cardiovascular disease (e.g., heart failure, stroke, vascular dementia), cardiometabolic disorders (e.g., high blood pressure, Type 2 diabetes), autoimmune conditions (e.g., arthritis, Type 1 diabetes, psoriasis), and mental ill-health (e.g., depression, anxiety and serious mental illness) over an average follow-up of around three years.

From the research, published today in journal BMJ Open, the team discovered that those patients with a recorded history of periodontal disease at the start of the study were more likely to go on and be diagnosed with one of these additional conditions over an average of three years, compared to those in the cohort without periodontal disease at the beginning of the research. The results of the study showed, in patients with a recorded history of periodontal disease at the start of the study, the increased risk of developing mental ill-health was 37%, while the risk of developing autoimmune disease was increased by 33%, and the risk of developing cardiovascular disease was raised by 18%, while the risk of having a cardiometabolic disorder was increased by 7% (with the increased risk much higher for Type 2 diabetes at 26%).

Carbon Dioxide Cold Traps Offer Potential Lunar Resource

South polar region of the Moon. Areas that act as CO2 cold traps are colored. Black contours show the boundaries of H2O cold traps. The background map is shaded relief. 
Credit: Norbert Schorghofer.

The existence of carbon dioxide (CO2) cold traps on the Moon has been confirmed, offering a potential resource for future exploration of the lunar surface, according to a new paper by Planetary Science Institute Senior Scientist Norbert Schorghofer.

“After water, carbon is probably the most important resource on the Moon. It can be used for the production of rocket fuel, but also for biomaterials and steel. If we have to bring carbon or fuel from earth, it drives up the cost of sustained presence. It's part of ‘living off the land,’ or in-situ resource utilization,” said Schorghofer, lead author of “Carbon Dioxide Cold Traps on the Moon” that appears in Geophysical Research Letters. PSI’s Matthew A. Siegler is a co-author on the paper.

Various volatiles can be cold-trapped in permanently shadowed craters near the lunar poles. The existence of carbon dioxide cold traps has previously been surmised, but the required temperatures are near the lowest surface temperatures that have been reliably measured.

Retinal immune cells may hold key to preventing diabetes-related vision loss

New research could form the basis for developing life-changing therapies that limit the impact of diabetic eye disease – a condition that could potentially affect some 1.7 million Australians, suffering from type 1 and type 2 diabetes.

Published in PNAS, the University of Melbourne research uncovers how retinal immune cells change during diabetes, which may lead to new treatments that can be used from an early stage of disease, well before any loss of vision.

“Until recently, immune cells of the nervous system were thought to sit quietly, only responding when injury or disease occurred. Our finding expands our knowledge of what these cells do and shows a highly unusual mechanism by which blood vessels are regulated. This is the first time, immune cells have been implicated in controlling blood vessel and blood flow,” co-author Professor Erica Fletcher said.

Almost everyone with type 1 diabetes, and more than 60 per cent of those with type 2 diabetes, will develop some form of diabetic eye disease within 20 years of diagnosis, according to Diabetes Australia. With an additional 280 people developing the disease every day, the breakthrough has important implications.

The research team found a specific type of immune cell, called microglia, contact both blood vessels and neurons in the retina and are able to change blood flow to meet the needs of neurons.

Deforestation-fueled heat already affecting millions of outdoor workers in the tropics

Population in deforested areas with heat exposure corresponding to greater than two hours of safe work time lost at present (top) and with additional global warming. Some of the most-affected areas are in Southeast Asia, Central America and South America.Parsons et al./One Earth

Pledges made in Glasgow at the recent United Nations Climate Change Conference, or COP26, are urgently needed by communities on the front lines of forest loss, according to a new study by a multidisciplinary team from the University of Washington, Duke University and The Nature Conservancy. New research shows how much local temperature rises in the tropics — compounded by accelerating deforestation — may already be jeopardizing the well-being and productivity of outdoor workers.

The study, published Dec. 17 in One Earth, compares established recommendations on safe working conditions with satellite observations of temperature and forest cover and population data. Results show how warming associated with recent deforestation, from 2003 to 2018, has increased heat exposure for 4.9 million people globally, including 2.8 million outdoor workers.

“Our findings highlight the vital role tropical forests play in effectively providing natural air-conditioning services for populations vulnerable to climate change — given these are typically regions where outdoor work tends to be the only option for many, and where workers don’t have the luxury of retiring to air-conditioned offices whenever the temperature rises to intolerable levels,” said lead author Luke Parsons, who began the study as a postdoctoral researcher at the University of Washington and is now a postdoctoral researcher at Duke University.

Coronal rain on a cold star

Coronal rain on the sun with Earth superimposed for scale. New high-resolution spectrographic observations of a flare on a faint distant star using the Penn State Habitable-zone Planet Finder could contain the first evidence of a similar phenomenon on an ultracool, small M-dwarf star.
Credit: NASA/SDO

High-resolution spectroscopic observations of a stellar flare on a small, cool star indicate the possibility of coronal rain, a phenomenon that has been observed on our sun but not yet confirmed on a star of this size. This faint star, known as vB 10, which is about a tenth the size of the sun and produces less than 1% of the sun’s energy, was studied using the Penn State Habitable-zone Planet Finder (HPF) at the large Hobby Eberly Telescope (with its 10 m mirror). These observations with the HPF spectrograph allowed researchers to measure a shift in the wavelength of certain atomic lines from the flare that are consistent with hot plasma raining back down on the star’s surface and are similar to observations of coronal rain from the sun.

A paper describing the observations, by a team led by Penn State scientists, includes a time-series analysis of the flare and could help astronomers put constraints on the energy and frequency of such events. The paper has been accepted for publication in The Astrophysical Journal and is available online.

Fire and Ice

How could ice loss in the Arctic contribute to wildfire weather in the western United States? Shifts in atmospheric circulation patterns, it turns out, come about through surface warming in an increasingly iceless Arctic. Watch this animation to learn more about the mechanism at play.

Animation by Sara Levine | Pacific Northwest National Laboratory

“Some say the world will end in fire,” wrote Robert Frost a century ago. The poet described one popular take on the world’s end before shifting to its apocalyptic opposite, writing, “some say in ice.”

But the relationship between fire and ice, in terms of Earth’s climate, is not quite as “either or” as Frost depicted. In the case of a study presented today at the 2021 AGU Fall Meeting in New Orleans, that relationship is more “give and take.”

The team of researchers behind the recent study published in Nature describe a link between dwindling sea ice and worsening wildfires in the western United States. As sea ice melts from July to October, sunlight warms the increasingly iceless, surrounding area. This ultimately brings heat and fire-favorable conditions to distant states like California, Washington, and Oregon later in autumn and early winter.

The researchers describe this relationship—its existence previously known, but its underlying mechanism now described for the first time—as similarly influential as climate patterns like the El Niño-Southern Oscillation.