Biologists at the University of Cincinnati found that it’s not just the size of its head and body that puts almost everything on a python’s menu. They evolved super-stretchy skin between their lower jaws that allows them to consume prey up to six times larger than similar-sized snakes.

The study, funded in part by a grant from the National Science Foundation, was published in the journal Integrative Organismal Biology.

Since most snakes swallow prey whole, they must have wide mouths to accommodate a meal. Unlike our lower jawbone, the lower jawbones of snakes are not connected, allowing them to open wide.

“The stretchy skin between left and right lower jaws is radically different in pythons. Just over 40% of their total gape area on average is from stretchy skin,” lead author and UC biology professor Bruce Jayne said. “Even after you correct for their large heads, their gape is enormous.”

Pythons are constrictors. They bite their prey and wrap their powerful coils around it, fatally cutting off the animal’s vital blood flow, before consuming it whole at their leisure.

The bigger the prey, the more energy a snake derives from a meal. For pythons, that means not having to hunt as often, which can carry extensive risk in a world full of busy roads and dangerous predators.

Along with pythons, Jayne studied the gape size of brown tree snakes, a mildly venomous arboreal specialist that hunts birds and other animals in the forest canopy. Brown tree snakes were introduced in the 1950s to Guam, wiping out many bird species.

Besides measuring the snakes, Jayne also measured the dimensions and weight of potential prey animals. This allowed Jayne to use snake size to predict the maximal size of its prey and the relative benefits of consuming different types such as alligators, chickens, rats or deer.

Small snakes derive greater benefits in relative prey mass from a modest increase in gape size, the study found. This gives python babies an early advantage in taking on a broader range of prey compared to other snakes their size, Jayne said.

Being big also helps snakes avoid becoming meals themselves. Snakes fall prey to everything from wading birds to minks and raccoons to alligators and other snakes.

“Once those pythons get to a reasonable size, it’s pretty much just alligators that can eat them,” Jayne said. “And pythons eat alligators.”

Like invasive brown tree snakes in Guam, Burmese pythons are wreaking havoc on the ecology of Everglades National Park where they were introduced due to the release of captive animals from the exotic pet trade in the 1980s.

Study co-author Ian Bartoszek works as an environmental science project manager for the Conservancy of Southwest Florida, where he has led a project to track pythons. They implant radio transmitters in male snakes during breeding season to find females before they can lay more clutches of eggs. A big female python can lay more than 100 eggs.

Researchers routinely find deer hooves and the remains of other big animals in their stomachs. Bartoszek photographed one python regurgitating a full-grown white-tailed deer.

“The Everglades ecosystem is changing in real time based on one species, the Burmese python,” Bartoszek said.

The good news is that pythons rarely attack people. Bartoszek said the only defensive encounters he’s had with wild pythons are with females guarding their nests.

“It’s way more dangerous to drive there than to work with the snakes,” he said.

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“We picked the Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples — and now we know we sent the rover to the right location,” said Thomas Zurbuchen, NASA’s associate administrator for science in Washington. “These first two science campaigns have yielded an amazing diversity of samples to bring back to Earth by the Mars Sample Return campaign.”

Twenty-eight miles (45 kilometers) wide, Jezero Crater hosts a delta — an ancient fan-shaped feature that formed about 3.5 billion years ago at the convergence of a Martian river and a lake. Perseverance is currently investigating the delta’s sedimentary rocks, formed when particles of various sizes settled in the once-watery environment. During its first science campaign, the rover explored the crater’s floor, finding igneous rock, which forms deep underground from magma or during volcanic activity at the surface.

“The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks — formed from crystallization of magma — discovered on the crater floor,” said Perseverance project scientist Ken Farley of Caltech in Pasadena, California. “This juxtaposition provides us with a rich understanding of the geologic history after the crater formed and a diverse sample suite. For example, we found a sandstone that carries grains and rock fragments created far from Jezero Crater — and a mudstone that includes intriguing organic compounds.”

“Wildcat Ridge” is the name given to a rock about 3 feet (1 meter) wide that likely formed billions of years ago as mud and fine sand settled in an evaporating saltwater lake. On July 20, the rover abraded some of the surface of Wildcat Ridge so it could analyze the area with the instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.

SHERLOC’s analysis indicates the samples feature a class of organic molecules that are spatially correlated with those of sulfate minerals. Sulfate minerals found in layers of sedimentary rock can yield significant information about the aqueous environments in which they formed.

What Is Organic Matter?

Organic molecules consist of a wide variety of compounds made primarily of carbon and usually include hydrogen and oxygen atoms. They can also contain other elements, such as nitrogen, phosphorus, and sulfur. While there are chemical processes that produce these molecules that don’t require life, some of these compounds are the chemical building blocks of life. The presence of these specific molecules is considered to be a potential biosignature — a substance or structure that could be evidence of past life but may also have been produced without the presence of life.

In 2013, NASA’s Curiosity Mars rover found evidence of organic matter in rock-powder samples, and Perseverance has detected organics in Jezero Crater before. But unlike that previous discovery, this latest detection was made in an area where, in the distant past, sediment and salts were deposited into a lake under conditions in which life could potentially have existed. In its analysis of Wildcat Ridge, the SHERLOC instrument registered the most abundant organic detections on the mission to date.

“In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could potentially have thrived,” said Farley. “The fact the organic matter was found in such a sedimentary rock — known for preserving fossils of ancient life here on Earth — is important. However, as capable as our instruments aboard Perseverance are, further conclusions regarding what is contained in the Wildcat Ridge sample will have to wait until it’s returned to Earth for in-depth study as part of the agency’s Mars Sample Return campaign.”

The first step in the NASA-ESA (European Space Agency) Mars Sample Return campaign began when Perseverance cored its first rock sample in September 2021. Along with its rock-core samples, the rover has collected one atmospheric sample and two witness tubes, all of which are stored in the rover’s belly.

The geologic diversity of the samples already carried in the rover is so good that the rover team is looking into depositing select tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its delta explorations.

“I’ve studied Martian habitability and geology for much of my career and know first-hand the incredible scientific value of returning a carefully collected set of Mars rocks to Earth,” said Laurie Leshin, director of NASA’s Jet Propulsion Laboratory in Southern California. “That we are weeks from deploying Perseverance’s fascinating samples and mere years from bringing them to Earth so scientists can study them in exquisite detail is truly phenomenal. We will learn so much.”

More About the Mission

A key objective for Perseverance’s mission on Mars is astrobiology, including caching samples that may contain signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent NASA missions, in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech, built and manages operations of the Perseverance rover.

For more about Perseverance: https://mars.nasa.gov/mars2020/

The default mode network (DMN), which comprises the posterior medial cortex, medial prefrontal cortex, and lateral temporal-parietal regions, has been shown to be engaged in several task-related behaviors. Studies show that DMN activity increases during inward-directed thought and decreases during externally directed tasks requiring focused attention. Despite evidence for a role for the DMN in shaping behavior, little is known about how task-related changes in the DMN influence connectivity with other brain regions. For example, while some observations indicate an indirect relationship between the DMN and the striatum, how the DMN and striatum interact during tasks remains unclear.

To further explore the functions of the DMN, Drs. Dobryakova and Smith applied a novel analysis to the reward task, using behavioral and neuroimaging data from 495 randomly selected individuals in the Human Connectome Project, an open access database of healthy participants. The goals of this network-based psycho-physiological interaction analysis were twofold, according to Dr. Dobryakova, a senior research scientist in the Foundation’s Center for Traumatic Brain Injury Research. “First, to test the effects of reward on connectivity between the DMN and the striatum; and second, whether such connectivity is associated with behavioral and personality characteristics relevant to reward processing,” she explained.

In line with other studies, during the task, they observed decreased activation of the DMN and relative increased activation of other networks. “Most notably, we found that the experience of reward enhanced connectivity between the DMN and the ventral striatum,” Dr. Dobryakova reported, “an effect specific to the DMN. We were also surprised that the strength of this connectivity correlated with personality characteristics relating to openness,” she added.

Greater understanding of the workings of the healthy brain will influence future research and care for individuals with neuropsychiatric syndromes. “Improving our understanding of the interaction of the DMN with other brain networks has the potential to aid clinical research into better treatments for common syndromes such as depression, substance abuse, and schizophrenia,” Dr. Dobryakova concluded.

This research was supported by grants from the National Institutes of Health grants R21-MH113917 (DVS), R03-DA046733 (DVS), RF1-AG067011 (DVS), R01-NS121107 (ED).

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Published in the Cell Press journal iScience, Deep learning models fail to capture the configural nature of human shape perception is a collaborative study by Elder, who holds the York Research Chair in Human and Computer Vision and is Co-Director of York’s Centre for AI & Society, and Assistant Psychology Professor Nicholas Baker at Loyola College in Chicago, a former VISTA postdoctoral fellow at York.

The study employed novel visual stimuli called “Frankensteins” to explore how the human brain and DCNNs process holistic, configural object properties.

“Frankensteins are simply objects that have been taken apart and put back together the wrong way around,” says Elder. “As a result, they have all the right local features, but in the wrong places.”

The investigators found that while the human visual system is confused by Frankensteins, DCNNs are not — revealing an insensitivity to configural object properties.

“Our results explain why deep AI models fail under certain conditions and point to the need to consider tasks beyond object recognition in order to understand visual processing in the brain,” Elder says. “These deep models tend to take ‘shortcuts’ when solving complex recognition tasks. While these shortcuts may work in many cases, they can be dangerous in some of the real-world AI applications we are currently working on with our industry and government partners,” Elder points out.

One such application is traffic video safety systems: “The objects in a busy traffic scene — the vehicles, bicycles and pedestrians — obstruct each other and arrive at the eye of a driver as a jumble of disconnected fragments,” explains Elder. “The brain needs to correctly group those fragments to identify the correct categories and locations of the objects. An AI system for traffic safety monitoring that is only able to perceive the fragments individually will fail at this task, potentially misunderstanding risks to vulnerable road users.”

According to the researchers, modifications to training and architecture aimed at making networks more brain-like did not lead to configural processing, and none of the networks were able to accurately predict trial-by-trial human object judgements. “We speculate that to match human configural sensitivity, networks must be trained to solve broader range of object tasks beyond category recognition,” notes Elder.

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The approach proved more than 90% accurate at predicting outcomes among more than two dozen patients in the intensive care unit at UVA and 100 patients from publicly available data generated at Duke and Harvard. The test, called CovGENE, analyzes genes expressed in a person’s blood to determine whether they may experience a severe disease course with increased risk of death.

“We have come far in the prevention and treatment of COVID-19 in the past two years. Regardless, we still struggle to identify patients at highest risk for severe disease. Our study uses a gene-analysis approach to identify an immune cell signature, distinct from other respiratory illnesses, that correlates with worse outcomes,” said researcher Alexandra Kadl, MD, of UVA Health’s Division of Pulmonary and Critical Care Medicine. “This knowledge has the potential to help evaluate patients’ immune profile with commonly, readily available assays to identify patients at risk for bad outcomes who would benefit from closer monitoring and advanced therapies to aid their recovery.”

Predicting COVID-19 Severity

Based on the promising results of the UVA research, CovGENE’s developer, AMPEL Biosolutions, is seeking to partner with a diagnostic testing company or pharmaceutical company to bring the approach to market as a simple PCR-based blood test.

“This unique collaboration with our colleagues from the University of Virginia has provided an easy and novel means to assess an individual patient’s response to the SARS-CoV-2 virus and predict the clinical outcome,” said Peter Lipsky, MD, AMPEL’s CEO, chief medical officer and co-founder. “Now that this unique approach has been validated, we look forward to its rapid development as a precision-medicine tool that can improve the outcome of patients with COVID-19 and reduce the number of hospitalizations, especially the most vulnerable.”

AMPEL Biosolutions aims to use genomic data to improve healthcare for patients. The company develops gene expression tests for blood or tissue samples to assist doctors in clinical decision-making.

Company co-founder Amrie Grammer, PhD, is an alumna of UVA, having received both her bachelor’s and master’s degree there.

Findings Published

The researchers have published their findings in the journal Frontiers in Immunology. The team consisted of Andrea R. Daamen, Prathyusha Bachali, Catherine A. Bonham, Lindsay Somerville, Jeffrey M. Sturek, Amrie Grammer, Alexandra Kadl and Peter Lipsky. Daamen, Bachali, Grammer and Lipsky are employed by AMPEL BioSolutions.

The work was supported by the National Institutes of Health’s National Heart Lung Blood Institute, grant K23 HL143135; the National Institute of Allergy and Infectious Diseases, grant 1R21AI160334; the COVID-19 Rapid Response Initiative by UVA’s Global Infectious Disease Institute; and The RILITE Foundation.

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Both infection and vaccination against SARS-CoV-2 contribute to building a population’s immunity to the virus — an important factor for deciding when and to whom booster shots should be offered. Although immunity against a pathogen is more than antibodies, the easiest strategy for assessing population immunity is to perform seroepidemiological studies (i.e., quantifying virus-specific antibodies in a given population group).

“Most of the serological studies performed after COVID-19 vaccination focused on specific groups such as healthcare workers, did not distinguish between people with or without previous infection, or did not have clinical and immunological data of the infection,” explains Manolis Kogevinas, ISGlobal researcher and senior co-author of the study together with Carlota Dobaño, also researcher at ISGlobal.

In this study, the research team performed a second measurement in a population-based cohort from Catalonia (COVICAT study — GCAT cohort) six months after the start of the vaccination campaign (the first one was just after the first confinement), to monitor the level and type of antibodies against five viral antigens (the whole Spike (S) protein, the RBD receptor binding domain, the S2 fragment, the full nucleocaspid (N) protein, or the N-terminal fragment). They also used information from a questionnaire and health records to identify potential factors that determine the magnitude and duration of the antibody response in unvaccinated, vaccinated, or vaccinated and infected persons. A total of 1,076 people, aged 43 to 72 years, were included in the analysis.

The results yielded three main conclusions: First, that in 36% of infected but unvaccinated persons, antibodies were no longer detectable almost a year after the infection, particularly in those older than 60 years and smokers.

Second, that vaccination induced significantly higher antibody levels in people who had a prior infection, as compared to those without prior infection; and that these levels were strongly associated with the magnitude of the response during the infection. “Our data underscore the importance of vaccinating people even if they have been previously infected, and confirm that hybrid immunity is superior and more durable. This means that people who have been vaccinated but have not been infected would need a booster earlier than those who have,” points out Marianna Karachaliou, first author of the study together with Gemma Moncunill.

Third, the factor most strongly associated with the level of antibodies is the type of vaccine — Moderna’s Spikevax generated the highest levels of antibodies. Other factors also appear to play a role: people older than 60 or with mental illness had lower antibody levels post-vaccination. “The association between mental health and antibody responses requires further investigation, but it is known that people with disorders such as depression, chronic stress or schizophrenia have a lower response to vaccination in general,” explains Dobaño.

Among those vaccinated, only 2.1% had no antibodies at the time of testing and approximately 1% had a breakthrough infection. “However, it should be noted that this study was done before the Omicron variant became dominant,” warns Kogevinas.

They have just published the results of their study in the journal Frontiers in Bioengineering and Biotechnology. During normal breathing, the diaphragm descends below the lungs with each breath. This causes the lungs to expand inside the chest, creating a negative pressure, or vacuum, in the lungs. To compensate for this negative pressure, air automatically flows into the lungs and the person breathes in. Mechanical ventilation involves pumping air into the lungs through a tube. The lungs then expand due to this positive pressure. “We assume that this positive pressure causes a slight compression of the lung tissue, whereas during normal breathing the lung is ‘pulled’ from the outside in order to create the expansion,” explains physicist Professor Mareike Zink, who conducted the interdisciplinary study on the physics of the premature lung together with her colleague Dr Mandy Laube from the neonatology research laboratory at the Faculty of Medicine.

“In our experiments, we studied foetal lung tissue under tensile and compressive stress to explore differences in tissue mechanics in the premature lung,” Mareike Zink reports. The experiments showed that the lung tissue deformed completely elastically under tension, as occurs during normal breathing. When subjected to pressure, however — as occurs with mechanical ventilation — viscoelastic deformation of the lungs was observed. This means that although the tissue returns to its original state after deformation, at the molecular level, there are already structural changes that indicate irreversible tissue damage.

“Furthermore, our results show that lung cell function is impaired under pressure. Even low pressure, as is common in mechanical ventilation, can result in structural units on the cell surface, which are important in the transport of molecules and water, for example, no longer being able to perform their function,” explains Mandy Laube.

The two scientists draw the following conclusion: for some premature infants, mechanical ventilation is the only treatment to ensure survival. Nevertheless, there is a risk of complications due to the altered mechanical properties of premature lungs compared to adults. Future therapeutic strategies should therefore consider the influence of physical forces on tissues and cells, and limit pressure increases in the lungs so as to minimise the risk of damage. “Since it has also been observed in ventilated Covid-19 patients that mechanical ventilation may result in further lung damage, we postulate that here, too, the damaged lung can be more easily overstretched by the positive pressure and that lung cell function stops or changes more quickly under increased pressure,” Mareike Zink concludes.

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Materials provided by Universität Leipzig. Original written by Susann Huster. Note: Content may be edited for style and length.