The Cow, Around the Cosmic Explosion (Astronomy)

Using the Giant Metrewave Radio Telescope (uGmrt), in India, two scientists discovered that At 2018 – also known as “the cow” – presents an extremely inhomogeneous environment. This is the first observational evidence of inhomogeneous emission from an Fbot. All the details on ApJ Letters

Two astronomers from the National Center for radio Astrophysics at the Tata Institute of Fundamental Research (Ncra-Tifr) in Pune, using the Giant Metrewave Radio Telescope (uGmrt), found that At 2018 – for friends, the cow – presents an extremely inhomogeneous environment. . This object is the first of a class of recently discovered cosmic explosions known as Fast Blue Optical Transient (Fbot). They are sources that release an enormous amount of energy but which vanish very quickly. This, together with their extremely blue color, led to them being called Fbots. The discovery, published in The Astrophysical Journal Letters, represents the first observational evidence of inhomogeneous emission of an Fbot . The origins of Fbots are still under discussion, but proposed models include the explosion of a massive star, the collision of an accreting neutron star with another star, or the merger of two white dwarfs .

Precisely because they appear and disappear very quickly, Fbots are difficult to find. Many of them have been discovered in recent years thanks to the advent of surveys that scan the sky almost daily. Fbots that also emit in radio are even rarer, but they are particularly interesting because radio observations help determine the properties of the environments of these explosions and their ancestors.

At 2018cow was discovered on June 16, 2018. At a distance of about 215 million light years, “the cow” showed much greater brightness than normal supernovae . The two authors of the study, Poonam Chandra and AJ Nayana , carried out radio observations of At 2018cow with the uGmrt to determine the properties of its extended environment and region of emission. “Our studio benefited enormously from the uGmrt’s unique low frequency capabilities. The cow’s uGmrt observationsthey played a unique role in highlighting the non-uniform density around this explosion, ”explains Nayana, adding:“ Our work provides the first observational evidence of inhomogeneous emission from an Fbot. The density of the material around this explosion drops dramatically to around 0.1 light-years from the transient. This indicates that the progenitor star of At 2018cow, towards the end of its life cycle, was losing mass much faster ».

The solid / dashed green and red lines indicate different theoretical patterns. 
The point of inversion of this light curve allowed the determination of the velocity of the ejected material, the intensity of the magnetic field and the density of the environment at different distances from the center of the explosion. Credits: AJ Nayana and Poonam Chandra

At 2018cow is also unusual because it has been on the radio for a long time. The longer the post-explosion emission can be observed, the greater the distance traveled by the ejected material during the explosion. This allows studying the source environment on a large scale. The authors observed the cowfor about 2 years with the uGmrt, to understand its properties. “This is the first Fbot seen for so long at low radio frequencies and the uGmrt data has provided crucial information about the environment of this transient,” continues Nayana. “That’s the beauty of low-frequency radio observations: you get to trace the footprints of the parent system long before it explodes. It is interesting that the material of the explosion moves with a speed greater than 20 percent of the speed of light even after about 257 days after the explosion, without any deceleration, ”adds Poonam Chandra.

While the origin of Fbots is still under debate, detailed radio observations can provide some insight into various physical parameters of these events, such as the speed of the material that escaped from this explosion, the strength of the magnetic field, and the rate at which the parent system loses. mass before the explosion. UGmrt observations from At 2018cow suggest that the progenitor ejected its material about 100 times faster during the years near the end of its life than it did about 23 years before the explosion. Furthermore, At 2018cow showed inhomogeneity in the radio emission region while the other two radio Fbots did not show these properties, making the cowunique in its group. “The observations of multiple Fbots with the uGmrt will provide information on their environments and ancestors, to develop a complete picture of the properties of these intriguing transients,” concludes Nayana.

Featured image: Artist’s impression of a fast and blue optical transient. Credits: Bill Saxton, Nrao / Aui / Nsf


To know more:


Provided by INAF

Inside Saturn it Rains Liquid Helium (Planetary Science)

New simulations of the planet’s interior conducted by two researchers from Johns Hopkins University have shown some peculiar details about the functioning of its magnetic field: it is influenced by a thick layer of helium rain present in the innermost regions. The results are published in Agu Advances

Saturn is made up of layers, like ogres and onions: on the outside it has a gaseous atmosphere, mostly made of hydrogen, but on the inside, going towards the core, the increasing pressures and increasing temperatures lead this gas to behaviors that here on Earth we would consider them unusual . Below the atmosphere is a thick layer of molecular hydrogen that surrounds one made up mostly of helium. If you go even deeper you will find the so-called metallic hydrogen, a state of matter in which hydrogen atoms are so compact that they are essentially protons immersed in a sea of ​​free-to-move electrons. Then there is the inner core, rocky and solid. The details of the internal structure of a gas giant remain, however, always shrouded in mystery, because what happens in the heart of these planetary monsters, on which matter takes on forms and structures that we have never seen here on Earth and that we can hardly reproduce in the laboratory. , is well concealed and complex.

Computational simulations come to the aid , made more and more sophisticated and detailed by the growing computing power available: some initial characteristics are imposed on the virtual planet and it is observed whether, by describing its evolution through physical models, the simulation is able to reproduce this. that we observe. If it is able to do this, the models describe reality well, if it is not they are probably to be discarded or modified.

A pair of Johns Hopkins University researchers, Chi Yan and Sabine Stanley , have worked out complex simulations of Saturn’s interior and magnetic field, uncovering intriguing details. These simulations used the data of the Cassini probe , which from 1997 to 2017 observed the Lord of the Rings relentlessly, obtaining, among the many data, also a lot of information about the magnetic field.

It is the layer of metallic hydrogen that is responsible for the magnetic field of Saturn: for a planetary magnetic field it is necessary that there is a conducting fluid in rotation and the metallic hydrogen, thanks to the sea of ​​free electrons, conducts very well. But the magnetic field of Saturn is particular among the planets of the solar system, because it is almost perfectly symmetrical around the axis of rotation and the geographic north pole and the magnetic one are substantially coincident. The researchers investigated what ingredients were needed to produce Saturn’s magnetic field in the structure observed in the Cassini data . The most intriguing discovery is the presence ofa sort of rain of liquid helium that could affect the Saturnian magnetic field by modifying it . The temperature at the top of this layer, the researchers identified, is slightly variable, higher at the equator, lower at the poles.

But there is also something in the study’s findings that may not return: the authors have found small asymmetries in the polar regions of the magnetic field, aspects that will require further in-depth analysis of the polar regions.

These studies are not only interesting for Saturn: «By studying how Saturn was formed and how it evolved over time», says Stanley, the second author of the study, «we can learn a lot about the formation of other Saturn-like planets in our solar system, but also elsewhere ».

Featured image: The stratification of the interior of Saturn. Credits: Yi Zheng (Hemi / Mica Extreme Arts Program)


To know more:


Provided by INAF

Hollings Researchers Study SARS-CoV-2 Antibodies in Asymptomatic & Symptomatic Individuals (Medicine)

MUSC Hollings Cancer Center researchers added to the understanding of the protective immune response against the SARS-CoV-2 virus in a study published in April in iScience. The team found that approximately 3% of the population is asymptomatic, which means that their bodies can get rid of the virus without developing signs of illness.

The researchers screened more than 60,000 blood samples from symptomless individuals in the Southeastern U.S., including Georgia, South Carolina and North Carolina, for the IgG antibody to the viral spike protein.

What began as a highly collaborative statewide effort to detect SARS-CoV-2 accurately, when tests were lacking, has led to discoveries. Last year, Shikhar Mehrotra, Ph.D., professor, and scientific director of the FACT-accredited Clean Cell Therapy Unit at MUSC, led the task of developing a method to detect COVID-19 infections rapidly in patients.

The research team developed an orthogonal ELISA-based serological assay, which allows for large-scale antibody testing. While commercial antibody tests are now more readily available, the work has excellent strength in findings because of the exceptionally large sample size, said Mehrotra. Studies such as this shed light on the current unknowns, such as the longevity of the antibodies, their ability to protect from repeat infections and the protective concentration (titer) of neutralizing antibodies.

“Research across the biomedical research spectrum over the last year has demonstrated how public health can be accelerated by collaboration from all sectors, including academic, pharmaceutical and regulatory agencies.”

— Dr. Shikhar Mehrotra

“As cancer researchers who focus on understanding the role of the immune system in cancer, we are well-positioned to tackle the difficult immunity questions raised by COVID-19. This work was a concerted effort with the highly skilled scientists in the Clean Cell Facility who processed this large sample population,” said Mehrotra.

Disease-specific antibody research is necessary to understand protective immunity and understand more fully the prevalence of infection and immune responses to both the virus and vaccines. The team found that high levels of anti-S IgG, the antibody that detects the spike protein, and anti-RBD IgG, the antibody that detects the receptor-binding domain of the spike protein, strongly correlated with neutralizing activity, meaning they defend the person from the virus. Antibodies from 94 hospitalized COVID-19 patients were also assessed: the data showed that compared to asymptomatic individuals with high anti-S IgG, sick patients had decreased antibody responses and reduced neutralizing activity.

The data showed that younger (30 years old and younger) versus older individuals had the highest antibody responses. Also, the findings matched other reports indicating that COVID-19 is disproportionately high in African Americans in Southeastern states.

In the future, this tool can be used to monitor antibody levels upon vaccination or as a screening tool for therapeutic convalescent plasma. Since analyzing neutralizing antibodies in all patients and asymptomatic individuals is challenging, the results indicate that IgG anti-S or RBD can act as a surrogate in determining neutralizing activity in individuals tested for SARS-CoV-2 infection or vaccine response.

More studies are needed to understand the differences between neutralizing antibodies in asymptomatic and hospitalized individuals. Follow-up studies can be done with this extensive data set; for example, the biomarkers between asymptomatic and symptomatic individuals can be compared.

The increase in cross-disciplinary research reveals how novel strategies can accelerate research across medical subdisciplines. The development of mRNA-based COVID vaccines is anticipated to boost cancer research developments. For two decades, scientists have been trying to use RNA as a therapeutic but with little success, since RNA naturally degrades quickly. Now, with the COVID vaccines, it is apparent that stabilizing techniques are feasible and can be translated to other applications, such as cancer vaccines targeting markers on cancer cells or epitopes.

Identifying disease prevalence as a whole helps public health leaders to target interventions and prioritize resources. “Research across the biomedical research spectrum over the last year has demonstrated how public health can be accelerated by collaboration from all sectors, including academic, pharmaceutical and regulatory agencies,” said Mehrotra.

Funding support from the MUSC President’s Office for COVID-19 research, South Carolina Clinical & Translational Research Award and in part by NIH R01CA138930 and R01CA250458.

Featured image: Dr. Shikhar Mehrotra’s team analyzed more than 60,000 blood samples as part of their large-scale COVID-19 antibody study. Photo by Marquel Coaxum


Reference: Connor J. Dwyer, Colleen A. Cloud et al., “Comparative Analysis of Antibodies to SARS-CoV-2 between Asymptomatic and Convalescent Patients”, iScience, 2021. DOI: https://doi.org/10.1016/j.isci.2021.102489


Provided by Medical University of South California

COVID-19 Vaccine is Associated With Fewer Asymptomatic SARS-CoV-2 Infections (Medicine)

St. Jude Children’s Research Hospital COVID-19 screening and vaccination program for employees offers early evidence that vaccine protects against asymptomatic infection, which has fueled the pandemic.

Vaccination dramatically reduced COVID-19 symptomatic and asymptomatic infections in St. Jude Children’s Research Hospital employees compared with their unvaccinated peers, according to a research letter that appears today in the Journal of the American Medical Association.

The study is among the first to show an association between COVID-19 vaccination and fewer asymptomatic infections. When the Pfizer-BioNTech BNT162b2 vaccine was authorized for use in the U.S., the vaccine was reported to be highly effective at preventing laboratory-confirmed COVID-19. Clinical trial data suggested that the two-dose regimen reduced symptomatic disease, including hospitalization and death. But an association with reduced asymptomatic infection was unclear.

“While further research is needed, by preventing infections, including in people who have no symptoms, there is a high possibility that vaccination will decrease transmission of SARS-CoV-2,” said Diego Hijano, M.D., of the St. Jude Department of Infectious Diseases. He and Li Tang, Ph.D., of St. Jude Biostatistics, are the first authors of the report. Tang is also the corresponding author.

The study involved 5,217 St. Jude employees who were eligible under Tennessee state guidelines for vaccination between Dec. 17, 2020, and March 20, 2021. More than 58% of employees were vaccinated during that period. Most workers received both doses.

Overall, vaccination reduced the risk of asymptomatic and symptomatic SARS-CoV-2 infection by 79% in vaccinated employees compared with their unvaccinated colleagues. An analysis of asymptomatic infections alone found vaccination reduced the risk by 72%.   

Protection was even greater for employees who completed two doses. A week or more after receiving the second dose, vaccinated employees were 96% less likely than unvaccinated workers to become infected with SARS-CoV-2. When researchers looked just at asymptomatic infections, vaccination reduced the risk by 90%.

Finding SARS-CoV-2 infections

First author Li Tang, Ph.D., of St. Jude Biostatistics, contributed to the study that is published in the Journal of the American Medical Association. © St. Jude

The research stems from a program that St. Jude leaders began in March 2020 to protect patients and employees from the pandemic virus.

The effort included targeted testing for employees with COVID-19 symptoms or known exposure to the pandemic virus. The plan also involved routine, laboratory testing of asymptomatic employees. Nasal swabs were collected at least weekly from self-reported asymptomatic on-campus workers to perform polymerase chain reaction to detect asymptomatic SARS-CoV-2 infection.

“This study was possible because St. Jude invested in resources to determine how best to control the disease and protect our patients and employees,” Tang said. “Few places then or now provide such broad asymptomatic testing.”

Hijano said, “Testing has been invaluable to the institutional COVID-19 mitigation plan. In the end, the testing also serves as a unique tool that helps to fill in critical knowledge gaps.”

Results by the numbers

During the study, 236 of the 5,217 employees included in the analysis tested positive for SARS-CoV-2. They included 185 unvaccinated employees and 51 of the 3,052 workers who had received at least one dose of the vaccine.

Almost half of the positive cases, 108, reported no symptoms upon testing. The asymptomatic cases included 20 employees who had received one vaccine dose and three who tested positive within seven days of the second dose. “The results are a reminder of the many hidden cases in the population, which makes containing the virus a big challenge,” Tang said.

The study group included a cross-section of employees in regard to race and gender. More than 80% of employees were younger than 65 years old. The vaccinated group included a higher percentage of health care staff, 47%, than the unvaccinated employees, 25.7%.

Authors and funding

The senior authors are James Hoffman, Pharm.D., and Randall Hayden, M.D., of St. Jude. The other authors are Aditya Gaur, Terrence Geiger and Ellis Neufeld, all of St. Jude.

The research was funded in part by ALSAC, the St. Jude fundraising and awareness organization.

Featured image: First author Diego Hijano, M.D., of the St. Jude Department of Infectious Diseases, studied how the COVID-19 vaccine reduced symptomatic and asymptomatic infections in employees. © St. Jude

Read the full text of the article:

Asymptomatic and Symptomatic SARS-CoV-2 Infections after BNT162b2 Vaccination in a Routinely Screened Workforce. Journal of the American Medical Association, Published May 6, 2021.


Provided by St. Jude Children’s Research Hospital

The Cerebellum May Have Played an Important Role in the Evolution of the Human Brain (Neuroscience)

Study compares epigenetic modifications to DNA in the cerebellum of humans, chimpanzees and monkeys

The cerebellum–a part of the brain once recognized mainly for its role in coordinating movement–underwent evolutionary changes that may have contributed to human culture, language and tool use. This new finding appears in a study by Elaine Guevara of Duke University and colleagues, published May 6th in the journal PLOS Genetics.

Scientists studying how humans evolved their remarkable capacity to think and learn have frequently focused on the prefrontal cortex, a part of the brain vital for executive functions, like moral reasoning and decision making. But recently, the cerebellum has begun receiving more attention for its role in human cognition. Guevara and her team investigated the evolution of the cerebellum and the prefrontal cortex by looking for molecular differences between humans, chimpanzees, and rhesus macaque monkeys. Specifically, they examined genomes from the two types of brain tissue in the three species to find epigenetic differences. These are modifications that do not change the DNA sequence but can affect which genes are turned on and off and can be inherited by future generations.

Compared to chimpanzees and rhesus macaques, humans showed greater epigenetic differences in the cerebellum than the prefrontal cortex, highlighting the importance of the cerebellum in human brain evolution. The epigenetic differences were especially apparent on genes involved in brain development, brain inflammation, fat metabolism and synaptic plasticity–the strengthening or weakening of connections between neurons depending on how often they are used.

The epigenetic differences identified in the new study are relevant for understanding how the human brain functions and its ability to adapt and make new connections. These epigenetic differences may also be involved in aging and disease. Previous studies have shown that epigenetic differences between humans and chimpanzees in the prefrontal cortex are associated with genes involved in psychiatric conditions and neurodegeneration. Overall, the new study affirms the importance of including the cerebellum when studying how the human brain evolved.

Guevara adds, “Our results support an important role for the cerebellum in human brain evolution and suggest that previously identified epigenetic features distinguishing the human neocortex are not unique to the neocortex.”

Funding: The work was supported by funding from the Center for the Advanced Study of Human Paleobiology at The George Washington University (https://cashp.columbian.gwu.edu/) to CCS and EEG, Duke University Department of Evolutionary Anthropology to EEG (https://evolutionaryanthropology.duke.edu/), the James S. McDonnell Foundation (https://www.jsmf.org/) Grant #220020293 to CCS, and National Science Foundation (https://www.nsf.gov/) Grants SMA-1542848 to CCS, WDH, and BJB; EF-2021785 to CCS, and BSC-1919780 to CCS and EEG. The National Chimpanzee Brain Resource was supported by National Institutes of Health (https://www.nih.gov/) Grant NS092988 to CCS and WDH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


Reference: Guevara EE, Hopkins WD, Hof PR, Ely JJ, Bradley BJ, Sherwood CC (2021) Comparative analysis reveals distinctive epigenetic features of the human cerebellum. PLoS Genet 17(5): e1009506. https://doi.org/10.1371/journal.pgen.1009506


Provided by PLOS

Ancient DNA Reveals Origin Of First Bronze Age Civilizations in Europe (Archeology)

Finding shed light on role of migration in Neolithic to Bronze Age transition and emergence of Indo-European languages

The first civilisations to build monumental palaces and urban centres in Europe are more genetically homogenous than expected, according to the first study to sequence whole genomes gathered from ancient archaeological sites around the Aegean Sea. The study has been published in the journal Cell.

Despite marked differences in burial customs, architecture, and art, the Minoan civilization in Crete, the Helladic civilization in mainland Greece and the Cycladic civilization in the Cycladic islands in the middle of the Aegean Sea, were genetically similar during the Early Bronze age (5000 years ago).

The findings are important because it suggests that critical innovations such as the development of urban centres, metal use and intensive trade made during the transition from the Neolithic to the Bronze Age were not just due to mass immigration from east of the Aegean as previously thought, but also from the cultural continuity of local Neolithic groups.

The study also finds that by the Middle Bronze Age (4000-4,600 years ago), individuals from the northern Aegean were considerably different compared to those in the Early Bronze Age. These individuals shared half their ancestry with people from the Pontic-Caspian steppe, a large geographic region stretching between the Danube and the Ural rivers and north of the Black Sea, and were highly similar to present-day Greeks.

The findings suggest that migration waves from herders from the Pontic-Caspian steppe, or populations north of the Aegean that bear Pontic-Caspian Steppe like ancestry, shaped present-day Greece. These potential migration waves all predate the appearance of the earliest documented form of Greek, supporting theories explaining the emergence of Proto-Greek and the evolution of Indo-European languages in either Anatolia or the Pontic-Caspian Steppe region.

The team took samples from well-preserved skeletal remains at archaeological sites. They sequenced six whole genomes, four from all three cultures during the Early Bronze Age and two from a Helladic culture during the Middle Bronze Age.

The researchers also sequenced the mitochondrial genomes from eleven other individuals from the Early Bronze Age. Sequencing whole genomes provided the researchers with enough data to perform demographic and statistical analyses on population histories.

Sequencing ancient genomes is a huge challenge, particularly due to the degradation of the biological material and human contamination. A research team at the CNAG-CRG, played an important role in overcoming this challenge through using machine learning.

According to Oscar Lao, Head of the Population Genomics Group at the CNAG-CRG, “Taking an advantage that the number of samples and DNA quality we found is huge for this type of study, we have developed sophisticated machine learning tools to overcome challenges such as low depth of coverage, damage, and modern human contamination, opening the door for the application of artificial intelligence to palaeogenomics data.”

“Implementation of deep learning in demographic inference based on ancient samples allowed us to reconstruct ancestral relationships between ancient populations and reliably infer the amount and timing of massive migration events that marked the cultural transition from Neolithic to Bronze Age in Aegean,” says Olga Dolgova, postdoctoral researcher in the Population Genomics Group at the CNAG-CRG.

The Bronze Age in Eurasia was marked by pivotal changes on the social, political, and economic levels, visible in the appearance of the first large urban centres and monumental palaces. The increasing economic and cultural exchange that developed during this time laid the groundwork for modern economic systems–including capitalism, long-distance political treaties, and a world trade economy.

Despite their importance for understanding the rise of European civilisations and the spread of Indo-European languages, the genetic origins of the peoples behind the Neolithic to Bronze Age transition and their contribution to the present-day Greek population remain controversial.

Future studies could investigate whole genomes between the Mesolithic and Bronze Age in the Armenian and Caucasus to help further pinpoint the origins of migration into the Aegean, and to better integrate the genomic data with the existing archaeological and linguistic evidence.

Featured image: Skeleton of one of the two individuals who lived in the middle of the Bronze Age and whose complete genome was reconstructed and sequenced by the Lausanne team. It comes from the archaeological site of Elati-Logkas, in northern Greece. © Ephorate of Antiquities of Kozani, Hellenic Ministry of Culture, Greece. Courtesy of Dr Georgia Karamitrou-Mentessidi.


Reference: Florian Clemente, Martina Unterländer et al., “The genomic history of the Aegean palatial civilizations”, Cell, 2021. DOI: https://doi.org/10.1016/j.cell.2021.03.039


Provided by Center for Genomic Regulation

Review: Most Human Origins Stories Are Not Compatible With Known Fossils (Paleontology)

Fossil apes can inform us about essential aspects of ape and human evolution, including the nature of our last common ancestor

In the 150 years since Charles Darwin speculated that humans originated in Africa, the number of species in the human family tree has exploded, but so has the level of dispute concerning early human evolution. Fossil apes are often at the center of the debate, with some scientists dismissing their importance to the origins of the human lineage (the “hominins”), and others conferring them starring evolutionary roles. A new review out on May 7 in the journal Science looks at the major discoveries in hominin origins since Darwin’s works and argues that fossil apes can inform us about essential aspects of ape and human evolution, including the nature of our last common ancestor.

Humans diverged from apes–specifically, the chimpanzee lineage–at some point between about 9.3 million and 6.5 million years ago, towards the end of the Miocene epoch. To understand hominin origins, paleoanthropologists aim to reconstruct the physical characteristics, behavior, and environment of the last common ancestor of humans and chimps.

“When you look at the narrative for hominin origins, it’s just a big mess–there’s no consensus whatsoever,” said Sergio Almécija, a senior research scientist in the American Museum of Natural History’s Division of Anthropology and the lead author of the review. “People are working under completely different paradigms, and that’s something that I don’t see happening in other fields of science.”

There are two major approaches to resolving the human origins problem: “Top-down,” which relies on analysis of living apes, especially chimpanzees; and “bottom-up,” which puts importance on the larger tree of mostly extinct apes. For example, some scientists assume that hominins originated from a chimp-like knuckle-walking ancestor. Others argue that the human lineage originated from an ancestor more closely resembling, in some features, some of the strange Miocene apes.

In reviewing the studies surrounding these diverging approaches, Almécija and colleagues with expertise ranging from paleontology to functional morphology and phylogenetics discuss the limitations of relying exclusively on one of these opposing approaches to the hominin origins problem. “Top-down” studies sometimes ignore the reality that living apes (humans, chimpanzees, gorillas, orangutans, and hylobatids) are just the survivors of a much larger, and now mostly extinct, group. On the other hand, studies based on the “bottom-up”approach are prone to giving individual fossil apes an important evolutionary role that fits a preexisting narrative.

“In The Descent of Man in 1871, Darwin speculated that humans originated in Africa from an ancestor different from any living species. However, he remained cautious given the scarcity of fossils at the time,” Almécija said. “One hundred fifty years later, possible hominins–approaching the time of the human-chimpanzee divergence–have been found in eastern and central Africa, and some claim even in Europe. In addition, more than 50 fossil ape genera are now documented across Africa and Eurasia. However, many of these fossils show mosaic combinations of features that do not match expectations for ancient representatives of the modern ape and human lineages. As a consequence, there is no scientific consensus on the evolutionary role played by these fossil apes.”

Overall, the researchers found that most stories of human origins are not compatible with the fossils that we have today.

“Living ape species are specialized species, relicts of a much larger group of now extinct apes. When we consider all evidence–that is, both living and fossil apes and hominins–it is clear that a human evolutionary story based on the few ape species currently alive is missing much of the bigger picture,” said study co-author Ashley Hammond, an assistant curator in the Museum’s Division of Anthropology.

Kelsey Pugh, a Museum postdoctoral fellow and study co-author adds, “The unique and sometimes unexpected features and combinations of features observed among fossil apes, which often differ from those of living apes, are necessary to untangle which features hominins inherited from our ape ancestors and which are unique to our lineage.”

Living apes alone, the authors conclude, offer insufficient evidence. “Current disparate theories regarding ape and human evolution would be much more informed if, together with early hominins and living apes, Miocene apes were also included in the equation,” says Almécija. “In other words, fossil apes are essential to reconstruct the ‘starting point’ from which humans and chimpanzees evolved.”

This study was part of a collaborative effort with colleagues from the New York Institute of Technology (Nathan Thompson) and the Catalan Institute of Paleontology Miquel Crusafont (David Alba and Salvador Moyà-Solà).

Featured image: The last common ancestor of chimpanzees and humans represents the starting point of human and chimpanzee evolution. Fossil apes play an essential role when it comes to reconstructing the nature of our ape ancestry. Printed with permission from © Christopher M. Smith


Reference: Sergio Almécija, Ashley S. Hammond, Nathan E. Thompson, Kelsey D. Pugh, Salvador Moyà-Solà, David M. Alba, “Fossil apes and human evolution”, Science  07 May 2021: Vol. 372, Issue 6542, eabb4363 DOI: https://doi.org/10.1126/science.abb4363


Provided by American Museum of Natural History

Dinosaurs That Hunted in the Dark (Paleontology)

The tiny desert-living dinosaur Shuvuuia had extraordinary vision and owl-like hearing for nocturnal life in the Mongolian desert

Today’s 10,000 species of birds live in virtually every habitat on Earth, but only a handful have adaptations enabling them to hunt active prey in the dark of night. Scientists have long wondered whether theropod dinosaurs – the group that gave rise to modern birds – had similar sensory adaptations.

A new study led by University of the Witwatersrand scientist, Professor Jonah Choiniere, sought to investigate how vision and hearing abilities of dinosaurs and birds compared. The international team of researchers used CT scanning and detailed measurements to collect information on the relative size of the eyes and inner ears of nearly 100 living bird and extinct dinosaur species.

Shuvuuia deserti artist’s reconstruction 2 © Viktor Radermaker

To measure hearing, the team measured the length of the lagena, the organ that processes incoming sound information (called the cochlea in mammals). The barn owl, which can hunt in complete darkness using hearing alone, has the proportionally longest lagena of any bird.

To assess vision, the team looked at the scleral ring, a series of bones surrounding the pupil, of each species. Like a camera lens, the larger the pupil can open, the more light can get in, enabling better vision at night. By measuring the diameter of the ring, the scientists could tell how much light the eye can gather.

The team found that many carnivorous theropods such as Tyrannosaurus and Dromaeosaurus had vision optimized for the daytime, and better-than-average hearing presumably to help them hunt. However, a diminutive theropod named Shuvuuia, part of a group known as alvarezsaurs, had both extraordinary hearing and night vision. The extremely large lagena of this species is almost identical in relative size to today’s barn owl, suggesting that Shuvuuia could have hunted in complete darkness.

The large lagena of Shuvuuia came as a surprise discovery to Dr. James Neenan, the joint first author of the study, and Choiniere’s former post-doc at Wits. “As I was digitally reconstructing the Shuvuuia skull, I couldn’t believe the lagena size…I called Prof. Choiniere to have a look. We both thought it might be a mistake, so I processed the other ear – only then did we realise what a cool discovery we had on our hands!” I couldn’t believe what I was seeing when I got there – dinosaur ears weren’t supposed to look like that!, “said Choiniere.

Prof. Jonah Choiniere holding a 3D printed model of the lagena of Shuvuuia deserti © Wits University

The eyes of Shuvuuia were also of note, as they had some of the proportionally largest pupils yet measured in birds or dinosaurs, suggesting that they could likely see very well at night.

Shuvuuia was a small dinosaur, about the size of a chicken, and it lived in the deserts of what is now Mongolia. Shuvuuia’s skeleton is among the most bizarre of all dinosaurs – it has a fragile, bird-like skull, brawny, weightlifter arms with a single claw on each hand, and long, roadrunner-like legs. This odd combination of features has baffled scientists since its discovery in the 1990s. With the new data on Shuvuuia’s senses, the scientific team hypothesizes that, like many desert animals, Shuvuuia would have foraged at night, using its hearing and vision to find prey like small mammals and insects, using its long legs to rapidly run that prey down, and using its strong forelimbs to pry the prey out of burrows or shrubby vegetation.

“Nocturnal activity, digging ability, and long hind limbs are all features of animals that live in deserts today,” said Choiniere, “but it’s surprising to see them all combined in a single dinosaur species that lived more than 65 million years ago.”

Featured image: Shuvuuia deserti artist’s reconstruction 1 © Viktor Radermaker


Reference: Jonah N. Choiniere, James M. Neenan et al., “Evolution of vision and hearing modalities in theropod dinosaurs”, Science  07 May 2021: Vol. 372, Issue 6542, pp. 610-613 DOI: 10.1126/science.abe7941


Provided by University of Witwatersrand

In A Cell-eat-cell World Calcium Ions Regulate Exposure Of ‘Eat-me’ Signal in Necrotic Cells (Biology)

Just as people keep their houses clean and clutter under control, a crew of cells in the body is in charge of clearing the waste the body generates, including dying cells. The housekeeping cells remove unwanted material by a process called phagocytosis, which literally means ‘eating cells.’ The housekeepers engulf and ingest the dying cells and break them down to effectively eliminate them.

“Phagocytosis is very important for the body’s health,” said Dr. Zheng Zhou, whose lab at Baylor College of Medicine has been studying phagocytosis for many years and provided key new insights into this essential process. “When this cell-eat-cell process fails, the dying cells will lose their integrity, break down and release their content into the surrounding tissues. Dumping the cell content would cause direct tissue damage and trigger inflammatory and autoimmune responses. If the dying cells are infected by a virus, releasing the cellular content would spread the infection.”

Dr. Zheng Zhou © BCM

In the current study, Zhou, professor in the Verna and Marrs McLean Department of Biochemistry and Molecular Biology at Baylor, and her colleagues focused on necrosis, the type of cell death caused by injury or disease. Necrosis is mostly associated with stroke, cancer, neurodegenerative diseases and heart conditions. The team investigated in more detail the signal necrotic cells display that cues the ‘eating’ or phagocytic cells to engulf and eliminate the dying cell.

Yoshitaka Furuta © BCM
Necrotic, but not living neurons, expose phosphatidylserine (PS) on their outer surface. Differential interference contrast (DIC) microscopy images of C. elegans show living neurons (panel A in green, white arrows) and necrotic, swollen neurons (panel C, white arrowhead). The corresponding bottom images show that only necrotic cells (D) have PS (in red) on their surface, while living neurons (B) do not expose PS and therefore do not pick up the red stain. Image courtesy of the authors/PLoS Genetics, 2021.

“In previous work, the Zhou lab showed that the signal in necrotic cells is phosphatidylserine, which is a type of lipid,” said Yoshitaka Furuta, first author of the current study on which he worked while he was an undergraduate student intern in the Zhou lab. Furuta currently is a student in Baylor’s Development, Disease Models and Therapeutics Graduate Program.

“The team found that necrotic cells, but not living cells, expose phosphatidylserine on their outer surfaces and when phagocytes detect it, they ingest and destroy the dying cells.”

Healthy cells keep phosphatidylserine in their inside, but when they are injured, for instance by lack of oxygen during a stroke when neurons are over excited due to constant entry of calcium ions, or during neurodegeneration, a process begins that ultimately flips phosphatidylserine to the outside of the cell. “We wanted to know what activates the flipping of phosphatidylserine,” Furuta said.

Following the process of necrosis in the transparent worm C. elegans

The researchers worked with the model organism C. elegans, a worm that is as long as a credit card is thick. C. elegans is transparent, which allows the researchers to visually identify necrotic neurons, which look swelled when compared to living cells, and follow changes in the dynamics of cellular components using a time-lapse recording approach they developed.

Previous work in C. elegans neurons had shown that certain mutations in ion channel proteins, which regulate the flow of ions like calcium2+ in and out of the cell, induced necrosis that was accompanied by an increase of calcium ion levels inside the cell. To investigate whether changes in calcium ion levels were linked to the triggering of the eat-me signal, the team introduced some of the ion channel mutant genes in neurons of their C. elegans model and monitored both calcium levels and phosphatidylserine over time.

“We discovered in our model of necrosis that a robust and transient increase in calcium ions inside the cell preceded phosphatidylserine exposure in necrotic neurons,” said Zhou, a member of Baylor’s Dan L Duncan Comprehensive Cancer Center. “Further experiments showed that necrotic neurons first had a small increase of calcium ions, which prompted the release of more calcium ions from an intracellular structure called the endoplasmic reticulum (ER), a larger source of calcium. Having larger than normal calcium levels inside the cell triggered phosphatidylserine exposure.”

A transient increase in the cytoplasmic Ca2+ level precedes subsequent exposure of phosphatidylserine (PS) on the surface of a necrotic neuron. Image courtesy of the authors/PLoS Genetics, 2021.

Supporting the role of calcium ions as a trigger of the ‘eat-cell’ signal, the researchers found that artificially increasing the level of calcium ions inside living cells also resulted in phosphatidylserine exposure and that suppressing calcium release from the ER prevented exposure of the signal.

The team also zoomed in into the process leading to the flipping of phosphatidylserine and found another piece of the puzzle. They discovered that a calcium increase inside the cells activates ANOH-1, an enzyme known to promote phosphatidylserine exposure.

“It was interesting to me that calcium can be good and bad for living cells,” Furuta said. “Too much calcium is toxic to cells and induces necrosis, but at the same time calcium is necessary for dying cells to expose phosphatidylserine, the eat-me signal that promotes their clearance.”

“Necrosis is a universal phenomenon that is present in many types of diseases and the clearance of necrotic cells is very important for keeping our bodies healthy,” Zhou said.

“Our findings provide new insight into the process of necrosis that can potentially lead to the development of therapeutic strategies, maybe along the lines of promoting clearance of necrotic cells by modulating phosphatidylserine exposure, which may help reduce the toxic effects of necrosis and improve cellular housekeeping.”

Find all the details of this study in the journal PLoS Genetics.

Omar Pena-Ramos, Zao Li and Lucia Chiao at Baylor College of Medicine also contributed to this work.

This project was supported by NIH grants R01GM104279 and R01GM067848 and the Tobitate Ryugaku JAPAN Nihondaihyou Program.

Featured image: Cartoon representation of the process of phagocytosis. Creative Commons.


Reference: Furuta Y, Pena-Ramos O, Li Z, Chiao L, Zhou Z (2021) Calcium ions trigger the exposure of phosphatidylserine on the surface of necrotic cells. PLoS Genet 17(2): e1009066. https://doi.org/10.1371/journal.pgen.1009066


Provided by Baylor College of Medicine